Host-pathogen interactions between the human innate immune system and Candida albicans—understanding and modeling defense and evasion strategies

PubMed Central

Dühring, Sybille; Germerodt, Sebastian; Skerka, Christine; Zipfel, Peter F.; Dandekar, Thomas; Schuster, Stefan

2015-01-01

The diploid, polymorphic yeast Candida albicans is one of the most important human pathogenic fungi. C. albicans can grow, proliferate and coexist as a commensal on or within the human host for a long time. However, alterations in the host environment can render C. albicans virulent. In this review, we describe the immunological cross-talk between C. albicans and the human innate immune system. We give an overview in form of pairs of human defense strategies including immunological mechanisms as well as general stressors such as nutrient limitation, pH, fever etc. and the corresponding fungal response and evasion mechanisms. Furthermore, Computational Systems Biology approaches to model and investigate these complex interactions are highlighted with a special focus on game-theoretical methods and agent-based models. An outlook on interesting questions to be tackled by Systems Biology regarding entangled defense and evasion mechanisms is given. PMID:26175718

Budding off: bringing functional genomics to Candida albicans.

PubMed

Anderson, Matthew Z; Bennett, Richard J

2016-03-01

Candida species are the most prevalent human fungal pathogens, with Candida albicans being the most clinically relevant species. Candida albicans resides as a commensal of the human gastrointestinal tract but is a frequent cause of opportunistic mucosal and systemic infections. Investigation of C. albicans virulence has traditionally relied on candidate gene approaches, but recent advances in functional genomics have now facilitated global, unbiased studies of gene function. Such studies include comparative genomics (both between and within Candida species), analysis of total RNA expression, and regulation and delineation of protein-DNA interactions. Additionally, large collections of mutant strains have begun to aid systematic screening of clinically relevant phenotypes. Here, we will highlight the development of functional genomics in C. albicans and discuss the use of these approaches to addressing both commensalism and pathogenesis in this species. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Cerebral Candidal Abscess and Bovine Viral Diarrhoea Virus Infection in an Aborted Bovine Fetus.

PubMed

Vilander, A C; Niles, G A; Frank, C B

2016-01-01

Candida species are opportunistic fungi associated with immunosuppression and are the most commonly isolated fungal pathogens from the human central nervous system. Invasive candidiasis is reported uncommonly in animals and there have only been two reports of candidal infection of the brain. This report presents a case of a cerebral candidal abscess in an aborted late-term calf co-infected with bovine viral diarrhoea virus. Candida etchellsii, a species not previously identified as pathogenic, was identified as the causative agent by polymerase chain reaction. Copyright © 2016 Elsevier Ltd. All rights reserved.

Genomic identification of potential targets unique to Candida albicans for the discovery of antifungal agents.

PubMed

Tripathi, Himanshu; Luqman, Suaib; Meena, Abha; Khan, Feroz

2014-01-01

Despite of modern antifungal therapy, the mortality rates of invasive infection with human fungal pathogen Candida albicans are up to 40%. Studies suggest that drug resistance in the three most common species of human fungal pathogens viz., C. albicans, Aspergillus fumigatus (causing mortality rate up to 90%) and Cryptococcus neoformans (causing mortality rate up to 70%) is due to mutations in the target enzymes or high expression of drug transporter genes. Drug resistance in human fungal pathogens has led to an imperative need for the identification of new targets unique to fungal pathogens. In the present study, we have used a comparative genomics approach to find out potential target proteins unique to C. albicans, an opportunistic fungus responsible for severe infection in immune-compromised human. Interestingly, many target proteins of existing antifungal agents showed orthologs in human cells. To identify unique proteins, we have compared proteome of C. albicans [SC5314] i.e., 14,633 total proteins retrieved from the RefSeq database of NCBI, USA with proteome of human and non-pathogenic yeast Saccharomyces cerevisiae. Results showed that 4,568 proteins were identified unique to C. albicans as compared to those of human and later when these unique proteins were compared with S. cerevisiae proteome, finally 2,161 proteins were identified as unique proteins and after removing repeats total 1,618 unique proteins (42 functionally known, 1,566 hypothetical and 10 unknown) were selected as potential antifungal drug targets unique to C. albicans.

Typing and virulence factors of food-borne Candida spp. isolates.

PubMed

Rajkowska, Katarzyna; Kunicka-Styczyńska, Alina

2018-08-20

Food-borne yeasts, excluding yeasts used as starter cultures, are commonly considered as food spoilage microorganisms. However, the incidence of non-C. albicans Candida (NCAC) infections has increased considerably over the past two decades. Although 15 Candida species are frequently identified as pathogens, a threat to human from food-borne Candida is poorly recognized. In the present study food-borne NCAC were characterized for the virulence factors, known to be associated with yeast pathogenicity. All food-borne strains in planktonic forms and 89% in biofilm structures represented biotypes established for C. albicans, and 61% demonstrated hemolytic activity. 56-94% of food-borne isolates formed biofilms on glass and biomaterials at a level comparable to clinical C. albicans. Nine out of eighteen tested food-borne NCAC strains (C. krusei, C. lusitaniae, C. famata, C. colliculosa, C. parapsilosis, C. tropicalis) showed similarity to clinical C. albicans in terms of their biotypes and the tested virulence factors, allocating them in a group of risk of potential pathogens. However, their capacity to grow at 37 °C seems to be the preliminary criterion in the study of potential virulence of food-borne yeasts. Copyright © 2018 Elsevier B.V. All rights reserved.

Evolutionary genomics of yeast pathogens in the Saccharomycotina

PubMed Central

Naranjo-Ortíz, Miguel A.; Marcet-Houben, Marina

2016-01-01

Saccharomycotina comprises a diverse group of yeasts that includes numerous species of industrial or clinical relevance. Opportunistic pathogens within this clade are often assigned to the genus Candida but belong to phylogenetically distant lineages that also comprise non-pathogenic species. This indicates that the ability to infect humans has evolved independently several times among Saccharomycotina. Although the mechanisms of infection of the main groups of Candida pathogens are starting to be unveiled, we still lack sufficient understanding of the evolutionary paths that led to a virulent phenotype in each of the pathogenic lineages. Deciphering what genomic changes underlie the evolutionary emergence of a virulence trait will not only aid the discovery of novel virulence mechanisms but it will also provide valuable information to understand how new pathogens emerge, and what clades may pose a future danger. Here we review recent comparative genomics efforts that have revealed possible evolutionary paths to pathogenesis in different lineages, focusing on the main three agents of candidiasis worldwide: Candida albicans, C. parapsilosis and C. glabrata. We will discuss what genomic traits may facilitate the emergence of virulence, and focus on two different genome evolution mechanisms able to generate drastic phenotypic changes and which have been associated to the emergence of virulence: gene family expansion and interspecies hybridization. PMID:27493146

DETECTION AND IDENTIFICATION OF PATHOGENIC CANDIDA SPECIES IN WATER USING FLOW CYTOMETRY COUPLED WITH TAQMAN PCR

EPA Science Inventory

As the incidence of human fungal infection increases, the ability to detect and identify pathogenic fungi in potential environmental reservoirs becomes increasingly important for disease control. PCR based assays are widely used for diagnostic purposes, but may be inadequate for...

Betamethasone augments the antifungal effect of menadione--towards a novel anti-Candida albicans combination therapy.

PubMed

Jakab, Ágnes; Emri, Tamás; Sipos, Lilla; Kiss, Ágnes; Kovács, Renátó; Dombrádi, Viktor; Kemény-Beke, Ádám; Balla, József; Majoros, László; Pócsi, István

2015-08-01

The fluorinated glucocorticoid betamethasone stimulated both the extracellular phospholipase production and hypha formation of the opportunistic human pathogen Candida albicans and also decreased the efficiency of the polyene antimycotics amphotericin B and nystatin against C. albicans in a dose-dependent manner. Importantly, betamethasone increased synergistically the anti-Candida activity of the oxidative stress generating agent menadione, which may be exploited in future combination therapies to prevent or cure C. albicans infections, in the field of dermatology. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Transcriptional Control of Drug Resistance, Virulence and Immune System Evasion in Pathogenic Fungi: A Cross-Species Comparison.

PubMed

Pais, Pedro; Costa, Catarina; Cavalheiro, Mafalda; Romão, Daniela; Teixeira, Miguel C

2016-01-01

Transcription factors are key players in the control of the activation or repression of gene expression programs in response to environmental stimuli. The study of regulatory networks taking place in fungal pathogens is a promising research topic that can help in the fight against these pathogens by targeting specific fungal pathways as a whole, instead of targeting more specific effectors of virulence or drug resistance. This review is focused on the analysis of regulatory networks playing a central role in the referred mechanisms in the human fungal pathogens Aspergillus fumigatus, Cryptococcus neoformans, Candida albicans, Candida glabrata, Candida parapsilosis , and Candida tropicalis . Current knowledge on the activity of the transcription factors characterized in each of these pathogenic fungal species will be addressed. Particular focus is given to their mechanisms of activation, regulatory targets and phenotypic outcome. The review further provides an evaluation on the conservation of transcriptional circuits among different fungal pathogens, highlighting the pathways that translate common or divergent traits among these species in what concerns their drug resistance, virulence and host immune evasion features. It becomes evident that the regulation of transcriptional networks is complex and presents significant variations among different fungal pathogens. Only the oxidative stress regulators Yap1 and Skn7 are conserved among all studied species; while some transcription factors, involved in nutrient homeostasis, pH adaptation, drug resistance and morphological switching are present in several, though not all species. Interestingly, in some cases not very homologous transcription factors display orthologous functions, whereas some homologous proteins have diverged in terms of their function in different species. A few cases of species specific transcription factors are also observed.

Characterization of Candida species isolated from cases of lower respiratory tract infection.

PubMed

Jha, B J; Dey, S; Tamang, M D; Joshy, M E; Shivananda, P G; Brahmadatan, K N

2006-01-01

(1) To identify and characterize the Candida species isolates from lower respiratory tract infection. (2) to determine the rate of isolation of Candida species from sputum samples. This study was carried out in the Department of Microbiology, Manipal Teaching Hospital, Pokhara, Nepal from June 2002 to January 2003. A total of 462 sputum samples were collected from patients suspected lower respiratory tract infection. The samples were processed as Gram staining to find out the suitability of the specimen, cultured on Sabouraud's Dextrose Agar (SDA) and also on blood agar and chocolate agar to identify the potential lower respiratory tract pathogens. For the identification of Candida, sputum samples were processed for Gram stain, culture, germ tube test, production of chlamydospore, sugar fermentation and assimilation test. For the identification of bacteria, Gram stain, culture, and biochemical tests were performed by standardized procedure. Out of 462 samples, 246 (53.24%) samples grew potential pathogens of lower respiratory tract. Among them Haemophilus influenzae 61(24.79%) and Streptococcus pneumoniae 57 (23.17%) were the predominant bacterial pathogens. Candida species were isolated from 30 samples (12.2%). The majority of Candida species amongst the Candida isolates were Candida albicans 21(70%) followed by Candida tropicalis 4(13.33%). Candida krusei 3(10%), Candida parapsilosis 1(3.33%) and Candida stellatoidea 1(3.33%). The highest rate of isolation of Candida was between the age of 71 and 80. Candida isolation from sputum samples is important as found in the present study in which Candida species were the third most common pathogen isolated from patients with lower respiratory tract infection.

Molecular mechanisms of mucocutaneous immunity against Candida and Staphylococci

PubMed Central

Maródi, László; Cypowyj, Sophie; Tóth, Beáta; Chernyshova, Liudmyla; Puel, Anne; Casanova, Jean-Laurent

2013-01-01

Signal transducer and activator of transcription (STAT) proteins are key components of the innate and adaptive immune responses to pathogenic microorganisms. Recent research on primary immunodeficiency disorders and the identification of patients carrying germline mutations in STAT1, STAT3, and STAT5B have highlighted the role of human STATs in host defense against various viruses, bacteria, and fungi. Mutations in STAT1 and STAT3 may disrupt various cytokine pathways that control mucocutaneous immunity against Candida species, especially Candida albicans, and Staphylococci, especially Staphylococcus aureus. Here, we consider inborn errors of immunity arising from mutations in either STAT1 or STAT3 that affect mucocutaneous immunity to Candida and Staphylococci. PMID:23040277

Candida species differ in their interactions with immature human gastrointestinal epithelial cells

PubMed Central

Falgier, Christina; Kegley, Sara; Podgorski, Heather; Heisel, Timothy; Storey, Kathleen; Bendel, Catherine M.; Gale, Cheryl A.

2011-01-01

Life-threatening gastrointestinal (GI) diseases of prematurity are highly associated with systemic candidiasis. This implicates the premature GI tract as an important site for invasion by Candida. Invasive interactions of Candida spp. with immature enterocytes have heretofore not been analyzed. Using a primary immature human enterocyte line, we compared the ability of multiple isolates of different Candida spp. to penetrate, injure, and induce a cytokine response from host cells. Of all the Candida spp. analyzed, C. albicans had the greatest ability to penetrate and injure immature enterocytes and to elicit interleukin-8 (IL-8) release (p < 0.01). In addition, C. albicans was the only Candida spp. to form filamentous hyphae when in contact with immature enterocytes. Similarly, a C. albicans mutant with defective hyphal morphogenesis and invasiveness had attenuated cytotoxicity for immature enterocytes (p < 0.003). Thus, hyphal morphogenesis correlates with immature enterocyte penetration, injury and inflammatory responses. Furthermore, variability in enterocyte injury was observed among hyphal-producing C. albicans strains suggesting that individual organism genotypes also influence host-pathogen interactions. Overall, the finding that Candida spp. differed in their interactions with immature enterocytes implicates that individual spp. may employ different pathogenesis mechanisms. PMID:21283049

Oxidative Stress Responses in the Human Fungal Pathogen, Candida albicans

PubMed Central

da Silva Dantas, Alessandra; Day, Alison; Ikeh, Mélanie; Kos, Iaroslava; Achan, Beatrice; Quinn, Janet

2015-01-01

Candida albicans is a major fungal pathogen of humans, causing approximately 400,000 life-threatening systemic infections world-wide each year in severely immunocompromised patients. An important fungicidal mechanism employed by innate immune cells involves the generation of toxic reactive oxygen species (ROS), such as superoxide and hydrogen peroxide. Consequently, there is much interest in the strategies employed by C. albicans to evade the oxidative killing by macrophages and neutrophils. Our understanding of how C. albicans senses and responds to ROS has significantly increased in recent years. Key findings include the observations that hydrogen peroxide triggers the filamentation of this polymorphic fungus and that a superoxide dismutase enzyme with a novel mode of action is expressed at the cell surface of C. albicans. Furthermore, recent studies have indicated that combinations of the chemical stresses generated by phagocytes can actively prevent C. albicans oxidative stress responses through a mechanism termed the stress pathway interference. In this review, we present an up-date of our current understanding of the role and regulation of oxidative stress responses in this important human fungal pathogen. PMID:25723552

Application of an oligonucleotide microarray-based nano-amplification technique for the detection of fungal pathogens.

PubMed

Lu, Weiping; Gu, Dayong; Chen, Xingyun; Xiong, Renping; Liu, Ping; Yang, Nan; Zhou, Yuanguo

2010-10-01

The traditional techniques for diagnosis of invasive fungal infections in the clinical microbiology laboratory need improvement. These techniques are prone to delay results due to their time-consuming process, or result in misidentification of the fungus due to low sensitivity or low specificity. The aim of this study was to develop a method for the rapid detection and identification of fungal pathogens. The internal transcribed spacer two fragments of fungal ribosomal DNA were amplified using a polymerase chain reaction for all samples. Next, the products were hybridized with the probes immobilized on the surface of a microarray. These species-specific probes were designed to detect nine different clinical pathogenic fungi including Candida albicans, Candida tropocalis, Candida glabrata, Candida parapsilosis, Candida krusei, Candida lusitaniae, Candida guilliermondii, Candida keyfr, and Cryptococcus neoformans. The hybridizing signals were enhanced with gold nanoparticles and silver deposition, and detected using a flatbed scanner or visually. Fifty-nine strains of fungal pathogens, including standard and clinically isolated strains, were correctly identified by this method. The sensitivity of the assay for Candida albicans was 10 cells/mL. Ten cultures from clinical specimens and 12 clinical samples spiked with fungi were also identified correctly. This technique offers a reliable alternative to conventional methods for the detection and identification of fungal pathogens. It has higher efficiency, specificity and sensitivity compared with other methods commonly used in the clinical laboratory.

Gene flow contributes to diversification of the major fungal pathogen Candida albicans.

PubMed

Ropars, Jeanne; Maufrais, Corinne; Diogo, Dorothée; Marcet-Houben, Marina; Perin, Aurélie; Sertour, Natacha; Mosca, Kevin; Permal, Emmanuelle; Laval, Guillaume; Bouchier, Christiane; Ma, Laurence; Schwartz, Katja; Voelz, Kerstin; May, Robin C; Poulain, Julie; Battail, Christophe; Wincker, Patrick; Borman, Andrew M; Chowdhary, Anuradha; Fan, Shangrong; Kim, Soo Hyun; Le Pape, Patrice; Romeo, Orazio; Shin, Jong Hee; Gabaldon, Toni; Sherlock, Gavin; Bougnoux, Marie-Elisabeth; d'Enfert, Christophe

2018-06-08

Elucidating population structure and levels of genetic diversity and recombination is necessary to understand the evolution and adaptation of species. Candida albicans is the second most frequent agent of human fungal infections worldwide, causing high-mortality rates. Here we present the genomic sequences of 182 C. albicans isolates collected worldwide, including commensal isolates, as well as ones responsible for superficial and invasive infections, constituting the largest dataset to date for this major fungal pathogen. Although, C. albicans shows a predominantly clonal population structure, we find evidence of gene flow between previously known and newly identified genetic clusters, supporting the occurrence of (para)sexuality in nature. A highly clonal lineage, which experimentally shows reduced fitness, has undergone pseudogenization in genes required for virulence and morphogenesis, which may explain its niche restriction. Candida albicans thus takes advantage of both clonality and gene flow to diversify.

Sequence variations and protein expression levels of the two immune evasion proteins Gpm1 and Pra1 influence virulence of clinical Candida albicans isolates.

PubMed

Luo, Shanshan; Hipler, Uta-Christina; Münzberg, Christin; Skerka, Christine; Zipfel, Peter F

2015-01-01

Candida albicans, the important human fungal pathogen uses multiple evasion strategies to control, modulate and inhibit host complement and innate immune attack. Clinical C. albicans strains vary in pathogenicity and in serum resistance, in this work we analyzed sequence polymorphisms and variations in the expression levels of two central fungal complement evasion proteins, Gpm1 (phosphoglycerate mutase 1) and Pra1 (pH-regulated antigen 1) in thirteen clinical C. albicans isolates. Four nucleotide (nt) exchanges, all representing synonymous exchanges, were identified within the 747-nt long GPM1 gene. For the 900-nt long PRA1 gene, sixteen nucleotide exchanges were identified, which represented synonymous, as well as non-synonymous exchanges. All thirteen clinical isolates had a homozygous exchange (A to G) at position 73 of the PRA1 gene. Surface levels of Gpm1 varied by 8.2, and Pra1 levels by 3.3 fold in thirteen tested isolates and these differences influenced fungal immune fitness. The high Gpm1/Pra1 expressing candida strains bound the three human immune regulators more efficiently, than the low expression strains. The difference was 44% for Factor H binding, 51% for C4BP binding and 23% for plasminogen binding. This higher Gpm1/Pra1 expressing strains result in enhanced survival upon challenge with complement active, Factor H depleted human serum (difference 40%). In addition adhesion to and infection of human endothelial cells was increased (difference 60%), and C3b surface deposition was less effective (difference 27%). Thus, variable expression levels of central immune evasion protein influences immune fitness of the human fungal pathogen C. albicans and thus contribute to fungal virulence.

Evolutionary relationships among pathogenic Candida species and relatives.

PubMed Central

Barns, S M; Lane, D J; Sogin, M L; Bibeau, C; Weisburg, W G

1991-01-01

Small subunit rRNA sequences have been determined for 10 of the most clinically important pathogenic species of the yeast genus Candida (including Torulopsis [Candida] glabrata and Yarrowia [Candida] lipolytica) and for Hansenula polymorpha. Phylogenetic analyses of these sequences and those of Saccharomyces cerevisiae, Kluyveromyces marxianus var. lactis, and Aspergillus fumigatus indicate that Candida albicans, C. tropicalis, C. parapsilosis, and C. viswanathii form a subgroup within the genus. The remaining significant pathogen, T. glabrata, falls into a second, distinct subgroup and is specifically related to S. cerevisiae and more distantly related to C. kefyr (psuedotropicalis) and K. marxianus var. lactis. The 18S rRNA sequence of Y. lipolytica has evolved rapidly in relation to the other Candida sequences examined and appears to be only distantly related to them. As anticipated, species of several other genera appear to bear specific relationships to members of the genus Candida. PMID:2007550

Mitochondrial Cochaperone Mge1 Is Involved in Regulating Susceptibility to Fluconazole in Saccharomyces cerevisiae and Candida Species.

PubMed

Demuyser, Liesbeth; Swinnen, Erwin; Fiori, Alessandro; Herrera-Malaver, Beatriz; Vestrepen, Kevin; Van Dijck, Patrick

2017-07-18

MGE1 encodes a yeast chaperone involved in Fe-S cluster metabolism and protein import into the mitochondria. In this study, we identified MGE1 as a multicopy suppressor of susceptibility to the antifungal fluconazole in the model yeast Saccharomyces cerevisiae We demonstrate that this phenomenon is not exclusively dependent on the integrity of the mitochondrial DNA or on the presence of the drug efflux pump Pdr5. Instead, we show that the increased dosage of Mge1 plays a protective role by retaining increased amounts of ergosterol upon fluconazole treatment. Iron metabolism and, more particularly, Fe-S cluster formation are involved in regulating this process, since the responsible Hsp70 chaperone, Ssq1, is required. Additionally, we show the necessity but, by itself, insufficiency of activating the iron regulon in establishing the Mge1-related effect on drug susceptibility. Finally, we confirm a similar role for Mge1 in fluconazole susceptibility in the pathogenic fungi Candida glabrata and Candida albicans IMPORTANCE Although they are mostly neglected compared to bacterial infections, fungal infections pose a serious threat to the human population. While some of them remain relatively harmless, infections that reach the bloodstream often become lethal. Only a few therapies are available, and resistance of the pathogen to these drugs is a frequently encountered problem. It is thus essential that more research is performed on how these pathogens cope with the treatment and cause recurrent infections. Baker's yeast is often used as a model to study pathogenic fungi. We show here, by using this model, that iron metabolism and the formation of the important iron-sulfur clusters are involved in regulating susceptibility to fluconazole, the most commonly used antifungal drug. We show that the same process likely also occurs in two of the most regularly isolated pathogenic fungi, Candida glabrata and Candida albicans . Copyright © 2017 Demuyser et al.

Development of a CRISPR-Cas9 System for Efficient Genome Editing of Candida lusitaniae.

PubMed

Norton, Emily L; Sherwood, Racquel K; Bennett, Richard J

2017-01-01

Candida lusitaniae is a member of the Candida clade that includes a diverse group of fungal species relevant to both human health and biotechnology. This species exhibits a full sexual cycle to undergo interconversion between haploid and diploid forms. C. lusitaniae is also an emerging opportunistic pathogen that can cause serious bloodstream infections in the clinic and yet has often proven to be refractory to facile genetic manipulations. In this work, we develop a clustered regularly interspaced short palindromic repeat (CRISPR) and CRISPR-associated gene 9 (Cas9) system to enable genome editing of C. lusitaniae . We demonstrate that expression of CRISPR-Cas9 components under species-specific promoters is necessary for efficient gene targeting and can be successfully applied to multiple genes in both haploid and diploid isolates. Gene deletion efficiencies with CRISPR-Cas9 were further enhanced in C. lusitaniae strains lacking the established nonhomologous end joining (NHEJ) factors Ku70 and DNA ligase 4. These results indicate that NHEJ plays an important role in directing the repair of DNA double-strand breaks (DSBs) in C. lusitaniae and that removal of this pathway increases integration of gene deletion templates by homologous recombination. The described approaches significantly enhance the ability to perform genetic studies in, and promote understanding of, this emerging human pathogen and model sexual species. IMPORTANCE The ability to perform efficient genome editing is a key development for detailed mechanistic studies of a species. Candida lusitaniae is an important member of the Candida clade and is relevant both as an emerging human pathogen and as a model for understanding mechanisms of sexual reproduction. We highlight the development of a CRISPR-Cas9 system for efficient genome manipulation in C. lusitaniae and demonstrate the importance of species-specific promoters for expression of CRISPR components. We also demonstrate that the NHEJ pathway contributes to non-template-mediated repair of DNA DSBs and that removal of this pathway enhances efficiencies of gene targeting by CRISPR-Cas9. These results therefore establish important genetic tools for further exploration of C. lusitaniae biology.

A Novel Flucytosine-Resistant Yeast Species, Candida pseudoaaseri, Causes Disease in a Cancer Patient ▿

PubMed Central

Pfüller, Roland; Gräser, Yvonne; Erhard, Marcel; Groenewald, Marizeth

2011-01-01

Some members of the genus Candida are among the most common human fungal pathogens and cause serious diseases especially in immunocompromised people. A yeast was isolated from a blood culture from an immunocompromised cancer patient who suffered from acute pneumonia. The growth characteristics of the yeast on CHROMagar Candida were similar to those of Candida tropicalis, whereas the API ID 32C system identified the yeast as Candida silvicola. On the basis of the nucleotide divergence in the D1/D2 domain of the 26S nuclear rRNA (nrRNA) gene, as well as the internal transcribed spacer (ITS) domain of the nrRNA gene region, a new species, Candida pseudoaaseri sp. nov. with type strain VK065094 (CBS 11170T), which was found to be closely related to Candida aaseri, is proposed. While C. aaseri strains were susceptible to all tested antifungals, the new species is resistant to flucytosine and may also be distinguished from C. aaseri by its ability to assimilate l-rhamnose, whereas its colony morphology on CHROMagar Candida may be helpful for differentiation. PMID:21976765

The oxidative stress response of the opportunistic fungal pathogen Candida glabrata.

PubMed

Briones-Martin-Del-Campo, Marcela; Orta-Zavalza, Emmanuel; Juarez-Cepeda, Jacqueline; Gutierrez-Escobedo, Guadalupe; Cañas-Villamar, Israel; Castaño, Irene; De Las Peñas, Alejandro

2014-01-01

Organisms have evolved different strategies to respond to oxidative stress generated as a by-product of aerobic respiration and thus maintain the redox homeostasis within the cell. In particular, fungal pathogens are exposed to reactive oxygen species (ROS) when they interact with the phagocytic cells of the host which are the first line of defense against fungal infections. These pathogens have co-opted the enzymatic (catalases, superoxide dismutases (SODs), and peroxidases) and non-enzymatic (glutathione) mechanisms used to maintain the redox homeostasis within the cell, to resist oxidative stress and ensure survival within the host. Several virulence factors have been related to the response to oxidative stress in pathogenic fungi. The opportunistic fungal pathogen Candida glabrata (C. glabrata) is the second most common cause of candidiasis after Candida albicans (C. albicans). C. glabrata has a well defined oxidative stress response (OSR), which include both enzymatic and non-enzymatic mechanisms. C. glabrata OSR is controlled by the well-conserved transcription factors Yap1, Skn7, Msn2 and Msn4. In this review, we describe the OSR of C. glabrata, what is known about its core elements, its regulation and how C. glabrata interacts with the host. This manuscript is part of the series of works presented at the "V International Workshop: Molecular genetic approaches to the study of human pathogenic fungi" (Oaxaca, Mexico, 2012). Copyright © 2013 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

Structure of Protein Geranylgeranyltransferase-I from the Human Pathogen Candida albicans Complexed with a Lipid Substrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hast, Michael A.; Beese, Lorena S.

2008-11-21

Protein geranylgeranyltransferase-I (GGTase-I) catalyzes the transfer of a 20-carbon isoprenoid lipid to the sulfur of a cysteine residue located near the C terminus of numerous cellular proteins, including members of the Rho superfamily of small GTPases and other essential signal transduction proteins. In humans, GGTase-I and the homologous protein farnesyltransferase (FTase) are targets of anticancer therapeutics because of the role small GTPases play in oncogenesis. Protein prenyltransferases are also essential for many fungal and protozoan pathogens that infect humans, and have therefore become important targets for treating infectious diseases. Candida albicans, a causative agent of systemic fungal infections in immunocompromisedmore » individuals, is one pathogen for which protein prenylation is essential for survival. Here we present the crystal structure of GGTase-I from C. albicans (CaGGTase-I) in complex with its cognate lipid substrate, geranylgeranylpyrophosphate. This structure provides a high-resolution picture of a non-mammalian protein prenyltransferase. There are significant variations between species in critical areas of the active site, including the isoprenoid-binding pocket, as well as the putative product exit groove. These differences indicate the regions where specific protein prenyltransferase inhibitors with antifungal activity can be designed.« less

Adhesins in Human Fungal Pathogens: Glue with Plenty of Stick

PubMed Central

de Groot, Piet W. J.; Bader, Oliver; de Boer, Albert D.; Weig, Michael

2013-01-01

Understanding the pathogenesis of an infectious disease is critical for developing new methods to prevent infection and diagnose or cure disease. Adherence of microorganisms to host tissue is a prerequisite for tissue invasion and infection. Fungal cell wall adhesins involved in adherence to host tissue or abiotic medical devices are critical for colonization leading to invasion and damage of host tissue. Here, with a main focus on pathogenic Candida species, we summarize recent progress made in the field of adhesins in human fungal pathogens and underscore the importance of these proteins in establishment of fungal diseases. PMID:23397570

Purification and characterization of antifungal phenazines from a fluorescent Pseudomonas strain FPO4 against medically important fungi.

PubMed

Gorantla, J N; Kumar, S Nishanth; Nisha, G V; Sumandu, A S; Dileep, C; Sudaresan, A; Kumar, M M Sree; Lankalapalli, R S; Kumar, B S Dileep

2014-09-01

The strain FPO4 was isolated from the rhizoplane of rice plant root and identified as a fluorescent Pseudomonas aeruginosa on the basis of 16S rDNA sequences and BLAST analysis. The extracellular metabolites produced by this strain were purified by silica gel column chromatography and isolated four pure compounds. Based on the spectral data the four compounds were identified as phenazin-1-ol, phenazine-1-carboxylic acid (PCA), 2-heptyl-3-hydroxyl-4(1H)-quinolone (PQS), and phenazine-1-carboxamide (PCN), respectively. Phenazin-1-ol and PCA were active against all the eight fungi tested. The highest activity of 4 μg/mL by PCA was recorded against Trichophyton rubrum, a human pathogen responsible for causing athlete's foot, jock itch, ringworm and fingernail fungus infections, followed by Candida albicans and Candida tropicalis. The activity of phenazin-1-ol, PCA against Candida spp. was found to be better than the standard antifungal agent amphotericin B. Furthermore, the present study reports the antimicrobial activity of the purified phenazines on major human pathogen, T. rubrum for the first time. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Molecular mechanisms of mucocutaneous immunity against Candida and Staphylococcus species.

PubMed

Maródi, László; Cypowyj, Sophie; Tóth, Beáta; Chernyshova, Liudmyla; Puel, Anne; Casanova, Jean-Laurent

2012-11-01

Signal transducer and activator of transcription (STAT) proteins are key components of the innate and adaptive immune responses to pathogenic microorganisms. Recent research on primary immunodeficiency disorders and the identification of patients carrying germline mutations in STAT1, STAT3, and STAT5B have highlighted the role of human STATs in host defense against various viruses, bacteria, and fungi. Mutations in STAT1 and STAT3 disrupt various cytokine pathways that control mucocutaneous immunity against Candida species, especially Candida albicans, and Staphylococcus species, especially Staphylococcus aureus. Here we consider inborn errors of immunity arising from mutations in either STAT1 or STAT3 that affect mucocutaneous immunity to Candida and Staphylococcus species. Copyright © 2012 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

Comparative Evolution of Morphological Regulatory Functions in Candida Species

PubMed Central

Lackey, Erika; Vipulanandan, Geethanjali; Childers, Delma S.

2013-01-01

Morphological transitions play an important role in virulence and virulence-related processes in a wide variety of pathogenic fungi, including the most commonly isolated human fungal pathogen Candida albicans. While environmental signals, transcriptional regulators, and target genes associated with C. albicans morphogenesis are well-characterized, considerably little is known about morphological regulatory mechanisms and the extent to which they are evolutionarily conserved in less pathogenic and less filamentous non-albicans Candida species (NACS). We have identified specific optimal filament-inducing conditions for three NACS (C. tropicalis, C. parapsilosis, and C. guilliermondii), which are very limited, suggesting that these species may be adapted for niche-specific filamentation in the host. Only a subset of evolutionarily conserved C. albicans filament-specific target genes were induced upon filamentation in C. tropicalis, C. parapsilosis, and C. guilliermondii. One of the genes showing conserved expression was UME6, a key filament-specific regulator of C. albicans hyphal development. Constitutive high-level expression of UME6 was sufficient to drive increased filamentation as well as biofilm formation and partly restore conserved filament-specific gene expression in both C. tropicalis and C. parapsilosis, suggesting that evolutionary differences in filamentation ability among pathogenic Candida species may be partially attributed to alterations in the expression level of a conserved filamentous growth machinery. In contrast to UME6, NRG1, an important repressor of C. albicans filamentation, showed only a partly conserved role in controlling NACS filamentation. Overall, our results suggest that C. albicans morphological regulatory functions are partially conserved in NACS and have evolved to respond to more specific sets of host environmental cues. PMID:23913541

[Presumptive identification of Candida spp. and other clinically important yeasts: usefulness of Brilliance Candida Agar].

PubMed

Alfonso, Claudia; López, Mónica; Arechavala, Alicia; Perrone, María Del Carmen; Guelfand, Liliana; Bianchi, Mario

2010-06-30

Fungal infections caused by yeasts have increased during the last decades and invasive forms represent a serious problem for human health. Candida albicans is the species most frequently isolated from clinical samples. However, other emerging yeast pathogens are increasingly responsible for mycotic infections, and some of them are resistant to some antifungal drugs. Consequently, it is necessary to have methods that can provide a rapid presumptive identification at species level. Numerous chromogenic agar media have been shown to be of value as diagnostic tools. We have compared a chromogenic medium, Brilliance Candida Agar, with CHROMagar Candida, the chromogenic medium most used in our country. A multicentre study was conducted in 16 Hospitals belonging to the Mycology Net of Buenos Aires City Government. A total of 240 yeast isolates were included in this research. The new chromogenic agar showed results very similar to those obtained with CHROMagar Candida. Copyright 2009 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

Periorbital Necrotizing Fasciitis Secondary to Candida parapsilosis and Streptococcus pyogenes.

PubMed

Zhang, Matthew; Chelnis, James; Mawn, Louise A

Necrotizing fasciitis is most often caused by either polymicrobial bacterial infections or by Gram-positive organisms, such as Streptococcus or Staphylococcus; however, rare cases of fungal necrotizing fasciitis have been reported. Candida parapsilosis is an emerging fungal pathogen. This fungus grows in either a yeast or pseudohyphal form. C. parapsilosis has been reported to cause keratitis, intraocular infection, and seeding of frontalis slings. C. parapsilosis is a commensal of human skin and can be acquired by nosocomial spread. Necrotizing fasciitis due to Candida has rarely been reported, but to date C. parapsilosis has not been identified as the causative organism in necrotizing fasciitis. This is the first documented case of human periocular soft tissue infection by C. parapsilosis, and also the first report providing evidence of mycotic infection in a necrotizing fasciitis concurrently infected by Streptococcus pyogenes.

New secondary metabolites from bioactive extracts of the fungus Armillaria tabescens

USDA-ARS?s Scientific Manuscript database

Ethyl acetate extracts of Armillaria tabescens (strain JNB-OZ344) mycelium showed significant fungistatic and bacteristatic activities against several major human pathogens including Candida albicans, Cryptococcus neoformans, Escherichia coli and Mycobacterium intracellulare. Chemical analysis of th...

Molecular genetic techniques for gene manipulation in Candida albicans.

PubMed

Xu, Qiu-Rong; Yan, Lan; Lv, Quan-Zhen; Zhou, Mi; Sui, Xue; Cao, Yong-Bing; Jiang, Yuan-Ying

2014-05-15

Candida albicans is one of the most common fungal pathogen in humans due to its high frequency as an opportunistic and pathogenic fungus causing superficial as well as invasive infections in immunocompromised patients. An understanding of gene function in C. albicans is necessary to study the molecular basis of its pathogenesis, virulence and drug resistance. Several manipulation techniques have been used for investigation of gene function in C. albicans, including gene disruption, controlled gene expression, protein tagging, gene reintegration, and overexpression. In this review, the main cassettes containing selectable markers used for gene manipulation in C. albicans are summarized; the advantages and limitations of these cassettes are discussed concerning the influences on the target gene expression and the virulence of the mutant strains.

Asarones from Acorus calamus in combination with azoles and amphotericin B: a novel synergistic combination to compete against human pathogenic Candida species in vitro.

PubMed

Kumar, S Nishanth; Aravind, S R; Sreelekha, T T; Jacob, Jubi; Kumar, B S Dileep

2015-04-01

The increase in drug resistance to current antifungal drugs brings enormous challenges to the management of Candida infection. Therefore, there is a continuous need for the discovery of new antimicrobial agents that are effective against Candida infections especially from natural source especially from medical plants. The present investigation describes the synergistic anticandidal activity of two asarones (∞ and β) purified from Acorus calamus in combination with three clinically used antifungal drugs (fluconazole, clotrimazole, and amphotericin B). The synergistic anticandidal activities of asarones and drugs were assessed using the checkerboard microdilution and time-kill assays. The results of the present study showed that the combined effects of asarones and drugs principally recorded substantial synergistic activity (fractional inhibitory concentration index (FICI) <0.5). Time-kill study by combination of the minimal inhibitory concentration (MIC) of asarones and drugs (1:1) recorded that the growth of the Candida species was significantly arrested between 0 and 2 h and almost completely attenuated between 2 and 6 h of treatment. These findings have potential implications in adjourning the development of resistance as the anticandidal activity is achieved with lower concentrations of asarones and drugs. The combination of asarones and drugs also significantly inhibit the biofilm formation by Candida species, and this would also help to fight against drug resistance because biofilms formed by Candida species are ubiquitous in nature and are characterized by their recalcitrance toward antimicrobial treatment. The in vitro synergistic activity of asarones and drugs against pathogenic Candida species is reported here for the first time.

Specific Human and Candida Cellular Interactions Lead to Controlled or Persistent Infection Outcomes during Granuloma-Like Formation

PubMed Central

Misme-Aucouturier, Barbara; Albassier, Marjorie

2016-01-01

ABSTRACT A delayed type of multicellular process could be crucial during chronic candidiasis in determining the course of infection. This reaction, consisting of organized immune cells surrounding the pathogen, initiates an inflammatory response to avoid fungal dissemination. The goal of the present study was to examine, at an in vitro cellular scale, Candida and human immune cell interaction dynamics during a long-term period. By challenging human peripheral blood immune cells from 10 healthy donors with 32 Candida albicans and non-albicans (C. glabrata, C. tropicalis, C. parapsilosis, C. dubliniensis, C. lusitaniae, C. krusei, and C. kefyr) clinical isolates, we showed that Candida spp. induced the formation of granuloma-like structures within 6 days after challenge, but their sizes and the respective fungal burdens differed according to the Candida species. These two parameters are positively correlated. Phenotypic characteristics, such as hypha formation and higher axenic growth rate, seem to contribute to yeast persistence within granuloma-like structures. We showed an interindividual variability of the human response against Candida spp. Higher proportions of neutrophils and elevated CD4+/CD8+ T cell ratios during the first days after challenge were correlated with early production of gamma interferon (IFN-γ) and associated with controlled infection. In contrast, the persistence of Candida could result from upregulation of proinflammatory cytokines such as interleukin-6 (IL-6), IFN-γ, and tumor necrosis factor alpha (TNF-α) and a poor anti-inflammatory negative feedback (IL-10). Importantly, regulatory subsets of NK cells and CD4lo CD8hi doubly positive (DP) lymphocytes at late stage infiltrate granuloma-like structures and could correlate with the IL-10 and TNF-α production. These data offer a base frame to explain cellular events that guide infection control or fungal persistence. PMID:27799331

The Endoplasmic Reticulum-Mitochondrion Tether ERMES Orchestrates Fungal Immune Evasion, Illuminating Inflammasome Responses to Hyphal Signals

PubMed Central

Tucey, Timothy M.; Verma-Gaur, Jiyoti; Nguyen, Julie; Hewitt, Victoria L.; Lo, Tricia L.; Shingu-Vazquez, Miguel; Robertson, Avril A. B.; Hill, James R.; Pettolino, Filomena A.; Beddoe, Travis; Cooper, Matthew A.; Naderer, Thomas

2016-01-01

ABSTRACT The pathogenic yeast Candida albicans escapes macrophages by triggering NLRP3 inflammasome-dependent host cell death (pyroptosis). Pyroptosis is inflammatory and must be tightly regulated by host and microbe, but the mechanism is incompletely defined. We characterized the C. albicans endoplasmic reticulum (ER)-mitochondrion tether ERMES and show that the ERMES mmm1 mutant is severely crippled in killing macrophages despite hyphal formation and normal phagocytosis and survival. To understand dynamic inflammasome responses to Candida with high spatiotemporal resolution, we established live-cell imaging for parallel detection of inflammasome activation and pyroptosis at the single-cell level. This showed that the inflammasome response to mmm1 mutant hyphae is delayed by 10 h, after which an exacerbated activation occurs. The NLRP3 inhibitor MCC950 inhibited inflammasome activation and pyroptosis by C. albicans, including exacerbated inflammasome activation by the mmm1 mutant. At the cell biology level, inactivation of ERMES led to a rapid collapse of mitochondrial tubular morphology, slow growth and hyphal elongation at host temperature, and reduced exposed 1,3-β-glucan in hyphal populations. Our data suggest that inflammasome activation by C. albicans requires a signal threshold dependent on hyphal elongation and cell wall remodeling, which could fine-tune the response relative to the level of danger posed by C. albicans. The phenotypes of the ERMES mutant and the lack of conservation in animals suggest that ERMES is a promising antifungal drug target. Our data further indicate that NLRP3 inhibition by MCC950 could modulate C. albicans-induced inflammation. IMPORTANCE The yeast Candida albicans causes human infections that have mortality rates approaching 50%. The key to developing improved therapeutics is to understand the host-pathogen interface. A critical interaction is that with macrophages: intracellular Candida triggers the NLRP3/caspase-1 inflammasome for escape through lytic host cell death, but this also activates antifungal responses. To better understand how the inflammasome response to Candida is fine-tuned, we established live-cell imaging of inflammasome activation at single-cell resolution, coupled with analysis of the fungal ERMES complex, a mitochondrial regulator that lacks human homologs. We show that ERMES mediates Candida escape via inflammasome-dependent processes, and our data suggest that inflammasome activation is controlled by the level of hyphal growth and exposure of cell wall components as a proxy for severity of danger. Our study provides the most detailed dynamic analysis of inflammasome responses to a fungal pathogen so far and establishes promising pathogen- and host-derived therapeutic strategies. PMID:27303738

The Endoplasmic Reticulum-Mitochondrion Tether ERMES Orchestrates Fungal Immune Evasion, Illuminating Inflammasome Responses to Hyphal Signals.

PubMed

Tucey, Timothy M; Verma-Gaur, Jiyoti; Nguyen, Julie; Hewitt, Victoria L; Lo, Tricia L; Shingu-Vazquez, Miguel; Robertson, Avril A B; Hill, James R; Pettolino, Filomena A; Beddoe, Travis; Cooper, Matthew A; Naderer, Thomas; Traven, Ana

2016-01-01

The pathogenic yeast Candida albicans escapes macrophages by triggering NLRP3 inflammasome-dependent host cell death (pyroptosis). Pyroptosis is inflammatory and must be tightly regulated by host and microbe, but the mechanism is incompletely defined. We characterized the C. albicans endoplasmic reticulum (ER)-mitochondrion tether ERMES and show that the ERMES mmm1 mutant is severely crippled in killing macrophages despite hyphal formation and normal phagocytosis and survival. To understand dynamic inflammasome responses to Candida with high spatiotemporal resolution, we established live-cell imaging for parallel detection of inflammasome activation and pyroptosis at the single-cell level. This showed that the inflammasome response to mmm1 mutant hyphae is delayed by 10 h, after which an exacerbated activation occurs. The NLRP3 inhibitor MCC950 inhibited inflammasome activation and pyroptosis by C. albicans, including exacerbated inflammasome activation by the mmm1 mutant. At the cell biology level, inactivation of ERMES led to a rapid collapse of mitochondrial tubular morphology, slow growth and hyphal elongation at host temperature, and reduced exposed 1,3-β-glucan in hyphal populations. Our data suggest that inflammasome activation by C. albicans requires a signal threshold dependent on hyphal elongation and cell wall remodeling, which could fine-tune the response relative to the level of danger posed by C. albicans. The phenotypes of the ERMES mutant and the lack of conservation in animals suggest that ERMES is a promising antifungal drug target. Our data further indicate that NLRP3 inhibition by MCC950 could modulate C. albicans-induced inflammation. IMPORTANCE The yeast Candida albicans causes human infections that have mortality rates approaching 50%. The key to developing improved therapeutics is to understand the host-pathogen interface. A critical interaction is that with macrophages: intracellular Candida triggers the NLRP3/caspase-1 inflammasome for escape through lytic host cell death, but this also activates antifungal responses. To better understand how the inflammasome response to Candida is fine-tuned, we established live-cell imaging of inflammasome activation at single-cell resolution, coupled with analysis of the fungal ERMES complex, a mitochondrial regulator that lacks human homologs. We show that ERMES mediates Candida escape via inflammasome-dependent processes, and our data suggest that inflammasome activation is controlled by the level of hyphal growth and exposure of cell wall components as a proxy for severity of danger. Our study provides the most detailed dynamic analysis of inflammasome responses to a fungal pathogen so far and establishes promising pathogen- and host-derived therapeutic strategies.

An in vitro study of antifungal drug susceptibility of Candida species isolated from human immunodeficiency virus seropositive and human immunodeficiency virus seronegative individuals in Lucknow population Uttar Pradesh.

PubMed

Dar, Mohammad Shafi; Sreedar, Gadiputi; Shukla, Abhilasha; Gupta, Prashant; Rehan, Ahmad Danish; George, Jiji

2015-01-01

Candidiasis is the most common opportunistic infection in human immunodeficiency virus (HIV) seropositive patients, starting from asymptomatic colonization to pathogenic forms and gradual colonization of non-albicans in patients with advanced immunosuppression leads to resistance for azole group of antifungal drugs with high rate of morbidity and mortality. To isolate the Candida species and determine of antifungal drug susceptibility against fluconazole, itraconazole, nystatin, amphotericin B, and clotrimazolein HIV seropositive and control individuals, with or without clinical oropharyngeal candidiasis (OPC). Includes samples from faucial region of 70 subjects with and without clinical candidiasis in HIV seropositive and controls were aseptically inoculated onto Sabaraud's Dextrose Agar media and yeasts were identified for the specific species by Corn Meal Agar, sugar fermentation and heat tolerance tests. Antifungal drug susceptibility of the isolated species was done against above-mentioned drugs by E-test and disc diffusion method. The commonly isolated species in HIV seropositive and controls were Candida albicans, Candida glabrata and Candida tropicalis Candida guilliermondii and Candida dubliniensis isolated only in HIV seropositive patients. Susceptibility against selected antifungal drugs was observed more in HIV-negative individuals whereas susceptible dose-dependent and resistance were predominant in HIV-positive patients. Resistance is the major problem in the therapy of OPC, especially in HIV seropositive patients due to aggressive and prolonged use of antifungal agents, therefore, our study emphasizes the need for antifungal drug susceptibility testing whenever antifungal treatment is desired, especially in HIV-infected subjects.

In vitro phagocytosis of several Candida berkhout species by murine leukocytes.

PubMed

Fontenla de Petrino, S E; Bibas Bonet de Jorrat, M E; Sirena, A

1985-03-01

In vitro phagocytosis of thirteen Candida berkhout species by rat leukocytes was studied to assess a possible correlation between pathogenicity and phagocytosis Yeast-leukocyte suspensions were mixed up for 3 h and phagocytic index, germ-tube formation and leukocyte candidacidal activity were evaluated. Highest values for phagocytosis were reached in all cases at the end of the first hour. Leukocyte candidacidal activity was absent. Only C. albicans produced germ-tubes. The various phagocytosis indices were determined depending on the Candida species assayed. Under these conditions, the more pathogenic species presented the lower indices of phagocytosis. It is determined that the in vitro phagocytic index may bear a close relationship with the pathogenicity of the Candida berkhout.

Combinatorial stresses kill pathogenic Candida species

PubMed Central

Kaloriti, Despoina; Tillmann, Anna; Cook, Emily; Jacobsen, Mette; You, Tao; Lenardon, Megan; Ames, Lauren; Barahona, Mauricio; Chandrasekaran, Komelapriya; Coghill, George; Goodman, Daniel; Gow, Neil A. R.; Grebogi, Celso; Ho, Hsueh-Lui; Ingram, Piers; McDonagh, Andrew; De Moura, Alessandro P. S.; Pang, Wei; Puttnam, Melanie; Radmaneshfar, Elahe; Romano, Maria Carmen; Silk, Daniel; Stark, Jaroslav; Stumpf, Michael; Thiel, Marco; Thorne, Thomas; Usher, Jane; Yin, Zhikang; Haynes, Ken; Brown, Alistair J. P.

2012-01-01

Pathogenic microbes exist in dynamic niches and have evolved robust adaptive responses to promote survival in their hosts. The major fungal pathogens of humans, Candida albicans and Candida glabrata, are exposed to a range of environmental stresses in their hosts including osmotic, oxidative and nitrosative stresses. Significant efforts have been devoted to the characterization of the adaptive responses to each of these stresses. In the wild, cells are frequently exposed simultaneously to combinations of these stresses and yet the effects of such combinatorial stresses have not been explored. We have developed a common experimental platform to facilitate the comparison of combinatorial stress responses in C. glabrata and C. albicans. This platform is based on the growth of cells in buffered rich medium at 30°C, and was used to define relatively low, medium and high doses of osmotic (NaCl), oxidative (H 2O2) and nitrosative stresses (e.g., dipropylenetriamine (DPTA)-NONOate). The effects of combinatorial stresses were compared with the corresponding individual stresses under these growth conditions. We show for the first time that certain combinations of combinatorial stress are especially potent in terms of their ability to kill C. albicans and C. glabrata and/or inhibit their growth. This was the case for combinations of osmotic plus oxidative stress and for oxidative plus nitrosative stress. We predict that combinatorial stresses may be highly signif cant in host defences against these pathogenic yeasts. PMID:22463109

The Candida Pathogenic Species Complex

PubMed Central

Turner, Siobhán A.; Butler, Geraldine

2014-01-01

Candida species are the most common causes of fungal infection. Approximately 90% of infections are caused by five species: Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis, and Candida krusei. Three (C. albicans, C. tropicalis, and C. parapsilosis) belong to the CTG clade, in which the CTG codon is translated as serine and not leucine. C. albicans remains the most commonly isolated but is decreasing relative to the other species. The increasing incidence of C. glabrata is related to its reduced susceptibility to azole drugs. Genome analysis suggests that virulence in the CTG clade is associated with expansion of gene families, particularly of cell wall genes. Similar independent processes took place in the C. glabrata species group. Gene loss and expansion in an ancestor of C. glabrata may have resulted in preadaptations that enabled pathogenicity. PMID:25183855

An Efficient, Rapid, and Recyclable System for CRISPR-Mediated Genome Editing in Candida albicans.

PubMed

Nguyen, Namkha; Quail, Morgan M F; Hernday, Aaron D

2017-01-01

Candida albicans is the most common fungal pathogen of humans. Historically, molecular genetic analysis of this important pathogen has been hampered by the lack of stable plasmids or meiotic cell division, limited selectable markers, and inefficient methods for generating gene knockouts. The recent development of clustered regularly interspaced short palindromic repeat(s) (CRISPR)-based tools for use with C. albicans has opened the door to more efficient genome editing; however, previously reported systems have specific limitations. We report the development of an optimized CRISPR-based genome editing system for use with C. albicans . Our system is highly efficient, does not require molecular cloning, does not leave permanent markers in the genome, and supports rapid, precise genome editing in C. albicans . We also demonstrate the utility of our system for generating two independent homozygous gene knockouts in a single transformation and present a method for generating homozygous wild-type gene addbacks at the native locus. Furthermore, each step of our protocol is compatible with high-throughput strain engineering approaches, thus opening the door to the generation of a complete C. albicans gene knockout library. IMPORTANCE Candida albicans is the major fungal pathogen of humans and is the subject of intense biomedical and discovery research. Until recently, the pace of research in this field has been hampered by the lack of efficient methods for genome editing. We report the development of a highly efficient and flexible genome editing system for use with C. albicans . This system improves upon previously published C. albicans CRISPR systems and enables rapid, precise genome editing without the use of permanent markers. This new tool kit promises to expedite the pace of research on this important fungal pathogen.

Translocation of cell-penetrating peptides into Candida fungal pathogens.

PubMed

Gong, Zifan; Karlsson, Amy J

2017-09-01

Cell-penetrating peptides (CPPs) are small peptides capable of crossing cellular membranes while carrying molecular cargo. Although they have been widely studied for their ability to translocate nucleic acids, small molecules, and proteins into mammalian cells, studies of their interaction with fungal cells are limited. In this work, we evaluated the translocation of eleven fluorescently labeled peptides into the important human fungal pathogens Candida albicans and C. glabrata and explored the mechanisms of translocation. Seven of these peptides (cecropin B, penetratin, pVEC, MAP, SynB, (KFF) 3 K, and MPG) exhibited substantial translocation (>80% of cells) into both species in a concentration-dependent manner, and an additional peptide (TP-10) exhibiting strong translocation into only C. glabrata. Vacuoles were involved in translocation and intracellular trafficking of the peptides in the fungal cells and, for some peptides, escape from the vacuoles and localization in the cytosol were correlated to toxicity toward the fungal cells. Endocytosis was involved in the translocation of cecropin B, MAP, SynB, MPG, (KFF) 3 K, and TP-10, and cecropin B, penetratin, pVEC, and MAP caused membrane permeabilization during translocation. These results indicate the involvement of multiple translocation mechanisms for some CPPs. Although high levels of translocation were typically associated with toxicity of the peptides toward the fungal cells, SynB was translocated efficiently into Candida cells at concentrations that led to minimal toxicity. Our work highlights the potential of CPPs in delivering antifungal molecules and other bioactive cargo to Candida pathogens. © 2017 The Protein Society.

Mycological examinations on the fungal flora of the chicken comb.

PubMed

Gründer, S; Mayser, P; Redmann, T; Kaleta, E F

2005-03-01

A total of 500 combs of adult chickens from two different locations in Germany (Hessen and Schleswig-Holstein) were clinically and mycologically examined. The chickens came from three battery cages (n = 79), one voliere system (n=32), six flocks maintained on deep litter (n = 69) and 12 flocks kept on free outdoor range (n=320). Twenty-two of the 500 chicken combs (4.4%) were found to have clinical signs: only non-specific lesions neither typical of mycosis nor of avian pox such as desquamation with crust formation, yellow to brown or black dyschromic changes, alopecia in the surrounding area and moist inflammation. Only seven of the 22 clinically altered combs showed a positive mycological result; the non-pathogenic and geophilic Trichophyton terrestre in one case and non-pathogenic yeast in six cases. The following fungi were seen in the different housing systems: 13 dermatophytes (2.6% of 500 samples): 12 x T. terrestre, 1 x Trichophyton mentagrophytes, 11 isolates of Chrysosporium georgiae (2.2% of 500 samples) and 149 isolates of yeasts (29.8%): Malassezia sympodialis: n = 52, Kloeckera apiculata: n = 33, Trichosporon capitatum (syn. Geotrichum capitatum): n = 23, Trichosporon cutaneum/Trichosporon mucoides: n = 12, Trichosporon inkin (syn. Sarcinosporon inkin): n = 8 and Candida spp.: n = 21, including pathogenic or possibly pathogenic species: Candida albicans: n = 3, Candida famata: n = 4, Candida guilliermondii: n = 3, Candida lipolytica: n = 3, Candida dattila: n = 2 and one isolate each of Candida glabrata, Candida parapsilosis, Candida aaseri, Candida catenulata sive brumpti, Candida fructus and Candida kefyr sive pseudotropicalis. There is no stringent correlation between the clinical symptoms diagnosed on the chicken combs and the species of yeasts isolated. The causative agent of favus in chickens, Trichophyton gallinae, and the saprophytic yeast in pigeons, Cr. neoformans were not isolated. The most frequently isolated yeasts M. sympodialis and Kloeckera apiculata are suggested to be classified as members of the resident flora of the chicken comb.

Identification of virulence determinants of the human pathogenic fungi Aspergillus fumigatus and Candida albicans by proteomics.

PubMed

Kniemeyer, Olaf; Schmidt, André D; Vödisch, Martin; Wartenberg, Dirk; Brakhage, Axel A

2011-06-01

Both fungi Candida albicans and Aspergillus fumigatus can cause a number of life-threatening systemic infections in humans. The commensal yeast C. albicans is one of the main causes of nosocomial fungal infectious diseases, whereas the filamentous fungus A. fumigatus has become one of the most prevalent airborne fungal pathogens. Early diagnosis of these fungal infections is challenging, only a limited number of antifungals for treatment are available, and the molecular details of pathogenicity are hardly understood. The completion of both the A. fumigatus and C. albicans genome sequence provides the opportunity to improve diagnosis, to define new drug targets, to understand the functions of many uncharacterised proteins, and to study protein regulation on a global scale. With the application of proteomic tools, particularly two-dimensional gel electrophoresis and LC/MS-based methods, a comprehensive overview about the proteins of A. fumigatus and C. albicans present or induced during environmental changes and stress conditions has been obtained in the past 5 years. However, for the discovery of further putative virulence determinants, more sensitive and targeted proteomic methods have to be applied. Here, we review the recent proteome data generated for A. fumigatus and C. albicans that are related to factors required for pathogenicity. Copyright © 2011 Elsevier GmbH. All rights reserved.

Intestinal colonization with Candida albicans and mucosal immunity

PubMed Central

Bai, Xiao-Dong; Liu, Xian-Hua; Tong, Qing-Ying

2004-01-01

AIM: To observe the relationship between intestinal lumen colonization with Candida albicans and mucosal secretory IgA (sIgA). METHODS: A total of 82 specific-pathogen-free mice were divided randomly into control and colonization groups. After Candida albicans were inoculated into specific-pathogen-free mice, the number of Candida albicans adhering to cecum and mucosal membrane was counted. The lymphocyte proliferation in Peyer’s patch and in lamina propria was shown by BrdU incorporation, while mucosal sIgA (surface membrane) isotype switch in Peyer’s patch was investigated. IgA plasma cells in lamina propria were observed by immunohistochemical staining. Specific IgA antibodies to Candida albicans were measured with ELISA. RESULTS: From d 3 to d 14 after Candida albicans gavaging to mice, the number of Candida albicans colonizing in lumen and adhering to mucosal membrane was sharply reduced. Candida albicans translocation to mesenteric lymph nodes occurred at early time points following gavage administration and disappeared at later time points. Meanwhile, the content of specific IgA was increased obviously. Proliferation and differentiation of lymphocytes in lamina propria were also increased. CONCLUSION: Lymphocytes in lamina propria play an important role in intestinal mucosal immunity of specific-pathogen-free mice when they are first inoculated with Candida albicans. The decreasing number of Candida albicans in intestine is related to the increased level of specific IgA antibodies in the intestinal mucus. PMID:15237449

Oral Candida albicans isolates from HIV-positive individuals have similar in vitro biofilm-forming ability and pathogenicity as invasive Candida isolates

PubMed Central

2011-01-01

Background Candida can cause mucocutaneous and/or systemic infections in hospitalized and immunosuppressed patients. Most individuals are colonized by Candida spp. as part of the oral flora and the intestinal tract. We compared oral and systemic isolates for the capacity to form biofilm in an in vitro biofilm model and pathogenicity in the Galleria mellonella infection model. The oral Candida strains were isolated from the HIV patients and included species of C. albicans, C. glabrata, C. tropicalis, C. parapsilosis, C. krusei, C. norvegensis, and C. dubliniensis. The systemic strains were isolated from patients with invasive candidiasis and included species of C. albicans, C. glabrata, C. tropicalis, C. parapsilosis, C. lusitaniae, and C. kefyr. For each of the acquired strains, biofilm formation was evaluated on standardized samples of silicone pads and acrylic resin. We assessed the pathogenicity of the strains by infecting G. mellonella animals with Candida strains and observing survival. Results The biofilm formation and pathogenicity in Galleria was similar between oral and systemic isolates. The quantity of biofilm formed and the virulence in G. mellonella were different for each of the species studied. On silicone pads, C. albicans and C. dubliniensis produced more biofilm (1.12 to 6.61 mg) than the other species (0.25 to 3.66 mg). However, all Candida species produced a similar biofilm on acrylic resin, material used in dental prostheses. C. albicans, C. dubliniensis, C. tropicalis, and C. parapsilosis were the most virulent species in G. mellonella with 100% of mortality, followed by C. lusitaniae (87%), C. novergensis (37%), C. krusei (25%), C. glabrata (20%), and C. kefyr (12%). Conclusions We found that on silicone pads as well as in the Galleria model, biofilm formation and virulence depends on the Candida species. Importantly, for C. albicans the pathogenicity of oral Candida isolates was similar to systemic Candida isolates, suggesting that Candida isolates have similar biofilm-forming ability and virulence regardless of the infection site from which it was isolated. PMID:22053894

Sexual reproduction and the evolution of microbial pathogens.

PubMed

Heitman, Joseph

2006-09-05

Three common systemic human fungal pathogens--Cryptococcus neoformans, Candida albicans and Aspergillus fumigatus--have retained all the machinery to engage in sexual reproduction, and yet their populations are often clonal with limited evidence for recombination. Striking parallels have emerged with four protozoan parasites that infect humans: Toxoplasma gondii, Trypanosoma brucei, Trypanosoma cruzi and Plasmodium falciparum. Limiting sexual reproduction appears to be a common virulence strategy, enabling generation of clonal populations well adapted to host and environmental niches, yet retaining the ability to engage in sexual or parasexual reproduction and respond to selective pressure. Continued investigation of the sexual nature of microbial pathogens should facilitate both laboratory investigation and an understanding of the complex interplay between pathogens, hosts, vectors, and their environments.

A surprisingly large RNase P RNA in Candida glabrata

PubMed Central

KACHOURI, RYM; STRIBINSKIS, VILIUS; ZHU, YANGLONG; RAMOS, KENNETH S.; WESTHOF, ERIC; LI, YONG

2005-01-01

We have found an extremely large ribonuclease P (RNase P) RNA (RPR1) in the human pathogen Candida glabrata and verified that this molecule is expressed and present in the active enzyme complex of this hemiascomycete yeast. A structural alignment of the C. glabrata sequence with 36 other hemiascomycete RNase P RNAs (abbreviated as P RNAs) allows us to characterize the types of insertions. In addition, 15 P RNA sequences were newly characterized by searching in the recently sequenced genomes Candida albicans, C. glabrata, Debaryomyces hansenii, Eremothecium gossypii, Kluyveromyces lactis, Kluyveromyces waltii, Naumovia castellii, Saccharomyces kudriavzevii, Saccharomyces mikatae, and Yarrowia lipolytica; and by PCR amplification for other Candida species (Candida guilliermondii, Candida krusei, Candida parapsilosis, Candida stellatoidea, and Candida tropicalis). The phylogenetic comparative analysis identifies a hemiascomycete secondary structure consensus that presents a conserved core in all species with variable insertions or deletions. The most significant variability is found in C. glabrata P RNA in which three insertions exceeding in total 700 nt are present in the Specificity domain. This P RNA is more than twice the length of any other homologous P RNAs known in the three domains of life and is eight times the size of the smallest. RNase P RNA, therefore, represents one of the most diversified noncoding RNAs in terms of size variation and structural diversity. PMID:15987816

Plasma membrane organization promotes virulence of the human fungal pathogen Candida albicans

PubMed Central

Douglas, Lois M.; Konopka, James. B.

2017-01-01

Candida albicans is a human fungal pathogen capable of causing lethal systemic infections. The plasma membrane plays key roles in virulence because it not only functions as a protective barrier, it also mediates dynamic functions including secretion of virulence factors, cell wall synthesis, invasive hyphal morphogenesis, endocytosis, and nutrient uptake. Consistent with this functional complexity, the plasma membrane is composed of a wide array of lipids and proteins. These components are organized into distinct domains that will be the topic of this review. Some of the plasma membrane domains that will be described are known to act as scaffolds or barriers to diffusion, such as MCC/eisosomes, septins, and sites of contact with the endoplasmic reticulum. Other zones mediate dynamic processes, including secretion, endocytosis, and a special region at hyphal tips that facilitates rapid growth. The highly organized architecture of the plasma membrane facilitates the coordination of diverse functions and promotes the pathogenesis of C. albicans. PMID:26920878

Plasma membrane organization promotes virulence of the human fungal pathogen Candida albicans.

PubMed

Douglas, Lois M; Konopka, James B

2016-03-01

Candida albicans is a human fungal pathogen capable of causing lethal systemic infections. The plasma membrane plays key roles in virulence because it not only functions as a protective barrier, it also mediates dynamic functions including secretion of virulence factors, cell wall synthesis, invasive hyphal morphogenesis, endocytosis, and nutrient uptake. Consistent with this functional complexity, the plasma membrane is composed of a wide array of lipids and proteins. These components are organized into distinct domains that will be the topic of this review. Some of the plasma membrane domains that will be described are known to act as scaffolds or barriers to diffusion, such as MCC/eisosomes, septins, and sites of contact with the endoplasmic reticulum. Other zones mediate dynamic processes, including secretion, endocytosis, and a special region at hyphal tips that facilitates rapid growth. The highly organized architecture of the plasma membrane facilitates the coordination of diverse functions and promotes the pathogenesis of C. albicans.

Candida albicans Chitin Increases Arginase-1 Activity in Human Macrophages, with an Impact on Macrophage Antimicrobial Functions.

PubMed

Wagener, Jeanette; MacCallum, Donna M; Brown, Gordon D; Gow, Neil A R

2017-01-24

The opportunistic human fungal pathogen Candida albicans can cause a variety of diseases, ranging from superficial mucosal infections to life-threatening systemic infections. Phagocytic cells of the innate immune response, such as neutrophils and macrophages, are important first-line responders to an infection and generate reactive oxygen and nitrogen species as part of their protective antimicrobial response. During an infection, host cells generate nitric oxide through the enzyme inducible nitric oxide synthase (iNOS) to kill the invading pathogen. Inside the phagocyte, iNOS competes with the enzyme arginase-1 for a common substrate, the amino acid l-arginine. Several pathogenic species, including bacteria and parasitic protozoans, actively modulate the production of nitric oxide by inducing their own arginases or the host's arginase activity to prevent the conversion of l-arginine to nitric oxide. We report here that C. albicans blocks nitric oxide production in human-monocyte-derived macrophages by induction of host arginase activity. We further determined that purified chitin (a fungal cell wall polysaccharide) and increased chitin exposure at the fungal cell wall surface induces this host arginase activity. Blocking the C. albicans-induced arginase activity with the arginase-specific substrate inhibitor Nω-hydroxy-nor-arginine (nor-NOHA) or the chitinase inhibitor bisdionin F restored nitric oxide production and increased the efficiency of fungal killing. Moreover, we determined that C. albicans influences macrophage polarization from a classically activated phenotype toward an alternatively activated phenotype, thereby reducing antimicrobial functions and mediating fungal survival. Therefore, C. albicans modulates l-arginine metabolism in macrophages during an infection, potentiating its own survival. The availability and metabolism of amino acids are increasingly recognized as crucial regulators of immune functions. In acute infections, the conversion of the "conditionally essential" amino acid l-arginine by the inducible nitric oxide synthase to nitric oxide is a resistance factor that is produced by the host to fight pathogens. Manipulation of these host defense mechanisms by the pathogen can be key to successful host invasion. We show here that the human opportunistic fungal pathogen Candida albicans influences l-arginine availability for nitric oxide production by induction of the substrate-competing host enzyme arginase-1. This led to a reduced production of nitric oxide and, moreover, reduced eradication of the fungus by human macrophages. We demonstrate that blocking of host arginase-1 activity restored nitric oxide production and increased the killing potential of macrophages. These results highlight the therapeutic potential of l-arginine metabolism in fungal diseases. Copyright © 2017 Wagener et al.

Integrated inference and evaluation of host–fungi interaction networks

PubMed Central

Remmele, Christian W.; Luther, Christian H.; Balkenhol, Johannes; Dandekar, Thomas; Müller, Tobias; Dittrich, Marcus T.

2015-01-01

Fungal microorganisms frequently lead to life-threatening infections. Within this group of pathogens, the commensal Candida albicans and the filamentous fungus Aspergillus fumigatus are by far the most important causes of invasive mycoses in Europe. A key capability for host invasion and immune response evasion are specific molecular interactions between the fungal pathogen and its human host. Experimentally validated knowledge about these crucial interactions is rare in literature and even specialized host–pathogen databases mainly focus on bacterial and viral interactions whereas information on fungi is still sparse. To establish large-scale host–fungi interaction networks on a systems biology scale, we develop an extended inference approach based on protein orthology and data on gene functions. Using human and yeast intraspecies networks as template, we derive a large network of pathogen–host interactions (PHI). Rigorous filtering and refinement steps based on cellular localization and pathogenicity information of predicted interactors yield a primary scaffold of fungi–human and fungi–mouse interaction networks. Specific enrichment of known pathogenicity-relevant genes indicates the biological relevance of the predicted PHI. A detailed inspection of functionally relevant subnetworks reveals novel host–fungal interaction candidates such as the Candida virulence factor PLB1 and the anti-fungal host protein APP. Our results demonstrate the applicability of interolog-based prediction methods for host–fungi interactions and underline the importance of filtering and refinement steps to attain biologically more relevant interactions. This integrated network framework can serve as a basis for future analyses of high-throughput host–fungi transcriptome and proteome data. PMID:26300851

Disarming Fungal Pathogens: Bacillus safensis Inhibits Virulence Factor Production and Biofilm Formation by Cryptococcus neoformans and Candida albicans

PubMed Central

2017-01-01

ABSTRACT Bacteria interact with each other in nature and often compete for limited nutrient and space resources. However, it is largely unknown whether and how bacteria also interact with human fungal pathogens naturally found in the environment. Here, we identified a soil bacterium, Bacillus safensis, which potently blocked several key Cryptococcus neoformans virulence factors, including formation of the antioxidant pigment melanin and production of the antiphagocytic polysaccharide capsule. The bacterium also inhibited de novo cryptococcal biofilm formation but had only modest inhibitory effects on already formed biofilms or planktonic cell growth. The inhibition of fungal melanization was dependent on direct cell contact and live bacteria. B. safensis also had anti-virulence factor activity against another major human-associated fungal pathogen, Candida albicans. Specifically, dual-species interaction studies revealed that the bacterium strongly inhibited C. albicans filamentation and biofilm formation. In particular, B. safensis physically attached to and degraded candidal filaments. Through genetic and phenotypic analyses, we demonstrated that bacterial chitinase activity against fungal cell wall chitin is a factor contributing to the antipathogen effect of B. safensis. PMID:28974618

Candida glabrata Biofilms: How Far Have We Come?

PubMed Central

Rodrigues, Célia F.; Rodrigues, Maria Elisa; Silva, Sónia; Henriques, Mariana

2017-01-01

Infections caused by Candida species have been increasing in the last decades and can result in local or systemic infections, with high morbidity and mortality. After Candida albicans, Candida glabrata is one of the most prevalent pathogenic fungi in humans. In addition to the high antifungal drugs resistance and inability to form hyphae or secret hydrolases, C. glabrata retain many virulence factors that contribute to its extreme aggressiveness and result in a low therapeutic response and serious recurrent candidiasis, particularly biofilm formation ability. For their extraordinary organization, especially regarding the complex structure of the matrix, biofilms are very resistant to antifungal treatments. Thus, new approaches to the treatment of C. glabrata’s biofilms are emerging. In this article, the knowledge available on C. glabrata’s resistance will be highlighted, with a special focus on biofilms, as well as new therapeutic alternatives to control them. PMID:29371530

Inhibition of Candida albicans biofilm by pure selenium nanoparticles synthesized by pulsed laser ablation in liquids.

PubMed

Guisbiers, Grégory; Lara, Humberto H; Mendoza-Cruz, Ruben; Naranjo, Guillermo; Vincent, Brandy A; Peralta, Xomalin G; Nash, Kelly L

2017-04-01

Selenoproteins play an important role in the human body by accomplishing essential biological functions like oxido-reductions, antioxidant defense, thyroid hormone metabolism and immune response; therefore, the possibility to synthesize selenium nanoparticles free of any contaminants is exciting for future nano-medical applications. This paper reports the first synthesis of selenium nanoparticles by femtosecond pulsed laser ablation in de-ionized water. Those pure nanoparticles have been successfully used to inhibit the formation of Candida albicans biofilms. Advanced electron microscopy images showed that selenium nanoparticles easily adhere on the biofilm, then penetrate into the pathogen, and consequently damage the cell structure by substituting with sulfur. 50% inhibition of Candida albicans biofilm was obtained at only 25 ppm. Finally, the two physical parameters proved to affect strongly the viability of Candida albicans are the crystallinity and particle size. Copyright © 2016 Elsevier Inc. All rights reserved.

In vitro antifungal activity of different components of Centratherum anthelminticum and Ocimum sanctum seed oils and their synergism against oral pathogenic fungi

PubMed Central

H Gopalkrishna, Aparna; M, Seshagiri; Muddaiah, Sunil; R, Shashidara

2016-01-01

Background. Opportunistic fungal infections like candidiasis are common in the oral cavity. In recent years Candida species have shown resistance against a number of synthetic drugs. This study assessed the antifungal activity of Centratherum anthelminticum and Ocimum sanctum seed oils against six common pathogenic Candida strains. Synergistic activity of the major oil components was also studied. Methods. Antifungal activity of Centratherum anthelminticum and Ocimum sanctum seed oils were tested against six oral fungal pathogens, Candida albicans ATCC 90028, Candida krusei 6258, Candida tropicalis 13803, Candida parapsilosis22019, Candida glabrata 90030 and Candida dubliniensis MYA 646, by disc diffusion and broth microdilution methods to determine the diameter of inhibition zone (DIZ) and minimum inhibitory concentration (MIC), respectively. The oil was extracted using Soxhlet apparatus from seeds subjected to columnchromatography (CC) and thin layer chromatography (TLC) and major components were separated and quantified. Results. All the six Candida strains showed growth inhibition to a variable degree when tested with both seed oils. Both seed oils showed antifungal activity. For Centratherum anthelminticum seed oil maximum DIZ at 7 μL was recorded at 75.7 mm for Candida albicans ATCC 90028, and the least DIZ was 45.7 mm for Candida dubliniensis MYA 646. For Ocimum sanctum seed oil maximum DIZ at 7 μL was 61.0 mm for Candida krusei ATCC 6258 and the least DIZ was 46.7 mm for Candida tropicalis ATCC 13803. The mixtures of phospholipids and unsaponifiable matter exhibitedMIC values at 1.25 μL for both oils, whereas neutral lipids fraction and unsaponifiable matter exhibited similar MIC at 2.5 μL against Candida albicans and Candida krusei. Conclusion.Centratherum anthelminticum and Ocimum sanctumseed oils exhibited strong antifungal activity against six different species of Candida and this may be attributed to various active components in the oil and their synergistic activity. PMID:27429725

Dill (Anethum graveolens L.) seed essential oil induces Candida albicans apoptosis in a metacaspase-dependent manner.

PubMed

Chen, Yuxin; Zeng, Hong; Tian, Jun; Ban, Xiaoquan; Ma, Bingxin; Wang, Youwei

2014-04-01

Dill (Anethum graveolens L.) has been used in traditional Uighur medicine for its various pharmacological activities. Previous studies have suggested that dill seed essential oil (DSEO) has anti-Candida potential and the mechanism of its action also has been studied. Our study examined whether DSEO induces apoptosis in the human pathogen Candida albicans ATCC 64550. Our results indicate that C. albicans ATCC 64550 cells treated with DSEO show some typical apoptosis characters, such as decrease in adenosine triphosphatase (ATPase) activity, chromatin condensation, nuclear fragmentation, and phosphatidylserine (PS) exposure. The DSEO promoted cytochrome c (cyt c) release and metacaspase activation, which resulted in C. albicans ATCC 64550 apoptosis. L-cysteine prevented the DSEO-induced nuclear fragmentation, PS externalization, and metacaspase activation, thus indicating that the reactive oxygen species (ROS) is an important mediator of DSEO-induced apoptosis. To our knowledge, this study is the first to report the induction of apoptosis of this pathogen with concomitant metacaspase activation by DSEO. Copyright © 2014 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

A potential plant-derived antifungal acetylenic acid mediates its activity by interfering with fatty acid homeostasis

USDA-ARS?s Scientific Manuscript database

6-Nonadecynoic acid (6-NDA), a plant-derived acetylenic acid, exhibits strong inhibitory activity against the human fungal pathogens Candida albicans, Aspergillus fumigatus, and Trichophyton mentagrophytes. In the present study, transcriptional profiling coupled with mutant and biochemical analyses...

Soybean toxin (SBTX), a protein from soybeans that inhibits the life cycle of plant and human pathogenic fungi.

PubMed

Morais, Janne Keila S; Gomes, Valdirene M; Oliveira, José Tadeu A; Santos, Izabela S; Da Cunha, Maura; Oliveira, Hermogenes D; Oliveira, Henrique P; Sousa, Daniele O B; Vasconcelos, Ilka M

2010-10-13

Soybean toxin (SBTX) is a 44 kDa glycoprotein that is lethal to mice (LD(50) = 5.6 mg/kg). This study reports the toxicity of SBTX on pathogenic fungi and yeasts and the mechanism of its action. SBTX inhibited spore germination of Aspergillus niger and Penicillium herguei and was toxic to Candida albicans, Candida parapsilosis, Kluyveromyces marxiannus , Pichia membranifaciens, and Saccharomyces cerevisiae. In addition, SBTX hampered the growth of C. albicans and K. marxiannus and inhibited the glucose-stimulated acidification of the incubation medium by S. cerevisiae, suggesting that SBTX interferes with intracellular proton transport to the external medium. Moreover, SBTX caused cell-wall disruption, condensation/shrinkage of cytosol, pseudohyphae formation, and P. membranifaciens and C. parapsilosis cell death. SBTX is toxic to fungi at concentrations far below the dose lethal to mice and has potential in the design of new antifungal drugs or in the development of transgenic crops resistant to pathogens.

Beyond Candida albicans: Mechanisms of immunity to non-albicans Candida species

PubMed Central

Whibley, Natasha; Gaffen, Sarah L.

2015-01-01

The fungal genus Candida encompasses numerous species that inhabit a variety of hosts, either as commensal microbes and/or pathogens. Candida species are a major cause of fungal infections, yet to date there are no vaccines against Candida or indeed any other fungal pathogen. Our knowledge of immunity to Candida mainly comes from studies on C. albicans, the most frequent species associated with disease. However, non-albicans Candida (NAC) species also cause disease and their prevalence is increasing. Although research into immunity to NAC species is still at an early stage, it is becoming apparent that immunity to C. albicans differs in important ways from non-albicans species, with important implications for treatment, therapy and predicted demographic susceptibility. This review will discuss the current understanding of immunity to NAC species in the context of immunity to C. albicans, and highlight as-yet unanswered questions. PMID:26276374

Unexpected effects of azole transporter inhibitors on antifungal susceptibility in Candida glabrata and other pathogenic Candida species

PubMed Central

Nagayoshi, Yohsuke; Shimamura, Shintaro; Nakayama, Hironobu; Minematsu, Asuka; Yamauchi, Shunsuke; Takazono, Takahiro; Nakamura, Shigeki; Yanagihara, Katsunori; Kohno, Shigeru; Mukae, Hiroshi; Izumikawa, Koichi

2017-01-01

The pathogenic fungus Candida glabrata is often resistant to azole antifungal agents. Drug efflux through azole transporters, such as Cdr1 and Cdr2, is a key mechanism of azole resistance and these genes are under the control of the transcription factor Pdr1. Recently, the monoamine oxidase A (MAO-A) inhibitor clorgyline was shown to inhibit the azole efflux pumps, leading to increased azole susceptibility in C. glabrata. In the present study, we have evaluated the effects of clorgyline on susceptibility of C. glabrata to not only azoles, but also to micafungin and amphotericin B, using wild-type and several mutant strains. The addition of clorgyline to the culture media increased fluconazole susceptibility of a C. glabrata wild-type strain, whereas micafungin and amphotericin B susceptibilities were markedly decreased. These phenomena were also observed in other medically important Candida species, including Candida albicans, Candida parapsilosis, Candida tropicalis, and Candida krusei. Expression levels of CDR1, CDR2 and PDR1 mRNAs and an amount of Cdr1 protein in the C. glabrata wild-type strain were highly increased in response to the treatment with clorgyline. However, loss of Cdr1, Cdr2, Pdr1, and a putative clorgyline target (Fms1), which is an ortholog of human MAO-A, or overexpression of CDR1 did not affect the decreased susceptibility to micafungin and amphotericin B in the presence of clorgyline. The presence of other azole efflux pump inhibitors including milbemycin A4 oxime and carbonyl cyanide 3-chlorophenylhydrazone also decreased micafungin susceptibility in C. glabrata wild-type, Δcdr1, Δcdr2, and Δpdr1 strains. These findings suggest that azole efflux pump inhibitors increase azole susceptibility but concurrently induce decreased susceptibility to other classes of antifungals independent of azole transporter functions. PMID:28700656

Unexpected effects of azole transporter inhibitors on antifungal susceptibility in Candida glabrata and other pathogenic Candida species.

PubMed

Nagayoshi, Yohsuke; Miyazaki, Taiga; Shimamura, Shintaro; Nakayama, Hironobu; Minematsu, Asuka; Yamauchi, Shunsuke; Takazono, Takahiro; Nakamura, Shigeki; Yanagihara, Katsunori; Kohno, Shigeru; Mukae, Hiroshi; Izumikawa, Koichi

2017-01-01

The pathogenic fungus Candida glabrata is often resistant to azole antifungal agents. Drug efflux through azole transporters, such as Cdr1 and Cdr2, is a key mechanism of azole resistance and these genes are under the control of the transcription factor Pdr1. Recently, the monoamine oxidase A (MAO-A) inhibitor clorgyline was shown to inhibit the azole efflux pumps, leading to increased azole susceptibility in C. glabrata. In the present study, we have evaluated the effects of clorgyline on susceptibility of C. glabrata to not only azoles, but also to micafungin and amphotericin B, using wild-type and several mutant strains. The addition of clorgyline to the culture media increased fluconazole susceptibility of a C. glabrata wild-type strain, whereas micafungin and amphotericin B susceptibilities were markedly decreased. These phenomena were also observed in other medically important Candida species, including Candida albicans, Candida parapsilosis, Candida tropicalis, and Candida krusei. Expression levels of CDR1, CDR2 and PDR1 mRNAs and an amount of Cdr1 protein in the C. glabrata wild-type strain were highly increased in response to the treatment with clorgyline. However, loss of Cdr1, Cdr2, Pdr1, and a putative clorgyline target (Fms1), which is an ortholog of human MAO-A, or overexpression of CDR1 did not affect the decreased susceptibility to micafungin and amphotericin B in the presence of clorgyline. The presence of other azole efflux pump inhibitors including milbemycin A4 oxime and carbonyl cyanide 3-chlorophenylhydrazone also decreased micafungin susceptibility in C. glabrata wild-type, Δcdr1, Δcdr2, and Δpdr1 strains. These findings suggest that azole efflux pump inhibitors increase azole susceptibility but concurrently induce decreased susceptibility to other classes of antifungals independent of azole transporter functions.

Dynamics of Mixed- Candida Species Biofilms in Response to Antifungals.

PubMed

Vipulanandan, G; Herrera, M; Wiederhold, N P; Li, X; Mintz, J; Wickes, B L; Kadosh, D

2018-01-01

Oral infections caused by Candida species, the most commonly isolated human fungal pathogen, are frequently associated with biofilms. Although Candida albicans is the predominant organism found in patients with oral thrush, a biofilm infection, there is an increasing incidence of oral colonization and infections caused by non- albicans Candida species, including C. glabrata, C. dubliniensis, and C. tropicalis, which are frequently more resistant to antifungal treatment. While single-species Candida biofilms have been well studied, considerably less is known about the dynamics of mixed- Candida species biofilms and how these dynamics are altered by antifungal treatment. To address these questions, we developed a quantitative polymerase chain reaction-based approach to determine the precise species composition of mixed- Candida species biofilms formed by clinical isolates and laboratory strains in the presence and absence of clinically relevant concentrations of 3 commonly used antifungals: fluconazole, caspofungin, and amphotericin B. In monospecies biofilms, fluconazole exposure favored growth of C. glabrata and C. tropicalis, while caspofungin generally favored significant growth of all species to a varying degree. Fluconazole was not effective against preformed mixed- Candida species biofilms while amphotericin B was potent. As a general trend, in mixed- Candida species biofilms, C. albicans lost dominance in the presence of antifungals. Interestingly, presence in mixed versus monospecies biofilms reduced susceptibility to amphotericin B for C. tropicalis and C. glabrata. Overall, our data suggest that antifungal treatment favors the growth of specific non- albicans Candida species in mixed- Candida species biofilms.

Hyphal Growth in Human Fungal Pathogens and Its Role in Virulence

PubMed Central

Brand, Alexandra

2012-01-01

Most of the fungal species that infect humans can grow in more than one morphological form but only a subset of pathogens produce filamentous hyphae during the infection process. This subset is phylogenetically unrelated and includes the commonly carried yeasts, Candida albicans, C. dubliniensis, and Malassezia spp., and the acquired pathogens, Aspergillus fumigatus and dermatophytes such as Trichophyton rubrum and T. mentagrophytes. The primary function of hypha formation in these opportunistic pathogens is to invade the substrate they are adhered to, whether biotic or abiotic, but other functions include the directional translocation between host environments, consolidation of the colony, nutrient acquisition and the formation of 3-dimensional matrices. To support these functions, polarised hyphal growth is co-regulated with other factors that are essential for normal hypha function in vivo. PMID:22121367

New secondary metabolites from bioactive extracts of the fungus Armillaria tabescens

Treesearch

H. M. T.Bandara Herath; Melissa Jacob; A. Alpus Wilson; Hamed K. Abbas; N.P. Dhammika Nanayakkara Nanayakkara

2012-01-01

Ethyl acetate extracts of Armillaria tabescens (strain JNB-OZ344) showed significant fungistatic and bacteristatic activities against several major human pathogens including Candida albicans, Cryptococcus neoformans, Escherichia coli and Mycobacterium intracellulare. Chemical analysis of these extracts led to the isolation and identification of four new compounds,...

Specific Human and Candida Cellular Interactions Lead to Controlled or Persistent Infection Outcomes during Granuloma-Like Formation.

PubMed

Misme-Aucouturier, Barbara; Albassier, Marjorie; Alvarez-Rueda, Nidia; Le Pape, Patrice

2017-01-01

A delayed type of multicellular process could be crucial during chronic candidiasis in determining the course of infection. This reaction, consisting of organized immune cells surrounding the pathogen, initiates an inflammatory response to avoid fungal dissemination. The goal of the present study was to examine, at an in vitro cellular scale, Candida and human immune cell interaction dynamics during a long-term period. By challenging human peripheral blood immune cells from 10 healthy donors with 32 Candida albicans and non-albicans (C. glabrata, C. tropicalis, C. parapsilosis, C. dubliniensis, C. lusitaniae, C. krusei, and C. kefyr) clinical isolates, we showed that Candida spp. induced the formation of granuloma-like structures within 6 days after challenge, but their sizes and the respective fungal burdens differed according to the Candida species. These two parameters are positively correlated. Phenotypic characteristics, such as hypha formation and higher axenic growth rate, seem to contribute to yeast persistence within granuloma-like structures. We showed an interindividual variability of the human response against Candida spp. Higher proportions of neutrophils and elevated CD4 + /CD8 + T cell ratios during the first days after challenge were correlated with early production of gamma interferon (IFN-γ) and associated with controlled infection. In contrast, the persistence of Candida could result from upregulation of proinflammatory cytokines such as interleukin-6 (IL-6), IFN-γ, and tumor necrosis factor alpha (TNF-α) and a poor anti-inflammatory negative feedback (IL-10). Importantly, regulatory subsets of NK cells and CD4 lo CD8 hi doubly positive (DP) lymphocytes at late stage infiltrate granuloma-like structures and could correlate with the IL-10 and TNF-α production. These data offer a base frame to explain cellular events that guide infection control or fungal persistence. Copyright © 2016 Misme-Aucouturier et al.

A Novel Hybrid Iron Regulation Network Combines Features from Pathogenic and Nonpathogenic Yeasts.

PubMed

Gerwien, Franziska; Safyan, Abu; Wisgott, Stephanie; Hille, Fabrice; Kaemmer, Philipp; Linde, Jörg; Brunke, Sascha; Kasper, Lydia; Hube, Bernhard

2016-10-18

Iron is an essential micronutrient for both pathogens and their hosts, which restrict iron availability during infections in an effort to prevent microbial growth. Successful human pathogens like the yeast Candida glabrata have thus developed effective iron acquisition strategies. Their regulation has been investigated well for some pathogenic fungi and in the model organism Saccharomyces cerevisiae, which employs an evolutionarily derived system. Here, we show that C. glabrata uses a regulation network largely consisting of components of the S. cerevisiae regulon but also of elements of other pathogenic fungi. Specifically, similarly to baker's yeast, Aft1 is the main positive regulator under iron starvation conditions, while Cth2 degrades mRNAs encoding iron-requiring enzymes. However, unlike the case with S. cerevisiae, a Sef1 ortholog is required for full growth under iron limitation conditions, making C. glabrata an evolutionary intermediate to SEF1-dependent fungal pathogens. Therefore, C. glabrata has evolved an iron homeostasis system which seems to be unique within the pathogenic fungi. The fungus Candida glabrata represents an evolutionarily close relative of the well-studied and benign baker's yeast and model organism Saccharomyces cerevisiae On the other hand, C. glabrata is an important opportunistic human pathogen causing both superficial and systemic infections. The ability to acquire trace metals, in particular, iron, and to tightly regulate this process during infection is considered an important virulence attribute of a variety of pathogens. Importantly, S. cerevisiae uses a highly derivative regulatory system distinct from those of other fungi. Until now, the regulatory mechanism of iron homeostasis in C. glabrata has been mostly unknown. Our study revealed a hybrid iron regulation network that is unique to C. glabrata and is placed at an evolutionary midpoint between those of S. cerevisiae and related fungal pathogens. We thereby show that, in the host, even a successful human pathogen can rely largely on a strategy normally found in nonpathogenic fungi from a terrestrial environment. Copyright © 2016 Gerwien et al.

The Novel Candida albicans Transporter Dur31 Is a Multi-Stage Pathogenicity Factor

PubMed Central

Mayer, François L.; Wilson, Duncan; Jacobsen, Ilse D.; Miramón, Pedro; Große, Katharina; Hube, Bernhard

2012-01-01

Candida albicans is the most frequent cause of oral fungal infections. However, the exact pathogenicity mechanisms that this fungus employs are largely unknown and many of the genes expressed during oral infection are uncharacterized. In this study we sought to functionally characterize 12 previously unknown function genes associated with oral candidiasis. We generated homozygous knockout mutants for all 12 genes and analyzed their interaction with human oral epithelium in vitro. Eleven mutants caused significantly less epithelial damage and, of these, deletion of orf19.6656 (DUR31) elicited the strongest reduction in pathogenicity. Interestingly, DUR31 was not only involved in oral epithelial damage, but in multiple stages of candidiasis, including surviving attack by human neutrophils, endothelial damage and virulence in vivo. In silico analysis indicated that DUR31 encodes a sodium/substrate symporter with 13 transmembrane domains and no human homologue. We provide evidence that Dur31 transports histatin 5. This is one of the very first examples of microbial driven import of this highly cytotoxic antimicrobial peptide. Also, in contrast to wild type C. albicans, dur31Δ/Δ was unable to actively increase local environmental pH, suggesting that Dur31 lies in the extracellular alkalinization hyphal auto-induction pathway; and, indeed, DUR31 was required for morphogenesis. In agreement with this observation, dur31Δ/Δ was unable to assimilate the polyamine spermidine. PMID:22438810

[Antimycotic activity in vitro and in vivo of 5-fluorocytosine on pathogenic strains of Candida albicans and Cryptococcus neoformans].

PubMed

Costa, A L; Valenti, A; Costa, G; Calogero, F

1976-01-01

The authors have analyzed the 5 Fluoro Cytosine (5FC) activity on strains of Candida albicans and Criptococcus neoformans, both in vitro and in vivo. In vitro the minimal inhibitory concentration (MIC) was determined; in vivo tests of pathogenicity on rabbit and mouse have been executed. The various findings obtained have shown a strong activity of the 5FC on strains of Candida and Criptococcus.

Sexual Reproduction of Human Fungal Pathogens

PubMed Central

Heitman, Joseph; Carter, Dee A.; Dyer, Paul S.; Soll, David R.

2014-01-01

We review here recent advances in our understanding of sexual reproduction in fungal pathogens that commonly infect humans, including Candida albicans, Cryptococcus neoformans/gattii, and Aspergillus fumigatus. Where appropriate or relevant, we introduce findings on other species associated with human infections. In particular, we focus on rapid advances involving genetic, genomic, and population genetic approaches that have reshaped our view of how fungal pathogens evolve. Rather than being asexual, mitotic, and largely clonal, as was thought to be prevalent as recently as a decade ago, we now appreciate that the vast majority of pathogenic fungi have retained extant sexual, or parasexual, cycles. In some examples, sexual and parasexual unions of pathogenic fungi involve closely related individuals, generating diversity in the population but with more restricted recombination than expected from fertile, sexual, outcrossing and recombining populations. In other cases, species and isolates participate in global outcrossing populations with the capacity for considerable levels of gene flow. These findings illustrate general principles of eukaryotic pathogen emergence with relevance for other fungi, parasitic eukaryotic pathogens, and both unicellular and multicellular eukaryotic organisms. PMID:25085958

EVALUATION OF RAPID, QUANTITATIVE REAL-TIME PCR METHOD FOR ENUMERATION OF PATHOGENIC CANDIDA CELLS IN WATER

EPA Science Inventory

Quantitative Real-Time PCR (QRT-PCR) technology, incorporating fluorigenic 5' nuclease (TaqMan (trademark)) chemistry, was developed for the specific detection and quantification of six pathogenic species of Candida (C. albicans, C. tropicalis, C. krusei, C. parapsilosis, C. glab...

Candida species isolated from different body sites and their antifungal susceptibility pattern: Cross-analysis of Candida albicans and Candida glabrata biofilms.

PubMed

Cataldi, Valentina; Di Campli, Emanuela; Fazii, Paolo; Traini, Tonino; Cellini, Luigina; Di Giulio, Mara

2017-08-01

Candida species are regular commensal in humans, but-especially in immunocompromised patients-they represent opportunistic pathogens giving rise to systemic infection. The aim of the present work was to isolate and characterize for their antifungal profile Candida species from different body sites and to analyze the biofilms produced by C. albicans and C. glabrata isolates. Eighty-one strains of Candida species from 77 patients were identified. Epidemiological study showed that the most isolated species were C. albicans (44), C. glabrata (13) and C. parapsilosis (13) mainly from Hematology, Infectious Diseases, Medicine, Neonatology and Oncology Divisions, the majority of the biological samples were swabs (44) and blood cultures (16). The analysis of the biofilm formation was performed at 24 and 48-hours comparing resistant and susceptible strains of C. albicans to resistant and susceptible strains of C. glabrata. Candida albicans has a greater ability to form biofilm compared to C. glabrata, both in the susceptible and resistant strains reaching maturity after 24 hours with a complex structure composed of blastospores, pseudohyphae, and hyphae embedded in a matrix. On the contrary, C. glabrata biofilm was composed exclusively of blastospores that in the resistant strain, after 24 hours, were organized in a compact multilayer different to the discontinuous structure observed in the susceptible analyzed strains. In conclusion, the increasing of the incidence of Candida species infection together with their emerging drug resistance also related to the biofilm forming capability underline the need to monitor their distribution and susceptibility patterns for improving the surveillance and for a correct management of the infection. © The Author 2016. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Potential Role for a Carbohydrate Moiety in Anti-Candida Activity of Human Oral Epithelial Cells

PubMed Central

Steele, Chad; Leigh, Janet; Swoboda, Rolf; Ozenci, Hatice; Fidel, Paul L.

2001-01-01

Candida albicans is both a commensal and a pathogen at the oral mucosa. Although an intricate network of host defense mechanisms are expected for protection against oropharyngeal candidiasis, anti-Candida host defense mechanisms at the oral mucosa are poorly understood. Our laboratory recently showed that primary epithelial cells from human oral mucosa, as well as an oral epithelial cell line, inhibit the growth of blastoconidia and/or hyphal phases of several Candida species in vitro with a requirement for cell contact and with no demonstrable role for soluble factors. In the present study, we show that oral epithelial cell-mediated anti-Candida activity is resistant to gamma-irradiation and is not mediated by phagocytosis, nitric oxide, hydrogen peroxide, and superoxide oxidative inhibitory pathways or by nonoxidative components such as soluble defensin and calprotectin peptides. In contrast, epithelial cell-mediated anti-Candida activity was sensitive to heat, paraformaldehyde fixation, and detergents, but these treatments were accompanied by a significant loss in epithelial cell viability. Treatments that removed existing membrane protein or lipid moieties in the presence or absence of protein synthesis inhibitors had no effect on epithelial cell inhibitory activity. In contrast, the epithelial cell-mediated anti-Candida activity was abrogated after treatment of the epithelial cells with periodic acid, suggesting a role for carbohydrates. Adherence of C. albicans to oral epithelial cells was unaffected, indicating that the carbohydrate moiety is exclusively associated with the growth inhibition activity. Subsequent studies that evaluated specific membrane carbohydrate moieties, however, showed no role for sulfated polysaccharides, sialic acid residues, or glucose- and mannose-containing carbohydrates. These results suggest that oral epithelial cell-mediated anti-Candida activity occurs exclusively with viable epithelial cells through contact with C. albicans by an as-yet-undefined carbohydrate moiety. PMID:11598085

In Vitro and In Vivo Activity of a Novel Antifungal Small Molecule against Candida Infections

PubMed Central

Yuen, Kwok Yong; Wang, Yu; Yang, Dan; Samaranayake, Lakshman Perera

2014-01-01

Candida is the most common fungal pathogen of humans worldwide and has become a major clinical problem because of the growing number of immunocompromised patients, who are susceptible to infection. Moreover, the number of available antifungals is limited, and antifungal-resistant Candida strains are emerging. New and effective antifungals are therefore urgently needed. Here, we discovered a small molecule with activity against Candida spp. both in vitro and in vivo. We screened a library of 50,240 small molecules for inhibitors of yeast-to-hypha transition, a major virulence attribute of Candida albicans. This screening identified 20 active compounds. Further examination of the in vitro antifungal and anti-biofilm properties of these compounds, using a range of Candida spp., led to the discovery of SM21, a highly potent antifungal molecule (minimum inhibitory concentration (MIC) 0.2 – 1.6 µg/ml). In vitro, SM21 was toxic to fungi but not to various human cell lines or bacterial species and was active against Candida isolates that are resistant to existing antifungal agents. Moreover, SM21 was relatively more effective against biofilms of Candida spp. than the current antifungal agents. In vivo, SM21 prevented the death of mice in a systemic candidiasis model and was also more effective than the common antifungal nystatin at reducing the extent of tongue lesions in a mouse model of oral candidiasis. Propidium iodide uptake assay showed that SM21 affected the integrity of the cell membrane. Taken together, our results indicate that SM21 has the potential to be developed as a novel antifungal agent for clinical use. PMID:24465737

Candida Infections and Human Defensins.

PubMed

Polesello, Vania; Segat, Ludovica; Crovella, Sergio; Zupin, Luisa

2017-01-01

Candida species infections are an important worldwide health issue since they do not only affect immunocompromised patients but also healthy individuals. The host developed different mechanisms of protection against Candida infections; specifically the immune system and the innate immune response are the first line of defence. Defensis are a group of antimicrobial peptides, components of the innate immunity, produced at mucosal level and known to be active against bacteria, virus but also fungi. The aim of the current work was to review all previous studies in literature that analysed defensins in the context of Candida spp. infections, in order to investigate and clarify the exact mechanisms of defensins anti-fungal action. Several studies were identified from 1985 to 2017 (9 works form years 1985 to 1999, 44 works ranging from 2000 to 2009 and 35 from 2010 to 2017) searched in two electronic databases (PubMed and Google Scholar). The main key words used for the research were "Candida", "Defensins"," Innate immune system","fungi". The findings of the reviewed studies highlight the pivotal role of defensins antimicrobial peptides in the immune response against Candida infections, since they are able to discriminate host cell from fungi: defensins are able to recognize the pathogens cell wall (different in composition from the human ones), and to disrupt it through membrane permeabilization. However, further research is needed to explain completely defensins' mechanisms of action to fight C. albicans (and other Candida spp.) infections, being the information fragmentary and only in part elucidated. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Relative Abundances of Candida albicans and Candida glabrata in In Vitro Coculture Biofilms Impact Biofilm Structure and Formation.

PubMed

Olson, Michelle L; Jayaraman, Arul; Kao, Katy C

2018-04-15

Candida is a member of the normal human microbiota and often resides on mucosal surfaces such as the oral cavity or the gastrointestinal tract. In addition to their commensality, Candida species can opportunistically become pathogenic if the host microbiota is disrupted or if the host immune system becomes compromised. An important factor for Candida pathogenesis is its ability to form biofilm communities. The two most medically important species- Candida albicans and Candida glabrata -are often coisolated from infection sites, suggesting the importance of Candida coculture biofilms. In this work, we report that biofilm formation of the coculture population depends on the relative ratio of starting cell concentrations of C. albicans and C. glabrata When using a starting ratio of C. albicans to C. glabrata of 1:3, ∼6.5- and ∼2.5-fold increases in biofilm biomass were observed relative to those of a C. albicans monoculture and a C. albicans / C. glabrata ratio of 1:1, respectively. Confocal microscopy analysis revealed the heterogeneity and complex structures composed of long C. albicans hyphae and C. glabrata cell clusters in the coculture biofilms, and reverse transcription-quantitative PCR (qRT-PCR) studies showed increases in the relative expression of the HWP1 and ALS3 adhesion genes in the C. albicans / C. glabrata 1:3 biofilm compared to that in the C. albicans monoculture biofilm. Additionally, only the 1:3 C. albicans / C. glabrata biofilm demonstrated an increased resistance to the antifungal drug caspofungin. Overall, the results suggest that interspecific interactions between these two fungal pathogens increase biofilm formation and virulence-related gene expression in a coculture composition-dependent manner. IMPORTANCE Candida albicans and Candida glabrata are often coisolated during infection, and the occurrence of coisolation increases with increasing inflammation, suggesting possible synergistic interactions between the two Candida species in pathogenesis. During the course of an infection, the prevalence of each Candida species may change over time due to differences in metabolism and in the resistance of each species to antifungal therapies. Therefore, it is necessary to understand the dynamics between C. albicans and C. glabrata in coculture to develop better therapeutic strategies against Candida infections. Existing in vitro work has focused on understanding how an equal-part culture of C. albicans and C. glabrata impacts biofilm formation and pathogenesis. What is not understood, and what is investigated in this work, is how the composition of Candida species in coculture impacts overall biofilm formation, virulence gene expression, and the therapeutic treatment of biofilms. Copyright © 2018 American Society for Microbiology.

Reclassification of the Candida haemulonii complex as Candida haemulonii (C. haemulonii group I), C. duobushaemulonii sp. nov. (C. haemulonii group II), and C. haemulonii var. vulnera var. nov.: three multiresistant human pathogenic yeasts.

PubMed

Cendejas-Bueno, E; Kolecka, A; Alastruey-Izquierdo, A; Theelen, B; Groenewald, M; Kostrzewa, M; Cuenca-Estrella, M; Gómez-López, A; Boekhout, T

2012-11-01

The Candida haemulonii species complex is currently known as C. haemulonii groups I and II. Here we describe C. haemulonii group II as a new species, Candida duobushaemulonii sp. nov., and C. haemulonii var. vulnera as new a variety of C. haemulonii group I using phenotypic and molecular methods. These taxa and other relatives of C. haemulonii (i.e., Candida auris and Candida pseudohaemulonii) cannot be differentiated by the commercial methods now used for yeast identification. Four isolates (C. haemulonii var. vulnera) differed from the other isolates of C. haemulonii in the sequence of the internal transcribed spacer (ITS) regions of the nuclear rRNA gene operon. The new species and the new variety have a multiresistant antifungal profile, which includes high MICs of amphotericin B (geometric mean MIC, 1.18 mg/liter for C. haemulonii var. vulnera and 2 mg/liter for C. duobushaemulonii sp. nov) and cross-resistance to azole compounds. Identification of these species should be based on molecular methods, such as sequence analysis of ITS regions and matrix-assisted laser desorption ionization-time of flight mass spectrometry.

Sexually transmitted pathogens in pregnant women in a rural South African community.

PubMed Central

O'Farrell, N; Hoosen, A A; Kharsany, A B; van den Ende, J

1989-01-01

One hundred and ninety three consecutive pregnant women attending peripheral antenatal clinics attached to Ngwelezana Hospital, Empangeni, Kwa-Zulu, were examined for evidence of sexually transmitted pathogens. The following incidences were found: Trichomonas vaginalis 49.2% (95), Candida spp 38.3% (74), Chlamydia trachomatis 11.4% (22), Gardnerella vaginalis 6.2% (12), Neisseria gonorrhoeae 5.7% (11), positive syphilis serology results 11.9% (23), hepatitis B surface antigen 4.1% (eight). No woman had antibody to human immunodeficiency virus (HIV). Dyskaryotic smears were found in 20 (10.4%). Human papillomavirus (HPV) was detected cytologically in 11 (5.7%). The range of sexually transmitted pathogens found in this rural community was similar to that found in urban groups studied in South Africa. PMID:2807289

EVALUATION OF A RAPID, QUANTITATIVE REAL-TIME PCR METHOD FOR ENUMERATION OF PATHOGENIC CANDIDA CELLS IN WATER

EPA Science Inventory

Quantitative Real-Time PCR (QRT-PCR) technology, incorporating fluorigenic 5' nuclease (TaqMan?) chemistry, was developed for the specific detection and quantification of six pathogenic species of Candida (C. albicans, C. tropicalis, C. krusei, C. parapsilosis, C. glabrata and C....

Itraconazole-resistant Candida auris with phospholipase, proteinase and hemolysin activity from a case of vulvovaginitis.

PubMed

Kumar, Dharmendra; Banerjee, Tuhina; Pratap, Chandra Bhan; Tilak, Ragini

2015-04-15

Since the emergence of pathogenic non-albicans Candida species, a number of new isolates have been added to the list. One such unusual species is Candida auris (C. auris), recently isolated and studied in few reports. In this study, a case of vulvovaginitis caused by Candida auris incidentally identified by molecular methods using internal transcribed spacer polymerase chain reaction (ITS PCR) is described. Antifungal susceptibility testing revealed the isolate to be resistant to itraconazole (MIC ≥ 2 µg/ml) and expressed important virulence factors including phospholipase, proteinase and hemolysin activity. The patient was successfully treated with oral fluconazole and did not have any invasive fungemia. Very few cases of this emerging pathogen have been reported. However, its isolation from clinical specimens reveals the significance of non-albicans candida species over C. albicans and the diversity of Candida spp causing infections.

Group X hybrid histidine kinase Chk1 is dispensable for stress adaptation, host-pathogen interactions and virulence in the opportunistic yeast Candida guilliermondii.

PubMed

Navarro-Arias, María J; Dementhon, Karine; Defosse, Tatiana A; Foureau, Emilien; Courdavault, Vincent; Clastre, Marc; Le Gal, Solène; Nevez, Gilles; Le Govic, Yohann; Bouchara, Jean-Philippe; Giglioli-Guivarc'h, Nathalie; Noël, Thierry; Mora-Montes, Hector M; Papon, Nicolas

2017-09-01

Hybrid histidine kinases (HHKs) progressively emerge as prominent sensing proteins in the fungal kingdom and as ideal targets for future therapeutics. The group X HHK is of major interest, since it was demonstrated to play an important role in stress adaptation, host-pathogen interactions and virulence in some yeast and mold models, and particularly Chk1, that corresponds to the sole group X HHK in Candida albicans. In the present work, we investigated the role of Chk1 in the low-virulence species Candida guilliermondii, in order to gain insight into putative conservation of the role of group X HHK in opportunistic yeasts. We demonstrated that disruption of the corresponding gene CHK1 does not influence growth, stress tolerance, drug susceptibility, protein glycosylation or cell wall composition in C. guilliermondii. In addition, we showed that loss of CHK1 does not affect C. guilliermondii ability to interact with macrophages and to stimulate cytokine production by human peripheral blood mononuclear cells. Finally, the C. guilliermondii chk1 null mutant was found to be as virulent as the wild-type strain in the experimental model Galleria mellonella. Taken together, our results demonstrate that group X HHK function is not conserved in Candida species. Copyright © 2017 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

New staining methods for yeast like fungi under special consideration of human pathogenic fungi

NASA Astrophysics Data System (ADS)

Paulitsch-Fuchs, Astrid; Treiber, Fritz; Grasser, Erik; Buzina, Walter; Rosker, Christian

2010-11-01

A new method for in-cellular staining of yeast like fungi with Oregon Green and SYTOX Green is presented enabling their detection as well as the observation of cellular details via confocal laser scanning microscopy. Fluorochromes play an important role in many scientific disciplines including medicine, cell biology and botany. For the visualisation of fungal cell walls Calcofluor White is the flourochrome of choice. The necessity of an UV laser for its excitation makes it unpracticable for daily use. Safranin O, DAPI, 2NBDG, Ethidium Bromide and Acridin-orange are commonly used stains for nuclei in fugal microscopy. The attention was given to the possibility of using the differences in staining patterns to distinguish certain pathogenic yeast species e.g. Candida albicans and Candida krusei. Our results show that high quality microscopy of yeast like organisms can readily be achieved by the use of two suitable fluorochromes.

A Novel Strategy to Control and Prevent Norovirus Gastroenteritis

DTIC Science & Technology

2006-11-01

Vibrio cholerae , Candida, etc.) have been reported to recognize the HBGAs as their receptors. NV is the first viral pathogen in the list. Human...and genogroup II: BUDS (AY660568), Grimsby (GrV; AJ004864), Hawaii (HV; U07611), Mexico (MxV; U22498), MOH (AF397156), Parris Island (PiV

[Opportunistic pathogen Candida glabrata and the mechanisms of its resistance to antifungal drugs].

PubMed

Berila, N; Subík, J

2010-04-01

Treatment of not only bacterial but also fungal infections is currently a growing concern. A major reason is the acquisition of multidrug resistance in both prokaryotic and human cells. The multidrug resistance phenotype is a cellular response to the presence of cytotoxic substances in the environment. The basic mechanism of multidrug resistance is overexpression of the membrane proteins involved in the extrusion of toxic substances outside the cell. The resistance mechanism based on the efflux of inhibitors as a result of the overproduction of transport proteins was also observed in some plant and animal pathogens and human tumour cells. The phenomenon of multidrug resistance associated with an excessive and long-term use of antifungals, in particular of azole derivatives, was also confirmed in the yeast Candida glabrata which is becoming a growing concern for health care professionals. Reduced susceptibility to azole derivatives in particular, a high potential for adapting to stressors, and multiple mechanisms of resistance to structurally and functionally unrelated antifungal drugs make the species C. glabrata a potential threat to hospital patients.

Candida Parapsilosis and Candida Guillermondii: Emerging Pathogens in Nail Candidiasis

PubMed Central

Fich, Felix; Abarzúa-Araya, Alvaro; Pérez, Mario; Nauhm, Yalile; León, Eugenia

2014-01-01

Background: Onychomycosis of the fingernails and toenails is generally caused by dermatophytes and yeasts. Toenail mycoses involve mainly dermatophytes but when Candida is also involved, the strain most commonly isolated worldwide is C. albicans. Aims: To determine Candida strains prevailing in onychomycosis. Materials and Methods: A retrospective, observational and descriptive study of fungal cultures retrieved from the registry of the microbiology laboratory of the Pontificia Universidad Católica was performed. Specimens obtained from patients attending the healthcare network between December 2007 and December 2010 was analyzed. Statistical Analysis: A descriptive statistical analysis was performed. Results: Candida was retrieved from 467 of 8443 specimens (52% fingernails and 48% toenails). Cultures were negative in 5320 specimens (63.6%). Among Candida-positive cultures, parapsilosis was the most commonly isolated strain with 202 cases (43.3%). While isolates of Candida guillermondii were 113 (24.2%), those of Candida albicans were 110 (23.6%), those of spp. were 20 (4.3%) and there were 22 cases of other isolates (4.71%). Among the 467 patients with positive cultures for Candida, 136 (29,1%) were men and 331 (70,9%) were women. All patients were older than 18 years old. Clinical files were available for only 169 of the 467 patients with positive cultures for Candida. For those, age, gender, underlying illnesses and use of immunossupresive agents during the trial was reviewed. Conclusions: The present study shows that both C. parapsilosis as well as C. guillermondii appear as emerging pathogens that would be in fact taking the place of C. albicans as the most commonly isolated pathogen in patients with Candida onychomycosis. The relative percentage of C parapsilosis increases every year. Identification of Candida strains as etiological agents of nail candidiasis becomes relevant to the management both nail as well as systemic candidiasis, in view of the resistance to conventional treatments readily reported in the literature. PMID:24470656

Comparative Phenotypic Analysis of the Major Fungal Pathogens Candida parapsilosis and Candida albicans

PubMed Central

Holland, Linda M.; Schröder, Markus S.; Turner, Siobhán A.; Taff, Heather; Andes, David; Grózer, Zsuzsanna; Gácser, Attila; Ames, Lauren; Haynes, Ken; Higgins, Desmond G.; Butler, Geraldine

2014-01-01

Candida parapsilosis and Candida albicans are human fungal pathogens that belong to the CTG clade in the Saccharomycotina. In contrast to C. albicans, relatively little is known about the virulence properties of C. parapsilosis, a pathogen particularly associated with infections of premature neonates. We describe here the construction of C. parapsilosis strains carrying double allele deletions of 100 transcription factors, protein kinases and species-specific genes. Two independent deletions were constructed for each target gene. Growth in >40 conditions was tested, including carbon source, temperature, and the presence of antifungal drugs. The phenotypes were compared to C. albicans strains with deletions of orthologous transcription factors. We found that many phenotypes are shared between the two species, such as the role of Upc2 as a regulator of azole resistance, and of CAP1 in the oxidative stress response. Others are unique to one species. For example, Cph2 plays a role in the hypoxic response in C. parapsilosis but not in C. albicans. We found extensive divergence between the biofilm regulators of the two species. We identified seven transcription factors and one protein kinase that are required for biofilm development in C. parapsilosis. Only three (Efg1, Bcr1 and Ace2) have similar effects on C. albicans biofilms, whereas Cph2, Czf1, Gzf3 and Ume6 have major roles in C. parapsilosis only. Two transcription factors (Brg1 and Tec1) with well-characterized roles in biofilm formation in C. albicans do not have the same function in C. parapsilosis. We also compared the transcription profile of C. parapsilosis and C. albicans biofilms. Our analysis suggests the processes shared between the two species are predominantly metabolic, and that Cph2 and Bcr1 are major biofilm regulators in C. parapsilosis. PMID:25233198

Understanding the Antifungal Mechanism of Ag@ZnO Core-shell Nanocomposites against Candida krusei.

PubMed

Das, Bhaskar; Khan, Md Imran; Jayabalan, R; Behera, Susanta K; Yun, Soon-Il; Tripathy, Suraj K; Mishra, Amrita

2016-11-04

In the present paper, facile synthesis of Ag@ZnO core-shell nanocomposites is reported where zinc oxide is coated on biogenic silver nanoparticles synthesized using Andrographis paniculata and Aloe vera leaf extract. Structural features of as synthesized nanocomposites are characterized by UV-visible spectroscopy, XRD, and FTIR. Morphology of the above core-shell nanocomposites is investigated by electron microscopy. As synthesized nanocomposite material has shown antimicrobial activity against Candida krusei, which is an opportunistic pathogen known to cause candidemia. The possible mode of activity of the above material has been studied by in-vitro molecular techniques. Our investigations have shown that surface coating of biogenic silver nanoparticles by zinc oxide has increased its antimicrobial efficiency against Candida krusei, while decreasing its toxicity towards A431 human epidermoid carcinoma cell lines.

Chlorine-rich plasma polymer coating for the prevention of attachment of pathogenic fungal cells onto materials surfaces

NASA Astrophysics Data System (ADS)

Lamont-Friedrich, Stephanie J.; Michl, Thomas D.; Giles, Carla; Griesser, Hans J.; Coad, Bryan R.

2016-07-01

The attachment of pathogenic fungal cells onto materials surfaces, which is often followed by biofilm formation, causes adverse consequences in a wide range of areas. Here we have investigated the ability of thin film coatings from chlorinated molecules to deter fungal colonization of solid materials by contact killing of fungal cells reaching the surface of the coating. Coatings were deposited onto various substrate materials via plasma polymerization, which is a substrate-independent process widely used for industrial coating applications, using 1,1,2-trichloroethane as the process vapour. XPS surface analysis showed that the coatings were characterized by a highly chlorinated hydrocarbon polymer nature, with only a very small amount of oxygen incorporated. The activity of these coatings against human fungal pathogens was quantified using a recently developed, modified yeast assay and excellent antifungal activity was observed against Candida albicans and Candida glabrata. Plasma polymer surface coatings derived from chlorinated hydrocarbon molecules may therefore offer a promising solution to preventing yeast and mould biofilm formation on materials surfaces, for applications such as air conditioners, biomedical devices, food processing equipment, and others.

Combinatorial drug approaches to tackle Candida albicans biofilms.

PubMed

De Cremer, Kaat; Staes, Ines; Delattin, Nicolas; Cammue, Bruno P A; Thevissen, Karin; De Brucker, Katrijn

2015-08-01

The human fungal opportunistic pathogen Candida albicans resides in the human gut, genitourinary tract and on the skin. The majority of infections caused by C. albicans are biofilm-related. In the first part of this review, we discuss new insights into C. albicans biofilm characteristics, concentrating on the extracellular matrix, phenotypic switching, efflux pumps and persister cells. It is widely accepted that this multicellular lifestyle is more resistant to traditional antifungal treatment compared to free-living cells. Therefore, much effort is put in the search for combinations of drugs leading to synergistic interactions against microbial biofilms to achieve lower effective doses of the drugs. In the second part of this manuscript, we review all recently identified compounds that act synergistically with azoles, echinocandins and/or polyenes against C. albicans biofilms.

Innocent until proven guilty: mechanisms and roles of Streptococcus–Candida interactions in oral health and disease

PubMed Central

Xu, H; Jenkinson, HF; Dongari-Bagtzoglou, A

2014-01-01

Summary Candida albicans and streptococci of the mitis group colonize the oral cavities of the majority of healthy humans. While C. albicans is considered an opportunistic pathogen, streptococci of this group are broadly considered avirulent or even beneficial organisms. However, recent evidence suggests that multi-species biofilms with these organisms may play detrimental roles in host homeostasis and may promote infection. In this review we summarize the literature on molecular interactions between members of this streptococcal group and C. albicans, with emphasis on their potential role in the pathogenesis of opportunistic oral mucosal infections. PMID:24877244

Clinical Appearance of Oral Candida Infection and Therapeutic Strategies

PubMed Central

Patil, Shankargouda; Rao, Roopa S.; Majumdar, Barnali; Anil, Sukumaran

2015-01-01

Candida species present both as commensals and opportunistic pathogens of the oral cavity. For decades, it has enthralled the clinicians to investigate its pathogenicity and to improvise newer therapeutic regimens based on the updated molecular research. Candida is readily isolated from the oral cavity, but simple carriage does not predictably result in development of an infection. Whether it remains as a commensal, or transmutes into a pathogen, is usually determined by pre-existing or associated variations in the host immune system. The candida infections may range from non-life threatening superficial mucocutaneous disorders to invasive disseminated disease involving multiple organs. In fact, with the increase in number of AIDS cases, there is a resurgence of less common forms of oral candida infections. The treatment after confirmation of the diagnosis should include recognizing and eliminating the underlying causes such as ill-fitting oral appliances, history of medications (antibiotics, corticosteroids, etc.), immunological and endocrine disorders, nutritional deficiency states and prolonged hospitalization. Treatment with appropriate topical antifungal agents such as amphotericin, nystatin, or miconazole usually resolves the symptoms of superficial infection. Occasionally, administration of systemic antifungal agents may be necessary in immunocompromised patients, the selection of which should be based upon history of recent azole exposure, a history of intolerance to an antifungal agent, the dominant Candida species and current susceptibility data. PMID:26733948

Saccharomyces cerevisiae show low levels of traversal across human endothelial barrier in vitro.

PubMed

Pérez-Torrado, Roberto; Querol, Amparo

2017-01-01

Background :   Saccharomyces cerevisiae is generally considered safe, and is involved in the production of many types of foods and dietary supplements. However, some isolates, which are genetically related to strains used in brewing and baking, have shown virulent traits, being able to produce infections in humans, mainly in immunodeficient patients. This can lead to systemic infections in humans. Methods : In this work, we studied S. cerevisiae isolates in an in vitro human endothelial barrier model, comparing their behaviour with that of several strains of the related pathogens Candida glabrata and Candida albicans . Results : The results showed that this food related yeast is able to cross the endothelial barrier in vitro . However, in contrast to C. glabrata and C. albicans , S. cerevisiae showed very low levels of traversal. Conclusions : We conclude that using an in vitro human endothelial barrier model with S. cerevisiae can be useful to evaluate the safety of S. cerevisiae strains isolated from foods.

A diterpenoid taxodone from Metasequoia glyptostroboides with antimycotic potential against clinical isolates of Candida species.

PubMed

Bajpai, V K; Park, Y-H; Kang, S C

2015-03-01

The increasing importance of clinical isolates of Candida species and emerging resistance of Candida species to current synthetic antifungal agents have stimulated the search for safer and more effective alternative drugs from natural sources. This study was directed towards exploring the antimycotic potential of a diterpenoid compound taxodone isolated from Metasequoia glyptostroboides against pathogenic isolates of Candida species. Antimycotic efficacy of taxodone was evaluated by disc diffusion assay, determination of minimum inhibitory (MIC) and minimum fungicidal (MFC) concentrations, and cell viability assay. To confirm a partial antimycotic mode of action of taxodone, the efficacy of taxodone was determined by measuring the release of 260 nm absorbing materials from the selected Candida species as compared to control. The taxodone at the concentration of 400 μg/disc displayed potential antimycotic effect against the tested clinical and pathogenic isolates of Candida species as diameters of zones of inhibitions, which were found in the range of 11 ± 0.0 to 12.6 ± 0.5mm. The MIC and MFC values of taxodone against the tested clinical isolates were found in the range of 250 to 1000 and 500 to 2000μ g/mL, respectively. On the other hand, the MIC and MFC values of positive control (amphotericin B) against the tested Candida isolates were found in the range of 62.5 to 250 and 500 to 2000 μg/mL. On the viable counts of the tested fungal isolates, the taxodone exerted significant antimycotic effect. Elaborative study of partial mode of action conducted onto the release of 260nm materials (DNA and RNA) revealed potential detrimental effect of taxodone on the membrane integrity of the tested pathogens at MIC concentration. With respect to the antimycotic effect of taxodone against pathogenic and clinical isolates of Candida species, it might be confirmed that bioactive compound taxodone present in M. glyptostroboides holds therapeutic value of medicinal significance. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Genome Sequence of the Yeast Clavispora lusitaniae Type Strain CBS 6936.

PubMed

Durrens, Pascal; Klopp, Christophe; Biteau, Nicolas; Fitton-Ouhabi, Valérie; Dementhon, Karine; Accoceberry, Isabelle; Sherman, David J; Noël, Thierry

2017-08-03

Clavispora lusitaniae , an environmental saprophytic yeast belonging to the CTG clade of Candida , can behave occasionally as an opportunistic pathogen in humans. We report here the genome sequence of the type strain CBS 6936. Comparison with sequences of strain ATCC 42720 indicates conservation of chromosomal structure but significant nucleotide divergence. Copyright © 2017 Durrens et al.

Genome Sequence of the Yeast Clavispora lusitaniae Type Strain CBS 6936

PubMed Central

Klopp, Christophe; Biteau, Nicolas; Fitton-Ouhabi, Valérie; Dementhon, Karine; Accoceberry, Isabelle; Sherman, David J.; Noël, Thierry

2017-01-01

ABSTRACT Clavispora lusitaniae, an environmental saprophytic yeast belonging to the CTG clade of Candida, can behave occasionally as an opportunistic pathogen in humans. We report here the genome sequence of the type strain CBS 6936. Comparison with sequences of strain ATCC 42720 indicates conservation of chromosomal structure but significant nucleotide divergence. PMID:28774979

Antimicrobial potential of 27 plants consumed by chimpanzees (Pan troglodytes verus Blumenbach) in Ivory Coast.

PubMed

Ahoua, Angora Rémi Constant; Konan, Amoin Georgette; Bonfoh, Bassirou; Koné, Mamidou Witabouna

2015-10-23

Due to their genetic proximity, chimpanzees share with human several diseases including bacterial, fungal and viral infections, such as candidiasis, acquired immune deficiency syndrome (AIDS), Ebola virus disease. However, in its natural environment, chimpanzees are tolerant to several pathogens including simian immunodeficiency virus (SIV), virus related to human immunodeficiency virus (HIV) that contribute to the emergence of opportunistic diseases such as microbial infections. Twenty seven species of plants consumed by chimpanzees were evaluated for their antimicrobial potential against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans, Candida tropicalis and Candida glabrata using the agar diffusion technique and micro-dilution in 96-well plates. In total 132 extracts (33 dichloromethane, 33 methanol, 33 ethyl acetate and 33 aqueous) were tested. The results showed that 24 extracts (18 %) showed activity against bacteria and 6 extracts (5 %) were active against yeasts. The minimal inhibitory concentrations (MICs) values of active extracts ranged between 23 and 750 μg/ml for bacteria and between 188 and 1500 μg/ml for yeasts. Tristemma coronatum was the most promising on the studied microorganisms followed by Beilschmiedia mannii. The extracts of the two plants indicated by chimpanzees have potential for antimicrobial use in human.

The effect of ultraviolet radiation on the pathogenesis of Candida albicans in mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denkins, Y.M.

1991-01-01

This dissertation addresses questions concerning the effects of UV radiation on the pathogenesis of opportunistic fungal pathogens such as Candida albicans. UV radiation decreased the survival of Candida-infected mice; however, no correlation was found between suppression of the delayed type hypersensitivity (DTH) response and the course of lethal infection. This suggested that DTH was not protective against lethal disease with this organism. UV radiation also changed the persistence of the organism in the internal organs. UV-irradiated, infected animals had increased numbers of Candida in their kidneys compared to non-irradiated mice. Sensitization prior to UV irradiation aided clearance of the organismmore » from the kidneys of UV-irradiated mice. These data show that UV radiation suppresses cell-mediated immunity to Candida albicans in mice and increases mortality of Candida-infected mice. Moreover, the data suggest that an increase in environmental UV radiation could increase the severity of pathogenic infections.« less

Tramadol, an Opioid Receptor Agonist: An Inhibitor of Growth, Morphogenesis, and Biofilm Formation in the Human Pathogen, Candida albicans.

PubMed

Kathwate, Gunderao Hanumantrao; Karuppayil, S Mohan

2016-12-01

Tramadol is a synthetic, centrally acting low-affinity agonist of μ-opioid receptors in humans. It is used as an analgesic and is shown to have local anesthetic action. In this study, we have tried to explore its anti-Candida potential. Minimum inhibitory concentration (MIC50) and minimum fungicidal concentration (MFC) values were established. MIC50 ranged from 2 to 4 mg/mL, whereas MFC was recorded at 8 mg/mL. Also, the effect of tramadol on germ tube formation, adhesion, and biofilms in Candida albicans was studied. Tramadol impaired in vitro growth of C. albicans. A time-dependent killing assay showed that it kills C. albicans within 24 h of exposure. Tramadol has strong activity against Candida virulence factors such as yeast-to-hyphal form switching and adhesion. C. albicans biofilms, which are notoriously resistant to many antifungals, were sensitive to tramadol. At 8 mg/mL of tramadol, 82% of early stage biofilms and 52.88% of matured biofilms were inhibited. Although our results show that the antifungal effect of tramadol requires concentrations that can be achieved only locally, they may provide potential candidates for development of novel antifungal drugs.

Molecular characterization of Candida isolates from intensive care unit patients, Krakow, Poland.

PubMed

Małek, Marianna; Paluchowska, Paulina; Bogusz, Bożena; Budak, Alicja

Over the last decades, Candida species have emerged as important pathogens in immunocompromised patients. Nosocomial infections are mainly of endogenous origin. Nevertheless, some cases of exogenous candidiasis have also been reported. The aim of this study was to evaluate the genetic relatedness between Candida albicans, Candida glabrata, Candida tropicalis, Candida krusei and Candida kefyr isolates recovered from intensive care unit (ICU) patients. A total of 132 Candida clinical isolates (62 C. albicans, 40 C. glabrata, 13 C. tropicalis, 11 C. krusei, 6 C. kefyr), obtained from specimens of endotracheal aspirate, urine and blood taken from patients of a tertiary hospital in Poland, were included in the study. Species identification was performed by PCR method and genetic relatedness was assessed by randomly amplified polymorphic DNA assay (RAPD) with five primers. The RAPD analysis revealed high genetic diversity among the studied Candida isolates, indicating that most of the strains were from endogenous sources. Only two clonal strains of C. glabrata isolated from different patients were observed, suggesting a possible cross-transmission of these pathogens. Our study confirmed the high discriminatory power of the RAPD assay. This genotyping method can be applied to local epidemiological studies of Candida species. Copyright © 2016 Asociación Española de Micología. Publicado por Elsevier España, S.L.U. All rights reserved.

Antifungal agents commonly used in the superficial and mucosal candidiasis treatment: mode of action and resistance development

PubMed Central

Bondaryk, Małgorzata; Kurzątkowski, Wiesław

2013-01-01

Recent progress in medical sciences and therapy resulted in an increased number of immunocompromised individuals. Candida albicans is the leading opportunistic fungal pathogen causing infections in humans, ranging from superficial mucosal lesions to disseminated or bloodstream candidiasis. Superficial candidiasis not always presents a risk to the life of the infected host, however it significantly lowers the quality of life. Superficial Candida infections are difficult to treat and their frequency of occurrence is currently rising. To implement successful treatment doctors should be up to date with better understanding of C. albicans resistance mechanisms. Despite high frequency of Candida infections there is a limited number of antimycotics available for therapy. This review focuses on current understanding of the mode of action and resistance mechanisms to conventional and emerging antifungal agents for treatment of superficial and mucosal candidiasis. PMID:24353489

Antifungal activity of different neem leaf extracts and the nimonol against some important human pathogens

PubMed Central

Mahmoud, D.A.; Hassanein, N.M.; Youssef, K.A.; Abou Zeid, M.A.

2011-01-01

This study was conducted to evaluate the effect of aqueous, ethanolic and ethyl acetate extracts from neem leaves on growth of some human pathogens (Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Aspergillus terreus, Candida albicans and Microsporum gypseum) in vitro. Different concentrations (5, 10, 15 and 20%) prepared from these extracts inhibited the growth of the test pathogens and the effect gradually increased with concentration. The 20% ethyl acetate extract gave the strongest inhibition compared with the activity obtained by the same concentration of the other extracts. High Performance Liquid Chromatography (HPLC) analysis of ethyl acetate extract showed the presence of a main component (nimonol) which was purified and chemically confirmed by Nuclear Magnetic Resonance (NMR) spectroscopic analysis. The 20% ethyl acetate extract lost a part of its antifungal effect after pooling out the nimonol and this loss in activity was variable on test pathogens. The purified nimonol as a separate compound did not show any antifungal activity when assayed against all the six fungal pathogens. PMID:24031718

CARD9-Dependent Neutrophil Recruitment Protects against Fungal Invasion of the Central Nervous System

PubMed Central

Swamydas, Muthulekha; Rodriguez, Carlos A.; Lim, Jean K.; Mendez, Laura M.; Fink, Danielle L.; Hsu, Amy P.; Zhai, Bing; Karauzum, Hatice; Mikelis, Constantinos M.; Rose, Stacey R.; Ferre, Elise M. N.; Yockey, Lynne; Lemberg, Kimberly; Kuehn, Hye Sun; Rosenzweig, Sergio D.; Lin, Xin; Chittiboina, Prashant; Datta, Sandip K.; Belhorn, Thomas H.; Weimer, Eric T.; Hernandez, Michelle L.; Hohl, Tobias M.; Kuhns, Douglas B.; Lionakis, Michail S.

2015-01-01

Candida is the most common human fungal pathogen and causes systemic infections that require neutrophils for effective host defense. Humans deficient in the C-type lectin pathway adaptor protein CARD9 develop spontaneous fungal disease that targets the central nervous system (CNS). However, how CARD9 promotes protective antifungal immunity in the CNS remains unclear. Here, we show that a patient with CARD9 deficiency had impaired neutrophil accumulation and induction of neutrophil-recruiting CXC chemokines in the cerebrospinal fluid despite uncontrolled CNS Candida infection. We phenocopied the human susceptibility in Card9 -/- mice, which develop uncontrolled brain candidiasis with diminished neutrophil accumulation. The induction of neutrophil-recruiting CXC chemokines is significantly impaired in infected Card9 -/- brains, from both myeloid and resident glial cellular sources, whereas cell-intrinsic neutrophil chemotaxis is Card9-independent. Taken together, our data highlight the critical role of CARD9-dependent neutrophil trafficking into the CNS and provide novel insight into the CNS fungal susceptibility of CARD9-deficient humans. PMID:26679537

Expressed Sequence Tag Analysis of the Human Pathogen Paracoccidioides brasiliensis Yeast Phase: Identification of Putative Homologues of Candida albicans Virulence and Pathogenicity Genes

PubMed Central

Goldman, Gustavo H.; dos Reis Marques, Everaldo; Custódio Duarte Ribeiro, Diógenes; Ângelo de Souza Bernardes, Luciano; Quiapin, Andréa Carla; Vitorelli, Patrícia Marostica; Savoldi, Marcela; Semighini, Camile P.; de Oliveira, Regina C.; Nunes, Luiz R.; Travassos, Luiz R.; Puccia, Rosana; Batista, Wagner L.; Ferreira, Leslie Ecker; Moreira, Júlio C.; Bogossian, Ana Paula; Tekaia, Fredj; Nobrega, Marina Pasetto; Nobrega, Francisco G.; Goldman, Maria Helena S.

2003-01-01

Paracoccidioides brasiliensis, a thermodimorphic fungus, is the causative agent of the prevalent systemic mycosis in Latin America, paracoccidioidomycosis. We present here a survey of expressed genes in the yeast pathogenic phase of P. brasiliensis. We obtained 13,490 expressed sequence tags from both 5′ and 3′ ends. Clustering analysis yielded the partial sequences of 4,692 expressed genes that were functionally classified by similarity to known genes. We have identified several Candida albicans virulence and pathogenicity homologues in P. brasiliensis. Furthermore, we have analyzed the expression of some of these genes during the dimorphic yeast-mycelium-yeast transition by real-time quantitative reverse transcription-PCR. Clustering analysis of the mycelium-yeast transition revealed three groups: (i) RBT, hydrophobin, and isocitrate lyase; (ii) malate dehydrogenase, contigs Pb1067 and Pb1145, GPI, and alternative oxidase; and (iii) ubiquitin, delta-9-desaturase, HSP70, HSP82, and HSP104. The first two groups displayed high mRNA expression in the mycelial phase, whereas the third group showed higher mRNA expression in the yeast phase. Our results suggest the possible conservation of pathogenicity and virulence mechanisms among fungi, expand considerably gene identification in P. brasiliensis, and provide a broader basis for further progress in understanding its biological peculiarities. PMID:12582121

IL-17-mediated immunity to the opportunistic fungal pathogen Candida albicans

PubMed Central

Conti, Heather R.; Gaffen, Sarah L.

2015-01-01

IL-17 (IL-17A) has emerged as a key mediator of protection against extracellular microbes, but this cytokine also drives pathology in various autoimmune diseases. Overwhelming data in both humans and mice reveal a clear and surprisingly specific role for IL-17 in protection against the fungus Candida albicans, a commensal of the human oral cavity, gastrointestinal tract and reproductive mucosa. The IL-17 pathway regulates antifungal immunity through upregulation of pro-inflammatory cytokines including IL-6, neutrophil-recruiting chemokines such as CXCL1 and CXCL5 and antimicrobial peptides such as the defensins, which act in concert to limit fungal overgrowth. This review will focus on diseases caused by C. albicans, the role of IL-17-mediated immunity in candidiasis, and the implications for clinical therapies for both autoimmune conditions and fungal infections. PMID:26188072

Molecular epidemiology, phylogeny and evolution of Candida albicans.

PubMed

McManus, Brenda A; Coleman, David C

2014-01-01

A small number of Candida species form part of the normal microbial flora of mucosal surfaces in humans and may give rise to opportunistic infections when host defences are impaired. Candida albicans is by far the most prevalent commensal and pathogenic Candida species. Several different molecular typing approaches including multilocus sequence typing, multilocus microsatellite typing and DNA fingerprinting using C. albicans-specific repetitive sequence-containing DNA probes have yielded a wealth of information regarding the epidemiology and population structure of this species. Such studies revealed that the C. albicans population structure consists of multiple major and minor clades, some of which exhibit geographical or phenotypic enrichment and that C. albicans reproduction is predominantly clonal. Despite this, losses of heterozygosity by recombination, the existence of a parasexual cycle, toleration of a wide range of aneuploidies and the recent description of viable haploid strains have all demonstrated the extensive plasticity of the C. albicans genome. Recombination and gross chromosomal rearrangements are more common under stressful environmental conditions, and have played a significant role in the evolution of this opportunistic pathogen. Surprisingly, Candida dubliniensis, the closest relative of C. albicans exhibits more karyotype variability than C. albicans, but is significantly less adaptable to unfavourable environments. This disparity most likely reflects the evolutionary processes that occurred during or soon after the divergence of both species from their common ancestor. Whilst C. dubliniensis underwent significant gene loss and pseudogenisation, C. albicans expanded gene families considered to be important in virulence. It is likely that technological developments in whole genome sequencing and data analysis in coming years will facilitate its routine use for population structure, epidemiological investigations, and phylogenetic analyses of Candida species. These are likely to reveal more minor C. albicans clades and to enhance our understanding of the population biology of this versatile organism. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

Quantification of oral palatine Langerhans cells in HIV/AIDS associated oral Kaposi sarcoma with and without oral candidiasis.

PubMed

Jivan, Vibha; Meer, Shabnum

2016-01-01

Langerhans cells (LCs) are effective antigen-presenting cells that function as "custodians" of mucosa, modifying the immune system to pathogen entry, and tolerance to self-antigen and commensal microbes. A reduction in number of LCs in human immunodeficiency virus (HIV)-positive individuals may predispose to local mucosal infections. To quantitatively determine the number of oral mucosal LCs in HIV/acquired immunodeficiency syndrome HIV/acquired immunodeficiency syndrome (AIDS) associated oral Kaposi sarcoma (KS) with/without oral candidiasis (OC) and to define in situ interrelationships between the cells, OC, and HIV infection. Thirty-two periodic acid-Schiff. (PAS) stained histologic sections of palatal HIV/AIDS associated KS with intact oral epithelium were examined for Candida and divided into two groups: . (1) KS coinfected with Candida and. (2) KS noninfected with Candida. Sections were immunohistochemically stained with CD1a. The standard length of surface epithelium was measured and number of positively stained LCs counted per unit length. Control cases included non-Candida infected palatal mucosa overlying pleomorphic adenoma. (PA) and oral mucosa infected with Candida in otherwise healthy individuals. LC number per unit length of surface epithelium was statistically significantly greatest in uninfected PA mucosa and lowest in KS coinfected with Candida (P = 0.0001). A statistically significant difference was also noted between uninfected PA mucosa and non-Candida infected KS (P = 0.0014), in KS coinfected with Candida and non-infected KS (P = 0.0035), between OC and PA (P = 0.0001), and OC and KS coinfected with Candida (P = 0.0247). LC numbers are significantly reduced in oral tissues of HIV/AIDS infected patients by Candida infection when compared to oral tissues without.

High frame-rate resolution of cell division during Candida albicans filamentation

PubMed Central

Thomson, Darren D.; Berman, Judith; Brand, Alexandra C.

2016-01-01

The commensal yeast, Candida albicans, is an opportunistic pathogen in humans and forms filaments called hyphae and pseudohyphae, in which cell division requires precise temporal and spatial control to produce mononuclear cell compartments. High-frame-rate live-cell imaging (1 frame/min) revealed that nuclear division did not occur across the septal plane. We detected the presence of nucleolar fragments that may be extrachromosomal molecules carrying the ribosomal RNA genes. Cells occasionally maintained multiple nucleoli, suggesting either polyploidy, multiple nuclei and/or aneuploidy of ChrR., while the migration pattern of sister nuclei differed between unbranched and branched hyphae. The presented movie challenges and extends previous concepts of C. albicans cell division. PMID:26854071

Diorcinol D Exerts Fungicidal Action against Candida albicans through Cytoplasm Membrane Destruction and ROS Accumulation

PubMed Central

Li, Ying; Chang, Wenqiang; Zhang, Ming; Li, Xiaobin; Jiao, Yang; Lou, Hongxiang

2015-01-01

Candida albicans, which is the most common human fungal pathogen, causes high mortality among immunocompromised patients. Antifungal drug resistance becomes a major challenge for the management of Candida infection. Diorcinol D (DD), a diphenyl ether derivative isolated from an endolichenic fungus, exerted fungicidal action against Candida species. In this study, we investigated the possible mechanism of its antifungal activity. The change of membrane dynamics and permeability suggested that the cell membrane was disrupted by the treatment of DD. This was further supported by the evidences of intracellular glycerol accumulation, alteration of cell ultrastructure, and down-regulation of genes involved in cell membrane synthesis. In addition, the treatment of C. albicans with DD resulted in the elevation of reactive oxygen species (ROS), which caused the dysfunction of mitochondria. These altogether suggested that DD exerted its antifungal activity through cytoplasmic membrane destruction and ROS accumulation. This finding is helpful to uncover the underlying mechanisms for the diphenyl ether derivatives and provides a potential application in fighting clinical fungal infections. PMID:26047493

Evolution and Application of Inteins in Candida species: A Review

PubMed Central

Fernandes, José A. L.; Prandini, Tâmara H. R.; Castro, Maria da Conceiçao A.; Arantes, Thales D.; Giacobino, Juliana; Bagagli, Eduardo; Theodoro, Raquel C.

2016-01-01

Inteins are invasive intervening sequences that perform an autocatalytic splicing from their host proteins. Among eukaryotes, these elements are present in many fungal species, including those considered opportunistic or primary pathogens, such as Candida spp. Here we reviewed and updated the list of Candida species containing inteins in the genes VMA, THRRS and GLT1 and pointed out the importance of these elements as molecular markers for molecular epidemiological researches and species-specific diagnosis, since the presence, as well as the size of these inteins, is polymorphic among the different species. Although absent in Candida albicans, these elements are present in different sizes, in some environmental Candida spp. and also in most of the non-albicans Candida spp. considered emergent opportunistic pathogens. Besides, the possible role of these inteins in yeast physiology was also discussed in the light of the recent findings on the importance of these elements as post-translational modulators of gene expression, reinforcing their relevance as alternative therapeutic targets for the treatment of non-albicans Candida infections, because, once the splicing of an intein is inhibited, its host protein, which is usually a housekeeping protein, becomes non-functional. PMID:27777569

In Vitro Activities of Terbinafine against Cutaneous Isolates of Candida albicans and Other Pathogenic Yeasts

PubMed Central

Ryder, Neil S.; Wagner, Sonja; Leitner, Ingrid

1998-01-01

Terbinafine is active in vitro against a wide range of pathogenic fungi, including dermatophytes, molds, dimorphic fungi, and some yeasts, but earlier studies indicated that the drug had little activity against Candida albicans. In contrast, clinical studies have shown topical and oral terbinafine to be active in cutaneous candidiasis and Candida nail infections. In order to define the anti-Candida activity of terbinafine, we tested the drug against 350 fresh clinical isolates and additional strains by using a broth dilution assay standardized according to the guidelines of the National Committee for Clinical Laboratory Standards (NCCLS) M27-A assay. Terbinafine was found to have an MIC of 1 μg/ml for reference C. albicans strains. For 259 clinical isolates, the MIC at which 50% of the isolates are inhibited (MIC50) of terbinafine was 1 μg/ml (fluconazole, 0.5 μg/ml), and the MIC90 was 4 μg/ml (fluconazole, 1 μg/ml). Terbinafine was highly active against Candida parapsilosis (MIC90, 0.125 μg/ml) and showed potentially interesting activity against isolates of Candida dubliniensis, Candida guilliermondii, Candida humicola, and Candida lusitaniae. It was not active against the Candida glabrata, Candida krusei, and Candida tropicalis isolates in this assay. Cryptococcus laurentii and Cryptococcus neoformans were highly susceptible to terbinafine, with MICs of 0.06 to 0.25 μg/ml. The NCCLS macrodilution assay provides reproducible in vitro data for terbinafine against Candida and other yeasts. The MICs for C. albicans and C. parapsilosis are compatible with the known clinical efficacy of terbinafine in cutaneous infections, while the clinical relevance of its activities against the other species has yet to be determined. PMID:9593126

Systemic and mucosal immunization with Candida albicans hsp90 elicits hsp90-specific humoral response in vaginal mucosa which is further enhanced during experimental vaginal candidiasis.

PubMed

Raska, Milan; Belakova, Jana; Horynova, Milada; Krupka, Michal; Novotny, Jiri; Sebestova, Martina; Weigl, Evzen

2008-08-01

The Candida albicans heat shock protein 90 kDa (hsp90-CA) is an important target for protective antibodies in disseminated candidiasis of experimental mice and humans. Hsp90-CA is present in the cell wall of Candida pseudohyphae or hyphae--typical pathogenic morphotypes in both mucosal and systemic Candida infections. However, the potential protective effects of hsp90-CA-specific antibodies in vaginal candidiasis has not yet been reported. In the present study we used various vaccine formulations (recombinant hsp90-CA protein and hsp90-CA-encoding DNA vaccine) and routes of administration (intradermal, intranasal, and intravenous) to induce both hsp90-CA-specific systemic and vaginal mucosa immune responses in experimental BALB/c mice. The results showed that intradermal recombinant hsp90-CA protein priming, followed by intranasal or intradermal recombinant hsp90-CA protein boosting induced significant increases in both serum and vaginal hsp90-CA-specific IgG and IgA antibodies compared to the control group, as well as enhanced hsp90-CA-specific splenocyte responses in vitro. In the intradermally boosted group, subsequent experimental vaginal Candida infection induced additional increases in the hsp90-CA specific IgG isotype, suggesting that Candida has the ability to induce a local hsp90-specific antibody (IgG) response during vulvovaginal candidiasis. Further work is required to elucidate the importance of immunity to highly conserved antigens during infection of the human female reproductive tract where a balance between immunity to and tolerance for commonly antigens such as hsp90 is necessary for the maintenance of fertility.

Systematic Phenotyping of a Large-Scale Candida glabrata Deletion Collection Reveals Novel Antifungal Tolerance Genes

PubMed Central

Hiller, Ekkehard; Istel, Fabian; Tscherner, Michael; Brunke, Sascha; Ames, Lauren; Firon, Arnaud; Green, Brian; Cabral, Vitor; Marcet-Houben, Marina; Jacobsen, Ilse D.; Quintin, Jessica; Seider, Katja; Frohner, Ingrid; Glaser, Walter; Jungwirth, Helmut; Bachellier-Bassi, Sophie; Chauvel, Murielle; Zeidler, Ute; Ferrandon, Dominique; Gabaldón, Toni; Hube, Bernhard; d'Enfert, Christophe; Rupp, Steffen; Cormack, Brendan; Haynes, Ken; Kuchler, Karl

2014-01-01

The opportunistic fungal pathogen Candida glabrata is a frequent cause of candidiasis, causing infections ranging from superficial to life-threatening disseminated disease. The inherent tolerance of C. glabrata to azole drugs makes this pathogen a serious clinical threat. To identify novel genes implicated in antifungal drug tolerance, we have constructed a large-scale C. glabrata deletion library consisting of 619 unique, individually bar-coded mutant strains, each lacking one specific gene, all together representing almost 12% of the genome. Functional analysis of this library in a series of phenotypic and fitness assays identified numerous genes required for growth of C. glabrata under normal or specific stress conditions, as well as a number of novel genes involved in tolerance to clinically important antifungal drugs such as azoles and echinocandins. We identified 38 deletion strains displaying strongly increased susceptibility to caspofungin, 28 of which encoding proteins that have not previously been linked to echinocandin tolerance. Our results demonstrate the potential of the C. glabrata mutant collection as a valuable resource in functional genomics studies of this important fungal pathogen of humans, and to facilitate the identification of putative novel antifungal drug target and virulence genes. PMID:24945925

Candida albicans and Pseudomonas aeruginosa Interaction, with Focus on the Role of Eicosanoids

PubMed Central

Fourie, Ruan; Ells, Ruan; Swart, Chantel W.; Sebolai, Olihile M.; Albertyn, Jacobus; Pohl, Carolina H.

2016-01-01

Candida albicans is commonly found in mixed infections with Pseudomonas aeruginosa, especially in the lungs of cystic fibrosis (CF) patients. Both of these opportunistic pathogens are able to form resistant biofilms and frequently infect immunocompromised individuals. The interaction between these two pathogens, which includes physical interaction as well as secreted factors, is mainly antagonistic. In addition, research suggests considerable interaction with their host, especially with immunomodulatory lipid mediators, termed eicosanoids. Candida albicans and Pseudomonas aeruginosa are both able to utilize arachidonic acid (AA), liberated from the host cells during infection, to form eicosanoids. The production of these eicosanoids, such as Prostaglandin E2, by the host and the pathogens may affect the dynamics of polymicrobial infection and the outcome of infections. It is of considerable importance to elucidate the role of host-produced, as well as pathogen-produced eicosanoids in polymicrobial infection. This review will focus on in vitro as well as in vivo interaction between C. albicans and P. aeruginosa, paying special attention to the role of eicosanoids in the cross-talk between host and the pathogens. PMID:26955357

Factors Supporting Cysteine Tolerance and Sulfite Production in Candida albicans

PubMed Central

Hennicke, Florian; Grumbt, Maria; Lermann, Ulrich; Ueberschaar, Nico; Palige, Katja; Böttcher, Bettina; Jacobsen, Ilse D.; Staib, Claudia; Morschhäuser, Joachim; Monod, Michel; Hube, Bernhard; Hertweck, Christian

2013-01-01

The amino acid cysteine has long been known to be toxic at elevated levels for bacteria, fungi, and humans. However, mechanisms of cysteine tolerance in microbes remain largely obscure. Here we show that the human pathogenic yeast Candida albicans excretes sulfite when confronted with increasing cysteine concentrations. Mutant construction and phenotypic analysis revealed that sulfite formation from cysteine in C. albicans relies on cysteine dioxygenase Cdg1, an enzyme with similar functions in humans. Environmental cysteine induced not only the expression of the CDG1 gene in C. albicans, but also the expression of SSU1, encoding a putative sulfite efflux pump. Accordingly, the deletion of SSU1 resulted in enhanced sensitivity of the fungal cells to both cysteine and sulfite. To study the regulation of sulfite/cysteine tolerance in more detail, we screened a C. albicans library of transcription factor mutants in the presence of sulfite. This approach and subsequent independent mutant analysis identified the zinc cluster transcription factor Zcf2 to govern sulfite/cysteine tolerance, as well as cysteine-inducible SSU1 and CDG1 gene expression. cdg1Δ and ssu1Δ mutants displayed reduced hypha formation in the presence of cysteine, indicating a possible role of the newly proposed mechanisms of cysteine tolerance and sulfite secretion in the pathogenicity of C. albicans. Moreover, cdg1Δ mutants induced delayed mortality in a mouse model of disseminated infection. Since sulfite is toxic and a potent reducing agent, its production by C. albicans suggests diverse roles during host adaptation and pathogenicity. PMID:23417561

First report of sporadic cases of Candida auris in Colombia.

PubMed

Parra-Giraldo, Claudia M; Valderrama, Sandra L; Cortes-Fraile, Gloria; Garzón, Javier R; Ariza, Beatriz E; Morio, Florent; Linares-Linares, Melva Y; Ceballos-Garzón, Andrés; de la Hoz, Alejandro; Hernandez, Catalina; Alvarez-Moreno, Carlos; Le Pape, Patrice

2018-04-01

Candida auris is a recently reported Candida species that is phenotypically similar to Candida haemulonii and related to hospital outbreaks. This organism can be misidentified as Candida haemulonii, Candida famata, Candida catenulata, or Rhodotorula glutinis by phenotypic approaches. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and DNA sequence analysis using internal transcribed spacer rDNA bar-coding provide an accurate identification. Three cases of C. auris infection in patients with risk factors for fungal infection (one admitted to the intensive care unit, one with lymphoma, and one with HIV; all three with previous antibiotic use) are reported; these infections were not epidemiologically related. Yeast isolates were recovered from blood, ocular secretion, and bronchoalveolar lavage and were misidentified as C. catenulata and Candida albicans by the phenotypic MicroScan method. The isolates were confirmed to be C. auris by means of MALDI-TOF MS and DNA sequence analysis. Antifungal susceptibility testing was performed on these C. auris isolates, which exhibited high minimum inhibitory concentrations to triazoles and amphotericin B. One patient survived and the other two died. Only one of these deaths was related to fungemia. C. auris is an emerging and opportunistic multidrug-resistant human pathogen. It is necessary to strengthen measures to achieve an accurate and quick identification and also to avoid its dissemination. This will require improvements in health and infection control measures, as well as the promotion of antifungal stewardship in healthcare facilities. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Use of phylogenetical analysis to predict susceptibility of pathogenic Candida spp. to antifungal drugs.

PubMed

Maheux, Andrée F; Sellam, Adnane; Piché, Yves; Boissinot, Maurice; Pelletier, René; Boudreau, Dominique K; Picard, François J; Trépanier, Hélène; Boily, Marie-Josée; Ouellette, Marc; Roy, Paul H; Bergeron, Michel G

2016-12-01

Successful treatment of a Candida infection relies on 1) an accurate identification of the pathogenic fungus and 2) on its susceptibility to antifungal drugs. In the present study we investigated the level of correlation between phylogenetical evolution and susceptibility of pathogenic Candida spp. to antifungal drugs. For this, we compared a phylogenetic tree, assembled with the concatenated sequences (2475-bp) of the ATP2, TEF1, and TUF1 genes from 20 representative Candida species, with published minimal inhibitory concentrations (MIC) of the four principal antifungal drug classes commonly used in the treatment of candidiasis: polyenes, triazoles, nucleoside analogues, and echinocandins. The phylogenetic tree revealed three distinct phylogenetic clusters among Candida species. Species within a given phylogenetic cluster have generally similar susceptibility profiles to antifungal drugs and species within Clusters II and III were less sensitive to antifungal drugs than Cluster I species. These results showed that phylogenetical relationship between clusters and susceptibility to several antifungal drugs could be used to guide therapy when only species identification is available prior to information pertaining to its resistance profile. An extended study comprising a large panel of clinical samples should be conducted to confirm the efficiency of this approach in the treatment of candidiasis. Copyright © 2016. Published by Elsevier B.V.

Rapid and Accurate Molecular Identification of the Emerging Multidrug-Resistant Pathogen Candida auris

PubMed Central

Zhao, Yanan; Lockhart, Shawn R.; Berrio, Indira

2017-01-01

ABSTRACT Candida auris is an emerging multidrug-resistant fungal pathogen causing nosocomial and invasive infections associated with high mortality. C. auris is commonly misidentified as several different yeast species by commercially available phenotypic identification platforms. Thus, there is an urgent need for a reliable diagnostic method. In this paper, we present fast, robust, easy-to-perform and interpret PCR and real-time PCR assays to identify C. auris and related species: Candida duobushaemulonii, Candida haemulonii, and Candida lusitaniae. Targeting rDNA region nucleotide sequences, primers specific for C. auris only or C. auris and related species were designed. A panel of 140 clinical fungal isolates was used in both PCR and real-time PCR assays followed by electrophoresis or melting temperature analysis, respectively. The identification results from the assays were 100% concordant with DNA sequencing results. These molecular assays overcome the deficiencies of existing phenotypic tests to identify C. auris and related species. PMID:28539346

Rapid and Accurate Molecular Identification of the Emerging Multidrug-Resistant Pathogen Candida auris.

PubMed

Kordalewska, Milena; Zhao, Yanan; Lockhart, Shawn R; Chowdhary, Anuradha; Berrio, Indira; Perlin, David S

2017-08-01

Candida auris is an emerging multidrug-resistant fungal pathogen causing nosocomial and invasive infections associated with high mortality. C. auris is commonly misidentified as several different yeast species by commercially available phenotypic identification platforms. Thus, there is an urgent need for a reliable diagnostic method. In this paper, we present fast, robust, easy-to-perform and interpret PCR and real-time PCR assays to identify C. auris and related species: Candida duobushaemulonii , Candida haemulonii , and Candida lusitaniae Targeting rDNA region nucleotide sequences, primers specific for C. auris only or C. auris and related species were designed. A panel of 140 clinical fungal isolates was used in both PCR and real-time PCR assays followed by electrophoresis or melting temperature analysis, respectively. The identification results from the assays were 100% concordant with DNA sequencing results. These molecular assays overcome the deficiencies of existing phenotypic tests to identify C. auris and related species. Copyright © 2017 Kordalewska et al.

Global Analysis of the Fungal Microbiome in Cystic Fibrosis Patients Reveals Loss of Function of the Transcriptional Repressor Nrg1 as a Mechanism of Pathogen Adaptation

PubMed Central

Kim, Sang Hu; Clark, Shawn T.; Surendra, Anuradha; Copeland, Julia K.; Wang, Pauline W.; Ammar, Ron; Collins, Cathy; Tullis, D. Elizabeth; Nislow, Corey; Hwang, David M.; Guttman, David S.; Cowen, Leah E.

2015-01-01

The microbiome shapes diverse facets of human biology and disease, with the importance of fungi only beginning to be appreciated. Microbial communities infiltrate diverse anatomical sites as with the respiratory tract of healthy humans and those with diseases such as cystic fibrosis, where chronic colonization and infection lead to clinical decline. Although fungi are frequently recovered from cystic fibrosis patient sputum samples and have been associated with deterioration of lung function, understanding of species and population dynamics remains in its infancy. Here, we coupled high-throughput sequencing of the ribosomal RNA internal transcribed spacer 1 (ITS1) with phenotypic and genotypic analyses of fungi from 89 sputum samples from 28 cystic fibrosis patients. Fungal communities defined by sequencing were concordant with those defined by culture-based analyses of 1,603 isolates from the same samples. Different patients harbored distinct fungal communities. There were detectable trends, however, including colonization with Candida and Aspergillus species, which was not perturbed by clinical exacerbation or treatment. We identified considerable inter- and intra-species phenotypic variation in traits important for host adaptation, including antifungal drug resistance and morphogenesis. While variation in drug resistance was largely between species, striking variation in morphogenesis emerged within Candida species. Filamentation was uncoupled from inducing cues in 28 Candida isolates recovered from six patients. The filamentous isolates were resistant to the filamentation-repressive effects of Pseudomonas aeruginosa, implicating inter-kingdom interactions as the selective force. Genome sequencing revealed that all but one of the filamentous isolates harbored mutations in the transcriptional repressor NRG1; such mutations were necessary and sufficient for the filamentous phenotype. Six independent nrg1 mutations arose in Candida isolates from different patients, providing a poignant example of parallel evolution. Together, this combined clinical-genomic approach provides a high-resolution portrait of the fungal microbiome of cystic fibrosis patient lungs and identifies a genetic basis of pathogen adaptation. PMID:26588216

Global Analysis of the Fungal Microbiome in Cystic Fibrosis Patients Reveals Loss of Function of the Transcriptional Repressor Nrg1 as a Mechanism of Pathogen Adaptation.

PubMed

Kim, Sang Hu; Clark, Shawn T; Surendra, Anuradha; Copeland, Julia K; Wang, Pauline W; Ammar, Ron; Collins, Cathy; Tullis, D Elizabeth; Nislow, Corey; Hwang, David M; Guttman, David S; Cowen, Leah E

2015-11-01

The microbiome shapes diverse facets of human biology and disease, with the importance of fungi only beginning to be appreciated. Microbial communities infiltrate diverse anatomical sites as with the respiratory tract of healthy humans and those with diseases such as cystic fibrosis, where chronic colonization and infection lead to clinical decline. Although fungi are frequently recovered from cystic fibrosis patient sputum samples and have been associated with deterioration of lung function, understanding of species and population dynamics remains in its infancy. Here, we coupled high-throughput sequencing of the ribosomal RNA internal transcribed spacer 1 (ITS1) with phenotypic and genotypic analyses of fungi from 89 sputum samples from 28 cystic fibrosis patients. Fungal communities defined by sequencing were concordant with those defined by culture-based analyses of 1,603 isolates from the same samples. Different patients harbored distinct fungal communities. There were detectable trends, however, including colonization with Candida and Aspergillus species, which was not perturbed by clinical exacerbation or treatment. We identified considerable inter- and intra-species phenotypic variation in traits important for host adaptation, including antifungal drug resistance and morphogenesis. While variation in drug resistance was largely between species, striking variation in morphogenesis emerged within Candida species. Filamentation was uncoupled from inducing cues in 28 Candida isolates recovered from six patients. The filamentous isolates were resistant to the filamentation-repressive effects of Pseudomonas aeruginosa, implicating inter-kingdom interactions as the selective force. Genome sequencing revealed that all but one of the filamentous isolates harbored mutations in the transcriptional repressor NRG1; such mutations were necessary and sufficient for the filamentous phenotype. Six independent nrg1 mutations arose in Candida isolates from different patients, providing a poignant example of parallel evolution. Together, this combined clinical-genomic approach provides a high-resolution portrait of the fungal microbiome of cystic fibrosis patient lungs and identifies a genetic basis of pathogen adaptation.

Oral Administration of the Broad-Spectrum Antibiofilm Compound Toremifene Inhibits Candida albicans and Staphylococcus aureus Biofilm Formation In Vivo

PubMed Central

De Cremer, Kaat; Delattin, Nicolas; De Brucker, Katrijn; Peeters, Annelies; Kucharíková, Soña; Gerits, Evelien; Verstraeten, Natalie; Michiels, Jan; Van Dijck, Patrick; Thevissen, Karin

2014-01-01

We here report on the in vitro activity of toremifene to inhibit biofilm formation of different fungal and bacterial pathogens, including Candida albicans, Candida glabrata, Candida dubliniensis, Candida krusei, Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis. We validated the in vivo efficacy of orally administered toremifene against C. albicans and S. aureus biofilm formation in a rat subcutaneous catheter model. Combined, our results demonstrate the potential of toremifene as a broad-spectrum oral antibiofilm compound. PMID:25288093

Effect of ferrocene-substituted porphyrin RL-91 on Candida albicans biofilm formation.

PubMed

Lippert, Rainer; Vojnovic, Sandra; Mitrovic, Aleksandra; Jux, Norbert; Ivanović-Burmazović, Ivana; Vasiljevic, Branka; Stankovic, Nada

2014-08-01

Ferrocene-substituted porphyrin RL-91 exhibits antifungal activity against opportune human pathogen Candida albicans. RL-91 efficiently inhibits growth of both planktonic C. albicans cells and cells within biofilms without photoactivation. The minimal inhibitory concentration for plankton form (PMIC) was established to be 100 μg/mL and the same concentration killed 80% of sessile cells in the mature biofilm (SMIC80). Furthermore PMIC of RL-91 efficiently prevents C. albicans biofilm formation. RL-91 is cytotoxic for human fibroblasts in vitro in concentration of 10 μg/mL, however it does not cause hemolysis in concentrations of up to 50 μg/mL. These findings open possibility for application of RL-91 as an antifungal agent for external antibiofilm treatment of medical devices as well as a scaffold for further development of porphyrin based systemic antifungals. Copyright © 2014 Elsevier Ltd. All rights reserved.

Assessment of herbal drugs for promising anti-Candida activity.

PubMed

Soliman, Sameh S M; Semreen, Mohammad H; El-Keblawy, Ali A; Abdullah, Arbab; Uppuluri, Priya; Ibrahim, Ashraf S

2017-05-08

Microbial infections are diverse and cause serious human diseases. Candida albicans infections are serious healthcare-related infections that are complicated by its morphological switching from yeast to hyphae, resistant biofilm formation and mixed infections with bacteria. Due to the increase in drug resistance to currently used antimicrobial agents and the presence of undesirable side effects, the need for safe and effective novel therapies is important. Compounds derived from plants are known for their medicinal properties including antimicrobial activities. The purpose of the study was to compare and evaluate the anti-Candida activities of several medicinal plants in order for the selection of a herbal drug for human use as effective antimicrobial. The selection was taking into considerations two important parameters; parameters related to the selected drug including activity, stability, solubility and toxicity and parameters related to the pathogen including its different dynamic growth and its accompanied secondary bacterial infections. Seven different plants including Avicennia marina (Qurm), Fagonia indica (Shoka'a), Lawsania inermis (Henna), Portulaca oleracea (Baq'lah), Salvadora persica (Souwak), Ziziphus spina- Christi (Sidr) and Asphodelus tenuifolius (Kufer) were ground and extracted with ethanol. The ethanol extracts were evaporated and the residual extract dissolved in water prior to testing against Candida albicans in its different morphologies. The antibacterial and cytotoxic effects of the plants extracts were also tested. Out of the seven tested plants, L. inermis and P. oleracea showed significant anti-Candida activity with MIC ~10 μg/mL. Furthermore, both plant extracts were able to inhibit C. albicans growth at its dynamic growth phases including biofilm formation and age resistance. Accompanied secondary bacterial infections can complicate Candida pathogenesis. L. inermis and P. oleracea extracts showed effective antibacterial activities against S. aureus, P. aeruginosa, E. coli, and the multidrug resistant (MDR) A. baumannii and Klebsiella pneumoniae. Both extracts showed no toxicity when measured at their MIC on human erythrocytes. The results from this study suggested that L. inermis and P. oleracea extracts and/or their chemicals are likely to be promising drugs for human use against C. albicans and MDR bacteria.

Ras-Mediated Signal Transduction and Virulence in Human Pathogenic Fungi

PubMed Central

Fortwendel, Jarrod R.

2013-01-01

Signal transduction pathways regulating growth and stress responses are areas of significant study in the effort to delineate pathogenic mechanisms of fungi. In-depth knowledge of signal transduction events deepens our understanding of how a fungal pathogen is able to sense changes in the environment and respond accordingly by modulation of gene expression and re-organization of cellular activities to optimize fitness. Members of the Ras protein family are important regulators of growth and differentiation in eukaryotic organisms, and have been the focus of numerous studies exploring fungal pathogenesis. Here, the current data regarding Ras signal transduction are reviewed for three major pathogenic fungi: Cryptococcus neoformans, Candida albicans and Aspergillus fumigatus. Particular emphasis is placed on Ras-protein interactions during control of morphogenesis, stress response and virulence. PMID:24855584

PgTeL, the lectin found in Punica granatum juice, is an antifungal agent against Candida albicans and Candida krusei.

PubMed

da Silva, Pollyanna Michelle; de Moura, Maiara Celine; Gomes, Francis Soares; da Silva Trentin, Danielle; Silva de Oliveira, Ana Patrícia; de Mello, Gabriela Souto Vieira; da Rocha Pitta, Maira Galdino; de Melo Rego, Moacyr Jesus Barreto; Coelho, Luana Cassandra Breitenbach Barroso; Macedo, Alexandre José; de Figueiredo, Regina Celia Bressan Queiroz; Paiva, Patrícia Maria Guedes; Napoleão, Thiago Henrique

2018-03-01

The pomegranate (Punica granatum) sarcotesta contains a chitin-binding lectin (PgTeL) with antibacterial activity against human pathogenic species. In this work, the structural stability of PgTeL was evaluated by fluorimetric analysis and the lectin was evaluated for cytotoxicity to human peripheral blood mononuclear cells (PBMCs) and antifungal activity against Candida albicans and Candida krusei. PgTeL folding was impaired when lectin was incubated at pH≥6.0. On the other hand, the lectin did not undergo unfolding even when heated at 100°C. PgTeL (1, 10, and 100μg/mL) was not cytotoxic to PBMCs. Antifungal activity was detected for C. albicans (MIC: 25μg/mL; MFC: 50μg/mL) and C. krusei (MIC and MFC of 12.5μg/mL). Treatment of yeast cells with PgTeL resulted in decrease of intracellular ATP content even at sub-inhibitory concentrations (½MIC and ¼MIC) and induced lipid peroxidation. In addition, PgTeL damaged the integrity of fungal cell wall of both species, with more pronounced effects in C. krusei. The lectin showed significant antibiofilm activity on C. albicans at sub-inhibitory concentrations (0.195 and 0.39μg/mL). In conclusion, PgTeL is an anti-Candida agent whose action mechanism involves oxidative stress, energetic collapse, damage to the cell wall and rupture of yeast cells. Copyright © 2017 Elsevier B.V. All rights reserved.

Pathogenic Fungi Regulate Immunity by Inducing Neutrophilic Myeloid-Derived Suppressor Cells

PubMed Central

Rieber, Nikolaus; Singh, Anurag; Öz, Hasan; Carevic, Melanie; Bouzani, Maria; Amich, Jorge; Ost, Michael; Ye, Zhiyong; Ballbach, Marlene; Schäfer, Iris; Mezger, Markus; Klimosch, Sascha N.; Weber, Alexander N.R.; Handgretinger, Rupert; Krappmann, Sven; Liese, Johannes; Engeholm, Maik; Schüle, Rebecca; Salih, Helmut Rainer; Marodi, Laszlo; Speckmann, Carsten; Grimbacher, Bodo; Ruland, Jürgen; Brown, Gordon D.; Beilhack, Andreas; Loeffler, Juergen; Hartl, Dominik

2015-01-01

Summary Despite continuous contact with fungi, immunocompetent individuals rarely develop pro-inflammatory antifungal immune responses. The underlying tolerogenic mechanisms are incompletely understood. Using both mouse models and human patients, we show that infection with the human pathogenic fungi Aspergillus fumigatus and Candida albicans induces a distinct subset of neutrophilic myeloid-derived suppressor cells (MDSCs), which functionally suppress T and NK cell responses. Mechanistically, pathogenic fungi induce neutrophilic MDSCs through the pattern recognition receptor Dectin-1 and its downstream adaptor protein CARD9. Fungal MDSC induction is further dependent on pathways downstream of Dectin-1 signaling, notably reactive oxygen species (ROS) generation as well as caspase-8 activity and interleukin-1 (IL-1) production. Additionally, exogenous IL-1β induces MDSCs to comparable levels observed during C. albicans infection. Adoptive transfer and survival experiments show that MDSCs are protective during invasive C. albicans infection, but not A. fumigatus infection. These studies define an innate immune mechanism by which pathogenic fungi regulate host defense. PMID:25771792

Fungi that Infect Humans.

PubMed

Köhler, Julia R; Hube, Bernhard; Puccia, Rosana; Casadevall, Arturo; Perfect, John R

2017-06-01

Fungi must meet four criteria to infect humans: growth at human body temperatures, circumvention or penetration of surface barriers, lysis and absorption of tissue, and resistance to immune defenses, including elevated body temperatures. Morphogenesis between small round, detachable cells and long, connected cells is the mechanism by which fungi solve problems of locomotion around or through host barriers. Secretion of lytic enzymes, and uptake systems for the released nutrients, are necessary if a fungus is to nutritionally utilize human tissue. Last, the potent human immune system evolved in the interaction with potential fungal pathogens, so few fungi meet all four conditions for a healthy human host. Paradoxically, the advances of modern medicine have made millions of people newly susceptible to fungal infections by disrupting immune defenses. This article explores how different members of four fungal phyla use different strategies to fulfill the four criteria to infect humans: the Entomophthorales, the Mucorales, the Ascomycota, and the Basidiomycota. Unique traits confer human pathogenic potential on various important members of these phyla: pathogenic Onygenales comprising thermal dimorphs such as Histoplasma and Coccidioides ; the Cryptococcus spp. that infect immunocompromised as well as healthy humans; and important pathogens of immunocompromised patients- Candida , Pneumocystis , and Aspergillus spp. Also discussed are agents of neglected tropical diseases important in global health such as mycetoma and paracoccidiomycosis and common pathogens rarely implicated in serious illness such as dermatophytes. Commensalism is considered, as well as parasitism, in shaping genomes and physiological systems of hosts and fungi during evolution.

Challenges and Strategies for Proteome Analysis of the Interaction of Human Pathogenic Fungi with Host Immune Cells.

PubMed

Krüger, Thomas; Luo, Ting; Schmidt, Hella; Shopova, Iordana; Kniemeyer, Olaf

2015-12-14

Opportunistic human pathogenic fungi including the saprotrophic mold Aspergillus fumigatus and the human commensal Candida albicans can cause severe fungal infections in immunocompromised or critically ill patients. The first line of defense against opportunistic fungal pathogens is the innate immune system. Phagocytes such as macrophages, neutrophils and dendritic cells are an important pillar of the innate immune response and have evolved versatile defense strategies against microbial pathogens. On the other hand, human-pathogenic fungi have sophisticated virulence strategies to counteract the innate immune defense. In this context, proteomic approaches can provide deeper insights into the molecular mechanisms of the interaction of host immune cells with fungal pathogens. This is crucial for the identification of both diagnostic biomarkers for fungal infections and therapeutic targets. Studying host-fungal interactions at the protein level is a challenging endeavor, yet there are few studies that have been undertaken. This review draws attention to proteomic techniques and their application to fungal pathogens and to challenges, difficulties, and limitations that may arise in the course of simultaneous dual proteome analysis of host immune cells interacting with diverse morphotypes of fungal pathogens. On this basis, we discuss strategies to overcome these multifaceted experimental and analytical challenges including the viability of immune cells during co-cultivation, the increased and heterogeneous protein complexity of the host proteome dynamically interacting with the fungal proteome, and the demands on normalization strategies in terms of relative quantitative proteome analysis.

Evolution of pathogenicity and sexual reproduction in eight Candida genomes

PubMed Central

Butler, Geraldine; Rasmussen, Matthew D.; Lin, Michael F.; Santos, Manuel A.S.; Sakthikumar, Sharadha; Munro, Carol A.; Rheinbay, Esther; Grabherr, Manfred; Forche, Anja; Reedy, Jennifer L.; Agrafioti, Ino; Arnaud, Martha B.; Bates, Steven; Brown, Alistair J.P.; Brunke, Sascha; Costanzo, Maria C.; Fitzpatrick, David A.; de Groot, Piet W. J.; Harris, David; Hoyer, Lois L.; Hube, Bernhard; Klis, Frans M.; Kodira, Chinnappa; Lennard, Nicola; Logue, Mary E.; Martin, Ronny; Neiman, Aaron M.; Nikolaou, Elissavet; Quail, Michael A.; Quinn, Janet; Santos, Maria C.; Schmitzberger, Florian F.; Sherlock, Gavin; Shah, Prachi; Silverstein, Kevin; Skrzypek, Marek S.; Soll, David; Staggs, Rodney; Stansfield, Ian; Stumpf, Michael P H; Sudbery, Peter E.; Thyagarajan, Srikantha; Zeng, Qiandong; Berman, Judith; Berriman, Matthew; Heitman, Joseph; Gow, Neil A. R.; Lorenz, Michael C.; Birren, Bruce W.; Kellis, Manolis; Cuomo, Christina A.

2009-01-01

Candida species are the most common cause of opportunistic fungal infection worldwide. We report the genome sequences of six Candida species and compare these and related pathogens and nonpathogens. There are significant expansions of cell wall, secreted, and transporter gene families in pathogenic species, suggesting adaptations associated with virulence. Large genomic tracts are homozygous in three diploid species, possibly resulting from recent recombination events. Surprisingly, key components of the mating and meiosis pathways are missing from several species. These include major differences at the Mating-type loci (MTL); Lodderomyces elongisporus lacks MTL, and components of the a1/alpha2 cell identity determinant were lost in other species, raising questions about how mating and cell types are controlled. Analysis of the CUG leucine to serine genetic code change reveals that 99% of ancestral CUG codons were erased and new ones arose elsewhere. Lastly, we revise the C. albicans gene catalog, identifying many new genes. PMID:19465905

Peptides of the Constant Region of Antibodies Display Fungicidal Activity

PubMed Central

Polonelli, Luciano; Ciociola, Tecla; Magliani, Walter; Zanello, Pier Paolo; D'Adda, Tiziana; Galati, Serena; De Bernardis, Flavia; Arancia, Silvia; Gabrielli, Elena; Pericolini, Eva; Vecchiarelli, Anna; Arruda, Denise C.; Pinto, Marcia R.; Travassos, Luiz R.; Pertinhez, Thelma A.; Spisni, Alberto; Conti, Stefania

2012-01-01

Synthetic peptides with sequences identical to fragments of the constant region of different classes (IgG, IgM, IgA) of antibodies (Fc-peptides) exerted a fungicidal activity in vitro against pathogenic yeasts, such as Candida albicans, Candida glabrata, Cryptococcus neoformans, and Malassezia furfur, including caspofungin and triazole resistant strains. Alanine-substituted derivatives of fungicidal Fc-peptides, tested to evaluate the critical role of each residue, displayed unaltered, increased or decreased candidacidal activity in vitro. An Fc-peptide, included in all human IgGs, displayed a therapeutic effect against experimental mucosal and systemic candidiasis in mouse models. It is intriguing to hypothesize that some Fc-peptides may influence the antifungal immune response and constitute the basis for devising new antifungal agents. PMID:22470523

Cell wall proteome of pathogenic fungi.

PubMed

Karkowska-Kuleta, Justyna; Kozik, Andrzej

2015-01-01

A fast development of a wide variety of proteomic techniques supported by mass spectrometry coupled with high performance liquid chromatography has been observed in recent years. It significantly contributes to the progress in research on the cell wall, very important part of the cells of pathogenic fungi. This complicated structure composed of different polysaccharides, proteins, lipids and melanin, plays a key role in interactions with the host during infection. Changes in the set of the surface-exposed proteins under different environmental conditions provide an effective way for pathogens to respond, adapt and survive in the new niches of infection. This work summarizes the current state of knowledge on proteins, studied both qualitatively and quantitatively, and found within the cell wall of fungal pathogens for humans, including Candida albicans, Candida glabrata, Aspergillus fumigatus, Cryptococcus neoformans and other medically important fungi. The described proteomic studies involved the isolation and fractionation of particular sets of proteins of interest with various techniques, often based on differences in their linkages to the polysaccharide scaffold. Furthermore, the proteinaceous contents of extracellular vesicles ("virulence bags") of C. albicans, C. neoformans, Histoplasma capsulatum and Paracoccidioides brasiliensis are compared, because their production can partially explain the problem of non-classical protein secretion by fungi. The role assigned to surface-exposed proteins in pathogenesis of fungal infections is enormously high, thus justifying the need for further investigation of cell wall proteomes.

Candida tropicalis from veterinary and human sources shows similar in vitro hemolytic activity, antifungal biofilm susceptibility and pathogenesis against Caenorhabditis elegans.

PubMed

Brilhante, Raimunda Sâmia Nogueira; Oliveira, Jonathas Sales de; Evangelista, Antônio José de Jesus; Serpa, Rosana; Silva, Aline Lobão da; Aguiar, Felipe Rodrigues Magalhães de; Pereira, Vandbergue Santos; Castelo-Branco, Débora de Souza Collares Maia; Pereira-Neto, Waldemiro Aquino; Cordeiro, Rossana de Aguiar; Sidrim, José Júlio Costa; Rocha, Marcos Fábio Gadelha

2016-08-30

The aim of this study was to evaluate the in vitro hemolytic activity and biofilm antifungal susceptibility of veterinary and human Candida tropicalis strains, as well as their pathogenesis against Caenorhabditis elegans. Twenty veterinary isolates and 20 human clinical isolates of C. tropicalis were used. The strains were evaluated for their hemolytic activity and biofilm production. Biofilm susceptibility to itraconazole, fluconazole, voriconazole, amphotericin B and caspofungin was assessed using broth microdilution assay. The in vivo evaluation of strain pathogenicity was investigated using the nematode C. elegans. Hemolytic factor was observed in 95% of the strains and 97.5% of the isolates showed ability to form biofilm. Caspofungin and amphotericin B showed better results than azole antifungals against mature biofilms. Paradoxical effect on mature biofilm metabolic activity was observed at elevated concentrations of caspofungin (8-64μg/mL). Azole antifungals were not able to inhibit mature C. tropicalis biofilms, even at the higher tested concentrations. High mortality rates of C. elegans were observed when the worms were exposed to with C. tropicalis strains, reaching up to 96%, 96h after exposure of the worms to C. tropicalis strains. These results reinforce the high pathogenicity of C. tropicalis from veterinary and human sources and show the effectiveness of caspofungin and amphotericin B against mature biofilms of this species. Copyright © 2016 Elsevier B.V. All rights reserved.

Host response to Candida albicans bloodstream infection and sepsis

PubMed Central

Duggan, Seána; Leonhardt, Ines; Hünniger, Kerstin; Kurzai, Oliver

2015-01-01

Candida albicans is a major cause of bloodstream infection which may present as sepsis and septic shock - major causes of morbidity and mortality world-wide. After invasion of the pathogen, innate mechanisms govern the early response. Here, we outline the models used to study these mechanisms and summarize our current understanding of innate immune responses during Candida bloodstream infection. This includes protective immunity as well as harmful responses resulting in Candida induced sepsis. Neutrophilic granulocytes are considered principal effector cells conferring protection and recognize C. albicans mainly via complement receptor 3. They possess a range of effector mechanisms, contributing to elimination of the pathogen. Neutrophil activation is closely linked to complement and modulated by activated mononuclear cells. A thorough understanding of these mechanisms will help in creating an individualized approach to patients suffering from systemic candidiasis and aid in optimizing clinical management. PMID:25785541

Donor Derived Candida stellimalicola in a Clinical Specimen: Preservation Fluid Contamination During Pancreas Procurement.

PubMed

Dupont, Damien; Huguenin, Antoine; Tisserand, Elodie; Reiter, Véronique; Morelon, Emmanuel; Badet, Lionel; Villena, Isabelle; Wallon, Martine; Toubas, Dominique

2018-06-01

We report here a case of possible donor-derived Candida stellimalicola infection after pancreas transplantation. Candida stellimalicola, an environmental non-filamentous yeast, was isolated from both the peritoneal fluid of the graft donor and the preservation fluid of the transplanted pancreas. Interestingly, this strain exhibited high minimum inhibitory concentrations to azoles. These results justified the use of echinocandins as therapy instead of fluconazole. This switch permitted a favorable outcome. To our knowledge, this is the first report of C. stellimalicola from clinical samples and therefore the first reported case of a possible human infection. This case report highlights the need for standardized microbiological procedures in solid organ transplant settings. Moreover, it underlines the importance of using molecular identification technique when routine techniques do not allow successful identification of the pathogen. It is of utmost importance to determine sensitivity profile, even in the absence of species-level identification, because resistance to fluconazole is not uncommon, especially in emergent species.

Candida utilis and Cyberlindnera (Pichia) jadinii: yeast relatives with expanding applications.

PubMed

Buerth, Christoph; Tielker, Denis; Ernst, Joachim F

2016-08-01

The yeast Candida utilis is used as a food additive and as a host for heterologous gene expression to produce various metabolites and proteins. Reliable protocols for intracellular production of recombinant proteins are available for C. utilis and have now been expanded to secrete proteins into the growth medium or to achieve surface display by linkage to a cell wall protein. A recombinant C. utilis strain was recently shown to induce oral tolerance in a mouse model of multiple sclerosis suggesting future applications in autoimmune therapy. Whole genome sequencing of C. utilis and its presumed parent Cyberlindnera (Pichia) jadinii demonstrated different ploidy but high sequence identity, consistent with identical recombinant technologies for both yeasts. C. jadinii was recently described as an antagonist to the important human fungal pathogen Candida albicans suggesting its use as a probiotic agent. The review summarizes the status of recombinant protein production in C. utilis, as well as current and future biotechnological and medical applications of C. utilis and C. jadinii.

The mating type-like loci of Candida glabrata.

PubMed

Yáñez-Carrillo, Patricia; Robledo-Márquez, Karina A; Ramírez-Zavaleta, Candy Y; De Las Peñas, Alejandro; Castaño, Irene

2014-01-01

Candida glabrata, a haploid and opportunistic fungal pathogen that has not known sexual cycle, has conserved the majority of the genes required for mating and cell type identity. The C. glabrata genome contains three mating-type-like loci called MTL1, MTL2 and MTL3. The three loci encode putative transcription factors, a1, α1 and α2 that regulate cell type identity and sexual reproduction in other fungi like the closely related Saccharomyces cerevisiae. MTL1 can contain either a or α information. MTL2, which contains a information and MTL3 with α information, are relatively close to two telomeres. MTL1 and MTL2 are transcriptionally active, while MTL3 is subject to an incomplete silencing nucleated at the telomere that depends on the silencing proteins Sir2, Sir3, Sir4, yKu70/80, Rif1, Rap1 and Sum1. C. glabrata does not seem to maintain cell type identity, as cell type-specific genes are expressed regardless of the type (or even absence) of mating information. These data highlight important differences in the control of mating and cell type identity between the non-pathogenic yeast S. cerevisiae and C. glabrata, which might explain the absence of a sexual cycle in C. glabrata. The fact that C. glabrata has conserved the vast majority of the genes involved in mating might suggest that some of these genes perhaps have been rewired to control other processes important for the survival inside the host as a commensal or as a human pathogen. This manuscript is part of the series of works presented at the "V International Workshop: Molecular genetic approaches to the study of human pathogenic fungi" (Oaxaca, Mexico, 2012). Copyright © 2013 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

Identification of proteins involved in the adhesionof Candida species to different medical devices.

PubMed

Núñez-Beltrán, Arianna; López-Romero, Everardo; Cuéllar-Cruz, Mayra

2017-06-01

Adhesion is the first step for Candida species to form biofilms on medical devices implanted in the human host. Both the physicochemical nature of the biomaterial and cell wall proteins (CWP) of the pathogen play a determinant role in the process. While it is true that some CWP have been identified in vitro, little is known about the CWP of pathogenic species of Candida involved in adhesion. On this background, we considered it important to investigate the potential role of CWP of C. albicans, C. glabrata, C. krusei and C. parapsilosis in adhesion to different medical devices. Our results indicate that the four species strongly adher to polyvinyl chloride (PVC) devices, followed by polyurethane and finally by silicone. It was interesting to identify fructose-bisphosphate aldolase (Fba1) and enolase 1 (Eno1) as the CWP involved in adhesion of C. albicans, C. glabrata and C. krusei to PVC devices whereas phosphoglycerate kinase (Pgk) and Eno1 allow C. parapsilosis to adher to silicone-made implants. Results presented here suggest that these CWP participate in the initial event of adhesion and are probably followed by other proteins that covalently bind to the biomaterial thus providing conditions for biofilm formation and eventually the onset of infection. Copyright © 2017 Elsevier Ltd. All rights reserved.

Signaling through protein kinases and transcriptional regulators in Candida albicans.

PubMed

Dhillon, Navneet K; Sharma, Sadhna; Khuller, G K

2003-01-01

The human fungal pathogen Candida albicans switches from a budding yeast form to a polarized hyphal form in response to various external signals. This morphogenetic switching has been implicated in the development of pathogenicity. Several signaling pathways that regulate morphogenesis have been identified, including various transcription factors that either activate or repress hypha-specific genes. Two well-characterized pathways include the MAP kinase cascade and cAMP-dependent protein kinase pathway that regulate the transcription factors Cph1p and Efg1p, respectively. cAMP also appears to interplay with other second messengers: Ca2+, inositol tri-phosphates in regulating yeast-hyphal transition. Other, less-characterized pathways include two component histidine kinases, cyclin-dependent kinase pathway, and condition specific pathways such as pH and embedded growth conditions. Nrg1 and Rfg1 function as transcriptional repressors of hyphal genes via recruitment of Tup1 co-repressor complex. Different upstream signals converge into a common downstream output during hyphal switch. The levels of expression of several genes have been shown to be associated with hyphal morphogenesis rather than with a specific hypha-inducing condition. Hyphal development is also linked to the expression of a range of other virulence factors. This review explains the relative contribution of multiple pathways that could be used by Candida albican cells to sense subtle differences in the growth conditions of its native host environment.

Repeat-Associated Fission Yeast-Like Regional Centromeres in the Ascomycetous Budding Yeast Candida tropicalis

PubMed Central

Chatterjee, Gautam; Sankaranarayanan, Sundar Ram; Guin, Krishnendu; Thattikota, Yogitha; Padmanabhan, Sreedevi; Siddharthan, Rahul; Sanyal, Kaustuv

2016-01-01

The centromere, on which kinetochore proteins assemble, ensures precise chromosome segregation. Centromeres are largely specified by the histone H3 variant CENP-A (also known as Cse4 in yeasts). Structurally, centromere DNA sequences are highly diverse in nature. However, the evolutionary consequence of these structural diversities on de novo CENP-A chromatin formation remains elusive. Here, we report the identification of centromeres, as the binding sites of four evolutionarily conserved kinetochore proteins, in the human pathogenic budding yeast Candida tropicalis. Each of the seven centromeres comprises a 2 to 5 kb non-repetitive mid core flanked by 2 to 5 kb inverted repeats. The repeat-associated centromeres of C. tropicalis all share a high degree of sequence conservation with each other and are strikingly diverged from the unique and mostly non-repetitive centromeres of related Candida species—Candida albicans, Candida dubliniensis, and Candida lusitaniae. Using a plasmid-based assay, we further demonstrate that pericentric inverted repeats and the underlying DNA sequence provide a structural determinant in CENP-A recruitment in C. tropicalis, as opposed to epigenetically regulated CENP-A loading at centromeres in C. albicans. Thus, the centromere structure and its influence on de novo CENP-A recruitment has been significantly rewired in closely related Candida species. Strikingly, the centromere structural properties along with role of pericentric repeats in de novo CENP-A loading in C. tropicalis are more reminiscent to those of the distantly related fission yeast Schizosaccharomyces pombe. Taken together, we demonstrate, for the first time, fission yeast-like repeat-associated centromeres in an ascomycetous budding yeast. PMID:26845548

Effect of serine-type protease of Candida spp. isolated from linear gingival erythema of HIV-positive children: critical factors in the colonization.

PubMed

Portela, Maristela B; Souza, Ivete P R; Abreu, Celina M; Bertolini, Martinna; Holandino, Carla; Alviano, Celuta S; Santos, André L S; Soares, Rosangela M A

2010-11-01

  There are several kinds of oral soft tissue lesions that are common manifestations observed in human immunodeficiency virus (HIV)-infected children; for example, linear gingival erythema (LGE) that is a distinctive fiery red band along the margin of the gingivae. The etiology and pathogenesis of LGE are questionable, but a candidal origin has been suggested. Proteases are key virulence attributes produced by a variety of pathogenic fungi, including Candida. The objective of the present study is to identify the protease production in Candida species including, C. albicans (n=5), C. dubliniensis (n=1) and C. tropicalis (n=1), isolated directly from typical LGE lesions observed in six HIV-positive children, and also to test the effect of a serine protease inhibitor on the interaction of Candida spp. and epithelial cells in vitro. The ability of Candida strains to release proteases in the culture supernatant fluids was visualized by gelatin-SDS-PAGE. Gel strips containing 30-fold concentrated supernatant (1.5×10(8) yeasts) were incubated at 37°C for 48 h in 50 mM sodium phosphate buffer, pH 5.5. The concentrated supernatants were also incubated with fibronectin, laminin, immunoglobulin G, bovine serum albumin and human serum albumin. The effect of serine protease inhibitor on the interaction of Candida spp. and epithelial cells (MA 104) was measured after pre-treatment of fungi with the inhibitor (phenylmethylsulphonyl fluoride, PMSF). All the extracellular proteases were completely inhibited by PMSF, identifying these activities as serine-type proteases. Interestingly, a common 62-kDa serine protease was observed in all Candida strains. The culture supernatants, rich in serine protease activities, cleaved several soluble proteinaceous substrates. Additionally, we demonstrated that pre-treatment of C. albicans, C. dubliniensis and C. tropicalis with PMSF diminished the interaction with epithelial cells. Collectively, our results show that Candida spp. isolated from LGE lesions produced and secreted serine proteases and these enzymes may be involved in the initial colonization events. © 2010 John Wiley & Sons A/S.

Candida albicans Chitin Increases Arginase-1 Activity in Human Macrophages, with an Impact on Macrophage Antimicrobial Functions

PubMed Central

MacCallum, Donna M.; Brown, Gordon D.

2017-01-01

ABSTRACT   The opportunistic human fungal pathogen Candida albicans can cause a variety of diseases, ranging from superficial mucosal infections to life-threatening systemic infections. Phagocytic cells of the innate immune response, such as neutrophils and macrophages, are important first-line responders to an infection and generate reactive oxygen and nitrogen species as part of their protective antimicrobial response. During an infection, host cells generate nitric oxide through the enzyme inducible nitric oxide synthase (iNOS) to kill the invading pathogen. Inside the phagocyte, iNOS competes with the enzyme arginase-1 for a common substrate, the amino acid l-arginine. Several pathogenic species, including bacteria and parasitic protozoans, actively modulate the production of nitric oxide by inducing their own arginases or the host’s arginase activity to prevent the conversion of l-arginine to nitric oxide. We report here that C. albicans blocks nitric oxide production in human-monocyte-derived macrophages by induction of host arginase activity. We further determined that purified chitin (a fungal cell wall polysaccharide) and increased chitin exposure at the fungal cell wall surface induces this host arginase activity. Blocking the C. albicans-induced arginase activity with the arginase-specific substrate inhibitor Nω-hydroxy-nor-arginine (nor-NOHA) or the chitinase inhibitor bisdionin F restored nitric oxide production and increased the efficiency of fungal killing. Moreover, we determined that C. albicans influences macrophage polarization from a classically activated phenotype toward an alternatively activated phenotype, thereby reducing antimicrobial functions and mediating fungal survival. Therefore, C. albicans modulates l-arginine metabolism in macrophages during an infection, potentiating its own survival. PMID:28119468

Assessing the advantage of morphological changes in Candida albicans: a game theoretical study

PubMed Central

Tyc, Katarzyna M.; Kühn, Clemens; Wilson, Duncan; Klipp, Edda

2014-01-01

A range of attributes determines the virulence of human pathogens. During interactions with their hosts, pathogenic microbes often undergo transitions between distinct stages, and the ability to switch between these can be directly related to the disease process. Understanding the mechanisms and dynamics of these transitions is a key factor in understanding and combating infectious diseases. The human fungal pathogen Candida albicans exhibits different morphotypes at different stages during the course of infection (candidiasis). For example, hyphae are considered to be the invasive form, which causes tissue damage, while yeast cells are predominant in the commensal stage. Here, we described interactions of C. albicans with its human host in a game theoretic model. In the game, players are fungal cells. Each fungal cell can adopt one of the two strategies: to exist as a yeast or hyphal cell. We characterized the ranges of model parameters in which the coexistence of both yeast and hyphal forms is plausible. Stability analysis of the system showed that, in theory, a reduced ability of the host to specifically recognize yeast and hyphal cells can result in bi-stability of the microbial populations' profile. Inspired by the model analysis we reasoned that the types of microbial interactions can change during invasive candidiasis. We found that positive cooperation among fungal cells occurs in mild infections and an enhanced tendency to invade the host is associated with negative cooperation. The model can easily be extended to multi-player systems with direct application to identifying individuals that enhance either positive or negative cooperation. Results of the modeling approach have potential application in developing treatment strategies. PMID:24567730

Models hosts for the study of oral candidiasis.

PubMed

Junqueira, Juliana Campos

2012-01-01

Oral candidiasis is an opportunistic infection caused by yeast of the Candida genus, primarily Candida albicans. It is generally associated with predisposing factors such as the use of immunosuppressive agents, antibiotics, prostheses, and xerostomia. The development of research in animal models is extremely important for understanding the nature of the fungal pathogenicity, host interactions, and treatment of oral mucosal Candida infections. Many oral candidiasis models in rats and mice have been developed with antibiotic administration, induction of xerostomia, treatment with immunosuppressive agents, or the use of germ-free animals, and all these models has both benefits and limitations. Over the past decade, invertebrate model hosts, including Galleria mellonella, Caenorhabditis elegans, and Drosophila melanogaster, have been used for the study of Candida pathogenesis. These invertebrate systems offer a number of advantages over mammalian vertebrate models, predominantly because they allow the study of strain collections without the ethical considerations associated with studies in mammals. Thus, the invertebrate models may be useful to understanding of pathogenicity of Candida isolates from the oral cavity, interactions of oral microorganisms, and study of new antifungal compounds for oral candidiasis.

Candida albicans Pathogenesis: Fitting within the Host-Microbe Damage Response Framework

PubMed Central

Kong, Eric F.; Tsui, Christina; Nguyen, M. Hong; Clancy, Cornelius J.; Fidel, Paul L.; Noverr, Mairi

2016-01-01

Historically, the nature and extent of host damage by a microbe were considered highly dependent on virulence attributes of the microbe. However, it has become clear that disease is a complex outcome which can arise because of pathogen-mediated damage, host-mediated damage, or both, with active participation from the host microbiota. This awareness led to the formulation of the damage response framework (DRF), a revolutionary concept that defined microbial virulence as a function of host immunity. The DRF outlines six classifications of host damage outcomes based on the microbe and the strength of the immune response. In this review, we revisit this concept from the perspective of Candida albicans, a microbial pathogen uniquely adapted to its human host. This fungus commonly colonizes various anatomical sites without causing notable damage. However, depending on environmental conditions, a diverse array of diseases may occur, ranging from mucosal to invasive systemic infections resulting in microbe-mediated and/or host-mediated damage. Remarkably, C. albicans infections can fit into all six DRF classifications, depending on the anatomical site and associated host immune response. Here, we highlight some of these diverse and site-specific diseases and how they fit the DRF classifications, and we describe the animal models available to uncover pathogenic mechanisms and related host immune responses. PMID:27430274

Relationship between the Antifungal Susceptibility Profile and the Production of Virulence-Related Hydrolytic Enzymes in Brazilian Clinical Strains of Candida glabrata

PubMed Central

de Oliveira, Jean Carlos Almeida

2017-01-01

Candida glabrata is a facultative intracellular opportunistic fungal pathogen in human infections. Several virulence-associated attributes are involved in its pathogenesis, host-pathogen interactions, modulation of host immune defenses, and regulation of antifungal drug resistance. This study evaluated the in vitro antifungal susceptibility profile to five antifungal agents, the production of seven hydrolytic enzymes related to virulence, and the relationship between these phenotypes in 91 clinical strains of C. glabrata. All C. glabrata strains were susceptible to flucytosine. However, some of these strains showed resistance to amphotericin B (9.9%), fluconazole (15.4%), itraconazole (5.5%), or micafungin (15.4%). Overall, C. glabrata strains were good producers of catalase, aspartic protease, esterase, phytase, and hemolysin. However, caseinase and phospholipase in vitro activities were not detected. Statistically significant correlations were identified between micafungin minimum inhibitory concentration (MIC) and esterase production, between fluconazole and micafungin MIC and hemolytic activity, and between amphotericin B MIC and phytase production. These results contribute to clarify some of the C. glabrata mechanisms of pathogenicity. Moreover, the association between some virulence attributes and the regulation of antifungal resistance encourage the development of new therapeutic strategies involving virulence mechanisms as potential targets for effective antifungal drug development for the treatment of C. glabrata infections. PMID:28814823

Yeast cell differentiation: Lessons from pathogenic and non-pathogenic yeasts.

PubMed

Palková, Zdena; Váchová, Libuše

2016-09-01

Yeasts, historically considered to be single-cell organisms, are able to activate different differentiation processes. Individual yeast cells can change their life-styles by processes of phenotypic switching such as the switch from yeast-shaped cells to filamentous cells (pseudohyphae or true hyphae) and the transition among opaque, white and gray cell-types. Yeasts can also create organized multicellular structures such as colonies and biofilms, and the latter are often observed as contaminants on surfaces in industry and medical care and are formed during infections of the human body. Multicellular structures are formed mostly of stationary-phase or slow-growing cells that diversify into specific cell subpopulations that have unique metabolic properties and can fulfill specific tasks. In addition to the development of multiple protective mechanisms, processes of metabolic reprogramming that reflect a changed environment help differentiated individual cells and/or community cell constituents to survive harmful environmental attacks and/or to escape the host immune system. This review aims to provide an overview of differentiation processes so far identified in individual yeast cells as well as in multicellular communities of yeast pathogens of the Candida and Cryptococcus spp. and the Candida albicans close relative, Saccharomyces cerevisiae. Molecular mechanisms and extracellular signals potentially involved in differentiation processes are also briefly mentioned. Copyright © 2016 Elsevier Ltd. All rights reserved.

Candida parapsilosis Protects Premature Intestinal Epithelial Cells from Invasion and Damage by Candida albicans

PubMed Central

Gonia, Sara; Archambault, Linda; Shevik, Margaret; Altendahl, Marie; Fellows, Emily; Bliss, Joseph M.; Wheeler, Robert T.; Gale, Cheryl A.

2017-01-01

Candida is a leading cause of late-onset sepsis in premature infants and is thought to invade the host via immature or damaged epithelial barriers. We previously showed that the hyphal form of Candida albicans invades and causes damage to premature intestinal epithelial cells (pIECs), whereas the non-hyphal Candida parapsilosis, also a fungal pathogen of neonates, has less invasion and damage abilities. In this study, we investigated the potential for C. parapsilosis to modulate pathogenic interactions of C. albicans with the premature intestine. While a mixed infection with two fungal pathogens may be expected to result in additive or synergistic damage to pIECs, we instead found that C. parapsilosis was able to protect pIECs from invasion and damage by C. albicans. C. albicans-induced pIEC damage was reduced to a similar extent by multiple different C. parapsilosis strains, but strains differed in their ability to inhibit C. albicans invasion of pIECs, with the inhibitory activity correlating with their adhesiveness for C. albicans and epithelial cells. C. parapsilosis cell-free culture fractions were also able to significantly reduce C. albicans adhesion and damage to pIECs. Furthermore, coadministration of C. parapsilosis cell-free fractions with C. albicans was associated with decreased infection and mortality in zebrafish. These results indicate that C. parapsilosis is able to reduce invasion, damage, and virulence functions of C. albicans. Additionally, the results with cellular and cell-free fractions of yeast cultures suggest that inhibition of pathogenic interactions between C. albicans and host cells by C. parapsilosis occurs via secreted molecules as well as by physical contact with the C. parapsilosis cell surface. We propose that non-invasive commensals can be used to inhibit virulence features of pathogens and deserve further study as a non-pharmacological strategy to protect the fragile epithelial barriers of premature infants. PMID:28382297

Central Role for Dermal Fibroblasts in Skin Model Protection against Candida albicans.

PubMed

Kühbacher, Andreas; Henkel, Helena; Stevens, Philip; Grumaz, Christian; Finkelmeier, Doris; Burger-Kentischer, Anke; Sohn, Kai; Rupp, Steffen

2017-06-01

The fungal pathogen Candida albicans colonizes basically all human epithelial surfaces, including the skin. Under certain conditions, such as immunosuppression, invasion of the epithelia occurs. Not much is known about defense mechanisms against C. albicans in subepithelial layers such as the dermis. Using immune cell-supplemented 3D skin models we defined a new role for fibroblasts in the dermis and identified a minimal set of cell types for skin protection against C. albicans invasion. Dual RNA sequencing of individual host cell populations and C. albicans revealed that dermal invasion is directly impeded by dermal fibroblasts. They are able to integrate signals from the pathogen and CD4+ T cells and shift toward an antimicrobial phenotype with broad specificity that is dependent on Toll-like receptor 2 and interleukin 1β. These results highlight a central function of dermal fibroblasts for skin protection, opening new possibilities for treatment of infectious diseases. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

Synthesis and antimicrobial properties of 3-aryl-1-(1,1'-biphenyl-4-yl)-2-(1H-imidazol-1-yl)propanes as 'carba-analogues' of the N-arylmethyl-N-[(1,1'-biphenyl)-4-ylmethyl])-1H-imidazol-1-amines, a new class of antifungal agents.

PubMed

Castellano, Sabrina; Stefancich, Giorgio; Chillotti, Annalisa; Poni, Graziella

2003-08-01

A new series of 3-phenyl-1-(1,1'-biphenyl-4-yl)-2-(1H-imidazol-1-yl)propane derivatives 2a-l (related to the antifungal bifonazole) was synthesized and tested for antimicrobial activity. A number of substituents on the phenyl ring were chosen to compare the relative biological properties with those of corresponding aza-analogues, previously described by us. The in vitro antifungal activities of the newly synthesized azoles were tested against several pathogenic fungi responsible for human disease. Test pathogens included representatives of yeasts (Candida albicans, Candida parapsilosis, Criptococcus neoformans), dermathophytes (Tricophyton verrucosum, Tricophyton rubrum, Microsporum gypseum) and moulds (Aspergillus fumigatus). Bifonazole and miconazole were used as reference drugs. Title compounds were prepared by alkylation of 1-biphenyl-4-yl-2-imidazol-1-yl-ethanone with the proper arylmethyl halide and subsequent reduction of corresponding ketones applying the Huang-Minlon modification of the Wolff-Kishner reaction.

Enhancement of antidandruff activity of shampoo by biosynthesized silver nanoparticles from Solanum trilobatum plant leaf

NASA Astrophysics Data System (ADS)

Pant, Gaurav; Nayak, Nitesh; Gyana Prasuna, R.

2013-10-01

The present investigation describes simple and effective method for synthesis of silver nanoparticles via green route. Solanum trilobatum Linn extract were prepared by both conventional and homogenization method. We optimized the production of silver nanoparticles under sunlight, microwave and room temperature. The best results were obtained with sunlight irradiation, exhibiting 15-20 nm silver nanoparticles having cubic and hexagonal shape. Biosynthesized nanoparticles were highly toxic to various bacterial strains tested. In this study we report antibacterial activity against various Gram negative ( Klebsiella pneumoniae, Vibrio cholerae and Salmonella typhi) and Gram positive ( Staphylococcus aureus, Bacillus cereus and Micrococcus luteus) bacterial strains. Screening was also performed for any antifungal properties of the nanoparticles against human pathogenic fungal strains ( Candida albicans and Candida parapsilosis). We also demonstrated that these nanoparticles when mixed with shampoo enhance the anti-dandruff effect against dandruff causing fungal pathogens ( Pityrosporum ovale and Pityrosporum folliculitis). The present study showed a simple, rapid and economical route to synthesize silver nanoparticles and their applications hence has a great potential in biomedical field.

Stimulation with lysates of Aspergillus terreus, Candida krusei and Rhizopus oryzae maximizes cross-reactivity of anti-fungal T cells.

PubMed

Deo, Shivashni S; Virassamy, Balaji; Halliday, Catriona; Clancy, Leighton; Chen, Sharon; Meyer, Wieland; Sorrell, Tania C; Gottlieb, David J

2016-01-01

Invasive fungal diseases caused by filamentous fungi and yeasts are significant causes of morbidity and mortality in immunosuppressed hematology patients. We previously published a method to expand Aspergillus fumigatus-specific T cells for clinical cell therapy. In the present study, we investigated expansion of T cells specific for other fungal pathogens and creation of a broadly reactive panfungal T-cell product. Fungal strains selected were those frequently observed in the clinical hematology setting and included Aspergillus, Candida, Fusarium, Rhizopus and Lomentospora/Scedosporium. Four T-cell cultures specific to each fungus were established. We selected lysates of Aspergillus terreus, Candida krusei and Rhizopus oryzae to expand panfungal T cells. Allelic restriction of anti-fungal activity was determined through the use of specific major histocompatibility complex class II-blocking antibodies. Individual T-cell cultures specific to each fungus could be expanded in vitro, generating predominantly CD4(+) T cells of which 8% to 20% were fungus-specific. We successfully expanded panfungal T cells from the peripheral blood (n = 8) and granulocyte-colony-stimulating factor-primed stem cell products (n = 3) of normal donors by using a combination of lysates from Aspergillus terreus, Candida krusei and Rhizopus oryzae. Anti-fungal activity was mediated through human leukocyte antigen (HLA)-DR alleles and was maintained when antigen-presenting cells from partially HLA-DRB1-matched donors were used to stimulate T cells. We demonstrate a method to manufacture panfungal T-cell products with specificity against a range of clinical fungal pathogens by use of the blood and stem cells of healthy donors as the starting material. The safety and efficacy of these products will need to be tested clinically. Copyright © 2015 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Otomastoiditis caused by Candida auris: Case report and literature review.

PubMed

Choi, Hyoung Il; An, Jin; Hwang, Jae Joon; Moon, Soo-Youn; Son, Jun Seong

2017-08-01

Fungal otomastoiditis is a rare disease, but can be fatal for immunocompromised patients. Recently, there have been increasing cases of otologic infection caused by Candida auris. Candida auris can be easily misdiagnosed for other species and treatment is difficult due to multidrug resistance. Clinician should be aware of this rare pathogen, and it should be treated with appropriate antifungal agent with surgical debridement. © 2017 Blackwell Verlag GmbH.

Development and regulation of single- and multi-species Candida albicans biofilms

PubMed Central

Lohse, Matthew B.; Gulati, Megha; Johnson, Alexander D.; Nobile, Clarissa J.

2017-01-01

Candida albicans is among the most prevalent fungal species of the human microbiota and asymptomatically colonizes healthy individuals. However, it is also an opportunistic pathogen that can cause severe, and often fatal, bloodstream infections. The medical impact of C. albicans typically depends on its ability to form biofilms, which are closely packed communities of cells that attach to surfaces, such as tissues and implanted medical devices. In this Review, we provide an overview of the processes involved in the formation of C. albicans biofilms and discuss the core transcriptional network that regulates biofilm development. We also consider some of the advantages that biofilms provide to C. albicans in comparison with planktonic growth and explore polymicrobial biofilms that are formed by C. albicans and certain bacterial species. PMID:29062072

Membership and Behavior of Ultra-Low-Diversity Pathogen Communities Present in the Gut of Humans during Prolonged Critical Illness

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zaborin, Alexander; Smith, Daniel; Garfield, Kevin

We analyzed the 16S rRNA amplicon composition in fecal samples of selected patients during their prolonged stay in an intensive care unit (ICU) and observed the emergence of ultra-low-diversity communities (1 to 4 bacterial taxa) in 30% of the patients. Bacteria associated with the genera Enterococcus and Staphylococcus and the family Enterobacteriaceae comprised the majority of these communities. The composition of cultured species from stool samples correlated to the 16S rRNA analysis and additionally revealed the emergence of Candida albicans and Candida glabrata in ~75% of cases. Four of 14 ICU patients harbored 2-member pathogen communities consisting of one Candidamore » taxon and one bacterial taxon. Bacterial members displayed a high degree of resistance to multiple antibiotics. The virulence potential of the 2-member communities was examined in C. elegans during nutrient deprivation and exposure to opioids in order to mimic local conditions in the gut during critical illness. Under conditions of nutrient deprivation, the bacterial members attenuated the virulence of fungal members, leading to a “commensal lifestyle.” However, exposure to opioids led to a breakdown in this commensalism in 2 of the ultra-low-diversity communities. Application of a novel antivirulence agent (phosphate-polyethylene glycol [Pi-PEG]) that creates local phosphate abundance prevented opioid-induced virulence among these pathogen communities, thus rescuing the commensal lifestyle. To conclude, the gut microflora in critically ill patients can consist of ultra-low-diversity communities of multidrug-resistant pathogenic microbes. Local environmental conditions in gut may direct pathogen communities to adapt to either a commensal style or a pathogenic style.« less

Membership and Behavior of Ultra-Low-Diversity Pathogen Communities Present in the Gut of Humans during Prolonged Critical Illness

DOE PAGES

Zaborin, Alexander; Smith, Daniel; Garfield, Kevin; ...

2014-09-23

We analyzed the 16S rRNA amplicon composition in fecal samples of selected patients during their prolonged stay in an intensive care unit (ICU) and observed the emergence of ultra-low-diversity communities (1 to 4 bacterial taxa) in 30% of the patients. Bacteria associated with the genera Enterococcus and Staphylococcus and the family Enterobacteriaceae comprised the majority of these communities. The composition of cultured species from stool samples correlated to the 16S rRNA analysis and additionally revealed the emergence of Candida albicans and Candida glabrata in ~75% of cases. Four of 14 ICU patients harbored 2-member pathogen communities consisting of one Candidamore » taxon and one bacterial taxon. Bacterial members displayed a high degree of resistance to multiple antibiotics. The virulence potential of the 2-member communities was examined in C. elegans during nutrient deprivation and exposure to opioids in order to mimic local conditions in the gut during critical illness. Under conditions of nutrient deprivation, the bacterial members attenuated the virulence of fungal members, leading to a “commensal lifestyle.” However, exposure to opioids led to a breakdown in this commensalism in 2 of the ultra-low-diversity communities. Application of a novel antivirulence agent (phosphate-polyethylene glycol [Pi-PEG]) that creates local phosphate abundance prevented opioid-induced virulence among these pathogen communities, thus rescuing the commensal lifestyle. To conclude, the gut microflora in critically ill patients can consist of ultra-low-diversity communities of multidrug-resistant pathogenic microbes. Local environmental conditions in gut may direct pathogen communities to adapt to either a commensal style or a pathogenic style.« less

IL-27 Induced by Select Candida spp. via TLR7/NOD2 Signaling and IFN-β Production Inhibits Fungal Clearance

PubMed Central

Patin, Emmanuel C.; Jones, Adam V.; Thompson, Aiysha; Clement, Mathew; Liao, Chia-Te; Griffiths, James S.; Wallace, Leah E.; Bryant, Clare E.; Lang, Roland; Rosenstiel, Philip; Humphreys, Ian R.; Taylor, Philip R.

2016-01-01

Candida spp. elicit cytokine production downstream of various pathogen recognition receptors, including C-type lectin-like receptors, TLRs, and nucleotide oligomerization domain (NOD)–like receptors. IL-12 family members IL-12p70 and IL-23 are important for host immunity against Candida spp. In this article, we show that IL-27, another IL-12 family member, is produced by myeloid cells in response to selected Candida spp. We demonstrate a novel mechanism for Candida parapsilosis–mediated induction of IL-27 in a TLR7-, MyD88-, and NOD2-dependent manner. Our data revealed that IFN-β is induced by C. parapsilosis, which in turn signals through the IFN-α/β receptor and STAT1/2 to induce IL-27. Moreover, IL-27R (WSX-1)–deficient mice systemically infected with C. parapsilosis displayed enhanced pathogen clearance compared with wild-type mice. This was associated with increased levels of proinflammatory cytokines in the serum and increased IFN-γ and IL-17 responses in the spleens of IL-27R–deficient mice. Thus, our data define a novel link between C. parapsilosis, TLR7, NOD2, IFN-β, and IL-27, and we have identified an important role for IL-27 in the immune response against C. parapsilosis. Overall, these findings demonstrate an important mechanism for the suppression of protective immune responses during infection with C. parapsilosis, which has potential relevance for infections with other fungal pathogens. PMID:27259855

Aspartic protease inhibitors as potential anti-Candida albicans drugs: impacts on fungal biology, virulence and pathogenesis.

PubMed

Braga-Silva, L A; Santos, A L S

2011-01-01

Mycoses are still one of the most problematic illnesses worldwide, especially affecting immunocompromised individuals. The development of novel antifungal drugs is becoming more demanding every day, since existing drugs either have too many side effects or they tend to lose effectiveness due to the resistant fungal strains. In this scenario, Candida albicans is still the main fungal pathogen isolated in hospitals. Pathogenicity results essentially from modifications of the host defense mechanisms that secondarily initiate transformations in the fungal behavior. The pathogenesis of C. albicans is multifactorial and different virulence attributes are important during the various stages of infection. Some virulence factors, like the secreted aspartic proteases (Saps), play a role in several infection stages and the inhibition of one of the many stages may contribute to the containment of the pathogen and thus should help in the treatment of disease. Therefore, Saps are potential targets for the development of novel anti-C. albicans drugs. Herein, we review the beneficial properties of pepstatin A and aspartic-type protease inhibitors used in the anti-human immunodeficiency virus chemotherapy on C. albicans, with particular emphasis in the effects on Sap activity, proliferation, morphogenesis (yeasts into mycelia transformation), ultrastructural architecture, adhesion to mammalian cells and abiotic materials, modulation of unrelated virulence factors (e.g., surface glycoconjugates, lipases and sterol), experimental candidiasis infection as well as synergistic properties when conjugated with classical antifungals. Collectively, these positive findings have stimulated the search for novel natural and/or synthetic pharmacological compounds with anti-aspartic protease properties against the human opportunistic fungus C. albicans.

Small but Crucial: The Novel Small Heat Shock Protein Hsp21 Mediates Stress Adaptation and Virulence in Candida albicans

PubMed Central

Mayer, François L.; Wilson, Duncan; Jacobsen, Ilse D.; Miramón, Pedro; Slesiona, Silvia; Bohovych, Iryna M.; Brown, Alistair J. P.; Hube, Bernhard

2012-01-01

Small heat shock proteins (sHsps) have multiple cellular functions. However, the biological function of sHsps in pathogenic microorganisms is largely unknown. In the present study we identified and characterized the novel sHsp Hsp21 of the human fungal pathogen Candida albicans. Using a reverse genetics approach we demonstrate the importance of Hsp21 for resistance of C. albicans to specific stresses, including thermal and oxidative stress. Furthermore, a hsp21Δ/Δ mutant was defective in invasive growth and formed significantly shorter filaments compared to the wild type under various filament-inducing conditions. Although adhesion to and invasion into human-derived endothelial and oral epithelial cells was unaltered, the hsp21Δ/Δ mutant exhibited a strongly reduced capacity to damage both cell lines. Furthermore, Hsp21 was required for resisting killing by human neutrophils. Measurements of intracellular levels of stress protective molecules demonstrated that Hsp21 is involved in both glycerol and glycogen regulation and plays a major role in trehalose homeostasis in response to elevated temperatures. Mutants defective in trehalose and, to a lesser extent, glycerol synthesis phenocopied HSP21 deletion in terms of increased susceptibility to environmental stress, strongly impaired capacity to damage epithelial cells and increased sensitivity to the killing activities of human primary neutrophils. Via systematic analysis of the three main C. albicans stress-responsive kinases (Mkc1, Cek1, Hog1) under a range of stressors, we demonstrate Hsp21-dependent phosphorylation of Cek1 in response to elevated temperatures. Finally, the hsp21Δ/Δ mutant displayed strongly attenuated virulence in two in vivo infection models. Taken together, Hsp21 mediates adaptation to specific stresses via fine-tuning homeostasis of compatible solutes and activation of the Cek1 pathway, and is crucial for multiple stages of C. albicans pathogenicity. Hsp21 therefore represents the first reported example of a small heat shock protein functioning as a virulence factor in a eukaryotic pathogen. PMID:22685587

The antibiotic polymyxin B exhibits novel antifungal activity against Fusarium species.

PubMed

Hsu, Li-Hang; Wang, Hsuan-Fu; Sun, Pei-Lun; Hu, Fung-Rong; Chen, Ying-Lien

2017-06-01

The genus Fusarium comprises many species, including Fusarium oxysporum, Fusarium solani, Fusarium graminearum and Fusarium verticillioides, and causes severe infections in plants and humans. In clinical settings, Fusarium is the third most frequent mould to cause invasive fungal infections after Aspergillus and the Mucorales. F. solani and F. oxysporum are the most prevalent Fusarium spp. causing clinical disease. However, few effective antifungal drugs are available to treat human and plant Fusarium infections. The cationic peptide antibiotic polymyxin B (PMB) exhibits antifungal activity against the human fungal pathogens Candida albicans and Cryptococcus neoformans, but its efficacy against Fusarium spp. is unknown. In this study, the antifungal activity of PMB was tested against 12 Fusarium strains that infect humans and plants (banana, tomato, melon, pea, wheat and maize). PMB was fungicidal against all 12 Fusarium strains, with minimum fungicidal concentrations of 32 µg/mL or 64 µg/mL for most strains tested, as evidenced by broth dilution, methylene blue staining and XTT reduction assays. PMB can reduce the germination rates of conidia, but not chlamydospores, and can cause defects in cell membrane integrity in Fusarium strains. PMB exhibits synergistic activity with posaconazole and can potentiate the effect of fluconazole, voriconazole or amphotericin B against Fusarium spp. However, PMB does not show synergistic effects with fluconazole against Fusarium spp. as it does against Candida glabrata and C. neoformans, indicating evolutionary divergence of mechanisms between yeast pathogens and the filamentous fungus Fusarium. Copyright © 2017 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

Selected Essential Oils as Antifungal Agents Against Antibiotic-Resistant Candida spp.: In Vitro Study on Clinical and Food-Borne Isolates.

PubMed

Rajkowska, Katarzyna; Kunicka-Styczyńska, Alina; Maroszyńska, Marta

2017-01-01

Candida spp. cause significant health problems, inducing various types of superficial and deep-seated mycoses in humans. As a result of the increasing antibiotic resistance among pathogenic yeasts, the interest in alternative agents of antifungal activity is growing. This study evaluated the antimicrobial activity of selected essential oils (EOs) against Candida clinical and food-borne strains, including antibiotic-resistant isolates, in relation to yeast cell surface hydrophobicity (CSH). Candida strains showed different range of susceptibility to tea tree, thyme, peppermint, and clove oils, and peppermint oil demonstrated the lowest anticandidal activity with minimal inhibitory concentrations (MICs) of 0.03-8.0% v/v. MIC values for thyme and clove oils ranged from 0.03% to 0.25% v/v, and for tea tree oil-from 0.12% to 2.0% v/v. The exception was Candida tropicalis food-borne strain, the growth of which was inhibited after application of EOs at concentration of 8% v/v. Due to diverse yeast susceptibility to EOs, isolates were divided into five clusters in a principal component analysis model, each containing both clinical and food-borne strains. Hydrophobic properties of yeast were also diversified, and 37% of clinical and 50% of food-borne strains exhibited high hydrophobicity. The study indicates high homology of clinical and food-borne Candida isolates in relation to their susceptibility to anticandidal agents and hydrophobic properties. The susceptibility of yeasts to EOs could be partially related to their CSH. High antifungal activity of examined EOs, also against antibiotic-resistant isolates, indicates their usefulness as agents preventing the development of Candida strains of different origin.

Comparative Study of Esterase and Hemolytic Activities in Clinically Important Candida Species, Isolated From Oral Cavity of Diabetic and Non-diabetic Individuals.

PubMed

Fatahinia, Mahnaz; Poormohamadi, Farzad; Zarei Mahmoudabadi, Ali

2015-03-01

Diabetes mellitus as a chronic metabolic disease occurs in patients with partial or complete deficiency of insulin secretion or disorder in action of insulin on tissue. The disease is known to provide conditions for overgrowth of Candida species. Candida spp. cause candidiasis by many virulence factors such as esterase, hemolysin and phospholipase. This study aimed to compare esterase and hemolytic activity in various Candida species isolated from oral cavity of diabetic and non-diabetic individuals. Swab samples were taken from 95 patients with diabetes (35 men and 60 women) and 95 normal persons (42 men and 53 women) and cultured on Sabouraud dextrose agar. Identification of isolated yeasts was performed by germ tube test, morphology on CHROMagar Candida medium, corn meal agar and ability to grow at 45°C. Hemolysin activity was evaluated using blood plate assay and esterase activity was determined using the Tween 80 opacity test. Different Candida species were isolated from 57 (60%) diabetic and 24 (25%) non-diabetic individuals. Esterase activity was detected in all Candida isolates. Only 21.6% of C. albicans from patients with diabetes had esterase activity as + 3, while it ranged from + 1 to + 2 in others. Hemolytic activity was determined in C. albicans, C. dubliniensis, C. glabrata and C. krusei as 0.79, 0.58, 0.66 and 0.74, respectively. Hemolytic activity was significantly different in the two groups of diabetics and non-diabetics. Oral carriage of C. albicans in the diabetic group (n = 42; 66.7%) was significantly greater than the control group (n = 16; 57.1%). Esterase activity of C. albicans in diabetic group was higher than non-diabetic group. Although C. albicans remains the most frequently pathogenic yeast for human, but other species are increasing.

Antimicrobial activity and cytotoxic effects of Magnolia dealbata and its active compounds.

PubMed

Jacobo-Salcedo, Maria del Rosario; Gonzalez-Espindola, Luis Angel; Alonso-Castro, Angel Josabad; Gonzalez-Martinez, Marisela del Rocio; Domínguez, Fabiola; Garcia-Carranca, Alejandro

2011-08-01

Multi-drug resistance is of great concern for public health worldwide and necessitates the search for new antimicrobials from sources such as plants. Several Magnolia (Magnoliaceae) species have been reported to exert antimicrobial effects on sensitive and multidrug-resistant microorganisms. However, the antimicrobial properties of Magnolia dealbata have not been experimentally evaluated. The antimicrobial effects of an ethanol extract of Magnolia dealbata seeds (MDE) and its active compounds honokiol (HK) and magnolol (MG) were tested against the phytopathogen Clavibacter michiganensis subsp. michiganensis and several human multi-drug resistant pathogens using the disk-diffusion assay. The effects of MDE and its active compounds on the viability of human peripheral blood mononuclear cells (PBMC) were evaluated using MTT assay. MDE and its active compounds had antimicrobial activity (inhibition zone > 10 mm) against C. michiganensis, Pseudomonas aeruginosa, Acinetobacter baumannii, Acinetobacter lwoffii, Candida albicans, Candida tropicalis and Trichosporon belgeii. The results suggest that M. dealbata and its active compounds have selective antimicrobial effects against drug-resistant fungal and Gram (-) bacteria and exert minimal toxic effects on human PMBC.

Candida albicans and C. tropicalis Isolates from the Expired Breathes of Captive Dolphins and Their Environments in an Aquarium

PubMed Central

Takahashi, Hideo; Ueda, Keiichi; Itano, Eiko Nakagawa; Yanagisawa, Makio; Murata, Yoshiteru; Murata, Michiko; Yaguchi, Takashi; Murakami, Masaru; Kamei, Katsuhiko; Inomata, Tomo; Miyahara, Hirokazu; Sano, Ayako; Uchida, Senzo

2010-01-01

Genotypes of Candida spp. isolated from exhalation of 20 dolphins, 11 water samples from captive pools, and 24 oral cavities of staff members in an aquarium using a combination of multiple drug resistance 1 gene (MDR1) and the internal transcribed spacer (ITS) 1 5.8s-ITS 2 regions of ribosomal RNA gene (ITS rDNA) sequences were studied. The holding ratios of the dolphins, captive pools, and staff members were 70, 90, and 29%, respectively. Isolated pathogenic yeast species common to the dolphins and environments were Candida albicans and C. tropicalis. Identical genotypes in both Candida spp. based on the combination of MDR1 and ITSrDNA were found in some dolphins, between a dolphin and a staff, among dolphins and environments, and among environments. The results indicated the diffusion and exchange of pathogenic yeasts at the aquarium among dolphins and environments. The isolates at the aquarium showed higher rates of resistance to azole antifungals compared to reference isolates. PMID:21234394

Potential Antifungal Targets against a Candida Biofilm Based on an Enzyme in the Arachidonic Acid Cascade—A Review

PubMed Central

Liu, Xinning; Wang, Decai; Yu, Cuixiang; Li, Tao; Liu, Jianqiao; Sun, Shujuan

2016-01-01

Candida is an important opportunistic fungal pathogen, especially in biofilm associated infections. The formation of a Candida biofilm can decrease Candida sensitivity to antifungal drugs and cause drug resistance. Although many effective antifungal drugs are available, their applications are limited due to their high toxicity and cost. Seeking new antifungal agents that are effective against biofilm-associated infection is an urgent need. Many research efforts are underway, and some progress has been made in this field. It has been shown that the arachidonic acid cascade plays an important role in fungal morphogenesis and pathogenicity. Notably, prostaglandin E2 (PGE2) can promote the formation of a Candida biofilm. Recently, the inhibition of PGE2 has received much attention. Studies have shown that cyclooxygenase (COX) inhibitors, such as aspirin, ibuprofen, and indomethacin, combined with fluconazole can significantly reduce Candida adhesion and biofilm development and increase fluconazole susceptibility; the MIC of fluconazole can be decrease from 64 to 2 μg/ml when used in combination with ibuprofen. In addition, in vivo studies have also confirmed the antifungal activities of these inhibitors. In this article, we mainly review the relationship between PGE2 and Candida biofilm, summarize the antifungal activities of COX inhibitors and analyze the possible antifungal activity of microsomal prostaglandin E synthase-1 (MPGES-1) inhibitors; additionally, other factors that influence PGE2 production are also discussed. Hopefully this review can disclose potential antifungal targets based on the arachidonic acid cascade and provide a prevailing strategy to alleviate Candida albicans biofilm formation. PMID:27999568

The vaginal mycobiome: A contemporary perspective on fungi in women's health and diseases.

PubMed

Bradford, L Latéy; Ravel, Jacques

2017-04-03

Most of what is known about fungi in the human vagina has come from culture-based studies and phenotypic characterization of single organisms. Though valuable, these approaches have masked the complexity of fungal communities within the vagina. The vaginal mycobiome has become an emerging field of study as genomics tools are increasingly employed and we begin to appreciate the role these fungal communities play in human health and disease. Though vastly outnumbered by its bacterial counterparts, fungi are important constituents of the vaginal ecosystem in many healthy women. Candida albicans, an opportunistic fungal pathogen, colonizes 20% of women without causing any overt symptoms, yet it is one of the leading causes of infectious vaginitis. Understanding its mechanisms of commensalism and patho-genesis are both essential to developing more effective therapies. Describing the interactions between Candida, bacteria (such as Lactobacillus spp.) and other fungi in the vagina is funda-mental to our characterization of the vaginal mycobiome.

Candida innate immunity at the mucosa.

PubMed

Richardson, Jonathan P; Moyes, David L; Ho, Jemima; Naglik, Julian R

2018-03-09

The tremendous diversity in microbial species that colonise the mucosal surfaces of the human body is only now beginning to be fully appreciated. Distinguishing between the behaviour of commensal microbes and harmful pathogens that reside at mucosal sites in the body is a complex, and exquisitely fine-tuned process central to mucosal health. The fungal pathobiont Candida albicans is frequently isolated from mucosal surfaces with an asymptomatic carriage rate of approximately 60% in the human population. While normally a benign member of the microbiota, overgrowth of C. albicans often results in localised mucosal infection causing morbidity in otherwise healthy individuals, and invasive infection that often causes death in the absence of effective immune defence. C. albicans triggers numerous innate immune responses at mucosal surfaces, and detection of C. albicans hyphae in particular, stimulates the production of antimicrobial peptides, danger-associated molecular patterns and cytokines that function to reduce fungal burdens during infection. This review will summarise our current understanding of innate immune responses to C. albicans at mucosal surfaces. Copyright © 2018. Published by Elsevier Ltd.

The vaginal mycobiome: A contemporary perspective on fungi in women's health and diseases

PubMed Central

2017-01-01

ABSTRACT Most of what is known about fungi in the human vagina has come from culture-based studies and phenotypic characterization of single organisms. Though valuable, these approaches have masked the complexity of fungal communities within the vagina. The vaginal mycobiome has become an emerging field of study as genomics tools are increasingly employed and we begin to appreciate the role these fungal communities play in human health and disease. Though vastly outnumbered by its bacterial counterparts, fungi are important constituents of the vaginal ecosystem in many healthy women. Candida albicans, an opportunistic fungal pathogen, colonizes 20% of women without causing any overt symptoms, yet it is one of the leading causes of infectious vaginitis. Understanding its mechanisms of commensalism and patho-genesis are both essential to developing more effective therapies. Describing the interactions between Candida, bacteria (such as Lactobacillus spp.) and other fungi in the vagina is funda-mental to our characterization of the vaginal mycobiome. PMID:27657355

A Virtual Infection Model Quantifies Innate Effector Mechanisms and Candida albicans Immune Escape in Human Blood

PubMed Central

Bieber, Kristin; Martin, Ronny; Figge, Marc Thilo; Kurzai, Oliver

2014-01-01

Candida albicans bloodstream infection is increasingly frequent and can result in disseminated candidiasis associated with high mortality rates. To analyze the innate immune response against C. albicans, fungal cells were added to human whole-blood samples. After inoculation, C. albicans started to filament and predominantly associate with neutrophils, whereas only a minority of fungal cells became attached to monocytes. While many parameters of host-pathogen interaction were accessible to direct experimental quantification in the whole-blood infection assay, others were not. To overcome these limitations, we generated a virtual infection model that allowed detailed and quantitative predictions on the dynamics of host-pathogen interaction. Experimental time-resolved data were simulated using a state-based modeling approach combined with the Monte Carlo method of simulated annealing to obtain quantitative predictions on a priori unknown transition rates and to identify the main axis of antifungal immunity. Results clearly demonstrated a predominant role of neutrophils, mediated by phagocytosis and intracellular killing as well as the release of antifungal effector molecules upon activation, resulting in extracellular fungicidal activity. Both mechanisms together account for almost of C. albicans killing, clearly proving that beside being present in larger numbers than other leukocytes, neutrophils functionally dominate the immune response against C. albicans in human blood. A fraction of C. albicans cells escaped phagocytosis and remained extracellular and viable for up to four hours. This immune escape was independent of filamentation and fungal activity and not linked to exhaustion or inactivation of innate immune cells. The occurrence of C. albicans cells being resistant against phagocytosis may account for the high proportion of dissemination in C. albicans bloodstream infection. Taken together, iterative experiment–model–experiment cycles allowed quantitative analyses of the interplay between host and pathogen in a complex environment like human blood. PMID:24586131

A virtual infection model quantifies innate effector mechanisms and Candida albicans immune escape in human blood.

PubMed

Hünniger, Kerstin; Lehnert, Teresa; Bieber, Kristin; Martin, Ronny; Figge, Marc Thilo; Kurzai, Oliver

2014-02-01

Candida albicans bloodstream infection is increasingly frequent and can result in disseminated candidiasis associated with high mortality rates. To analyze the innate immune response against C. albicans, fungal cells were added to human whole-blood samples. After inoculation, C. albicans started to filament and predominantly associate with neutrophils, whereas only a minority of fungal cells became attached to monocytes. While many parameters of host-pathogen interaction were accessible to direct experimental quantification in the whole-blood infection assay, others were not. To overcome these limitations, we generated a virtual infection model that allowed detailed and quantitative predictions on the dynamics of host-pathogen interaction. Experimental time-resolved data were simulated using a state-based modeling approach combined with the Monte Carlo method of simulated annealing to obtain quantitative predictions on a priori unknown transition rates and to identify the main axis of antifungal immunity. Results clearly demonstrated a predominant role of neutrophils, mediated by phagocytosis and intracellular killing as well as the release of antifungal effector molecules upon activation, resulting in extracellular fungicidal activity. Both mechanisms together account for almost [Formula: see text] of C. albicans killing, clearly proving that beside being present in larger numbers than other leukocytes, neutrophils functionally dominate the immune response against C. albicans in human blood. A fraction of C. albicans cells escaped phagocytosis and remained extracellular and viable for up to four hours. This immune escape was independent of filamentation and fungal activity and not linked to exhaustion or inactivation of innate immune cells. The occurrence of C. albicans cells being resistant against phagocytosis may account for the high proportion of dissemination in C. albicans bloodstream infection. Taken together, iterative experiment-model-experiment cycles allowed quantitative analyses of the interplay between host and pathogen in a complex environment like human blood.

Ultraviolet Microscopy of Candida albicans

PubMed Central

Balish, Edward; Svihla, George

1966-01-01

Balish, Edward (Argonne National Laboratory, Argonne, Ill.), and George Svihla. Ultraviolet microscopy of Candida albicans. J. Bacteriol. 92:1812–1820. 1966.—Yeast and mycelial strains of Candida albicans were grown in medium supplemented with sulfur amino acids in an effort to determine factors that control the morphology and pathogenicity of the organism. Ultraviolet microscopy revealed a greater concentration of S-adenosylmethionine in the vacuoles of the mycelial phase than in those of yeast phases. Supplementation with amino acids greatly increased the concentration of S-adenosylmethionine in the mycelial phase, and made these cells more sensitive to the lytic action of snail gut enzymes than two yeast phase strains. This indicates a difference in cell wall structure that may be related to the pathogenicity of the mycelial phase. Images PMID:5958110

Introducing fluorescence resonance energy transfer-based biosensors for the analysis of cAMP-PKA signalling in the fungal pathogen Candida glabrata.

PubMed

Demuyser, Liesbeth; Van Genechten, Wouter; Mizuno, Hideaki; Colombo, Sonia; Van Dijck, Patrick

2018-05-29

The cyclic adenosine monophosphate-protein kinase A (cAMP-PKA) pathway is central to signal transduction in many organisms. In pathogenic fungi such as Candida albicans, this signalling cascade has proven to be involved in several processes, such as virulence, indicating its potential importance in antifungal drug discovery. Candida glabrata is an upcoming pathogen of the same species, yet information regarding the role of cAMP-PKA signalling in virulence is largely lacking. To enable efficient monitoring of cAMP-PKA activity in this pathogen, we here present the usage of two FRET-based biosensors. Both variations in the activity of PKA and the quantity of cAMP can be detected in a time-resolved manner, as we exemplify by glucose-induced activation of the pathway. We also present information on how to adequately process and analyse the data in a mathematically correct and physiologically relevant manner. These sensors will be of great benefit for scientists interested in linking the cAMP-PKA signalling cascade to downstream processes, such as virulence, possibly in a host environment. © 2018 John Wiley & Sons Ltd.

Plants’ Natural Products as Alternative Promising Anti-Candida Drugs

PubMed Central

Soliman, Sameh; Alnajdy, Dina; El-Keblawy, Ali A.; Mosa, Kareem A.; Khoder, Ghalia; Noreddin, Ayman M.

2017-01-01

Candida is a serious life-threatening pathogen, particularly with immunocompromised patients. Candida infections are considered as a major cause of morbidity and mortality in a broad range of immunocompromised patients. Candida infections are common in hospitalized patients and elderly people. The difficulty to eradicate Candida infections is owing to its unique switch between yeast and hyphae forms and more likely to biofilm formations that render resistance to antifungal therapy. Plants are known sources of natural medicines. Several plants show significant anti-Candida activities and some of them have lower minimum inhibitory concentration, making them promising candidates for anti-Candida therapy. However, none of these plant products is marketed for anti-Candida therapy because of lack of sufficient information about their efficacy, toxicity, and kinetics. This review revises major plants that have been tested for anti-Candida activities with recommendations for further use of some of these plants for more investigation and in vivo testing including the use of nanostructure lipid system. PMID:28989245

Immunohistopathology of Prototheca wickerhamii in cutaneous lesions of protothecosis.

PubMed

Kano, Rui; Sobukawa, Hideto; Suzuki, Minako; Hiruma, Masataro; Shibuya, Kazutoshi; Hasegawa, Atsuhiko; Kamata, Hiroshi

2014-01-01

Protothecosis is a rare infection caused by pathogenic algae of the genus Prototheca. Prototheca wickerhamii causes cutaneous/subcutaneous opportunistic infections in humans and small animals. The diagnosis of protothecosis is based on histopathological examination of this organism, which can be confused with other fungi and inflammatory cells in infected tissues. In this study, immunohistopathological investigation was made of infected cutaneous human and animal tissues exhibiting protothecosis using rabbit antiserum against P. wickerhamii. Serum detected P. wickerhamii in human and feline protothecosis tissues, and did not react with Candida albicans in the human kidney tissues showing candidiasis. This antiserum can therefore differentiate P. wickerhamii cells from the yeast-like cells of C. albicans and Prototheca zopfii in target tissues.

Gaining Insights from Candida Biofilm Heterogeneity: One Size Does Not Fit All

PubMed Central

Kean, Ryan; Delaney, Christopher; Rajendran, Ranjith; Sherry, Leighann; Metcalfe, Rebecca; Thomas, Rachael; McLean, William; Williams, Craig; Ramage, Gordon

2018-01-01

Despite their clinical significance and substantial human health burden, fungal infections remain relatively under-appreciated. The widespread overuse of antibiotics and the increasing requirement for indwelling medical devices provides an opportunistic potential for the overgrowth and colonization of pathogenic Candida species on both biological and inert substrates. Indeed, it is now widely recognized that biofilms are a highly important part of their virulence repertoire. Candida albicans is regarded as the primary fungal biofilm forming species, yet there is also increasing interest and growing body of evidence for non-Candida albicans species (NCAS) biofilms, and interkingdom biofilm interactions. C. albicans biofilms are heterogeneous structures by definition, existing as three-dimensional populations of yeast, pseudo-hyphae, and hyphae, embedded within a self-produced extracellular matrix. Classical molecular approaches, driven by extensive studies of laboratory strains and mutants, have enhanced our knowledge and understanding of how these complex communities develop, thrive, and cause host-mediated damage. Yet our clinical observations tell a different story, with differential patient responses potentially due to inherent biological heterogeneity from specific clinical isolates associated with their infections. This review explores some of the recent advances made in an attempt to explore the importance of working with clinical isolates, and what this has taught us. PMID:29371505

The MAP kinase-activated protein kinase Rck2p regulates cellular responses to cell wall stresses, filamentation and virulence in the human fungal pathogen Candida albicans.

PubMed

Li, Xichuan; Du, Wei; Zhao, Jingwen; Zhang, Lilin; Zhu, Zhiyan; Jiang, Linghuo

2010-06-01

Rck2p is the Hog1p-MAP kinase-activated protein kinase required for the attenuation of protein synthesis in response to an osmotic challenge in Saccharomyces cerevisiae. Rck2p also regulates rapamycin sensitivity in both S. cerevisiae and Candida albicans. In this study, we demonstrate that the deletion of CaRCK2 renders C. albicans cells sensitive to, and CaRck2p translocates from the cytosol to the nucleus in response to, cell wall stresses caused by Congo red, Calcoflor White, elevated heat and zymolyase. However, the kinase activity of CaRck2p is not required for the cellular response to these cell wall stresses. Furthermore, transcripts of cell wall protein-encoding genes CaBGL2, CaHWP1 and CaXOG1 are reduced in C. albicans cells lacking CaRCK2. The deletion of CaRCK2 also reduces the in vitro filamentation of C. albicans and its virulence in a mouse model of systemic candidasis. The kinase activity of CaRck2p is required for the virulence, but not for the in vitro filamentation, in C. albicans. Therefore, Rck2p regulates cellular responses to cell wall stresses, filamentation and virulence in the human fungal pathogen C. albicans.

The Role of IL-17 in Protection against Mucosal Candida Infections

PubMed Central

Mengesha, Bemnet G.; Conti, Heather R.

2017-01-01

Interleukin-17 (IL-17) is a proinflammatory cytokine produced by adaptive CD4+ T helper cells and innate lymphocytes, such as γδ-T cells and TCRβ+ “natural” Th17 cells. IL-17 activates signaling through the IL-17 receptor, which induces other proinflammatory cytokines, antimicrobial peptides and neutrophil chemokines that are important for antifungal activity. The importance of IL-17 in protective antifungal immunity is evident in mice and humans, where various genetic defects related to the IL-17-signaling pathway render them highly susceptible to forms of candidiasis such oropharyngeal candidiasis (OPC) or more broadly chronic mucocutaneous candidiasis (CMC), both caused mainly by the opportunistic fungal pathogen Candida albicans. OPC is common in infants and the elderly, HIV/AIDS and patients receiving chemotherapy and/or radiotherapy for head and neck cancers. This review focuses on the role of IL-17 in protection against candidiasis, and includes a brief discussion of non-Candida albicans fungal infections, as well as how therapeutic interventions blocking IL-17-related components can affect antifungal immunity. PMID:29371568

Identification of fungi in shotgun metagenomics datasets

PubMed Central

Donovan, Paul D.; Gonzalez, Gabriel; Higgins, Desmond G.

2018-01-01

Metagenomics uses nucleic acid sequencing to characterize species diversity in different niches such as environmental biomes or the human microbiome. Most studies have used 16S rRNA amplicon sequencing to identify bacteria. However, the decreasing cost of sequencing has resulted in a gradual shift away from amplicon analyses and towards shotgun metagenomic sequencing. Shotgun metagenomic data can be used to identify a wide range of species, but have rarely been applied to fungal identification. Here, we develop a sequence classification pipeline, FindFungi, and use it to identify fungal sequences in public metagenome datasets. We focus primarily on animal metagenomes, especially those from pig and mouse microbiomes. We identified fungi in 39 of 70 datasets comprising 71 fungal species. At least 11 pathogenic species with zoonotic potential were identified, including Candida tropicalis. We identified Pseudogymnoascus species from 13 Antarctic soil samples initially analyzed for the presence of bacteria capable of degrading diesel oil. We also show that Candida tropicalis and Candida loboi are likely the same species. In addition, we identify several examples where contaminating DNA was erroneously included in fungal genome assemblies. PMID:29444186

Yeast microbiota of natural cavities of manatees (Trichechus inunguis and Trichechus manatus) in Brazil and its relevance for animal health and management in captivity.

PubMed

Sidrim, José Júlio Costa; Carvalho, Vitor Luz; Castelo-Branco, Débora de Souza Collares Maia; Brilhante, Raimunda Sâmia Nogueira; Bandeira, Tereza de Jesus Pinheiro Gomes; Cordeiro, Rossana de Aguiar; Guedes, Gláucia Morgana de Melo; Barbosa, Giovanna Riello; Lazzarini, Stella Maris; Oliveira, Daniella Carvalho Ribeiro; de Meirelles, Ana Carolina Oliveira; Attademo, Fernanda Löffler Niemeyer; Freire, Augusto Carlos da Bôaviagem; Moreira, José Luciano Bezerra; Monteiro, André Jalles; Rocha, Marcos Fábio Gadelha

2015-10-01

The aim of this study was to characterize the yeast microbiota of natural cavities of manatees kept in captivity in Brazil. Sterile swabs from the oral cavity, nostrils, genital opening, and rectum of 50 Trichechus inunguis and 26 Trichechus manatus were collected. The samples were plated on Sabouraud agar with chloramphenicol and incubated at 25 °C for 5 days. The yeasts isolated were phenotypically identified by biochemical and micromorphological tests. Overall, 141 strains were isolated, of which 112 were from T. inunguis (Candida albicans, Candida parapsilosis sensu stricto, Candida orthopsilosis, Candida metapsilosis, Candida guilliermondii, Candida pelliculosa, Candida tropicalis, Candida glabrata, Candida famata, Candida krusei, Candida norvegensis, Candida ciferri, Trichosporon sp., Rhodotorula sp., Cryptococcus laurentii) and 29 were from T. manatus (C. albicans, C. tropicalis, C. famata, C. guilliermondii, C. krusei, Rhodotorula sp., Rhodotorula mucilaginosa, Rhodotorula minuta, Trichosporon sp.). This was the first systematic study to investigate the importance of yeasts as components of the microbiota of sirenians, demonstrating the presence of potentially pathogenic species, which highlights the importance of maintaining adequate artificial conditions for the health of captive manatees.

Candidemia in the intensive care unit: A 12-year retrospective cohort study in Reunion Island.

PubMed

Hoarau, G; Picot, S; Lemant, J; Peytral, J; Poubeau, P; Zunic, P; Mohr, C; Coueffe, X; Gerardin, P; Antok, E

2018-05-09

We aimed to describe the epidemiology of Candida bloodstream infection in an intensive care unit (ICU) in Reunion Island. We performed a retrospective cohort study and evaluated 63 candidemia episodes, which occurred between January 2004 and December 2015 in the ICU of a University Hospital in St-Pierre. The incidence rate of candidemia in the ICU was estimated at 7.6%. Candida albicans was the most common yeast pathogen species recovered (54%), followed by Candida glabrata (17%), Candida tropicalis (12%) and Candida parapsilosis (10%). Between 2012 and 2015, we also observed a modification of antifungal use. The epidemiology of candidemia in Reunion Island is characterized by the predominance of Candida albicans and by the relative importance of Candida tropicalis. This pattern corresponds to a model of epidemiological transition between the one usually observed in tropical areas and the one observed in temperate countries. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

[Enzymatic activity, slime production and antifungal agent sensitivity of Candida sp].

PubMed

Silva, Jaqueline Otero; Ferreira, Joseane Cristina; Candido, Regina Célia

2007-01-01

Abilith of Candida spp to secrete extracellular enzymes and slime has been associated as pathogenicity factors. Out of a total of 37 strains of Candida sp, 100% were proteinase producers, 83.8% were phospholipase producers, 64.9% were slime producers and 100% were sensitive to fluconazole and itraconazole. Seventeen typings (enzymes/slime) were found. This methodology presented a good discrimination rate (D=0.93) and could be used for phenotypic characterization of yeasts.

Usefulness of the Non-conventional Caenorhabditis elegans Model to Assess Candida Virulence.

PubMed

Ortega-Riveros, Marcelo; De-la-Pinta, Iker; Marcos-Arias, Cristina; Ezpeleta, Guillermo; Quindós, Guillermo; Eraso, Elena

2017-10-01

Invasive candidiasis is caused mainly by Candida albicans, but other Candida species have increasing etiologies. These species show different virulence and susceptibility levels to antifungal drugs. The aims of this study were to evaluate the usefulness of the non-conventional model Caenorhabditis elegans to assess the in vivo virulence of seven different Candida species and to compare the virulence in vivo with the in vitro production of proteinases and phospholipases, hemolytic activity and biofilm development capacity. One culture collection strain of each of seven Candida species (C. albicans, Candida dubliniensis, Candida glabrata, Candida krusei, Candida metapsilosis, Candida orthopsilosis and Candida parapsilosis) was studied. A double mutant C. elegans AU37 strain (glp-4;sek-1) was infected with Candida by ingestion, and the analysis of nematode survival was performed in liquid medium every 24 h until 120 h. Candida establishes a persistent lethal infection in the C. elegans intestinal tract. C. albicans and C. krusei were the most pathogenic species, whereas C. dubliniensis infection showed the lowest mortality. C. albicans was the only species with phospholipase activity, was the greatest producer of aspartyl proteinase and had a higher hemolytic activity. C. albicans and C. krusei caused higher mortality than the rest of the Candida species studied in the C. elegans model of candidiasis.

A Novel Hybrid Iron Regulation Network Combines Features from Pathogenic and Nonpathogenic Yeasts

PubMed Central

Gerwien, Franziska; Safyan, Abu; Wisgott, Stephanie; Hille, Fabrice; Kaemmer, Philipp; Linde, Jörg; Brunke, Sascha; Kasper, Lydia

2016-01-01

ABSTRACT Iron is an essential micronutrient for both pathogens and their hosts, which restrict iron availability during infections in an effort to prevent microbial growth. Successful human pathogens like the yeast Candida glabrata have thus developed effective iron acquisition strategies. Their regulation has been investigated well for some pathogenic fungi and in the model organism Saccharomyces cerevisiae, which employs an evolutionarily derived system. Here, we show that C. glabrata uses a regulation network largely consisting of components of the S. cerevisiae regulon but also of elements of other pathogenic fungi. Specifically, similarly to baker’s yeast, Aft1 is the main positive regulator under iron starvation conditions, while Cth2 degrades mRNAs encoding iron-requiring enzymes. However, unlike the case with S. cerevisiae, a Sef1 ortholog is required for full growth under iron limitation conditions, making C. glabrata an evolutionary intermediate to SEF1-dependent fungal pathogens. Therefore, C. glabrata has evolved an iron homeostasis system which seems to be unique within the pathogenic fungi. PMID:27795405

Candida albicans and Enterococcus faecalis in the gut: synergy in commensalism?

PubMed

Garsin, Danielle A; Lorenz, Michael C

2013-01-01

The fungus Candida albicans and the gram-positive bacterium Enterococcus faecalis are both normal residents of the human gut microbiome and cause opportunistic disseminated infections in immunocompromised individuals. Using a nematode infection model, we recently showed that co-infection resulted in less pathology and less mortality than infection with either species alone and this was partly explained by an interkingdom signaling event in which a bacterial-derived product inhibits hyphal morphogenesis of C. albicans. In this addendum we discuss these findings in the contest of other described bacterial-fungal interactions and recent data suggesting a potentially synergistic relationship between these two species in the mouse gut as well. We suggest that E. faecalis and C. albicans promote a mutually beneficial association with the host, in effect choosing a commensal lifestyle over a pathogenic one.

From Lipid Homeostasis to Differentiation: Old and New Functions of the Zinc Cluster Proteins Ecm22, Upc2, Sut1 and Sut2.

PubMed

Joshua, Ifeoluwapo Matthew; Höfken, Thomas

2017-04-05

Zinc cluster proteins are a large family of transcriptional regulators with a wide range of biological functions. The zinc cluster proteins Ecm22, Upc2, Sut1 and Sut2 have initially been identified as regulators of sterol import in the budding yeast Saccharomyces cerevisiae . These proteins also control adaptations to anaerobic growth, sterol biosynthesis as well as filamentation and mating. Orthologs of these zinc cluster proteins have been identified in several species of Candida . Upc2 plays a critical role in antifungal resistance in these important human fungal pathogens. Upc2 is therefore an interesting potential target for novel antifungals. In this review we discuss the functions, mode of actions and regulation of Ecm22, Upc2, Sut1 and Sut2 in budding yeast and Candida .

Candida albicans and Enterococcus faecalis in the gut

PubMed Central

Garsin, Danielle A; Lorenz, Michael C

2013-01-01

The fungus Candida albicans and the gram-positive bacterium Enterococcus faecalis are both normal residents of the human gut microbiome and cause opportunistic disseminated infections in immunocompromised individuals. Using a nematode infection model, we recently showed that co-infection resulted in less pathology and less mortality than infection with either species alone and this was partly explained by an interkingdom signaling event in which a bacterial-derived product inhibits hyphal morphogenesis of C. albicans. In this addendum we discuss these findings in the contest of other described bacterial-fungal interactions and recent data suggesting a potentially synergistic relationship between these two species in the mouse gut as well. We suggest that E. faecalis and C. albicans promote a mutually beneficial association with the host, in effect choosing a commensal lifestyle over a pathogenic one. PMID:23941906

Proteome analysis of the Albugo candida–Brassica juncea pathosystem reveals that the timing of the expression of defence-related genes is a crucial determinant of pathogenesis

PubMed Central

Kaur, Parwinder; Jost, Ricarda; Sivasithamparam, Krishnapillai; Barbetti, Martin John

2011-01-01

White rust, caused by Albugo candida, is a serious pathogen of Brassica juncea (Indian mustard) and poses a potential hazard to the presently developing canola-quality B. juncea industry worldwide. A comparative proteomic study was undertaken to explore the molecular mechanisms that underlie the defence responses of Brassica juncea to white rust disease caused by the biotrophic oomycete Albugo candida. Nineteen proteins showed reproducible differences in abundance between a susceptible (RH 819) and a resistant variety (CBJ 001) of B. juncea following inoculation with A. candida. The identities of all 19 proteins were successfully established through Q-TOF MS/MS. Five of these proteins were only detected in the resistant variety and showed significant differences in their abundance at various times following pathogen inoculation in comparison to mock-inoculated plants. Among these was a thaumatin-like protein (PR-5), a protein not previously associated with the resistance of B. juncea towards A. candida. One protein, peptidyl-prolyl cis/trans isomerase (PPIase) isoform CYP20-3, was only detected in the susceptible variety and increased in abundance in response to the pathogen. PPIases have recently been discovered to play an important role in pathogenesis by suppressing the host cell's immune response. For a subset of seven proteins examined in more detail, an increase in transcript abundance always preceded their induction at the proteome level. These findings are discussed within the context of the A. candida–Brassica juncea pathosystem, especially in relation to host resistance to this pathogen. PMID:21193577

The Wor1-like protein Fgp1 regulates pathogenicity, toxin synthesis and reproduction in the phytopathogenic fungus Fusarium graminearum

USDA-ARS?s Scientific Manuscript database

WOR1 is a gene for a conserved fungal regulatory protein controlling the dimorphic switch and pathogenicity in Candida albicans and its ortholog in the plant pathogen Fusarium oxysporum, called SGE1, is also required for pathogenicity and expression of plant effector proteins. F. graminearum, an imp...

Use of CHROMagar Candida for the presumptive identification of Candida species directly from clinical specimens in resource-limited settings.

PubMed

Nadeem, Sayyada Ghufrana; Hakim, Shazia Tabassum; Kazmi, Shahana Urooj

2010-02-09

Identification of yeast isolated from clinical specimens to the species level has become increasingly important. Ever-increasing numbers of immuno-suppressed patients, a widening range of recognized pathogens, and the discovery of resistance to antifungal drugs are contributing factors to this necessity. A total of 487 yeast strains were studied for the primary isolation and presumptive identification, directly from clinical specimen. Efficacy of CHROMagar Candida has been evaluated with conventional methods including morphology on Corn meal-tween 80 agar and biochemical methods by using API 20 C AUX. The result of this study shows that CHROMagar Candida can easily identify three species of Candida on the basis of colonial color and morphology, and accurately differentiate between them i.e. Candida albicans, Candida tropicalis, and Candida krusei. The specificity and sensitivity of CHROMagar Candida for C. albicans calculated as 99%, for C. tropicalis calculated as 98%, and C. krusei it is 100%. The data presented supports the use of CHROMagar Candida for the rapid identification of Candida species directly from clinical specimens in resource-limited settings, which could be very helpful in developing appropriate therapeutic strategy and management of patients.

Survival of Human Pathogens in Composted Sewage

PubMed Central

Wiley, B. Beauford; Westerberg, Stephen C.

1969-01-01

Studies were conducted to assess the effectiveness of an aerobic composter in destroying pathogens that may possibly be present in raw sewage sludge. Experiments conducted in this study were designed to determine whether or not selected indicator organisms (i.e., Salmonella newport, poliovirus type 1, Ascaris lumbricoides ova, and Candida albicans) could survive the composting process. The results of the assay showed that after 43 hr of composting, no viable indicator organisms could be detected. The poliovirus type I was the most sensitive, being inactivated within the first hour, whereas C. albicans was the most resistant, requiring more than 28 hr of composting for its inactivation. The data from this study indicated that aerobic composting of sewage sludge would destroy the indicator pathogens when a temperature of 60 to 70 C is maintained for a period of 3 days. PMID:4313209

Fungal model systems and the elucidation of pathogenicity determinants

PubMed Central

Perez-Nadales, Elena; Almeida Nogueira, Maria Filomena; Baldin, Clara; Castanheira, Sónia; El Ghalid, Mennat; Grund, Elisabeth; Lengeler, Klaus; Marchegiani, Elisabetta; Mehrotra, Pankaj Vinod; Moretti, Marino; Naik, Vikram; Oses-Ruiz, Miriam; Oskarsson, Therese; Schäfer, Katja; Wasserstrom, Lisa; Brakhage, Axel A.; Gow, Neil A.R.; Kahmann, Regine; Lebrun, Marc-Henri; Perez-Martin, José; Di Pietro, Antonio; Talbot, Nicholas J.; Toquin, Valerie; Walther, Andrea; Wendland, Jürgen

2014-01-01

Fungi have the capacity to cause devastating diseases of both plants and animals, causing significant harvest losses that threaten food security and human mycoses with high mortality rates. As a consequence, there is a critical need to promote development of new antifungal drugs, which requires a comprehensive molecular knowledge of fungal pathogenesis. In this review, we critically evaluate current knowledge of seven fungal organisms used as major research models for fungal pathogenesis. These include pathogens of both animals and plants; Ashbya gossypii, Aspergillus fumigatus, Candida albicans, Fusarium oxysporum, Magnaporthe oryzae, Ustilago maydis and Zymoseptoria tritici. We present key insights into the virulence mechanisms deployed by each species and a comparative overview of key insights obtained from genomic analysis. We then consider current trends and future challenges associated with the study of fungal pathogenicity. PMID:25011008

Azole drugs are imported by facilitated diffusion in Candida albicans and other pathogenic fungi.

PubMed

Mansfield, Bryce E; Oltean, Hanna N; Oliver, Brian G; Hoot, Samantha J; Leyde, Sarah E; Hedstrom, Lizbeth; White, Theodore C

2010-09-30

Despite the wealth of knowledge regarding the mechanisms of action and the mechanisms of resistance to azole antifungals, very little is known about how the azoles are imported into pathogenic fungal cells. Here the in-vitro accumulation and import of Fluconazole (FLC) was examined in the pathogenic fungus, Candida albicans. In energized cells, FLC accumulation correlates inversely with expression of ATP-dependent efflux pumps. In de-energized cells, all strains accumulate FLC, suggesting that FLC import is not ATP-dependent. The kinetics of import in de-energized cells displays saturation kinetics with a K(m) of 0.64 μM and V(max) of 0.0056 pmol/min/10⁸ cells, demonstrating that FLC import proceeds via facilitated diffusion through a transporter rather than passive diffusion. Other azoles inhibit FLC import on a mole/mole basis, suggesting that all azoles utilize the same facilitated diffusion mechanism. An analysis of related compounds indicates that competition for azole import depends on an aromatic ring and an imidazole or triazole ring together in one molecule. Import of FLC by facilitated diffusion is observed in other fungi, including Cryptococcus neoformans, Saccharomyces cerevisiae, and Candida krusei, indicating that the mechanism of transport is conserved among fungal species. FLC import was shown to vary among Candida albicans resistant clinical isolates, suggesting that altered facilitated diffusion may be a previously uncharacterized mechanism of resistance to azole drugs.

Candida lusitaniae causing fatal meningitis.

PubMed Central

Sarma, P. S.; Durairaj, P.; Padhye, A. A.

1993-01-01

Fatal meningitis due to Candida lusitaniae in a 35 year old previously healthy man is described. C. lusitaniae is an opportunistic fungal pathogen reported infrequently in the English literature. This is the third case report of meningitis and the first fatal infection in an adult from Central India due to C. lusitaniae known to the authors. PMID:8290437

Hyperspectral fluorescence microscopy detects autofluorescent factors that can be exploited as a diagnostic method for Candida species differentiation

NASA Astrophysics Data System (ADS)

Graus, Matthew S.; Neumann, Aaron K.; Timlin, Jerilyn A.

2017-01-01

Fungi in the Candida genus are the most common fungal pathogens. They not only cause high morbidity and mortality but can also cost billions of dollars in healthcare. To alleviate this burden, early and accurate identification of Candida species is necessary. However, standard identification procedures can take days and have a large false negative error. The method described in this study takes advantage of hyperspectral confocal fluorescence microscopy, which enables the capability to quickly and accurately identify and characterize the unique autofluorescence spectra from different Candida species with up to 84% accuracy when grown in conditions that closely mimic physiological conditions.

Secreted aspartic proteases are not required for invasion of reconstituted human epithelia by Candida albicans.

PubMed

Lermann, Ulrich; Morschhäuser, Joachim

2008-11-01

A well-known virulence attribute of the human-pathogenic yeast Candida albicans is the secretion of aspartic proteases (Saps), which may contribute to colonization and infection of different host niches by degrading tissue barriers, destroying host defence molecules, or digesting proteins for nutrient supply. The role of individual Sap isoenzymes, which are encoded by a large gene family, for the pathogenicity of C. albicans has been investigated by assessing the virulence of mutants lacking specific SAP genes and by studying the expression pattern of the SAP genes in various models of superficial and systemic infections. We used a recombination-based genetic reporter system to detect the induction of the SAP1-SAP6 genes during infection of reconstituted human vaginal epithelium. Only SAP5, but none of the other tested SAP genes, was detectably activated in this in vitro infection model. To directly address the importance of the SAP1-SAP6 genes for invasion of reconstituted human epithelia (RHE), we constructed a set of mutants of the wild-type C. albicans model strain SC5314 in which either single or multiple SAP genes were specifically deleted. Even mutants lacking all of the SAP1-SAP3 or the SAP4-SAP6 genes displayed the same capacity to invade and damage both oral and vaginal RHE as their wild-type parental strain, in contrast to a nonfilamentous efg1Delta mutant that was avirulent under these conditions. We therefore conclude from these results that the secreted aspartic proteases Sap1p-Sap6p are not required for invasion of RHE by C. albicans.

VT-1161 protects mice against oropharyngeal candidiasis caused by fluconazole-susceptible and -resistant Candida albicans

PubMed Central

Break, Timothy J; Desai, Jigar V; Ferre, Elise M N; Henderson, Christina; Zelazny, Adrian M; Siebenlist, Ulrich; Hoekstra, William J; Schotzinger, Robert J; Garvey, Edward P; Lionakis, Michail S

2018-01-01

Abstract Background Candida albicans, the most common human fungal pathogen, causes chronic mucosal infections in patients with inborn errors of IL-17 immunity that rely heavily on chronic, often lifelong, azole antifungal agents for treatment. However, a rise in azole resistance has predicated a need for developing new antifungal drugs. Objectives To test the in vitro and in vivo efficacy of VT-1161 and VT-1129 in the treatment of oropharyngeal candidiasis with azole-susceptible or -resistant C. albicans strains. Methods MICs of VT-1161, VT-1129 and nine licensed antifungal drugs were determined for 31 Candida clinical isolates. The drug concentrations in mouse serum and tongues were measured following oral administration. IL-17-signalling-deficient Act1−/− mice were infected with fluconazole-susceptible or fluconazole-resistant C. albicans strains, and the amount of mucosal fungal burden was determined after fluconazole or VT-1161 treatment. Results Fourteen isolates (45%) were not fluconazole susceptible (MIC ≥4 mg/L). VT-1161 and VT-1129 showed significant in vitro activity against the majority of the 31 mucosal clinical isolates (MIC50 0.03 and 0.06 mg/L, respectively), including Candida glabrata (MIC50, 0.125 and 0.25 mg/L, respectively). After oral doses, VT-1161 and VT-1129 concentrations in mouse serum and tongues were well above their MIC50 values. VT-1161 was highly effective as treatment of both fluconazole-susceptible and -resistant oropharyngeal candidiasis in Act1−/− mice. Conclusions VT-1129 and VT-1161 exhibit significant in vitro activity against Candida strains, including fluconazole-resistant C. albicans and C. glabrata. VT-1161 administration in mice results in significant mucosal drug accumulation and eradicates infection caused by fluconazole-susceptible and -resistant Candida strains. PMID:29040636

Pathogenic characteristics of Candida albicans isolated from oral cavities of denture wearers and cancer patients wearing oral prostheses.

PubMed

Mothibe, J V; Patel, M

2017-09-01

Candida albicans cause opportunistic infections including oral candidiasis in immunocompromised patients. It has an ability to cause infection due to its virulence factors. This study investigated the pathogenic characteristics of C. albicans isolated from the oral cavities of healthy subjects and two vulnerable groups, denture wearers and cancer patients wearing oral prostheses. Oral rinse samples were collected and cultured for the quantitative and qualitative analysis of Candida. Twenty strains of C. albicans isolated from the healthy individuals and denture wearers and, 14 strains isolated from the cancer patients were selected and their pathogenic characteristics were measured. The results of the study groups were compared using a Scheffe test for pairwise comparison and a chi square test. Denture wearer and cancer patients with prostheses carried significantly higher number (p < 0.01) and a variety of Candida than the normal individuals. Denture wearer and cancer patients carried several Candida species. The adherence abilities (p = 0.01) as well as phospholipase (p < 0.01) and proteinase (p = 0.03) production were significantly higher in the strains from denture wearers. In addition, high number of isolates from the denture wearers produced phospholipase and proteinase (85% and 80% respectively) compared to the strains from normal subjects (25% and 60% respectively). Only the germ tube formation and adherence ability were significantly higher in the strains from the cancer patients with prostheses (p = 0.05 and p < 0.01 respectively). In conclusion, during the commensal state, the increased expression of virulence factors in the denture wearers suggests the readiness of these strains to cause infection in this group. The high number of C. albicans and their increased adherence ability in the two study groups suggest that hygiene of oral cavity and prostheses is important in the prevention of colonization of Candida and the development of oral candidiasis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Simultaneous cytofluorometric measurement of phagocytosis, burst production and killing of human phagocytes using Candida albicans and Staphylococcus aureus as target organisms.

PubMed

Salih, H R; Husfeld, L; Adam, D

2000-05-01

Polymorphonuclear leukocytes (PMN) play a central role in the elimination of most extracellular pathogens, and an impairment of their functions predisposes an individual towards local and systemic bacterial and fungal infections. Here we describe a rapid and easy-to-perform cytofluorometric assay for investigation of PMN activity using Candida albicans and Staphylococcus aureus as target organisms. Phagocytes were stained with anti-CD13-RPE antibody, and microorganisms were stained with calcein-AM. Oxidative burst production was measured by oxidation of dihydroethidium. The percentage of killed target organisms after ingestion was determined by staining with ethidium-homodimer-1 after lysis of human cells. The dyes and procedures used in this method were chosen after comparison of different stains and cell preparation techniques described in previous assays. Concerning phagocytosis, the percentages of active phagocytes and of ingested microorganisms were determined. Furthermore, the method allowed measurement of the resulting percentage of PMNs producing respiratory burst, and of the percentage of killed microorganisms. We minimized artifactual changes, which might have been the reason for the difficulties and conflicting results of other cytofluorometric methods. The described method provides a new whole blood cytofluorometric assay, which combines rapid and simple handling with high reproducibility of results obtained by investigation of PMN activity using Candida albicans and Staphylococcus aureus as target organisms.

Manipulation of Host Diet To Reduce Gastrointestinal Colonization by the Opportunistic Pathogen Candida albicans

PubMed Central

Tornberg-Belanger, Stephanie N.; Matthan, Nirupa R.; Lichtenstein, Alice H.

2015-01-01

ABSTRACT Candida albicans, the most common human fungal pathogen, can cause systemic infections with a mortality rate of ~40%. Infections arise from colonization of the gastrointestinal (GI) tract, where C. albicans is part of the normal microflora. Reducing colonization in at-risk patients using antifungal drugs prevents C. albicans-associated mortalities. C. albicans provides a clinically relevant system for studying the relationship between diet and the microbiota as it relates to commensalism and pathogenicity. As a first step toward a dietary intervention to reduce C. albicans GI colonization, we investigated the impact of dietary lipids on murine colonization by C. albicans. Coconut oil and its constituent fatty acids have antifungal activity in vitro; we hypothesized that dietary coconut oil would reduce GI colonization by C. albicans. Colonization was lower in mice fed a coconut oil-rich diet than in mice fed diets rich in beef tallow or soybean oil. Switching beef tallow-fed mice to a coconut oil diet reduced preexisting colonization. Coconut oil reduced colonization even when the diet also contained beef tallow. Dietary coconut oil also altered the metabolic program of colonizing C. albicans cells. Long-chain fatty acids were less abundant in the cecal contents of coconut oil-fed mice than in the cecal contents of beef tallow-fed mice; the expression of genes involved in fatty acid utilization was lower in C. albicans from coconut oil-fed mice than in C. albicans from beef tallow-fed mice. Extrapolating to humans, these findings suggest that coconut oil could become the first dietary intervention to reduce C. albicans GI colonization. IMPORTANCE Candida albicans, the most common human fungal pathogen, can cause infections with a mortality rate of ~40%. C. albicans is part of the normal gut flora, but when a patient’s immune system is compromised, it can leave the gut and cause infections. By reducing the amount of C. albicans in the gut of susceptible patients, infections (and the resulting fatalities) can be prevented. Currently, this is done using antimicrobial drugs; to “preserve” drugs for treating infections, we looked for a dietary change to reduce the amount of C. albicans in the gut. Using a mouse model, we showed that adding coconut oil to the diet could become the first drug-free way to reduce C. albicans in the gut. More broadly, this model lets us study the interactions between our diet and the microbes in our body and the reasons why some of those microbes, under certain conditions, cause disease. Podcast: A podcast concerning this article is available. PMID:27303684

Oropharyngeal candidiasis in head and neck cancer patients in Iran: Species identification, antifungal susceptibility and pathogenic characterization.

PubMed

Jahanshiri, Z; Manifar, S; Moosa, H; Asghari-Paskiabi, F; Mahmoodzadeh, H; Shams-Ghahfarokhi, M; Razzaghi-Abyaneh, M

2018-06-01

Oropharyngeal candidiasis (OPC) is the most frequent opportunistic fungal infection in head and neck cancer patients. This study was done to identify the Candida species, which cause OPC, and to evaluate their antifungal susceptibility pattern and pathogenic characteristics in Iranian head and neck cancer patients treated by radiotherapy. The oral clinical samples were determined by culturing on CHROMagar, carbohydrate assimilation and ITS sequencing methods. Biofilm formation, phospholipase and proteinase activity and antifungal susceptibility were examined too. Among 54 patients with confirmed OPC, 39 (72.22%) patients were male and 15 (27.77%) were female. The most frequently Candida species from a total of 60 isolates was C. albicans (53.3%), followed by C. tropicalis (21.66%), C. glabrata (15%), C. kefyr (5%) and C. dubliniensis (1.66%). All the isolates were high-producers of biofilm. All of Candida isolates were proteinase positive and 47 isolates (81.04%) represented phospholipase activity. The maximum and minimum rates of antifungal resistance belonged to ketoconazole (93.75% of C. albicans and 89.28% of Candida non-albicans) and fluconazole (62.50% and 42.85% of C. albicans and Candida non-albicans), respectively. The most effective antifungal against all candida isolates was fluconazole. Our data can estimate abundance of OPC in male and female head and neck cancer patients and is helpful to use effective strategies for antifungal treatment, prophylaxis, and preventive therapies in these patients. Copyright © 2018. Published by Elsevier Masson SAS.

Development of a specific polymerase chain reaction assay for the detection of Basidiobolus.

PubMed

Gómez-Muñoz, María Teresa; Fernández-Barredo, Salceda; Martínez-Díaz, Rafael Alberto; Pérez-Gracia, María Teresa; Ponce-Gordo, Francisco

2012-01-01

The etiology of chronic diarrhea is complex in humans and animals. It is always necessary to evaluate a list of differential diagnosis, including bacteria, protozoa and fungi. Basidiobolomycosis is a fungal disease reported sporadically worldwide, mainly caused by B. ranarum, a frequent organism found in soil or in the intestine and skin of lizards and frogs. It is an opportunistic pathogen that causes infections characterized by granulomatous lesions in the subcutaneous tissues as well as in the intestinal wall in humans and animals. In this work we have developed a PCR technique to differentiate Basidiobolus from other causes of intestinal disease in dogs and humans. To test the specificity of the PCR assay we included closely related organisms, common intestinal microbiota and pathogenic organisms, such as Aspergillus, Candida, Cryptosporidium, Escherichia, Giardia, Mucor, Proteus, Rhizopus and Salmonella. Pythium insidiosum, which cause clinically similar disease in dogs but require a different treatment. Only Basidiobolus was positive to the PCR assay.

A Case Report of Penile Infection Caused by Fluconazole- and Terbinafine-Resistant Candida albicans.

PubMed

Hu, Yongxuan; Hu, Yanqing; Lu, Yan; Huang, Shiyun; Liu, Kangxing; Han, Xue; Mao, Zuhao; Wu, Zhong; Zhou, Xianyi

2017-04-01

Candida albicans is the most common pathogen that causes balanoposthitis. It often causes recurrence of symptoms probably due to its antifungal resistance. A significant number of balanitis Candida albicans isolates are resistant to azole and terbinafine antifungal agents in vitro. However, balanoposthitis caused by fluconazole- and terbinafine-resistant Candida albicans has rarely been reported. Here, we describe a case of a recurrent penile infection caused by fluconazole- and terbinafine-resistant Candida albicans, as well as the treatments administered to this patient. The isolate from the patient was tested for drug susceptibility in vitro. It was sensitive to itraconazole, voriconazole, clotrimazole and amphotericin B, but not to terbinafine and fluconazole. Thus, oral itraconazole was administrated to this patient with resistant Candida albicans penile infection. The symptoms were improved, and mycological examination result was negative. Follow-up treatment of this patient for 3 months showed no recurrence.

Synergistic Effects and Mechanisms of Budesonide in Combination with Fluconazole against Resistant Candida albicans.

PubMed

Li, Xiuyun; Yu, Cuixiang; Huang, Xin; Sun, Shujuan

2016-01-01

Candida albicans is an important opportunistic pathogen, causing both superficial mucosal infections and life-threatening systemic diseases in the clinic. The emergence of drug resistance in Candida albicans has become a noteworthy phenomenon due to the extensive use of antifungal agents and the development of biofilms. This study showed that budesonide potentiates the antifungal effect of fluconazole against fluconazole-resistant Candida albicans strains both in vitro and in vivo. In addition, our results demonstrated, for the first time, that the combination of fluconazole and budesonide can reverse the resistance of Candida albicans by inhibiting the function of drug transporters, reducing the formation of biofilms, promoting apoptosis and inhibiting the activity of extracellular phospholipases. This is the first study implicating the effects and mechanisms of budesonide against Candida albicans alone or in combination with fluconazole, which may ultimately lead to the identification of new potential antifungal targets.

PCR-denaturing gradient gel electrophoresis analysis of microbial community in soy-daddawa, a Nigerian fermented soybean (Glycine max (L.) Merr.) condiment.

PubMed

Ezeokoli, Obinna T; Gupta, Arvind K; Mienie, Charlotte; Popoola, Temitope O S; Bezuidenhout, Cornelius C

2016-03-02

Soy-daddawa, a fermented soybean (Glycine max (L.) Merr.) condiment, plays a significant role in the culinary practice of West Africa. It is essential to understand the microbial community of soy-daddawa for a successful starter culture application. This study investigated the microbial community structure of soy-daddawa samples collected from Nigerian markets, by PCR-denaturing gradient gel electrophoresis (DGGE) targeting the V3-V5 region of the 16S rRNA gene of bacteria and internal transcribed spacer 2 (ITS2) region of fungi. Six bacterial and 16 fungal (nine yeasts and seven molds) operational taxonomic units (OTUs)/species were obtained at 97% sequence similarity. Taxonomic assignments revealed that bacterial OTUs belonged to the phyla Firmicutes and Actinobacteria, and included species from the genera Atopostipes, Bacillus, Brevibacterium and Nosocomiicoccus. Densitometric analysis of DGGE image/bands revealed that Bacillus spp. were the dominant OTU/species in terms of population numbers. Fungal OTUs belonged to the phyla Ascomycota and Zygomycota, and included species from the genera, Alternaria, Aspergillus, Candida, Cladosporium, Dokmaia, Issatchenkia, Kodamaea, Lecythophora, Phoma, Pichia, Rhizopus, Saccharomyces and Starmerella. The majority of fungal species have not been previously reported in soy-daddawa. Potential opportunistic human pathogens such as Atopostipes suicloacalis, Candida rugosa, Candida tropicalis, and Kodamaea ohmeri were detected. Variation in soy-daddawa microbial communities amongst samples and presence of potential opportunistic pathogens emphasises the need for starter culture employment and good handling practices in soy-daddawa processing. Copyright © 2016 Elsevier B.V. All rights reserved.

[Yeast species in vulvovaginitis candidosa].

PubMed

Nemes-Nikodém, Éva; Tamási, Béla; Mihalik, Noémi; Ostorházi, Eszter

2015-01-04

Vulvovaginal candidiasis is the most common mycosis, however, the available information about antifungal susceptibilities of these yeasts is limited. To compare the gold standard fungal culture with a new molecular identification method and report the incidence of yeast species in vulvovaginitis candidosa. The authors studied 370 yeasts isolated from vulvovaginal candidiasis and identified them by phenotypic and molecular methods. The most common species was Candida albicans (85%), followed by Candida glabrata, and other Candida species. At present there are no recommendations for the evaluation of antifungal susceptibility of pathogenic fungal species occurring in vulvovaginal candidiasis and the natural antifungal resistance of the different species is known only. Matrix Assisted Laser Desorption Ionization Time of Flight identification can be used to differentiate the fluconazole resistant Candida dubliniensis and the sensitive Candida albicans strains.

Differential Microbial Diversity in Drosophila melanogaster: Are Fruit Flies Potential Vectors of Opportunistic Pathogens?

PubMed Central

Maldonado-Morales, Génesis; Bayman, Paul

2017-01-01

Drosophila melanogaster has become a model system to study interactions between innate immunity and microbial pathogens, yet many aspects regarding its microbial community and interactions with pathogens remain unclear. In this study wild D. melanogaster were collected from tropical fruits in Puerto Rico to test how the microbiota is distributed and to compare the culturable diversity of fungi and bacteria. Additionally, we investigated whether flies are potential vectors of human and plant pathogens. Eighteen species of fungi and twelve species of bacteria were isolated from wild flies. The most abundant microorganisms identified were the yeast Candida inconspicua and the bacterium Klebsiella sp. The yeast Issatchenkia hanoiensis was significantly more common internally than externally in flies. Species richness was higher in fungi than in bacteria, but diversity was lower in fungi than in bacteria. The microbial composition of flies was similar internally and externally. We identified a variety of opportunistic human and plant pathogens in flies such as Alcaligenes faecalis, Aspergillus flavus, A. fumigatus, A. niger, Fusarium equiseti/oxysporum, Geotrichum candidum, Klebsiella oxytoca, Microbacterium oxydans, and Stenotrophomonas maltophilia. Despite its utility as a model system, D. melanogaster can be a vector of microorganisms that represent a potential risk to plant and public health. PMID:29234354

Chemical screening identifies filastatin, a small molecule inhibitor of Candida albicans adhesion, morphogenesis, and pathogenesis.

PubMed

Fazly, Ahmed; Jain, Charu; Dehner, Amie C; Issi, Luca; Lilly, Elizabeth A; Ali, Akbar; Cao, Hong; Fidel, Paul L; Rao, Reeta P; Kaufman, Paul D

2013-08-13

Infection by pathogenic fungi, such as Candida albicans, begins with adhesion to host cells or implanted medical devices followed by biofilm formation. By high-throughput phenotypic screening of small molecules, we identified compounds that inhibit adhesion of C. albicans to polystyrene. Our lead candidate compound also inhibits binding of C. albicans to cultured human epithelial cells, the yeast-to-hyphal morphological transition, induction of the hyphal-specific HWP1 promoter, biofilm formation on silicone elastomers, and pathogenesis in a nematode infection model as well as alters fungal morphology in a mouse mucosal infection assay. We term this compound filastatin based on its strong inhibition of filamentation, and we use chemical genetic experiments to show that it acts downstream of multiple signaling pathways. These studies show that high-throughput functional assays targeting fungal adhesion can provide chemical probes for study of multiple aspects of fungal pathogenesis.

Chemical screening identifies filastatin, a small molecule inhibitor of Candida albicans adhesion, morphogenesis, and pathogenesis

PubMed Central

Fazly, Ahmed; Jain, Charu; Dehner, Amie C.; Issi, Luca; Lilly, Elizabeth A.; Ali, Akbar; Cao, Hong; Fidel, Paul L.; P. Rao, Reeta; Kaufman, Paul D.

2013-01-01

Infection by pathogenic fungi, such as Candida albicans, begins with adhesion to host cells or implanted medical devices followed by biofilm formation. By high-throughput phenotypic screening of small molecules, we identified compounds that inhibit adhesion of C. albicans to polystyrene. Our lead candidate compound also inhibits binding of C. albicans to cultured human epithelial cells, the yeast-to-hyphal morphological transition, induction of the hyphal-specific HWP1 promoter, biofilm formation on silicone elastomers, and pathogenesis in a nematode infection model as well as alters fungal morphology in a mouse mucosal infection assay. We term this compound filastatin based on its strong inhibition of filamentation, and we use chemical genetic experiments to show that it acts downstream of multiple signaling pathways. These studies show that high-throughput functional assays targeting fungal adhesion can provide chemical probes for study of multiple aspects of fungal pathogenesis. PMID:23904484

Cell damage caused by vaginal Candida albicans isolates from women with different symptomatologies.

PubMed

Faria, Daniella Renata; Sakita, Karina Mayumi; Akimoto-Gunther, Luciene Setsuko; Kioshima, Érika Seki; Svidzinski, Terezinha Inez Estivalet; Bonfim-Mendonça, Patrícia de Souza

2017-08-01

The present study aimed to characterize cell damage caused by vaginal Candida albicans isolates from women with different symptomatologies. It was evaluated 12 clinical isolates of C. albicans from vaginal samples: 4 from asymptomatic women (AS), 4 from women with a single episode of vulvovaginal candidiasis (VVC) and 4 from women with recurrent vulvovaginal candidiasis (RVVC). We evaluated the ability of C. albicans to adhere to human cervical cancer cells (SiHa), the yeast-SiHa cell interactions and cell damage. All of the clinical isolates presented a high adhesion capacity on SiHa cells. However, clinical isolates from symptomatic women (VVC and RVVC) had higher filamentation after contact (24 h) with SiHa cells and a greater capacity to cause cell damage (>80 %). Clinical isolates from symptomatic women had greater potential to invade SiHa cells, suggesting that they are more pathogenic than AS isolates.

Structure-Guided Development of Efficacious Antifungal Agents Targeting Candida Glabrata Dihydrofolate Reductase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, J.; Bolstad, D; Smith, A

2008-01-01

Candida glabrata is a lethal fungal pathogen resistant to many antifungal agents and has emerged as a critical target for drug discovery. Over the past several years, we have been developing a class of propargyl-linked antifolates as antimicrobials and hypothesized that these compounds could be effective inhibitors of dihydrofolate reductase (DHFR) from C. glabrata. We initially screened a small collection of these inhibitors and found modest levels of potency. Subsequently, we determined the crystal structure of C. glabrata DHFR bound to a representative inhibitor with data to 1.6 A resolution. Using this structure, we designed and synthesized second-generation inhibitors. Thesemore » inhibitors bind the C. glabrata DHFR enzyme with subnanomolar potency, display greater than 2000-fold levels of selectivity over the human enzyme, and inhibit the growth of C. glabrata at levels observed with clinically employed therapeutics.« less

[Antibacterial and antifungal activity of Salvia apiana against clinically important microorganisms].

PubMed

Córdova-Guerrero, Iván; Aragon-Martinez, Othoniel H; Díaz-Rubio, Laura; Franco-Cabrera, Santiago; Serafín-Higuera, Nicolas A; Pozos-Guillén, Amaury; Soto-Castro, Tely A; Martinez-Morales, Flavio; Isiordia-Espinoza, Mario

Due to the great global concern regarding bacterial resistance to antibiotics, an ongoing search for new molecules having antibacterial activity is necessary. This study evaluated the antibacterial and anticandidal effects of a hexane extract from the root of Salvia apiana. Salvia extracts at concentrations of 27, 13.5, 6.8 and 3.4mg/ml caused growth inhibition of Staphylococcus aureus, Streptococcus pyogenes, Enterococcus faecalis and Candida albicans. However, no significant effect was observed on Escherichia coli and Candida tropicalis in comparison to vehicle. It was here demonstrated for the first time that Salvia apiana has an important antimicrobial effect on human pathogens of great clinical value, thus opening the field to continue the evaluation of this lamiaceous plant for its future use as a therapeutic agent. Copyright © 2016 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

Molecular cloning and characterization of chitinase genes from Candida albicans.

PubMed

McCreath, K J; Specht, C A; Robbins, P W

1995-03-28

Chitinase (EC 3.2.1.14) is an important enzyme for the remodeling of chitin in the cell wall of fungi. We have cloned three chitinase genes (CHT1, CHT2, and CHT3) from the dimorphic human pathogen Candida albicans. CHT2 and CHT3 have been sequenced in full and their primary structures have been analyzed: CHT2 encodes a protein of 583 aa with a predicted size of 60.8 kDa; CHT3 encodes a protein of 567 aa with a predicted size of 60 kDa. All three genes show striking similarity to other chitinase genes in the literature, especially in the proposed catalytic domain. Transcription of CHT2 and CHT3 was greater when C. albicans was grown in a yeast phase as compared to a mycelial phase. A transcript of CHT1 could not be detected in either growth condition.

Association of genotypes with infection types and antifungal susceptibilities in Candida albicans as revealed by recent molecular typing strategies

PubMed Central

Bai, Feng-Yan

2014-01-01

Candida albicans is a commensal microorganism in the mucosa of healthy individuals, but is also the most common opportunistic fungal pathogen of humans. It causes from benign infections such as oral and vaginal candidiasis to fatal, systematic diseases in immunocompromised or critically ill patients. In addition to improved therapy, the rapid and accurate identification of the disease-causing strains is crucial for diagnosis, clinical treatment and epidemiological studies of candidiasis. A variety of methods for strain typing of C. albicans have been developed. The most commonly used methods with the focus on recently developed molecular typing or DNA-fingerprinting strategies and the recent findings in the association of specific and genetically similar genotypes with certain infection types and the correlation between azole susceptibilities and certain genotypes of C. albicans from China are reviewed. PMID:24772369

Structural analyses of Candida albicans sterol 14α-demethylase complexed with azole drugs address the molecular basis of azole-mediated inhibition of fungal sterol biosynthesis

PubMed Central

Hargrove, Tatiana Y.; Friggeri, Laura; Wawrzak, Zdzislaw; Qi, Aidong; Hoekstra, William J.; Schotzinger, Robert J.; York, John D.; Guengerich, F. Peter; Lepesheva, Galina I.

2017-01-01

With some advances in modern medicine (such as cancer chemotherapy, broad exposure to antibiotics, and immunosuppression), the incidence of opportunistic fungal pathogens such as Candida albicans has increased. Cases of drug resistance among these pathogens have become more frequent, requiring the development of new drugs and a better understanding of the targeted enzymes. Sterol 14α-demethylase (CYP51) is a cytochrome P450 enzyme required for biosynthesis of sterols in eukaryotic cells and is the major target of clinical drugs for managing fungal pathogens, but some of the CYP51 key features important for rational drug design have remained obscure. We report the catalytic properties, ligand-binding profiles, and inhibition of enzymatic activity of C. albicans CYP51 by clinical antifungal drugs that are used systemically (fluconazole, voriconazole, ketoconazole, itraconazole, and posaconazole) and topically (miconazole and clotrimazole) and by a tetrazole-based drug candidate, VT-1161 (oteseconazole: (R)-2-(2,4-difluorophenyl)-1,1-difluoro-3-(1H-tetrazol-1-yl)-1-(5-(4-(2,2,2-trifluoroethoxy)phenyl)pyridin-2-yl)propan-2-ol). Among the compounds tested, the first-line drug fluconazole was the weakest inhibitor, whereas posaconazole and VT-1161 were the strongest CYP51 inhibitors. We determined the X-ray structures of C. albicans CYP51 complexes with posaconazole and VT-1161, providing a molecular mechanism for the potencies of these drugs, including the activity of VT-1161 against Candida krusei and Candida glabrata, pathogens that are intrinsically resistant to fluconazole. Our comparative structural analysis outlines phylum-specific CYP51 features that could direct future rational development of more efficient broad-spectrum antifungals. PMID:28258218

Structural analyses of Candida albicans sterol 14α-demethylase complexed with azole drugs address the molecular basis of azole-mediated inhibition of fungal sterol biosynthesis.

PubMed

Hargrove, Tatiana Y; Friggeri, Laura; Wawrzak, Zdzislaw; Qi, Aidong; Hoekstra, William J; Schotzinger, Robert J; York, John D; Guengerich, F Peter; Lepesheva, Galina I

2017-04-21

With some advances in modern medicine (such as cancer chemotherapy, broad exposure to antibiotics, and immunosuppression), the incidence of opportunistic fungal pathogens such as Candida albicans has increased. Cases of drug resistance among these pathogens have become more frequent, requiring the development of new drugs and a better understanding of the targeted enzymes. Sterol 14α-demethylase (CYP51) is a cytochrome P450 enzyme required for biosynthesis of sterols in eukaryotic cells and is the major target of clinical drugs for managing fungal pathogens, but some of the CYP51 key features important for rational drug design have remained obscure. We report the catalytic properties, ligand-binding profiles, and inhibition of enzymatic activity of C. albicans CYP51 by clinical antifungal drugs that are used systemically (fluconazole, voriconazole, ketoconazole, itraconazole, and posaconazole) and topically (miconazole and clotrimazole) and by a tetrazole-based drug candidate, VT-1161 (oteseconazole: ( R )-2-(2,4-difluorophenyl)-1,1-difluoro-3-(1 H -tetrazol-1-yl)-1-(5-(4-(2,2,2-trifluoroethoxy)phenyl)pyridin-2-yl)propan-2-ol). Among the compounds tested, the first-line drug fluconazole was the weakest inhibitor, whereas posaconazole and VT-1161 were the strongest CYP51 inhibitors. We determined the X-ray structures of C. albicans CYP51 complexes with posaconazole and VT-1161, providing a molecular mechanism for the potencies of these drugs, including the activity of VT-1161 against Candida krusei and Candida glabrata , pathogens that are intrinsically resistant to fluconazole. Our comparative structural analysis outlines phylum-specific CYP51 features that could direct future rational development of more efficient broad-spectrum antifungals. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

[Water fungi occurence in the River Supraśl-bath Jurowce near Białystok].

PubMed

Kiziewicz, Bozena; Kozłowska, Mariola; Godlewska, Anna; Muszyńvska, Elzbieta; Mazalska, Bozenna

2004-01-01

Studies on the occurrence of aquatic fungi in the bathing sites of the Supraśl River in Jurowce village were collected in years 2000-2003. Hydrochemical analysis was performed using standard methods. Bait method was used to isolate the fungi. In the Supraśl River at Jurowce village 36 fungi species were identified, among them fish pathogens Achlya orion, Aphanomyces laevis, Dictyuchus monosporus, Saprolegnia ferax, Saprolegnia monoica, S. parasitica, human pathogens Aspergillus flavus, Candida albicans, Lagenidium humanum, Penicillium mycetomagenum, Rhizophydium keratinophilum and Trichosporon cutaneum, phytopathogens Achlya racemosa, Phytophthora gonapodoides, Pythium butleri, P. myriotylum and P. debaryanum. Physicochemical parameters of waters in Supraśl River-bathing sites had no important effect on the occurrence of fungi.

Expression of Candida glabrata adhesins following exposure to chemical preservatives

PubMed Central

Mundy, Renee Domergue; Cormack, Brendan

2014-01-01

In Candida glabrata, an opportunistic yeast pathogen, adherence to host cells is mediated in part by the Epa family of adhesins, which are encoded largely at subtelomeric loci where they are subject to transcriptional silencing. In analyzing the regulation of the subtelomeric EPA6 gene, we found that its transcription is highly induced after exposure to methylparaben, propylparaben or sorbate. These weak acid-related chemicals are widely used as antifungal preservatives in many consumer goods, including over-the-counter (OTC) vaginal products. Culture of C. glabrata in a variety of vaginal products induced expression of EPA6, leading to increased adherence to cultured human cells as well as primary human vaginal epithelial cells. We present evidence that paraben/sorbate-induction of EPA6 expression involves both preservative stress and growth under hypoxic conditions. We further show that activation of EPA6 transcription depends on the Flo8 and Mss11 transcription factors and does not require the classical weak acid transcription factors War1 or Msn2/Msn4. We conclude that exposure of C. glabrata to commonly used preservatives can alter expression of virulence-related genes. PMID:19426114

Antifungal Properties of Cationic Phenylene Ethynylenes and Their Impact on β-Glucan Exposure.

PubMed

Pappas, Harry C; Sylejmani, Rina; Graus, Matthew S; Donabedian, Patrick L; Whitten, David G; Neumann, Aaron K

2016-08-01

Candida species are the cause of many bloodstream infections through contamination of indwelling medical devices. These infections account for a 40% mortality rate, posing a significant risk to immunocompromised patients. Traditional treatments against Candida infections include amphotericin B and various azole treatments. Unfortunately, these treatments are associated with high toxicity, and resistant strains have become more prevalent. As a new frontier, light-activated phenylene ethynylenes have shown promising biocidal activity against Gram-positive and -negative bacterial pathogens, as well as the environmental yeast Saccharomyces cerevisiae In this study, we monitored the viability of Candida species after treatment with a cationic conjugated polymer [poly(p-phenylene ethynylene); PPE] or oligomer ["end-only" oligo(p-phenylene ethynylene); EO-OPE] by flow cytometry in order to explore the antifungal properties of these compounds. The oligomer was found to disrupt Candida albicans yeast membrane integrity independent of light activation, while PPE is able to do so only in the presence of light, allowing for some control as to the manner in which cytotoxic effects are induced. The contrast in killing efficacy between the two compounds is likely related to their size difference and their intrinsic abilities to penetrate the fungal cell wall. Unlike EO-OPE-DABCO (where DABCO is quaternized diazabicyclo[2,2,2]octane), PPE-DABCO displayed a strong propensity to associate with soluble β-glucan, which is expected to inhibit its ability to access and perturb the inner cell membrane of Candida yeast. Furthermore, treatment with PPE-DABCO unmasked Candida albicans β-glucan and increased phagocytosis by Dectin-1-expressing HEK-293 cells. In summary, cationic phenylene ethynylenes show promising biocidal activity against pathogenic Candida yeast cells while also exhibiting immunostimulatory effects. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Antifungal Properties of Cationic Phenylene Ethynylenes and Their Impact on β-Glucan Exposure

PubMed Central

Pappas, Harry C.; Sylejmani, Rina; Graus, Matthew S.; Donabedian, Patrick L.; Whitten, David G.

2016-01-01

Candida species are the cause of many bloodstream infections through contamination of indwelling medical devices. These infections account for a 40% mortality rate, posing a significant risk to immunocompromised patients. Traditional treatments against Candida infections include amphotericin B and various azole treatments. Unfortunately, these treatments are associated with high toxicity, and resistant strains have become more prevalent. As a new frontier, light-activated phenylene ethynylenes have shown promising biocidal activity against Gram-positive and -negative bacterial pathogens, as well as the environmental yeast Saccharomyces cerevisiae. In this study, we monitored the viability of Candida species after treatment with a cationic conjugated polymer [poly(p-phenylene ethynylene); PPE] or oligomer [“end-only” oligo(p-phenylene ethynylene); EO-OPE] by flow cytometry in order to explore the antifungal properties of these compounds. The oligomer was found to disrupt Candida albicans yeast membrane integrity independent of light activation, while PPE is able to do so only in the presence of light, allowing for some control as to the manner in which cytotoxic effects are induced. The contrast in killing efficacy between the two compounds is likely related to their size difference and their intrinsic abilities to penetrate the fungal cell wall. Unlike EO-OPE-DABCO (where DABCO is quaternized diazabicyclo[2,2,2]octane), PPE-DABCO displayed a strong propensity to associate with soluble β-glucan, which is expected to inhibit its ability to access and perturb the inner cell membrane of Candida yeast. Furthermore, treatment with PPE-DABCO unmasked Candida albicans β-glucan and increased phagocytosis by Dectin-1-expressing HEK-293 cells. In summary, cationic phenylene ethynylenes show promising biocidal activity against pathogenic Candida yeast cells while also exhibiting immunostimulatory effects. PMID:27161628

Investigating the antifungal activity and mechanism(s) of geraniol against Candida albicans strains.

PubMed

Leite, Maria Clerya Alvino; de Brito Bezerra, André Parente; de Sousa, Janiere Pereira; de Oliveira Lima, Edeltrudes

2015-04-01

Candida albicans can be a yeast that is a commensal on the human body but can cause opportunistic or pathogenic infections. Candida infections may create serious health problems and as a result has initiated a search for new drugs with an antifungal action. Geraniol is an acyclic monoterpene alcohol with known pharmacological properties, including antimicrobial activity. The aim of this work was to evaluate the antifungal activity and mechanism(s) of geraniol against C. albicans strains. The minimum inhibitory concentration (MIC) was determined through broth microdilution techniques. We investigated possible geraniol activity on the fungal cell wall (sorbitol protect effect), cell membrane (geraniol to ergosterol binding), the time-kill curve, and its biological activity on the yeast's morphology. Amphotericin B was used as control, and all tests were performed in duplicate. The MIC of geraniol was 16 μg/ml (for 90% of isolates) but its probable mechanism of action did not involve the cell wall and ergosterol binding. In the morphological interference assay, we observed that the product inhibited pseudohyphae and chlamydoconidia formation. Time-dependent kill curve assay demonstrated that the fungicidal activity for MIC × 2 started at 2 h for the ATCC 76485 strain, and at 4 h for the LM-70 strain. Geraniol showed in vitro antifungal potential against strains of C. albicans but did not involve action on the cell wall or ergosterol. This study contributes to the development of new antifungal drugs, especially against Candida spp. © The Author 2014. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Hyperspectral fluorescence microscopy detects autofluorescent factors that can be exploited as a diagnostic method for Candida species differentiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Graus, Matthew S.; Neumann, Aaron K.; Timlin, Jerilyn A.

Fungi in the Candida genus are the most common fungal pathogens. They not only cause high morbidity and mortality but can also cost billions of dollars in healthcare. To alleviate this burden, early and accurate identification of Candida species is necessary. However, standard identification procedures can take days and have a large false negative error. The method described in this study takes advantage of hyperspectral confocal fluorescence microscopy, which enables the capability to quickly and accurately identify and characterize the unique autofluorescence spectra from different Candida species with up to 84% accuracy when grown in conditions that closely mimic physiologicalmore » conditions.« less

Hyperspectral fluorescence microscopy detects autofluorescent factors that can be exploited as a diagnostic method for Candida species differentiation

DOE PAGES

Graus, Matthew S.; Neumann, Aaron K.; Timlin, Jerilyn A.

2017-01-05

Fungi in the Candida genus are the most common fungal pathogens. They not only cause high morbidity and mortality but can also cost billions of dollars in healthcare. To alleviate this burden, early and accurate identification of Candida species is necessary. However, standard identification procedures can take days and have a large false negative error. The method described in this study takes advantage of hyperspectral confocal fluorescence microscopy, which enables the capability to quickly and accurately identify and characterize the unique autofluorescence spectra from different Candida species with up to 84% accuracy when grown in conditions that closely mimic physiologicalmore » conditions.« less

Aberrant Synthesis of Indole-3-Acetic Acid in Saccharomyces cerevisiae Triggers Morphogenic Transition, a Virulence Trait of Pathogenic Fungi

PubMed Central

Rao, Reeta Prusty; Hunter, Ally; Kashpur, Olga; Normanly, Jennifer

2010-01-01

Many plant-associated microbes synthesize the auxin indole-3-acetic acid (IAA), and several IAA biosynthetic pathways have been identified in microbes and plants. Saccharomyces cerevisiae has previously been shown to respond to IAA by inducing pseudohyphal growth. We observed that IAA also induced hyphal growth in the human pathogen Candida albicans and thus may function as a secondary metabolite signal that regulates virulence traits such as hyphal transition in pathogenic fungi. Aldehyde dehydrogenase (Ald) is required for IAA synthesis from a tryptophan (Trp) precursor in Ustilago maydis. Mutant S. cerevisiae with deletions in two ALD genes are unable to convert radiolabeled Trp to IAA, yet produce IAA in the absence of exogenous Trp and at levels higher than wild type. These data suggest that yeast may have multiple pathways for IAA synthesis, one of which is not dependent on Trp. PMID:20233857

Facing the challenges of multiscale modelling of bacterial and fungal pathogen–host interactions

PubMed Central

Schleicher, Jana; Conrad, Theresia; Gustafsson, Mika; Cedersund, Gunnar; Guthke, Reinhard

2017-01-01

Abstract Recent and rapidly evolving progress on high-throughput measurement techniques and computational performance has led to the emergence of new disciplines, such as systems medicine and translational systems biology. At the core of these disciplines lies the desire to produce multiscale models: mathematical models that integrate multiple scales of biological organization, ranging from molecular, cellular and tissue models to organ, whole-organism and population scale models. Using such models, hypotheses can systematically be tested. In this review, we present state-of-the-art multiscale modelling of bacterial and fungal infections, considering both the pathogen and host as well as their interaction. Multiscale modelling of the interactions of bacteria, especially Mycobacterium tuberculosis, with the human host is quite advanced. In contrast, models for fungal infections are still in their infancy, in particular regarding infections with the most important human pathogenic fungi, Candida albicans and Aspergillus fumigatus. We reflect on the current availability of computational approaches for multiscale modelling of host–pathogen interactions and point out current challenges. Finally, we provide an outlook for future requirements of multiscale modelling. PMID:26857943

Molecular identification and antifungal susceptibility profile of Candida species isolated from patients with vulvovaginitis in Tehran, Iran.

PubMed

Sharifynia, Somayeh; Falahati, Mehraban; Akhlaghi, Lame; Foroumadi, Alireza; Fateh, Roohollah

2017-01-01

Rapid and accurate identification and evaluation of antifungal susceptibility pattern of Candida isolates are crucial to determine suitable antifungal drugs for the treatment of patients with vulvovaginitis candidiasis. Vaginal samples were collected from 150 women with suspicious vaginal candidiasis, and then cultured on Sabouraoud's Dextrose Agar with chloramphenicol to isolate Candida species. After identification of Candida isolates using polymerase chain reaction-restriction fragment length polymorphism technique, antifungal susceptibility testing of four azolic antifungal drugs was carried out using broth microdilution method according to the CLSI M27-A3. Candida species were isolated from eighty suspected patients (61.79%). The most common pathogen was Candida albicans (63.75%). Resistance to fluconazole and ketoconazole was observed in 27.5% and 23.75% of Candida isolates, respectively, and only 2% of Candida isolates were resistant to miconazole. Interestingly, resistance to fluconazole in C. albicans was more than other Candida species. The results indicated that therapy should be selected according to the antifungal susceptibility tests for the prevention of treatment failure and miconazole therapy can be considered as the best therapeutic choice in the management of vulvovaginitis.

Molecular identification and antifungal susceptibility profile of Candida species isolated from patients with vulvovaginitis in Tehran, Iran

PubMed Central

Sharifynia, Somayeh; Falahati, Mehraban; Akhlaghi, Lame; Foroumadi, Alireza; Fateh, Roohollah

2017-01-01

Background: Rapid and accurate identification and evaluation of antifungal susceptibility pattern of Candida isolates are crucial to determine suitable antifungal drugs for the treatment of patients with vulvovaginitis candidiasis. Materials and Methods: Vaginal samples were collected from 150 women with suspicious vaginal candidiasis, and then cultured on Sabouraoud's Dextrose Agar with chloramphenicol to isolate Candida species. After identification of Candida isolates using polymerase chain reaction-restriction fragment length polymorphism technique, antifungal susceptibility testing of four azolic antifungal drugs was carried out using broth microdilution method according to the CLSI M27-A3. Results: Candida species were isolated from eighty suspected patients (61.79%). The most common pathogen was Candida albicans (63.75%). Resistance to fluconazole and ketoconazole was observed in 27.5% and 23.75% of Candida isolates, respectively, and only 2% of Candida isolates were resistant to miconazole. Interestingly, resistance to fluconazole in C. albicans was more than other Candida species. Conclusion: The results indicated that therapy should be selected according to the antifungal susceptibility tests for the prevention of treatment failure and miconazole therapy can be considered as the best therapeutic choice in the management of vulvovaginitis. PMID:29387119

Urinary tract infections and Candida albicans.

PubMed

Behzadi, Payam; Behzadi, Elham; Ranjbar, Reza

2015-01-01

Urinary tract candidiasis is known as the most frequent nosocomial fungal infection worldwide. Candida albicans is the most common cause of nosocomial fungal urinary tract infections; however, a rapid change in the distribution of Candida species is undergoing. Simultaneously, the increase of urinary tract candidiasis has led to the appearance of antifungal resistant Candida species. In this review, we have an in depth look into Candida albicans uropathogenesis and distribution of the three most frequent Candida species contributing to urinary tract candidiasis in different countries around the world. For writing this review, Google Scholar -a scholarly search engine- (http://scholar.google.com/) and PubMed database (http://www.ncbi.nlm.nih.gov/pubmed/) were used. The most recently published original articles and reviews of literature relating to the first three Candida species causing urinary tract infections in different countries and the pathogenicity of Candida albicans were selected and studied. Although some studies show rapid changes in the uropathogenesis of Candida species causing urinary tract infections in some countries, Candida albicans is still the most important cause of candidal urinary tract infections. Despite the ranking of Candida albicans as the dominant species for urinary tract candidiasis, specific changes have occurred in some countries. At this time, it is important to continue the surveillance related to Candida species causing urinary tract infections to prevent, control and treat urinary tract candidiasis in future.

Evaluation of a rapid, quantitative real-time PCR method for enumeration of pathogenic Candida cells in water

USGS Publications Warehouse

Brinkman, Nichole E.; Haugland, Richard A.; Wymer, Larry J.; Byappanahalli, Muruleedhara N.; Whitman, Richard L.; Vesper, Stephen J.

2003-01-01

Quantitative PCR (QPCR) technology, incorporating fluorigenic 5′ nuclease (TaqMan) chemistry, was utilized for the specific detection and quantification of six pathogenic species of Candida (C. albicans, C. tropicalis, C. krusei, C. parapsilosis, C. glabrata and C. lusitaniae) in water. Known numbers of target cells were added to distilled and tap water samples, filtered, and disrupted directly on the membranes for recovery of DNA for QPCR analysis. The assay's sensitivities were between one and three cells per filter. The accuracy of the cell estimates was between 50 and 200% of their true value (95% confidence level). In similar tests with surface water samples, the presence of PCR inhibitory compounds necessitated further purification and/or dilution of the DNA extracts, with resultant reductions in sensitivity but generally not in quantitative accuracy. Analyses of a series of freshwater samples collected from a recreational beach showed positive correlations between the QPCR results and colony counts of the corresponding target species. Positive correlations were also seen between the cell quantities of the target Candida species detected in these analyses and colony counts of Enterococcus organisms. With a combined sample processing and analysis time of less than 4 h, this method shows great promise as a tool for rapidly assessing potential exposures to waterborne pathogenic Candida species from drinking and recreational waters and may have applications in the detection of fecal pollution.

Photodynamic therapy with water-soluble phtalocyanines against bacterial biofilms in teeth root canals

NASA Astrophysics Data System (ADS)

Gergova, Raina; Georgieva, Tzvetelina; Angelov, Ivan; Mantareva, Vanya; Valkanov, Serjoga; Mitov, Ivan; Dimitrov, Slavcho

2012-06-01

The study presents the PDT with metal phthalocyanines on biofilms grown in root canals of ten representatives of the Gram-positive and the Gram-negative bacterial species and a fungus Candida albicans which cause aqute teeth infections in root canals.. The extracted human single-root teeth infected for 48 h with microorganisms in conditions to form biofilms of the above pathogens were PDT treated. The stage of biofilm formation and PDT effect of the samples of the teeth were determined by the scaning electron microscopy and with standard microbial tests. The PDT treating procedure included 10 min incubation with the respected phthalocyanine and irradiated with 660 nm Diode laser for 10 min. The most strongly antibacterial activity was achieved with zinc(II) phthalocyanine (ZnPc) against Enterococcus faecalis, Staphylococcus aureus and Moraxella catarrhalis. The other Gram-negative bacteria and Candida albicans were 10-100 times more resistant than the Gram-positive species. The Gram-negative Moraxella catarrhalis and Acinetobacter baumannii were more sensitive than the enterobacteria, but eradication of Pseudomonas aeruginosa in biofilm was insignificant. The influence of the stage of biofilm formation and the initial conditions (bacterial density, photosensitizer concentration and energy fluence of radiation) to the obtained level of inactivation of biofilms was investigated. The PDT with ZnPc photosensitizers show a powerful antimicrobial activity against the most frequent pathogens in endodontic infections and this method for inactivation of pathogens may be used with sucsses for treatment of the bacterial biofilms in the root canals.

Posaconazole exhibits in vitro and in vivo synergistic antifungal activity with caspofungin or FK506 against Candida albicans.

PubMed

Chen, Ying-Lien; Lehman, Virginia N; Averette, Anna F; Perfect, John R; Heitman, Joseph

2013-01-01

The object of this study was to test whether posaconazole, a broad-spectrum antifungal agent inhibiting ergosterol biosynthesis, exhibits synergy with the β-1,3 glucan synthase inhibitor caspofungin or the calcineurin inhibitor FK506 against the human fungal pathogen Candida albicans. Although current drug treatments for Candida infection are often efficacious, the available antifungal armamentarium may not be keeping pace with the increasing incidence of drug resistant strains. The development of drug combinations or novel antifungal drugs to address emerging drug resistance is therefore of general importance. Combination drug therapies are employed to treat patients with HIV, cancer, or tuberculosis, and has considerable promise in the treatment of fungal infections like cryptococcal meningitis and C. albicans infections. Our studies reported here demonstrate that posaconazole exhibits in vitro synergy with caspofungin or FK506 against drug susceptible or resistant C. albicans strains. Furthermore, these combinations also show in vivo synergy against C. albicans strain SC5314 and its derived echinocandin-resistant mutants, which harbor an S645Y mutation in the CaFks1 β-1,3 glucan synthase drug target, suggesting potential therapeutic applicability for these combinations in the future.

The Role of Dectin-2 for Host Defense Against Disseminated Candidiasis.

PubMed

Ifrim, Daniela C; Quintin, Jessica; Courjol, Flavie; Verschueren, Ineke; van Krieken, J Han; Koentgen, Frank; Fradin, Chantal; Gow, Neil A R; Joosten, Leo A B; van der Meer, Jos W M; van de Veerdonk, Frank; Netea, Mihai G

2016-04-01

Despite the fact that Candida albicans is an important human fungal pathogen and Dectin-2 is a major pattern recognition receptor for fungi, our knowledge regarding the role of Dectin-2 for the host defense against disseminated candidiasis is limited. Dectin-2 deficient (Dectin-2(-/-)) mice were more susceptible to systemic candidiasis, and the susceptibility was mirrored by an elevated fungal load in the kidneys that correlated with the presence of large inflammatory foci. Phagocytosis of Candida by the macrophages lacking the Dectin-2 receptor was moderately decreased, while production of most of the macrophage-derived cytokines from Dectin-2(-/-) mice with systemic candidiasis was decreased. No striking differences among several Candida mutants defective in mannans could be detected between naïve wild-type and Dectin-2(-/-) mice, apart from the β-mannan-deficient bmt1Δ/bmt2Δ/bmt5Δ triple mutant, suggesting that β-mannan may partially mask α-mannan detection, which is the major fungal structure recognized by Dectin-2. Deciphering the mechanisms responsible for host defense against the majority of C. albicans strains represents an important step in understanding the pathophysiology of systemic candidiasis, which might lead to the development of novel immunotherapeutic strategies.

The Three Clades of the Telomere-Associated TLO Gene Family of Candida albicans Have Different Splicing, Localization, and Expression Features

PubMed Central

Anderson, Matthew Z.; Baller, Joshua A.; Dulmage, Keely; Wigen, Lauren

2012-01-01

Candida albicans grows within a wide range of host niches, and this adaptability enhances its success as a commensal and as a pathogen. The telomere-associated TLO gene family underwent a recent expansion from one or two copies in other CUG clade members to 14 expressed copies in C. albicans. This correlates with increased virulence and clinical prevalence relative to those of other Candida clade species. The 14 expressed TLO gene family members have a conserved Med2 domain at the N terminus, suggesting a role in general transcription. The C-terminal half is more divergent, distinguishing three clades: clade α and clade β have no introns and encode proteins that localize primarily to the nucleus; clade γ sometimes undergoes splicing, and the gene products localize within the mitochondria as well as the nuclei. Additionally, TLOα genes are generally expressed at much higher levels than are TLOγ genes. We propose that expansion of the TLO gene family and the predicted role of Tlo proteins in transcription regulation provide C. albicans with the ability to adapt rapidly to the broad range of different environmental niches within the human host. PMID:22923044

Mitochondrial Telomeres as Molecular Markers for Identification of the Opportunistic Yeast Pathogen Candida parapsilosis

PubMed Central

Nosek, Jozef; Tomáška, L'ubomír; Ryčovská, Adriana; Fukuhara, Hiroshi

2002-01-01

Recent studies have demonstrated that a large number of organisms carry linear mitochondrial DNA molecules possessing specialized telomeric structures at their ends. Based on this specific structural feature of linear mitochondrial genomes, we have developed an approach for identification of the opportunistic yeast pathogen Candida parapsilosis. The strategy for identification of C. parapsilosis strains is based on PCR amplification of specific DNA sequences derived from the mitochondrial telomere region. This assay is complemented by immunodetection of a protein component of mitochondrial telomeres. The results demonstrate that mitochondrial telomeres represent specific molecular markers with potential applications in yeast diagnostics and taxonomy. PMID:11923346

The Role of PCR in the Diagnosis of Candida Vulvovaginitis-a New Gold Standard?

PubMed

Sobel, J D; Akins, Robert A

2015-06-01

PCR is recognized as a reliable technique for detection of all types of microorganisms. Being highly objective and reproducible also sensitive and specific, PCR is now widely used for sexually transmitted infection (STI) diagnosis. Potential, however, exists for detecting non-pathogens, and not identifying a pathogenic state decreases specificity or clinical significance. PCR Candida tests of vaginal specimens are now widely available and frequently used offering a modest to moderate increase in sensitivity and are likely to replace traditional culture and DNA homology testing. Nevertheless, there remain considerable gaps in our knowledge regarding the usefulness and applications of these expensive tests.

Development of a chip-based multiplexed immunoassay using liposomal nanovesicles and its application in the detection of pathogens causing female lower genital tract infections.

PubMed

Su, Wen-Hsiang; Ho, Tien-Yu; Tsou, Tsung-Shan; Lee, Wen-Ling; Wang, Kuan-Chin; Yu, Yuan-Yi; Chen, Tien-Jui; Tan, Chia-Hsuan; Kuo, Cheng-Deng; Chen, Chien-Sheng; Wang, Peng-Hui

2013-03-01

Cervicovaginitis is a highly prevalent disease that is a burden on healthcare globally. Immediate and adequate treatment can eradicate the infection and block subsequent complications. The feasibility of achip-based multiplexed immunoassay using liposomal nanovesicles was tested. A multiplexed immunoassay chip containing five antibodies for five pathogens (Chlamydia trachomatis, Escherichia coli, Neisseria gonorrhoeae, Streptococcus agalactiae, and Candida albicans) was established and tested. Four patients with spiking of candidiasis were enrolled. The difference between positive and negative readings was evaluated using the paired Student t test. The detection threshold of Candida in this microarray was 100,000 CFU/mL in a vaginal sample, and the time required for the whole procedure was 3 hours. The testing of the four patients showed 100% for both sensitivity and specificity. This microarray chip was a rapid, easy, inexpensive and sensitive tool for detecting female lower genital tract Candida infection in a one-time vaginal sampling process, although the data on the four other pathogens were still unavailable. A larger population study is encouraged to test the validity of this multiplexed immunoassay chip. Copyright © 2013. Published by Elsevier B.V.

Thionin-like peptide from Capsicum annuum fruits: mechanism of action and synergism with fluconazole against Candida species.

PubMed

Taveira, Gabriel B; Carvalho, André O; Rodrigues, Rosana; Trindade, Fernanda G; Da Cunha, Maura; Gomes, Valdirene M

2016-01-27

Thionins are a family of plant antimicrobial peptides (AMPs), which participate in plant defense system against pathogens. Here we describe some aspects of the CaThi thionin-like action mechanism, previously isolated from Capsicum annuum fruits. Thionin-like peptide was submitted to antimicrobial activity assays against Candida species for IC50 determination and synergism with fluconazole evaluation. Viability and plasma membrane permeabilization assays, induction of intracellular ROS production analysis and CaThi localization in yeast cells were also investigated. CaThi had strong antimicrobial activity against six tested pathogenic Candida species, with IC50 ranging from 10 to 40 μg.mL(-1). CaThi antimicrobial activity on Candida species was candidacidal. Moreover, CaThi caused plasma membrane permeabilization in all yeasts tested and induces oxidative stresses only in Candida tropicalis. CaThi was intracellularly localized in C. albicans and C. tropicalis, however localized in nuclei in C. tropicalis, suggesting a possible nuclear target. CaThi performed synergistically with fluconazole inhibiting all tested yeasts, reaching 100% inhibition in C. parapsilosis. The inhibiting concentrations for the synergic pair ranged from 1.3 to 4.0 times below CaThi IC50 and from zero to 2.0 times below fluconazole IC50. The results reported herein may ultimately contribute to future efforts aiming to employ this plant-derived AMP as a new therapeutic substance against yeasts.

The effect of Zuccagnia punctata, an Argentine medicinal plant, on virulence factors from candida species.

PubMed

Gabriela, Nuño; Rosa, Alberto María; Catiana, Zampini Iris; Soledad, Cuello; Mabel, Ordoñez Roxana; Esteban, Sayago Jorge; Veronica, Baroni; Daniel, Wunderlin; Ines, Isla María

2014-07-01

Zuccagnia punctata Cav. has been used as a traditional medicine in Argentina for the treatment of bacterial and fungal infections. In this study, we evaluated the ability of Z. punctata extract (ZpE) and compounds isolated from it to inhibit the growth and virulence factors of Candida species. ZpE showed inhibitory activity against planktonic cells of all assayed Candida species with MIC values of 400 microg/mL and with MFC values between 400 and 1,200 microg/mL. The principal identified compounds by HPLC-MS/MS and UV-VIS were chalcones (2',4'-dihydroxy-3'-methoxychalcone, 2',4'- dihydroxychalcone), flavones (galangin, 3,7-dihydroxyflavone and chrysin) and flavanones (naringenin, 7-hydroxyflavanone and pinocembrine). These compounds were more effective as inhibitors than the extracts upon biofilm formation as well as on preformed Candida biofilm and yeast germ tube formation. Furthermore, ZpE and chalcones are able to inhibit exoenzymes, which are responsible for the invasion mechanisms of the pathogens. All these effects could moderate colonization, thereby suppressing the pathogen invasive potential. Our results indicate that ZpE and chalcones could be used in antifungal therapy.

Sequence and Analysis of the Genome of the Pathogenic Yeast Candida orthopsilosis

PubMed Central

Riccombeni, Alessandro; Vidanes, Genevieve; Proux-Wéra, Estelle; Wolfe, Kenneth H.; Butler, Geraldine

2012-01-01

Candida orthopsilosis is closely related to the fungal pathogen Candida parapsilosis. However, whereas C. parapsilosis is a major cause of disease in immunosuppressed individuals and in premature neonates, C. orthopsilosis is more rarely associated with infection. We sequenced the C. orthopsilosis genome to facilitate the identification of genes associated with virulence. Here, we report the de novo assembly and annotation of the genome of a Type 2 isolate of C. orthopsilosis. The sequence was obtained by combining data from next generation sequencing (454 Life Sciences and Illumina) with paired-end Sanger reads from a fosmid library. The final assembly contains 12.6 Mb on 8 chromosomes. The genome was annotated using an automated pipeline based on comparative analysis of genomes of Candida species, together with manual identification of introns. We identified 5700 protein-coding genes in C. orthopsilosis, of which 5570 have an ortholog in C. parapsilosis. The time of divergence between C. orthopsilosis and C. parapsilosis is estimated to be twice as great as that between Candida albicans and Candida dubliniensis. There has been an expansion of the Hyr/Iff family of cell wall genes and the JEN family of monocarboxylic transporters in C. parapsilosis relative to C. orthopsilosis. We identified one gene from a Maltose/Galactoside O-acetyltransferase family that originated by horizontal gene transfer from a bacterium to the common ancestor of C. orthopsilosis and C. parapsilosis. We report that TFB3, a component of the general transcription factor TFIIH, undergoes alternative splicing by intron retention in multiple Candida species. We also show that an intein in the vacuolar ATPase gene VMA1 is present in C. orthopsilosis but not C. parapsilosis, and has a patchy distribution in Candida species. Our results suggest that the difference in virulence between C. parapsilosis and C. orthopsilosis may be associated with expansion of gene families. PMID:22563396

ER stress response mechanisms in the pathogenic yeast Candida glabrata and their roles in virulence

PubMed Central

Miyazaki, Taiga; Kohno, Shigeru

2014-01-01

The maintenance of endoplasmic reticulum (ER) homeostasis is critical for numerous aspects of cell physiology. Eukaryotic cells respond to the accumulation of misfolded proteins in the ER (ER stress) by activating the unfolded protein response (UPR), an intracellular signaling pathway that adjusts the folding capacity of the ER. Recent studies of several pathogenic fungi have revealed that the UPR is important for antifungal resistance and virulence; therefore, the pathway has attracted much attention as a potential therapeutic target. While the UPR is highly conserved among eukaryotes, our group recently discovered that the pathogenic yeast Candida glabrata lacks the typical fungal UPR, but possesses alternative mechanisms to cope with ER stress. This review summarizes how C. glabrata responds to ER stress and discusses the impacts of ER quality control systems on antifungal resistance and virulence. PMID:24335436

ERG2 and ERG24 Are Required for Normal Vacuolar Physiology as Well as Candida albicans Pathogenicity in a Murine Model of Disseminated but Not Vaginal Candidiasis

PubMed Central

Luna-Tapia, Arturo; Peters, Brian M.; Eberle, Karen E.; Kerns, Morgan E.; Foster, Timothy P.; Marrero, Luis; Noverr, Mairi C.; Fidel, Paul L.

2015-01-01

Several important classes of antifungal agents, including the azoles, act by blocking ergosterol biosynthesis. It was recently reported that the azoles cause massive disruption of the fungal vacuole in the prevalent human pathogen Candida albicans. This is significant because normal vacuolar function is required to support C. albicans pathogenicity. This study examined the impact of the morpholine antifungals, which inhibit later steps of ergosterol biosynthesis, on C. albicans vacuolar integrity. It was found that overexpression of either the ERG2 or ERG24 gene, encoding C-8 sterol isomerase or C-14 sterol reductase, respectively, suppressed C. albicans sensitivity to the morpholines. In addition, both erg2Δ/Δ and erg24Δ/Δ mutants were hypersensitive to the morpholines. These data are consistent with the antifungal activity of the morpholines depending upon the simultaneous inhibition of both Erg2p and Erg24p. The vacuoles within both erg2Δ/Δ and erg24Δ/Δ C. albicans strains exhibited an aberrant morphology and accumulated large quantities of the weak base quinacrine, indicating enhanced vacuolar acidification compared with that of control strains. Both erg mutants exhibited significant defects in polarized hyphal growth and were avirulent in a mouse model of disseminated candidiasis. Surprisingly, in a mouse model of vaginal candidiasis, both mutants colonized mice at high levels and induced a pathogenic response similar to that with the controls. Thus, while targeting Erg2p or Erg24p alone could provide a potentially efficacious therapy for disseminated candidiasis, it may not be an effective strategy to treat vaginal infections. The potential value of drugs targeting these enzymes as adjunctive therapies is discussed. PMID:26231054

ERG2 and ERG24 Are Required for Normal Vacuolar Physiology as Well as Candida albicans Pathogenicity in a Murine Model of Disseminated but Not Vaginal Candidiasis.

PubMed

Luna-Tapia, Arturo; Peters, Brian M; Eberle, Karen E; Kerns, Morgan E; Foster, Timothy P; Marrero, Luis; Noverr, Mairi C; Fidel, Paul L; Palmer, Glen E

2015-10-01

Several important classes of antifungal agents, including the azoles, act by blocking ergosterol biosynthesis. It was recently reported that the azoles cause massive disruption of the fungal vacuole in the prevalent human pathogen Candida albicans. This is significant because normal vacuolar function is required to support C. albicans pathogenicity. This study examined the impact of the morpholine antifungals, which inhibit later steps of ergosterol biosynthesis, on C. albicans vacuolar integrity. It was found that overexpression of either the ERG2 or ERG24 gene, encoding C-8 sterol isomerase or C-14 sterol reductase, respectively, suppressed C. albicans sensitivity to the morpholines. In addition, both erg2Δ/Δ and erg24Δ/Δ mutants were hypersensitive to the morpholines. These data are consistent with the antifungal activity of the morpholines depending upon the simultaneous inhibition of both Erg2p and Erg24p. The vacuoles within both erg2Δ/Δ and erg24Δ/Δ C. albicans strains exhibited an aberrant morphology and accumulated large quantities of the weak base quinacrine, indicating enhanced vacuolar acidification compared with that of control strains. Both erg mutants exhibited significant defects in polarized hyphal growth and were avirulent in a mouse model of disseminated candidiasis. Surprisingly, in a mouse model of vaginal candidiasis, both mutants colonized mice at high levels and induced a pathogenic response similar to that with the controls. Thus, while targeting Erg2p or Erg24p alone could provide a potentially efficacious therapy for disseminated candidiasis, it may not be an effective strategy to treat vaginal infections. The potential value of drugs targeting these enzymes as adjunctive therapies is discussed. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Tight Control of Trehalose Content Is Required for Efficient Heat-induced Cell Elongation in Candida albicans*

PubMed Central

Serneels, Joke; Tournu, Hélène; Van Dijck, Patrick

2012-01-01

The ability to form hyphae in the human pathogenic fungus Candida albicans is a prerequisite for virulence. It contributes to tissue infection, biofilm formation, as well as escape from phagocytes. Cell elongation triggered by human body temperature involves the essential heat shock protein Hsp90, which negatively governs a filamentation program dependent upon the Ras-protein kinase A (PKA) pathway. Tight regulation of Hsp90 function is required to ensure fast appropriate response and maintenance of a wide range of regulatory and signaling proteins. Client protein activation by Hsp90 relies on a conformational change of the chaperone, whose ATPase activity is competitively inhibited by geldanamycin. We demonstrate a novel regulatory mechanism of heat- and Hsp90-dependent induced morphogenesis, whereby the nonreducing disaccharide trehalose acts as a negative regulator of Hsp90 release. By means of a mutant strain deleted for Gpr1, the G protein-coupled receptor upstream of PKA, we demonstrate that elevated trehalose content in that strain, resulting from misregulation of enzymatic activities involved in trehalose metabolism, disrupts the filamentation program in response to heat. Addition of geldanamycin does not result in hyphal extensions at 30 °C in the gpr1Δ/gpr1Δ mutant as it does in wild type cells. In addition, validamycin, a specific inhibitor of trehalase, the trehalose-degrading enzyme, inhibits cell elongation in response to heat and geldanamycin. These results place Gpr1 as a regulator of trehalose metabolism in C. albicans and illustrate that trehalose modulates Hsp90-dependent activation of client proteins and signaling pathways leading to filamentation in the human fungal pathogen. PMID:22952228

Micafungin Enhances the Human Macrophage Response to Candida albicans through β-Glucan Exposure.

PubMed

Guirao-Abad, José Pedro; Sánchez-Fresneda, Ruth; Machado, Francisco; Argüelles, Juan Carlos; Martínez-Esparza, María

2018-05-01

Micafungin belongs to the antifungal family of echinocandins, which act as noncompetitive inhibitors of the fungal cell wall β-1,3-d-glucan synthase. Since Candida albicans is the most prevalent pathogenic fungus in humans, we study the involvement of micafungin in the modulation of the inflammatory response developed by human tissue macrophages against C. albicans The MIC for micafungin was 0.016 μg/ml on the C. albicans SC5314 standard strain. Micafungin induced a drastic reduction in the number of exponential SC5314 viable cells, with the fungicidal effect being dependent on the cellular metabolic activity. Notably, micafungin also caused a structural remodelling of the cell wall, leading to exposure of the β-glucan and chitin content on the external surface. At the higher doses used (0.05 μg/ml), the antifungal also induced the blowing up of budding yeasts. In addition, preincubation with micafungin before exposure to human tissue macrophages enhanced the secretion of tumor necrosis factor alpha (TNF-α), interleukin-17A (IL-17A), and IL-10 cytokines. Our results strongly suggest that in C. albicans treatment with micafungin, in addition to having the expected toxic antifungal effect, it potentiates the immune response, improving the interaction and activation of human macrophages, probably through the unmasking of β-glucans on the cell wall surface. Copyright © 2018 American Society for Microbiology.

The synthesis, regulation, and functions of sterols in Candida albicans: Well-known but still lots to learn.

PubMed

Lv, Quan-Zhen; Yan, Lan; Jiang, Yuan-Ying

2016-08-17

Sterols are the basal components of the membranes of the fungal pathogen Candida albicans, and these membranes determine the susceptibility of C. albicans cells to a variety of stresses, such as ionic, osmotic and oxidative pressures, and treatment with antifungal drugs. The common antifungal azoles in clinical use are targeted to the biosynthesis of ergosterol. In the past years, the synthesis, storage and metabolism of ergosterol in Saccharomyces cerevisiae has been characterized in some detail; however, these processes has not been as well investigated in the human opportunistic pathogen C. albicans. In this review, we summarize the genes involved in ergosterol synthesis and regulation in C. albicans. As well, genes in S. cerevisiae implicated in ergosterol storage and conversions with other lipids are noted, as these provide us clues and directions for the study of the homologous genes in C. albicans. In this report we have particularly focused on the essential roles of ergosterol in the dynamic process of cell biology and its fundamental status in the biological membrane system that includes lipid rafts, lipid droplets, vacuoles and mitochondria. We believe that a thorough understanding of this classic and essential pathway will give us new ideas about drug resistance and morphological switching in C. albicans.

The synthesis, regulation, and functions of sterols in Candida albicans: Well-known but still lots to learn

PubMed Central

Lv, Quan-zhen; Yan, Lan; Jiang, Yuan-ying

2016-01-01

ABSTRACT Sterols are the basal components of the membranes of the fungal pathogen Candida albicans, and these membranes determine the susceptibility of C. albicans cells to a variety of stresses, such as ionic, osmotic and oxidative pressures, and treatment with antifungal drugs. The common antifungal azoles in clinical use are targeted to the biosynthesis of ergosterol. In the past years, the synthesis, storage and metabolism of ergosterol in Saccharomyces cerevisiae has been characterized in some detail; however, these processes has not been as well investigated in the human opportunistic pathogen C. albicans. In this review, we summarize the genes involved in ergosterol synthesis and regulation in C. albicans. As well, genes in S. cerevisiae implicated in ergosterol storage and conversions with other lipids are noted, as these provide us clues and directions for the study of the homologous genes in C. albicans. In this report we have particularly focused on the essential roles of ergosterol in the dynamic process of cell biology and its fundamental status in the biological membrane system that includes lipid rafts, lipid droplets, vacuoles and mitochondria. We believe that a thorough understanding of this classic and essential pathway will give us new ideas about drug resistance and morphological switching in C. albicans. PMID:27221657

Gymnemic Acids Inhibit Hyphal Growth and Virulence in Candida albicans

PubMed Central

Vediyappan, Govindsamy; Dumontet, Vincent; Pelissier, Franck; d’Enfert, Christophe

2013-01-01

Candida albicans is an opportunistic and polymorphic fungal pathogen that causes mucosal, disseminated and invasive infections in humans. Transition from the yeast form to the hyphal form is one of the key virulence factors in C. albicans contributing to macrophage evasion, tissue invasion and biofilm formation. Nontoxic small molecules that inhibit C. albicans yeast-to-hypha conversion and hyphal growth could represent a valuable source for understanding pathogenic fungal morphogenesis, identifying drug targets and serving as templates for the development of novel antifungal agents. Here, we have identified the triterpenoid saponin family of gymnemic acids (GAs) as inhibitor of C. albicans morphogenesis. GAs were isolated and purified from Gymnema sylvestre leaves, the Ayurvedic traditional medicinal plant used to treat diabetes. Purified GAs had no effect on the growth and viability of C. albicans yeast cells but inhibited its yeast-to-hypha conversion under several hypha-inducing conditions, including the presence of serum. Moreover, GAs promoted the conversion of C. albicans hyphae into yeast cells under hypha inducing conditions. They also inhibited conidial germination and hyphal growth of Aspergillus sp. Finally, GAs inhibited the formation of invasive hyphae from C. albicans-infected Caenorhabditis elegans worms and rescued them from killing by C. albicans. Hence, GAs could be useful for various antifungal applications due to their traditional use in herbal medicine. PMID:24040201

Elevated Chitin Content Reduces the Susceptibility of Candida Species to Caspofungin

PubMed Central

Walker, Louise A.; Gow, Neil A. R.

2013-01-01

The echinocandin antifungal drugs inhibit synthesis of the major fungal cell wall polysaccharide β(1,3)-glucan. Echinocandins have good efficacy against Candida albicans but reduced activity against other Candida species, in particular Candida parapsilosis and Candida guilliermondii. Treatment of Candida albicans with a sub-MIC level of caspofungin has been reported to cause a compensatory increase in chitin content and to select for sporadic echinocandin-resistant FKS1 point mutants that also have elevated cell wall chitin. Here we show that elevated chitin in response to caspofungin is a common response in various Candida species. Activation of chitin synthesis was observed in isolates of C. albicans, Candida tropicalis, C. parapsilosis, and C. guilliermondii and in some isolates of Candida krusei in response to caspofungin treatment. However, Candida glabrata isolates demonstrated no exposure-induced change in chitin content. Furthermore, isolates of C. albicans, C. krusei, C. parapsilosis, and C. guilliermondii which were stimulated to have higher chitin levels via activation of the calcineurin and protein kinase C (PKC) signaling pathways had reduced susceptibility to caspofungin. Isolates containing point mutations in the FKS1 gene generally had higher chitin levels and did not demonstrate a further compensatory increase in chitin content in response to caspofungin treatment. These results highlight the potential of increased chitin synthesis as a potential mechanism of tolerance to caspofungin for the major pathogenic Candida species. PMID:23089748

Detection of Candida species in pregnant Chinese women with a molecular beacon method.

PubMed

Zhai, Yanhong; Liu, Jing; Zhou, Li; Ji, Tongzhen; Meng, Lingxin; Gao, Yang; Liu, Ran; Wang, Xiao; Li, Lin; Lu, Binghuai; Cao, Zheng

2018-04-20

Candida pathogens are commonly found in women and can cause vulvovaginal candidiasis (VVC), whose infection rate is further increased during pregnancy. We aimed to study the Candida prevalence and strain distribution in pregnant Chinese women with a molecular beacon assay. From March 2016 to February 2017, a total of 993 pregnant women attending routine antenatal visits at the Beijing Obstetrics and Gynecology Hospital were enrolled. For Candida detection and identification, a unique molecular beacon assay was presented and compared with a traditional phenotypic method. Antifungal susceptibility was tested with the following agents: 5-flucytosine, amphotericin B, fluconazole, itraconazole and voriconazole. The prevalence of Candida was found to be 21.8 % when using the molecular method and 15.0 % when using the phenotypic method. The distribution of the Candida spp. was listed in order of decreasing prevalence: Candida albicans (79.8 %), Candida glabrata (13.5 %), Candida parapsilosis (3.7 %), Candida krusei (2.2 %) and Candida tropicalis (1.1 %). We found that 90.7 % of the Candida detection results were consistent between the molecular and the phenotypic methods. In the cases where the sequencing analyses for the Candida isolates resulted in inconsistent identification, the molecular method showed higher sensitivity than the phenotypic method (96.0 vs 64.6 %). C. albicans, C. glabrata and C. parapsilosis were essentially susceptible to all five antifungal agents tested, whereas C. tropicalis and C. krusei were susceptible to voriconazole and amphotericin B. By exhibiting good sensitivity and specificity, the molecular assay may offer a fast and accurate Candida screening platform for pregnant women.

Caspase-8 modulates Dectin-1 and CR3 driven IL-1β production in response to β-glucans and the fungal pathogen, Candida albicans1

PubMed Central

Ganesan, Sandhya; Rathinam, Vijay A. K.; Bossaller, Lukas; Army, Kelly; Kaiser, William J.; Mocarski, Edward S.; Dillon, Christopher P.; Green, Douglas R.; Mayadas, Tanya N.; Levitz, Stuart M.; Hise, Amy G.

2014-01-01

Inflammasomes are central mediators of host defense to a wide range of microbial pathogens. The NLRP3 inflammasome plays a key role in triggering caspase-1 dependent IL-1β maturation and resistance to fungal dissemination in Candida albicans infection. β-glucans are major components of fungal cell walls that trigger IL-1β secretion in both murine and human immune cells. In this study, we sought to determine the contribution of β-glucans to C. albicans-induced inflammasome responses in mouse dendritic cells. We show that the NLRP3-ASC-caspase-1 inflammasome is absolutely critical for IL-1β production in response to β-glucans. Interestingly, we also found that both Complement Receptor 3 (CR3/Mac-1) and dectin-1 play a crucial role in coordinating β-glucan-induced IL-1β processing as well as a cell death response. In addition to the essential role of caspase-1, we identify an important role for the pro-apoptotic protease caspase-8 in promoting β-glucan-induced cell death and NLRP3 inflammasome-dependent IL-1β maturation. A strong requirement for Complement Receptor 3 and caspase-8 was also found for NLRP3 dependent IL-1β production in response to heat killed Candida albicans. Together, these results define the importance of dectin-1, CR3 and caspase-8, in addition to the canonical NLRP3 inflammasome, in mediating β-glucan and C. albicans induced innate responses in dendritic cells. Collectively, these findings establish a novel link between β-glucan recognition receptors and the inflammatory proteases caspase-8 and caspase-1 in coordinating cytokine secretion and cell death in response to immunostimulatory fungal components. PMID:25063877

Lactate signalling regulates fungal β-glucan masking and immune evasion

PubMed Central

Ballou, Elizabeth R.; Avelar, Gabriela M.; Childers, Delma S.; Mackie, Joanna; Bain, Judith M.; Wagener, Jeanette; Kastora, Stavroula L.; Panea, Mirela D.; Hardison, Sarah E.; Walker, Louise A.; Erwig, Lars P.; Munro, Carol A.; Gow, Neil A.R.; Brown, Gordon D.; MacCallum, Donna M.; Brown, Alistair J.P.

2017-01-01

Summary Paragraph As they proliferate, fungi expose antigens at their cell surface that are potent stimulators of the innate immune response, and yet the commensal fungus Candida albicans is able to colonize immuno-competent individuals. We show that C. albicans may evade immune detection by presenting a moving immunological target. We report that the exposure of β-glucan, a key Pathogen Associated Molecular Pattern (PAMP) located at the cell surface of C. albicans and other pathogenic Candida species, is modulated in response to changes in carbon source. Exposure to lactate induces β-glucan masking in C. albicans via a signaling pathway that has recruited an evolutionarily conserved receptor (Gpr1) and transcriptional factor (Crz1) from other well-characterized pathways. In response to lactate, these regulators control the expression of cell wall related genes that contribute to β-glucan masking. This represents the first description of active PAMP masking by a Candida species, a process that reduces the visibility of the fungus to the immune system. PMID:27941860

Central Role of the Trehalose Biosynthesis Pathway in the Pathogenesis of Human Fungal Infections: Opportunities and Challenges for Therapeutic Development

PubMed Central

Thammahong, Arsa; Puttikamonkul, Srisombat; Perfect, John R.; Brennan, Richard G.

2017-01-01

SUMMARY Invasive fungal infections cause significant morbidity and mortality in part due to a limited antifungal drug arsenal. One therapeutic challenge faced by clinicians is the significant host toxicity associated with antifungal drugs. Another challenge is the fungistatic mechanism of action of some drugs. Consequently, the identification of fungus-specific drug targets essential for fitness in vivo remains a significant goal of medical mycology research. The trehalose biosynthetic pathway is found in a wide variety of organisms, including human-pathogenic fungi, but not in humans. Genes encoding proteins involved in trehalose biosynthesis are mechanistically linked to the metabolism, cell wall homeostasis, stress responses, and virulence of Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus. While there are a number of pathways for trehalose production across the tree of life, the TPS/TPP (trehalose-6-phosphate synthase/trehalose-6-phosphate phosphatase) pathway is the canonical pathway found in human-pathogenic fungi. Importantly, data suggest that proteins involved in trehalose biosynthesis play other critical roles in fungal metabolism and in vivo fitness that remain to be fully elucidated. By further defining the biology and functions of trehalose and its biosynthetic pathway components in pathogenic fungi, an opportunity exists to leverage this pathway as a potent antifungal drug target. The goal of this review is to cover the known roles of this important molecule and its associated biosynthesis-encoding genes in the human-pathogenic fungi studied to date and to employ these data to critically assess the opportunities and challenges facing development of this pathway as a therapeutic target. PMID:28298477

Indicator microbes correlate with pathogenic bacteria, yeasts and helminthes in sand at a subtropical recreational beach site.

PubMed

Shah, A H; Abdelzaher, A M; Phillips, M; Hernandez, R; Solo-Gabriele, H M; Kish, J; Scorzetti, G; Fell, J W; Diaz, M R; Scott, T M; Lukasik, J; Harwood, V J; McQuaig, S; Sinigalliano, C D; Gidley, M L; Wanless, D; Ager, A; Lui, J; Stewart, J R; Plano, L R W; Fleming, L E

2011-06-01

Research into the relationship between pathogens, faecal indicator microbes and environmental factors in beach sand has been limited, yet vital to the understanding of the microbial relationship between sand and the water column and to the improvement of criteria for better human health protection at beaches. The objectives of this study were to evaluate the presence and distribution of pathogens in various zones of beach sand (subtidal, intertidal and supratidal) and to assess their relationship with environmental parameters and indicator microbes at a non-point source subtropical marine beach. In this exploratory study in subtropical Miami (Florida, USA), beach sand samples were collected and analysed over the course of 6 days for several pathogens, microbial source tracking markers and indicator microbes. An inverse correlation between moisture content and most indicator microbes was found. Significant associations were identified between some indicator microbes and pathogens (such as nematode larvae and yeasts in the genus Candida), which are from classes of microbes that are rarely evaluated in the context of recreational beach use. Results indicate that indicator microbes may predict the presence of some of the pathogens, in particular helminthes, yeasts and the bacterial pathogen Staphylococcus aureus including methicillin-resistant forms. Indicator microbes may thus be useful for monitoring beach sand and water quality at non-point source beaches. The presence of both indicator microbes and pathogens in beach sand provides one possible explanation for human health effects reported at non-point sources beaches. © 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology.

Sensitivity of Candida albicans to essential oils: are they an alternative to antifungal agents?

PubMed

Bona, E; Cantamessa, S; Pavan, M; Novello, G; Massa, N; Rocchetti, A; Berta, G; Gamalero, E

2016-12-01

Candida albicans is an important opportunistic pathogen, responsible for the majority of yeast infections in humans. Essential oils, extracted from aromatic plants, are well-known antimicrobial agents, characterized by a broad spectrum of activities, including antifungal properties. The aim of this work was to assess the sensitivity of 30 different vaginal isolated strains of C. albicans to 12 essential oils, compared to the three main used drugs (clotrimazole, fluconazole and itraconazole). Thirty strains of C. albicans were isolated from vaginal swab on CHROMagar ™ Candida. The agar disc diffusion method was employed to determine the sensitivity to the essential oils. The antifungal activity of the essential oils and antifungal drugs (clotrimazole, itraconazole and fluconazole) were investigated using a microdilution method. Transmission and scanning electron microscopy analyses were performed to get a deep inside on cellular damages. Mint, basil, lavender, tea tree oil, winter savory and oregano essential oils inhibited both the growth and the activity of C. albicans more efficiently than clotrimazole. Damages induced by essential oils at the cellular level were stronger than those caused by clotrimazole. Candida albicans is more sensitive to different essential oils compared to the main used drugs. Moreover, the essential oil affected mainly the cell wall and the membranes of the yeast. The results of this work support the research for new alternatives or complementary therapies against vaginal candidiasis. © 2016 The Society for Applied Microbiology.

Synthesis, antimicrobial evaluation and theoretical prediction of NMR chemical shifts of thiazole and selenazole derivatives with high antifungal activity against Candida spp.

NASA Astrophysics Data System (ADS)

Łączkowski, Krzysztof Z.; Motylewska, Katarzyna; Baranowska-Łączkowska, Angelika; Biernasiuk, Anna; Misiura, Konrad; Malm, Anna; Fernández, Berta

2016-03-01

Synthesis and investigation of antimicrobial activities of novel thiazoles and selenazoles is presented. Their structures were determined using NMR, FAB(+)-MS, HRMS and elemental analyses. To support the experiment, theoretical calculations of the 1H NMR shifts were carried out for representative systems within the DFT B3LYP/6-311++G** approximation which additionally confirmed the structure of investigated compounds. Among the derivatives, compounds 4b, 4h, 4j and 4l had very strong activity against reference strains of Candida albicans ATCC and Candida parapsilosis ATCC 22019 with MIC = 0.49-7.81 μg/ml. In the case of compounds 4b, 4c, 4h - 4j and 4l, the activity was very strong against of Candida spp. isolated from clinical materials, i.e. C. albicans, Candida krusei, Candida inconspicua, Candida famata, Candida lusitaniae, Candida sake, C. parapsilosis and Candida dubliniensis with MIC = 0.24-15.62 μg/ml. The activity of several of these was similar to the activity of commonly used antifungal agent fluconazole. Additionally, compounds 4m - 4s were found to be active against Gram-positive bacteria, both pathogenic staphylococci Staphylococcus aureus ATCC with MIC = 31.25-125 μg/ml and opportunistic bacteria, such as Staphylococcus epidermidis ATCC 12228 and Micrococcus luteus ATCC 10240 with MIC = 7.81-31.25 μg/ml.

Increased filamentous growth of Candida albicans in simulated microgravity.

PubMed

Altenburg, Sara D; Nielsen-Preiss, Sheila M; Hyman, Linda E

2008-03-01

Knowledge of simulated microgravity (SMG)-induced changes in the pathogenicity of microorganisms is important for success of long-term spaceflight. In a previous study using the high aspect ratio vessel bioreactor, we showed that the yeast species Saccharomyces cerevisiae underwent a significant phenotypic response when grown in modeled microgravity, which was reflected in the analysis of gene expression profiles. In this study, we establish that Candida albicans responds to SMG in a similar fashion, demonstrating that there is a conserved response among yeast to this environmental stress. We also report that the growth of C. albicans in SMG results in a morphogenic switch that is consistent with enhanced pathogenicity. Specifically, we observed an increase in filamentous forms of the organism and accompanying changes in the expression of two genes associated with the yeast-hyphal transition. The morphological response may have significant implications for astronauts' safety, as the fungal pathogen may become more virulent during spaceflight.

Diagnostic value of immunoglobulin G antibodies against Candida enolase and fructose-bisphosphate aldolase for candidemia

PubMed Central

2013-01-01

Background The yeast Candida is one of the most frequent pathogens isolated from bloodstream infections and is associated with significant morbidity and mortality. Problems with clinical and microbiological diagnosis of invasive candidiasis (IC) have prompted the development of non-culture-based laboratory methods. Previous reports suggest that serological detection of antibodies might be useful for diagnosing systemic candidiasis. Methods Diagnosis of IC using antibodies against recombinant Candida albicans enolase (Eno) and fructose-bisphosphate aldolase (Fba1) was evaluated. Using recombinant Eno and Fba1 as coating antigens, enzyme-linked immunosorbent assays (ELISAs) were used to analyze sera from patients with candidemia (n = 101), Candida colonization (n = 50), bacteremia (n = 84), invasive aspergillosis (n = 40); and from healthy controls (n = 200). Results The results demonstrated that ELISA detection of anti-Eno and anti-Fba1 IgG distinguished IC from other pathogenic infections in patients and healthy individuals. The sensitivity, specificity, and positive and negative predictive values were 72.3%, 94.7%, 78.5% and 93% for anti-Eno, and 87.1%, 92.8%, 76.5% and 96.4% for anti-Fba1 antibodies, respectively. Combining these two tests improved sensitivity up to 90.1% and negative predictive value up to 97.1%, with specificity and positive predictive values of 90.6% and 72.2%. The tests were specific to the Candida genus and antibody titers were higher for candidemia patients than for controls. Positive antibody tests were obtained before blood culture results for 42.2% of patients for anti-Eno and 51.1% for anti-Fba1. Conclusion These data suggest that tests that detect IgG antibodies against Candida enolase and fructose-bisphosphate aldolase, especially when used in combination, could be a powerful tool for diagnosing IC. PMID:23725337

Diagnostic value of immunoglobulin G antibodies against Candida enolase and fructose-bisphosphate aldolase for candidemia.

PubMed

Li, Fang-Qiu; Ma, Chun-Fang; Shi, Li-Ning; Lu, Jing-Fen; Wang, Ying; Huang, Mei; Kong, Qian-Qian

2013-05-31

The yeast Candida is one of the most frequent pathogens isolated from bloodstream infections and is associated with significant morbidity and mortality. Problems with clinical and microbiological diagnosis of invasive candidiasis (IC) have prompted the development of non-culture-based laboratory methods. Previous reports suggest that serological detection of antibodies might be useful for diagnosing systemic candidiasis. Diagnosis of IC using antibodies against recombinant Candida albicans enolase (Eno) and fructose-bisphosphate aldolase (Fba1) was evaluated. Using recombinant Eno and Fba1 as coating antigens, enzyme-linked immunosorbent assays (ELISAs) were used to analyze sera from patients with candidemia (n = 101), Candida colonization (n = 50), bacteremia (n = 84), invasive aspergillosis (n = 40); and from healthy controls (n = 200). The results demonstrated that ELISA detection of anti-Eno and anti-Fba1 IgG distinguished IC from other pathogenic infections in patients and healthy individuals. The sensitivity, specificity, and positive and negative predictive values were 72.3%, 94.7%, 78.5% and 93% for anti-Eno, and 87.1%, 92.8%, 76.5% and 96.4% for anti-Fba1 antibodies, respectively. Combining these two tests improved sensitivity up to 90.1% and negative predictive value up to 97.1%, with specificity and positive predictive values of 90.6% and 72.2%. The tests were specific to the Candida genus and antibody titers were higher for candidemia patients than for controls. Positive antibody tests were obtained before blood culture results for 42.2% of patients for anti-Eno and 51.1% for anti-Fba1. These data suggest that tests that detect IgG antibodies against Candida enolase and fructose-bisphosphate aldolase, especially when used in combination, could be a powerful tool for diagnosing IC.

The role of Candida albicans AP-1 protein against host derived ROS in in vivo models of infection.

PubMed

Jain, Charu; Pastor, Kelly; Gonzalez, Arely Y; Lorenz, Michael C; Rao, Reeta P

2013-01-01

Candida albicans is a major fungal pathogen of humans, causing mucosal infections that are difficult to eliminate and systemic infections that are often lethal primarily due to defects in the host's innate status. Here we demonstrate the utility of Caenorhabditis elegans, a model host to study innate immunity, by exploring the role of reactive oxygen species (ROS) as a critical innate response against C. albicans infections. Much like a human host, the nematode's innate immune response is activated to produce ROS in response to fungal infection. We use the C. albicans cap1 mutant, which is susceptible to ROS, as a tool to dissect this physiological innate immune response and show that cap1 mutants fail to cause disease and death, except in bli-3 mutant worms that are unable to produce ROS because of a defective NADPH oxidase. We further validate the ROS-mediated host defense mechanism in mammalian phagocytes by demonstrating that chemical inhibition of the NADPH oxidase in cultured macrophages enables the otherwise susceptible cap1 mutant to resists ROS-mediated phagolysis. Loss of CAP1 confers minimal attenuation of virulence in a disseminated mouse model, suggesting that CAP1-independent mechanisms contribute to pathogen survival in vivo. Our findings underscore a central theme in the process of infection-the intricate balance between the virulence strategies employed by C. albicans and the host's innate immune system and validates C. elegans as a simple model host to dissect this balance at the molecular level.

Intra-Genomic Internal Transcribed Spacer Region Sequence Heterogeneity and Molecular Diagnosis in Clinical Microbiology.

PubMed

Zhao, Ying; Tsang, Chi-Ching; Xiao, Meng; Cheng, Jingwei; Xu, Yingchun; Lau, Susanna K P; Woo, Patrick C Y

2015-10-22

Internal transcribed spacer region (ITS) sequencing is the most extensively used technology for accurate molecular identification of fungal pathogens in clinical microbiology laboratories. Intra-genomic ITS sequence heterogeneity, which makes fungal identification based on direct sequencing of PCR products difficult, has rarely been reported in pathogenic fungi. During the process of performing ITS sequencing on 71 yeast strains isolated from various clinical specimens, direct sequencing of the PCR products showed ambiguous sequences in six of them. After cloning the PCR products into plasmids for sequencing, interpretable sequencing electropherograms could be obtained. For each of the six isolates, 10-49 clones were selected for sequencing and two to seven intra-genomic ITS copies were detected. The identities of these six isolates were confirmed to be Candida glabrata (n=2), Pichia (Candida) norvegensis (n=2), Candida tropicalis (n=1) and Saccharomyces cerevisiae (n=1). Multiple sequence alignment revealed that one to four intra-genomic ITS polymorphic sites were present in the six isolates, and all these polymorphic sites were located in the ITS1 and/or ITS2 regions. We report and describe the first evidence of intra-genomic ITS sequence heterogeneity in four different pathogenic yeasts, which occurred exclusively in the ITS1 and ITS2 spacer regions for the six isolates in this study.

Intra-Genomic Internal Transcribed Spacer Region Sequence Heterogeneity and Molecular Diagnosis in Clinical Microbiology

PubMed Central

Zhao, Ying; Tsang, Chi-Ching; Xiao, Meng; Cheng, Jingwei; Xu, Yingchun; Lau, Susanna K. P.; Woo, Patrick C. Y.

2015-01-01

Internal transcribed spacer region (ITS) sequencing is the most extensively used technology for accurate molecular identification of fungal pathogens in clinical microbiology laboratories. Intra-genomic ITS sequence heterogeneity, which makes fungal identification based on direct sequencing of PCR products difficult, has rarely been reported in pathogenic fungi. During the process of performing ITS sequencing on 71 yeast strains isolated from various clinical specimens, direct sequencing of the PCR products showed ambiguous sequences in six of them. After cloning the PCR products into plasmids for sequencing, interpretable sequencing electropherograms could be obtained. For each of the six isolates, 10–49 clones were selected for sequencing and two to seven intra-genomic ITS copies were detected. The identities of these six isolates were confirmed to be Candida glabrata (n = 2), Pichia (Candida) norvegensis (n = 2), Candida tropicalis (n = 1) and Saccharomyces cerevisiae (n = 1). Multiple sequence alignment revealed that one to four intra-genomic ITS polymorphic sites were present in the six isolates, and all these polymorphic sites were located in the ITS1 and/or ITS2 regions. We report and describe the first evidence of intra-genomic ITS sequence heterogeneity in four different pathogenic yeasts, which occurred exclusively in the ITS1 and ITS2 spacer regions for the six isolates in this study. PMID:26506340

Silver nanoparticles induced alterations in multiple cellular targets, which are critical for drug susceptibilities and pathogenicity in fungal pathogen (Candida albicans)

PubMed Central

Radhakrishnan, Venkatraman Srinivasan; Reddy Mudiam, Mohana Krishna; Kumar, Manish; Dwivedi, Surya Prakash; Singh, Surinder Pal; Prasad, Tulika

2018-01-01

Purpose A significant increase in the incidence of fungal infections and drug resistance has been observed in the past decades due to limited availability of broad-spectrum antifungal drugs. Nanomedicines have shown significant antimicrobial potential against various drug-resistant microbes. Silver nanoparticles (AgNps) are known for their antimicrobial properties and lower host toxicity; however, for clinical applications, evaluation of their impact at cellular and molecular levels is essential. The present study aims to understand the cellular and molecular mechanisms of AgNp-induced toxicity in a common fungal pathogen, Candida albicans. Methods AgNps were synthesized by chemical reduction method and characterized using UV–visible spectroscopy, X-ray powder diffraction, transmission electron microscopy, scanning electron microscopy–energy dispersive X-ray spectroscopy, energy dispersive X-ray fluorescence, and zeta potential. The anti-Candida activity of AgNps was assessed by broth microdilution and spot assays. Effects of AgNps on cellular and molecular targets were assessed by monitoring the intracellular reactive oxygen species (ROS) production in the absence and presence of natural antioxidant, changes in surface morphology, cellular ultrastructure, membrane microenvironment, membrane fluidity, membrane ergosterol, and fatty acids. Results Spherical AgNps (10–30 nm) showed minimum inhibitory concentration (minimum concentration required to inhibit the growth of 90% of organisms) at 40 μg/mL. Our results demonstrated that AgNps induced dose-dependent intracellular ROS which exerted antifungal effects; however, even scavenging ROS by antioxidant could not offer protection from AgNp mediated killing. Treatment with AgNps altered surface morphology, cellular ultrastructure, membrane microenvironment, membrane fluidity, ergosterol content, and fatty acid composition, especially oleic acid. Conclusion To summarize, AgNps affected multiple cellular targets crucial for drug resistance and pathogenicity in the fungal cells. The study revealed new cellular targets of AgNps which include fatty acids like oleic acid, vital for hyphal morphogenesis (a pathogenic trait of Candida). Yeast to hypha transition being pivotal for virulence and biofilm formation, targeting virulence might emerge as a new paradigm for developing nano silver-based therapy for clinical applications in fungal therapeutics. PMID:29760548

Prevalence of Candida co-infection in patients with pulmonary tuberculosis.

PubMed

Kali, Arunava; Charles, Mv Pravin; Noyal, Mariya Joseph; Sivaraman, Umadevi; Kumar, Shailesh; Easow, Joshy M

2013-01-01

Candida species are emerging as a potentially pathogenic fungus in patients with broncho-pulmonary diseases. The synergistic growth promoting association of Candida and Mycobacterium tuberculosis has raised increased concern for studying the various Candida spp . and its significance in pulmonary tuberculosis patients during current years. This study was undertaken with the objective of discovering the prevalence of co-infection caused by different Candida species in patients with pulmonary tuberculosis. A total of 75 patients with pulmonary tuberculosis diagnosed by sputum Ziehl-Neelsen staining were included in the study. Candida co-infection was confirmed using the Kahanpaa et al. criteria. Candida species were identified using gram stain morphology, germ tube formation, morphology on cornmeal agar with Tween-80, sugar fermentation tests and HiCrome Candida Agar. Candida co-infection was observed in 30 (40%) of patients with pulmonary tuberculosis. Candida albicans was the most common isolate observed in 50% of the patients with co-infection, followed by C. tropicalis (20%) and C. glabrata (20%). Candida co-infection was found in 62.5% of female patients, while it was observed in only 29.4% of the male patients (P value 0.0133). Mean ± SD age of the patients with C. glabrata infection was 65.83 ± 3.19, while the mean ± SD age of the patients with other Candida infections was 43.25 ± 20.44 (P value 0.0138). Many patients with pulmonary tuberculosis have co-infection with Candida spp. The prevalence of non-albicans Candida species is increasing and may be associated with inadequate response to anti-tubercular drugs. C. glabrata infection has a strong association with old age.

Phosphoglycerate kinase and fructose bisphosphate aldolase of Candida albicans as new antigens recognized by human salivary IgA.

PubMed

Calcedo, Roberto; Ramirez-Garcia, Andoni; Abad, Ana; Rementeria, Aitor; Pontón, José; Hernando, Fernando Luis

2012-01-01

Candida albicans is an opportunistic dimorphic fungus commonly present in the human oral cavity that causes infections in immunocompromised patients. The antigen variability, influenced by growth conditions, is a pathogenicity factor. To determine the effect of nutritional and heat stress on the antigen expression of C. albicans, and to identify major antigens recognized by human salivary secretory immunoglobulin A (sIgA). Under various different nutritional conditions, heat shock was induced in C. albicans cells in stationary and exponential growth phases. The expression of protein determinants of C. albicans was assessed by Western blot analysis against human saliva. The antigens were purified and characterized by two-dimensional electrophoresis and identified by protein microsequencing. Five antigens recognized by salivary IgA were characterized as mannoproteins due to their reactivity with concanavalin A. They did not show reactivity with anti-heat shock protein monoclonal antibodies. Two of them (42 and 36 kDa) were found to be regulated by heat shock and by nutritional stress and they were identified as phosphoglycerate kinase and fructose bisphosphate aldolase, respectively. These glycolytic enzymes are major antigens of C. albicans, and their differential expression and recognition by the mucosal immune response system could be involved in protection against oral infection. Copyright © 2011 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

Interplay between Candida albicans and the Mammalian Innate Host Defense

PubMed Central

Cheng, Shih-Chin; Joosten, Leo A. B.; Kullberg, Bart-Jan

2012-01-01

Candida albicans is both the most common fungal commensal microorganism in healthy individuals and the major fungal pathogen causing high mortality in at-risk populations, especially immunocompromised patients. In this review, we summarize the interplay between the host innate system and C. albicans, ranging from how the host recognizes, responds, and clears C. albicans infection to how C. albicans evades, dampens, and escapes from host innate immunity. PMID:22252867

Looking into Candida albicans infection, host response, and antifungal strategies.

PubMed

Wang, Yan

2015-01-01

Candida albicans, a commonly encountered fungal pathogen, causes diseases varying from superficial mucosal complaints to life-threatening systemic disorders. Among the virulence traits of C. albicans, yeast-to-hypha transition is most widely acknowledged. Host innate immunity to C. albicans critically requires pattern recognition receptors (PRRs), and defence against C. albicans infection is provided by an exquisite interplay between the innate and adaptive arms of the host immune system.

The crystal structure of the secreted aspartic protease 1 from Candida parapsilosis in complex with pepstatin A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dostál, Jiří; Brynda, Jiří; Hrušková-Heidingsfeldová, Olga

2010-09-01

Opportunistic pathogens of the genus Candida cause infections representing a major threat to long-term survival of immunocompromised patients. Virulence of the Candida pathogens is enhanced by production of extracellular proteolytic enzymes and secreted aspartic proteases (Saps) are therefore studied as potential virulence factors and possible targets for therapeutic drug design. Candida parapsilosis is less invasive than C. albicans, however, it is one of the leading causative agents of yeast infections. We report three-dimensional crystal structure of Sapp1p from C. parapsilosis in complex with pepstatin A, the classical inhibitor of aspartic proteases. The structure of Sapp1p was determined from protein isolatedmore » from its natural source and represents the first structure of Sap from C. parapsilosis. Overall fold and topology of Sapp1p is very similar to the archetypic fold of monomeric aspartic protease family and known structures of Sap isoenzymes from C. albicans and Sapt1p from C. tropicalis. Structural comparison revealed noticeable differences in the structure of loops surrounding the active site. This resulted in differential character, shape, and size of the substrate binding site explaining divergent substrate specificities and inhibitor affinities. Determination of structures of Sap isoenzymes from various species might contribute to the development of new Sap-specific inhibitors.« less

Comparative molecular dynamics studies of heterozygous open reading frames of DNA polymerase eta (η) in pathogenic yeast Candida albicans

NASA Astrophysics Data System (ADS)

Satpati, Suresh; Manohar, Kodavati; Acharya, Narottam; Dixit, Anshuman

2017-01-01

Genomic instability in Candida albicans is believed to play a crucial role in fungal pathogenesis. DNA polymerases contribute significantly to stability of any genome. Although Candida Genome database predicts presence of S. cerevisiae DNA polymerase orthologs; functional and structural characterizations of Candida DNA polymerases are still unexplored. DNA polymerase eta (Polη) is unique as it promotes efficient bypass of cyclobutane pyrimidine dimers. Interestingly, C. albicans is heterozygous in carrying two Polη genes and the nucleotide substitutions were found only in the ORFs. As allelic differences often result in functional differences of the encoded proteins, comparative analyses of structural models and molecular dynamic simulations were performed to characterize these orthologs of DNA Polη. Overall structures of both the ORFs remain conserved except subtle differences in the palm and PAD domains. The complementation analysis showed that both the ORFs equally suppressed UV sensitivity of yeast rad30 deletion strain. Our study has predicted two novel molecular interactions, a highly conserved molecular tetrad of salt bridges and a series of π-π interactions spanning from thumb to PAD. This study suggests these ORFs as the homologues of yeast Polη, and due to its heterogeneity in C. albicans they may play a significant role in pathogenicity.

Candida albicans-Induced Epithelial Damage Mediates Translocation through Intestinal Barriers

PubMed Central

2018-01-01

ABSTRACT Life-threatening systemic infections often occur due to the translocation of pathogens across the gut barrier and into the bloodstream. While the microbial and host mechanisms permitting bacterial gut translocation are well characterized, these mechanisms are still unclear for fungal pathogens such as Candida albicans, a leading cause of nosocomial fungal bloodstream infections. In this study, we dissected the cellular mechanisms of translocation of C. albicans across intestinal epithelia in vitro and identified fungal genes associated with this process. We show that fungal translocation is a dynamic process initiated by invasion and followed by cellular damage and loss of epithelial integrity. A screen of >2,000 C. albicans deletion mutants identified genes required for cellular damage of and translocation across enterocytes. Correlation analysis suggests that hypha formation, barrier damage above a minimum threshold level, and a decreased epithelial integrity are required for efficient fungal translocation. Translocation occurs predominantly via a transcellular route, which is associated with fungus-induced necrotic epithelial damage, but not apoptotic cell death. The cytolytic peptide toxin of C. albicans, candidalysin, was found to be essential for damage of enterocytes and was a key factor in subsequent fungal translocation, suggesting that transcellular translocation of C. albicans through intestinal layers is mediated by candidalysin. However, fungal invasion and low-level translocation can also occur via non-transcellular routes in a candidalysin-independent manner. This is the first study showing translocation of a human-pathogenic fungus across the intestinal barrier being mediated by a peptide toxin. PMID:29871918

Comparative analysis of cell wall surface glycan expression in Candida albicans and Saccharomyces cerevisiae yeasts by flow cytometry.

PubMed

Martínez-Esparza, M; Sarazin, A; Jouy, N; Poulain, D; Jouault, T

2006-07-31

The yeast Candida albicans is an opportunistic pathogen, part of the normal human microbial flora that causes infections in immunocompromised individuals with a high morbidity and mortality levels. Recognition of yeasts by host cells is based on components of the yeast cell wall, which are considered part of its virulence attributes. Cell wall glycans play an important role in the continuous interchange that regulates the balance between saprophytism and parasitism, and also between resistance and infection. Some of these molecular entities are expressed both by the pathogenic yeast C. albicans and by Saccharomyces cerevisiae, a related non-pathogenic yeast, involving similar molecular mechanisms and receptors for recognition. In this work we have exploited flow cytometry methods for probing surface glycans of the yeasts. We compared glycan expression by C. albicans and by S. cerevisiae, and studied the effect of culture conditions. Our results show that the expression levels of alpha- and beta-linked mannosides as well as beta-glucans can be successfully evaluated by flow cytometry methods using different antibodies independent of agglutination reactions. We also found that the surface expression pattern of beta-mannosides detected by monoclonal or polyclonal antibodies are differently modulated during the growth course. These data indicate that the yeast beta-mannosides exposed on mannoproteins and/or phospholipomannan are increased in stationary phase, whereas those linked to mannan are not affected by the yeast growth phase. The cytometric method described here represents a useful tool to investigate to what extent C. albicans is able to regulate its glycan surface expression and therefore modify its virulence properties.

Probing the Active Site of Candida Glabrata Dihydrofolate Reductase with High Resolution Crystal Structures and the Synthesis of New Inhibitors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, J.; Bolstad, D; Smith, A

2009-01-01

Candida glabrata, a fungal strain resistant to many commonly administered antifungal agents, has become an emerging threat to human health. In previous work, we validated that the essential enzyme, dihydrofolate reductase, is a drug target in C. glabrata. Using a crystal structure of dihydrofolate reductase from C. glabrata bound to an initial lead compound, we designed a class of biphenyl antifolates that potently and selectively inhibit both the enzyme and the growth of the fungal culture. In this work, we explore the structure-activity relationships of this class of antifolates with four new high resolution crystal structures of enzyme:inhibitor complexes andmore » the synthesis of four new inhibitors. The designed inhibitors are intended to probe key hydrophobic pockets visible in the crystal structure. The crystal structures and an evaluation of the new compounds reveal that methyl groups at the meta and para positions of the distal phenyl ring achieve the greatest number of interactions with the pathogenic enzyme and the greatest degree of selectivity over the human enzyme. Additionally, antifungal activity can be tuned with substitution patterns at the propargyl and para-phenyl positions.« less

Generational distribution of a Candida glabrata population: Resilient old cells prevail, while younger cells dominate in the vulnerable host.

PubMed

Bouklas, Tejas; Alonso-Crisóstomo, Luz; Székely, Tamás; Diago-Navarro, Elizabeth; Orner, Erika P; Smith, Kalie; Munshi, Mansa A; Del Poeta, Maurizio; Balázsi, Gábor; Fries, Bettina C

2017-05-01

Similar to other yeasts, the human pathogen Candida glabrata ages when it undergoes asymmetric, finite cell divisions, which determines its replicative lifespan. We sought to investigate if and how aging changes resilience of C. glabrata populations in the host environment. Our data demonstrate that old C. glabrata are more resistant to hydrogen peroxide and neutrophil killing, whereas young cells adhere better to epithelial cell layers. Consequently, virulence of old compared to younger C. glabrata cells is enhanced in the Galleria mellonella infection model. Electron microscopy images of old C. glabrata cells indicate a marked increase in cell wall thickness. Comparison of transcriptomes of old and young C. glabrata cells reveals differential regulation of ergosterol and Hog pathway associated genes as well as adhesion proteins, and suggests that aging is accompanied by remodeling of the fungal cell wall. Biochemical analysis supports this conclusion as older cells exhibit a qualitatively different lipid composition, leading to the observed increased emergence of fluconazole resistance when grown in the presence of fluconazole selection pressure. Older C. glabrata cells accumulate during murine and human infection, which is statistically unlikely without very strong selection. Therefore, we tested the hypothesis that neutrophils constitute the predominant selection pressure in vivo. When we altered experimentally the selection pressure by antibody-mediated removal of neutrophils, we observed a significantly younger pathogen population in mice. Mathematical modeling confirmed that differential selection of older cells is sufficient to cause the observed demographic shift in the fungal population. Hence our data support the concept that pathogenesis is affected by the generational age distribution of the infecting C. glabrata population in a host. We conclude that replicative aging constitutes an emerging trait, which is selected by the host and may even play an unanticipated role in the transition from a commensal to a pathogen state.

Convergent Evolution of Calcineurin Pathway Roles in Thermotolerance and Virulence in Candida glabrata

PubMed Central

Chen, Ying-Lien; Konieczka, Jay H.; Springer, Deborah J.; Bowen, Samantha E.; Zhang, Jing; Silao, Fitz Gerald S.; Bungay, Alice Alma C.; Bigol, Ursela G.; Nicolas, Marilou G.; Abraham, Soman N.; Thompson, Dawn A.; Regev, Aviv; Heitman, Joseph

2012-01-01

Candida glabrata is an emerging human fungal pathogen that is frequently drug tolerant, resulting in difficulties in treatment and a higher mortality in immunocompromised patients. The calcium-activated protein phosphatase calcineurin plays critical roles in controlling drug tolerance, hyphal growth, and virulence in diverse fungal pathogens via distinct mechanisms involving survival in serum or growth at host temperature (37° and higher). Here, we comprehensively studied the calcineurin signaling cascade in C. glabrata and found novel and uncharacterized functions of calcineurin and its downstream target Crz1 in governing thermotolerance, intracellular architecture, and pathogenesis in murine ocular, urinary tract, and systemic infections. This represents a second independent origin of a role for calcineurin in thermotolerant growth of a major human fungal pathogen, distinct from that which arose independently in Cryptococcus neoformans. Calcineurin also promotes survival of C. glabrata in serum via mechanisms distinct from C. albicans and thereby enables establishment of tissue colonization in a murine systemic infection model. To understand calcineurin signaling in detail, we performed global transcript profiling analysis and identified calcineurin- and Crz1-dependent genes in C. glabrata involved in cell wall biosynthesis, heat shock responses, and calcineurin function. Regulators of calcineurin (RCN) are a novel family of calcineurin modifiers, and two members of this family were identified in C. glabrata: Rcn1 and Rcn2. Our studies demonstrate that Rcn2 expression is controlled by calcineurin and Crz1 to function as a feedback inhibitor of calcineurin in a circuit required for calcium tolerance in C. glabrata. In contrast, the calcineurin regulator Rcn1 activates calcineurin signaling. Interestingly, neither Rcn1 nor Rcn2 is required for virulence in a murine systemic infection model. Taken together, our findings show that calcineurin signaling plays critical roles in thermotolerance and virulence, and that Rcn1 and Rcn2 have opposing functions in controlling calcineurin signaling in C. glabrata. PMID:22690377

Effects of hemin, CO2, and pH on the branching of Candida albicans filamentous forms.

PubMed

Jakab, Ágnes; Antal, Károly; Emri, Tamás; Boczonádi, Imre; Imre, Alexandra; Gebri, Enikő; Majoros, László; Pfliegler, Walter Péter; Szarka, Máté; Balla, György; Balla, József; Pócsi, István

2016-12-01

Morphological transitions of wild-type and oxidative stress-tolerant Candida albicans strains were followed in the RPMI-FBS culture medium at pH values and CO 2 levels characteristic for the anatomical niches inhabited by this opportunistic human pathogen fungus, including the oral cavity as well as the intestinal and vaginal lumens. Selected cultures were also supplemented with hemin modeling bleedings. Germination as well as elongation and branching of hyphae were monitored in the cultures using time-lapse video microscopy. Unexpectedly, branching time, which is defined as the time taken until the first branch of hypha emerges for the first time after germination, correlated well with alterations in the environmental conditions meanwhile no such correlations were found for germination time (time lasted until the appearance of the germination tube). Based on these observations, hypotheses were set up to estimate the significance of branching time in the pathogenesis of both superficial and systemic candidiases.

Cell wall glycans and soluble factors determine the interactions between the hyphae of Candida albicans and Pseudomonas aeruginosa.

PubMed

Brand, Alexandra; Barnes, Julia D; Mackenzie, Kevin S; Odds, Frank C; Gow, Neil A R

2008-10-01

The fungus, Candida albicans, and the bacterium, Pseudomonas aeruginosa, are opportunistic human pathogens that have been coisolated from diverse body sites. Pseudomonas aeruginosa suppresses C. albicans proliferation in vitro and potentially in vivo but it is the C. albicans hyphae that are killed while yeast cells are not. We show that hyphal killing involves both contact-mediated and soluble factors. Bacterial culture filtrates contained heat-labile soluble factors that killed C. albicans hyphae. In cocultures, localized points of hyphal lysis were observed, suggesting that adhesion and subsequent bacteria-mediated cell wall lysis is involved in the killing of C. albicans hyphae. The glycosylation status of the C. albicans cell wall affected the rate of contact-dependent killing because mutants with severely truncated O-linked, but not N-linked, glycans were hypersensitive to Pseudomonas-mediated killing. Deletion of HWP1, ALS3 or HYR1, which encode major hypha-associated cell wall proteins, had no effect on fungal susceptibility.

Clinical Saccharomyces cerevisiae isolates cannot cross the epithelial barrier in vitro.

PubMed

Pérez-Torrado, Roberto; Llopis, Silvia; Jespersen, Lene; Fernández-Espinar, Teresa; Querol, Amparo

2012-06-15

Saccharomyces cerevisiae is generally considered to be a safe organism and is essential to produce many different kinds of foods as well as being widely used as a dietary supplement. However, several isolates, which are genetically related to brewing and baking yeasts, have shown virulent traits, being able to produce human infections in immunodeficient patients. Previously it has been shown that the administration of S. cerevisiae clinical isolates can lead to systemic infections, reaching several organs in murine systems. In this work, we studied S. cerevisiae clinical isolates in an in vitro intestinal epithelial barrier model, comparing their behaviour with that of several strains of the related pathogens Candida glabrata and Candida albicans. The results showed that, in contrast to C. glabrata and C. albicans, S. cerevisiae was not able to cross the intestinal barrier. We concluded that S. cerevisiae can only perform opportunistic or passive crossings when epithelial barrier integrity is previously compromised. Copyright © 2012 Elsevier B.V. All rights reserved.

Inhibitors of the Glyoxylate Cycle Enzyme ICL1 in Candida albicans for Potential Use as Antifungal Agents

PubMed Central

Cheah, Hong-Leong; Lim, Vuanghao; Sandai, Doblin

2014-01-01

Candida albicans is an opportunistic pathogen that causes candidiasis in humans. In recent years, metabolic pathways in C. albicans have been explored as potential antifungal targets to treat candidiasis. The glyoxylate cycle, which enables C. albicans to survive in nutrient-limited host niches and its. Key enzymes (e.g., isocitrate lyase (ICL1), are particularly attractive antifungal targets for C. albicans. In this study, we used a new screening approach that better reflects the physiological environment that C. albicans cells experience during infection to identify potential inhibitors of ICL. Three compounds (caffeic acid (CAFF), rosmarinic acid (ROS), and apigenin (API)) were found to have antifungal activity against C. albicans when tested under glucose-depleted conditions. We further confirmed the inhibitory potential of these compounds against ICL using the ICL enzyme assay. Lastly, we assessed the bioavailability and toxicity of these compounds using Lipinski's rule-of-five and ADMET analysis. PMID:24781056

The evolution of drug resistance in clinical isolates of Candida albicans

PubMed Central

Guiducci, Candace; Martinez, Diego A; Delorey, Toni; Li, Bi yu; White, Theodore C; Cuomo, Christina; Rao, Reeta P; Berman, Judith; Thompson, Dawn A; Regev, Aviv

2015-01-01

Candida albicans is both a member of the healthy human microbiome and a major pathogen in immunocompromised individuals. Infections are typically treated with azole inhibitors of ergosterol biosynthesis often leading to drug resistance. Studies in clinical isolates have implicated multiple mechanisms in resistance, but have focused on large-scale aberrations or candidate genes, and do not comprehensively chart the genetic basis of adaptation. Here, we leveraged next-generation sequencing to analyze 43 isolates from 11 oral candidiasis patients. We detected newly selected mutations, including single-nucleotide polymorphisms (SNPs), copy-number variations and loss-of-heterozygosity (LOH) events. LOH events were commonly associated with acquired resistance, and SNPs in 240 genes may be related to host adaptation. Conversely, most aneuploidies were transient and did not correlate with drug resistance. Our analysis also shows that isolates also varied in adherence, filamentation, and virulence. Our work reveals new molecular mechanisms underlying the evolution of drug resistance and host adaptation. DOI: http://dx.doi.org/10.7554/eLife.00662.001 PMID:25646566

Screening of antimicrobial activity of macroalgae extracts from the Moroccan Atlantic coast.

PubMed

El Wahidi, M; El Amraoui, B; El Amraoui, M; Bamhaoud, T

2015-05-01

The aim of this work is the screening of the antimicrobial activity of seaweed extracts against pathogenic bacteria and yeasts. The antimicrobial activity of the dichloromethane and ethanol extracts of ten marine macroalgae collected from the Moroccan's Atlantic coast (El-Jadida) was tested against two Gram+ (Bacillus subtilis and Staphylococcus aureus) and two Gram- (Escherichia coli and Pseudomonas aeruginosa) human pathogenic bacteria, and against two pathogenic yeasts (Candida albicans and Cryptococcus neoformans) using the agar disk-diffusion method. Seven algae (70%) of ten seaweeds are active against at least one pathogenic microorganisms studied. Five (50%) are active against the two studied yeast with an inhibition diameter greater than 15 mm for Cystoseira brachycarpa. Six (60%) seaweeds are active against at least one studied bacteria with five (50%) algae exhibiting antibacterial inhibition diameter greater than 15 mm. Cystoseira brachycarpa, Cystoseira compressa, Fucus vesiculosus, and Gelidium sesquipedale have a better antimicrobial activity with a broad spectrum antimicrobial and are a potential source of antimicrobial compounds and can be subject of isolation of the natural antimicrobials. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Identification of salivary components that induce transition of hyphae to yeast in Candida albicans.

PubMed

Leito, Jelani T D; Ligtenberg, Antoon J M; Nazmi, Kamran; Veerman, Enno C I

2009-10-01

Candida albicans, the major human fungal pathogen, undergoes a reversible morphological transition from single yeast cells to pseudohyphae and hyphae filaments. The hyphae form is considered the most invasive form of the fungus. The purpose of this study is to investigate the effect of saliva on hyphae growth of C. albicans. Candida albicans hyphae were inoculated in Roswell Park Memorial Institute medium with whole saliva, parotid saliva or buffer mimicking the saliva ion composition, and cultured for 18 h at 37 degrees C under aerobic conditions with 5% CO(2). Whole saliva and parotid saliva induced transition to yeast growth, whereas the culture with buffer remained in the hyphae form. Parotid saliva was fractionated on a reverse-phase C8 column and each fraction was tested for inducing transition to yeast growth. By immunoblotting, the salivary component in the active fraction was identified as statherin, a phosphoprotein of 43 amino acids that has been implicated in remineralization of the teeth. Synthetically made statherin induced transition of hyphae to yeast. By deletion of five amino acids at the negatively charged N-terminal site (DpSpSEE), yeast-inducing activity and binding to C. albicans were increased. In conclusion, statherin induces transition to yeast of C. albicans hyphae and may thus contribute to the oral defense against candidiasis.

Efficient click chemistry towards fatty acids containing 1,2,3-triazole: Design and synthesis as potential antifungal drugs for Candida albicans.

PubMed

Fu, Nina; Wang, Suiliang; Zhang, Yuqian; Zhang, Caixia; Yang, Dongliang; Weng, Lixing; Zhao, Baomin; Wang, Lianhui

2017-08-18

Candida is an important opportunistic human fungal pathogen. The cis-2-dodecenoic acid (BDSF) showing in vitro activity of against C. albicans growth, germ-tube germination and biofilm formation has been a potential inhibitor for Candida and other fungi. In this study, facile synthetic strategies toward a novel family of BDSF analogue, 1-alkyl-1H-1,2,3-triazole-4-carboxylic acids (ATCs) was developed. The straightforward synthetic method including converting the commercial available alkyl bromide to alkyl azide, consequently with a typical click chemistry method, copper(II) sulfate and sodium ascorbate as catalyst in water to furnish ATCs with mild to good yields. According to antifungal assay, 1-decyl-4,5-dihydro-1H-1,2,3-triazole-4-carboxylic acid (5d) showed antifungal capability slightly better than BDSF. The 1,2,3-triazole unit played a crucial role for the bioactivity of ATCs was also confirmed when compared with two alkyl-aromatic carboxylic acids. Given its simplicity, high antifungal activity, and wide availability of compounds with halide atoms on the end part of the alkyl chains, the method can be extended to develop more excellent ATC drugs for accomplishing the challenges in future antifungal applications. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Characterization and Reclassification of Yeasts Used for Biological Control of Postharvest Diseases of Fruits and Vegetables

PubMed Central

McLaughlin, R. J.; Wilson, C. L.; Chalutz, E.; Kurtzman, C. P.; Fett, W. F.; Osman, S. F.

1990-01-01

In previous studies workers have shown that three yeast strains (strains US-7, 82, and 101) have biological control activity against various postharvest fungal pathogens of fruits and vegetables, including Penicillium rots of apples and citrus and Botrytis rot of apples. In these reports the researchers have described these strains as Debaryomyces hansenii (anamorph, Candida famata) or Candida sp. strains. In this study we performed additional physiological, DNA reassociation, and mannan characterization tests that clearly established a new taxonomic classification for these strains, Candida guilliermondii. We also propose amendment of the physiological test profile in the taxonomic description of C. guilliermondii. PMID:16348361

In vitro inhibitory activities of magnolol against Candida spp.

PubMed

Zhou, Peiru; Fu, Jingya; Hua, Hong; Liu, Xiaosong

2017-01-01

Candida spp. cause various infections involving the skin, mucosa, deep tissues, and even life-threatening candidemia. They are regarded as an important pathogen of nosocomial bloodstream infection, with a high mortality rate. As a result of prolonged exposure to azoles, the therapeutic failure associated with azoles resistance has become a serious challenge in clinical situations. Therefore, novel, alternative antifungals are required urgently. In the present study, the CLSI M-27A broth microdilution method and the 2,3-Bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) reduction assay were used to evaluate the antifungal effects of magnolol against various standard Candida strains in planktonic mode and biofilm formation, respectively. The antifungal activity of magnolol was demonstrated in planktonic C. albicans and non-albicans Candida species, especially fluconazole-resistant Candida krusei , with the minimum inhibitory concentrations ranging from 10 to 40 μg/mL. The BMIC 90 (minimum concentration with 90% Candida biofilm inhibited) values of magnolol ranged from 20 to 160 μg/mL, whereas the BMIC 90 values of fluconazole were more than 128 μg/mL. As an alternative and broad-spectrum antifungal agent, magnolol might be of benefit to the treatment of refractory Candida infection.

[Aetiology of candidiasis in paediatric patients: Comparative analysis with adult patients].

PubMed

Gil-Tomás, Jesús J; Colomina-Rodríguez, Javier

2016-01-01

Candida spp. represents a group of commensal yeasts that can act as pathogens and cause candidiasis in different anatomical locations. The aim of this study was to perform an epidemiological and comparative analysis between the isolates of Candida spp. in clinical specimens during a three year-period (2010-2012) from children (0-14 years) and adults (15-99 years) in the Valencian Community (RedMIVA). The microbiological surveillance network of Valencian Community was used as the information source. Candida was isolated in 52,436 patients (1,604 [3.1%] children and 50,832 [96.9%] adults). Candida albicans was significantly (p<0.05) the predominant species in both age groups, and in almost every type of clinical specimen. The distribution of other species varied depending on the sample type and age group. In blood specimens, Candida parapsilosis followed by C. albicans, Candida famata and Candida lusitaniae were the main species found in children, whereas C. albicans followed by C. parapsilosis, Candida glabrata and Candida tropicalis were the predominant species in adults. In sterile fluids, urine and lower respiratory tract samples, C. parapsilosis was the second most prevalent species in the children group, while C. glabrata and C. tropicalis were the main second species in adults. Copyright © 2015 Asociación Española de Micología. Published by Elsevier Espana. All rights reserved.

Candida infection in oral leukoplakia: an unperceived public health problem.

PubMed

Dilhari, Ayomi; Weerasekera, Manjula M; Siriwardhana, Anusha; Maheshika, Oshanthi; Gunasekara, Chinthika; Karunathilaka, Sunil; Nagahawatte, Ajith; Fernando, Neluka

2016-10-01

The study aimed to determine the proportion, known risk factors and etiology for Candida infection in leukoplakia lesions among patients with oral leukoplakia attending the Oral and Maxillofacial Clinic at a Tertiary Care Hospital in Sri Lanka. Eighty clinically suspected oral leukoplakia patients were included. Two oral swabs each, from leukoplakia patients: one swab from the lesion and the other one from the contralateral unaffected corresponding area (as a control) were collected. Direct microscopy and culture followed by colony count and phenotypic identification were performed to identify pathogenic Candida species. Candida infection was seen in 47% of patients with oral leukoplakia. Candida albicans (94.7%) was the most common Candida species followed by Candida tropicalis (5.3%). Majority of Candida-infected lesions were seen in the buccal mucosa region. Alteration of taste (p = 0.021), having other oral lesions (p = 0.008), angular cheilitis (p = 0.024) and periodontitis (p = 0.041) showed a significant association with Candida-associated leukoplakia. Increasing age showed a significant tendency for Candida infection (p = 0.020). Smoking (p = 0.026) and betel-quid chewing (p = 0.006) were also found to be significantly associated, although alcohol consumption alone did not show a significant association. Oral leukoplakia patients who had all three habits: alcohol consumption, smoking and betel-quid chewing had a significant association with Candida infection (p = 0.004). Patients who had a combination of risk factors: smoking, betel-quid chewing and alcohol consumption were seen to have a significant association with Candida infection. Further betel-quid chewing alone and smoking singly was also significantly associated with Candida infection in oral leukoplakia.

Dandruff-associated Malassezia genomes reveal convergent and divergent virulence traits shared with plant and human fungal pathogens.

PubMed

Xu, Jun; Saunders, Charles W; Hu, Ping; Grant, Raymond A; Boekhout, Teun; Kuramae, Eiko E; Kronstad, James W; Deangelis, Yvonne M; Reeder, Nancy L; Johnstone, Kevin R; Leland, Meredith; Fieno, Angela M; Begley, William M; Sun, Yiping; Lacey, Martin P; Chaudhary, Tanuja; Keough, Thomas; Chu, Lien; Sears, Russell; Yuan, Bo; Dawson, Thomas L

2007-11-20

Fungi in the genus Malassezia are ubiquitous skin residents of humans and other warm-blooded animals. Malassezia are involved in disorders including dandruff and seborrheic dermatitis, which together affect >50% of humans. Despite the importance of Malassezia in common skin diseases, remarkably little is known at the molecular level. We describe the genome, secretory proteome, and expression of selected genes of Malassezia globosa. Further, we report a comparative survey of the genome and secretory proteome of Malassezia restricta, a close relative implicated in similar skin disorders. Adaptation to the skin environment and associated pathogenicity may be due to unique metabolic limitations and capabilities. For example, the lipid dependence of M. globosa can be explained by the apparent absence of a fatty acid synthase gene. The inability to synthesize fatty acids may be complemented by the presence of multiple secreted lipases to aid in harvesting host lipids. In addition, an abundance of genes encoding secreted hydrolases (e.g., lipases, phospholipases, aspartyl proteases, and acid sphingomyelinases) was found in the M. globosa genome. In contrast, the phylogenetically closely related plant pathogen Ustilago maydis encodes a different arsenal of extracellular hydrolases with more copies of glycosyl hydrolase genes. M. globosa shares a similar arsenal of extracellular hydrolases with the phylogenetically distant human pathogen, Candida albicans, which occupies a similar niche, indicating the importance of host-specific adaptation. The M. globosa genome sequence also revealed the presence of mating-type genes, providing an indication that Malassezia may be capable of sex.

Dandruff-associated Malassezia genomes reveal convergent and divergent virulence traits shared with plant and human fungal pathogens

PubMed Central

Xu, Jun; Saunders, Charles W.; Hu, Ping; Grant, Raymond A.; Boekhout, Teun; Kuramae, Eiko E.; Kronstad, James W.; DeAngelis, Yvonne M.; Reeder, Nancy L.; Johnstone, Kevin R.; Leland, Meredith; Fieno, Angela M.; Begley, William M.; Sun, Yiping; Lacey, Martin P.; Chaudhary, Tanuja; Keough, Thomas; Chu, Lien; Sears, Russell; Yuan, Bo; Dawson, Thomas L.

2007-01-01

Fungi in the genus Malassezia are ubiquitous skin residents of humans and other warm-blooded animals. Malassezia are involved in disorders including dandruff and seborrheic dermatitis, which together affect >50% of humans. Despite the importance of Malassezia in common skin diseases, remarkably little is known at the molecular level. We describe the genome, secretory proteome, and expression of selected genes of Malassezia globosa. Further, we report a comparative survey of the genome and secretory proteome of Malassezia restricta, a close relative implicated in similar skin disorders. Adaptation to the skin environment and associated pathogenicity may be due to unique metabolic limitations and capabilities. For example, the lipid dependence of M. globosa can be explained by the apparent absence of a fatty acid synthase gene. The inability to synthesize fatty acids may be complemented by the presence of multiple secreted lipases to aid in harvesting host lipids. In addition, an abundance of genes encoding secreted hydrolases (e.g., lipases, phospholipases, aspartyl proteases, and acid sphingomyelinases) was found in the M. globosa genome. In contrast, the phylogenetically closely related plant pathogen Ustilago maydis encodes a different arsenal of extracellular hydrolases with more copies of glycosyl hydrolase genes. M. globosa shares a similar arsenal of extracellular hydrolases with the phylogenetically distant human pathogen, Candida albicans, which occupies a similar niche, indicating the importance of host-specific adaptation. The M. globosa genome sequence also revealed the presence of mating-type genes, providing an indication that Malassezia may be capable of sex. PMID:18000048

Towards New Antifolates Targeting Eukaryotic Opportunistic Infections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, J.; Bolstad, D; Bolstad, E

2009-01-01

Trimethoprim, an antifolate commonly prescribed in combination with sulfamethoxazole, potently inhibits several prokaryotic species of dihydrofolate reductase (DHFR). However, several eukaryotic pathogenic organisms are resistant to trimethoprim, preventing its effective use as a therapeutic for those infections. We have been building a program to reengineer trimethoprim to more potently and selectively inhibit eukaryotic species of DHFR as a viable strategy for new drug discovery targeting several opportunistic pathogens. We have developed a series of compounds that exhibit potent and selective inhibition of DHFR from the parasitic protozoa Cryptosporidium and Toxoplasma as well as the fungus Candida glabrata. A comparison ofmore » the structures of DHFR from the fungal species Candida glabrata and Pneumocystis suggests that the compounds may also potently inhibit Pneumocystis DHFR.« less

Tenebrio molitor (Coleoptera: Tenebrionidae) as an alternative host to study fungal infections.

PubMed

de Souza, Patrícia Canteri; Morey, Alexandre Tadachi; Castanheira, Gabriel Marcondes; Bocate, Karla Paiva; Panagio, Luciano Aparecido; Ito, Fabio Augusto; Furlaneto, Márcia Cristina; Yamada-Ogatta, Sueli Fumie; Costa, Idessânia Nazareth; Mora-Montes, Hector Manuel; Almeida, Ricardo Sergio

2015-11-01

Models of host–pathogen interactions are crucial for the analysis of microbial pathogenesis. In this context, invertebrate hosts, including Drosophila melanogaster (fruit fly), Caenorhabditis elegans (nematode) and Galleria mellonella (moth), have been used to study the pathogenesis of fungi and bacteria. Each of these organisms offers distinct benefits in elucidating host–pathogen interactions. In this study,we present a newinvertebrate infection model to study fungal infections: the Tenebrio molitor (beetle) larvae. Here we performed T. molitor larvae infection with one of two important fungal human pathogens, Candida albicans or Cryptococcus neoformans, and analyzed survival curves and larva infected tissues.We showed that increasing concentrations of inoculum of both fungi resulted in increased mortality rates, demonstrating the efficiency of the method to evaluate the virulence of pathogenic yeasts. Additionally, following 12 h post-infection, C. albicans formsmycelia, spreading its hyphae through the larva tissue,whilst GMS stain enabled the visualization of C. neoformans yeast and theirmelanin capsule. These larvae are easier to cultivate in the laboratory than G. mellonella larvae, and offer the same benefits. Therefore, this insect model could be a useful alternative tool to screen clinical pathogenic yeast strainswith distinct virulence traits or different mutant strains.

Secoiridoids from Gentiana siphonantha.

PubMed

Tan, R X; Kong, L D

1997-11-01

Repeated fractionations of the methanol extract of the subterranean parts (rhizomes and roots) of Gentiana siphonantha afforded two new and five known secoiridoids, in addition to the widespread plant constituents beta-sitiosterol, daucosterol and oleanolic acid. The structures of the new acyl secoiridoid glycosides were elucidated as 6'-gentisoyl 8-epikingiside and 2'-gentisoyl gelidoside mainly by a combination of high field NMR techniques. The known secoiridoids were identified as gentiolactone, gentiopicroside, sweroside, gelidoside and trifloroside. None of these constituents was active against human pathogenic fungi (Candida albican, Aspergillus flavus and Trichoderma viride). The chemotaxonomic significance of the isolates is discussed briefly.

Plants from Lamiaceae family as source of antifungal molecules in humane and veterinary medicine.

PubMed

Waller, Stefanie Bressan; Cleff, Marlete Brum; Serra, Emanoele Figueiredo; Silva, Anna Luiza; Gomes, Angelita Dos Reis; de Mello, João Roberto Braga; de Faria, Renata Osório; Meireles, Mário Carlos Araújo

2017-03-01

This work aimed to review the main plants of Lamiaceae family with activity against pathogenic fungi of medical and veterinary interest. Published studies in the main international databases between January 2002 and June 2016 showed that 55 botanical species belonging to 27 genus presented antifungal activity in different forms of extractions, mainly essential oils. Pathogenic fungi of Aspergillus spp., Candida spp., Malassezia spp., Cryptococcus spp., Sporothrix spp., Microsporum spp., Trichophyton spp. and Epidermophyton spp. genus were in vitro sensitive to several plants of Lamiaceae family. Chemical molecules isolated were described as promising use as antifungals in mycoses, highlighting estragole, 1,8-cineole, terpineol-4, γ-terpinene, among others. However, it should be alert to need of universal standardization in the laboratories tests with natural products. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mixed Fungal Lung Infection with Aspergillus Fumigatus and Candida Albicans in a Immunocomprimised Patient: Case Report

PubMed Central

Vipparti, Haritha

2014-01-01

The frequency of invasive, opportunistic mycoses has increased significantly over the past 2 decades. In the immune-compromised host, many fungi, including species of fungi typically considered non-pathogenic, have the potential to cause serious morbidity and mortality. Here we report a rare case of mixed fungal infection of the lung with Candida albicans and Aspergillus fumigatus in a patient on prolonged steroid therapy. PMID:24959447

Central Role of the Trehalose Biosynthesis Pathway in the Pathogenesis of Human Fungal Infections: Opportunities and Challenges for Therapeutic Development.

PubMed

Thammahong, Arsa; Puttikamonkul, Srisombat; Perfect, John R; Brennan, Richard G; Cramer, Robert A

2017-06-01

Invasive fungal infections cause significant morbidity and mortality in part due to a limited antifungal drug arsenal. One therapeutic challenge faced by clinicians is the significant host toxicity associated with antifungal drugs. Another challenge is the fungistatic mechanism of action of some drugs. Consequently, the identification of fungus-specific drug targets essential for fitness in vivo remains a significant goal of medical mycology research. The trehalose biosynthetic pathway is found in a wide variety of organisms, including human-pathogenic fungi, but not in humans. Genes encoding proteins involved in trehalose biosynthesis are mechanistically linked to the metabolism, cell wall homeostasis, stress responses, and virulence of Candida albicans , Cryptococcus neoformans , and Aspergillus fumigatus . While there are a number of pathways for trehalose production across the tree of life, the TPS/TPP (trehalose-6-phosphate synthase/trehalose-6-phosphate phosphatase) pathway is the canonical pathway found in human-pathogenic fungi. Importantly, data suggest that proteins involved in trehalose biosynthesis play other critical roles in fungal metabolism and in vivo fitness that remain to be fully elucidated. By further defining the biology and functions of trehalose and its biosynthetic pathway components in pathogenic fungi, an opportunity exists to leverage this pathway as a potent antifungal drug target. The goal of this review is to cover the known roles of this important molecule and its associated biosynthesis-encoding genes in the human-pathogenic fungi studied to date and to employ these data to critically assess the opportunities and challenges facing development of this pathway as a therapeutic target. Copyright © 2017 American Society for Microbiology.

Candida parapsilosis is a Significant Neonatal Pathogen: A Systematic Review and Meta-Analysis

PubMed Central

Pammi, Mohan; Holland, Linda; Butler, Geraldine; Gacser, Attila; Bliss, Joseph M.

2013-01-01

Background Candida is the third most common cause of late-onset neonatal sepsis in infants born at < 1500 g. C. parapsilosis infections are increasingly reported in preterm neonates in association with indwelling catheters. Methods We systematically reviewed neonatal literature and synthesized data pertaining to percentage of C. parapsilosis infections and mortality by meta-analyses. We also reviewed risk factors, virulence determinants, antimicrobial susceptibility patterns and outlined clinical management strategies. Results C. parapsilosis infections comprised 33.47 % [95% CI, 30.02, 37.31] of all neonatal Candida infections. C. parapsilosis rates were similar in studies performed before the year 2000, 33.53 % [95% CI, 30.06, 37.40] (28 studies), to those after 2000, 27.00% [95% CI, 8.25, 88.37] (8 studies). The mortality due to neonatal Candida parapsilosis infections was 10.02% [95% CI, 7.66, 13.12]. Geographical variations in C. parapsilosis infections included a low incidence in Europe and higher incidence in North America and Australia. Biofilm formation was a significant virulence determinant and predominant risk factors for C. parapsilosis infections were prematurity, prior colonization and catheterization. Amphotericin B remains the antifungal drug of choice and combination therapy with caspofungin or other echinocandins may be considered in resistant cases. Conclusion C. parapsilosis is a significant neonatal pathogen, comprises a third of all Candida infections and is associated with 10% mortality. Availability of tools for genetic manipulation of this organism will identify virulence determinants and organism characteristics that may explain predilection for preterm neonates. Strategies to prevent horizontal transmission in the neonatal unit are paramount in decreasing infection rates. PMID:23340551

Modulation of Morphogenesis in Candida albicans by Various Small Molecules ▿

PubMed Central

Shareck, Julie; Belhumeur, Pierre

2011-01-01

The pathogenic yeast Candida albicans, a member of the mucosal microbiota, is responsible for a large spectrum of infections, ranging from benign thrush and vulvovaginitis in both healthy and immunocompromised individuals to severe, life-threatening infections in immunocompromised patients. A striking feature of C. albicans is its ability to grow as budding yeast and as filamentous forms, including hyphae and pseudohyphae. The yeast-to-hypha transition contributes to the overall virulence of C. albicans and may even constitute a target for the development of antifungal drugs. Indeed, impairing morphogenesis in C. albicans has been shown to be a means to treat candidiasis. Additionally, a large number of small molecules such as farnesol, fatty acids, rapamycin, geldanamycin, histone deacetylase inhibitors, and cell cycle inhibitors have been reported to modulate the yeast-to-hypha transition in C. albicans. In this minireview, we take a look at molecules that modulate morphogenesis in this pathogenic yeast. When possible, we address experimental findings regarding their mechanisms of action and their therapeutic potential. We discuss whether or not modulating morphogenesis constitutes a strategy to treat Candida infections. PMID:21642508

Superficial mycotic infections of the foot in a native pediatric population: a pathogenic role for Trichosporon cutaneum?

PubMed

Archer-Dubon, Carla; Orozco-Topete, Rocío; Leyva-Santiago, Jaime; Arenas, Roberto; Carbajosa, Josefina; Ysunza, Alberto

2003-01-01

Superficial mycotic infections of the feet are usually caused by Tricophyton rubrum, predominantly affecting adults and resulting from the use of occlusive footwear. We carried out a mycologic study of superficial foot infections in a rural school in Mexico where most people wear a leather, nonocclusive sandal. Forty students had clinical signs of 50 fungal infections of the foot: 39 athlete's foot and 11 onychomycosis. Thirty-one boys and 9 girls were studied. Hyphae were seen in 11 cases of athlete's foot and 5 of onychomycosis. Twenty-one cultures were positive (42%). The most frequently isolated fungi were the opportunistic Trichosporon cutaneum in 42.8%, Candida sp. (23.8%), Trichophyton mentagrophytes (23.8%), and Candida glabrata (9.5%). Superficial mycotic infections of the feet and nails were most frequent in children and adolescents who usually wear nonocclusive shoes. The most frequent pathogens were Candida sp. and T. mentagrophytes. It is interesting to note the prevalence of T. cutaneum that has recently been implicated in mycoses of the feet and nails. We did not isolate T. rubrum in any patient.

Immunological relatedness among Candida albicans and other pathogenic Candida species.

PubMed Central

Hector, R F; Lyon, F L; Domer, J E

1981-01-01

Membrane-mitochondrial (butanol-hot phosphate-buffered saline) and cytosol (soluble cytoplasmic substances) extracts from seven pathogenic species of Candida were used in in vivo and in vitro immunological assays to study antigenic similarities among the strains with respect to C. albicans. Mice were sensitized with C. albicans serotype A for footpad testing or to provide cells for lymphocyte stimulation assays, and guinea pigs were immunized with whole cells or butanol-hot phosphate-buffered saline extracts of C. albicans to obtain antisera for immunodiffusion assays. When extracts from each of the seven species were used in the assays, they consistently segregated, as determined by statistical or subjective analyses, into three groups. Extracts of C. albicans serotype A or B and C. stellatoidea were the most immunologically reactive in all assays, indicating close similarities between those two species, whereas extracts of C. tropicalis and C. parapsilosis elicited only moderate responses. Extracts from C. krusei, C. guilliermondii, and C. pseudotropicalis were hypo- or nonreactive in the assays, indicating a low level of antigenic relatedness to C. albicans. Images PMID:7037643

Evaluation of Microbial Load in Oropharyngeal Mucosa from Tannery Workers

PubMed Central

Castellanos-Arévalo, Diana C.; Castellanos-Arévalo, Andrea P.; Camarena-Pozos, David A.; Colli-Mull, Juan G.; Maldonado-Vega, María

2014-01-01

Background Animal skin provides an ideal medium for the propagation of microorganisms and it is used like raw material in the tannery and footware industry. The aim of this study was to evaluate and identify the microbial load in oropharyngeal mucosa of tannery employees. Methods The health risk was estimated based on the identification of microorganisms found in the oropharyngeal mucosa samples. The study was conducted in a tanners group and a control group. Samples were taken from oropharyngeal mucosa and inoculated on plates with selective medium. In the samples, bacteria were identified by 16S ribosomal DNA analysis and the yeasts through a presumptive method. In addition, the sensitivity of these microorganisms to antibiotics/antifungals was evaluated. Results The identified bacteria belonged to the families Enterobacteriaceae, Pseudomonadaceae, Neisseriaceae, Alcaligenaceae, Moraxellaceae, and Xanthomonadaceae, of which some species are considered as pathogenic or opportunistic microorganisms; these bacteria were not present in the control group. Forty-two percent of bacteria identified in the tanners group are correlated with respiratory diseases. Yeasts were also identified, including the following species: Candida glabrata, Candida tropicalis, Candida albicans, and Candida krusei. Regarding the sensitivity test of bacteria identified in the tanners group, 90% showed sensitivity to piperacillin/tazobactam, 87% showed sensitivity to ticarcillin/clavulanic acid, 74% showed sensitivity to ampicillin/sulbactam, and 58% showed sensitivity to amoxicillin/clavulanic acid. Conclusion Several of the bacteria and yeast identified in the oropharyngeal mucosa of tanners have been correlated with infections in humans and have already been reported as airborne microorganisms in this working environment, representing a health risk for workers. PMID:25830072

MALDI-TOF mass spectrometry proteomic phenotyping of clinically relevant fungi.

PubMed

Putignani, Lorenza; Del Chierico, Federica; Onori, Manuela; Mancinelli, Livia; Argentieri, Marta; Bernaschi, Paola; Coltella, Luana; Lucignano, Barbara; Pansani, Laura; Ranno, Stefania; Russo, Cristina; Urbani, Andrea; Federici, Giorgio; Menichella, Donato

2011-03-01

Proteomics is particularly suitable for characterising human pathogens with high life cycle complexity, such as fungi. Protein content and expression levels may be affected by growth states and life cycle morphs and correlate to species and strain variation. Identification and typing of fungi by conventional methods are often difficult, time-consuming and frequently, for unusual species, inconclusive. Proteomic phenotypes from MALDI-TOF MS were employed as analytical and typing expression profiling of yeast, yeast-like species and strain variants in order to achieve a microbial proteomics population study. Spectra from 303 clinical isolates were generated and processed by standard pattern matching with a MALDI-TOF Biotyper (MT). Identifications (IDs) were compared to a reference biochemical-based system (Vitek-2) and, when discordant, MT IDs were verified with genotyping IDs, obtained by sequencing the 25-28S rRNA hypervariable D2 region. Spectra were converted into virtual gel-like formats, and hierarchical clustering analysis was performed for 274 Candida profiles to investigate species and strain typing correlation. MT provided 257/303 IDs consistent with Vitek-2 ones. However, amongst 26/303 discordant MT IDs, only 5 appeared "true". No MT identification was achieved for 20/303 isolates for incompleteness of database species variants. Candida spectra clustering agreed with identified species and topology of Candida albicans and Candida parapsilosis specific dendrograms. MT IDs show a high analytical performance and profiling heterogeneity which seems to complement or even outclass existing typing tools. This variability reflects the high biological complexity of yeasts and may be properly exploited to provide epidemiological tracing and infection dispersion patterns.

In vitro antimicrobial activity of Caesalpinia ferrea Martius fruits against oral pathogens.

PubMed

Sampaio, Fábio C; Pereira, Maria do Socorro V; Dias, Celidarque S; Costa, Vicente Carlos O; Conde, Nikeila C O; Buzalaf, Marília A R

2009-07-15

In the Amazon region of Brazil, the fruits of Caesalpinia ferrea Martius (Brazilian ironwood) are widely used as an antimicrobial and healing medicine in many situations including oral infections. This study aimed to evaluate the antimicrobial activity of Caesalpinia ferrea Martius fruit extract against oral pathogens. Polyphenols estimation and spectral analysis ((1)H NMR) of the methanol extract were carried out. The microorganisms Candida albicans, Streptococcus mutans, Streptococcus salivarius, Streptococcus oralis and Lactobacillus casei were tested using the microdilution method for planktonic cells (MIC) and a multispecies biofilm model. Chlorhexidine was used as positive control. Polyphenols in the extract were estimated at 7.3% and (1)H NMR analysis revealed hydroxy phenols and methoxilated compounds. MIC values for Candida albicans, Streptococcus mutans, Streptococcus salivarius, Streptococcus oralis and Lactobacillus casei were 25.0, 40.0, 66.0, 100.0, 66.0 microg/mL, respectively. For the biofilm assay, chlorhexidine and plant extract showed no growth at 10(-4) and 10(-5) microbial dilution, respectively. At 10(-4) and 10(-5) the growth values (mean+/-SD) of the negative controls (DMSO and saline solution) for Streptococcus mutans, Streptococcus sp. and Candida albicans were 8.1+/-0.7, 7.0+/-0.6 and 5.9+/-0.9 x 10(6)CFU, respectively. Caesalpinia ferrea fruit extract can inhibit in vitro growth of oral pathogens in planktonic and biofilm models supporting its use for oral infections.

Antibody to a conserved antigenic target is protective against diverse prokaryotic and eukaryotic pathogens

PubMed Central

Cywes-Bentley, Colette; Skurnik, David; Zaidi, Tanweer; Roux, Damien; DeOliveira, Rosane B.; Garrett, Wendy S.; Lu, Xi; O’Malley, Jennifer; Kinzel, Kathryn; Zaidi, Tauqeer; Rey, Astrid; Perrin, Christophe; Fichorova, Raina N.; Kayatani, Alexander K. K.; Maira-Litràn, Tomas; Gening, Marina L.; Tsvetkov, Yury E.; Nifantiev, Nikolay E.; Bakaletz, Lauren O.; Pelton, Stephen I.; Golenbock, Douglas T.; Pier, Gerald B.

2013-01-01

Microbial capsular antigens are effective vaccines but are chemically and immunologically diverse, resulting in a major barrier to their use against multiple pathogens. A β-(1→6)–linked poly-N-acetyl-d-glucosamine (PNAG) surface capsule is synthesized by four proteins encoded in genetic loci designated intercellular adhesion in Staphylococcus aureus or polyglucosamine in selected Gram-negative bacterial pathogens. We report that many microbial pathogens lacking an identifiable intercellular adhesion or polyglucosamine locus produce PNAG, including Gram-positive, Gram-negative, and fungal pathogens, as well as protozoa, e.g., Trichomonas vaginalis, Plasmodium berghei, and sporozoites and blood-stage forms of Plasmodium falciparum. Natural antibody to PNAG is common in humans and animals and binds primarily to the highly acetylated glycoform of PNAG but is not protective against infection due to lack of deposition of complement opsonins. Polyclonal animal antibody raised to deacetylated glycoforms of PNAG and a fully human IgG1 monoclonal antibody that both bind to native and deacetylated glycoforms of PNAG mediated complement-dependent opsonic or bactericidal killing and protected mice against local and/or systemic infections by Streptococcus pyogenes, Streptococcus pneumoniae, Listeria monocytogenes, Neisseria meningitidis serogroup B, Candida albicans, and P. berghei ANKA, and against colonic pathology in a model of infectious colitis. PNAG is also a capsular polysaccharide for Neisseria gonorrhoeae and nontypable Hemophilus influenzae, and protects cells from environmental stress. Vaccination targeting PNAG could contribute to immunity against serious and diverse prokaryotic and eukaryotic pathogens, and the conserved production of PNAG suggests that it is a critical factor in microbial biology. PMID:23716675

Inhibitory effect of chromogenic culture media on the growth of Rhodotorula: relevance to the diagnosis of Rhodotorula spp. infections.

PubMed

Bellanger, Anne-Pauline; Grenouillet, Frédéric; François, Nadine; Skana, Florence; Millon, Laurence

2013-11-01

With the increasing incidence and diverse etiologies of fungal infections, chromogenic yeast culture media are increasingly used for routine diagnosis. Rhodotorula species, which are characterized by the production of carotenoid pigments, are considered as emerging opportunistic pathogens. We recently diagnosed two fungemia due to Rhodotorula spp. and noticed that in both cases, the yeast failed to grow in subculture on the chromogenic yeast culture medium. This study was thus undertaken to investigate more thoroughly the ability (or inability) of Rhodotorula species to grow on different commercially available chromogenic media for yeast. Eighteen Rhodotorula spp. were checked for their ability to grow on four chromogenic yeast culture media: CHROMagar Candida (BD), Candi 4 Select (Biorad), Brilliance Candida (Oxoid), and Candida ID 2 (BioMerieux). All the Rhodotorula spp. strains grew on Brilliance and Candida ID 2, while only six isolates grew on Candi 4, and seven on CHROMagar. Two chromogenic yeast culture media showed a significant inhibitory effect on the growth of Rhodotorula species. As all Rhodotorula species are resistant to echinocandins and fluconazole, it is essential to isolate and identify these yeast quickly to initiate appropriate amphotericin B antifungal treatment as early as possible. The choice of media for routine use should take into account the ability of different media to allow all emerging fungal pathogens to grow. © 2013 APMIS. Published by John Wiley & Sons Ltd.

Synergistic combinations of antifungals and anti-virulence agents to fight against Candida albicans.

PubMed

Cui, Jinhui; Ren, Biao; Tong, Yaojun; Dai, Huanqin; Zhang, Lixin

2015-01-01

Candida albicans, one of the pathogenic Candida species, causes high mortality rate in immunocompromised and high-risk surgical patients. In the last decade, only one new class of antifungal drug echinocandin was applied. The increased therapy failures, such as the one caused by multi-drug resistance, demand innovative strategies for new effective antifungal drugs. Synergistic combinations of antifungals and anti-virulence agents highlight the pragmatic strategy to reduce the development of drug resistant and potentially repurpose known antifungals, which bypass the costly and time-consuming pipeline of new drug development. Anti-virulence and synergistic combination provide new options for antifungal drug discovery by counteracting the difficulty or failure of traditional therapy for fungal infections.

Seasonal variation of the upper digestive tract yeast flora of feral pigeons

USGS Publications Warehouse

Kocan, R.M.; Hasenclever, H.F.

1974-01-01

Feral pigeons were sampled over a 16-month period to determine whether their normal yeast flora varied according to season. Candida albicans and Saccharomyces telluris occurred during the entire sampling period, with C. albicans reaching its highest levels between August and January and S. telluris peaking from March through May. Candida krusei was present for 10 months but exhibited no predictable variation in density. Candida tropicalis, C. guilliermondii and Geotrichum were isolated on several occasions while C. lusitaniae, C. pseudotropicalis and Torulopsis glabrata were each isolated once. The high levels of infection and frequency of occurrence of some yeast species make the feral pigeon highly suspect as a carrier and disseminator of potentially pathogenic yeast.

Miltefosine inhibits Candida albicans and non-albicans Candida spp. biofilms and impairs the dispersion of infectious cells.

PubMed

Vila, Taissa; Ishida, Kelly; Seabra, Sergio Henrique; Rozental, Sonia

2016-11-01

Candida spp. can adhere to and form biofilms over different surfaces, becoming less susceptible to antifungal treatment. Resistance of biofilms to antifungal agents is multifactorial and the extracellular matrix (ECM) appears to play an important role. Among the few available antifungals for treatment of candidaemia, only the lipid formulations of amphotericin B (AmB) and the echinocandins are effective against biofilms. Our group has previously demonstrated that miltefosine has an important effect against Candida albicans biofilms. Thus, the aim of this work was to expand the analyses of the in vitro antibiofilm activity of miltefosine to non-albicans Candida spp. Miltefosine had significant antifungal activity against planktonic cells and the development of biofilms of C. albicans, Candida parapsilosis, Candida tropicalis and Candida glabrata. The activity profile in biofilms was superior to fluconazole and was similar to that of AmB and caspofungin. Biofilm-derived cells with their ECM extracted became as susceptible to miltefosine as planktonic cells, confirming the importance of the ECM in the biofilm resistant behaviour. Miltefosine also inhibited biofilm dispersion of cells at the same concentration needed to inhibit planktonic cell growth. The data obtained in this work reinforce the potent inhibitory activity of miltefosine on biofilms of the four most pathogenic Candida spp. and encourage further studies for the utilisation of this drug and/or structural analogues on biofilm-related infections. Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

Distribution and Drug Susceptibility of Candida spp. Associated With Female Genital Tract Infection, Chongqing, China

PubMed Central

Luo, Xiaodong; Dong, Xiaojing; Pen, Zhi

2015-01-01

Background Vulvovaginal candidiasis is defined as vulvovaginitis associated with vaginal carriage of Candida spp. and is a common problem with a high rate of morbidity. Objectives To investigate the distribution of Candida spp. and evaluate the corresponding antifungal susceptibility in women with genital tract infection in Chongqing, southwestern China. Patients and Methods Samples (n = 2.129) were obtained from female patients with symptoms of genital tract infection. Candida spp. were isolated from the specimens and were identified using a coloration medium and the VITEK 2 Compact automatic microbial identification system. Antifungal susceptibility testing was performed using the ATB FUNGUS drug susceptibility testing system. Results From 2,129 samples, 478 (22.45%) isolates of Candida were isolated, of which 395 (82.64%) were Candida albicans, 39 (8.16%) were C. glabrata, 21 (4.39%) were C. tropicalis, 9 (1.88%) were C. parapsilosis, and 14 (2.93%) were other Candida spp. The resistance of C. albicans, C. glabrata, and C. tropicalis to 5 antifungal drugs (amphotericin B, voriconazole, fluconazole, 5-fluorocytosine, and itraconazole) ranged from 0.5% to 6.4%, 0% to 7.7%, and 0% to 9.6%, respectively. Conclusions Candida albicans was the major pathogen associated with candidiasis of the female genital tract in patients in Chongqing. The results of the antifungal sensitivity of the isolates suggest that it is important for clinicians to administer appropriate antifungals for the treatment of Candida spp. infections. PMID:28138369

Thailandins A and B, New Polyene Macrolactone Compounds Isolated from Actinokineospora bangkokensis Strain 44EHW(T), Possessing Antifungal Activity against Anthracnose Fungi and Pathogenic Yeasts.

PubMed

Intra, Bungonsiri; Greule, Anja; Bechthold, Andreas; Euanorasetr, Jirayut; Paululat, Thomas; Panbangred, Watanalai

2016-06-29

Two new polyene macrolactone antibiotics, thailandins A, 1, and B, 2, were isolated from the fermentation broth of rhizosphere soil-associated Actinokineospora bangkokensis strain 44EHW(T). The new compounds from this strain were purified using semipreparative HPLC and Sephadex LH-20 gel filtration while following an antifungal activity guided fractionation. Their structures were elucidated through spectroscopic techniques including UV, HR-ESI-MS, and NMR. These compounds demonstrated broad spectrum antifungal activity against fungi causing anthracnose disease (Colletotrichum gloeosporioides DoA d0762, Colletotrichum gloeosporiodes DoA c1060, and Colletotrichum capsici DoA c1511) as well as pathogenic yeasts (Candida albicans MT 2013/1, Candida parasilopsis DKMU 434, and Cryptococcus neoformans MT 2013/2) with minimum inhibitory concentrations ranging between 16 and 32 μg/mL. This is the first report of polyene antibiotics produced by Actinokineospora species as bioactive compounds against anthracnose fungi and pathogenic yeast strains.

The Candida albicans Hwp2p can complement the lack of filamentation of a Saccharomyces cerevisiae flo11 null strain.

PubMed

Younes, Samer S; Khalaf, Roy A

2013-06-01

The opportunistic fungal pathogen Candida albicans is one of the leading agents of life-threatening infections affecting immunocompromised individuals. Many factors make C. albicans a successful pathogen. These include the ability to switch between yeast and invasive hyphal morphologies in addition to an arsenal of cell wall virulence factors such as lipases, proteases, dismutases and adhesins that promote the attachment to the host, a prerequisite for invasive growth. We have previously characterized Hwp2, a C. albicans cell wall protein which we found necessary for proper oxidative stress, biofilm formation and adhesion to host cells. Baker's yeast Saccharomyces cerevisiae also possesses adhesins that promote aggregation and flocculence. Flo11 is one such adhesin that has sequence similarity to Hwp2. Here we determined that transforming an HWP2 cassette can complement the lack of filamentation of an S. cerevisiae flo11 null strain and impart on S. cerevisiae adhesive properties similar to those of a pathogen.

SNF3 as High Affinity Glucose Sensor and Its Function in Supporting the Viability of Candida glabrata under Glucose-Limited Environment.

PubMed

Ng, Tzu Shan; Chew, Shu Yih; Rangasamy, Premmala; Mohd Desa, Mohd N; Sandai, Doblin; Chong, Pei Pei; Than, Leslie Thian Lung

2015-01-01

Candida glabrata is an emerging human fungal pathogen that has efficacious nutrient sensing and responsiveness ability. It can be seen through its ability to thrive in diverse range of nutrient limited-human anatomical sites. Therefore, nutrient sensing particularly glucose sensing is thought to be crucial in contributing to the development and fitness of the pathogen. This study aimed to elucidate the role of SNF3 (Sucrose Non Fermenting 3) as a glucose sensor and its possible role in contributing to the fitness and survivability of C. glabrata in glucose-limited environment. The SNF3 knockout strain was constructed and subjected to different glucose concentrations to evaluate its growth, biofilm formation, amphotericin B susceptibility, ex vivo survivability and effects on the transcriptional profiling of the sugar receptor repressor (SRR) pathway-related genes. The CgSNF3Δ strain showed a retarded growth in low glucose environments (0.01 and 0.1%) in both fermentation and respiration-preferred conditions but grew well in high glucose concentration environments (1 and 2%). It was also found to be more susceptible to amphotericin B in low glucose environment (0.1%) and macrophage engulfment but showed no difference in the biofilm formation capability. The deletion of SNF3 also resulted in the down-regulation of about half of hexose transporters genes (four out of nine). Overall, the deletion of SNF3 causes significant reduction in the ability of C. glabrata to sense limited surrounding glucose and consequently disrupts its competency to transport and perform the uptake of this critical nutrient. This study highlighted the role of SNF3 as a high affinity glucose sensor and its role in aiding the survivability of C. glabrata particularly in glucose limited environment.

Effective killing of the human pathogen Candida albicans by a specific inhibitor of non-essential mitotic kinesin Kip1p

PubMed Central

Chua, Penelope R; Roof, David M; Lee, Yan; Sakowicz, Roman; Clarke, David; Pierce, Dan; Stephens, Thoryn; Hamilton, Matthew; Morgan, Brad; Morgans, David; Nakai, Takashi; Tomasi, Adam; Maxon, Mary E

2007-01-01

Kinesins from the bipolar (Kinesin-5) family are conserved in eukaryotic organisms and play critical roles during the earliest stages of mitosis to mediate spindle pole body separation and formation of a bipolar mitotic spindle. To date, genes encoding bipolar kinesins have been reported to be essential in all organisms studied. We report the characterization of CaKip1p, the sole member of this family in the human pathogenic yeast Candida albicans. C. albicans Kip1p appears to localize to the mitotic spindle and loss of CaKip1p function interferes with normal progression through mitosis. Inducible excision of CaKIP1 revealed phenotypes unique to C. albicans, including viable homozygous Cakip1 mutants and an aberrant spindle morphology in which multiple spindle poles accumulate in close proximity to each other. Expression of the C. albicans Kip1 motor domain in Escherichia coli produced a protein with microtubule-stimulated ATPase activity that was inhibited by an aminobenzothiazole (ABT) compound in an ATP-competitive fashion. This inhibition results in ‘rigor-like’, tight association with microtubules in vitro. Upon treatment of C. albicans cells with the ABT compound, cells were killed, and terminal phenotype analysis revealed an aberrant spindle morphology similar to that induced by loss of the CaKIP1 gene. The ABT compound discovered is the first example of a fungal spindle inhibitor targeted to a mitotic kinesin. Our results also show that the non-essential nature and implementation of the bipolar motor in C. albicans differs from that seen in other organisms, and suggest that inhibitors of a non-essential mitotic kinesin may offer promise as cidal agents for antifungal drug discovery. PMID:17573815

Melanocytes and melanin represent a first line of innate immunity against Candida albicans.

PubMed

Tapia, Cecilia V; Falconer, Maryanne; Tempio, Fabián; Falcón, Felipe; López, Mercedes; Fuentes, Marisol; Alburquenque, Claudio; Amaro, José; Bucarey, Sergio A; Di Nardo, Anna

2014-07-01

Melanocytes are dendritic cells located in the skin and mucosae that synthesize melanin. Some infections induce hypo- or hyperpigmentation, which is associated with the activation of Toll-like receptors (TLRs), especially TLR4. Candida albicans is an opportunist pathogen that can switch between blastoconidia and hyphae forms; the latter is associated with invasion. Our objectives in this study were to ascertain whether C. albicans induces pigmentation in melanocytes and whether this process is dependent on TLR activation, as well as relating this with the antifungal activity of melanin as a first line of innate immunity against fungal infections. Normal human melanocytes were stimulated with C. albicans supernatants or with crude extracts of the blastoconidia or hyphae forms, and pigmentation and TLR2/TLR4 expression were measured. Expression of the melanosomal antigens Melan-A and gp100 was examined for any correlation with increased melanin levels or antifungal activity in melanocyte lysates. Melanosomal antigens were induced earlier than cell pigmentation, and hyphae induced stronger melanization than blastoconidia. Notably, when melanocytes were stimulated with crude extracts of C. albicans, the cell surface expression of TLR2/TLR4 began at 48 h post-stimulation and peaked at 72 h. At this time, blastoconidia induced both TLR2 and TLR4 expression, whereas hyphae only induced TLR4 expression. Taken together, these results suggest that melanocytes play a key role in innate immune responses against C. albicans infections by recognizing pathogenic forms of C. albicans via TLR4, resulting in increased melanin content and inhibition of infection. © The Author 2014. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Fungicidal efficacy of various honeys against fluconazole-resistant Candida species isolated from HIV+ patients with candidiasis.

PubMed

Shokri, H; Sharifzadeh, A

2017-06-01

Honey is well known to possess a broad spectrum of activity against medically important organisms. The purpose of this study was to assess the antifungal activity of different honeys against 40 fluconazole (FLU) resistant Candida species, including Candida albicans (C. albicans), Candida glabrata, Candida krusei and Candida tropicalis. Three honey samples were collected from northern (Mazandaran, A), southern (Hormozgan, B) and central (Lorestan, C) regions of Iran. A microdilution technique based on the CLSI, M27-A2 protocol was employed to compare the susceptibility of honeys "A", "B" and "C" against different pathogenic Candida isolates. The results showed that different Candida isolates were resistant to FLU, ranging from 64μg/mL to 512μg/mL. All of the honeys tested had antifungal activities against FLU-resistant Candida species, ranging from 20% to 56.25% (v/v) and 25% to 56.25% (v/v) for minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs), respectively. Honey "A" (MIC: 31.59%, v/v) showed higher anti-Candida activity than honey "B" (MIC: 35.99%, v/v) and honey "C" (MIC: 39.2%, v/v). No statistically significant differences were observed among the mean MIC values of the honey samples (P>0.05). The order of overall susceptibility of Candida species to honey samples were; C. krusei>C. glabrata>C. tropicalis>C. albicans (P>0.05). In addition, the mean MICs of Candida strains isolated from the nail, vagina and oral cavity were 33.68%, 36.44% and 39.89%, respectively, and were not significantly different (P>0.05). Overall, varying susceptibilities to the anti-Candida properties of different honeys were observed with four FLU-resistant species of Candida. Further research is needed to assess the efficacy of honey as an inhibitor of candidal growth in clinical trials. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Evaluation of Novel Broad-Range Real-Time PCR Assay for Rapid Detection of Human Pathogenic Fungi in Various Clinical Specimens▿

PubMed Central

Vollmer, Tanja; Störmer, Melanie; Kleesiek, Knut; Dreier, Jens

2008-01-01

In the present study, a novel broad-range real-time PCR was developed for the rapid detection of human pathogenic fungi. The assay targets a part of the 28S large-subunit ribosomal RNA (rDNA) gene. We investigated its application for the most important human pathogenic fungal genera, including Aspergillus, Candida, Cryptococcus, Mucor, Penicillium, Pichia, Microsporum, Trichophyton, and Scopulariopsis. Species were identified in PCR-positive reactions by direct DNA sequencing. A noncompetitive internal control was applied to prevent false-negative results due to PCR inhibition. The minimum detection limit for the PCR was determined to be one 28S rDNA copy per PCR, and the 95% detection limit was calculated to 15 copies per PCR. To assess the clinical applicability of the PCR method, intensive-care patients with artificial respiration and patients with infective endocarditis were investigated. For this purpose, 76 tracheal secretion samples and 70 heart valve tissues were analyzed in parallel by real-time PCR and cultivation. No discrepancies in results were observed between PCR analysis and cultivation methods. Furthermore, the application of the PCR method was investigated for other clinical specimens, including cervical swabs, nail and horny skin scrapings, and serum, blood, and urine samples. The combination of a broad-range real-time PCR and direct sequencing facilitates rapid screening for fungal infection in various clinical specimens. PMID:18385440

Evaluation of novel broad-range real-time PCR assay for rapid detection of human pathogenic fungi in various clinical specimens.

PubMed

Vollmer, Tanja; Störmer, Melanie; Kleesiek, Knut; Dreier, Jens

2008-06-01

In the present study, a novel broad-range real-time PCR was developed for the rapid detection of human pathogenic fungi. The assay targets a part of the 28S large-subunit ribosomal RNA (rDNA) gene. We investigated its application for the most important human pathogenic fungal genera, including Aspergillus, Candida, Cryptococcus, Mucor, Penicillium, Pichia, Microsporum, Trichophyton, and Scopulariopsis. Species were identified in PCR-positive reactions by direct DNA sequencing. A noncompetitive internal control was applied to prevent false-negative results due to PCR inhibition. The minimum detection limit for the PCR was determined to be one 28S rDNA copy per PCR, and the 95% detection limit was calculated to 15 copies per PCR. To assess the clinical applicability of the PCR method, intensive-care patients with artificial respiration and patients with infective endocarditis were investigated. For this purpose, 76 tracheal secretion samples and 70 heart valve tissues were analyzed in parallel by real-time PCR and cultivation. No discrepancies in results were observed between PCR analysis and cultivation methods. Furthermore, the application of the PCR method was investigated for other clinical specimens, including cervical swabs, nail and horny skin scrapings, and serum, blood, and urine samples. The combination of a broad-range real-time PCR and direct sequencing facilitates rapid screening for fungal infection in various clinical specimens.

Tracking the emerging human pathogen Pseudallescheria boydii by using highly specific monoclonal antibodies.

PubMed

Thornton, Christopher R

2009-05-01

Pseudallescheria boydii has long been known to cause white grain mycetoma in immunocompetent humans, but it has recently emerged as an opportunistic pathogen of humans, causing potentially fatal invasive infections in immunocompromised individuals and evacuees of natural disasters, such as tsunamis and hurricanes. The diagnosis of P. boydii is problematic since it exhibits morphological characteristics similar to those of other hyaline fungi that cause infectious diseases, such as Aspergillus fumigatus and Scedosporium prolificans. This paper describes the development of immunoglobulin M (IgM) and IgG1 kappa-light chain monoclonal antibodies (MAbs) specific to P. boydii and certain closely related fungi. The MAbs bind to an immunodominant carbohydrate epitope on an extracellular 120-kDa antigen present in the spore and hyphal cell walls of P. boydii and Scedosporium apiospermum. The MAbs do not react with S. prolificans, Scedosporium dehoogii, or a large number of clinically relevant fungi, including A. fumigatus, Candida albicans, Cryptococcus neoformans, Fusarium solani, and Rhizopus oryzae. The MAbs were used in immunofluorescence and double-antibody sandwich enzyme-linked immunosorbent assays (DAS-ELISAs) to accurately differentiate P. boydii from other infectious fungi and to track the pathogen in environmental samples. Specificity of the DAS-ELISA was confirmed by sequencing of the internally transcribed spacer 1 (ITS1)-5.8S-ITS2 rRNA-encoding regions of environmental isolates.

Characterisation of Candida within the Mycobiome/Microbiome of the Lower Respiratory Tract of ICU Patients

PubMed Central

Krause, Robert; Halwachs, Bettina; Thallinger, Gerhard G.; Klymiuk, Ingeborg; Gorkiewicz, Gregor; Hoenigl, Martin; Prattes, Jürgen; Valentin, Thomas; Heidrich, Katharina; Buzina, Walter; Salzer, Helmut J. F.; Rabensteiner, Jasmin; Prüller, Florian; Raggam, Reinhard B.; Meinitzer, Andreas; Moissl-Eichinger, Christine; Högenauer, Christoph; Quehenberger, Franz; Kashofer, Karl; Zollner-Schwetz, Ines

2016-01-01

Whether the presence of Candida spp. in lower respiratory tract (LRT) secretions is a marker of underlying disease, intensive care unit (ICU) treatment and antibiotic therapy or contributes to poor clinical outcome is unclear. We investigated healthy controls, patients with proposed risk factors for Candida growth in LRT (antibiotic therapy, ICU treatment with and without antibiotic therapy), ICU patients with pneumonia and antibiotic therapy and candidemic patients (for comparison of truly invasive and colonizing Candida spp.). Fungal patterns were determined by conventional culture based microbiology combined with molecular approaches (next generation sequencing, multilocus sequence typing) for description of fungal and concommitant bacterial microbiota in LRT, and host and fungal biomarkes were investigated. Admission to and treatment on ICUs shifted LRT fungal microbiota to Candida spp. dominated fungal profiles but antibiotic therapy did not. Compared to controls, Candida was part of fungal microbiota in LRT of ICU patients without pneumonia with and without antibiotic therapy (63% and 50% of total fungal genera) and of ICU patients with pneumonia with antibiotic therapy (73%) (p<0.05). No case of invasive candidiasis originating from Candida in the LRT was detected. There was no common bacterial microbiota profile associated or dissociated with Candida spp. in LRT. Colonizing and invasive Candida strains (from candidemic patients) did not match to certain clades withdrawing the presence of a particular pathogenic and invasive clade. The presence of Candida spp. in the LRT rather reflected rapidly occurring LRT dysbiosis driven by ICU related factors than was associated with invasive candidiasis. PMID:27206014

Epithelial invasion outcompetes hypha development during Candida albicans infection as revealed by an image-based systems biology approach.

PubMed

Mech, Franziska; Wilson, Duncan; Lehnert, Teresa; Hube, Bernhard; Thilo Figge, Marc

2014-02-01

Candida albicans is the most common opportunistic fungal pathogen of the human mucosal flora, frequently causing infections. The fungus is responsible for invasive infections in immunocompromised patients that can lead to sepsis. The yeast to hypha transition and invasion of host-tissue represent major determinants in the switch from benign colonizer to invasive pathogen. A comprehensive understanding of the infection process requires analyses at the quantitative level. Utilizing fluorescence microscopy with differential staining, we obtained images of C. albicans undergoing epithelial invasion during a time course of 6 h. An image-based systems biology approach, combining image analysis and mathematical modeling, was applied to quantify the kinetics of hyphae development, hyphal elongation, and epithelial invasion. The automated image analysis facilitates high-throughput screening and provided quantities that allow for the time-resolved characterization of the morphological and invasive state of fungal cells. The interpretation of these data was supported by two mathematical models, a kinetic growth model and a kinetic transition model, that were developed using differential equations. The kinetic growth model describes the increase in hyphal length and revealed that hyphae undergo mass invasion of epithelial cells following primary hypha formation. We also provide evidence that epithelial cells stimulate the production of secondary hyphae by C. albicans. Based on the kinetic transition model, the route of invasion was quantified in the state space of non-invasive and invasive fungal cells depending on their number of hyphae. This analysis revealed that the initiation of hyphae formation represents an ultimate commitment to invasive growth and suggests that in vivo, the yeast to hypha transition must be under exquisitely tight negative regulation to avoid the transition from commensal to pathogen invading the epithelium. © 2013 International Society for Advancement of Cytometry.

Ybp1 and Gpx3 signaling in Candida albicans govern hydrogen peroxide-induced oxidation of the Cap1 transcription factor and macrophage escape.

PubMed

Patterson, Miranda J; McKenzie, Christopher G; Smith, Deborah A; da Silva Dantas, Alessandra; Sherston, Sam; Veal, Elizabeth A; Morgan, Brian A; MacCallum, Donna M; Erwig, Lars-Peter; Quinn, Janet

2013-12-20

As Candida albicans is the major fungal pathogen of humans, there is an urgent need to understand how this pathogen evades toxic reactive oxygen species (ROS) generated by the host immune system. A key regulator of antioxidant gene expression, and thus ROS resistance, in C. albicans is the AP-1-like transcription factor Cap1. Despite this, little is known regarding the intracellular signaling mechanisms that underlie the oxidation and activation of Cap1. Therefore, the aims of this study were; (i) to identify the regulatory proteins that govern Cap1 oxidation, and (ii) to investigate the importance of Cap1 oxidation in C. albicans pathogenesis. In response to hydrogen peroxide (H2O2), but not glutathione-depleting/modifying oxidants, Cap1 oxidation, nuclear accumulation, phosphorylation, and Cap1-dependent gene expression, is mediated by a glutathione peroxidase-like enzyme, which we name Gpx3, and an orthologue of the Saccharomyces cerevisiae Yap1 binding protein, Ybp1. In addition, Ybp1 also functions to stabilise Cap1 and this novel function is conserved in S. cerevisiae. C. albicans cells lacking Cap1, Ybp1, or Gpx3, are unable to filament and thus, escape from murine macrophages after phagocytosis, and also display defective virulence in the Galleria mellonella infection model. Ybp1 is required to promote the stability of fungal AP-1-like transcription factors, and Ybp1 and Gpx3 mediated Cap1-dependent oxidative stress responses are essential for the effective killing of macrophages by C. albicans. Activation of Cap1, specifically by H2O2, is a prerequisite for the subsequent filamentation and escape of this fungal pathogen from the macrophage.

Genetic susceptibility to Candida infections

PubMed Central

Smeekens, Sanne P; van de Veerdonk, Frank L; Kullberg, Bart Jan; Netea, Mihai G

2013-01-01

Candida spp. are medically important fungi causing severe mucosal and life-threatening invasive infections, especially in immunocompromised hosts. However, not all individuals at risk develop Candida infections, and it is believed that genetic variation plays an important role in host susceptibility. On the one hand, severe fungal infections are associated with monogenic primary immunodeficiencies such as defects in STAT1, STAT3 or CARD9, recently discovered as novel clinical entities. On the other hand, more common polymorphisms in genes of the immune system have also been associated with fungal infections such as recurrent vulvovaginal candidiasis and candidemia. The discovery of the genetic susceptibility to Candida infections can lead to a better understanding of the pathogenesis of the disease, as well as to the design of novel immunotherapeutic strategies. This review is part of the review series on host-pathogen interactions. See more reviews from this series. PMID:23629947

Neutrophil-mediated protection of cultured human vascular endothelial cells from damage by growing Candida albicans hyphae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwards, J.E. Jr.; Rotrosen, D.; Fontaine, J.W.

1987-05-01

Interactions were studied between human neutrophils and cultured human umbilical vein endothelial cells invaded by Candida albicans. In the absence of neutrophils, progressive Candida germination and hyphal growth extensively damaged endothelial cell monolayers over a period of 4 to 6 hours, as determined both by morphological changes and release of /sup 51/Cr from radiolabeled endothelial cells. Monolayers were completely destroyed and replaced by hyphae after 18 hours of incubation. In contrast, when added 2 hours after the monolayers had been infected with Candida, neutrophils selectively migrated toward and attached to hyphae at points of hyphal penetration into individual endothelial cellsmore » (observed by time-lapse video-microscopy). Attached neutrophils spread over hyphal surfaces both within and beneath the endothelial cells; neutrophil recruitment to initial sites of leukocyte-Candida-endothelial cell interactions continued throughout the first 60 minutes of observation. Neutrophil spreading and stasis were observed only along Candida hyphae and at sites of Candida-endothelial cell interactions. These events resulted in 58.0% killing of Candida at 2 hours and subsequent clearance of Candida from endothelial cell monolayers, as determined by microcolony counts and morphological observation. On introduction of additional neutrophils to yield higher ratios of neutrophils to endothelial cells (10 neutrophils:1 endothelial cell), neutrophil migration toward hyphal elements continued. Despite retraction or displacement of occasional endothelial cells by invading Candida and neutrophils, most endothelial cells remained intact, viable, and motile as verified both by morphological observations and measurement of /sup 51/Cr release from radiolabeled monolayers.« less

Oral candidiasis in immunosuppressed children and young adults after liver or kidney transplantation.

PubMed

Olczak-Kowalczyk, Dorota; Pawłowska, Joanna; Garczewska, Barbara; Smirska, Ewa; Grenda, Ryszard; Syczewska, Małgorzata; Kowalczyk, Wojciech

2010-01-01

Candidiasis is an infectious complication in organ transplant recipients resulting from the patients' immunodeficiency and virulence of fungi pathogens. The purpose of this study was to evaluate the frequency of Candida spp. and identify their presence in the oral lesions of graft recipients. This study included 185 patients, 1.5 to 25.2 years of age (mean = 13.1 +/- 4.2 years) who were receiving combined immunosuppression treatment after kidney or liver transplantation and 70 control subjects. Evaluation included clinical oral examination, mycology, and statistical analysis. Candida spp. colonies were found in the oral mucosa of 63 (34%) graft recipients and in 19 (27%) control subjects. Candida albicans was the most prevalent species. This study showed that, regardless of the type of the organ transplant and immunosuppression, frequent, regular oral follow-up and mycologic tests are recommended. Diagnosing increased density of Candida spp. colonies in the oral cavity will help initiate early antifungal treatment. Candida spp. prevalence in the oral cavity in transplant recipients was higher than in immunocompetent control subjects. Kidney or liver transplantation predisposes one to the development of an increased density of Candida spp. colonies.

Diffusible signal factor-dependent quorum sensing in pathogenic bacteria and its exploitation for disease control.

PubMed

Dow, J M

2017-01-01

Cell-to-cell signals of the diffusible signal factor (DSF) family are cis-2-unsaturated fatty acids of differing chain length and branching pattern. DSF signalling has been described in diverse bacteria to include plant and human pathogens where it acts to regulate functions such as biofilm formation, antibiotic tolerance and the production of virulence factors. DSF family signals can also participate in interspecies signalling with other bacteria and interkingdom signalling such as with the yeast Candida albicans. Interference with DSF signalling may afford new opportunities for the control of bacterial disease. Such strategies will depend in part on detailed knowledge of the molecular mechanisms underlying the processes of signal synthesis, perception and turnover. Here, I review both recent progress in understanding DSF signalling at the molecular level and prospects for translating this knowledge into approaches for disease control. © 2016 The Society for Applied Microbiology.

Antimicrobial activity of cream incorporated with silver nanoparticles biosynthesized from Withania somnifera

PubMed Central

Marslin, Gregory; Selvakesavan, Rajendran K; Franklin, Gregory; Sarmento, Bruno; Dias, Alberto CP

2015-01-01

We report on the antimicrobial activity of a cream formulation of silver nanoparticles (AgNPs), biosynthesized using Withania somnifera extract. Aqueous extracts of leaves promoted efficient green synthesis of AgNPs compared to fruits and root extracts of W. somnifera. Biosynthesized AgNPs were characterized for their size and shape by physical-chemical techniques such as UV-visible spectroscopy, laser Doppler anemometry, transmission electron microscopy, scanning electron microscopy, atomic force microscopy, X-ray diffraction, and X-ray energy dispersive spectroscopy. After confirming the antimicrobial potential of AgNPs, they were incorporated into a cream. Cream formulations of AgNPs and AgNO3 were prepared and compared for their antimicrobial activity against human pathogens (Staphylococcus aureus, Pseudomonas aeruginosa, Proteus vulgaris, Escherichia coli, and Candida albicans) and a plant pathogen (Agrobacterium tumefaciens). Our results show that AgNP creams possess significantly higher antimicrobial activity against the tested organisms. PMID:26445537

Role of pathogen-associated molecular patterns (PAMPS) in immune responses to fungal infections.

PubMed

Taghavi, Mehdi; Khosravi, Alireza; Mortaz, Esmaeil; Nikaein, Donya; Athari, Seyyed Shamsadin

2017-08-05

Recent years have seen the rise of invasive fungal infections, which are mostly due to the increase in patients. Three major opportunistic fungal species in human are Aspergillus fumigatus, Candida albicans, and Cryptococcus neoformans that pose the biggest concern for these immunocompromised patients' mortality. The growing occurrence of opportunistic fungal infections has sparked the interest to understand defense mechanisms against pathogenic fungi. Toll-like receptors (TLRs), as a part of innate immune system, play an important role for recognizing the invading microorganisms and initiating sufficient immune responses. Recent studies have revealed an integrated role for TLR, signaling inactivating immune defense mechanisms against exact fungi. Among TLRs, TLR2 and TLR4 are the major participants in fungi recognition. The present paper highlights the role of TLR participants in fungal recognition as well as their mechanisms. Copyright © 2016 Elsevier B.V. All rights reserved.

First report of monomicrobial Candida parapsilosis necrotizing fasciitis.

PubMed

Gassiep, I; Douglas, J; Playford, E G

2016-10-01

Candida parapsilosis is an emerging pathogen worldwide. It commonly causes soft tissue infection; however, to our knowledge there has been no previous report of monomicrobial necrotizing soft tissue infection (NSTI) secondary to C. parapsilosis. We report the first case of NSTI caused by C. parapsilosis in an immunocompromised renal transplant patient, with the diagnosis proven both histologically and microbiologically. Our patient required aggressive surgical intervention and antifungal therapy, with postoperative survival at 90 days. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Cyclic dipeptides from rhabditid entomopathogenic nematode-associated Bacillus cereus have antimicrobial activities.

PubMed

Nishanth Kumar, S; Nath, Vishnu Sukumari; Pratap Chandran, R; Nambisan, Bala

2014-02-01

The cell free culture filtrate of Bacillus cereus associated with an entomopathogenic nematode, Rhabditis (Oscheius) sp. exhibited strong antimicrobial activity. The ethyl acetate extract of the bacterial culture filtrate was purified by silica gel column chromatography to obtain four bioactive compounds. The structure and absolute stereochemistry of these compounds were determined based on extensive spectroscopic analyses (FABMS, (1)H NMR, (13)C NMR, (1)H-(1)H COSY, (1)H-(13)C HMBC) and Marfey's method. The compounds were identified as cyclic dipeptides (CDPs): cyclo(L-Pro-L-Trp), cyclo(L-Leu-L-Val), cyclo(D-Pro-D-Met), and cyclo(D-Pro-D-Phe), respectively. Compounds recorded significant antibacterial activity against all the test bacteria (Staphylococcus epidermidis, Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa and methicillin-resistant S. aureus) except cyclo(L-Leu-L-Val). Cyclo(L-Leu-L-Val) recorded activity only against Gram positive bacteria. Best antibacterial activity was recorded by cyclo(L-Pro-L-Trp) against S. aureus (4 μg/ml). The four compounds were active against all the five fungi tested (Trichophyton rubrum, Aspergillus flavus, Candida albicans, Candida tropicalis and Cryptococcus neoformans) and the activity was compared with amphotericin B, the standard fungicide. The highest activity of 1 μg/ml by cyclo(L-Pro-L-Trp) was recorded against T. rubrum, a human pathogen responsible for causing athlete's foot, jock itch, and ringworm. The activity of cyclo(L-Pro-L-Trp) against T. rubrum, C. neoformans and C. albicans were better than amphotericin B, the standard antifungal agent. To our knowledge, this is the first report of antifungal activity of CDPs against the human pathogenic fungi T. rubrum and C. neoformans. The four CDPs are nontoxic to healthy human cell line up to 200 μg/ml. We conclude that the bacterium associated with entomopathogenic nematode is promising sources of natural antimicrobial secondary metabolites, which may receive greater benefit as potential sources of new drugs in the pharmaceutical industry.

Oral Candidal Carriage in Subjects with Pure Vegetarian and Mixed Dietary Habits

PubMed Central

Patil, Shankargouda; Rao, Roopa S; Sanketh, D.S.; Sarode, Sachin; Sarode, Gargi

2017-01-01

Introduction Candida albicans being a part of the normal oral microbial flora is one of the most commonly isolated species from the oral cavity. Recent studies have shown a steady rise in the number of non C. albicans species, which are relatively resistant to common antifungal agents and are being recognized as potential pathogens. It is vital to ascertain the predisposing factors leading to such a shift in the oral candidal flora. Aim To estimate the prevalence of candidal species among vegetarians and non-vegetarians. Materials and Methods Clinical data including age, gender, and diet preference of 238 participants were noted. Participants with a history of systemic disorders, oral prosthesis, salivary gland disorders and habits such as smoking, alcoholism, and tobacco usage were excluded from the study. The participants were asked to gargle a 10 ml solution of phosphate buffered saline for one minute before depositing the same in a sterile container. The samples were cultured using Hicrome agar media. Data analysis was carried out using Statistical Package for Social Sciences (SPSS software) version 10.5 and differences between individual groups were tested by Chi-square test. Results Among 238 samples, 127 (53.3%) samples were positive for Candida. The candidal prevalence in vegetarians (68.5%) was higher than non-vegetarians (40.7%). C. albicans was the most common species to be isolated in both vegetarians (35.1%) and non-vegetarians (39.2%). Candida glabrata and Candida tropicalis showed a higher prevalence in vegetarians (30.5% and 10.1%, respectively) in comparison to non-vegetarians (8.4% and 2.3%, respectively). Candida krusei was isolated only from vegetarians (4.6%). Conclusion Results indicate that diet plays a major role in oral candidal prevalence and species specificity which in turn may predispose the vegetarians toward these pathogenic organisms. PMID:28893036

Antifungal Activity of Lactic Acid Bacteria Strains Isolated from Natural Honey against Pathogenic Candida Species

PubMed Central

Bulgasem, Bulgasem Y.; Lani, Mohd Nizam; Wan Yusoff, Wan Mohtar; Fnaish, Sumaya G.

2016-01-01

The role of lactic acid bacteria (LAB) in honey as antifungal activity has received little attention and their mechanism of inhibitory of fungi is not fully understood. In this study, LAB were isolated from honey samples from Malaysia, Libya, Saudi Arabia, and Yemen. Twenty-five isolates were confirmed LAB by catalase test and Gram staining, and were screened for antifungal activity. Four LAB showed inhibitory activity against Candida spp. using the dual agar overlay method. And they were identified as Lactobacillus plantarum HS isolated from Al-Seder honey, Lactobacillus curvatus HH isolated from Al-Hanon honey, Pediococcus acidilactici HC isolated from Tualang honey and Pediococcus pentosaceus HM isolated from Al-Maray honey by the 16S rDNA sequence. The growth of Candida glabrata ATCC 2001 was strongly inhibited (>15.0 mm) and (10~15 mm) by the isolates of L. curvatus HH and P. pentosaceus HM, respectively. The antifungal activity of the crude supernatant (cell free supernatant, CFS) was evaluated using well diffusion method. The CFS showed high antifungal activity against Candida spp. especially The CFS of L. curvatus HH was significantly (p < 0.05) inhibited growth of C. glabrata ATCC 2001, C. parapsilosis ATCC 2201, and C. tropicalis ATCC 750 with inhibitory zone 22.0, 15.6, and 14.7 mm, respectively. While CFS of P. pentosaceus HM was significantly (p < 0.05) effective against C. krusei, C. glabrata, and C. albicans with inhibition zone 17.2, 16.0, and 13.3 mm, respectively. The results indicated that LAB isolated from honey produced compounds which can be used to inhibit the growth of the pathogenic Candida species. PMID:28154488

Oral Candidal Carriage in Subjects with Pure Vegetarian and Mixed Dietary Habits.

PubMed

Patil, Shankargouda; Rao, Roopa S; Raj, A Thirumal; Sanketh, D S; Sarode, Sachin; Sarode, Gargi

2017-07-01

Candida albicans being a part of the normal oral microbial flora is one of the most commonly isolated species from the oral cavity. Recent studies have shown a steady rise in the number of non C. albicans species, which are relatively resistant to common antifungal agents and are being recognized as potential pathogens. It is vital to ascertain the predisposing factors leading to such a shift in the oral candidal flora. To estimate the prevalence of candidal species among vegetarians and non-vegetarians. Clinical data including age, gender, and diet preference of 238 participants were noted. Participants with a history of systemic disorders, oral prosthesis, salivary gland disorders and habits such as smoking, alcoholism, and tobacco usage were excluded from the study. The participants were asked to gargle a 10 ml solution of phosphate buffered saline for one minute before depositing the same in a sterile container. The samples were cultured using Hicrome agar media. Data analysis was carried out using Statistical Package for Social Sciences (SPSS software) version 10.5 and differences between individual groups were tested by Chi-square test. Among 238 samples, 127 (53.3%) samples were positive for Candida . The candidal prevalence in vegetarians (68.5%) was higher than non-vegetarians (40.7%). C. albicans was the most common species to be isolated in both vegetarians (35.1%) and non-vegetarians (39.2%). Candida glabrata and Candida tropicalis showed a higher prevalence in vegetarians (30.5% and 10.1%, respectively) in comparison to non-vegetarians (8.4% and 2.3%, respectively). Candida krusei was isolated only from vegetarians (4.6%). Results indicate that diet plays a major role in oral candidal prevalence and species specificity which in turn may predispose the vegetarians toward these pathogenic organisms.

Distribution of Candida albican genotype and Candida species is associated with the severity of vulvovagianl candidiasis.

PubMed

Zeng, Jun; Zong, Li-li; Mao, Ting; Huang, Yu-xing; Xu, Zheng-mei

2011-10-01

To investigate the distribution of pathogenic C.albican genotype and Candida species in association with the severity of vulvovaginal candidiasis (VVC). Polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) of the internal transcribed spacer analysis was employed to identify the Candida species isolated from the vaginal secretions of 198 patients with acute VVC. SSCP and GeneScan analyses of microsatellite locus I polymorphism were used to determine the genotypes of the clinical isolates of C. albican associated with VVC. All the patients were scored for clinical signs and symptoms to evaluate the severity of VVC. A total of 198 Candida strains were isolated from VVC patients, including 140 (70.7%) C. albicans strains and 58 (29.3%) non-albicans strains. In the 95 patients with severe VVC and 103 with mild-moderate VVC, C.albican was detected in 62.1% and 76.6% of the patients, respectively (P=0.011). Thirty-eight microsatellite locus I genotypes were detected in 140 unrelated C. albican strains, among which the dominant genotypes 30-45 (44 strians, 31.43%) and 32-46 (23 strains, 16.43%) were the most common, followed by genotypes 30-46 (4 strains, 2.86%) and 32-47 (9 strains, 6.42%). The overall frequencies of the 4 genotypes were significantly higher in severe VVC than in mild-moderate VVC cases (77.9% vs 42.0%, P<0.001). C. albicans remains the most common pathogenic Candia species in patients with VVC, but the non-alibcans species seem more likely to cause severe VVC. The dominant genotypes of C. albicans with a tropism for the vagina are correlated to the severity of VVC.

Antifungal Activity of Lactic Acid Bacteria Strains Isolated from Natural Honey against Pathogenic Candida Species.

PubMed

Bulgasem, Bulgasem Y; Lani, Mohd Nizam; Hassan, Zaiton; Wan Yusoff, Wan Mohtar; Fnaish, Sumaya G

2016-12-01

The role of lactic acid bacteria (LAB) in honey as antifungal activity has received little attention and their mechanism of inhibitory of fungi is not fully understood. In this study, LAB were isolated from honey samples from Malaysia, Libya, Saudi Arabia, and Yemen. Twenty-five isolates were confirmed LAB by catalase test and Gram staining, and were screened for antifungal activity. Four LAB showed inhibitory activity against Candida spp. using the dual agar overlay method. And they were identified as Lactobacillus plantarum HS isolated from Al-Seder honey, Lactobacillus curvatus HH isolated from Al-Hanon honey, Pediococcus acidilactici HC isolated from Tualang honey and Pediococcus pentosaceus HM isolated from Al-Maray honey by the 16S rDNA sequence. The growth of Candida glabrata ATCC 2001 was strongly inhibited (>15.0 mm) and (10~15 mm) by the isolates of L. curvatus HH and P. pentosaceus HM, respectively. The antifungal activity of the crude supernatant (cell free supernatant, CFS) was evaluated using well diffusion method. The CFS showed high antifungal activity against Candida spp. especially The CFS of L. curvatus HH was significantly ( p < 0.05) inhibited growth of C. glabrata ATCC 2001, C. parapsilosis ATCC 2201, and C. tropicalis ATCC 750 with inhibitory zone 22.0, 15.6, and 14.7 mm, respectively. While CFS of P. pentosaceus HM was significantly ( p < 0.05) effective against C. krusei , C. glabrata , and C. albicans with inhibition zone 17.2, 16.0, and 13.3 mm, respectively. The results indicated that LAB isolated from honey produced compounds which can be used to inhibit the growth of the pathogenic Candida species.

Antimicrobial activity of yeasts against some pathogenic bacteria

PubMed Central

Younis, Gamal; Awad, Amal; Dawod, Rehab E.; Yousef, Nehal E.

2017-01-01

Aim: This study was designed to isolate and identify yeast species from milk and meat products, and to test their antimicrobial activity against some bacterial species. Materials and Methods: A total of 160 milk and meat products samples were collected from random sellers and super markets in New Damietta city, Damietta, Egypt. Samples were subjected to yeast isolation procedures and tested for its antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. In addition, all yeast species isolates were subjected to polymerase chain reaction (PCR) for detection of khs (kievitone hydratase) and pelA (pectate degrading enzyme)genes. Results: The recovery rate of yeasts from sausage was 20% (2/10) followed by kareish cheese, processed cheese, and butter 10% (1/10) each as well as raw milk 9% (9/100), and fruit yoghurt 30% (6/20). Different yeast species were recovered, namely, Candida kefyr (5 isolates), Saccharomyces cerevisiae (4 isolates), Candida intermedia (3 isolates), Candida tropicalis (2 isolates), Candida lusitaniae (2 isolates), and Candida krusei (1 isolate). khs gene was detected in all S. cerevisiae isolates, however, pelA gene was not detected in all identified yeast species. Antimicrobial activity of recovered yeasts against the selected bacterial species showed high activity with C. intermedia against S. aureus and E. coli, C. kefyr against E. coli, and C. lusitaniae against S. aureus. Moderate activities were obtained with C. tropicalis, C. lusitaniae, and S. cerevisiae against E. coli; meanwhile, all the tested yeasts revealed a very low antimicrobial activity against P. aeruginosa. Conclusion: The obtained results confirmed that some kinds of yeasts have the ability to produce antimicrobial compounds that could inhibit some pathogenic and spoilage bacteria and these antimicrobial activity of yeasts enables them to be one of the novel agents in controlling spoilage of food. PMID:28919693

AFM combined to ATR-FTIR reveals Candida cell wall changes under caspofungin treatment.

PubMed

Quilès, Fabienne; Accoceberry, Isabelle; Couzigou, Célia; Francius, Grégory; Noël, Thierry; El-Kirat-Chatel, Sofiane

2017-09-21

Fungal pathogens from Candida genus are responsible for severe life-threatening infections and the antifungal arsenal is still limited. Caspofungin, an antifungal drug used for human therapy, acts as a blocking agent of the cell wall synthesis by inhibiting the β-1,3-glucan-synthase encoded by FKS genes. Despite its efficiency, the number of genetic mutants that are resistant to caspofungin is increasing. An important challenge to improve antifungal therapy is to understand cellular phenomenon that are associated with drug resistance. Here we used atomic force microscopy (AFM) combined to Fourier transform infrared spectroscopy in attenuated total reflection mode (ATR-FTIR) to decipher the effect of low and high drug concentration on the morphology, mechanics and cell wall composition of two Candida strains, one susceptible and one resistant to caspofungin. Our results confirm that caspofungin induces a dramatic cell wall remodelling via activation of stress responses, even at high drug concentration. Additionally, we highlighted unexpected changes related to drug resistance, suggesting that caspofungin resistance associated with FKS gene mutations comes from a combination of effects: (i) an overall remodelling of yeast cell wall composition; and (ii) cell wall stiffening through chitin synthesis. This work demonstrates that AFM combined to ATR-FTIR is a valuable approach to understand at the molecular scale the biological mechanisms associated with drug resistance.

Biofilm production and antifungal susceptibility of co-cultured Malassezia pachydermatis and Candida parapsilosis isolated from canine seborrheic dermatitis.

PubMed

Bumroongthai, K; Chetanachan, P; Niyomtham, W; Yurayart, C; Prapasarakul, N

2016-07-01

The yeasts Malassezia (M.) pachydermatis and Candida (C.) parapsilosis are often co-isolated in case of canine seborrhea dermatitis (SD) and also are emerging as opportunistic pathogens of immunocompromised human beings. Increased information about how their relationship results in biofilm production and an antifungal response would be useful to inform treatment and control. This study was designed to investigate biofilm production derived from co-culture of M. pachydermatis and C. parapsilosis from dog skin and to determine their in vitro antifungal susceptibility. We demonstrated that regardless of yeast strain or origin all single and dual cultures produced biofilms within 24 hours, and the greatest amount was present after 72 hours. Biofilm production from mixed cultures was greater than for single strains (P < .05). All sessile forms of the single and dual cultures were resistant to the tested antifungals itraconazole and ketoconazole, whereas planktonic forms were susceptible. The study suggests that dual cultures produce stronger biofilms that are likely to enhance persistence in skin lesions in dogs and result in greater resistance to antifungal treatment. © The Author 2016. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

In vitro inhibitory activity of probiotic products against oral Candida species.

PubMed

Zhao, C; Lv, X; Fu, J; He, C; Hua, H; Yan, Z

2016-07-01

To evaluate the inhibitory activity of probiotics against oral Candida species. Four commercial probiotic products were screened. Bacillus subtilis R0179 was found to have a significant antifungal effect. Bacillus subtilis-Candida interactions were evaluated using disc diffusion tests, confocal laser scanning microscopy, scanning electron microscopy and interaction with engineered human oral mucosa tissue. Bacillus subtilis exhibited clear zones of inhibition for Candida albicans and Candida parapsilosis but not for Candida krusei. A remarkable reduction in the number of Candida cells and abundant Candida cell death were visualized with confocal laser scanning microscopy. Shrinkage and deformation of Candida cells was observed using scanning electron microscopy. Culture of C. albicans on engineered human oral mucosa tissues resulted in the presence of a large number of yeast cells on the tissue surface and the development of large-scale tissue damage. However, comparatively fewer Candida cells were observed on B. subtilis-treated tissues. We also use ultra performance liquid chromatography/time of flight mass spectrometry (UPLC/TOF MS) to explore the preliminary antifungal mechanism of B. subtilis R0179 and to detect that whether it can secrete an antifungal agent, Iturin A. Bacillus subtilis R0179 exhibits a significant inhibitory effect on the growth of Candida species. Bacillus subtilis has the potential to be used in the prevention or treatment of oral candidiasis. © 2016 The Society for Applied Microbiology.

Anethole induces apoptotic cell death accompanied by reactive oxygen species production and DNA fragmentation in Aspergillus fumigatus and Saccharomyces cerevisiae.

PubMed

Fujita, Ken-Ichi; Tatsumi, Miki; Ogita, Akira; Kubo, Isao; Tanaka, Toshio

2014-02-01

trans-Anethole (anethole), a major component of anise oil, has a broad antimicrobial spectrum, and antimicrobial activity that is weaker than that of other antibiotics on the market. When combined with polygodial, nagilactone E, and n-dodecanol, anethole has been shown to possess significant synergistic antifungal activity against a budding yeast, Saccharomyces cerevisiae, and a human opportunistic pathogenic yeast, Candida albicans. However, the antifungal mechanism of anethole has not been completely determined. We found that anethole stimulated cell death of a human opportunistic pathogenic fungus, Aspergillus fumigatus, in addition to S. cerevisiae. The anethole-induced cell death was accompanied by reactive oxygen species production, metacaspase activation, and DNA fragmentation. Several mutants of S. cerevisiae, in which genes related to the apoptosis-initiating execution signals from mitochondria were deleted, were resistant to anethole. These results suggest that anethole-induced cell death could be explained by oxidative stress-dependent apoptosis via typical mitochondrial death cascades in fungi, including A. fumigatus and S. cerevisiae. © 2014 FEBS.

Biological activity of Tat (47-58) peptide on human pathogenic fungi

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jung, Hyun Jun; Park, Yoonkyung; Department of Biotechnology, Chosun University, 375 Seosuk-dong, Kwangju 501-750

2006-06-23

Tat (47-58) peptide, a positively charged Arginine-rich peptide derived from HIV-1 regulatory protein Tat, is known for a peptidic delivery factor as a cell-penetrating peptide on mammalian cells. In this study, antifungal effect and its mode of action of Tat peptide were investigated on fungal cells. The results indicate that Tat peptide exhibits antifungal activity against pathogenic fungal cells without hemolytic effect on human erythrocytes. To understand the mechanism(s) of Tat peptide, the cellular distribution of the peptide was investigated. Tat peptide internalized in the fungal cells without any damage to cell membrane when examined using an artificial liposome (PC/cholesterol;more » 10:1, w/w). Moreover, flow cytometry analysis exhibited the uptake of Tat peptide by energy- and salt-independent pathway, and confocal scanning microscopy displayed that this peptide accumulated in the nucleus of fungal cells rapidly without any impediment by time or temperature, which generally influence on the viral infections. After penetration into the nuclear, the peptide affected the process of cell cycle of Candida albicans through the arrest at G1 phase.« less

Biological activity of Tat (47-58) peptide on human pathogenic fungi.

PubMed

Jung, Hyun Jun; Park, Yoonkyung; Hahm, Kyung-Soo; Lee, Dong Gun

2006-06-23

Tat (47-58) peptide, a positively charged Arginine-rich peptide derived from HIV-1 regulatory protein Tat, is known for a peptidic delivery factor as a cell-penetrating peptide on mammalian cells. In this study, antifungal effect and its mode of action of Tat peptide were investigated on fungal cells. The results indicate that Tat peptide exhibits antifungal activity against pathogenic fungal cells without hemolytic effect on human erythrocytes. To understand the mechanism(s) of Tat peptide, the cellular distribution of the peptide was investigated. Tat peptide internalized in the fungal cells without any damage to cell membrane when examined using an artificial liposome (PC/cholesterol; 10:1, w/w). Moreover, flow cytometry analysis exhibited the uptake of Tat peptide by energy- and salt-independent pathway, and confocal scanning microscopy displayed that this peptide accumulated in the nucleus of fungal cells rapidly without any impediment by time or temperature, which generally influence on the viral infections. After penetration into the nuclear, the peptide affected the process of cell cycle of Candida albicans through the arrest at G1 phase.

Candida krusei isolated from fruit juices ultrafiltration membranes promotes colonization of Escherichia coli O157:H7 and Salmonella enterica on stainless steel surfaces.

PubMed

Tarifa, María Clara; Lozano, Jorge Enrique; Brugnoni, Lorena Inés

2017-02-01

To clarify the interactions between a common food spoilage yeast and two pathogenic bacteria involved in outbreaks associated with fruit juices, the present paper studies the effect of the interplay of Candida krusei, collected from UF membranes, with Escherichia coli O157:H7 and Salmonella enterica in the overall process of adhesion and colonization of abiotic surfaces. Two different cases were tested: a) co-adhesion by pathogenic bacteria and yeasts, and b) incorporation of bacteria to pre-adhered C. krusei cells. Cultures were made on stainless steel at 25°C using apple juice as culture medium. After 24 h of co-adhesion with C. krusei, both E. coli O157:H7 and S. enterica increased their counts 1.05 and 1.11 log CFU cm 2 , respectively. Similar increases were obtained when incorporating bacteria to pre-adhered cells of Candida. Nevertheless C. krusei counts decreased in both experimental conditions, in a) 0.40 log CFU cm 2 and 0.55 log CFU cm 2 when exposed to E. coli O157:H7 and S. enterica and in b) 0.18 and 0.68 log CFU cm 2 , respectively. This suggests that C. krusei, E. coli O157:H7, and S. enterica have a complex relationship involving physical and chemical interactions on food contact surfaces. This study supports the possibility that pathogen interactions with members of spoilage microbiota, such as C. krusei, might play an important role for the survival and dissemination of E. coli O157:H7 and Salmonella enterica in food-processing environments. Based on the data obtained from the present study, much more attention should be given to prevent the contamination of these pathogens in acidic drinks.

[Differentiation and characterization of yeasts pathogenic for humans (Candida albicans, Exophiala dermatitidis) and algae pathogenic for animals (Prototheca spp.) using Fourier transform infrared spectroscopy (FTIR) in comparison with conventional methods].

PubMed

Schmalreck, A F; Tränkle, P; Vanca, E; Blaschke-Hellmessen, R

1998-01-01

Due to the Fourier-Transform Infrared Spectroscopy (FT-IR) of strain specific traits demonstrated to be a suitable and efficient method for diagnostic and epidemiological determinations for the yeasts Candida albicans, Exophiala dermatitidis and the chlorophylless algae of the genus Prototheca. FT-IR leads in a rapid and economical way to reproducible results according to the spectral differences of intact cells (IR-fingerprints). Different genera, species and sub-species respectively, different strains can be recognized and grouped into different clusters and subclusters. The FT-IR analysis of Candida albicans isolates (n = 150) of 22 newborns-at-risk of an intensive care unit showed, that 86% of the children were colonised with several (2-4) different strains in the oral cavities and faeces. Stationary cross-infections could definitely be determined. Exophiala dermatitidis isolates (n = 31), mostly isolated repetitively within a period of 3 years from sputa of patients suffering from cystic fibrosis could be characterized and grouped patient-specifically over the total sampling period. Of 6 from 8 patients (75%) their individual strains remain the same and could be tracked over the three years. Cross-infections during the stationary treatment could be clearly identified by FT-IR. The Prototheca isolate (n = 43) from live-stock and farm environment showed clear distinguishable clusters differentiating the species P. wickerhamii, P. zopfii and P. stagnora. In addition, the biotypes of P. zopfii could be distinguished, especially the subclusters of variants II and III. It could be demonstrated, that FT-IR is suitable for the routine identification and differentiation of yeasts and algae. However, in spite of the gain of knowledge by using FT-IR for the characterization of microorganisms, the conventional phenotyping and/or genetic analysis of yeast or algae strains cannot be replaced completely. For a final taxonomic classification a combination of conventional methods on FT-IR together with more sophisticated molecular genetic procedures is necessary.

Factor H Binds to Extracellular DNA Traps Released from Human Blood Monocytes in Response to Candida albicans

PubMed Central

Halder, Luke D.; Abdelfatah, Mahmoud A.; Jo, Emeraldo A. H.; Jacobsen, Ilse D.; Westermann, Martin; Beyersdorf, Niklas; Lorkowski, Stefan; Zipfel, Peter F.; Skerka, Christine

2017-01-01

Upon systemic infection with human pathogenic yeast Candida albicans (C. albicans), human monocytes and polymorph nuclear neutrophilic granulocytes are the first immune cells to respond and come into contact with C. albicans. Monocytes exert immediate candidacidal activity and inhibit germination, mediate phagocytosis, and kill fungal cells. Here, we show that human monocytes spontaneously respond to C. albicans cells via phagocytosis, decondensation of nuclear DNA, and release of this decondensed DNA in the form of extracellular traps (called monocytic extracellular traps: MoETs). Both subtypes of monocytes (CD14++CD16−/CD14+CD16+) formed MoETs within the first hours upon contact with C. albicans. MoETs were characterized by the presence of citrullinated histone, myeloperoxidase, lactoferrin, and elastase. MoETs were also formed in response to Staphylococcus aureus and Escherichia coli, indicating a general reaction of monocytes to infectious microbes. MoET induction differs from extracellular trap formation in macrophages as MoETs are not triggered by simvastatin, an inhibitor of cholesterol synthesis and inducer of extracellular traps in macrophages. Extracellular traps from both monocytes and neutrophils activate complement and C3b is deposited. However, factor H (FH) binds via C3b to the extracellular DNA, mediates cofactor activity, and inhibits the induction of the inflammatory cytokine interleukin-1 beta in monocytes. Altogether, the results show that human monocytes release extracellular DNA traps in response to C. albicans and that these traps finally bind FH via C3b to presumably support clearance without further inflammation. PMID:28133459

Antimicrobial Activities of Bacteria Associated with the Brown Alga Padina pavonica

PubMed Central

Ismail, Amel; Ktari, Leila; Ahmed, Mehboob; Bolhuis, Henk; Boudabbous, Abdellatif; Stal, Lucas J.; Cretoiu, Mariana Silvia; El Bour, Monia

2016-01-01

Macroalgae belonging to the genus Padina are known to produce antibacterial compounds that may inhibit growth of human- and animal pathogens. Hitherto, it was unclear whether this antibacterial activity is produced by the macroalga itself or by secondary metabolite producing epiphytic bacteria. Here we report antibacterial activities of epiphytic bacteria isolated from Padina pavonica (Peacocks tail) located on northern coast of Tunisia. Eighteen isolates were obtained in pure culture and tested for antimicrobial activities. Based on the 16S rRNA gene sequences the isolates were closely related to Proteobacteria (12 isolates; 2 Alpha- and 10 Gammaproteobacteria), Firmicutes (4 isolates) and Actinobacteria (2 isolates). The antimicrobial activity was assessed as inhibition of growth of 12 species of pathogenic bacteria (Aeromonas salmonicida, A. hydrophila, Enterobacter xiangfangensis, Enterococcus faecium, Escherichia coli, Micrococcus sp., Salmonella typhimurium, Staphylococcus aureus, Streptococcus sp., Vibrio alginoliticus, V. proteolyticus, V. vulnificus) and one pathogenic yeast (Candida albicans). Among the Firmicutes, isolate P8, which is closely related to Bacillus pumilus, displayed the largest spectrum of growth inhibition of the pathogenic bacteria tested. The results emphasize the potential use of P. pavonica associated antagonistic bacteria as producers of novel antibacterial compounds. PMID:27462308

Identification of Candida Species Isolated from Renal Transplant Recipients with Candiduria

PubMed Central

Yazdani, M. R.; Foroughifar, E.; Mohammadi, R.

2016-01-01

Background: Renal transplantation has long been considered the gold standard medical care for patients with end-stage renal disease. Candiduria continue to be a significant complication for renal transplant recipients. The risk of infections depends on the amount of immunosuppression and exposure to the potential pathogens. Objective: Molecular identification of Candida species isolated from renal transplant recipients with candiduria. Methods: Between 2009 and 2014, 62 Candida isolates were collected from 485 renal transplant recipients. All isolates were identified by PCR-RFLP profiles after digestion with the restriction enzyme MspI. Results: C. albicans (44%) and C. parapsilosis complex (5%) had the most and the least prevalence, respectively. Male to female ratio was 26/36, ranging in age from 19 to 62 years. Conclusion: Due to the fact that candiduria is connected with increased mortality in renal transplant recipients, precise identification of Candida species by molecular techniques can lead to an appropriate therapy among high risk patients. C. albicans remains the most prevalent species isolated from renal transplant recipients, Nevertheless, the number of non-C. albicans Candida species looks to be emerging. PMID:28078059

Synergistic combinations of antifungals and anti-virulence agents to fight against Candida albicans

PubMed Central

Cui, Jinhui; Ren, Biao; Tong, Yaojun; Dai, Huanqin; Zhang, Lixin

2015-01-01

Candida albicans, one of the pathogenic Candida species, causes high mortality rate in immunocompromised and high-risk surgical patients. In the last decade, only one new class of antifungal drug echinocandin was applied. The increased therapy failures, such as the one caused by multi-drug resistance, demand innovative strategies for new effective antifungal drugs. Synergistic combinations of antifungals and anti-virulence agents highlight the pragmatic strategy to reduce the development of drug resistant and potentially repurpose known antifungals, which bypass the costly and time-consuming pipeline of new drug development. Anti-virulence and synergistic combination provide new options for antifungal drug discovery by counteracting the difficulty or failure of traditional therapy for fungal infections. PMID:26048362

A rapid, highly sensitive and culture-free detection of pathogens from blood by positive enrichment.

PubMed

Vutukuru, Manjula Ramya; Sharma, Divya Khandige; Ragavendar, M S; Schmolke, Susanne; Huang, Yiwei; Gumbrecht, Walter; Mitra, Nivedita

2016-12-01

Molecular diagnostics is a promising alternative to culture based methods for the detection of bloodstream infections, notably due to its overall lower turnaround time when starting directly from patient samples. Whole blood is usually the starting diagnostic sample in suspected bloodstream infections. The detection of low concentrations of pathogens in blood using a molecular assay necessitates a fairly high starting volume of blood sample in the range of 5-10mL. This large volume of blood sample has a substantial accompanying human genomic content that interferes with pathogen detection. In this study, we have established a workflow using magnetic beads coated with Apolipoprotein H that makes it possible to concentrate pathogens from a 5.0mL whole blood sample, thereby enriching pathogens from whole blood background and also reducing the sample volume to ~200μL or less. We have also demonstrated that this method of enrichment allows detection of 1CFU/mL of Escherichia coli, Enterococcus gallinarum and Candida tropicalis from 5mL blood using quantitative PCR; a detection limit that is not possible in unenriched samples. The enrichment method demonstrated here took 30min to complete and can be easily integrated with various downstream molecular and microbiological techniques. Copyright © 2016 Elsevier B.V. All rights reserved.

Iron and copper as virulence modulators in human fungal pathogens.

PubMed

Ding, Chen; Festa, Richard A; Sun, Tian-Shu; Wang, Zhan-You

2014-07-01

Fungal pathogens have evolved sophisticated machinery to precisely balance the fine line between acquiring essential metals and defending against metal toxicity. Iron and copper are essential metals for many processes in both fungal pathogens and their mammalian hosts, but reduce viability when present in excess. However, during infection, the host uses these two metals differently. Fe has a long-standing history of influencing virulence in pathogenic fungi, mostly in regards to Fe acquisition. Numerous studies demonstrate the requirement of the Fe acquisition pathway of Candida, Cryptococcus and Aspergillus for successful systemic infection. Fe is not free in the host, but is associated with Fe-binding proteins, leading fungi to develop mechanisms to interact with and to acquire Fe from these Fe-bound proteins. Cu is also essential for cell growth and development. Essential Cu-binding proteins include Fe transporters, superoxide dismutase (SOD) and cytochrome c oxidase. Although Cu acquisition plays critical roles in fungal survival in the host, recent work has revealed that Cu detoxification is extremely important. Here, we review fungal responses to altered metal conditions presented by the host, contrast the roles of Fe and Cu during infection, and outline the critical roles of fungal metal homeostasis machinery at the host-pathogen axis. © 2014 John Wiley & Sons Ltd.

Screening of microbial contamination and antimicrobial activity of sea cucumber Holothuria polii.

PubMed

Omran, Nahla E E; Allam, Nanis G

2013-11-01

Microbiological studies were carried out on microbial contamination and antimicrobial activity of sea cucumber Holothuria polii collected from Mediterranean Sea at Abu-kir shore of Alexandria, Egypt. The obtained results revealed the presence of isolates of five human Gram-negative pathogenic bacteria, representing five genera were identified to species level, including, Esherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella sp. and Shigella sp. In addition, an yeast Candida albicans was isolated. The pathogenic bacteria were identified using API 20E strip system (BioMereux). All collected H. polii specimens were healthy with no external signs of infection. Histopathological study of the tegument, intestine and gonads showed no abnormal changes. The antimicrobial activity of two tegumental ethanol extracts (A and B, differ in the method of dehydration) were tested against wide range of pathogenic bacteria and fungi, including intestinal, skin and nosocomial pathogens and one plant fungal pathogen. The results revealed a remarkable antifungal activity of the extract B at 2.5 mg/ml MIC90, especially on Aspergillus niger, Scloretium sp, C. albicans, Aspergillus flavus and Malassezia furfur, and limited antibacterial activity against Gram-negative bacteria (Salmonella choleraesuis ATCC 14028 and Aeromonas hydrophila). The domain of bacterial and limited fungal contamination confirms the results that showed strong antifungal activity of investigated extract.

Fungal spondylodiscitis in a patient recovered from H7N9 virus infection: a case study and a literature review of the differences between Candida and Aspergillus spondylodiscitis * #

PubMed Central

Yu, Lie-dao; Feng, Zhi-yun; Wang, Xuan-wei; Ling, Zhi-heng; Lin, Xiang-jin

2016-01-01

To report a rare case of fungal spondylodiscitis in a patient recovered from H7N9 virus infection and perform a literature review of the different characteristics of Candida and Aspergillus spondylodiscitis, we reviewed cases of spondylodiscitis caused by Candida and Aspergillus species. Data, including patients’ information, pathogenic species, treatment strategy, outcomes, and relapses, were collected and summarized. The characteristics of Candida and Aspergillus spondylodiscitis were compared to see if any differences in clinical features, management, or consequences could be detected. The subject of the case study was first misdiagnosed as having a vertebral tumor, and then, following open biopsy, was diagnosed as having fungal spondylodiscitis. The patient made a good recovery following radical debridement. Seventy-seven additional cases of Candida spondylodiscitis and 94 cases of Aspergillus spondylodiscitis were identified in the literature. Patients with Candida spondylodiscitis tended to have a better outcome than patients with Aspergillus spondylodiscitis (cure rate 92.3% vs. 70.2%). Candida was found more frequently (47.8%) than Aspergillus (26.7%) in blood cultures, while neurological deficits were observed more often in patients with Aspergillus spondylodiscitis (43.6% vs. 25.6%). Candida spinal infections were more often treated by radical debridement (60.5% vs. 39.6%). Patients with Candida spondylodiscitis have better outcomes, which may be associated with prompt recognition, radical surgical debridement, and azoles therapy. A good outcome can be expected in fungal spondylodiscitis with appropriate operations and anti-fungal drugs. PMID:27819134

Differentiation of Candida albicans, Candida glabrata, and Candida krusei by FT-IR and chemometrics by CHROMagar™ Candida.

PubMed

Wohlmeister, Denise; Vianna, Débora Renz Barreto; Helfer, Virginia Etges; Calil, Luciane Noal; Buffon, Andréia; Fuentefria, Alexandre Meneghello; Corbellini, Valeriano Antonio; Pilger, Diogo André

2017-10-01

Pathogenic Candida species are detected in clinical infections. CHROMagar™ is a phenotypical method used to identify Candida species, although it has limitations, which indicates the need for more sensitive and specific techniques. Infrared Spectroscopy (FT-IR) is an analytical vibrational technique used to identify patterns of metabolic fingerprint of biological matrixes, particularly whole microbial cell systems as Candida sp. in association of classificatory chemometrics algorithms. On the other hand, Soft Independent Modeling by Class Analogy (SIMCA) is one of the typical algorithms still little employed in microbiological classification. This study demonstrates the applicability of the FT-IR-technique by specular reflectance associated with SIMCA to discriminate Candida species isolated from vaginal discharges and grown on CHROMagar™. The differences in spectra of C. albicans, C. glabrata and C. krusei were suitable for use in the discrimination of these species, which was observed by PCA. Then, a SIMCA model was constructed with standard samples of three species and using the spectral region of 1792-1561cm -1 . All samples (n=48) were properly classified based on the chromogenic method using CHROMagar™ Candida. In total, 93.4% (n=45) of the samples were correctly and unambiguously classified (Class I). Two samples of C. albicans were classified correctly, though these could have been C. glabrata (Class II). Also, one C. glabrata sample could have been classified as C. krusei (Class II). Concerning these three samples, one triplicate of each was included in Class II and two in Class I. Therefore, FT-IR associated with SIMCA can be used to identify samples of C. albicans, C. glabrata, and C. krusei grown in CHROMagar™ Candida aiming to improve clinical applications of this technique. Copyright © 2017 Elsevier B.V. All rights reserved.

Isolation of Candida Species from Gastroesophageal Lesions among Pediatrics in Isfahan, Iran: Identification and Antifungal Susceptibility Testing of Clinical Isolates by E-test

PubMed Central

Salehi, Fatemeh; Esmaeili, Mehran; Mohammadi, Rasoul

2017-01-01

Background: Candida species can become opportunistic pathogens causing local or systemic invasive infections. Gastroesophageal candidiasis may depend on the Candida colonization and local damage of the mucosal barrier. Risk factors are gastric acid suppression, diabetes mellitus, chronic debilitating states such as carcinomas, and the use of systemic antibiotics and corticosteroids. The aim of this study is collection and molecular identification of Candida species from gastroesophageal lesions among pediatrics in Isfahan, and determination of minimum inhibitory concentration (MIC) ranges for clinical isolates. Materials and Methods: A total of 200 patients underwent endoscopy (130 specimens from gastritis and 70 samples from esophagitis) were included in this study between April 2015 and November 2015. All specimens were subcultured on sabouraud dextrose agar, and genomic DNA of all strains was extracted using boiling method. Polymerase chain reaction and DNA sequencing of the ITS1-5.8SrDNA-ITS2 region were used for the identification of all Candida strains. MIC ranges were determined for itraconazole (ITC), amphotericin B (AmB), and fluconazole (FLU) by E-test. Results: Twenty of 200 suspected patients (10%) were positive by direct microscopy and culture. Candida albicans was the most common species (60%) followed by Candida glabrata (30%), Candida parapsilosis (5%), and Candida kefyr (5%). MIC ranges were determined for FLU (0.125–8 μg/mL), ITC (0.008–0.75 μg/mL), and AmB (0.008–0.75 μg/mL), respectively. Conclusion: Every colonization of Candida species should be considered as a potentially factor of mucocutaneous candidiasis and should be treated with antifungal drugs. PMID:28904931

[Study on the relationship between vaginal and intestinal candida in patients with vulvovaginal candidiasis].

PubMed

Lin, Xiao-li; Li, Zhen; Zuo, Xu-lei

2011-07-01

To investigate the relationship between vaginal and intestinal candida in patients with vulvovaginal candidiasis by using microbiological and molecular methods. The samples of vaginal discharge and anal swabs were collected from 148 cases with vulvovaginal candidiasis, followed by fungal culture, identification, purification and genome DNA extraction. The genome sequences from respective locations were aligned and typed according to their homology analyzed by internal transcribed spacer (ITS) PCR and random amplified polymorphic DNA (RAPD) PCR. Patients with vulvovaginal infection or those with infections in intestine and vulvovagina were pooled respectively, while the recurrent incidences after local anti-fungal treatments were analyzed. Candida albicans is the dominant pathogen in 148 cases with vulvovaginal candidiasis (91.9%, 136/148); 33.1% (49/148) of patients with vulvovaginal candidiasis were infected in both intestine and vulvovagina. While 92% (22/24) of patients with intestinal and vaginal candida infection showed high homology. The recurrent rate of patients with vulvovaginal candidiasis complicated with concurrent intestinal candida infection (7/14) was significantly higher than that of solo vaginal infected patients [21% (6/29)] after vaginal treatment (P<0.05). The infection of vulvovaginal candidiasis is highly associated with the concurrent infection of intestinal candida. The recurrent rate is high in patients with vulvovaginal candidiasis with concurrent infection of intestinal candida after vaginal treatment. The general management to those patients infected by both vulvovaginal and intestinal candida is necessary in reducing the recurrence of the disease.

Insights into Comparative Antimicrobial Efficacies of Synthetic and Organic Agents: The Case of ZnS Nanoparticles and Zingiber officinale Rosc.

NASA Astrophysics Data System (ADS)

Obidi, O. F.; Nejo, A. O.; Ayeni, R. A.; Revaprasadu, N.

2018-03-01

The differences among the antimicrobial activities of synthetic nanoparticles (NPs), organic agents and conventional antibiotics against human pathogens are little known. We compared the antimicrobial activities of aqueous, ethanol and ethyl acetate extracts of Zingiber officinale rhizomes with ZnS NPs and tetracycline/nystatin using agar-diffusion techniques. Transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and ultraviolet spectroscopy were used to characterize ZnS NPs. At 100 mg/ml, ethanol and ethyl acetate extract inhibited Acinetobacter baumannii, Salmonella typhimurium, Enterococcus faecium, Shigella flexneri, Klebsiella pneumoniae, Staphylococcus epidermidis and Candida albicans with zones of inhibition (ZOI) ranging between 0-42 mm and 0-39 mm, respectively. Candida albicans had a remarkable ZOI of 42 mm and 22 mm from ethanol and ZnS NPs compared with 20 mm from conventional nystatin. TEM and FTIR revealed spherically shaped polydispersed NPs with particle size of 12.5 nm and the role of banana peel extracts in ZnS NPs synthesis. Organic and synthetic NPs proved potential alternatives to conventional antimicrobial agents.

Insights into Comparative Antimicrobial Efficacies of Synthetic and Organic Agents: The Case of ZnS Nanoparticles and Zingiber officinale Rosc.

NASA Astrophysics Data System (ADS)

Obidi, O. F.; Nejo, A. O.; Ayeni, R. A.; Revaprasadu, N.

2018-06-01

The differences among the antimicrobial activities of synthetic nanoparticles (NPs), organic agents and conventional antibiotics against human pathogens are little known. We compared the antimicrobial activities of aqueous, ethanol and ethyl acetate extracts of Zingiber officinale rhizomes with ZnS NPs and tetracycline/nystatin using agar-diffusion techniques. Transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and ultraviolet spectroscopy were used to characterize ZnS NPs. At 100 mg/ml, ethanol and ethyl acetate extract inhibited Acinetobacter baumannii, Salmonella typhimurium, Enterococcus faecium, Shigella flexneri, Klebsiella pneumoniae, Staphylococcus epidermidis and Candida albicans with zones of inhibition (ZOI) ranging between 0-42 mm and 0-39 mm, respectively. Candida albicans had a remarkable ZOI of 42 mm and 22 mm from ethanol and ZnS NPs compared with 20 mm from conventional nystatin. TEM and FTIR revealed spherically shaped polydispersed NPs with particle size of 12.5 nm and the role of banana peel extracts in ZnS NPs synthesis. Organic and synthetic NPs proved potential alternatives to conventional antimicrobial agents.

Plasticity of Candida albicans Biofilms

PubMed Central

Daniels, Karla J.

2016-01-01

SUMMARY Candida albicans, the most pervasive fungal pathogen that colonizes humans, forms biofilms that are architecturally complex. They consist of a basal yeast cell polylayer and an upper region of hyphae encapsulated in extracellular matrix. However, biofilms formed in vitro vary as a result of the different conditions employed in models, the methods used to assess biofilm formation, strain differences, and, in a most dramatic fashion, the configuration of the mating type locus (MTL). Therefore, integrating data from different studies can lead to problems of interpretation if such variability is not taken into account. Here we review the conditions and factors that cause biofilm variation, with the goal of engendering awareness that more attention must be paid to the strains employed, the methods used to assess biofilm development, every aspect of the model employed, and the configuration of the MTL locus. We end by posing a set of questions that may be asked in comparing the results of different studies and developing protocols for new ones. This review should engender the notion that not all biofilms are created equal. PMID:27250770

Antifungal Effects of Saponin Extract from Rhizomes of Dioscorea panthaica Prain et Burk against Candida albicans

PubMed Central

Zhuang, Xinming; Feng, Xuechao

2018-01-01

Candida albicans is the most common fungal pathogen causing serious diseases, while there are only a paucity of antifungal drugs. Therefore, the present study was performed to investigate the antifungal effects of saponin extract from rhizomes of Dioscorea panthaica Prain et Burk (Huangshanyao Saponin extract, HSE) against C. albicans. HSE inhibits the planktonic growth and biofilm formation and development of C. albicans. 16–64 μg/mL of HSE could inhibit adhesion to polystyrene surfaces, transition from yeast to filamentous growth, and production of secreted phospholipase and could also induce endogenous reactive oxygen species (ROS) production and disrupt cell membrane in planktonic cells. Inhibitory activities against extracellular exopolysaccharide (EPS) production and ROS production in preformed biofilms could be inhibited by 64–256 μg/mL of HSE. Cytotoxicity against human Chang's liver cells is low, with a half maximal inhibitory concentration (IC50) of about 256 μg/mL. In sum, our study suggested that HSE might be used as a potential antifungal therapeutic against C. albicans. PMID:29853962

Identification of cytolytic vaginosis versus vulvovaginal candidiasis.

PubMed

Hu, Zhengqiang; Zhou, Wei; Mu, Liyuan; Kuang, Linghan; Su, Min; Jiang, Yongmei

2015-04-01

This study aimed to observe the morphological characteristic of vaginal discharge in patients with cytolytic vaginosis (CV) under the microscope and to identify it in patients with CV and in patients with vulvovaginal candidiasis (VVC). A total of 108 subjects including 21 healthy women, 33 patients with CV, and 54 patients with VVC were enrolled in the present morphological study. Vaginal discharge was collected and made into smear. The morphological characteristics of these vaginal smears with Gram staining were observed under the microscope. The smears were assessed for the quantity of lactobacilli, epithelial cell morphology, and the absence or presence of Candida species, Trichomonas vaginalis, and clue sells. First, the age, the level of education, and especially the status of pregnancy of patients with CV were significantly different from those of the patients with VVC. Second, the morphological characteristics of patients with CV consisted of overgrowth of lactobacilli, the presence of naked nuclei and fragments of the epithelial cells, a paucity of leukocytes, and the absence of Candida species and other pathogens. However, the morphological characteristic of patients with VVC consisted of the presence or absence of lactobacilli and the presence of normal epithelial cells, candidal spores, blastospores, hyphae, or other pathogens such as T. vaginalis and Gardnerella vaginalis. Both CV and VVC can be identified based on the quantity of lactobacilli, the morphology of the epithelial cells, and the absence or presence of Candida species and other pathogens, and the misdiagnosis of CV as VVC can be avoided.

Trehalose-6-Phosphate as a Potential Lead Candidate for the Development of Tps1 Inhibitors: Insights from the Trehalose Biosynthesis Pathway in Diverse Yeast Species.

PubMed

Magalhães, Rayne S S; De Lima, Karina C; de Almeida, Diego S G; De Mesquita, Joelma F; Eleutherio, Elis C A

2017-03-01

In some pathogens, trehalose biosynthesis is induced in response to stress as a protection mechanism. This pathway is an attractive target for antimicrobials as neither the enzymes, Tps1, and Tps2, nor is trehalose present in humans. Accumulation of T6P in Candida albicans, achieved by deletion of TPS2, resulted in strong reduction of fungal virulence. In this work, the effect of T6P on Tps1 activity was evaluated. Saccharomyces cerevisiae, C. albicans, and Candida tropicalis were used as experimental models. As expected, a heat stress induced both trehalose accumulation and increased Tps1 activity. However, the addition of 125 μM T6P to extracts obtained from stressed cells totally abolished or reduced in 50 and 60 % the induction of Tps1 activity in S. cerevisiae, C. tropicalis, and C. albicans, respectively. According to our results, T6P is an uncompetitive inhibitor of S. cerevisiae Tps1. This kind of inhibitor is able to decrease the rate of reaction to zero at increased concentrations. Based on the similarities found in sequence and function between Tps1 of S. cerevisiae and some pathogens and on the inhibitory effect of T6P on Tps1 activity observed in vitro, novel drugs can be developed for the treatment of infectious diseases caused by organisms whose infectivity and survival on the host depend on trehalose.

Structural and functional characterization of the recombinant thioredoxin reductase from Candida albicans as a potential target for vaccine and drug design.

PubMed

Godoy, Janine Silva Ribeiro; Kioshima, Érika Seki; Abadio, Ana Karina Rodrigues; Felipe, Maria Sueli Soares; de Freitas, Sonia Maria; Svidzinski, Terezinha Inez Estivalet

2016-05-01

The thioredoxin system plays a critical role in maintaining the cytoplasm redox state, participating in functions that are important to the cellular viability of fungi. Although functional and structural information on targets in human pathogenic fungi has been scarcely described in the literature, such studies are essential for in silico drug design and biotechnological applications. Therefore, the aims of the present study were to produce recombinant proteins of the thioredoxin system from Candida albicans and evaluate their possible use as prophylactic or alternative therapies against the most important pathogenic fungus associated with nosocomial infections. We focused on biochemical and structural analyses of recombinant thioredoxin reductase from C. albicans with His-tag (CaTrxR-His) for further biotechnology applications. Heterologous CaTrxR-His was efficiently expressed in the soluble fraction of the Escherichia coli lysate. CaTrxR-His was obtained with a high level of purity and presented specific enzymatic activity. Conformational changes of the protein were observed at different pHs and temperatures, with higher thermal stability at pH 8.0. The CaTrxR-His vaccine was shown to effectively induce high levels of CaTrxR-specific immunoglobulin G antibodies in Balb/c mice and reduce the renal fungal burden of experimental disseminated candidiasis in mice. These data may greatly impact future development strategies for vaccine and drug designs against C. albicans infection.

Growth, biofilm formation, antifungal susceptibility and oxidative stress resistance of Candida glabrata are affected by different glucose concentrations.

PubMed

Ng, Tzu Shan; Desa, Mohd Nasir Mohd; Sandai, Doblin; Chong, Pei Pei; Than, Leslie Thian Lung

2016-06-01

Glucose is an important fuel source to support many living organisms. Its importance in the physiological fitness and pathogenicity of Candida glabrata, an emerging human fungal pathogen has not been extensively studied. The present study aimed to investigate the effects of glucose on the growth, biofilm formation, antifungal susceptibility and oxidative stress resistance of C. glabrata. In addition, its effect on the expression of a putative high affinity glucose sensor gene, SNF3 was also investigated. Glucose concentrations were found to exert effects on the physiological responses of C. glabrata. The growth rate of the species correlated positively to the amount of glucose. In addition, low glucose environments were found to induce C. glabrata to form biofilm and resist amphotericin B. Conversely, high glucose environments promoted oxidative stress resistance of C. glabrata. The expression of CgSNF3 was found to be significantly up-regulated in low glucose environments. The expression of SNF3 gene in clinical isolates was found to be higher compared to ATCC laboratory strains in low glucose concentrations, which may explain the better survivability of clinical isolates in the low glucose environment. These observations demonstrated the impact of glucose in directing the physiology and virulence fitness of C. glabrata through the possible modulation by SNF3 as a glucose sensor, which in turn aids the species to adapt, survive and thrive in hostile host environment. Copyright © 2015 Elsevier B.V. All rights reserved.

Genetic and phenotypic intra-species variation in Candida albicans

PubMed Central

Hirakawa, Matthew P.; Martinez, Diego A.; Sakthikumar, Sharadha; Anderson, Matthew Z.; Berlin, Aaron; Gujja, Sharvari; Zeng, Qiandong; Zisson, Ethan; Wang, Joshua M.; Greenberg, Joshua M.; Berman, Judith

2015-01-01

Candida albicans is a commensal fungus of the human gastrointestinal tract and a prevalent opportunistic pathogen. To examine diversity within this species, extensive genomic and phenotypic analyses were performed on 21 clinical C. albicans isolates. Genomic variation was evident in the form of polymorphisms, copy number variations, chromosomal inversions, subtelomeric hypervariation, loss of heterozygosity (LOH), and whole or partial chromosome aneuploidies. All 21 strains were diploid, although karyotypic changes were present in eight of the 21 isolates, with multiple strains being trisomic for Chromosome 4 or Chromosome 7. Aneuploid strains exhibited a general fitness defect relative to euploid strains when grown under replete conditions. All strains were also heterozygous, yet multiple, distinct LOH tracts were present in each isolate. Higher overall levels of genome heterozygosity correlated with faster growth rates, consistent with increased overall fitness. Genes with the highest rates of amino acid substitutions included many cell wall proteins, implicating fast evolving changes in cell adhesion and host interactions. One clinical isolate, P94015, presented several striking properties including a novel cellular phenotype, an inability to filament, drug resistance, and decreased virulence. Several of these properties were shown to be due to a homozygous nonsense mutation in the EFG1 gene. Furthermore, loss of EFG1 function resulted in increased fitness of P94015 in a commensal model of infection. Our analysis therefore reveals intra-species genetic and phenotypic differences in C. albicans and delineates a natural mutation that alters the balance between commensalism and pathogenicity. PMID:25504520

Candida albicans Impairments Induced by Peppermint and Clove Oils at Sub-Inhibitory Concentrations

PubMed Central

Rajkowska, Katarzyna; Otlewska, Anna; Kunicka-Styczyńska, Alina; Krajewska, Agnieszka

2017-01-01

Members of Candida species cause significant health problems, inducing various types of superficial and deep-seated mycoses in humans. In order to prevent from Candida sp. development, essential oils are more and more frequently applied, due to their antifungal activity, low toxicity if used appropriately, and biodegrability. The aim of the study was to characterize the early alterations in Candida albicans metabolic properties in relation to proteins and chromosomal DNA profiles, after treatment with peppermint and clove oils at sub-inhibitory concentrations. The yeasts were affected by the oils even at a concentration of 0.0075% v/v, which resulted in changes in colony morphotypes and metabolic activities. Peppermint and clove oils at concentrations ranging from 0.015× MIC (minimal inhibitory concentration) to 0.5× MIC values substantially affected the enzymatic abilities of C. albicans, and these changes were primarily associated with the loss or decrease of activity of all 9 enzymes detected in the untreated yeast. Moreover, 29% isolates showed additional activity of N-acetyl-β-glucosaminidase and 14% isolates—α-fucosidase in comparison to the yeast grown without essential oils addition. In response to essential oils at 0.25–0.5× MIC, extensive changes in C. albicans whole-cell protein profiles were noted. However, the yeast biochemical profiles were intact with the sole exception of the isolate treated with clove oil at 0.5× MIC. The alterations were not attributed to gross chromosomal rearrangements in C. albicans karyotype. The predominantly observed decrease in protein fractions and the yeast enzymatic activity after treatment with the oils should be considered as a phenotypic response of C. albicans to the essential oils at their sub-inhibitory concentrations and may lead to the reduction of this yeast pathogenicity. PMID:28629195

Candida albicans Impairments Induced by Peppermint and Clove Oils at Sub-Inhibitory Concentrations.

PubMed

Rajkowska, Katarzyna; Otlewska, Anna; Kunicka-Styczyńska, Alina; Krajewska, Agnieszka

2017-06-19

Members of Candida species cause significant health problems, inducing various types of superficial and deep-seated mycoses in humans. In order to prevent from Candida sp. development, essential oils are more and more frequently applied, due to their antifungal activity, low toxicity if used appropriately, and biodegrability. The aim of the study was to characterize the early alterations in Candida albicans metabolic properties in relation to proteins and chromosomal DNA profiles, after treatment with peppermint and clove oils at sub-inhibitory concentrations. The yeasts were affected by the oils even at a concentration of 0.0075% v / v , which resulted in changes in colony morphotypes and metabolic activities. Peppermint and clove oils at concentrations ranging from 0.015× MIC (minimal inhibitory concentration) to 0.5× MIC values substantially affected the enzymatic abilities of C. albicans , and these changes were primarily associated with the loss or decrease of activity of all 9 enzymes detected in the untreated yeast. Moreover, 29% isolates showed additional activity of N -acetyl-β-glucosaminidase and 14% isolates-α-fucosidase in comparison to the yeast grown without essential oils addition. In response to essential oils at 0.25-0.5× MIC, extensive changes in C. albicans whole-cell protein profiles were noted. However, the yeast biochemical profiles were intact with the sole exception of the isolate treated with clove oil at 0.5× MIC. The alterations were not attributed to gross chromosomal rearrangements in C. albicans karyotype. The predominantly observed decrease in protein fractions and the yeast enzymatic activity after treatment with the oils should be considered as a phenotypic response of C. albicans to the essential oils at their sub-inhibitory concentrations and may lead to the reduction of this yeast pathogenicity.

Stability and resilience of oral microcosms toward acidification and Candida outgrowth by arginine supplementation.

PubMed

Koopman, Jessica E; Röling, Wilfred F M; Buijs, Mark J; Sissons, Christopher H; ten Cate, Jacob M; Keijser, Bart J F; Crielaard, Wim; Zaura, Egija

2015-02-01

Dysbiosis induced by low pH in the oral ecosystem can lead to caries, a prevalent bacterial disease in humans. The amino acid arginine is one of the pH-elevating agents in the oral cavity. To obtain insights into the effect of arginine on oral microbial ecology, a multi-plaque "artificial mouth" (MAM) biofilm model was inoculated with saliva from a healthy volunteer and microcosms were grown for 4 weeks with 1.6 % (w/v) arginine supplement (Arginine) or without (Control), samples were taken at several time-points. A cariogenic environment was mimicked by sucrose pulsing. The bacterial composition was determined by 16S rRNA gene amplicon sequencing, the presence and amount of Candida and arginine deiminase system genes arcA and sagP by qPCR. Additionally, ammonium and short-chain fatty acid concentrations were determined. The Arginine microcosms were dominated by Streptococcus, Veillonella, and Neisseria and remained stable in time, while the composition of the Control microcosms diverged significantly in time, partially due to the presence of Megasphaera. The percentage of Candida increased 100-fold in the Control microcosms compared to the Arginine microcosms. The pH-raising effect of arginine was confirmed by the pH and ammonium results. The abundances of sagP and arcA were highest in the Arginine microcosms, while the concentration of butyrate was higher in the Control microcosms. We demonstrate that supplementation with arginine serves a health-promoting function; it enhances microcosm resilience toward acidification and suppresses outgrowth of the opportunistic pathogen Candida. Arginine facilitates stability of oral microbial communities and prevents them from becoming cariogenic.

Emerging IL-12 family cytokines in the fight against fungal infections.

PubMed

Thompson, Aiysha; Orr, Selinda J

2018-05-21

Invasive fungal infections cause approximately 1.5 million deaths per year worldwide and are a growing threat to human health. Current anti-fungal therapies are often insufficient, therefore studies into host-pathogen interactions are critical for the development of novel therapies to improve mortality rates. Myeloid cells, such as macrophages and dendritic cells, express pattern recognition receptor (PRRs), which are important for fungal recognition. Engagement of these PRRs by fungal pathogens induces multiple cytokines, which in turn activate T effector responses. Interleukin (IL)-12 family members (IL-12p70, IL-23, IL-27 and IL-35) link innate immunity with the development of adaptive immunity and are also important for regulating T cell responses. IL-12 and IL-23 have established roles during anti-fungal immunity, whereas emerging roles for IL-27 and IL-35 have recently been reported. Here, we discuss the IL-12 family, focusing on IL-27 and IL-35 during anti-fungal immune responses to pathogens such as Candida and Aspergillus. Copyright © 2018. Published by Elsevier Ltd.

Secretory Aspartyl Proteinases Cause Vaginitis and Can Mediate Vaginitis Caused by Candida albicans in Mice

PubMed Central

Pericolini, Eva; Gabrielli, Elena; Amacker, Mario; Kasper, Lydia; Roselletti, Elena; Luciano, Eugenio; Sabbatini, Samuele; Kaeser, Matthias; Moser, Christian; Hube, Bernhard; Vecchiarelli, Anna

2015-01-01

ABSTRACT Vaginal inflammation (vaginitis) is the most common disease caused by the human-pathogenic fungus Candida albicans. Secretory aspartyl proteinases (Sap) are major virulence traits of C. albicans that have been suggested to play a role in vaginitis. To dissect the mechanisms by which Sap play this role, Sap2, a dominantly expressed member of the Sap family and a putative constituent of an anti-Candida vaccine, was used. Injection of full-length Sap2 into the mouse vagina caused local neutrophil influx and accumulation of the inflammasome-dependent interleukin-1β (IL-1β) but not of inflammasome-independent tumor necrosis factor alpha. Sap2 could be replaced by other Sap, while no inflammation was induced by the vaccine antigen, the N-terminal-truncated, enzymatically inactive tSap2. Anti-Sap2 antibodies, in particular Fab from a human combinatorial antibody library, inhibited or abolished the inflammatory response, provided the antibodies were able, like the Sap inhibitor Pepstatin A, to inhibit Sap enzyme activity. The same antibodies and Pepstatin A also inhibited neutrophil influx and cytokine production stimulated by C. albicans intravaginal injection, and a mutant strain lacking SAP1, SAP2, and SAP3 was unable to cause vaginal inflammation. Sap2 induced expression of activated caspase-1 in murine and human vaginal epithelial cells. Caspase-1 inhibition downregulated IL-1β and IL-18 production by vaginal epithelial cells, and blockade of the IL-1β receptor strongly reduced neutrophil influx. Overall, the data suggest that some Sap, particularly Sap2, are proinflammatory proteins in vivo and can mediate the inflammasome-dependent, acute inflammatory response of vaginal epithelial cells to C. albicans. These findings support the notion that vaccine-induced or passively administered anti-Sap antibodies could contribute to control vaginitis. PMID:26037125

Detection of human Pneumocystis carinii by the polymerase chain reaction.

PubMed

Becker-Hapak, M; Liberator, P; Graves, D

1991-01-01

Oligonucleotide primers were prepared from a clone (B12) which has been shown to be a repetitive sequence in the rat P. carinii genome. Polymerase chain reaction was employed to amplify both rat and human P. carinii DNA. The detection limit of the assay was approximately 600 ng of total nucleic acid. Amplification products from both the rat and human isolates (ca. 780 bp) were characterized by denaturing gradient gel electrophoresis after digestion with Sau3A. No amplification products were obtained when DNA from the following potential pulmonary pathogens were used in identical reactions: Aspergillus fumigatus, Cryptococcus neoformans, Candida albicans, Mycobacterium avium-intracellulare and cytomegalovirus. In a blind study using the B12 primers, P. carinii DNA was successfully amplified in clinical samples which were positive by direct immunofluorescence assay (IFA) as well as in some specimens not identified by direct IFA.

Use of chlorhexidine gel (0.2%) to control gingivitis and candida species colonization in human immunodeficiency virus-infected children: a pilot study.

PubMed

Machado, Fernanda Campos; de Souza, Ivete Pomarico Ribeiro; Portela, Maristela Barbosa; de Araújo Soares, Rosangela Maria; Freitas-Fernandes, Liana Bastos; Castro, Gloria Fernanda

2011-01-01

The purpose of this study was to evaluate chlorhexidine to control gingivitis and Candida species (spp.) in children infected with the human immunodeficiency virus (HIV) and their acceptance of the therapy. Twenty-six HIV+ children were selected, and oral exam-established biofilm, gingival indexes, and stimulated saliva were collected for Candida ssp. identification. The children brushed their teeth for 21 days with chlorhexidine gel (0.2%). Salivary samples, biofilm, and gingival indexes were collected after 21-days and again 35 days after ceasing gel use. The children answered a questionnaire about the therapy. All children tested positive for Candida and gingivitis. After 21 days, Candida counts and gingivitis decreased in 25 and 26 children, respectively. Mean reduction was approximately 68% for Candida spp. and 74% for gingivitis. Thirty-five days after discontinuing gel use, gingivitis and Candida spp. increased in 13 and 16 patients, respectively. Considering the Candida spp., the heavy growth was lower in the first re-evaluation. Candida albicans was the most frequent species. Approximately 85% did not experience inconvenience with the gel, and approximately 48% thought it was good for tooth-brushing. Chlorhexidine therapy may be an option to treat and pre- vent gingivitis and reduce yeast counts in children infected with HIV.

Candida tropicalis biofilm and human epithelium invasion is highly influenced by environmental pH.

PubMed

Ferreira, Carina; Gonçalves, Bruna; Vilas Boas, Diana; Oliveira, Hugo; Henriques, Mariana; Azeredo, Joana; Silva, Sónia

2016-11-01

The main goal of this study was to investigate the role of pH on Candida tropicalis virulence determinants, namely the ability to form biofilms and to colonize/invade reconstituted human vaginal epithelia. Biofilm formation was evaluated by enumeration of cultivable cells, total biomass quantification and structural analysis by scanning electron microscopy and confocal laser scanning microscopy. Candida tropicalis human vaginal epithelium colonization and invasiveness were examined qualitatively by epifluorescence microscopy and quantitatively by a novel quantitative real-time PCR protocol for Candida quantification in tissues. The results revealed that environmental pH influences C. tropicalis biofilm formation as well as the colonization and potential to invade human epithelium with intensification at neutral and alkaline conditions compared to acidic conditions. For the first time, we have demonstrated that C. tropicalis biofilm formation and invasion is highly influenced by environmental pH. © Crown copyright 2016.

Evaluation of CAMP-Like Effect, Biofilm Formation, and Discrimination of Candida africana from Vaginal Candida albicans Species

PubMed Central

Bordbar, Mahboubeh; Nouraei, Hasti; Khodadadi, Hossein

2017-01-01

Candida africana as a species recovered from female genital specimens is highly close to C. albicans. The present study was conducted to discriminate C. africana from presumptive vaginal C. albicans strains by molecular assay and evaluate their hemolysin activity, biofilm formation, and cohemolytic effect (CAMP) with vaginal bacterial flora. A total of 110 stock vaginal C. albicans isolates were examined by HWP1 gene amplification. Hemolysin activity and the ability of biofilm formation were evaluated by blood plate assay and visual detection methods, respectively. Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus agalactiae were used to evaluate the CAMP-like effects in Sabouraud blood agar media. Based on the size of the amplicons (941 bp), all isolates were identified as C. albicans. All samples were able to produce beta-hemolysin. Moreover, 69 out of 110 of the isolates (62.7%) were biofilm-positive, 54 out of 110 Candida isolates (49%) demonstrated cohemolytic effects with S. agalactiae, and 48 out of 110 showed this effect with S. aureus (43.6%). All isolates were CAMP-negative with S. epidermidis. We detected all isolates as Candida albicans and almost half of the isolates were CAMP-positive with S. aureus and S. agalactiae, suggesting that these bacteria increase the pathogenicity of Candida in vaginal candidiasis. PMID:29318048

[Candida biofilm-related infections].

PubMed

Del Pozo, José Luis; Cantón, Emilia

2016-01-01

The number of biomedical devices (intravascular catheters, heart valves, joint replacements, etc.) that are implanted in our hospitals has increased exponentially in recent years. Candida species are pathogens which are becoming more significant in these kinds of infections. Candida has two forms of development: planktonic and in biofilms. A biofilm is a community of microorganisms which adhere to a surface and are enclosed by an extracellular matrix. This form of development confers a high resistance to the antimicrobial agents. This is the reason why antibiotic treatments usually fail and biomedical devices may have to be removed in most cases. Unspecific adhesion mechanisms, the adhesion-receptor systems, and an intercellular communication system called quorum sensing play an essential role in the development of Candida biofilms. In general, the azoles have poor activity against Candida biofilms, while echinocandins and polyenes show a greater activity. New therapeutic strategies need to be developed due to the high morbidity and mortality and high economic costs associated with these infections. Most studies to date have focused on bacterial biofilms. The knowledge of the formation of Candida biofilms and their composition is essential to develop new preventive and therapeutic strategies. Copyright © 2014 Asociación Española de Micología. Publicado por Elsevier España, S.L.U. All rights reserved.

Culture media profoundly affect Candida albicans and Candida tropicalis growth, adhesion and biofilm development.

PubMed

Weerasekera, Manjula M; Wijesinghe, Gayan K; Jayarathna, Thilini A; Gunasekara, Chinthika P; Fernando, Neluka; Kottegoda, Nilwala; Samaranayake, Lakshman P

2016-11-01

As there are sparse data on the impact of growth media on the phenomenon of biofilm development for Candida we evaluated the efficacy of three culture media on growth, adhesion and biofilm formation of two pathogenic yeasts, Candida albicans and Candida tropicalis. The planktonic phase yeast growth, either as monocultures or mixed cultures, in sabouraud dextrose broth (SDB), yeast nitrogen base (YNB), and RPMI 1640 was compared, and adhesion as well as biofilm formation were monitored using MTT and crystal violet (CV) assays and scanning electron microscopy. Planktonic cells of C. albicans, C. tropicalis and their 1:1 co-culture showed maximal growth in SDB. C. albicans/C. tropicalis adhesion was significantly facilitated in RPMI 1640 although the YNB elicited the maximum growth for C. tropicalis. Similarly, the biofilm growth was uniformly higher for both species in RPMI 1640, and C. tropicalis was the slower biofilm former in all three media. Scanning electron microscopy images tended to confirm the results of MTT and CV assay. Taken together, our data indicate that researchers should pay heed to the choice of laboratory culture media when comparing relative planktonic/biofilm growth of Candida. There is also a need for standardisation of biofilm development media so as to facilitate cross comparisons between laboratories.

Selective induction of phospholipase D1 in pathogen-activated human monocytes.

PubMed

Locati, M; Riboldi, E; Bonecchi, R; Transidico, P; Bernasconi, S; Haribabu, B; Morris, A J; Mantovani, A; Sozzani, S

2001-08-15

Phospholipase D (PLD) activation is part of the complex signalling cascade induced during phagocyte activation. Two PLD isoforms have been cloned, but their role in phagocyte functions is still poorly defined. We report that resting fresh circulating human monocytes expressed PLD1. PLD1 protein expression was rapidly down-regulated during cell culture. Lipopolysaccharide and pathogen-derived agonists (Candida albicans, arabinoside-terminated lipoarabinomannan and Gram-positive bacteria, but not mannose-capped lipoarabinomannan or double-stranded RNA) strongly induced PLD1 expression at both the mRNA and protein levels. Pro-inflammatory cytokines [interleukin (IL)-1beta and tumour necrosis factor alpha] had only a weak effect, whereas immune cytokines (IL-6 and interferon gamma), anti-inflammatory cytokines (IL-13 and IL-10) and chemoattractants (fMet-Leu-Phe and macrophage chemoattractant protein 1) were inactive. None of the agonists tested induced significant changes in the basal expression of PLD2 mRNA. Consistent with PLD1 up-regulation was the observation that PLD enzymic activity was higher in monocytes treated with active-pathogen-derived agonists than in control cells, when stimulated with PMA or with chemotactic agonists (fMet-Leu-Phe and C5a). Thus PLD2 seems to be a constitutive enzyme in circulating monocytes. Conversely, PLD1 is an inducible protein, rapidly regulated during culture conditions and selectively induced during cell activation. Therefore PLD1 might have a relevant role in immune responses against pathogens and in chronic inflammation.

PF1163A and B, new antifungal antibiotics produced by Penicillium sp. I. Taxonomy of producing strain, fermentation, isolation and biological activities.

PubMed

Nose, H; Seki, A; Yaguchi, T; Hosoya, A; Sasaki, T; Hoshiko, S; Shomura, T

2000-01-01

Two novel antifungal antibiotics, PF1163A and B, were isolated from the fermentation broth of Penicillium sp. They were purified from the solid cultures of rice media using ethyl acetate extraction, silica gel and Sephadex LH-20 column chromatographies. PF1163A and B showed potent growth inhibitory activity against pathogenic fungal strain Candida albicans but did not show cytotoxic activity against mammalian cells. These compounds inhibited the ergosterol biosynthesis in Candida albicans.

[Infectious risk related to the formation of multi-species biofilms (Candida - bacteria) on peripheral vascular catheters].

PubMed

Seghir, A; Boucherit-Otmani, Z; Sari-Belkharroubi, L; Boucherit, K

2017-03-01

The Candida yeasts are the fourth leading cause of death from systemic infections, the risk may increase when the infection also involves bacteria. Yeasts and bacteria can adhere to medical implants, such as peripheral vascular catheters, and form a multicellular structures called "mixed biofilms" more resistant to antimicrobials agents. However, the formation of mixed biofilms on implants leads to long-term persistent infections because they can act as reservoirs of pathogens that have poorly understood interactions. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Identification of infection- and defense-related genes via a dynamic host-pathogen interaction network using a Candida albicans-zebrafish infection model.

PubMed

Kuo, Zong-Yu; Chuang, Yung-Jen; Chao, Chun-Cheih; Liu, Fu-Chen; Lan, Chung-Yu; Chen, Bor-Sen

2013-01-01

Candida albicans infections and candidiasis are difficult to treat and create very serious therapeutic challenges. In this study, based on interactive time profile microarray data of C. albicans and zebrafish during infection, the infection-related protein-protein interaction (PPI) networks of the two species and the intercellular PPI network between host and pathogen were simultaneously constructed by a dynamic interaction model, modeled as an integrated network consisting of intercellular invasion and cellular defense processes during infection. The signal transduction pathways in regulating morphogenesis and hyphal growth of C. albicans were further investigated based on significant interactions found in the intercellular PPI network. Two cellular networks were also developed corresponding to the different infection stages (adhesion and invasion), and then compared with each other to identify proteins from which we can gain more insight into the pathogenic role of hyphal development in the C. albicans infection process. Important defense-related proteins in zebrafish were predicted using the same approach. The hyphal growth PPI network, zebrafish PPI network and host-pathogen intercellular PPI network were combined to form an integrated infectious PPI network that helps us understand the systematic mechanisms underlying the pathogenicity of C. albicans and the immune response of the host, and may help improve medical therapies and facilitate the development of new antifungal drugs. Copyright © 2013 S. Karger AG, Basel.

Human vaginal epithelial cells augment autophagy marker genes in response to Candida albicans infection.

PubMed

Shroff, Ankit; Sequeira, Roicy; Reddy, Kudumula Venkata Rami

2017-04-01

Autophagy plays an important role in clearance of intracellular pathogens. However, no information is available on its involvement in vaginal infections such as vulvo-vaginal candidiasis (VVC). VVC is intimately associated with the immune status of the human vaginal epithelial cells (VECs). The objective of our study is to decipher if autophagy process is involved during Candida albicans infection of VECs. In this study, C. albicans infection system was established using human VEC line (VK2/E6E7). Infection-induced change in the expression of autophagy markers like LC3 and LAMP-1 were analyzed by RT-PCR, q-PCR, Western blot, immunofluorescence and transmission electron microscopy (TEM) studies were carried out to ascertain the localization of autophagosomes. Multiplex ELISA was carried out to determine the cytokine profiles. Analysis of LC3 and LAMP-1 expression at mRNA and protein levels at different time points revealed up-regulation of these markers 6 hours post C. albicans infection. LC3 and LAMP-1 puncti were observed in infected VECs after 12 hours. TEM studies showed C. albicans entrapped in autophagosomes. Cytokines-TNF-α and IL-1β were up-regulated in culture supernatants of VECs at 12 hours post-infection. The results suggest that C. albicans invasion led to the activation of autophagy as a host defense mechanism of VECs. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Isolation of Candida dubliniensis for the first time in Cali, Colombia, and its identification with phenotyping methods.

PubMed

Alvarez, María Inés; Suárez, Blanca Lynne; Caicedo, Luz Dary

2009-01-01

Candida dubliniensis is an emerging pathogenic yeast isolated mainly from the oral cavity of HIV-infected patients. The close phenotypic and genotypic relationship between C. albicans and C. dubliniensis has led to incorrectly identifying isolates of C. dubliniensis as C. albicans. The oral cavities of 107 diabetic patients were studied in Cali, Colombia, and 72 colonies of Candida, with shades of green on CHROMagar Candida culture media, were obtained. Various phenotypic tests were carried out, which included germ tube formation and production of chlamydospores on corn meal Agar. Additionally, growth studies were carried out at 42 degrees C and 45 degrees C and on Sabouraud agar with 6.5%, sodium chloride. Identification of C. dubliniensis with these tests was confirmed with API 20C Aux. We identified 65 and 7 colonies of C. albicans and C. dubliniensis, respectively. This is the first time that C. dubliniensis is identified with phenotypic methods in Colombia.

Prevalence of Candida albicans, Candida dubliniensis and Candida africana in pregnant women suffering from vulvovaginal candidiasis in Argentina.

PubMed

Mucci, María Josefina; Cuestas, María Luján; Landanburu, María Fernanda; Mujica, María Teresa

Vulvovaginal candidiasis (VVC) is a vulvovaginitis commonly diagnosed in gynecology care. In recent years, the taxonomy of the most important pathogenic Candida species, such as Candida albicans have undergone significant changes. This study examined the prevalence of C. albicans, Candida africana, and Candida dubliniensis in vaginal specimens from 210 pregnant women suffering from vulvovaginitis or having asymptomatic colonization. Phenotypic and molecular methods were used for the identification of the species. During the studied period, 55 isolates of Candida or other yeasts were obtained from specimens collected from 52 patients suffering from vulvovaginitis (24.8%). C. albicans was the predominant Candida species in 42 isolates (80.7%), either alone or in combination with other species of the genus (5.7%, n=3). Additionally, nine isolates of C. albicans (50%) were obtained from asymptomatic patients (n=18). C. dubliniensis was the causative agent in 2 (3.8%) cases of VVC, and was also isolated in one asymptomatic patient. Molecular assays were carried out using specific PCR to amplify the ACT1-associated intron sequence of C. dubliniensis. The amplification of the HWP1 gene also correctly identified isolates of the species C. albicans and C. dubliniensis. No C. africana was isolated in this work. Some C. albicans isolates were either homozygous or heterozygous at the HWP1 locus. The distribution of heterozygous and homozygous C. albicans isolates at the HWP1 locus was very similar among patients suffering from VVC and asymptomatic patients (p=0.897). The presence of C. albicans and C. dubliniensis, and the absence of C. africana in pregnant is noteworthy. Copyright © 2016 Asociación Española de Micología. Publicado por Elsevier España, S.L.U. All rights reserved.

Rapid identification of fungal pathogens in BacT/ALERT, BACTEC, and BBL MGIT media using polymerase chain reaction and DNA sequencing of the internal transcribed spacer regions.

PubMed

Pryce, Todd M; Palladino, Silvano; Price, Diane M; Gardam, Dianne J; Campbell, Peter B; Christiansen, Keryn J; Murray, Ronan J

2006-04-01

We report a direct polymerase chain reaction/sequence (d-PCRS)-based method for the rapid identification of clinically significant fungi from 5 different types of commercial broth enrichment media inoculated with clinical specimens. Media including BacT/ALERT FA (BioMérieux, Marcy l'Etoile, France) (n = 87), BACTEC Plus Aerobic/F (Becton Dickinson, Microbiology Systems, Sparks, MD) (n = 16), BACTEC Peds Plus/F (Becton Dickinson) (n = 15), BACTEC Lytic/10 Anaerobic/F (Becton Dickinson) (n = 11) bottles, and BBL MGIT (Becton Dickinson) (n = 11) were inoculated with specimens from 138 patients. A universal DNA extraction method was used combining a novel pretreatment step to remove PCR inhibitors with a column-based DNA extraction kit. Target sequences in the noncoding internal transcribed spacer regions of the rRNA gene were amplified by PCR and sequenced using a rapid (24 h) automated capillary electrophoresis system. Using sequence alignment software, fungi were identified by sequence similarity with sequences derived from isolates identified by upper-level reference laboratories or isolates defined as ex-type strains. We identified Candida albicans (n = 14), Candida parapsilosis (n = 8), Candida glabrata (n = 7), Candida krusei (n = 2), Scedosporium prolificans (n = 4), and 1 each of Candida orthopsilosis, Candida dubliniensis, Candida kefyr, Candida tropicalis, Candida guilliermondii, Saccharomyces cerevisiae, Cryptococcus neoformans, Aspergillus fumigatus, Histoplasma capsulatum, and Malassezia pachydermatis by d-PCRS analysis. All d-PCRS identifications from positive broths were in agreement with the final species identification of the isolates grown from subculture. Earlier identification of fungi using d-PCRS may facilitate prompt and more appropriate antifungal therapy.

Performance of CHROMAGAR candida and BIGGY agar for identification of yeast species.

PubMed

Yücesoy, Mine; Marol, Serhat

2003-10-29

The importance of identifying the pathogenic fungi rapidly has encouraged the development of differential media for the presumptive identification of yeasts. In this study two differential media, CHROMagar Candida and bismuth sulphite glucose glycine yeast agar, were evaluated for the presumptive identification of yeast species. A total number of 270 yeast strains including 169 Candida albicans, 33 C. tropicalis, 24 C. glabrata, 18 C. parapsilosis, 12 C. krusei, 5 Trichosporon spp., 4 C. kefyr, 2 C. lusitaniae, 1 Saccharomyces cerevisiae and 1 Geotrichum candidum were included. The strains were first identified by germ tube test, morphological characteristics on cornmeal tween 80 agar and Vitek 32 and API 20 C AUX systems. In parallel, they were also streaked onto CHROMagar Candida and bismuth sulphite glucose glycine yeast agar plates. The results were read according to the color, morphology of the colonies and the existance of halo around them after 48 hours of incubation at 37 degrees C. The sensitivity and specificity values for C. albicans strains were found to be 99.4, 100% for CHROMagar Candida and 87.0, 75.2% for BiGGY agar, respectively. The sensitivity of CHROMagar Candida to identify C. tropicalis, C. glabrata and C. krusei ranged between 90.9 and 100% while the specificity was 100%. The sensitivity rates for BiGGY agar were 66.6 and 100% while the specificity values were found to be 95.4 and 100% for C. tropicalis and C. krusei, respectively. It can be concluded that the use of CHROMagar Candida is an easy and reliable method for the presumptive identification of most commonly isolated Candida species especially C. albicans, C. tropicalis and C. krusei. The lower sensitivity and specificity of BiGGY agar to identify commonly isolated Candida species potentially limits the clinical usefulness of this agar.

Tissue-Resident Macrophages in Fungal Infections.

PubMed

Xu, Shengjie; Shinohara, Mari L

2017-01-01

Invasive fungal infections result in high morbidity and mortality. Host organs targeted by fungal pathogens vary depending on the route of infection and fungal species encountered. Cryptococcus neoformans infects the respiratory tract and disseminates throughout the central nervous system. Candida albicans infects mucosal tissues and the skin, and systemic Candida infection in rodents has a tropism to the kidney. Aspergillus fumigatus reaches distal areas of the lung once inhaled by the host. Across different tissues in naïve hosts, tissue-resident macrophages (TRMs) are one of the most populous cells of the innate immune system. Although they function to maintain homeostasis in a tissue-specific manner during steady state, TRMs may function as the first line of defense against invading pathogens and may regulate host immune responses. Thus, in any organs, TRMs are uniquely positioned and specifically programmed to function. This article reviews the current understanding of the roles of TRMs during major fungal infections.

Multidrug-Resistant Candida haemulonii and C. auris, Tel Aviv, Israel.

PubMed

Ben-Ami, Ronen; Berman, Judith; Novikov, Ana; Bash, Edna; Shachor-Meyouhas, Yael; Zakin, Shiri; Maor, Yasmin; Tarabia, Jalal; Schechner, Vered; Adler, Amos; Finn, Talya

2017-02-01

Candida auris and C. haemulonii are closely related, multidrug-resistant emerging fungal pathogens that are not readily distinguishable with phenotypic assays. We studied C. auris and C. haemulonii clinical isolates from 2 hospitals in central Israel. C. auris was isolated in 5 patients with nosocomial bloodstream infection, and C. haemulonii was found as a colonizer of leg wounds at a peripheral vascular disease clinic. Liberal use of topical miconazole and close contact among patients were implicated in C. haemulonii transmission. C. auris exhibited higher thermotolerance, virulence in a mouse infection model, and ATP-dependent drug efflux activity than C. haemulonii. Comparison of ribosomal DNA sequences found that C. auris strains from Israel were phylogenetically distinct from isolates from East Asia, South Africa and Kuwait, whereas C. haemulonii strains from different countries were closely interrelated. Our findings highlight the pathogenicity of C. auris and underscore the need to limit its spread.

Pathogenic Gut Flora in Patients With Chronic Heart Failure.

PubMed

Pasini, Evasio; Aquilani, Roberto; Testa, Cristian; Baiardi, Paola; Angioletti, Stefania; Boschi, Federica; Verri, Manuela; Dioguardi, Francesco

2016-03-01

The goal of this study was to measure the presence of pathogenic gut flora and intestinal permeability (IP) and their correlations with disease severity, venous blood congestion, and inflammation in patients with chronic heart failure (CHF). Evidence suggests that translocation of gut flora and/or their toxins from the intestine to the bloodstream is a possible trigger of systemic CHF inflammation. However, the relation between pathogenic gut flora and CHF severity, as well as IP, venous blood congestion as right atrial pressure (RAP), and/or systemic inflammation (C-reactive protein [CRP]), is still unknown. This study analyzed 60 well-nourished patients in stable condition with mild CHF (New York Heart Association [NYHA] functional class I to II; n = 30) and moderate to severe CHF (NYHA functional class III to IV; n = 30) and matched healthy control subjects (n = 20). In all subjects, the presence and development in the feces of bacteria and fungi (Candida species) were measured; IP according to cellobiose sugar test results was documented. The study data were then correlated with RAP (echocardiography) and systemic inflammation. Compared with normal control subjects, the entire CHF population had massive quantities of pathogenic bacteria and Candida such as Campylobacter (85.3 ± 3.7 CFU/ml vs. 1.0 ± 0.3 CFU/ml; p < 0.001), Shigella (38.9 ± 12.3 CFU/ml vs. 1.6 ± 0.2 CFU/ml; p < 0.001), Salmonella (31.3 ± 9.1 CFU/ml vs 0 CFU/ml; p < 0.001), Yersinia enterocolitica (22.9 ± 6.3 CFU/ml vs. 0 CFU/ml; p < 0.0001), and Candida species (21.3 ± 1.6 CFU/ml vs. 0.8 ± 0.4 CFU/ml; p < 0.001); altered IP (10.2 ± 1.2 mg vs. 1.5 ± 0.8 mg; p < 0.001); and increased RAP (12.6 ± 0.6 mm Hg) and inflammation (12.5 ± 0.6 mg/dl). These variables were more pronounced in patients with moderate to severe NYHA functional classes than in patients with the mild NYHA functional class. Notably, IP, RAP, and CRP were mutually interrelated (IP vs. RAP, r = 0.55; p < 0.0001; IP vs. CRP, r = 0.78; p < 0.0001; and RAP vs. CRP, r = 0.78; p < 0.0001). This study showed that patients with CHF may have intestinal overgrowth of pathogenic bacteria and Candida species and increased IP associated with clinical disease severity, venous blood congestion, and inflammation. Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Effects of Vernonia cinerea less methanol extract on growth and morphogenesis of Candida albicans.

PubMed

Latha, L Yoga; Darah, I; Jain, K; Sasidharan, S

2011-05-01

Vernonia (V.) cinerea Less (Asteraceae) have many therapeutic uses in the practice of traditional medicine. The methanol extract of V cinerea, was screened for antiyeast activity against pathogenic yeast Candida albicans. The antimicrobial activities were studied by using disc diffusion method and broth dilution method. The effect of the extract on the growth profile of the yeast was also examined via time-kill assay. In addition to the fungicidal effects study, microscopic observations using Scanning (SEM) electron microscopy, Transmission (TEM) electron microscopy and light microscopy (LM) were done to determine the major alterations in the microstructure of Candida (C) albicans. The extract showed a favorable antimicrobial activity against C. albicans with a minimum inhibitory concentration (MIC) value of 1.56 mg/mL. Time-kill assay suggested that Vernonia cinerea extract had completely inhibited Candida albicans growth and also exhibited prolonged antiyeast activity. The main abnormalities notes from these microscopic observations were the alterations in morphology and complete collapse of the yeast cells after 36 h of exposure to the extract. The extract of Vernonia cinerea may be an effective agent to treat the Candida albicans infection.

Proteomics of drug resistance in Candida glabrata biofilms.

PubMed

Seneviratne, C Jayampath; Wang, Yu; Jin, Lijian; Abiko, Y; Samaranayake, Lakshman P

2010-04-01

Candida glabrata is a fungal pathogen that causes a variety of mucosal and systemic infections among compromised patient populations with higher mortality rates. Previous studies have shown that biofilm mode of the growth of the fungus is highly resistant to antifungal agents compared with the free-floating or planktonic mode of growth. Therefore, in the present study, we used 2-D DIGE to evaluate the differential proteomic profiles of C. glabrata under planktonic and biofilm modes of growth. Candida glabrata biofilms were developed on polystyrene surfaces and age-matched planktonic cultures were obtained in parallel. Initially, biofilm architecture, viability, and antifungal susceptibility were evaluated. Differentially expressed proteins more than 1.5-fold in DIGE analysis were subjected to MS/MS. The transcriptomic regulation of these biomarkers was evaluated by quantitative real-time PCR. Candida glabrata biofilms were highly resistant to the antifungals and biocides compared with the planktonic mode of growth. Candida glabrata biofilm proteome when compared with its planktonic proteome showed upregulation of stress response proteins, while glycolysis enzymes were downregulated. Similar trend could be observed at transcriptomic level. In conclusion, C. glabrata biofilms possess higher amount of stress response proteins, which may potentially contribute to the higher antifungal resistance seen in C. glabrata biofilms.

Global Analysis of the Evolution and Mechanism of Echinocandin Resistance in Candida glabrata

PubMed Central

Singh-Babak, Sheena D.; Babak, Tomas; Diezmann, Stephanie; Hill, Jessica A.; Xie, Jinglin Lucy; Chen, Ying-Lien; Poutanen, Susan M.; Rennie, Robert P.; Heitman, Joseph; Cowen, Leah E.

2012-01-01

The evolution of drug resistance has a profound impact on human health. Candida glabrata is a leading human fungal pathogen that can rapidly evolve resistance to echinocandins, which target cell wall biosynthesis and are front-line therapeutics for Candida infections. Here, we provide the first global analysis of mutations accompanying the evolution of fungal drug resistance in a human host utilizing a series of C. glabrata isolates that evolved echinocandin resistance in a patient treated with the echinocandin caspofungin for recurring bloodstream candidemia. Whole genome sequencing identified a mutation in the drug target, FKS2, accompanying a major resistance increase, and 8 additional non-synonymous mutations. The FKS2-T1987C mutation was sufficient for echinocandin resistance, and associated with a fitness cost that was mitigated with further evolution, observed in vitro and in a murine model of systemic candidemia. A CDC6-A511G(K171E) mutation acquired before FKS2-T1987C(S663P), conferred a small resistance increase. Elevated dosage of CDC55, which acquired a C463T(P155S) mutation after FKS2-T1987C(S663P), ameliorated fitness. To discover strategies to abrogate echinocandin resistance, we focused on the molecular chaperone Hsp90 and downstream effector calcineurin. Genetic or pharmacological compromise of Hsp90 or calcineurin function reduced basal tolerance and resistance. Hsp90 and calcineurin were required for caspofungin-dependent FKS2 induction, providing a mechanism governing echinocandin resistance. A mitochondrial respiration-defective petite mutant in the series revealed that the petite phenotype does not confer echinocandin resistance, but renders strains refractory to synergy between echinocandins and Hsp90 or calcineurin inhibitors. The kidneys of mice infected with the petite mutant were sterile, while those infected with the HSP90-repressible strain had reduced fungal burden. We provide the first global view of mutations accompanying the evolution of fungal drug resistance in a human host, implicate the premier compensatory mutation mitigating the cost of echinocandin resistance, and suggest a new mechanism of echinocandin resistance with broad therapeutic potential. PMID:22615574

Candida profiles and antifungal resistance evolution over a decade in Lebanon.

PubMed

Araj, George Farah; Asmar, Rima George; Avedissian, Aline Zakaria

2015-09-27

Infection with and antifungal resistance of Candida species have been on the rise globally. Relevant data on these pathogens are relatively few in our region, including Lebanon, thus warranting this study. This retrospective study of Candida spp. profiles and their in vitro antifungal susceptibility was based on analysis requests for 186 Candida non-albicans and 61 C. albicans during three periods (2005-2007, 2009-2011, and 2012-2014) over the span of the last 10 years at the American University of Beirut Medical Center (AUBMC), a major tertiary care center in Lebanon. Identification of Candida was done using the API 20C AUX system, and the E-test was used to determine the minimum inhibitory concentrations (MICs) of antifungal agents. Among the 1,300-1,500 Candida isolates recovered yearly, C. albicans rates decreased from 86% in 2005 to around 60% in 2014. Simultaneously, the non-albicans rates increased from 14% in 2005 to around 40% in 2014, revealing 11 species, the most frequent of which were C. tropicalis, C. glabrata, and C. parapsilosis. All these demonstrated high resistance (35%-79%) against itraconazole, but remained uniformly susceptible (100%) to amphotericin B. Though C. albicans and the other species maintained high susceptibility against fluconazole and voriconazole, their MIC90 showed an elevated trend over time, and C. glabrata had the highest resistance rates. The observed rise in resistance among Candida spp. in Lebanon mandates the need for close surveillance and monitoring of antifungal drug resistance for both epidemiologic and treatment purposes.

Influence of Culture Media on Biofilm Formation by Candida Species and Response of Sessile Cells to Antifungals and Oxidative Stress

PubMed Central

Serrano-Fujarte, Isela; Reyna-López, Georgina Elena; Martínez-Gámez, Ma. Alejandrina; Vega-González, Arturo; Cuéllar-Cruz, Mayra

2015-01-01

The aims of the study were to evaluate the influence of culture media on biofilm formation by C. albicans, C. glabrata, C. krusei, and C. parapsilosis and to investigate the responses of sessile cells to antifungals and reactive oxygen species (ROS) as compared to planktonic cells. For biofilm formation, the Candida species were grown at different periods of time in YP or YNB media supplemented or not with 0.2 or 2% glucose. Sessile and planktonic cells were exposed to increasing concentrations of antifungals, H2O2, menadione or silver nanoparticles (AgNPs). Biofilms were observed by scanning electron microscopy (SEM) and quantified by the XTT assay. C. albicans formed biofilms preferentially in YPD containing 2% glucose (YPD/2%), C. glabrata in glucose-free YNB or supplemented with 0.2% glucose (YNB/0.2%), while C. krusei and C. parapsilosis preferred YP, YPD/0.2%, and YPD/2%. Interestingly, only C. albicans produced an exopolymeric matrix. This is the first report dealing with the in vitro effect of the culture medium and glucose on the formation of biofilms in four Candida species as well as the resistance of sessile cells to antifungals, AgNPs, and ROS. Our results suggest that candidiasis in vivo is a multifactorial and complex process where the nutritional conditions, the human immune system, and the adaptability of the pathogen should be considered altogether to provide an effective treatment of the patient. PMID:25705688

Synergy of the antibiotic colistin with echinocandin antifungals in Candida species.

PubMed

Zeidler, Ute; Bougnoux, Marie-Elisabeth; Lupan, Alexandru; Helynck, Olivier; Doyen, Antonia; Garcia, Zacarias; Sertour, Natacha; Clavaud, Cécile; Munier-Lehmann, Hélène; Saveanu, Cosmin; d'Enfert, Christophe

2013-06-01

Candida albicans is the most prevalent fungal pathogen of humans, causing a wide range of infections from harmless superficial to severe systemic infections. Improvement of the antifungal arsenal is needed since existing antifungals can be associated with limited efficacy, toxicity and antifungal resistance. Here we aimed to identify compounds that act synergistically with echinocandin antifungals and that could contribute to a faster reduction of the fungal burden. A total of 38 758 compounds were tested for their ability to act synergistically with aminocandin, a β-1,3-glucan synthase inhibitor of the echinocandin family of antifungals. The synergy between echinocandins and an identified hit was studied with chemogenomic screens and testing of individual Saccharomyces cerevisiae and C. albicans mutant strains. We found that colistin, an antibiotic that targets membranes in Gram-negative bacteria, is synergistic with drugs of the echinocandin family against all Candida species tested. The combination of colistin and aminocandin led to faster and increased permeabilization of C. albicans cells than either colistin or aminocandin alone. Echinocandin susceptibility was a prerequisite to be able to observe the synergy. A large-scale screen for genes involved in natural resistance of yeast cells to low doses of the drugs, alone or in combination, identified efficient sphingolipid and chitin biosynthesis as necessary to protect S. cerevisiae and C. albicans cells against the antifungal combination. These results suggest that echinocandin-mediated weakening of the cell wall facilitates colistin targeting of fungal membranes, which in turn reinforces the antifungal activity of echinocandins.

Immune-Response Patterns and Next Generation Sequencing Diagnostics for the Detection of Mycoses in Patients with Septic Shock-Results of a Combined Clinical and Experimental Investigation.

PubMed

Decker, Sebastian O; Sigl, Annette; Grumaz, Christian; Stevens, Philip; Vainshtein, Yevhen; Zimmermann, Stefan; Weigand, Markus A; Hofer, Stefan; Sohn, Kai; Brenner, Thorsten

2017-08-18

Fungi are of increasing importance in sepsis. However, culture-based diagnostic procedures are associated with relevant weaknesses. Therefore, culture- and next-generation sequencing (NGS)-based fungal findings as well as corresponding plasma levels of β-d-glucan, interferon gamma (INF-γ), tumor necrosis factor alpha (TNF-α), interleukin (IL)-2, -4, -6, -10, -17A, and mid-regional proadrenomedullin (MR-proADM) were evaluated in 50 septic patients at six consecutive time points within 28 days after sepsis onset. Furthermore, immune-response patterns during infections with Candida spp. were studied in a reconstituted human epithelium model. In total, 22% ( n = 11) of patients suffered from a fungal infection. An NGS-based diagnostic approach appeared to be suitable for the identification of fungal pathogens in patients suffering from fungemia as well as in patients with negative blood cultures. Moreover, MR-proADM and IL-17A in plasma proved suitable for the identification of patients with a fungal infection. Using RNA-seq., adrenomedullin (ADM) was shown to be a target gene which is upregulated early after an epithelial infection with Candida spp. In summary, an NGS-based diagnostic approach was able to close the diagnostic gap of routinely used culture-based diagnostic procedures, which can be further facilitated by plasmatic measurements of MR-proADM and IL-17A. In addition, ADM was identified as an early target gene in response to epithelial infections with Candida spp.

Reporting an outbreak of Candida pelliculosa fungemia in a neonatal intensive care unit.

PubMed

Lin, Hsiao-Chuan; Lin, Hsiang-Yu; Su, Bai-Hong; Ho, Mao-Wang; Ho, Cheng-Mao; Lee, Ching-Yi; Lin, Ming-Hsia; Hsieh, Hsin-Yang; Lin, Hung-Chih; Li, Tsai-Chung; Hwang, Kao-Pin; Lu, Jang-Jih

2013-12-01

Fungemia in preterm infants is associated with high mortality and morbidity. This study reports an outbreak of unusual fungemia in a tertiary neonatal intensive care unit (NICU). Ten Candida pelliculosa bloodstream isolates were identified from six infants hospitalized in the NICU from February to March 2009. Environmental study was performed, and genetic relatedness among the 10 clinical isolates of C pelliculosa and six control C pelliculosa strains was characterized by randomly amplified polymorphic DNA assay. In vitro susceptibility of isolates to six antifungal agents was analyzed by broth microdilution method. Amphotericin B was given to infected infants and prophylactic fluconazole was prescribed to the other noninfected extremely low birth weight infants during the outbreak. Thrombocytopenia (platelet counts <100×10(9)/L) was the early laboratory finding in four infants. One of six patients died, making overall mortality 17%. Fluconazole, voriconazole, amphotericin B, and micafungin provided good antifungal activity. Cultures from the environment and hands of caregivers were all negative. Molecular studies indicated the outbreak as caused by a single strain. The outbreak was controlled by strict hand washing, cohort infected patients, confined physicians and nurses to take care of patients, prophylactic fluconazole to uninfected neonates, and proper management of human milk. The study demonstrated the clinical importance of emerged non-albicans Candida species in NICU. For unusual pathogen isolated from immunocompromised hosts, more attention should be paid to monitor the possibility of an outbreak. Copyright © 2012. Published by Elsevier B.V.

Influence of culture media on biofilm formation by Candida species and response of sessile cells to antifungals and oxidative stress.

PubMed

Serrano-Fujarte, Isela; López-Romero, Everardo; Reyna-López, Georgina Elena; Martínez-Gámez, Ma Alejandrina; Vega-González, Arturo; Cuéllar-Cruz, Mayra

2015-01-01

The aims of the study were to evaluate the influence of culture media on biofilm formation by C. albicans, C. glabrata, C. krusei, and C. parapsilosis and to investigate the responses of sessile cells to antifungals and reactive oxygen species (ROS) as compared to planktonic cells. For biofilm formation, the Candida species were grown at different periods of time in YP or YNB media supplemented or not with 0.2 or 2% glucose. Sessile and planktonic cells were exposed to increasing concentrations of antifungals, H2O2, menadione or silver nanoparticles (AgNPs). Biofilms were observed by scanning electron microscopy (SEM) and quantified by the XTT assay. C. albicans formed biofilms preferentially in YPD containing 2% glucose (YPD/2%), C. glabrata in glucose-free YNB or supplemented with 0.2% glucose (YNB/0.2%), while C. krusei and C. parapsilosis preferred YP, YPD/0.2%, and YPD/2%. Interestingly, only C. albicans produced an exopolymeric matrix. This is the first report dealing with the in vitro effect of the culture medium and glucose on the formation of biofilms in four Candida species as well as the resistance of sessile cells to antifungals, AgNPs, and ROS. Our results suggest that candidiasis in vivo is a multifactorial and complex process where the nutritional conditions, the human immune system, and the adaptability of the pathogen should be considered altogether to provide an effective treatment of the patient.

Fungistatic activity of some perfumes against otomycotic pathogens.

PubMed

Jain, S K; Agrawal, S C

2002-04-01

The sporostatic effect of five otomycotic pathogens, i.e. Aspergillus niger, A. flavus, Absidia corymbifera, Penicillium nigricans and Candida albicans to nine different perfumes was determined on the basis of their spore germination. These organisms were isolated from patients suffering from fungal infection of the external auditory canal. Volatile vapours emanating from musk, phulwari, jasmine, nagchampa and bela caused approximately 100% inhibition in spore germination of all the test fungi. Volatiles emanating from chandan, khas and hina showed no inhibition for the test pathogens, displaying their resistant character to these perfumes.

[Aorto-bifermoral grafs infection due to Candida parapsilosis. An unusual pathogen].

PubMed

Guevara-Noriega, Kerbi Alejandro; Velescu, Alina; Zaffalon-Espinal, Diana Teresa; Mateos-Torres, Eduardo; Roig-Santamaría, Luis; Clará-Velasco, Albert

Aorto-enteric fistula is a rare and potentially lethal entity. Its presentation may be as an enteric-paraprosthetic fistula, due to injury in the gut caused by direct contact with the vascular prosthesis. We report a case of enteric-paraprosthetic fistulae with the unusual finding of Candida parapsilosis as the only isolated pathogen. A 65-year-old male, smoker, with aortobifemoral revascularisation with dacron due to aortoiliac occlusive disease, and re-intervention for thrombosis of left arm at 6 months. Hospitalisation at 22 months was required due to a toxic syndrome, which was diagnosed as enteric-paraprosthetic fistulae after complementary studies. The graft was removed and an extra-anatomic revascularisation was performed. Microbiology specimens taken from the duodenal segment in contact with the prosthesis showed the prosthetic segment and peri-prosthetic fluid were positive to C. parapsilosis. The finding of C. parapsilosis in all cultures taken during surgery, along with negative blood cultures and no other known sources of infection, is of interest. It is an unusual pathogen with low virulence and limited as regards other Candida species. Our patient had no clinical data common to cases of infection with C. parapsilosis, and the mechanism of graft infection is unknown. Graft infection by C. parapsilosis may be anecdotal. However, its consequences can also be severe. Microbiological tests can be useful to adjust antimicrobial therapy in the post-operative period, but their usefulness for determining the aetiology is doubtful, as it may be just an incidental finding. Copyright © 2016 Academia Mexicana de Cirugía A.C. Publicado por Masson Doyma México S.A. All rights reserved.

Lower genital tract infections in infertile Nigerian women compared with controls.

PubMed

Okonofua, F E; Ako-Nai, K A; Dighitoghi, M D

1995-06-01

To investigate the possibility that infertile Nigerian women have a higher rate of cervical colonisation with pathogenic and facultative organisms than fertile controls. The prevalence of common microorganisms in the vagina and endocervical canals of infertile women was compared with that of pregnant controls. The Obafemi Awolowo University Hospital Maternity Centre. 92 infertile women were compared with 86 pregnant controls. rates of isolation of Neisseria gonorrhoeae, Candida albicans, Trichomonas vaginalis and other facultative organisms in cases and controls. The rate of isolation of Neisseria gonorrheae was 17.4% among infertile women compared with 10.5% in the group of pregnant women (p > 0.05). There was no significant difference between the groups in the rate of isolation of Candida albicans, Trichomonas vaginalis and other facultative organisms. High rates of isolation of microorganisms were observed in both groups. However, women with secondary infertility had higher rate of carriage of Neisseria gonorrheae, Candida albicans and Staphylococcus aureus as compared with women with primary infertility. Nearly 15% of infertile women had previous episodes of pelvic inflammatory disease and 26% had had induced abortions. A positive history of vaginal discharge was a poor predictor of vagina and endocervical carriage of microorganisms. High rates of pathogenic organisms exist in the lower genital tract of infertile women and controls. Women with secondary infertility are more likely to have pathogenic organisms than women with primary infertility. A policy of routinely screening women for lower genital tract infections should be pursued in this population because of the high rate of infection.

Indolo[3,2-a]carbazoles from a deep-water sponge of the genus Asteropus.

PubMed

Russell, Floyd; Harmody, Dedra; McCarthy, Peter J; Pomponi, Shirley A; Wright, Amy E

2013-10-25

Two new indolo[3,2-a]carbazoles (1, 2) were isolated from a deep-water collection of a sponge of the genus Asteropus. The structures of 1 and 2 were determined through the analysis of spectroscopic data including mass spectrometry and 2D-NMR. Compound 1 showed minimum inhibitory concentrations of 25 μg/mL against the fungal pathogen Candida albicans and 50 μg/mL against methicillin-resistant Staphylococcus aureus (MRSA). Compounds 1 and 2 showed no cytotoxicity against the PANC1 human pancreatic carcinoma and NCI/ADR-RES ovarian adenocarcinoma cell lines at our standard test concentration of 5 μg/mL.

Indolo[3,2-a]carbazoles from a Deep-Water Sponge of the Genus Asteropus

PubMed Central

2013-01-01

Two new indolo[3,2-a]carbazoles (1, 2) were isolated from a deep-water collection of a sponge of the genus Asteropus. The structures of 1 and 2 were determined through the analysis of spectroscopic data including mass spectrometry and 2D-NMR. Compound 1 showed minimum inhibitory concentrations of 25 μg/mL against the fungal pathogen Candida albicans and 50 μg/mL against methicillin-resistant Staphylococcus aureus (MRSA). Compounds 1 and 2 showed no cytotoxicity against the PANC1 human pancreatic carcinoma and NCI/ADR-RES ovarian adenocarcinoma cell lines at our standard test concentration of 5 μg/mL. PMID:24063539

Invasive candidiasis: future directions in non-culture based diagnosis.

PubMed

Posch, Wilfried; Heimdörfer, David; Wilflingseder, Doris; Lass-Flörl, Cornelia

2017-09-01

Delayed initial antifungal therapy is associated with high mortality rates caused by invasive candida infections, since accurate detection of the opportunistic pathogenic yeast and its identification display a diagnostic challenge. diagnosis of candida infections relies on time-consuming methods such as blood cultures, serologic and histopathologic examination. to allow for fast detection and characterization of invasive candidiasis, there is a need to improve diagnostic tools. trends in diagnostics switch to non-culture-based methods, which allow specified diagnosis within significantly shorter periods of time in order to provide early and appropriate antifungal treatment. Areas covered: within this review comprise novel pathogen- and host-related testing methods, e.g. multiplex-PCR analyses, T2 magnetic resonance, fungus-specific DNA microarrays, microRNA characterization or analyses of IL-17 as biomarker for early detection of invasive candidiasis. Expert commentary: Early recognition and diagnosis of fungal infections is a key issue for improved patient management. As shown in this review, a broad range of novel molecular based tests for the detection and identification of Candida species is available. However, several assays are in-house assays and lack standardization, clinical validation as well as data on sensitivity and specificity. This underscores the need for the development of faster and more accurate diagnostic tests.

Microbiological Assessment of Moringa Oleifera Extracts and Its Incorporation in Novel Dental Remedies against Some Oral Pathogens

PubMed Central

Elgamily, Hanaa; Moussa, Amani; Elboraey, Asmaa; EL-Sayed, Hoda; Al-Moghazy, Marwa; Abdalla, Aboelfetoh

2016-01-01

AIM: To assess the antibacterial and antifungal potentials of different parts of Moringa oleifera plant using different extraction methods in attempts to formulate natural dental remedies from this plant. MATERIAL AND METHODS: Three solvents extracts (Ethanol, acetone, and ethyl acetate) of different parts of Egyptian Moringa tree were prepared and tested against oral pathogens: Staphylococcus aureus, Streptococcus mutans, and Candida albicans using disc diffusion method; As well as to incorporate the plant extract to formulate experimental toothpaste and mouthwash. The two dental remedies were assessed against the same microbial strains. Statistical analysis was performed using One-Way ANOVA test to compare the inhibition zone diameter and t-test. RESULTS: Ethanol extracts as well as leaves extracts demonstrated the highest significant mean inhibition zone values (P ≤ 0.05) against Staphylococcus aureus and Streptococcus mutans growth. However, all extracts revealed no inhibition zone against Candida albicans. For dental remedies, experimental toothpaste exhibited higher mean inhibition than the mouthwash against Staphylococcus aureus, Streptococcus mutans and only the toothpaste revealed antifungal effect against Candida albicans. CONCLUSION: The different extracts of different parts of Moringa showed an antibacterial effect against Staphylococcus aureus and Streptococcus mutans growth. The novel toothpaste of ethanolic leaves extract has antimicrobial and antifungal potential effects all selected strains. PMID:28028395

Mitochondrial complex I bridges a connection between regulation of carbon flexibility and gastrointestinal commensalism in the human fungal pathogen Candida albicans

PubMed Central

Yu, Xiaoyu; Li, Shanshan; Gao, Ning; Niu, Lida; Wang, Yuanyuan; Wu, Xianwei; Wu, Wenjuan; Wu, Jianhua; Zhou, Dongsheng; Zhan, Xiangjiang

2017-01-01

Efficient assimilation of alternative carbon sources in glucose-limited host niches is critical for colonization of Candida albicans, a commensal yeast that frequently causes opportunistic infection in human. C. albicans evolved mechanistically to regulate alternative carbon assimilation for the promotion of fungal growth and commensalism in mammalian hosts. However, this highly adaptive mechanism that C. albicans employs to cope with alternative carbon assimilation has yet to be clearly understood. Here we identified a novel role of C. albicans mitochondrial complex I (CI) in regulating assimilation of alternative carbon sources such as mannitol. Our data demonstrate that CI dysfunction by deleting the subunit Nuo2 decreases the level of NAD+, downregulates the NAD+-dependent mannitol dehydrogenase activity, and consequently inhibits hyphal growth and biofilm formation in conditions when the carbon source is mannitol, but not fermentative sugars like glucose. Mannitol-dependent morphogenesis is controlled by a ROS-induced signaling pathway involving Hog1 activation and Brg1 repression. In vivo studies show that nuo2Δ/Δ mutant cells are severely compromised in gastrointestinal colonization and the defect can be rescued by a glucose-rich diet. Thus, our findings unravel a mechanism by which C. albicans regulates carbon flexibility and commensalism. Alternative carbon assimilation might represent a fitness advantage for commensal fungi in successful colonization of host niches. PMID:28570675

NADPH Oxidase-Driven Phagocyte Recruitment Controls Candida albicans Filamentous Growth and Prevents Mortality

PubMed Central

Brothers, Kimberly M.; Gratacap, Remi L.; Barker, Sarah E.; Newman, Zachary R.; Norum, Ashley; Wheeler, Robert T.

2013-01-01

Candida albicans is a human commensal and clinically important fungal pathogen that grows as both yeast and hyphal forms during human, mouse and zebrafish infection. Reactive oxygen species (ROS) produced by NADPH oxidases play diverse roles in immunity, including their long-appreciated function as microbicidal oxidants. Here we demonstrate a non-traditional mechanistic role of NADPH oxidase in promoting phagocyte chemotaxis and intracellular containment of fungi to limit filamentous growth. We exploit the transparent zebrafish model to show that failed NADPH oxidase-dependent phagocyte recruitment to C. albicans in the first four hours post-infection permits fungi to germinate extracellularly and kill the host. We combine chemical and genetic tools with high-resolution time-lapse microscopy to implicate both phagocyte oxidase and dual-specific oxidase in recruitment, suggesting that both myeloid and non-myeloid cells promote chemotaxis. We show that early non-invasive imaging provides a robust tool for prognosis, strongly connecting effective early immune response with survival. Finally, we demonstrate a new role of a key regulator of the yeast-to-hyphal switching program in phagocyte-mediated containment, suggesting that there are species-specific methods for modulation of NADPH oxidase-independent immune responses. These novel links between ROS-driven chemotaxis and fungal dimorphism expand our view of a key host defense mechanism and have important implications for pathogenesis. PMID:24098114

GSL-enriched membrane microdomains in innate immune responses.

PubMed

Nakayama, Hitoshi; Ogawa, Hideoki; Takamori, Kenji; Iwabuchi, Kazuhisa

2013-06-01

Many pathogens target glycosphingolipids (GSLs), which, together with cholesterol, GPI-anchored proteins, and various signaling molecules, cluster on host cell membranes to form GSL-enriched membrane microdomains (lipid rafts). These GSL-enriched membrane microdomains may therefore be involved in host-pathogen interactions. Innate immune responses are triggered by the association of pathogens with phagocytes, such as neutrophils, macrophages and dendritic cells. Phagocytes express a diverse array of pattern-recognition receptors (PRRs), which sense invading microorganisms and trigger pathogen-specific signaling. PRRs can recognize highly conserved pathogen-associated molecular patterns expressed on microorganisms. The GSL lactosylceramide (LacCer, CDw17), which binds to various microorganisms, including Candida albicans, is expressed predominantly on the plasma membranes of human mature neutrophils and forms membrane microdomains together with the Src family tyrosine kinase Lyn. These LacCer-enriched membrane microdomains can mediate superoxide generation, migration, and phagocytosis, indicating that LacCer functions as a PRR in innate immunity. Moreover, the interactions of GSL-enriched membrane microdomains with membrane proteins, such as growth factor receptors, are important in mediating the physiological properties of these proteins. Similarly, we recently found that interactions between LacCer-enriched membrane microdomains and CD11b/CD18 (Mac-1, CR3, or αMβ2-integrin) are significant for neutrophil phagocytosis of non-opsonized microorganisms. This review describes the functional role of LacCer-enriched membrane microdomains and their interactions with CD11b/CD18.

Prunus mume extract exhibits antimicrobial activity against pathogenic oral bacteria.

PubMed

Seneviratne, Chamida J; Wong, Ricky W K; Hägg, Urban; Chen, Yong; Herath, Thanuja D K; Samaranayake, P Lakshman; Kao, Richard

2011-07-01

Prunus mume is a common fruit in Asia, which has been used in traditional Chinese medicine. In this study, we focused on the antimicrobial properties of Prunus mume extract against oral pathogens related to dental caries and periodontal diseases. A total of 15 oral pathogens including Streptococcus mutans, S. sobrinus, S. mitis, S. sanguinis, Lactobacillus acidophilus, P. gingivalis, Aggregatibacter actinomycetemcomitans, and Candida species were included in the study. Initially, agar diffusion assay was performed to screen the antimicrobial activities of Prunus mume extract. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were then determined for sensitive species. Effect of Prunus mume extract on human oral keratinocytes (HOK) viability was also tested. In the agar diffusion assay, drug suspension of 2 g/mL was able to inhibit all the bacterial species tested, but not the fungal species. MIC and MBC range of Prunus mume extract against the oral bacteria was 0.15625-0.0003 g/mL and P. gingivalis being the most susceptible species. Prune extract did not cause any detrimental effect on HOK. Prunus mume extract may be a potential candidate for developing an oral antimicrobial agent to control or prevent dental diseases associated with oral pathogenic bacteria. © 2011 The Authors. International Journal of Paediatric Dentistry © 2011 BSPD, IAPD and Blackwell Publishing Ltd.

Chitosan Loaded into a Hydrogel Delivery System as a Strategy to Treat Vaginal Co-Infection

PubMed Central

Perinelli, Diego R.; Bonacucina, Giulia; Cespi, Marco; Mastrotto, Francesca; Baffone, Wally; Casettari, Luca

2018-01-01

Polymeric hydrogels are common dosage forms designed for the topical administration of antimicrobial drugs to treat vaginal infections. One of the major advantages of using chitosan in these formulations is related to the intrinsic and broad antimicrobial activity exerted on bacteria and fungi by this natural polymer. Most vaginal yeast infections are caused by the pathogenic fungus Candida albicans. However, despite the anti-Candida activity towards and strains susceptibility to low molecular weight chitosan being documented, no information is available regarding the antimicrobial efficacy of mixed hydrogels in which chitosan is dispersed in a polymeric matrix. Therefore, the aim of the study is to evaluate the anti-Candida activity against eight different albicans and non-albicans strains of a mixed hydroxypropyl methylcellulose (HPMC)/chitosan hydrogel. Importantly, chitosan was dispersed in HPMC matrix either assembled in nanoparticles or in a monomolecular state to eventually correlate any variation in terms of rheological and mucoadhesive properties, as well as anti-Candida activity, with the chitosan form. Hydrogels containing 1% w/w chitosan, either as free polymer chain or assembled in nanoparticles, showed an improved mucoadhesiveness and an anti-Candida effect against all tested albicans and non-albicans strains. Overall, the results demonstrate the feasibility of preparing HPMC/CS mixed hydrogels intended for the prevention and treatment of Candida infections after vaginal administration. PMID:29401648

Evaluation of Genetic Diversity of Candida spp. and Klebsiella spp. Isolated from the Denture Plaque of COPD Patients.

PubMed

Przybyłowska, D; Piskorska, K; Gołaś, M; Sikora, M; Swoboda-Kopeć, E; Kostrzewa-Janicka, J; Mierzwińska-Nastalska, E

2017-01-01

Yeast-like fungi and gram-negative bacilli are the most frequent potential pathogens of the respiratory tract isolated from the denture plaque of patients with chronic obstructive pulmonary disease (COPD). Dominant species among yeast-like fungi are Candida albicans and Candida tropicalis. Significant frequency is also exhibited by Klebsiella pneumoniae and Klebsiella oxytoca. The purpose of this study was to analyze genetic diversity of the strains of C. albicans, C. tropicalis, and Klebsiella spp. present in patients in stable phases of COPD. The analysis was conducted by the random amplified polymorphic DNA (RAPD) method on clinical strains isolated from patients with COPD and control patients in overall good health. Forty one strains of Candida albicans, 12 of Candida tropicalis, as well as 9 strains of K. pneumoniae and 7 of K. oxytoca were scrutinized. The dominant species in clinical material from COPD patients was Candida albicans with a substantial degree of variations of genetic profiles. On the basis of affinity analysis, 19 genetic types were identified within this strain. An analysis of the banding patterns among C. tropicalis strains indicated the existence of 6 genetic types. A considerable diversity of genetic profiles among Klebsiella spp. also was established. The genotype diversity of Klebsiella spp. strains may indicate the endogenic character of the majority of infections, regardless of the therapy applied for the underlying condition.

[Influence of slime production and adhesion of Candida sp. on biofilm formation].

PubMed

Ciok-Pater, Emilia; Smolak, Przemysław; Wróblewska, Joanna; Gospodarek, Eugenia

2011-01-01

The increase of fungal infections in recent years is connected with the progress in medicine. The vast usage of biomaterials is an inseparable element of contemporary medicine but it also leads to development of infections. Yeast-like fungi Candida albicans are still the main pathogen of candidiasis. The ability to slime production and adhesion to polystyrene of Candida sp. on different surfaces can cause to form biofilm on surfaces of biomaterials used in production of catheters, drains and prosthesis. The aim of the study was to evaluate the influence of slime production and adhesion to polystyrene, of Candida sp. on biofilm formation on different biomaterials. 50 strains of Candida sp. were examined. They isolated from ill to Clinics of Anesthesiology and Intensive Therapy University Hospital No 1 of dr. A. Jurasza in Bydgoszcz. The ability to slime production was evaluated by Christensen method in modification Davenport and Branchini methods. The adhesion to polystyrene was evaluated by Richards et el method. The ability to produce biofilm biomaterials by the studied fungi was measured after 72 hours of incubation at 37 degrees C on different biomaterials. Yeast-like fungi Candida sp. fabricating slime and adhesion forming frequently biofilm on surface researched of biomaterials. Influence of chosen biological specificity ascertain on the ability to produce biofilm on surfaces of siliconized latex and polyvinylchloride.

[Phenotypic and genotypic identification of Candida strains isolated as nosocomial pathogens].

PubMed

Sahiner, Fatih; Ergünay, Koray; Ozyurt, Mustafa; Ardıç, Nurittin; Hoşbul, Tuğrul; Haznedaroğlu, Tunçer

2011-07-01

Over the last decade, there have been important changes in the epidemiology of Candida infections and antifungal agents used to treat these infections. In recent years, Candida species have emerged as important causes of invasive infections among patients in intensive care units. One of the main goals of this study was to evaluate the molecular epidemiology of infectious Candida species isolated in our hospital and accordingly supply data for hospital infection (HI) control. The other aim of this study was to evaluate effectiveness and practical applicability of traditional and molecular methods used to identify Candida isolates to the species level. A total of 77 Candida strains that were isolated from various clinical specimens of 60 hospitalized patients (29 male, 24 female; 7 were children) were included in the study. Fifty-seven (74%) of those isolates were defined as HI agents according to Centers for Disease Control and Prevention (CDC) criteria. The most common Candida species identified as agents of HI were C.albicans (22; 38.6%), followed by C.tropicalis (14; 24.6%), C.parapsilosis (13; 22.8%), C.glabrata (7; 12.3%) and Candida spp. (1; 1.75%). It was determined that bloodstream (26; 45.6%) and urinary tract infections (24; 42.1%) were the most frequently encountered nosocomial infections caused by Candida species. In addition it was detected that the most frequent causative agent of bloodstream infections was C.parapsilosis (10; 38.5%) and of urinary tract infections was C.albicans (12; 50%). The evaluation of advantages and disadvantages of traditional phenotypic methods [germ tube formation, chlamydospore formation in corn meal agar, growth at 45°C, colony characteristics on CHROMagar Candida medium, carbohydrate assimilation properties detected by API ID 32C (BioMerieux, France) system] and some molecular techniques [polymerase chain reaction (PCR) by using ITS-1, ITS-3 and ITS 4 primers, PCR-Restriction fragment length polymorphism (RFLP), PCRRFLP in which ITS1-ITS4 products cut by Msp I ve Bln I restriction enzymes] for the identification of Candida species revealed that CHROMagar Candida medium combined with API ID 32C kit yielded the same results (100% compatible) as molecular techniques for the species identification of Candida isolates. Since these phenotypic methods were simple and cost effective when compared to molecular techniques, they should be considered in the identification of Candida species.

Inhibition by sulfonamides of the candidacidal activity of human neutrophils.

PubMed

Lehrer, R I

1971-12-01

Sulfonamides reduced substantially the ability of normal human neutrophils to kill strains of Candida albicans and Candida tropicalis, and impaired to a lesser extent their activity against Staphylococcus aureus 502A and Serratia marcescens. Sulfonamides also inhibited (a) iodination of Candida cells by normal neutrophils; (b) candidacidal activity in cell-free systems containing purified human myeloperoxidase, hydrogen peroxide, and potassium iodide; and (c) accumulation of molecular iodine in analogously constructed cell-free systems. In contrast to these effects on reactions catalyzed by myeloperoxidase, sulfonamides exerted relatively little effect on the levels of microbicidal activity manifested by human neutrophils that lacked myeloperoxidase. Sulfonamides appear to influence the function of human neutrophils predominantly by interfering with myeloperoxidase-mediated pathways. Certain basic and clinical implications of these data are discussed.

Antifungal-protein production in maize (Zea mays) suspension cultures.

PubMed

Perri, Fabio; Della Penna, Serena; Rufini, Francesca; Patamia, Maria; Bonito, Mariantonietta; Angiolella, Letizia; Vitali, Alberto

2009-04-01

The growing emergency due to the phenomenon of drug resistance to micro-organisms has pushed forward the search for new potential drug alternatives to those already in use. Plants represent a suitable source of new antifungal molecules, as they produce a series of defensive proteins. Among them are the PRPs (pathogenesis-related proteins), shown to be effective in vitro against human pathogens. An optimized and established cell-suspension culture of maize (Zea mays) was shown to constitutively secrete in the medium a series of PRPs comprising the antifungal protein zeamatin (P33679) with a final yield of approx. 3 mg/litre. The in-vitro-produced zeamatin possessed antifungal activity towards a clinical strain of the human pathogenic yeast Candida albicans, an activity comparable with the one reported for the same protein extracted from maize seeds. Along with zeamatin, other PRPs were expressed: a 9 kDa lipid-transfer protein, a 26 kDa xylanase inhibitor and a new antifungal protein, PR-5. A fast, two-step chromatographic procedure was set up allowing the complete purification of the proteins considered, making this cell line a valuable system for the production of potential antifungal agents in a reliable and easy way.

Thionin-like peptides from Capsicum annuum fruits with high activity against human pathogenic bacteria and yeasts.

PubMed

Taveira, Gabriel B; Mathias, Luciana S; da Motta, Olney V; Machado, Olga L T; Rodrigues, Rosana; Carvalho, André O; Teixeira-Ferreira, André; Perales, Jonas; Vasconcelos, Ilka M; Gomes, Valdirene M

2014-01-01

Plants defend themselves against pathogens with production of antimicrobial peptides (AMPs). Herein we describe the discovery of a new antifungal and antibacterial peptide from fruits of Capsicum annuum that showed similarity to an already well characterized family of plant AMPs, thionins. Other fraction composed of two peptides, in which the major peptide also showed similarity to thionins. Among the obtained fractions, fraction 1, which is composed of a single peptide of 7 kDa, was sequenced by Edman method and its comparative sequence analysis in database (nr) showed similarity to thionin-like peptides. Tests against microorganisms, fraction 1 presented inhibitory activity to the cells of yeast Saccharomyces cerevisiae, Candida albicans, and Candida tropicalis and caused growth reduction to the bacteria species Escherichia coli and Pseudomonas aeruginosa. Fraction 3 caused inhibitory activity only for C. albicans and C. tropicalis. This fraction was composed of two peptides of ∼7 and 10 kDa, and the main protein band correspondent to the 7 kDa peptide, also showed similarity to thionins. This plasma membrane permeabilization assay demonstrates that the peptides present in the fractions 1 and 3 induced changes in the membranes of all yeast strains, leading to their permeabilization. Fraction 1 was capable of inhibiting acidification of the medium of glucose-induced S. cerevisiae cells 78% after an incubation time of 30 min, and opposite result was obtained for C. albicans. Experiments demonstrate that the fraction 1 and 3 were toxic and induced changes in the membranes of all yeast strains, leading to their permeabilization. Copyright © 2013 Wiley Periodicals, Inc.

Genetic and phenotypic intra-species variation in Candida albicans.

PubMed

Hirakawa, Matthew P; Martinez, Diego A; Sakthikumar, Sharadha; Anderson, Matthew Z; Berlin, Aaron; Gujja, Sharvari; Zeng, Qiandong; Zisson, Ethan; Wang, Joshua M; Greenberg, Joshua M; Berman, Judith; Bennett, Richard J; Cuomo, Christina A

2015-03-01

Candida albicans is a commensal fungus of the human gastrointestinal tract and a prevalent opportunistic pathogen. To examine diversity within this species, extensive genomic and phenotypic analyses were performed on 21 clinical C. albicans isolates. Genomic variation was evident in the form of polymorphisms, copy number variations, chromosomal inversions, subtelomeric hypervariation, loss of heterozygosity (LOH), and whole or partial chromosome aneuploidies. All 21 strains were diploid, although karyotypic changes were present in eight of the 21 isolates, with multiple strains being trisomic for Chromosome 4 or Chromosome 7. Aneuploid strains exhibited a general fitness defect relative to euploid strains when grown under replete conditions. All strains were also heterozygous, yet multiple, distinct LOH tracts were present in each isolate. Higher overall levels of genome heterozygosity correlated with faster growth rates, consistent with increased overall fitness. Genes with the highest rates of amino acid substitutions included many cell wall proteins, implicating fast evolving changes in cell adhesion and host interactions. One clinical isolate, P94015, presented several striking properties including a novel cellular phenotype, an inability to filament, drug resistance, and decreased virulence. Several of these properties were shown to be due to a homozygous nonsense mutation in the EFG1 gene. Furthermore, loss of EFG1 function resulted in increased fitness of P94015 in a commensal model of infection. Our analysis therefore reveals intra-species genetic and phenotypic differences in C. albicans and delineates a natural mutation that alters the balance between commensalism and pathogenicity. © 2015 Hirakawa et al.; Published by Cold Spring Harbor Laboratory Press.

Cell wall mannoprotein of Candida albicans induces cell cycle alternation and inhibits apoptosis of HaCaT cells via NF-κB signal pathway.

PubMed

Han, Yang; Jiang, Hang-Hang; Zhang, Yu-Jing; Hao, Xing-Jia; Sun, Yu-Zhe; Qi, Rui-Qun; Chen, Hong-Duo; Gao, Xing-Hua

2017-10-01

Candida albicans (C. albicans) is a commensal organism in human and a well-known dimorphic opportunistic pathogenic fungus. Though plenty of researches on the pathogenesis of C. albicans have been performed, the mechanism is not fully understood. The cell wall components of C. albicans have been documented to play important roles in its pathogenic processes. To further study the infectious mechanism of C. albicans, we investigated the potential functional role of its cell wall mannoprotein in cell cycle and apoptosis of HaCaT cells. We found that mannoprotein could promote the transition of cell cycle from G1/G0 to S phase, in which Cyclin D1, CDK4 and p-Rb, the major regulators of the cell cycle progression, showed significant upregulation, and CDKN1A (cyclin dependent kinase inhibitor 1A (p21)) showed significant downregulation. Mannoprotein also could inhibit apoptosis of HaCaT cells, which was well associated with increased expression of BCL2 (Bcl-2). Moreover, mannoprotein could increase the phosphorylation levels of RELA (p65) and NFKBIA (IκBα), as the key factors of NF-κB signal pathway in HaCaT cells, suggesting the activation of NF-κB signal pathway. Additionally, a NF-κB specific inhibitor, PDTC, could rescue the effect of mannoprotein on cell cycle and apoptosis of HaCaT cells, which suggested that mannoprotein could activate NF-κB signal pathway to mediate cell cycle alternation and inhibit apoptosis. Copyright © 2017. Published by Elsevier Ltd.

Targeting and synergistic action of an antifungal peptide in an antibiotic drug-delivery system.

PubMed

Park, Seong-Cheol; Kim, Young-Min; Lee, Jong-Kook; Kim, Nam-Hong; Kim, Eun-Ji; Heo, Hun; Lee, Min-Young; Lee, Jung Ro; Jang, Mi-Kyeong

2017-06-28

Amphotericin B (AmB) has been widely used against fungal infections throughout almost the entire body, including the skin, nails, oral cavity, respiratory tract, and urinary tract. However, the development of AmB-loaded nanoparticles demands a novel technique that reduces its toxicity and other associated problems. Here, we developed a pH-responsive and redox-sensitive polymer-based AmB-delivery carrier system. In particular, this system was functionalized by conjugation with the antifungal peptide histatin 5, which acts both as a targeting ligand and a synergistic antifungal molecule against Candida albicans, a major systemic fungal pathogen of humans. Our results in vitro and in vivo suggest that this drug-delivery system may serve as a novel tool to facilitate the use of antimicrobial peptides as targeting ligands to pathogenic microbes, which would open new avenues of investigation in the field of drug delivery. Copyright © 2017 Elsevier B.V. All rights reserved.

Designer cells programming quorum-sensing interference with microbes.

PubMed

Sedlmayer, Ferdinand; Hell, Dennis; Müller, Marius; Ausländer, David; Fussenegger, Martin

2018-05-08

Quorum sensing is a promising target for next-generation anti-infectives designed to address evolving bacterial drug resistance. The autoinducer-2 (AI-2) is a key quorum-sensing signal molecule which regulates bacterial group behaviors and is recognized by many Gram-negative and Gram-positive bacteria. Here we report a synthetic mammalian cell-based microbial-control device that detects microbial chemotactic formyl peptides through a formyl peptide sensor (FPS) and responds by releasing AI-2. The microbial-control device was designed by rewiring an artificial receptor-based signaling cascade to a modular biosynthetic AI-2 production platform. Mammalian cells equipped with the microbial-control gene circuit detect formyl peptides secreted from various microbes with high sensitivity and respond with robust AI-2 production, resulting in control of quorum sensing-related behavior of pathogenic Vibrio harveyi and attenuation of biofilm formation by the human pathogen Candida albicans. The ability to manipulate mixed microbial populations through fine-tuning of AI-2 levels may provide opportunities for future anti-infective strategies.

Langerhans Cells and Their Role in Oral Mucosal Diseases

PubMed Central

Upadhyay, Juhi; Upadhyay, Ram B; Agrawal, Pankaj; Jaitley, Shweta; Shekhar, Rhitu

2013-01-01

Dendritic cells are arguably the most potent antigen-presenting cells and may be the only cells capable of initiating the adaptive immune response. The epithelial residents of dendritic cells are Langerhans cells, which serve as the “sentinels” of the mucosa, altering the immune system not only to pathogen entry but also of tolerance to self antigen and commensal microbes. Oral mucosal Langerhans cells are capable of engaging and internalizing a wide variety of pathogens and have been found responsive to nickel in patients with nickel allergies, oral Candida species, oral lichen planus, lichenoid drug eruptions, graft versus host diseases, periodontal diseases median rhomboid glossitis, human immunodeficiency virus infection, hairy leukoplakia of the tongue, and oral squamous cell carcinoma. Review focuses on the role of antigen-presenting cells in particular Langerhans cells to better understand the mechanisms underlying immune responses. In this review, comprehensive detail about mucosal diseases has been compiled using the PubMed database and through textbooks. PMID:24251267

Bottom-up modeling approach for the quantitative estimation of parameters in pathogen-host interactions

PubMed Central

Lehnert, Teresa; Timme, Sandra; Pollmächer, Johannes; Hünniger, Kerstin; Kurzai, Oliver; Figge, Marc Thilo

2015-01-01

Opportunistic fungal pathogens can cause bloodstream infection and severe sepsis upon entering the blood stream of the host. The early immune response in human blood comprises the elimination of pathogens by antimicrobial peptides and innate immune cells, such as neutrophils or monocytes. Mathematical modeling is a predictive method to examine these complex processes and to quantify the dynamics of pathogen-host interactions. Since model parameters are often not directly accessible from experiment, their estimation is required by calibrating model predictions with experimental data. Depending on the complexity of the mathematical model, parameter estimation can be associated with excessively high computational costs in terms of run time and memory. We apply a strategy for reliable parameter estimation where different modeling approaches with increasing complexity are used that build on one another. This bottom-up modeling approach is applied to an experimental human whole-blood infection assay for Candida albicans. Aiming for the quantification of the relative impact of different routes of the immune response against this human-pathogenic fungus, we start from a non-spatial state-based model (SBM), because this level of model complexity allows estimating a priori unknown transition rates between various system states by the global optimization method simulated annealing. Building on the non-spatial SBM, an agent-based model (ABM) is implemented that incorporates the migration of interacting cells in three-dimensional space. The ABM takes advantage of estimated parameters from the non-spatial SBM, leading to a decreased dimensionality of the parameter space. This space can be scanned using a local optimization approach, i.e., least-squares error estimation based on an adaptive regular grid search, to predict cell migration parameters that are not accessible in experiment. In the future, spatio-temporal simulations of whole-blood samples may enable timely stratification of sepsis patients by distinguishing hyper-inflammatory from paralytic phases in immune dysregulation. PMID:26150807

Bottom-up modeling approach for the quantitative estimation of parameters in pathogen-host interactions.

PubMed

Lehnert, Teresa; Timme, Sandra; Pollmächer, Johannes; Hünniger, Kerstin; Kurzai, Oliver; Figge, Marc Thilo

2015-01-01

Opportunistic fungal pathogens can cause bloodstream infection and severe sepsis upon entering the blood stream of the host. The early immune response in human blood comprises the elimination of pathogens by antimicrobial peptides and innate immune cells, such as neutrophils or monocytes. Mathematical modeling is a predictive method to examine these complex processes and to quantify the dynamics of pathogen-host interactions. Since model parameters are often not directly accessible from experiment, their estimation is required by calibrating model predictions with experimental data. Depending on the complexity of the mathematical model, parameter estimation can be associated with excessively high computational costs in terms of run time and memory. We apply a strategy for reliable parameter estimation where different modeling approaches with increasing complexity are used that build on one another. This bottom-up modeling approach is applied to an experimental human whole-blood infection assay for Candida albicans. Aiming for the quantification of the relative impact of different routes of the immune response against this human-pathogenic fungus, we start from a non-spatial state-based model (SBM), because this level of model complexity allows estimating a priori unknown transition rates between various system states by the global optimization method simulated annealing. Building on the non-spatial SBM, an agent-based model (ABM) is implemented that incorporates the migration of interacting cells in three-dimensional space. The ABM takes advantage of estimated parameters from the non-spatial SBM, leading to a decreased dimensionality of the parameter space. This space can be scanned using a local optimization approach, i.e., least-squares error estimation based on an adaptive regular grid search, to predict cell migration parameters that are not accessible in experiment. In the future, spatio-temporal simulations of whole-blood samples may enable timely stratification of sepsis patients by distinguishing hyper-inflammatory from paralytic phases in immune dysregulation.

Immune recovery in HIV-infected patients after Candida esophagitis is impaired despite long-term antiretroviral therapy

PubMed Central

Stuehler, Claudia; Bernardini, Claudia; Elzi, Luigia; Stoeckle, Marcel; Zimmerli, Stefan; Furrer, Hansjakob; Günthard, Huldrych F.; Leibundgut-Landmann, Salomé; Battegay, Manuel; Khanna, Nina

2016-01-01

Objective: Candida esophagitis belongs to the most common AIDS-defining diseases; however, a comprehensive immune pathogenic concept is lacking. Design: We investigated the immune status of 37 HIV-1-infected patients from the Swiss HIV cohort study at diagnosis of Candida esophagitis, 1 year before, 1 year later and after 2 years of suppressed HIV RNA. We compared these patients with three groups: 37 HIV-1-infected patients without Candida esophagitis but similar CD4+ cell counts as the patients at diagnosis (advanced HIV group), 15 HIV-1-infected patients with CD4+ cell counts higher than 500 cells/μl, CD4+ cell nadirs higher than 350 cells/μl and suppressed HIV RNA under combination antiretroviral therapy (cART) (early cART group) and 20 healthy individuals. Methods: We investigated phenotype, cytokine production and proliferative capacity of different immune cells by flow cytometry and enzyme-linked immunosorbent spot. Results: We found that patients with Candida esophagitis had nearly abolished CD4+ cell proliferation in response to Candida albicans, significantly increased percentages of dysfunctional CD4+ cells, significantly decreased cytotoxic natural killer cell counts and peripheral innate lymphoid cell counts and significantly reduced IFN-γ and IL-17 production compared with the early cART group and healthy individuals. Most of these defects remained for more than 2 years despite viral suppression. The advanced HIV group without opportunistic infection showed partly improved immune recovery. Conclusion: Our data indicate that Candida esophagitis in HIV-1-infected patients is caused by an accumulation of multiple, partly Candida-specific immunological defects. Long-term immune recovery is impaired, illustrating that specific immunological gaps persist despite cART. These data also support the rationale for early cART initiation to prevent irreversible immune defects. PMID:27149086

Applying Convergent Immunity to Innovative Vaccines Targeting Staphylococcus aureus

PubMed Central

Yeaman, Michael R.; Filler, Scott G.; Schmidt, Clint S.; Ibrahim, Ashraf S.; Edwards, John E.; Hennessey, John P.

2014-01-01

Recent perspectives forecast a new paradigm for future “third generation” vaccines based on commonalities found in diverse pathogens or convergent immune defenses to such pathogens. For Staphylococcus aureus, recurring infections and a limited success of vaccines containing S. aureus antigens imply that native antigens induce immune responses insufficient for optimal efficacy. These perspectives exemplify the need to apply novel vaccine strategies to high-priority pathogens. One such approach can be termed convergent immunity, where antigens from non-target organisms that contain epitope homologs found in the target organism are applied in vaccines. This approach aims to evoke atypical immune defenses via synergistic processes that (1) afford protective efficacy; (2) target an epitope from one organism that contributes to protective immunity against another; (3) cross-protect against multiple pathogens occupying a common anatomic or immunological niche; and/or (4) overcome immune subversion or avoidance strategies of target pathogens. Thus, convergent immunity has a potential to promote protective efficacy not usually elicited by native antigens from a target pathogen. Variations of this concept have been mainstays in the history of viral and bacterial vaccine development. A more far-reaching example is the pre-clinical evidence that specific fungal antigens can induce cross-kingdom protection against bacterial pathogens. This trans-kingdom protection has been demonstrated in pre-clinical studies of the recombinant Candida albicans agglutinin-like sequence 3 protein (rAls3) where it was shown that a vaccine containing rAls3 provides homologous protection against C. albicans, heterologous protection against several other Candida species, and convergent protection against several strains of S. aureus. Convergent immunity reflects an intriguing new approach to designing and developing vaccine antigens and is considered here in the context of vaccines to target S. aureus. PMID:25309545

Potential Targets for Antifungal Drug Discovery Based on Growth and Virulence in Candida albicans

PubMed Central

Li, Xiuyun; Hou, Yinglong; Yue, Longtao; Liu, Shuyuan; Du, Juan

2015-01-01

Fungal infections, especially infections caused by Candida albicans, remain a challenging problem in clinical settings. Despite the development of more-effective antifungal drugs, their application is limited for various reasons. Thus, alternative treatments with drugs aimed at novel targets in C. albicans are needed. Knowledge of growth and virulence in fungal cells is essential not only to understand their pathogenic mechanisms but also to identify potential antifungal targets. This article reviews the current knowledge of the mechanisms of growth and virulence in C. albicans and examines potential targets for the development of new antifungal drugs. PMID:26195510

A novel role of the ferric reductase Cfl1 in cell wall integrity, mitochondrial function, and invasion to host cells in Candida albicans.

PubMed

Yu, Qilin; Dong, Yijie; Xu, Ning; Qian, Kefan; Chen, Yulu; Zhang, Biao; Xing, Laijun; Li, Mingchun

2014-11-01

Candida albicans is an important opportunistic pathogen, causing both superficial mucosal infections and life-threatening systemic diseases. Iron acquisition is an important factor for pathogen-host interaction and also a significant element for the pathogenicity of this organism. Ferric reductases, which convert ferric iron into ferrous iron, are important components of the high-affinity iron uptake system. Sequence analyses have identified at least 17 putative ferric reductase genes in C. albicans genome. CFL1 was the first ferric reductase identified in C. albicans. However, little is known about its roles in C. albicans physiology and pathogenicity. In this study, we found that disruption of CFL1 led to hypersensitivity to chemical and physical cell wall stresses, activation of the cell wall integrity (CWI) pathway, abnormal cell wall composition, and enhanced secretion, indicating a defect in CWI in this mutant. Moreover, this mutant showed abnormal mitochondrial activity and morphology, suggesting a link between ferric reductases and mitochondrial function. In addition, this mutant displayed decreased ability of adhesion to both the polystyrene microplates and buccal epithelial cells and invasion of host epithelial cells. These findings revealed a novel role of C. albicans Cfl1 in maintenance of CWI, mitochondrial function, and interaction between this pathogen and the host. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Fungal Chitin Dampens Inflammation through IL-10 Induction Mediated by NOD2 and TLR9 Activation

PubMed Central

Wagener, Jeanette; Malireddi, R. K. Subbarao; Lenardon, Megan D.; Köberle, Martin; Vautier, Simon; MacCallum, Donna M.; Biedermann, Tilo; Schaller, Martin; Netea, Mihai G.; Kanneganti, Thirumala-Devi; Brown, Gordon D.; Brown, Alistair J. P.; Gow, Neil A. R.

2014-01-01

Chitin is an essential structural polysaccharide of fungal pathogens and parasites, but its role in human immune responses remains largely unknown. It is the second most abundant polysaccharide in nature after cellulose and its derivatives today are widely used for medical and industrial purposes. We analysed the immunological properties of purified chitin particles derived from the opportunistic human fungal pathogen Candida albicans, which led to the selective secretion of the anti-inflammatory cytokine IL-10. We identified NOD2, TLR9 and the mannose receptor as essential fungal chitin-recognition receptors for the induction of this response. Chitin reduced LPS-induced inflammation in vivo and may therefore contribute to the resolution of the immune response once the pathogen has been defeated. Fungal chitin also induced eosinophilia in vivo, underpinning its ability to induce asthma. Polymorphisms in the identified chitin receptors, NOD2 and TLR9, predispose individuals to inflammatory conditions and dysregulated expression of chitinases and chitinase-like binding proteins, whose activity is essential to generate IL-10-inducing fungal chitin particles in vitro, have also been linked to inflammatory conditions and asthma. Chitin recognition is therefore critical for immune homeostasis and is likely to have a significant role in infectious and allergic disease. Authors Summary Chitin is the second most abundant polysaccharide in nature after cellulose and an essential component of the cell wall of all fungal pathogens. The discovery of human chitinases and chitinase-like binding proteins indicates that fungal chitin is recognised by cells of the human immune system, shaping the immune response towards the invading pathogen. We show that three immune cell receptors– the mannose receptor, NOD2 and TLR9 recognise chitin and act together to mediate an anti-inflammatory response via secretion of the cytokine IL-10. This mechanism may prevent inflammation-based damage during fungal infection and restore immune balance after an infection has been cleared. By increasing the chitin content in the cell wall pathogenic fungi may influence the immune system in their favour, by down-regulating protective inflammatory immune responses. Furthermore, gene mutations and dysregulated enzyme activity in the described chitin recognition pathway are implicated in inflammatory conditions such as Crohn's Disease and asthma, highlighting the importance of the discovered mechanism in human health. PMID:24722226

Spaceflight Enhances Cell Aggregation and Random Budding in Candida albicans

PubMed Central

Woolley, Christine M.; Barrila, Jennifer; Buchanan, Kent; McCracken, James; Inglis, Diane O.; Searles, Stephen C.; Nelman-Gonzalez, Mayra A.; Ott, C. Mark; Wilson, James W.; Pierson, Duane L.; Stefanyshyn-Piper, Heidemarie M.; Hyman, Linda E.; Nickerson, Cheryl A.

2013-01-01

This study presents the first global transcriptional profiling and phenotypic characterization of the major human opportunistic fungal pathogen, Candida albicans, grown in spaceflight conditions. Microarray analysis revealed that C. albicans subjected to short-term spaceflight culture differentially regulated 452 genes compared to synchronous ground controls, which represented 8.3% of the analyzed ORFs. Spaceflight-cultured C. albicans–induced genes involved in cell aggregation (similar to flocculation), which was validated by microscopic and flow cytometry analysis. We also observed enhanced random budding of spaceflight-cultured cells as opposed to bipolar budding patterns for ground samples, in accordance with the gene expression data. Furthermore, genes involved in antifungal agent and stress resistance were differentially regulated in spaceflight, including induction of ABC transporters and members of the major facilitator family, downregulation of ergosterol-encoding genes, and upregulation of genes involved in oxidative stress resistance. Finally, downregulation of genes involved in actin cytoskeleton was observed. Interestingly, the transcriptional regulator Cap1 and over 30% of the Cap1 regulon was differentially expressed in spaceflight-cultured C. albicans. A potential role for Cap1 in the spaceflight response of C. albicans is suggested, as this regulator is involved in random budding, cell aggregation, and oxidative stress resistance; all related to observed spaceflight-associated changes of C. albicans. While culture of C. albicans in microgravity potentiates a global change in gene expression that could induce a virulence-related phenotype, no increased virulence in a murine intraperitoneal (i.p.) infection model was observed under the conditions of this study. Collectively, our data represent an important basis for the assessment of the risk that commensal flora could play during human spaceflight missions. Furthermore, since the low fluid-shear environment of microgravity is relevant to physical forces encountered by pathogens during the infection process, insights gained from this study could identify novel infectious disease mechanisms, with downstream benefits for the general public. PMID:24324620

Retigeric acid B enhances the efficacy of azoles combating the virulence and biofilm formation of Candida albicans.

PubMed

Chang, Wenqiang; Li, Ying; Zhang, Li; Cheng, Aixia; Liu, Yongqing; Lou, Hongxiang

2012-01-01

Candida albicans is one of the most prevalent human opportunistic pathogens. C. albicans undergoes a yeast-to-hyphal transition that has been identified as a virulence factor as well as a critical element for mature biofilm formation. A previous study in our lab showed retigeric acid B (RAB), a lichen derived pentacyclic triterpenoid, displayed synergistic antifungal activity with azoles. We now showed that this combination also proved to be adequate in combating the formation of hyphae in vitro. In vivo tests with mice demonstrated RAB could markedly enhance the efficacy of fluconazole to promote the host's longevity through inhibiting hyphae formation and adherence to host cells. It was also observed that RAB and azoles interacted synergistically to block the formation of biofilm. Our data suggested the attenuated yeast-to-hyphal switch contributed to the defect of mature biofilm formation. Moreover, quantitative real-time polymerase chain reaction (qPCR) analysis showed RAB could reduce the transcript level of MDR1, a multidrug efflux pump, and caused a slight transcriptional reduction for another drug pump related gene CDR1. Taken together, our work provides a potential application to combat candidiasis using the combination of RAB and azoles.

CdTe/CdS-MPA quantum dots as fluorescent probes to label yeast cells: synthesis, characterization and conjugation with Concanavalin A

NASA Astrophysics Data System (ADS)

Kato, Ilka T.; Santos, Camila C.; Benetti, Endi; Tenório, Denise P. L. A.; Cabral Filho, Paulo E.; Sabino, Caetano P.; Fontes, Adriana; Santos, Beate S.; Prates, Renato A.; Ribeiro, Martha S.

2012-03-01

Candida albicans is the most frequent human opportunistic pathogenic fungus and one of the most important causes of nosocomial infections. In fact, diagnosis of invasive candidiasis presents unique problems. The aim of this work was to evaluate, by fluorescence image analysis, cellular labeling of C. albicans with CdTe/CdS quantum dots conjugated or not to concanavalin A (ConA). Yeast cells were incubated with CdTe/CdS quantum dots (QD) stabilized with mercaptopropionic acid (MPA) (emission peak at 530 nm) for 1 hour. In the overall study we observed no morphological alterations. The fluorescence microscopic analysis of the yeast cells showed that the non-functionalized QDs do not label C. albicans cells, while for the QD conjugated to ConA the cells showed a fluorescence profile indicating that the membrane was preferentially marked. This profile was expected since Concanavalin A is a protein that binds specifically to terminal carbohydrate residues at the membrane cell surface. The results suggest that the QD-labeled Candida cells represent a promising tool to open new possibilities for a precise evaluation of fungal infections in pathological conditions.

Nicotine Enhances Interspecies Relationship between Streptococcus mutans and Candida albicans.

PubMed

Liu, Shiyu; Qiu, Wei; Zhang, Keke; Zhou, Xuedong; Ren, Biao; He, Jinzhi; Xu, Xin; Cheng, Lei; Li, Mingyun

2017-01-01

Streptococcus mutans and Candida albicans are common microorganisms in the human oral cavity. The synergistic relationship between these two species has been deeply explored in many studies. In the present study, the effect of alkaloid nicotine on the interspecies between S. mutans and C. albicans is explored. We developed a dual-species biofilm model and studied biofilm biomass, biofilm structure, synthesis of extracellular polysaccharides (EPS), and expression of glucosyltransferases (Gtfs). Biofilm formation and bacterial and fungal cell numbers in dual-species biofilms increased in the presence of nicotine. More C. albicans cells were present in the dual-species biofilms in the nicotine-treated groups as determined by scanning electron microscopy. The synthesis of EPS was increased by 1 mg/ml of nicotine as detected by confocal laser scanning microscopy. The result of qRT-PCR showed gtfs expression was upregulated when 1 mg/ml of nicotine was used. We speculate that nicotine promoted the growth of S. mutans , and more S. mutans cells attracted more C. albicans cells due to the interaction between two species. Since S. mutans and C. albicans are putative pathogens for dental caries, the enhancement of the synergistic relationship by nicotine may contribute to caries development in smokers.

Evaluation of Antifungal Activity and Mechanism of Action of Citral against Candida albicans.

PubMed

Leite, Maria Clerya Alvino; Bezerra, André Parente de Brito; de Sousa, Janiere Pereira; Guerra, Felipe Queiroga Sarmento; Lima, Edeltrudes de Oliveira

2014-01-01

Candida albicans is a yeast that commensally inhabits the human body and can cause opportunistic or pathogenic infections. Objective. To investigate the antifungal activity of citral against C. albicans. Methodology. The minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC) were determined by the broth microdilution techniques. We also investigated possible citral action on cell walls (0.8 M sorbitol), cell membranes (citral to ergosterol binding), the time-kill curve, and biological activity on the yeast's morphology. Results. The MIC and MFC of citral were, respectively, 64 µg/mL and 256 µg/mL. Involvement with the cell wall and ergosterol binding were excluded as possible mechanisms of action. In the morphological interference assay, it was observed that the product inhibited pseudohyphae and chlamydoconidia formation. The MIC and the MFC of citral required only 4 hours of exposure to effectively kill 99.9% of the inoculum. Conclusion. Citral showed in vitro antifungal potential against strains of C. albicans. Citral's mechanism of action does not involve the cell wall or ergosterol, and further study is needed to completely describe its effects before being used in the future as a component of new antifungals.

Recognition and Blocking of Innate Immunity Cells by Candida albicans Chitin ▿ †

PubMed Central

Mora-Montes, Héctor M.; Netea, Mihai G.; Ferwerda, Gerben; Lenardon, Megan D.; Brown, Gordon D.; Mistry, Anita R.; Kullberg, Bart Jan; O'Callaghan, Chris A.; Sheth, Chirag C.; Odds, Frank C.; Brown, Alistair J. P.; Munro, Carol A.; Gow, Neil A. R.

2011-01-01

Chitin is a skeletal cell wall polysaccharide of the inner cell wall of fungal pathogens. As yet, little about its role during fungus-host immune cell interactions is known. We show here that ultrapurified chitin from Candida albicans cell walls did not stimulate cytokine production directly but blocked the recognition of C. albicans by human peripheral blood mononuclear cells (PBMCs) and murine macrophages, leading to significant reductions in cytokine production. Chitin did not affect the induction of cytokines stimulated by bacterial cells or lipopolysaccharide (LPS), indicating that blocking was not due to steric masking of specific receptors. Toll-like receptor 2 (TLR2), TLR4, and Mincle (the macrophage-inducible C-type lectin) were not required for interactions with chitin. Dectin-1 was required for immune blocking but did not bind chitin directly. Cytokine stimulation was significantly reduced upon stimulation of PBMCs with heat-killed chitin-deficient C. albicans cells but not with live cells. Therefore, chitin is normally not exposed to cells of the innate immune system but is capable of influencing immune recognition by blocking dectin-1-mediated engagement with fungal cell walls. PMID:21357722

DNA-dependent RNA polymerase II from Candida species is a multiple zinc-containing metalloenzyme.

PubMed

Patturajan, M; Sevugan, M; Chatterji, D

1999-08-01

We have purified DNA-dependent RNA polymerase II from Candida albicans, a human pathogenic yeast. The enzyme consists of 9 polypeptides that are unique to C. albicans, their mobility on SDS-PAGE being different from the mobility of the corresponding subunits of RNA polymerase II from Saccharomyces cerevisiae or C. utilis. In the present study we also demonstrate that RNA pol II from C. albican and C. utilis are metalloproteins containing approximately 5 mol of zinc per mole of enzyme. Although prolonged dialysis in 10 or 20 mM EDTA failed to remove Zn(II) from the C. albicans enzyme, in the C. utilis enzyme 3 Zn(II) ions could be removed and then reconstituted in the presence of excess Zn(II). o-Phenanthroline (5 mM) removed Zn(II) from C. albicans enzyme irreversibly in a time-dependent fashion with concomitant loss of enzyme activity. Circular dichroism studies revealed structural changes on removal of zinc, thus suggesting a role for Zn in maintenance of structural stability. Further, we demonstrate that the largest subunit of the C. utilis enzyme and the 3 large subunits of the C. albicans enzyme can bind radioactive zinc.

Efficacy of ferulic acid encapsulated chitosan nanoparticles against Candida albicans biofilm.

PubMed

Panwar, Richa; Pemmaraju, Suma C; Sharma, Asvene K; Pruthi, Vikas

2016-06-01

Candida albicans, an opportunistic fungal pathogen is a major causative agent of superficial to systemic life-threating biofilm infections on indwelling medical devices. These biofilms acts as double edge swords owing to their resistance towards antibiotics and immunological barriers. To overcome this threat ferulic acid encapsulated chitosan nanoparticles (FA-CSNPs) were formulated to assess its efficacy as an antibiofilm agent against C. albicans. These FA-CSNPs were synthesized using ionotropic gelation method and observed through field emission scanning electron microscopy (FESEM) and fluorescent microscopy. Assessment of successful encapsulation and stability of ferulic acid into chitosan nanoparticles was made using Fourier transform infrared spectrum (FTIR), (1)H NMR and thermal analyses. Synthesized FA-CSNPs, were found to be cytocompatible, when tested using Human Embryonic Kidney (HEK-293) cell lines. XTT assay revealed that FA-CSNPs reduced the cell metabolic activity of C. albicans upto 22.5% as compared to native ferulic acid (63%) and unloaded CSNPs (88%) after 24 h incubation. Disruption of C. albicans biofilm architecture was visualized by FESEM. Results highlighted the potential of FA-CSNPs to be used as an effective alternative to the conventional antifungal therapeutics. Copyright © 2016 Elsevier Ltd. All rights reserved.

Role of protein phosphomannosylation in the Candida tropicalis-macrophage interaction.

PubMed

Hernández-Chávez, Marco J; Franco, Bernardo; Clavijo-Giraldo, Diana M; Hernández, Nahúm V; Estrada-Mata, Eine; Mora-Montes, Héctor Manuel

2018-04-27

Candida tropicalis is an opportunistic fungal pathogen responsible for mucosal and systemic infections. The cell wall is the initial contact point between a fungal cell and the host immune system, and mannoproteins are important components that play key roles when interacting with host cells. In C. albicans, mannans are modified by mannosyl-phosphate moieties, named phosphomannans, which can work as molecular scaffolds to synthesize β1,2-mannooligosaccharides, and MNN4 is a positive regulator of the phosphomannosylation pathway. Here, we showed that C. tropicalis also displays phosphomannans on the cell surface, but the amount of this cell wall component varies depending on the fungal strain. We also identified a functional ortholog of CaMNN4 in C. tropicalis. Disruption of this gene caused depletion of phosphomannan content. The C. tropicalis mnn4Δ did not show defects in the ability to stimulate cytokine production by human mononuclear cells but displayed virulence attenuation in an insect model of candidiasis. When the mnn4Δ-macrophage interaction was analyzed, results showed that presence of cell wall phosphomannan was critical for C. tropicalis phagocytosis. Finally, our results strongly suggest a differential role for phosphomannans during phagocytosis of C. albicans and C. tropicalis.

Phytochemicals as Inhibitors of Candida Biofilm.

PubMed

Raut, Jayant Shankar; Karuppayil, Sankunny Mohan

2016-01-01

Candida biofilm and associated infections is a serious threat to the large population of immunocompromised patients. Biofilm growth on prosthetic devices or host tissue shows reduced sensitivity to antifungal agents and persists as a reservoir of infective cells. Options for successful treatment of biofilm associated Candida infections are restricted because most of the available antifungal drugs fail to eradicate biofilms. Various plant actives are known to possess interesting antifungal properties. To explore and review the potential of phytochemicals as a novel strategy against Candida biofilms is the intent of present article. Thorough literature search is performed to identify Candida biofilm inhibitors of plant origin. An account of efficacy of selected phytochemicals is presented taking into consideration their biofilm inhibitory concentrations. This review discusses biofilm formation by Candida species, their involvement in human infections, and associated drug resistance. It gives insight into the biofilm inhibitory potential of various phytochemicals. Based on the available reports including the work done in our laboratory, several plant extracts, essential oils and phytomolecules have been identified as excellent inhibitors of biofilms of C. albicans and non-albicans Candida species (NACS). Selected phytochemicals which exhibit activities at low concentrations without displaying toxicity to host are potential therapeutic agents against biofilm associated Candida infections. In vivo testing in animal models and clinical trials in humans are required to be taken up seriously to propose few of the phytochemicals as candidate drug molecules.

A comparative investigation of azole susceptibility in Candida isolates from vulvovaginal candidiasis and recurrent vulvovaginal candidiasis patients in Ghana.

PubMed

Adjapong, Gloria; Hale, Marie; Garrill, Ashley

2017-08-01

Vulvovaginal candidiasis (VVC) and recurrent vulvovaginal candidiasis (RVVC) affect millions of women and are typically treated with azoles. We know little about azole susceptibility of Candida species from VVC versus RVVC patients, and nothing about African isolates. We have investigated the susceptibility of Candida isolates from Ghana to fluconazole, itraconazole and/or voriconazole. The percentage of Candida albicans isolates showing susceptibility was significantly lower in RVVC than VVC patients. Isolates of Candida parapsilosis and Candida tropicalis showed a similar trend. For Candida glabrata there was no observed difference. The data indicate a decreased susceptibility in selected Candida species from RVVC patients. © The Author 2016. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

[National Trends in the Distribution of Candida Species Causing Candidemia in Japan from 2003 to 2014].

PubMed

Kakeya, Hiroshi; Yamada, Koichi; Kaneko, Yukihiro; Yanagihara, Katsunori; Tateda, Kazuhiro; Maesaki, Shigefumi; Takesue, Yoshio; Tomono, Kazunori; Kadota, Jun-Ichi; Kaku, Mitsuo; Miyazaki, Yoshitsugu; Kamei, Katsuhiko; Shibuya, Kazutoshi; Niki, Yoshitiho; Yoshida, Minoru; Sei, Yoshihiro

2018-01-01

The Epidemiological Investigation Committee for Human Mycoses in Japan performed a retrospective epidemiological survey of candidemia and causative Candida species. Data from 2003 to 2014 were collected from 10 Japanese university hospitals. A total of 328,318 blood cultures were included. The prevalence of fungi in all cultures and in positive cultures were 0.58±0.09% and 4.46±0.66%, respectively. Among the results that were positive for Candida species (N=1,921), Candida albicans was the most common species (39.5%) and was followed by Candida parapsilosis (23.3%), Candida glabrata (13.2%), Candida tropicalis (7.1%), Candida krusei (3.2%), and others (13.7%). During the last 6 years, the frequency of C. albicans has significantly decreased in Japan, while that of C. glabrata has increased. Additional surveys are needed to continuously monitor the trends in the distribution of candidemia.

Host carbon sources modulate cell wall architecture, drug resistance and virulence in a fungal pathogen

PubMed Central

Ene, Iuliana V; Adya, Ashok K; Wehmeier, Silvia; Brand, Alexandra C; MacCallum, Donna M; Gow, Neil A R; Brown, Alistair J P

2012-01-01

The survival of all microbes depends upon their ability to respond to environmental challenges. To establish infection, pathogens such as Candida albicans must mount effective stress responses to counter host defences while adapting to dynamic changes in nutrient status within host niches. Studies of C. albicans stress adaptation have generally been performed on glucose-grown cells, leaving the effects of alternative carbon sources upon stress resistance largely unexplored. We have shown that growth on alternative carbon sources, such as lactate, strongly influence the resistance of C. albicans to antifungal drugs, osmotic and cell wall stresses. Similar trends were observed in clinical isolates and other pathogenic Candida species. The increased stress resistance of C. albicans was not dependent on key stress (Hog1) and cell integrity (Mkc1) signalling pathways. Instead, increased stress resistance was promoted by major changes in the architecture and biophysical properties of the cell wall. Glucose- and lactate-grown cells displayed significant differences in cell wall mass, ultrastructure, elasticity and adhesion. Changes in carbon source also altered the virulence of C. albicans in models of systemic candidiasis and vaginitis, confirming the importance of alternative carbon sources within host niches during C. albicans infections. PMID:22587014

Silver nanoparticles: Antimicrobial activity, cytotoxicity, and synergism with N-acetyl cysteine.

PubMed

Hamed, Selwan; Emara, Mohamed; Shawky, Riham M; El-Domany, Ramadan A; Youssef, Tareq

2017-08-01

The fast progression of nanotechnology has led to novel therapeutic interventions. Antimicrobial activities of silver nanoparticles (Ag NPs) were tested against standard ATCC strains of Staphylococcus aureus (ATCC 9144), Escherichia coli (O157:H7), Pseudomonas aeruginosa (ATCC 27853), and Candida albicans (ATCC 90028) in addition to 60 clinical isolates collected from cancer patients. Antimicrobial activity was tested by disk diffusion method and MIC values for Ag NPs alone and in combination with N-acetylcysteine (NAC) against tested pathogens were determined by broth microdilution method. Ag NPs showed a robust antimicrobial activity against all tested pathogens and NAC substantially enhanced the antimicrobial activity of Ag NPs against all tested pathogens. Synergism between Ag NPs and NAC has been confirmed by checkerboard assay. The effect of Ag NPs on tested pathogens was further scrutinized by Transmission Electron Microscope (TEM) which showed disruption of cell wall in both bacteria and fungi. Ag NPs abrogated the activity of respiratory chain dehydrogenase of all tested pathogens and released muramic acid content from S. aureus in culture. The cytotoxic effect of Ag NPs alone and in combination with NAC was examined using human HepG2 cells and this revealed no cytotoxicity at MIC values of Ag NPs and interestingly, NAC reduced the cytotoxic effect of Ag NPs at concentrations higher than their MIC values. Taken together, Ag NPs have robust antimicrobial activity and NAC substantially enhances their antimicrobial activities against MDR pathogens which would provide a novel safe, effective, and inexpensive therapeutic approach to control the prevalence of MDR pathogens. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Candida krusei and Candida glabrata reduce the filamentation of Candida albicans by downregulating expression of HWP1 gene.

PubMed

de Barros, Patrícia Pimentel; Freire, Fernanda; Rossoni, Rodnei Dennis; Junqueira, Juliana Campos; Jorge, Antonio Olavo Cardoso

2017-07-01

Pathogenicity of Candida albicans is associated with its capacity switch from yeast-like to hyphal growth. The hyphal form is capable to penetrate the epithelial surfaces and to damage the host tissues. Therefore, many investigations have focused on mechanisms that control the morphological transitions of C. albicans. Recently, certain studies have showed that non-albicans Candida species can reduce the capacity of C. albicans to form biofilms and to develop candidiasis in animal models. Then, the objective of this study was to evaluate the effects of Candida krusei and Candida glabrata on the morphogenesis of C. albicans. Firstly, the capacity of reference and clinical strains of C. albicans in forming hyphae was tested in vitro. After that, the expression of HWP1 (hyphal wall protein 1) gene was determined by quantitative real-time PCR (polymerase chain reaction) assay. For both reference and clinical strains, a significant inhibition of the hyphae formation was observed when C. albicans was incubated in the presence of C. krusei or C. glabrata compared to the control group composed only by C. albicans. In addition, the culture mixed of C. albicans-C. krusei or C. albicans-C. glabrata reduced significantly the expression of HWP1 gene of C. albicans in relation to single cultures of this specie. In both filamentation and gene expression assays, C. krusei showed the higher inhibitory activity on the morphogenesis of C. albicans compared to C. glabrata. C. krusei and C. glabrata are capable to reduce the filamentation of C. albicans and consequently decrease the expression of the HWP1 gene.

Conservation and Divergence in the Candida Species Biofilm Matrix Mannan-Glucan Complex Structure, Function, and Genetic Control.

PubMed

Dominguez, Eddie; Zarnowski, Robert; Sanchez, Hiram; Covelli, Antonio S; Westler, William M; Azadi, Parastoo; Nett, Jeniel; Mitchell, Aaron P; Andes, David R

2018-04-03

Candida biofilms resist the effects of available antifungal therapies. Prior studies with Candida albicans biofilms show that an extracellular matrix mannan-glucan complex (MGCx) contributes to antifungal sequestration, leading to drug resistance. Here we implement biochemical, pharmacological, and genetic approaches to explore a similar mechanism of resistance for the three most common clinically encountered non- albicans Candida species (NAC). Our findings reveal that each Candida species biofilm synthesizes a mannan-glucan complex and that the antifungal-protective function of this complex is conserved. Structural similarities extended primarily to the polysaccharide backbone (α-1,6-mannan and β-1,6-glucan). Surprisingly, biochemical analysis uncovered stark differences in the branching side chains of the MGCx among the species. Consistent with the structural analysis, similarities in the genetic control of MGCx production for each Candida species also appeared limited to the synthesis of the polysaccharide backbone. Each species appears to employ a unique subset of modification enzymes for MGCx synthesis, likely accounting for the observed side chain diversity. Our results argue for the conservation of matrix function among Candida spp. While biogenesis is preserved at the level of the mannan-glucan complex backbone, divergence emerges for construction of branching side chains. Thus, the MGCx backbone represents an ideal drug target for effective pan- Candida species biofilm therapy. IMPORTANCE Candida species, the most common fungal pathogens, frequently grow as a biofilm. These adherent communities tolerate extremely high concentrations of antifungal agents, due in large part, to a protective extracellular matrix. The present studies define the structural, functional, and genetic similarities and differences in the biofilm matrix from the four most common Candida species. Each species synthesizes an extracellular mannan-glucan complex (MGCx) which contributes to sequestration of antifungal drug, shielding the fungus from this external assault. Synthesis of a common polysaccharide backbone appears conserved. However, subtle structural differences in the branching side chains likely rely upon unique modification enzymes, which are species specific. Our findings identify MGCx backbone synthesis as a potential pan- Candida biofilm therapeutic target. Copyright © 2018 Dominguez et al.

Isocyanides inhibit human heme oxygenases at the verdoheme stage.

PubMed

Evans, John P; Kandel, Sylvie; Ortiz de Montellano, Paul R

2009-09-22

Heme oxygenases (HO) catalyze the oxidative cleavage of heme to generate biliverdin, CO, and free iron. In humans, heme oxygenase-1 (hHO-1) is overexpressed in tumor tissues, where it helps to protect cancer cells from anticancer agents, while HOs in fungal pathogens, such as Candida albicans, function as the primary means of iron acquisition. Thus, HO can be considered a potential therapeutic target for certain diseases. In this study, we have examined the equilibrium binding of three isocyanides, isopropyl, n-butyl, and benzyl, to the two major human HO isoforms (hHO-1 and hHO-2), Candida albicans HO (CaHmx1), and human cytochrome P450 CYP3A4 using electronic absorption spectroscopy. Isocyanides coordinate to both ferric and ferrous HO-bound heme, with tighter binding by the more hydrophobic isocyanides and 200-300-fold tighter binding to the ferrous form. Benzyl isocyanide was the strongest ligand to ferrous heme in all the enzymes. Because the dissociation constants (KD) of the ligands for ferrous heme-hHO-1 were below the limit of accuracy for equilibrium titrations, stopped-flow kinetic experiments were used to measure the binding parameters of the isocyanides to ferrous hHO-1. Steady-state activity assays showed that benzyl isocyanide was the most potent uncompetitive inhibitor with respect to heme with a KI = 0.15 microM for hHO-1. Importantly, single turnover assays revealed that the reaction was completely stopped by coordination of the isocyanide to the verdoheme intermediate rather than to the ferric heme complex. Much tighter binding of the inhibitor to the verdoheme intermediate differentiates it from inhibition of, for example, CYP3A4 and offers a possible route to more selective inhibitor design.

Isocyanides Inhibit Human Heme Oxygenases at the Verdoheme Stage†

PubMed Central

Evans, John P.; Kandel, Sylvie; Ortiz de Montellano, Paul R.

2010-01-01

Heme oxygenases (HO) catalyze the oxidative cleavage of heme to generate biliverdin, CO, and free iron. In humans, heme oxygenase-1 (hHO-1) is overexpressed in tumor tissues, where it helps to protect cancer cells from anticancer agents, while HOs in fungal pathogens, such as Candida albicans, function as the primary means of iron acquisition. Thus, HO can be considered a potential therapeutic target for certain diseases. In this study, we have examined the equilibrium binding of three isocyanides; isopropyl, n-butyl, and benzyl, to the two major human HO isoforms (hHO-1 and hHO-2), Candida albicans HO (CaHmx1), and human cytochrome P450 CYP3A4 using electronic absorption spectroscopy. Isocyanides coordinate to both ferric and ferrous HO-bound heme, with tighter binding by the more hydrophobic isocyanides, and 200-300-fold tighter binding to the ferrous form. Benzyl isocyanide was the strongest ligand to ferrous heme in all the enzymes. Because the dissociation constants (KD) of the ligands for ferrous heme-hHO-1 were below the limit of accuracy for equilibrium titrations, stopped-flow kinetic experiments were used to measure the binding parameters of the isocyanides to ferrous hHO-1. Steady-state activity assays showed that benzyl isocyanide was the most potent uncompetitive inhibitor with respect to heme with a KI = 0.15 μM for hHO-1. Importantly, single turnover assays revealed that the reaction was completely stopped by coordination of the isocyanide to the verdoheme intermediate rather than to the ferric heme complex. Much tighter binding of the inhibitor to the verdoheme intermediate differentiates it from inhibition of, for example, CYP3A4 and offers a possible route to more selective inhibitor design. PMID:19694439

Comparative effect of propolis of honey bee and some herbal extracts on Candida albicans.

PubMed

Gavanji, Shahin; Larki, Behrouz

2017-03-01

To determine the effect of propolis on Candida albicans and to compare it with the effects of some other herbal extracts and antibiotics on this pathogenic fungi. The extracts of propolis, Thymus vulgaris, Caryophillium aromaticus, Echinophora platyloba, Allium cepa and Cinnamomum zeylanicum were prepared and the antifungi effects of the extracts were examined on Candida albicans ATCC10231 using disc-diffusion assay and micro-broth dilution. The minimum fungicidal concentration (MFC) and minimum inhibitory concentrations (MIC) as well as inhibition zone were evaluated and the anti fungi effects of herbal extracts were compared with amphotricin B and nystatin at the times of 24, 48 and 72 h. Data analysis was performed using t test. Obtained results showed that propolis extract with MIC 90 and MFC equal to 39 and 65 μg/mL, respectively, possess the highest antifungal activity when compared with other studied extracts. The extracts of Allium cepa and Thymus vulgaris, with MFC of 169 and 137 μg/mL, respectively, showed the lowest effects on the fungi. Also nystatin and amphotricin B yielded better effects on the tested fungi compared with the effects of all studied extracts on Candida albicans. Propolis extract is effective in controlling Candida albicans. However, the issue requires further investigation on samples in animals and performing toxicological examinations.

Oropharyngeal candidiasis in children with lymphohematopoietic malignancies in Mashhad, Iran

PubMed Central

Berenji, F; Zabolinejad, N; Badiei, Z; Kakhi, S; Andalib Aliabadi, Z; Ganjbakhsh, M

2015-01-01

Background and Purpose: Over the past years, the role of fungi as a cause of nosocomial infections in hospitalized patients has been accentuated. Candida species constitute an important group of fungi causing diseases in immunocompromised patients. Oropharyngeal candidiasis continues to be a prevalent infection in immunodeficient patients. In this study, we aimed to determine the incidence of oropharyngeal candidiasis in children with lymphohematopoietic malignancies. Materials and Methods: In total, 102 patients with lymphohematopoietic malignancies and 50 healthy controls were examined in terms of Candida infections via direct sampling of the oropharyngeal cavity. Fresh smears were prepared with 10% potassium hydroxide and Gram staining was carried out. Subsequently, the obtained specimens were cultured on Sabouraud dextrose agar for further analysis. Results: The most common Candida species were Candida albicans (31%), other non-C. albicans species (14.7%), C. glabrata (6.8%), and C. krusei (0.98%) in the case group, while in the control group, other non-C. albicans species (10%) and C. albicans (8%) were the most common species. Conclusion: In the present study, Candida species were the most common fungal pathogens in pediatric cancer patients; therefore, efforts should be made to prevent fungemia and fungal pneumonia. Also, non-C. albicans species must be considered as a new risk factor for pediatric cancer patients. PMID:28681002

Oropharyngeal candidiasis in children with lymphohematopoietic malignancies in Mashhad, Iran.

PubMed

Berenji, F; Zabolinejad, N; Badiei, Z; Kakhi, S; Andalib Aliabadi, Z; Ganjbakhsh, M

2015-12-01

Over the past years, the role of fungi as a cause of nosocomial infections in hospitalized patients has been accentuated. Candida species constitute an important group of fungi causing diseases in immunocompromised patients. Oropharyngeal candidiasis continues to be a prevalent infection in immunodeficient patients. In this study, we aimed to determine the incidence of oropharyngeal candidiasis in children with lymphohematopoietic malignancies. In total, 102 patients with lymphohematopoietic malignancies and 50 healthy controls were examined in terms of Candida infections via direct sampling of the oropharyngeal cavity. Fresh smears were prepared with 10% potassium hydroxide and Gram staining was carried out. Subsequently, the obtained specimens were cultured on Sabouraud dextrose agar for further analysis. The most common Candida species were Candida albicans (31%), other non- C. albicans species (14.7%), C. glabrata (6.8%), and C. krusei (0.98%) in the case group, while in the control group, other non- C. albicans species (10%) and C. albicans (8%) were the most common species. In the present study, Candida species were the most common fungal pathogens in pediatric cancer patients; therefore, efforts should be made to prevent fungemia and fungal pneumonia. Also, non -C. albicans species must be considered as a new risk factor for pediatric cancer patients.

21 CFR 173.160 - Candida guilliermondii.

Code of Federal Regulations, 2014 CFR

2014-04-01

...) SECONDARY DIRECT FOOD ADDITIVES PERMITTED IN FOOD FOR HUMAN CONSUMPTION Enzyme Preparations and...: (a) The food additive is the enzyme system of the viable organism Candida guilliermondii and its...

Local, systemic, demographic, and health-related factors influencing pathogenic yeast spectrum and antifungal drug administration frequency in oral candidiasis: a retrospective study.

PubMed

Hertel, Moritz; Schmidt-Westhausen, Andrea Maria; Strietzel, Frank-Peter

2016-09-01

In order to identify oral candidiasis patients being at risk of carrying potentially drug-resistant Candida, the aim of the study was to detect local, systemic, demographic, and health-related factors influencing (I) yeast spectrum composition and (II) antifungal administration frequency. Additionally, the aim was to investigate (III) species shift occurrence. Data from 798 patients (496 females, 302 males; mean age 59.7) with oral candidiasis diagnosed based on positive clinical and microbial findings (species identification and CFU count) between 2006 and 2011 were retrospectively analyzed using Pearson's chi(2) test and regression analysis. Among 958 isolates, Candida albicans was the most frequently detected (76.8 %). Also, species intrinsically resistant to azoles were frequently isolated (15.8 and 17.7 % of isolates and patients). (I) Infections only caused by C. albicans were significantly associated with the use of inhalation steroids (p = 0.001) and antibiotics (p = 0.04), super-infection of lichen planus (p = 0.002), and the absence of removable dentures (p < 0.001). (II) Anti-mycotics were significantly more frequently administered in patients using inhalation steroids (p = 0.001), suffering from asthma/COPD, or smoking heavily (p = 0.003) and if C. albicans and non-albicans species were detected together (p = 0.001). (III) Pathogen composition did not change over time within the examined period (p = 0.239). Different variables enhance the presence of certain Candida and the antifungal prescription frequency. No species shift was evident. The major pathogen in oral candidiasis remains C. albicans. Nevertheless, therapeutic problems may be caused by the frequent presence of species intrinsically resistant to azoles, especially in patients wearing dentures.

Structural and Functional Analysis of Cell Wall-anchored Polypeptide Adhesin BspA in Streptococcus agalactiae*

PubMed Central

Rego, Sara; Heal, Timothy J.; Pidwill, Grace R.; Till, Marisa; Robson, Alice; Lamont, Richard J.; Sessions, Richard B.; Jenkinson, Howard F.; Race, Paul R.; Nobbs, Angela H.

2016-01-01

Streptococcus agalactiae (group B Streptococcus, GBS) is the predominant cause of early-onset infectious disease in neonates and is responsible for life-threatening infections in elderly and immunocompromised individuals. Clinical manifestations of GBS infection include sepsis, pneumonia, and meningitis. Here, we describe BspA, a deviant antigen I/II family polypeptide that confers adhesive properties linked to pathogenesis in GBS. Heterologous expression of BspA on the surface of the non-adherent bacterium Lactococcus lactis confers adherence to scavenger receptor gp340, human vaginal epithelium, and to the fungus Candida albicans. Complementary crystallographic and biophysical characterization of BspA reveal a novel β-sandwich adhesion domain and unique asparagine-dependent super-helical stalk. Collectively, these findings establish a new bacterial adhesin structure that has in effect been hijacked by a pathogenic Streptococcus species to provide competitive advantage in human mucosal infections. PMID:27311712

Association of Genital Infections Other Than Human Papillomavirus with Pre-Invasive and Invasive Cervical Neoplasia

PubMed Central

Mandal, Ranajit; Kundu, Pratip; Biswas, Jaydip

2016-01-01

Human papillomavirus (HPV) is a well-established causative agent of malignancy of the female genital tract and a common Sexually Transmitted Infection. The probable co-factors that prevent spontaneous clearance of HPV and progression to neoplasia are genital tract infections from organisms like Chlamydia, Trichomonas vaginalis etc, smoking, nutritional deficiencies and multiparity. Inflammatory conditions can lead to pre-neoplastic manifestations in the cervical epithelium; however their specific role in cervical carcinogenesis is not yet established. Therefore it is imperative to study the likely association between HPV and co-infection with various common pathogens in the genital tract of women having cervical precancer or cancer. A “Pubmed” search was made for articles in Literature on this topic using the words: Cervical neoplasia, HPV, co-infections, Cervical Intraepithelial Neoplasia (CIN), Trichomonas vaginalis, Candida, Chlamydia and the relevant information obtained was used to draft the review. PMID:27042571

Triclosan Enhances the Clearing of Pathogenic Intracellular Salmonella or Candida albicans but Disturbs the Intestinal Microbiota through mTOR-Independent Autophagy.

PubMed

Wang, Chao; Yu, Zhongyang; Shi, Xiaochen; Tang, Xudong; Wang, Yang; Wang, Xueyan; An, Yanan; Li, Shulin; Li, Yan; Wang, Xuefei; Luan, Wenjing; Chen, Zhaobin; Liu, Mingyuan; Yu, Lu

2018-01-01

Triclosan (TCS) is a broad-spectrum antimicrobial agent, whose well-known antibacterial mechanism is inhibiting lipid synthesis. Autophagy, an innate immune response, is an intracellular process that delivers the cargo including pathogens to lysosomes for degradation. In this study, we first demonstrated that TCS induced autophagy in a dose-dependent manner in non-phagocytic cells (HeLa) and in macrophages (Raw264.7) and in vivo . The western blot results also revealed that TCS induced autophagy via the AMPK/ULK1 and JNK/ERK/p38 pathways independent of mTOR. The immunofluorescence results indicated that TCS up-regulated the expression of the ubiquitin receptors NDP52 and p62 and strengthened the co-localization of these receptors with Salmonella enterica Typhimurium ( S . typhimurium) or Candida albicans ( C. albicans ) in infected MΦ cells. In addition, sub-lethal concentrations of TCS enhanced the clearing of the pathogens S . typhimurium or C. albicans in infected MΦ and in corresponding mouse infection models in vivo . Specifically, we found that a sub-inhibitory concentration of TCS induced autophagy, leading to an imbalance of the intestinal microflora in mice through the analysis of 16s rRNA Sequencing. Together, these results demonstrated that TCS induced autophagy, which enhanced the killing against pathogenic S . typhimurium or C. albicans within mammal cells but broke the balance of the intestinal microflora.

First Nine Cases of Candida auris Infection Reported in Central America: Importance of Acurate Diagnosis and Susceptibility Testing

PubMed Central

Rodriguez, Ana Belen Arauz; Caceres, Diego H; Santiago, Erika; Armstrong, Paige; French, Amalia Rodriguez; Arosemena, Susan; Ramos, Carolina; Espinosa-Bode, Andres; Borace, Jovanna; Hayer, Lizbeth; Cedeño, Israel; Sosa, Nestor; Berkow, Elizabeth L; Lockhart, Shawn R; Jackson, Brendan R; Chiller, Tom

2017-01-01

Abstract Background Candida auris is an emerging multidrug-resistant pathogen associated with invasive infections and high mortality. This report describes the first 9 cases of C. auris in Central America in a hospital in Panama City, Panama, and highlights the challenges of accurate identification and methods for susceptibility testing. Methods Isolates initially identified at a Panama City acute care hospital during July–October 2016 as Candida haemulonii (a common misidentification for C. auris) or Candida species by Vitek® 2 automated system (bioMérieux) were further characterized by molecular methods. Antifungal susceptibility testing was performed and results were compared between standard and reference methodologies. Patient demographic, clinical, and laboratory data were collected from the medical record. Results A total of 14 isolates from 9 hospitalized patients were confirmed as C. auris. Isolates were from urine (11), blood (1), catheter tip (1) and pleural fluid (1). Results of susceptibility testing were highly discrepant between automated and reference techniques for fluconazole (92% resistant vs. 77%, respectively) and amphotericin B (100% vs. 8%). Six (67%) patients were male, and the mean age was 53 years (range 42–78). All patients were admitted to the intensive care unit and were mechanically ventilated. Seven (78%) patients died. Conclusion C. auris is present in Central America. Healthcare facilities in the region should be vigilant for this concerning pathogen, particularly given challenges in its identification and need for infection control precautions. Although automated testing overestimated amphotericin B resistance, most initial isolates were susceptible by reference testing. Disclosures All authors: No reported disclosures.

Antimicrobial and cytotoxic effects of Mexican medicinal plants.

PubMed

Jacobo-Salcedo, Maria del Rosario; Alonso-Castro, Angel Josabad; Salazar-Olivo, Luis A; Carranza-Alvarez, Candy; González-Espíndola, Luis Angel; Domínguez, Fabiola; Maciel-Torres, Sandra Patricia; García-Lujan, Concepción; González-Martínez, Marisela del Rocio; Gómez-Sánchez, Maricela; Estrada-Castillón, Eduardo; Zapata-Bustos, Rocio; Medellin-Milán, Pedro; García-Carrancá, Alejandro

2011-12-01

The antimicrobial effects of the Mexican medicinal plants Guazuma ulmifolia, Justicia spicigera, Opuntia joconostle, O. leucotricha, Parkinsonia aculeata, Phoradendron longifolium, P. serotinum, Psittacanthus calyculatus, Tecoma stans and Teucrium cubense were tested against several human multi-drug resistant pathogens, including three Gram (+) and five Gram (-) bacterial species and three fungal species using the disk-diffusion assay. The cytotoxicity of plant extracts on human cancer cell lines and human normal non-cancerous cells was also evaluated using the MTT assay. Phoradendron longifolium, Teucrium cubense, Opuntia joconostle, Tecoma stans and Guazuma ulmifolia showed potent antimicrobial effects against at least one multidrug-resistant microorganism (inhibition zone > 15 mm). Only Justicia spicigera and Phoradendron serotinum extracts exerted active cytotoxic effects on human breast cancer cells (IC50 < or = 30 microg/mL). The results showed that Guazuma ulmifolia produced potent antimicrobial effects against Candida albicans and Acinetobacter lwoffii, whereas Justicia spicigera and Phoradendron serotinum exerted the highest toxic effects on MCF-7 and HeLa, respectively, which are human cancer cell lines. These three plant species may be important sources of antimicrobial and cytotoxic agents.

Performance of CHROMAGAR candida and BIGGY agar for identification of yeast species

PubMed Central

Yücesoy, Mine; Marol, Serhat

2003-01-01

Background The importance of identifying the pathogenic fungi rapidly has encouraged the development of differential media for the presumptive identification of yeasts. In this study two differential media, CHROMagar Candida and bismuth sulphite glucose glycine yeast agar, were evaluated for the presumptive identification of yeast species. Methods A total number of 270 yeast strains including 169 Candida albicans, 33 C. tropicalis, 24 C. glabrata, 18 C. parapsilosis, 12 C. krusei, 5 Trichosporon spp., 4 C. kefyr, 2 C. lusitaniae, 1 Saccharomyces cerevisiae and 1 Geotrichum candidum were included. The strains were first identified by germ tube test, morphological characteristics on cornmeal tween 80 agar and Vitek 32 and API 20 C AUX systems. In parallel, they were also streaked onto CHROMagar Candida and bismuth sulphite glucose glycine yeast agar plates. The results were read according to the color, morphology of the colonies and the existance of halo around them after 48 hours of incubation at 37°C. Results The sensitivity and specificity values for C. albicans strains were found to be 99.4, 100% for CHROMagar Candida and 87.0, 75.2% for BiGGY agar, respectively. The sensitivity of CHROMagar Candida to identify C. tropicalis, C. glabrata and C. krusei ranged between 90.9 and 100% while the specificity was 100%. The sensitivity rates for BiGGY agar were 66.6 and 100% while the specificity values were found to be 95.4 and 100% for C. tropicalis and C. krusei, respectively. Conclusions It can be concluded that the use of CHROMagar Candida is an easy and reliable method for the presumptive identification of most commonly isolated Candida species especially C. albicans, C. tropicalis and C. krusei. The lower sensitivity and specificity of BiGGY agar to identify commonly isolated Candida species potentially limits the clinical usefulness of this agar. PMID:14613587

Candida albicans Shaving to Profile Human Serum Proteins on Hyphal Surface

PubMed Central

Marín, Elvira; Parra-Giraldo, Claudia M.; Hernández-Haro, Carolina; Hernáez, María L.; Nombela, César; Monteoliva, Lucía; Gil, Concha

2015-01-01

Candida albicans is a human opportunistic fungus and it is responsible for a wide variety of infections, either superficial or systemic. C. albicans is a polymorphic fungus and its ability to switch between yeast and hyphae is essential for its virulence. Once C. albicans obtains access to the human body, the host serum constitutes a complex environment of interaction with C. albicans cell surface in bloodstream. To draw a comprehensive picture of this relevant step in host-pathogen interaction during invasive candidiasis, we have optimized a gel-free shaving proteomic strategy to identify both, human serum proteins coating C. albicans cells and fungi surface proteins simultaneously. This approach was carried out with normal serum (NS) and heat inactivated serum (HIS). We identified 214 human and 372 C. albicans unique proteins. Proteins identified in C. albicans included 147 which were described as located at the cell surface and 52 that were described as immunogenic. Interestingly, among these C. albicans proteins, we identified 23 GPI-anchored proteins, Gpd2 and Pra1, which are involved in complement system evasion and 7 other proteins that are able to attach plasminogen to C. albicans surface (Adh1, Eno1, Fba1, Pgk1, Tdh3, Tef1, and Tsa1). Furthermore, 12 proteins identified at the C. albicans hyphae surface induced with 10% human serum were not detected in other hypha-induced conditions. The most abundant human proteins identified are involved in complement and coagulation pathways. Remarkably, with this strategy, all main proteins belonging to complement cascades were identified on the C. albicans surface. Moreover, we identified immunoglobulins, cytoskeletal proteins, metabolic proteins such as apolipoproteins and others. Additionally, we identified more inhibitors of complement and coagulation pathways, some of them serpin proteins (serine protease inhibitors), in HIS vs. NS. On the other hand, we detected a higher amount of C3 at the C. albicans surface in NS than in HIS, as validated by immunofluorescence. PMID:26696967

Antifungal nanofibers made by controlled release of sea animal derived peptide

NASA Astrophysics Data System (ADS)

Viana, Juliane F. C.; Carrijo, Jéssica; Freitas, Camila G.; Paul, Arghya; Alcaraz, Jarib; Lacorte, Cristiano C.; Migliolo, Ludovico; Andrade, César A.; Falcão, Rosana; Santos, Nuno C.; Gonçalves, Sónia; Otero-González, Anselmo J.; Khademhosseini, Ali; Dias, Simoni C.; Franco, Octávio L.

2015-03-01

Candida albicans is a common human-pathogenic fungal species with the ability to cause several diseases including surface infections. Despite the clear difficulties of Candida control, antimicrobial peptides (AMPs) have emerged as an alternative strategy for fungal control. In this report, different concentrations of antifungal Cm-p1 (Cencritchis muricatus peptide 1) were electrospun into nanofibers for drug delivery. The nanofibers were characterized by mass spectrometry confirming the presence of the peptide on the scaffold. Atomic force microscopy and scanning electronic microscopy were used to measure the diameters, showing that Cm-p1 affects fiber morphology as well as the diameter and scaffold thickness. The Cm-p1 release behavior from the nanofibers demonstrated peptide release from 30 min to three days, leading to effective yeast control in the first 24 hours. Moreover, the biocompatibility of the fibers were evaluated through a MTS assay as well as ROS production by using a HUVEC model, showing that the fibers do not affect cell viability and only nanofibers containing 10% Cm-p1-PVA improved ROS generation. In addition, the secretion of pro-inflammatory cytokines IL-6 and TNF-α by the HUVECs was also slightly modified by the 10% Cm-p1-PVA nanofibers. In conclusion, the electrospinning technique applied here allowed for the manufacture of biodegradable biomimetic nanofibrous extracellular membranes with the ability to control fungal infection.Candida albicans is a common human-pathogenic fungal species with the ability to cause several diseases including surface infections. Despite the clear difficulties of Candida control, antimicrobial peptides (AMPs) have emerged as an alternative strategy for fungal control. In this report, different concentrations of antifungal Cm-p1 (Cencritchis muricatus peptide 1) were electrospun into nanofibers for drug delivery. The nanofibers were characterized by mass spectrometry confirming the presence of the peptide on the scaffold. Atomic force microscopy and scanning electronic microscopy were used to measure the diameters, showing that Cm-p1 affects fiber morphology as well as the diameter and scaffold thickness. The Cm-p1 release behavior from the nanofibers demonstrated peptide release from 30 min to three days, leading to effective yeast control in the first 24 hours. Moreover, the biocompatibility of the fibers were evaluated through a MTS assay as well as ROS production by using a HUVEC model, showing that the fibers do not affect cell viability and only nanofibers containing 10% Cm-p1-PVA improved ROS generation. In addition, the secretion of pro-inflammatory cytokines IL-6 and TNF-α by the HUVECs was also slightly modified by the 10% Cm-p1-PVA nanofibers. In conclusion, the electrospinning technique applied here allowed for the manufacture of biodegradable biomimetic nanofibrous extracellular membranes with the ability to control fungal infection. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr00767d

Oral administration of live- or heat-killed Candida albicans worsened cecal ligation and puncture sepsis in a murine model possibly due to an increased serum (1→3)-β-D-glucan.

PubMed

Panpetch, Wimonrat; Somboonna, Naraporn; Bulan, Dewi Embong; Issara-Amphorn, Jiraphorn; Finkelman, Malcolm; Worasilchai, Navaporn; Chindamporn, Ariya; Palaga, Tanapat; Tumwasorn, Somying; Leelahavanichkul, Asada

2017-01-01

Candida albicans is the most common fungus in the human intestinal microbiota but not in mice. To make a murine sepsis model more closely resemble human sepsis and to explore the role of intestinal C. albicans, in the absence of candidemia, in bacterial sepsis, live- or heat-killed C. albicans was orally administered to mice at 3h prior to cecal ligation and puncture (CLP). A higher mortality rate of CLP was demonstrated with Candida-administration (live- or heat-killed) prior to CLP. Fecal Candida presented only in experiments with live-Candida administration. Despite the absence of candidemia, serum (1→3)-β-D-glucan (BG) was higher in CLP with Candida-administration than CLP-controls (normal saline administration) at 6h and/or 18h post-CLP. Interestingly, fluconazole attenuated the fecal Candida burden and improved survival in mice with live-Candida administration, but not CLP-control. Microbiota analysis revealed increased Bacteroides spp. and reduced Lactobacillus spp. in feces after Candida administration. Additionally, synergy in the elicitation of cytokine production from bone marrow-derived macrophages, in vitro, was demonstrated by co-exposure to heat-killed E. coli and BG. In conclusion, intestinal abundance of fungi and/or fungal-molecules was associated with increased bacterial sepsis-severity, perhaps through enhanced cytokine elicitation induced by synergistic responses to molecules from gut-derived bacteria and fungi. Conversely, reducing intestinal fungal burdens decreased serum BG and attenuated sepsis in our model.

Combination of caspofungin or anidulafungin with antimicrobial peptides results in potent synergistic killing of Candida albicans and Candida glabrata in vitro.

PubMed

Harris, Mark R; Coote, Peter J

2010-04-01

Administering synergistic combinations of antifungals could be a route to overcome problems with toxicity and the development of resistance. Combination of the echinocandins caspofungin or anidulafungin with a range of structurally diverse antimicrobial peptides resulted in potent synergistic killing of Candida spp. in vitro. Fungicidal synergy was measured by calculating fractional inhibitory concentration indices from checkerboard assays as well as loss of viability. Inhibitory combinations of the antifungals did not induce cytotoxicity in vitro. However, in a murine model of systemic candidiasis, co-administration of caspofungin with one example of the cationic peptides tested, ranalexin, did not show enhanced efficacy compared with the single treatments alone. Further study using alternative peptides will identify whether this combination approach could represent a novel treatment for fungal pathogens. (c) 2009 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

Candida Biofilms: Development, Architecture, and Resistance

PubMed Central

CHANDRA, JYOTSNA; MUKHERJEE, PRANAB K.

2015-01-01

Intravascular device–related infections are often associated with biofilms (microbial communities encased within a polysaccharide-rich extracellular matrix) formed by pathogens on the surfaces of these devices. Candida species are the most common fungi isolated from catheter-, denture-, and voice prosthesis–associated infections and also are commonly isolated from contact lens–related infections (e.g., fungal keratitis). These biofilms exhibit decreased susceptibility to most antimicrobial agents, which contributes to the persistence of infection. Recent technological advances have facilitated the development of novel approaches to investigate the formation of biofilms and identify specific markers for biofilms. These studies have provided extensive knowledge of the effect of different variables, including growth time, nutrients, and physiological conditions, on biofilm formation, morphology, and architecture. In this article, we will focus on fungal biofilms (mainly Candida biofilms) and provide an update on the development, architecture, and resistance mechanisms of biofilms. PMID:26350306

Prevalence of pathogenic yeasts and humoral antibodies to candida in diabetic patients.

PubMed Central

Odds, F C; Evans, E G; Taylor, M A; Wales, J K

1978-01-01

The prevalence of oral yeasts and humoral precipitating antibodies to candida was estimated in 204 unselected diabetic patients (172 outpatients and 32 inpatients). Yeasts, mainly Candida albicans, were isolated from the mouths of 41% of the outpatients and precipitins were found in 17.5% although none of the patients had clinically overt candidiasis. The extent of oral yeast colonisation and incidence of antibodies was not related to their antidiabetic treatment or to the duration of their diabetes. It was, however, related to the blood glucose and urine sugar levels at the time they were sampled, the highest incidence being among the diabetic inpatients with high blood glucose levels at the time of sampling and the lowest among outpatients with normal blood glucose levels at the time of sampling. There was no such correlation when diabetic control over the previous 12-month period was considered. PMID:711913

Ultra-fast low concentration detection of Candida pathogens utilizing high resolution micropore chips.

PubMed

Mulero, Rafael; Lee, Dong Heun; Kutzler, Michele A; Jacobson, Jeffrey M; Kim, Min Jun

2009-01-01

Although Candida species are the fourth most common cause of nosocomial blood stream infections in the United States, early diagnostic tools for invasive candidemia are lacking. Due to an increasing rate of candidemia, a new screening system is needed to detect the Candida species in a timely manner. Here we describe a novel method of detection using a solid-state micro-scale pore similar to the operational principles of a Coulter counter. With a steady electrolyte current flowing through the pore, measurements are taken of changes in the current corresponding to the shape of individual yeasts as they translocate or travel through the pore. The direct ultra-fast low concentration electrical addressing of C. albicans has established criteria for distinguishing individual yeast based on their structural properties, which may reduce the currently used methods' complexity for both identification and quantification capabilities in mixed blood samples.

Ultra-Fast Low Concentration Detection of Candida Pathogens Utilizing High Resolution Micropore Chips

PubMed Central

Mulero, Rafael; Lee, Dong Heun; Kutzler, Michele A.; Jacobson, Jeffrey M.; Kim, Min Jun

2009-01-01

Although Candida species are the fourth most common cause of nosocomial blood stream infections in the United States, early diagnostic tools for invasive candidemia are lacking. Due to an increasing rate of candidemia, a new screening system is needed to detect the Candida species in a timely manner. Here we describe a novel method of detection using a solid-state micro-scale pore similar to the operational principles of a Coulter counter. With a steady electrolyte current flowing through the pore, measurements are taken of changes in the current corresponding to the shape of individual yeasts as they translocate or travel through the pore. The direct ultra-fast low concentration electrical addressing of C. albicans has established criteria for distinguishing individual yeast based on their structural properties, which may reduce the currently used methods’ complexity for both identification and quantification capabilities in mixed blood samples. PMID:22573974

Clinical, microbiological, and experimental animal studies of Candida lipolytica.

PubMed Central

Walsh, T J; Salkin, I F; Dixon, D M; Hurd, N J

1989-01-01

Candida lipolytica was recovered from six patients in three different clinical centers. The index isolate caused a persistent fungemia with catheter-associated Candida thrombophlebitis, the second isolate was from a polymicrobial sinusitis, and the remaining four isolates were involved in tissue colonization. These and 20 other isolates were consistent in their morphological and physiological characteristics. All formed true hyphae and blastoconidia on cornmeal-Tween 80 agar and all assimilated glucose, glycerol, and erythritol. In a murine model of disseminated candidiasis, the index isolate that caused clinical fungemia caused no mortality and produced only two lesions on a kidney, as determined at necropsy. The nine isolates selected for in vitro antifungal susceptibility studies had intermediate susceptibilities to amphotericin B but were susceptible to ketoconazole. We conclude that C. lipolytica is a weakly virulent pathogen which may require an intravascular foreign body to cause fungemia. Images PMID:2745702

Antifungal activity of four honeys of different types from Algeria against pathogenic yeast: Candida albicans and Rhodotorula sp.

PubMed

Moussa, Ahmed; Noureddine, Djebli; Saad, Aissat; Abdelmelek, Meslem; Abdelkader, Benhalima

2012-07-01

To evaluate the antifungal activity of four honeys of different types from Algeria against pathogenic yeast i.e. Candida albicans (C. albicans) and Rhodotorula sp. Four Algeria honeys of different botanical origin were analyzed to test antifungal effect against C. albicans, and Rhodotorula sp. Different concentrations (undiluted, 10%, 30%, 50% and 70% w/v) of honey were studied in vitro for their antifugal activity using C. albicans and Rhodotorula sp. as fungal strains. The range of the diameter of zone of inhibition of various concentrations of tested honeys was (7-23 mm) for Rhodotorula sp., while C. albicans showed clearly resistance towards all concentrations used. The MICs of tested honey concentrations against C. albicans and Rhodotorula sp. were (70.09-93.48)% and (4.90-99.70)% v/v, respectively. This study demonstrates that, in vitro, these natural products have clearly an antifungal activity against Rhodotorula sp. and C. albicans.

A CRISPR Cas9-based gene drive platform for genetic interaction analysis in Candida albicans

PubMed Central

Shapiro, Rebecca S.; Chavez, Alejandro; Porter, Caroline B. M.; Hamblin, Meagan; Kaas, Christian S.; DiCarlo, James E.; Zeng, Guisheng; Xu, Xiaoli; Revtovich, Alexey V.; Kirienko, Natalia V.; Wang, Yue; Church, George M.; Collins, James J.

2018-01-01

Candida albicans is the leading cause of fungal infections; yet, complex genetic interaction analysis remains cumbersome in this diploid pathogen. Here, we developed a CRISPR-Cas9-based ‘gene drive array’ (GDA) platform to facilitate efficient genetic analysis in C. albicans. In our system, a modified DNA donor molecule acts as a selfish genetic element, replaces the targeted site, and propagates to replace additional wild-type loci. Using mating-competent C. albicans haploids, each carrying a different gene drive disabling a gene of interest, we are able to create diploid strains that are homozygous double-deletion mutants. We generate double-gene deletion libraries to demonstrate this technology, targeting antifungal efflux and biofilm adhesion factors. We screen these libraries to identify virulence regulators and determine how genetic networks shift under diverse conditions. This platform transforms our ability to perform genetic interaction analysis in C. albicans and is readily extended to other fungal pathogens. PMID:29062088

Antifungal activity of four honeys of different types from Algeria against pathogenic yeast: Candida albicans and Rhodotorula sp.

PubMed Central

Moussa, Ahmed; Noureddine, Djebli; Saad, Aissat; Abdelmelek, Meslem; Abdelkader, Benhalima

2012-01-01

Objective To evaluate the antifungal activity of four honeys of different types from Algeria against pathogenic yeast i.e. Candida albicans (C. albicans) and Rhodotorula sp. Methods Four Algeria honeys of different botanical origin were analyzed to test antifungal effect against C. albicans, and Rhodotorula sp. Different concentrations (undiluted, 10%, 30%, 50% and 70% w/v) of honey were studied in vitro for their antifugal activity using C. albicans and Rhodotorula sp. as fungal strains. Results The range of the diameter of zone of inhibition of various concentrations of tested honeys was (7–23 mm) for Rhodotorula sp., while C. albicans showed clearly resistance towards all concentrations used. The MICs of tested honey concentrations against C. albicans and Rhodotorula sp. were (70.09–93.48)% and (4.90–99.70)% v/v, respectively. Conclusions This study demonstrates that, in vitro, these natural products have clearly an antifungal activity against Rhodotorula sp. and C. albicans. PMID:23569970

D-Cateslytin: a new antifungal agent for the treatment of oral Candida albicans associated infections.

PubMed

Dartevelle, Pauline; Ehlinger, Claire; Zaet, Abdurraouf; Boehler, Christian; Rabineau, Morgane; Westermann, Benoit; Strub, Jean-Marc; Cianferani, Sarah; Haïkel, Youssef; Metz-Boutigue, Marie-Hélène; Marban, Céline

2018-06-18

The excessive use of antifungal agents, compounded by the shortage of new drugs being introduced into the market, is causing the accumulation of multi-resistance phenotypes in many fungal strains. Consequently, new alternative molecules to conventional antifungal agents are urgently needed to prevent the emergence of fungal resistance. In this context, Cateslytin (Ctl), a natural peptide derived from the processing of Chromogranin A, has already been described as an effective antimicrobial agent against several pathogens including Candida albicans. In the present study, we compared the antimicrobial activity of two conformations of Ctl, L-Ctl and D-Ctl against Candida albicans. Our results show that both D-Ctl and L-Ctl were potent and safe antifungal agents. However, in contrast to L-Ctl, D-Ctl was not degraded by proteases secreted by Candida albicans and was also stable in saliva. Using video microscopy, we also demonstrated that D-Ctl can rapidly enter C. albicans, but is unable to spread within a yeast colony unless from a mother cell to a daughter cell during cellular division. Besides, we revealed that the antifungal activity of D-Ctl could be synergized by voriconazole, an antifungal of reference in the treatment of Candida albicans related infections. In conclusion, D-Ctl can be considered as an effective, safe and stable antifungal and could be used alone or in a combination therapy with voriconazole to treat Candida albicans related diseases including oral candidosis.

Study of the prevalence and association of ocular chlamydial conjunctivitis in women with genital infection by Chlamydia trachomatis, Mycoplasma genitalium and Candida albicans attending outpatient clinic.

PubMed

Khattab, Rania Abdelmonem; Abdelfattah, Maha Mohssen

2016-01-01

To determine the association between chlamydial conjunctivitis and genital infection by Chlamydia trachomatis, Mycoplasma genitalium and Candida albicans, in addition to the possible relationship between cultured bacterial pathogens and oculogenital chlamydial infection. This study was performed on 100 (50 symptomatic and 50 asymptomatic) women attending the Gynecological and Obstetric outpatient clinic of Alzahra hospital, Alazhar University. Simultaneously a conjunctival swab was taken from these patients. Polymerase chain reaction (PCR) was done on DNA extracted from both vaginal and conjunctival swab samples. Culture for both vaginal and conjunctival swabs was also done. Candida albicans was the predominant organism isolated by culture in 20% and 40% of conjunctival and vaginal swabs respectively. By the PCR method, ocular Chlamydia trachomatis was present in 60% of symptomatic women, while genital Chlamydia trachomatis infection was present in 30% of symptomatic women. The results of this method also indicated that 25/50 (50%) vaginal swabs were positive with PCR for Candida albicans versus 15/50 (30%) were PCR positive in conjunctival swab. Mycoplasma genitalium was present in only 10% of vaginal swabs. Concomitant oculogenital PCR positive results for Chlamydia trachomatis and Candida albicans were 30% and 28% respectively. Ocular Chlamydia trachomatis was associated with genital Chlamydia trachomatis in a high percentage of women followed by Candida albicans. Cultured bacterial organisms do not play a role in enhancement of Chlamydia trachomatis infection.

Immune-Response Patterns and Next Generation Sequencing Diagnostics for the Detection of Mycoses in Patients with Septic Shock—Results of a Combined Clinical and Experimental Investigation

PubMed Central

Decker, Sebastian O.; Sigl, Annette; Grumaz, Christian; Stevens, Philip; Vainshtein, Yevhen; Zimmermann, Stefan; Weigand, Markus A.; Hofer, Stefan; Sohn, Kai; Brenner, Thorsten

2017-01-01

Fungi are of increasing importance in sepsis. However, culture-based diagnostic procedures are associated with relevant weaknesses. Therefore, culture- and next-generation sequencing (NGS)-based fungal findings as well as corresponding plasma levels of β-d-glucan, interferon gamma (INF-γ), tumor necrosis factor alpha (TNF-α), interleukin (IL)-2, -4, -6, -10, -17A, and mid-regional proadrenomedullin (MR-proADM) were evaluated in 50 septic patients at six consecutive time points within 28 days after sepsis onset. Furthermore, immune-response patterns during infections with Candida spp. were studied in a reconstituted human epithelium model. In total, 22% (n = 11) of patients suffered from a fungal infection. An NGS-based diagnostic approach appeared to be suitable for the identification of fungal pathogens in patients suffering from fungemia as well as in patients with negative blood cultures. Moreover, MR-proADM and IL-17A in plasma proved suitable for the identification of patients with a fungal infection. Using RNA-seq., adrenomedullin (ADM) was shown to be a target gene which is upregulated early after an epithelial infection with Candida spp. In summary, an NGS-based diagnostic approach was able to close the diagnostic gap of routinely used culture-based diagnostic procedures, which can be further facilitated by plasmatic measurements of MR-proADM and IL-17A. In addition, ADM was identified as an early target gene in response to epithelial infections with Candida spp. PMID:28820494

Probiotic yeast Saccharomyces boulardii (nom. nud.) modulates adhesive properties of Candida glabrata.

PubMed

Tomičić, Zorica; Zupan, Jure; Matos, Tadeja; Raspor, Peter

2016-11-01

Following the widespread use of immunosuppressive therapy together with broad-spectrum antimycotic therapy, the frequency of mucosal and systemic infections caused by the pathogenic yeast Candida glabrata has increased in the past decades. Due to the resistance of C. glabrata to existing azole drugs, it is very important to look for new strategies helping the treatment of such fungal diseases. In this study, we investigated the effect of the probiotic yeast Saccharomyces boulardii (nom. nud.) on C. glabrata adhesion at different temperatures, pH values, and in the presence of fluconazole, itraconazole and amphotericin B. We also studied the adhesion of C. glabrata co-culture with Candida krusei, Saccharomyces cerevisiae, two bacterial probiotics Lactobacillus rhamnosus and Lactobacillus casei The method used to assess adhesion was crystal violet staining. Our results showed that despite the nonadhesiveness of S. boulardii cells, this probiotic significantly affected the adherence ability of C. glabrata This effect was highly dependent on C. glabrata strain and was either antagonistic or synergistic. Regarding the extrinsic factors, temperature did not indicate any significant influence on this S. boulardii modulatory effect, while at high pH and at increased concentrations of antimycotics, S. boulardii did not manage to repress the adhesion of C. glabrata strains. The experiments of C. glabrata co-cultures with other species showed that the adhesiveness of two separate cultures could not be used to predict the adhesiveness of their co-culture. © The Author 2016. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Evaluation of MALDI-TOF-MS for the Identification of Yeast Isolates Causing Bloodstream Infection.

PubMed

Turhan, Ozge; Ozhak-Baysan, Betil; Zaragoza, Oscar; Er, Halil; Sarıtas, Zubeyde Eres; Ongut, Gozde; Ogunc, Dilara; Colak, Dilek; Cuenca-Estrella, Manuel

2017-04-01

Infections due to Candida species are major causes of morbidity and mortality in humans, causing a diverse spectrum of clinical disease ranging from superficial and mucosal infections to invasive disease. Several authors have demonstrated that mortality is closely linked to both timing of therapy and/or source control. The rapid identification of pathogenic species is helpful to start timely and effective antifungal therapy. The aim of this study was to assess the performance of the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) system for the correct and rapid identification of yeast isolates causing bloodstream infection. Between January 2014 and January 2015, a total of 117 yeast like organisms isolated from blood culture samples of 117 episodes from 102 patients who had blood stream infections were included in the study. The isolates were identified by MALDI-TOF MS. The results were compared with those obtained by the standard mycological methods and/or sequence analysis. One hundred and seventeen yeast isolates including 115 Candida spp and two non-Candida yeasts were analysed. The Biotyper correctly identified 115 (98.3%) isolates to the genus level and 102 (87.2%) isolates to the species level using the manufacturer's recommended cutoff scores. The Bruker Biotyper is a rapid, easy, inexpensive, and highly reliable system for the identification of yeast isolates. Early identification with MALDI-TOF MS would save time for determination of antifungal susceptibility and proper treatment strategy. The expansion of the database of the library by addition of less common species will improve the performance of the system.

A stable hybrid containing haploid genomes of two obligate diploid Candida species.

PubMed

Chakraborty, Uttara; Mohamed, Aiyaz; Kakade, Pallavi; Mugasimangalam, Raja C; Sadhale, Parag P; Sanyal, Kaustuv

2013-08-01

Candida albicans and Candida dubliniensis are diploid, predominantly asexual human-pathogenic yeasts. In this study, we constructed tetraploid (4n) strains of C. albicans of the same or different lineages by spheroplast fusion. Induction of chromosome loss in the tetraploid C. albicans generated diploid or near-diploid progeny strains but did not produce any haploid progeny. We also constructed stable heterotetraploid somatic hybrid strains (2n + 2n) of C. albicans and C. dubliniensis by spheroplast fusion. Heterodiploid (n + n) progeny hybrids were obtained after inducing chromosome loss in a stable heterotetraploid hybrid. To identify a subset of hybrid heterodiploid progeny strains carrying at least one copy of all chromosomes of both species, unique centromere sequences of various chromosomes of each species were used as markers in PCR analysis. The reduction of chromosome content was confirmed by a comparative genome hybridization (CGH) assay. The hybrid strains were found to be stably propagated. Chromatin immunoprecipitation (ChIP) assays with antibodies against centromere-specific histones (C. albicans Cse4/C. dubliniensis Cse4) revealed that the centromere identity of chromosomes of each species is maintained in the hybrid genomes of the heterotetraploid and heterodiploid strains. Thus, our results suggest that the diploid genome content is not obligatory for the survival of either C. albicans or C. dubliniensis. In keeping with the recent discovery of the existence of haploid C. albicans strains, the heterodiploid strains of our study can be excellent tools for further species-specific genome elimination, yielding true haploid progeny of C. albicans or C. dubliniensis in future.

Yeasts of the genital region of patients attending the dermatology service at Hospital São Paulo, Brazil.

PubMed

Bentubo, Henri Donnarumma Levy; Mantovani, Ariane; Yamashita, Jane Tomimori; Gambale, Walderez; Fischman, Olga

2015-01-01

The knowledge of the diversity of yeasts that make up the skin microbiota of human beings is essential for the efficient monitoring of infections to which a person may be predisposed. This study identified yeasts comprising the genital skin microbiota of patients attending the Dermatology Service at the Hospital São Paulo-UNIFESP, Brazil. Samples were collected from the genital region of each patient and cultured on Sabouraud dextrose agar. Individual colonies were carefully transferred to tubes daily. Yeasts were identified based on classical methodologies and confirmed using a commercial kit. Eighty-three patients were included in the study. Approximately 80% were women and 20% were men. The average age was 55 years. Hypertension, diabetes, kidney transplant and AIDS were the main underlying diseases reported by the patients. The most prevalent yeasts were Candida parapsilosis (36.1%), Rhodotorula mucilaginosa (9.2%), Rhodotorula glutinis (8.3%), Candida tropicalis (5.5%) and Trichosporon inkin (1.8%). Approximately 78% of the isolates were obtained in pure cultures. Trichosporon inkin was isolated only from women, in contrast to literature describing a high prevalence in males. Our results suggest that Candida albicans is not the main yeast found on genital skin as previously thought, and opportunistic pathogens such as C. parapsilosis, C. tropicalis, Rhodotorula spp. and T. inkin make up the genital skin microbiota, representing a risk for infection in immunocompromised subjects. These results also indicate that women are carriers of T. inkin, the etiological agent of white piedra and trichosporonosis. Copyright © 2013 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

Chemical composition, antioxidant and antimicrobial effects of Tunisian Limoniastrum guyonianum Durieu ex Boiss extracts.

PubMed

Bouzidi, Amel; Benzarti, Anissa; Arem, Amira El; Mahfoudhi, Adel; Hammami, Saoussen; Gorcii, Mohamed; Mastouri, Maha; Hellal, Ahmed Noureddine; Mighri, Zine

2016-07-01

In the present investigation, extracts obtained from L. guyonianum Durieu ex Boiss. aerial parts were used to evaluate total phenolic, flavonoid and tannin contents. A study of antioxidant activities of the prepared samples was carried out on the basis of 1,1-Diphenyl-2-picrylhydrazyl (DPPH), 2-2'-azino-bis-(3-ethylbenz-thiazoline-6-sulfonic acid) (ABTS+.) and ferric reducing antioxidant power (FRAP) assays. Moreover, the efficiency of methanolic, chloroformic and petroleum ether extracts and the deriving fractions from the methanolic extract was tested against human bacterial and fungal pathogenic strains using micro dilution method in 96 multiwell microtiter plate. Furthermore, leaves and stems extracts were subjected to RP-HPLC for phenolic compounds identification. Results showed that polyphenolic contents and antioxidant activities varied considerably as function of solvent polarity. Moreover, antiradical capacities against DPPH, ABTS(+.) and reducing power were maxima in methanol aerial parts extract which showed the highest polyphenol contents (134mg CE/g DW). The antimicrobial activities showed that methanolic, chloroformic and petroleum ether extracts were found to be most potent against Pseudomonas aeruginosa and Staphylococcus aureus with MIC values of 23 and 46μ.mL(-1), respectively. The fractions F(13) and F(16) have a great antifungal potential against Candida glabrata, Candida krusei and Candida parapsilesis (MIC=39μ.mL(-1)). The RP-HPLC analysis lead the identification of gallic, procatechuic and trans-cinnamic acids, methyl-4-hydroxybenzoate, n-propyl-3,4,5-trihydroxybenzoate, epicatechin, naringin and myricetin in L. guyonianum Durieu ex Boiss. leaves and stems extracts.

Anti-Candida albicans natural products, sources of new antifungal drugs: A review.

PubMed

Zida, A; Bamba, S; Yacouba, A; Ouedraogo-Traore, R; Guiguemdé, R T

2017-03-01

Candida albicans is the most prevalent fungal pathogen in humans. Due to the development of drug resistance, there is today a need for new antifungal agents for the efficient management of C. albicans infections. Therefore, we reviewed antifungal activity, mechanisms of action, possible synergism with antifungal drugs of all natural substances experimented to be efficient against C. albicans for future. An extensive and systematic review of the literature was undertaken and all relevant abstracts and full-text articles analyzed and included in the review. A total of 111 documents were published and highlighted 142 anti-C. albicans natural products. These products are mostly are reported in Asia (44.37%) and America (28.17%). According to in vitro model criteria, from the 142 natural substances, antifungal activity can be considered as important for 40 (28.20%) and moderate for 24 (16.90%). Sixteen products have their antifungal activity confirmed by in vivo gold standard experimentation. Microbial natural products, source of antifungals, have their antifungal mechanism well described in the literature: interaction with ergosterol (polyenes), inhibition 1,3-β-d-glucan synthase (Echinocandins), inhibition of the synthesis of cell wall components (chitin and mannoproteins), inhibition of sphingolipid synthesis (serine palmitoyltransferase, ceramide synthase, inositol phosphoceramide synthase) and inhibition of protein synthesis (sordarins). Natural products from plants mostly exert their antifungal effects by membrane-active mechanism. Some substances from arthropods are also explored to act on the fungal membrane. Interestingly, synergistic effects were found between different classes of natural products as well as between natural products and azoles. Search for anti-C. albicans new drugs is promising since the list of natural substances, which disclose activity against this yeast is today long. Investigations must be pursued not only to found more new anti-Candida compounds from plants and organisms but also to carried out details on molecules from already known anti-Candida compounds and to more elucidate mechanisms of action. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Emerging fungal infections among children: A review on its clinical manifestations, diagnosis, and prevention

PubMed Central

Jain, Akansha; Jain, Shubham; Rawat, Swati

2010-01-01

The incidence of fungal infections is increasing at an alarming rate, presenting an enormous challenge to healthcare professionals. This increase is directly related to the growing population of immunocompromised individuals especially children resulting from changes in medical practice such as the use of intensive chemotherapy and immunosuppressive drugs. Although healthy children have strong natural immunity against fungal infections, then also fungal infection among children are increasing very fast. Virtually not all fungi are pathogenic and their infection is opportunistic. Fungi can occur in the form of yeast, mould, and dimorph. In children fungi can cause superficial infection, i.e., on skin, nails, and hair like oral thrush, candida diaper rash, tinea infections, etc., are various types of superficial fungal infections, subcutaneous fungal infection in tissues under the skin and lastly it causes systemic infection in deeper tissues. Most superficial and subcutaneous fungal infections are easily diagnosed and readily amenable to treatment. Opportunistic fungal infections are those that cause diseases exclusively in immunocompromised individuals, e.g., aspergillosis, zygomycosis, etc. Systemic infections can be life-threatening and are associated with high morbidity and mortality. Because diagnosis is difficult and the causative agent is often confirmed only at autopsy, the exact incidence of systemic infections is difficult to determine. The most frequently encountered pathogens are Candida albicans and Aspergillus spp. But other fungi such as non-albicans Candida spp. are increasingly important. PMID:21180463

Adherence of Candida sp. to host tissues and cells as one of its pathogenicity features.

PubMed

Modrzewska, Barbara; Kurnatowski, Piotr

2015-01-01

The ability of Candida sp. cells to adhere to the mucosal surfaces of various host organs as well as synthetic materials is an important pathogenicity feature of those fungi which contributes to the development of infection. This property varies depending on the species of the fungus and is the greatest for C. albicans. The process of adhesion depends on plenty of factors related to the fungal and host cells as well as environmental conditions. The main adhesins present on the fungal cell wall are: Als, Epa, Hwp1, but also Eap1, Sun41, Csh1 and probably Hyr1; for adhesion significant are also secreted aspartyl proteases Sap. Various researchers specify a range of genes which contribute to adhesion, such as: CZF1, EFG1, TUP1, TPK1, TPK2, HGC1, RAS1, RIM101, VPS11, ECM1, CKA2, BCR1, BUD2, RSR1, IRS4, CHS2, SCS7, UBI4, UME6, TEC1 and GAT2. Influence for adherence have also heat shock proteins Hsp70, Mediator Middle domain subunit Med31 and morphological transition. Among factors affecting adhesion related to host cells it is necessary to mention fibronectins and integrins (receptors for Candida sp. adhesins), type of epithelial cells, their morphology and differentiation phase. To a lesser degree influence on adhesion have non-specific factors and environmental conditions.

[Results of mycologic studies of donated breast milk].

PubMed

Blaschke-Hellmessen, R; Henker, J; Futschik, M

1991-03-01

From 1968 to 1989 altogether 37,000 specimens of donated and collected mother's milk were mycologically examined by means of a liquid medium (twofold concentrated Raulin solution). The yearly incidence of Candida albicans varied between 8.5 and 5.2%. 25% respectively 14.8% of the donors (n = 60 respectively 813) had delivered milk to the human milk bank which was contaminated by Candida albicans. The mother's milk was primarily contaminated by the donor's own suckling baby. 92.3% of these infants were infected with Candida albicans in the mouth and/or rectum and/or on the skin. Candida albicans was also detected in 46.2% on the nipples of the mothers. It is recommended to transport donated mother's milk at temperatures of 4-8 degrees C and to store the milk at -20 degrees C until the mycological examination is finished to exclude samples contaminated by Candida albicans. Judging our experience donated human milk to be fed in raw state should be regularly controlled mycologically. If the donated milk contains Candida albicans, the donation of milk should be interrupted and an antifungal treatment of the donor and her baby should be performed.

The MARVEL domain protein Nce102 regulates actin organization and invasive growth of Candida albicans.

PubMed

Douglas, Lois M; Wang, Hong X; Konopka, James B

2013-11-26

Invasive growth of the fungal pathogen Candida albicans into tissues promotes disseminated infections in humans. The plasma membrane is essential for pathogenesis because this important barrier mediates morphogenesis and invasive growth, as well as secretion of virulence factors, cell wall synthesis, nutrient import, and other processes. Previous studies showed that the Sur7 tetraspan protein that localizes to MCC (membrane compartment occupied by Can1)/eisosome subdomains of the plasma membrane regulates a broad range of key functions, including cell wall synthesis, morphogenesis, and resistance to copper. Therefore, a distinct tetraspan protein found in MCC/eisosomes, Nce102, was investigated. Nce102 belongs to the MARVEL domain protein family, which is implicated in regulating membrane structure and function. Deletion of NCE102 did not cause the broad defects seen in sur7Δ cells. Instead, the nce102Δ mutant displayed a unique phenotype in that it was defective in forming hyphae and invading low concentrations of agar but could invade well in higher agar concentrations. This phenotype was likely due to a defect in actin organization that was observed by phalloidin staining. In support of this, the invasive growth defect of a bni1Δ mutant that mislocalizes actin due to lack of the Bni1 formin was also reversed at high agar concentrations. This suggests that a denser matrix provides a signal that compensates for the actin defects. The nce102Δ mutant displayed decreased virulence and formed abnormal hyphae in mice. These studies identify novel ways that Nce102 and the physical environment surrounding C. albicans regulate morphogenesis and pathogenesis. The plasma membrane promotes virulence of the human fungal pathogen Candida albicans by acting as a protective barrier around the cell and mediating dynamic activities, such as morphogenesis, cell wall synthesis, secretion of virulence factors, and nutrient uptake. To better understand how the plasma membrane contributes to virulence, we analyzed a set of eight genes encoding MARVEL family proteins that are predicted to function in membrane organization. Interestingly, deletion of one gene, NCE102, caused a strong defect in formation of invasive hyphal growth in vitro and decreased virulence in mice. The nce102Δ mutant cells showed defects in actin organization that underlie the morphogenesis defect, since mutation of a known regulator of actin organization caused a similar defect. These studies identify a novel way in which the plasma membrane regulates the actin cytoskeleton and contributes to pathogenesis.

[The interaction of pathogenic microorganisms with the sorbent polymethylsiloxane].

PubMed

Dikova, I G; Il'chenko, O I; Ruban, V I; Samodumova, I M; Sidel'nikova, L F

1993-01-01

The method of electron microscopy has been used to study adhesion of the microbic cells of standard strains of Staphylococcus aureus, Escherichia coli and fungi of genus Candida on the organosilicon sorbent polymethylsiloxane (PMS) and medicamentous complex containing it. This complex contains furazolidone and metronidazole immobilized on silver ions-modified PMS. It is shown that the adhesion of microorganisms is accompanied by their destruction whose rate on pure PMS and medicamentous complex is different. Using experimental data the assumptions are advanced concerning the mechanism of the PMS interaction with Gram-positive and Gram-negative microorganisms as well as with fungi of genus Candida.

The Candida albicans Biofilm Matrix: Composition, Structure and Function.

PubMed

Pierce, Christopher G; Vila, Taissa; Romo, Jesus A; Montelongo-Jauregui, Daniel; Wall, Gina; Ramasubramanian, Anand; Lopez-Ribot, Jose L

2017-03-01

A majority of infections caused by Candida albicans -the most frequent fungal pathogen-are associated with biofilm formation. A salient feature of C. albicans biofilms is the presence of the biofilm matrix. This matrix is composed of exopolymeric materials secreted by sessile cells within the biofilm, in which all classes of macromolecules are represented, and provides protection against environmental challenges. In this review, we summarize the knowledge accumulated during the last two decades on the composition, structure, and function of the C. albicans biofilm matrix. Knowledge of the matrix components, its structure, and function will help pave the way to novel strategies to combat C. albicans biofilm infections.

Differential Effects of Vitamins A and D on the Transcriptional Landscape of Human Monocytes during Infection

PubMed Central

Klassert, Tilman E.; Bräuer, Julia; Hölzer, Martin; Stock, Magdalena; Riege, Konstantin; Zubiría-Barrera, Cristina; Müller, Mario M.; Rummler, Silke; Skerka, Christine; Marz, Manja; Slevogt, Hortense

2017-01-01

Vitamin A and vitamin D are essential nutrients with a wide range of pleiotropic effects in humans. Beyond their well-documented roles in cellular differentiation, embryogenesis, tissue maintenance and bone/calcium homeostasis, both vitamins have attracted considerable attention due to their association with-immunological traits. Nevertheless, our knowledge of their immunomodulatory potential during infection is restricted to single gene-centric studies, which do not reflect the complexity of immune processes. In the present study, we performed a comprehensive RNA-seq-based approach to define the whole immunomodulatory role of vitamins A and D during infection. Using human monocytes as host cells, we characterized the differential role of both vitamins upon infection with three different pathogens: Aspergillus fumigatus, Candida albicans and Escherichia coli. Both vitamins showed an unexpected ability to counteract the pathogen-induced transcriptional responses. Upon infection, we identified 346 and 176 immune-relevant genes that were regulated by atRA and vitD, respectively. This immunomodulatory activity was dependent on the inflammatory stimulus, allowing us to distinguish regulatory patterns which were specific for each stimulatory setting. Moreover, we explored possible direct and indirect mechanisms of vitamin-mediated regulation of the immune response. Our findings highlight the importance of vitamin-monitoring in critically ill patients. Moreover, our results underpin the potential of atRA and vitD as therapeutic options for anti-inflammatory treatment. PMID:28094291

Gold nanoparticles synthesized by Brassica oleracea (Broccoli) acting as antimicrobial agents against human pathogenic bacteria and fungi

NASA Astrophysics Data System (ADS)

Piruthiviraj, Prakash; Margret, Anita; Krishnamurthy, Poornima Priyadharsani

2016-04-01

Production of antimicrobial agents through the synthesis of gold nanoparticles using green technology has been extensively made consistent by various researchers; yet, this study uses the flower bud's aqueous extracts of Brassica oleracea (Broccoli) as a reducing agent for chloroauric acid (1 mM). After 30 min of incubation, synthesis of gold nanoparticles (AuNps) was observed by a change in extract color from pale yellow to purple color. Synthesis of AuNps was confirmed in UV-visible spectroscopy at the range of approximately 560 nm. The SEM analysis showed the average nanoparticles size of 12-22 nm. The antimicrobial activity of AuNps was analyzed by subjecting it to human pathogenic bacteria (Gram-positive Staphylococcus aureus and Gram-negative Klebsiella pneumonia) and fungi (Aspergillus flavus, Aspergillus niger and Candida albicans) using disc diffusion method. The broccoli-synthesized AuNps showed the efficient antibacterial and antifungal activity of above-mentioned microbes. It was confirmed that AuNps have the best antimicrobial agent compared to the standard antibiotics (Gentamicin and Fluconazole). When the concentrations of AuNps were increased (10, 25, and 50 µg/ml), the sensitivity zone also increased for all the tested microbes. The synthesized AuNps are capable of rendering high antimicrobial efficacy and, hence, have a great potential in the preparation of drugs used against major bacterial and fungal diseases in humans.

Evaluation of esterase and hemolysin activities of different Candida species isolated from vulvovaginitis cases in Lorestan Province, Iran

PubMed Central

Noori, Maryam; Dakhili, Mohammad; Sepahvand, Asghar; Davari, Nader

2017-01-01

Background and Purpose: Annually affecting millions of women, vulvovaginal candidiasis (VVC) is commonly described by signs and symptoms of vulvovaginal inflammation in the presence of Candida species. Today, the detection of the virulence factors plays a major role in the understanding of pathogenesis of candidiasis and helps produce new anticandidial drugs to improve its treatment efficiency. Herein, we aimed to evaluate the esterase and hemolysin activities of the vaginal isolates of Candida and their relationship with the presence of VVC. Materials and Methods: One-hundred vaginal clinical specimens were randomly collected during September-December 2016. The target population consisted of married women suspected of VVC who presented to health centers in Lorestan Province, Iran. In this study, the esterase activity and hemolysin production of Candida clinical isolates were evaluated using the Tween 80 opacity test and the plate assay, respectively. Results: The most frequent Candida species was C. albicans (66; 66%), followed by C. glabrata (11; 11%) and C. tropicalis (11; 11%). The highest esterase activity was found in C. krusei (75%), followed by C. albicans (68.2%) and C. glabrata (54.5%). The greater part of the positive esterase isolates had Pz 4+ scores. Among the Candida species, C. albicans (22.7%), C. glabrata (63.6%), and C. krusei (50%) were found to have the highest rates of alpha, beta, and gamma hemolysin production, respectively. The level of hemolytic activity in 51% of the Candida species was Pz 4+ scores. Conclusion: According to our results, the higher expression rates of both enzymes in C. albicans species relative to those of non-albicans Candidate species can partly reflect the role of the virulence factors involved in C. albicans pathogenicity. PMID:29707672

Evaluation of esterase and hemolysin activities of different Candida species isolated from vulvovaginitis cases in Lorestan Province, Iran.

PubMed

Noori, Maryam; Dakhili, Mohammad; Sepahvand, Asghar; Davari, Nader

2017-12-01

Annually affecting millions of women, vulvovaginal candidiasis (VVC) is commonly described by signs and symptoms of vulvovaginal inflammation in the presence of  Candida  species. Today, the detection of the virulence factors plays a major role in the understanding of pathogenesis of candidiasis and helps produce new anticandidial drugs to improve its treatment efficiency. Herein, we aimed to evaluate the esterase and hemolysin activities of the vaginal isolates of Candida and their relationship with the presence of VVC. One-hundred vaginal clinical specimens were randomly collected during September-December 2016. The target population consisted of married women suspected of VVC who presented to health centers in Lorestan Province, Iran. In this study, the esterase activity and hemolysin production of Candida clinical isolates were evaluated using the Tween 80 opacity test and the plate assay, respectively. The most frequent Candida species was C. albicans (66; 66%), followed by C. glabrata (11; 11%) and C. tropicalis (11; 11%). The highest esterase activity was found in C. krusei (75%), followed by C. albicans (68.2%) and C. glabrata (54.5%). The greater part of the positive esterase isolates had Pz 4+ scores. Among the Candida species, C. albicans (22.7 % ), C. glabrata (63.6%), and C. krusei (50%) were found to have the highest rates of alpha, beta, and gamma hemolysin production, respectively. The level of hemolytic activity in 51% of the Candida species was Pz 4+ scores. According to our results, the higher expression rates of both enzymes in C. albicans species relative to those of non-albicans Candidate species can partly reflect the role of the virulence factors involved in C. albicans pathogenicity.

Evaluation of two matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) systems for the identification of Candida species.

PubMed

Lacroix, C; Gicquel, A; Sendid, B; Meyer, J; Accoceberry, I; François, N; Morio, F; Desoubeaux, G; Chandenier, J; Kauffmann-Lacroix, C; Hennequin, C; Guitard, J; Nassif, X; Bougnoux, M-E

2014-02-01

Candida spp. are responsible for severe infections in immunocompromised patients and those undergoing invasive procedures. The accurate identification of Candida species is important because emerging species can be associated with various antifungal susceptibility spectra. Conventional methods have been developed to identify the most common pathogens, but have often failed to identify uncommon species. Several studies have reported the efficiency of matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for the identification of clinically relevant Candida species. In this study, we evaluated two commercially available MALDI-TOF systems, Andromas™ and Bruker Biotyper™, for Candida identification in routine diagnosis. For this purpose, we investigated 1383 Candida isolates prospectively collected in eight hospital laboratories during routine practice. MALDI-TOF MS results were compared with those obtained using conventional phenotypic methods. Analysis of rDNA gene sequences with internal transcribed regions or D1-D2 regions is considered the reference standard for identification. Both MALDI-TOF MS systems could accurately identify 98.3% of the isolates at the species level (1359/1383 for Andromas™; 1360/1383 for Bruker Biotyper™) vs. 96.5% for conventional techniques. Furthermore, whereas conventional methods failed to identify rare or emerging species, these were correctly identified by MALDI-TOF MS. Both MALDI-TOF MS systems are accurate and cost-effective alternatives to conventional methods for mycological identification of clinically relevant Candida species and should improve the diagnosis of fungal infections as well as patient management. © 2013 The Authors Clinical Microbiology and Infection © 2013 European Society of Clinical Microbiology and Infectious Diseases.

Clostridium difficile shows no trade-off between toxin and spore production within the human host.

PubMed

Blanco, Natalia; Walk, Seth; Malani, Anurag N; Rickard, Alexander; Benn, Michele; Eisenberg, Marisa; Zhang, Min; Foxman, Betsy

2018-05-01

This study aimed to describe the correlation between Clostridium difficile spore and toxin levels within the human host. In addition, we assessed whether overgrowth of Candida albicans modified this association. We measured toxin, spore and Candida albicans levels among 200 successively collected stool samples that tested positive for C. difficile, and PCR ribotyped these C. difficile isolates. Analysis of variance and linear regression were used to test the association between spore and toxin levels. Kruskal-Wallis tests and t-tests were used to compare the association between spore or toxin levels and host, specimen, or pathogen characteristics. C. difficile toxin and spore levels were positively associated (P<0.001); this association did not vary significantly with C. albicans overgrowth [≥5 logs of C. albicans colony-forming units (c.f.u.) g -1 ]. However, ribotypes 027 and 078-126 were significantly associated with higher levels of toxin and spores, and C. albicans overgrowth. The strong positive association observed between in vivo levels of C. difficile toxin and spores suggests that patients with more severe C. difficile infections may have increased spore production, enhancing C. difficile transmission. Although, on average, spore levels were higher in toxin-positive samples than in toxin-negative/PCR-positive samples, spores were found in almost all toxin-negative samples. The ubiquity of spore production among toxin-negative and formed stool samples emphasizes the importance of following infection prevention and control measures for all C. difficile-positive patients during their entire hospital stay.