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Sample records for pathogenic staphylococcal species

  1. Persistence of staphylococcal species and genotypes in the bovine udder.

    PubMed

    Mørk, T; Jørgensen, H J; Sunde, M; Kvitle, B; Sviland, S; Waage, S; Tollersrud, T

    2012-09-14

    Staphylococci are a major cause of intramammary infections (IMI) in ruminants. The main aim of this study was to investigate staphylococcal IMI in dairy cattle with emphasis on persistence and distribution of staphylococcal species and genotypes. With a sampling interval of 4-8 weeks, over a year, 4030 samples from 206 cows in 4 herds were collected. Coagulase-negative staphylococci (CNS) and Staphylococcus aureus were detected in 13.2% and 4.2% of the samples, respectively. Selected CNS isolates from quarter milk samples were identified to species level using sodA sequencing. Staphylococcus chromogenes (32%) and Staphylococcus simulans (25%) predominated. The proportion of S. chromogenes was greater in primiparous (52%) than in multiparous cows (12%), while the opposite was the case for Staphylococcus epidermidis (6% and 21%, respectively). Isolates from possibly persistent IMI were selected for pulsed-field gel electrophoresis (PFGE). Six staphylococcal species were found to cause persistent IMI; S. aureus, S. chromogenes, S. simulans, S. epidermidis, Staphylococcus haemolyticus and Staphylococcus warneri. It was shown that several pulsotypes (PTs) within each species were associated with persistent infections, but only a few were spread and caused persistent IMI in multiple cows within a herd. Of special interest was the observation that only one, or a few, strains of each species caused persistent IMI in multiple cows within a same herd. This indicates strain differences with respect to transmissibility and pathogenicity. PMID:22503603

  2. Automated ribotyping to distinguish the different non Sau/ non Sep staphylococcal emerging pathogens in orthopedic implant infections.

    PubMed

    Campoccia, D; Baldassarri, L; An, Y H; Kang, Q K; Pirini, V; Gamberini, S; Pegreffi, F; Montanaro, L; Arciola, C R

    2006-04-01

    Several species belonging to Staphylococcus genus, other than Staphylococcus aureus and Staphylococcus epidermidis (non Sau/ non Sep species), exhibit increasing abilities as opportunistic pathogens in the colonisation of periprosthetic tissues. Consequently, the availability of means for accurate identification is crucial to assess the pathogenic characteristics and to clarify clinical relevance of the individual species. Here, 146 clinical staphylococcal isolates belonging to non Sau/ non Sep species from prosthesis-associated orthopedic infections were analyzed by conventional enzymatic galleries and by automated ribotyping. Twelve different species were recognised: S. capitis, S. caprae, S. cohnii, S. equorum, S. haemolyticus, S. hominis, S. lugdunensis, S. pasteuri, S. sciuri, S. simulans, S. warneri, S. xylosus. Ribotype identifications were compared with the phenotypes obtained by the Api 20 Staph system and/or ID 32 Staph system. ID 32 Staph profiles were more consistent with ribotyping results than Api Staph profiles. Across the different staphylococcal species investigated, correct identifications with Api Staph were 45%, while with ID 32 Staph they were 59%. It has, however, to be mentioned that ID 32 Staph was mostly applied to discriminate unmatched ribotyping and Api Staph identifications, thus to a subpopulation of strains with "atypical" metabolic profile. Automated ribotyping provided a correct identification for 91% of the isolates. These results confirm automated ribotyping as a convenient rapid technique, still subject to improvements, which will accurately and rapidly recognise the newly emerging staphylococcal pathogens in implant-related orthopedic infections. PMID:16705611

  3. Diversity and evolution of oligopeptide permease systems in staphylococcal species.

    PubMed

    Yu, Dongliang; Pi, Borui; Yu, Meihong; Wang, Yanfei; Ruan, Zhi; Feng, Ye; Yu, Yunsong

    2014-07-01

    Several oligopeptide permease (Opp) systems have been found in staphylococcal species, including Opp1-4, Opp3' and the arginine catabolic mobile element (ACME)-encoded Opp system (ACME-Opp). They confer upon bacteria the increasing fitness, but their evolutionary histories remain unclear. In this work, we performed a genome-wide identification of Opp systems in staphylococcal species. Novel Opp systems were identified, including the duplicate of Opp4 in Staphylococcus pseudintermedius and the ACME-Opp-like systems in coagulase-negative staphylococci (CoNS). Phylogenetic analysis revealed that all of the identified Opp systems were derived from Opp3 system by operon duplication during species divergence, while lateral gene transfer might also confer to the dissemination of Opp in staphylococci. In addition, we proposed an improved theory on evolution of ACME: the Opp and arginine-deiminase systems were firstly transferred from Staphylococcus haemolyticus to Staphylococcus epidermidis independently; in S. epidermidis they were assembled together and then transferred to Staphylococcus aureus. PMID:24793159

  4. A Novel MSCRAMM Subfamily in Coagulase Negative Staphylococcal Species

    PubMed Central

    Arora, Srishtee; Uhlemann, Anne-Catrin; Lowy, Franklin D.; Hook, Magnus

    2016-01-01

    Coagulase negative staphylococci (CoNS) are important opportunistic pathogens. Staphylococcus epidermidis, a coagulase negative staphylococcus, is the third leading cause of nosocomial infections in the US. Surface proteins like Microbial Surface Components Recognizing Adhesive Matrix Molecules (MSCRAMMs) are major virulence factors of pathogenic gram positive bacteria. Here, we identified a new chimeric protein in S. epidermidis, that we call SesJ. SesJ represents a prototype of a new subfamily of MSCRAMMs. Structural predictions show that SesJ has structural features characteristic of a MSCRAMM along with a N-terminal repeat region and an aspartic acid containing C-terminal repeat region, features that have not been previously observed in staphylococcal MSCRAMMs but have been found in other surface proteins from gram positive bacteria. We identified and analyzed structural homologs of SesJ in three other CoNS. These homologs of SesJ have an identical structural organization but varying sequence identities within the domains. Using flow cytometry, we also show that SesJ is expressed constitutively on the surface of a representative S. epidermidis strain, from early exponential to stationary growth phase. Thus, SesJ is positioned to interact with protein targets in the environment and plays a role in S. epidermidis virulence. PMID:27199900

  5. Genetic engineering of untransformable coagulase-negative staphylococcal pathogens.

    PubMed

    Winstel, Volker; Kühner, Petra; Rohde, Holger; Peschel, Andreas

    2016-05-01

    Coagulase-negative staphylococci (CoNS) are recognized as significant opportunistic pathogens. However, current knowledge of virulence mechanisms is very limited because a significant proportion of CoNS are refractory to available techniques for DNA transformation. We describe an efficient protocol for plasmid transfer using bacteriophage Φ187, which can transduce plasmid DNA to a wide range of CoNS from a unique, engineered Staphylococcus aureus strain. The use of a restriction-deficient, modification-proficient S. aureus PS187 mutant, which has a CoNS-type bacteriophage surface receptor, allows plasmid transfer to CoNS even when they are refractory to electroporation. Once the Φ187 titer reaches 10(9) plaque-forming units per milliliter, plasmid transfer can be accomplished within 1-2 d. Thus, our protocol is a major technical advance offering attractive opportunities for research on CoNS-mediated infections. PMID:27101516

  6. Whole-Genome Sequencing of Staphylococcus haemolyticus Uncovers the Extreme Plasticity of Its Genome and the Evolution of Human-Colonizing Staphylococcal Species

    PubMed Central

    Takeuchi, Fumihiko; Watanabe, Shinya; Baba, Tadashi; Yuzawa, Harumi; Ito, Teruyo; Morimoto, Yuh; Kuroda, Makoto; Cui, Longzhu; Takahashi, Mikio; Ankai, Akiho; Baba, Shin-ichi; Fukui, Shigehiro; Lee, Jean C.; Hiramatsu, Keiichi

    2005-01-01

    Staphylococcus haemolyticus is an opportunistic bacterial pathogen that colonizes human skin and is remarkable for its highly antibiotic-resistant phenotype. We determined the complete genome sequence of S.haemolyticus to better understand its pathogenicity and evolutionary relatedness to the other staphylococcal species. A large proportion of the open reading frames in the genomes of S.haemolyticus, Staphylococcus aureus, and Staphylococcus epidermidis were conserved in their sequence and order on the chromosome. We identified a region of the bacterial chromosome just downstream of the origin of replication that showed little homology among the species but was conserved among strains within a species. This novel region, designated the “oriC environ,” likely contributes to the evolution and differentiation of the staphylococcal species, since it was enriched for species-specific nonessential genes that contribute to the biological features of each staphylococcal species. A comparative analysis of the genomes of S.haemolyticus, S.aureus, and S.epidermidis elucidated differences in their biological and genetic characteristics and pathogenic potentials. We identified as many as 82 insertion sequences in the S.haemolyticus chromosome that probably mediated frequent genomic rearrangements, resulting in phenotypic diversification of the strain. Such rearrangements could have brought genomic plasticity to this species and contributed to its acquisition of antibiotic resistance. PMID:16237012

  7. Phosphatase-novobiocin-mannose-inhibition test (PNMI-test) for routine identification of the coagulase-negative staphylococcal urinary tract pathogens S. epidermidis and S. saprophyticus.

    PubMed

    Schmidt, H; Naumann, G

    1990-04-01

    A modified Kloos/Schleifer-scheme proved to be useful in identifying coagulase-negative staphylococci isolated from urine. S. epidermidis (44.2%) and S. saprophyticus (21.5%) were the most frequent species. Analysis of patients confirmed both species as urinary pathogens. Using an abbreviated scheme of 6 characteristics, S. saprophyticus was mis-classified in 19.5% of cases. A Phosphatase-Novobiocin-Mannose-Inhibition Test (PNMI-Test) together with a high NaCl concentration (10%) in combination with a coagulase test seems to be an acceptable compromise for routine identification of the three most important staphylococcal urinary tract pathogens, S. aureus, S. epidermidis, and S. saprophyticus. The technical and financial expenditure can be reduced considerably, because an extended identification has to be applied only to strains which cannot be identified by the PNMI-Test.

  8. Phosphatase-novobiocin-mannose-inhibition test (PNMI-test) for routine identification of the coagulase-negative staphylococcal urinary tract pathogens S. epidermidis and S. saprophyticus.

    PubMed

    Schmidt, H; Naumann, G

    1990-04-01

    A modified Kloos/Schleifer-scheme proved to be useful in identifying coagulase-negative staphylococci isolated from urine. S. epidermidis (44.2%) and S. saprophyticus (21.5%) were the most frequent species. Analysis of patients confirmed both species as urinary pathogens. Using an abbreviated scheme of 6 characteristics, S. saprophyticus was mis-classified in 19.5% of cases. A Phosphatase-Novobiocin-Mannose-Inhibition Test (PNMI-Test) together with a high NaCl concentration (10%) in combination with a coagulase test seems to be an acceptable compromise for routine identification of the three most important staphylococcal urinary tract pathogens, S. aureus, S. epidermidis, and S. saprophyticus. The technical and financial expenditure can be reduced considerably, because an extended identification has to be applied only to strains which cannot be identified by the PNMI-Test. PMID:2163255

  9. Staphylococcal Biofilms

    PubMed Central

    Otto, Michael

    2009-01-01

    Staphylococcus epidermidis and S. aureus are the most frequent causes of nosocomial infections and infections on indwelling medical devices, which characteristically involve biofilms. Recent advances in staphylococcal molecular biology have provided more detailed insight into the basis of biofilm formation in these opportunistic pathogens. A series of surface proteins mediate initial attachment to host matrix proteins, which is followed by the expression of a cationic glucosamine-based exopolysaccharide that aggregates the bacterial cells. In some cases, proteins may function as alternative aggregating substances. Furthermore, surfactant peptides have now been recognized as key factors involved in generating the 3-dimensional structure of a staphylococcal biofilm by cell-cell disruptive forces, which eventually may lead to the detachment of entire cell clusters. Transcriptional profiling experiments have defined the specific physiology of staphylococcal biofilms and demonstrated that biofilm resistance to antimicrobials is due to gene-regulated processes. Finally, novel animal models of staphylococcal biofilm-associated infection have given us important information on which factors define biofilm formation in vivo. These recent advances constitute an important basis for the development of anti-staphylococcal drugs and vaccines. PMID:18453278

  10. [The comparative characteristic of the microflora species composition in the tympanic cavity, nasal mucous membrane and external ear mucosa in the course of experimental suppurative staphylococcal otitis].

    PubMed

    Dolgov, V A

    2014-01-01

    The objective of the present work was to study the species composition of microflora in the suppurative exudate from the tympanic cavity in the course of development of experimental suppurative staphylococcal otitis and to identify the initial sites of migration of secondary pathogens. The experiments were carried out on 20 adult rabbits showing no signs of "spontaneous" otitis. Experimental staphylococcal suppurative otitis was induced in 17 of these animals. The microbiological study included isolation and identification of pure bacterial cultures with the use of the classical method. The initial sites of migration of secondary pathogens were detected from the results of comparison of the species composition of microflora in tympanic exudate and the mucous membrane of the nearest anatomical regions, such as the nasal cavity an external auditory canal. The data obtained indicate that suppurative exudate from the tympanic cavity is populated by polyflora containing secondary pathogens, besides the principal ones (Staphylococci). The large amounts of secondary pathogens penetrate into the tympanic cavity from the mucous membranes of the nasal cavity and nasopharynx. It is concluded that the rhinotubal system is the major pathway through which pathogenic microflora migrates into the middle ear.

  11. 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

  12. Identification of staphylococcal species based on variations in protein sequences (mass spectrometry) and DNA sequence (sodA microarray).

    PubMed

    Kooken, Jennifer; Fox, Karen; Fox, Alvin; Altomare, Diego; Creek, Kim; Wunschel, David; Pajares-Merino, Sara; Martínez-Ballesteros, Ilargi; Garaizar, Javier; Oyarzabal, Omar; Samadpour, Mansour

    2014-02-01

    This report is among the first using sequence variation in newly discovered protein markers for staphylococcal (or indeed any other bacterial) speciation. Variation, at the DNA sequence level, in the sodA gene (commonly used for staphylococcal speciation) provided excellent correlation. Relatedness among strains was also assessed using protein profiling using microcapillary electrophoresis and pulsed field electrophoresis. A total of 64 strains were analyzed including reference strains representing the 11 staphylococcal species most commonly isolated from man (Staphylococcus aureus and 10 coagulase negative species [CoNS]). Matrix assisted time of flight ionization/ionization mass spectrometry (MALDI TOF MS) and liquid chromatography-electrospray ionization tandem mass spectrometry (LC ESI MS/MS) were used for peptide analysis of proteins isolated from gel bands. Comparison of experimental spectra of unknowns versus spectra of peptides derived from reference strains allowed bacterial identification after MALDI TOF MS analysis. After LC-MS/MS analysis of gel bands bacterial speciation was performed by comparing experimental spectra versus virtual spectra using the software X!Tandem. Finally LC-MS/MS was performed on whole proteomes and data analysis also employing X!tandem. Aconitate hydratase and oxoglutarate dehydrogenase served as marker proteins on focused analysis after gel separation. Alternatively on full proteomics analysis elongation factor Tu generally provided the highest confidence in staphylococcal speciation.

  13. Staphylococcus jettensis sp. nov., a coagulase-negative staphylococcal species isolated from human clinical specimens.

    PubMed

    De Bel, Annelies; Van Hoorde, Koenraad; Wybo, Ingrid; Vandoorslaer, Kristof; Echahidi, Fedoua; De Brandt, Evie; Schumann, Peter; Ieven, Margareta; Soetens, Oriane; Piérard, Denis; Vandamme, Peter

    2013-09-01

    Eight coagulase-negative, novobiocin-susceptible staphylococcal strains were isolated from human clinical specimens at two different Belgian medical facilities. All strains were non-motile, Gram-stain-positive, catalase-positive cocci. DNA G+C content, peptidoglycan type, menaquinone pattern, the presence of teichoic acid and cellular fatty acid composition were in agreement with the characteristics of species of the genus Staphylococcus. Sequencing of the 16S rRNA gene and four housekeeping genes (dnaJ, tuf, gap and rpoB) demonstrated that these strains constitute a separate taxon within the genus Staphylococcus. Less than 41% DNA-DNA hybridization with the most closely related species of the genus Staphylococcus (Staphylococcus haemolyticus, Staphylococcus hominis and Staphlococcus lugdunensis) was observed. Key biochemical characteristics that allowed these bacteria to be distinguished from their nearest phylogenetic neighbours are arginine dihydrolase positivity, ornithine decarboxylase negativity and inability to produce acid aerobically from D-mannose, α-lactose and turanose. Acid is produced aerobically from trehalose. Based on these results, a novel species of the genus Staphylococcus is described and named Staphylococcus jettensis sp. nov. The type strain is SEQ110(T) ( =LMG 26879(T) =CCUG 62657(T) =DSM 26618(T)).

  14. The diversities of staphylococcal species, virulence and antibiotic resistance genes in the subclinical mastitis milk from a single Chinese cow herd.

    PubMed

    Xu, Jia; Tan, Xiao; Zhang, Xinyu; Xia, Xiaoli; Sun, Huaichang

    2015-11-01

    Staphylococci are the leading pathogens of bovine mastitis which is difficult to control. However, the published data on the prevalence of staphylococcal species, virulence and antibiotic resistance genes in bovine mastitis from China are limited. In this study, 104 out of 209 subclinical mastitis milk samples from a single Chinese dairy herd were cultured-positive for staphylococci (49.8%), which were further identified as coagulase-positive staphylococci (CPS) or coagulase-negative staphylococci (CNS). According to the partial tuf and/or 16S rRNA gene sequence, the 28 CPS isolates were confirmed to be Staphylococcus aureus (26.9%), and 76 CNS isolates were assigned to 13 different species (73.1%) with Staphylococcus arlettae, Staphylococcus sciuri, Staphylococcus xylosus and Staphylococcus chromogenes as the dominant species. In the 28 S. aureus isolates, the most prevalent general virulence genes were coa, Ig and eno (100%), followed by hla (96.4%), hlb (92.9%), fib (92.9%), clfA (89.3%), clfB (85.7%) and nuc (85.7%). Both exotoxin and biofilm-associated genes were significantly less prevalent than the previously reported. Although 19 different virulence gene patterns were found, only one was dominant (32.1%). The prevalence of blaZ (82.1%) or mecA gene (35.7%) was much higher than the previously reported. In the 76 CNS isolates, the virulence genes were significantly less prevalent than that in the S. aureus isolates. Among the 4 main CNS species, S. chromogenes (n = 12) was the only species with high percentage (75%) of blaZ gene, while S. sciuri (n = 12) was the only species with the high percentage (66.7%) of mecA gene. The most of antibiotic resistance genes were present as multi-resistance genes, and the antibiotic resistances were attributed by different resistance genes between resistant S. aureus and CNS isolates. These data suggest that the prevalence of staphylococcal species, virulence and antibiotic resistance in the mastitis milk from the Chinese

  15. The diversities of staphylococcal species, virulence and antibiotic resistance genes in the subclinical mastitis milk from a single Chinese cow herd.

    PubMed

    Xu, Jia; Tan, Xiao; Zhang, Xinyu; Xia, Xiaoli; Sun, Huaichang

    2015-11-01

    Staphylococci are the leading pathogens of bovine mastitis which is difficult to control. However, the published data on the prevalence of staphylococcal species, virulence and antibiotic resistance genes in bovine mastitis from China are limited. In this study, 104 out of 209 subclinical mastitis milk samples from a single Chinese dairy herd were cultured-positive for staphylococci (49.8%), which were further identified as coagulase-positive staphylococci (CPS) or coagulase-negative staphylococci (CNS). According to the partial tuf and/or 16S rRNA gene sequence, the 28 CPS isolates were confirmed to be Staphylococcus aureus (26.9%), and 76 CNS isolates were assigned to 13 different species (73.1%) with Staphylococcus arlettae, Staphylococcus sciuri, Staphylococcus xylosus and Staphylococcus chromogenes as the dominant species. In the 28 S. aureus isolates, the most prevalent general virulence genes were coa, Ig and eno (100%), followed by hla (96.4%), hlb (92.9%), fib (92.9%), clfA (89.3%), clfB (85.7%) and nuc (85.7%). Both exotoxin and biofilm-associated genes were significantly less prevalent than the previously reported. Although 19 different virulence gene patterns were found, only one was dominant (32.1%). The prevalence of blaZ (82.1%) or mecA gene (35.7%) was much higher than the previously reported. In the 76 CNS isolates, the virulence genes were significantly less prevalent than that in the S. aureus isolates. Among the 4 main CNS species, S. chromogenes (n = 12) was the only species with high percentage (75%) of blaZ gene, while S. sciuri (n = 12) was the only species with the high percentage (66.7%) of mecA gene. The most of antibiotic resistance genes were present as multi-resistance genes, and the antibiotic resistances were attributed by different resistance genes between resistant S. aureus and CNS isolates. These data suggest that the prevalence of staphylococcal species, virulence and antibiotic resistance in the mastitis milk from the Chinese

  16. Bap-dependent biofilm formation by pathogenic species of Staphylococcus: evidence of horizontal gene transfer?

    PubMed

    Tormo, M Angeles; Knecht, Erwin; Götz, Friedrich; Lasa, Iñigo; Penadés, José R

    2005-07-01

    The biofilm-associated protein (Bap) is a surface protein implicated in biofilm formation by Staphylococcus aureus isolated from chronic mastitis infections. The bap gene is carried in a putative composite transposon inserted in SaPIbov2, a mobile staphylococcal pathogenicity island. In this study, bap orthologue genes from several staphylococcal species, including Staphylococcus epidermidis, Staphylococcus chromogenes, Staphylococcus xylosus, Staphylococcus simulans and Staphylococcus hyicus, were identified, cloned and sequenced. Sequence analysis comparison of the bap gene from these species revealed a very high sequence similarity, suggesting the horizontal gene transfer of SaPIbov2 amongst them. However, sequence analyses of the flanking region revealed that the bap gene of these species was not contained in the SaPIbov2 pathogenicity island. Although they did not contain the icaADBC operon, all the coagulase-negative staphylococcal isolates harbouring bap were strong biofilm producers. Disruption of the bap gene in S. epidermidis abolished its capacity to form a biofilm, whereas heterologous complementation of a biofilm-negative strain of S. aureus with the Bap protein from S. epidermidis bestowed the capacity to form a biofilm on a polystyrene surface. Altogether, these results demonstrate that Bap orthologues from coagulase-negative staphylococci induce an alternative mechanism of biofilm formation that is independent of the PIA/PNAG exopolysaccharide.

  17. Transfer of Plasmid DNA to Clinical Coagulase-Negative Staphylococcal Pathogens by Using a Unique Bacteriophage

    PubMed Central

    Kühner, Petra; Krismer, Bernhard; Peschel, Andreas; Rohde, Holger

    2015-01-01

    Genetic manipulation of emerging bacterial pathogens, such as coagulase-negative staphylococci (CoNS), is a major hurdle in clinical and basic microbiological research. Strong genetic barriers, such as restriction modification systems or clustered regularly interspaced short palindromic repeats (CRISPR), usually interfere with available techniques for DNA transformation and therefore complicate manipulation of CoNS or render it impossible. Thus, current knowledge of pathogenicity and virulence determinants of CoNS is very limited. Here, a rapid, efficient, and highly reliable technique is presented to transfer plasmid DNA essential for genetic engineering to important CoNS pathogens from a unique Staphylococcus aureus strain via a specific S. aureus bacteriophage, Φ187. Even strains refractory to electroporation can be transduced by this technique once donor and recipient strains share similar Φ187 receptor properties. As a proof of principle, this technique was used to delete the alternative transcription factor sigma B (SigB) via allelic replacement in nasal and clinical Staphylococcus epidermidis isolates at high efficiencies. The described approach will allow the genetic manipulation of a wide range of CoNS pathogens and might inspire research activities to manipulate other important pathogens in a similar fashion. PMID:25616805

  18. Transfer of plasmid DNA to clinical coagulase-negative staphylococcal pathogens by using a unique bacteriophage.

    PubMed

    Winstel, Volker; Kühner, Petra; Krismer, Bernhard; Peschel, Andreas; Rohde, Holger

    2015-04-01

    Genetic manipulation of emerging bacterial pathogens, such as coagulase-negative staphylococci (CoNS), is a major hurdle in clinical and basic microbiological research. Strong genetic barriers, such as restriction modification systems or clustered regularly interspaced short palindromic repeats (CRISPR), usually interfere with available techniques for DNA transformation and therefore complicate manipulation of CoNS or render it impossible. Thus, current knowledge of pathogenicity and virulence determinants of CoNS is very limited. Here, a rapid, efficient, and highly reliable technique is presented to transfer plasmid DNA essential for genetic engineering to important CoNS pathogens from a unique Staphylococcus aureus strain via a specific S. aureus bacteriophage, Φ187. Even strains refractory to electroporation can be transduced by this technique once donor and recipient strains share similar Φ187 receptor properties. As a proof of principle, this technique was used to delete the alternative transcription factor sigma B (SigB) via allelic replacement in nasal and clinical Staphylococcus epidermidis isolates at high efficiencies. The described approach will allow the genetic manipulation of a wide range of CoNS pathogens and might inspire research activities to manipulate other important pathogens in a similar fashion.

  19. Meningitis - staphylococcal

    MedlinePlus

    Staphylococcal meningitis is caused by Staphylococcus bacteria. When it is caused by Staphylococcus aureus or Staphylococcus epidermidis bacteria, it usually develops as a complication of surgery or ...

  20. Investigations on the efficacy of routinely used phenotypic methods compared to genotypic approaches for the identification of staphylococcal species isolated from companion animals in Irish veterinary hospitals

    PubMed Central

    2013-01-01

    Background Identification of Staphylococci to species level in veterinary microbiology is important to inform therapeutic intervention and management. We report on the efficacy of three routinely used commercial phenotypic methods for staphylococcal species identification, namely API Staph 32 (bioMérieux), RapID (Remel) and Staph-Zym (Rosco Diagnostica) compared to genotyping as a reference method to identify 52 staphylococcal clinical isolates (23 coagulase positive; 29 coagulase negative) from companion animals in Irish veterinary hospitals. Results Genotyping of a 412 bp fragment of the staphylococcal tuf gene and coagulase testing were carried out on all 52 veterinary samples along with 7 reference strains. In addition, genotyping of the staphylococcal rpoB gene, as well as PCR-RFLP of the pta gene, were performed to definitively identify members of the Staphylococcus intermedius group (SIG). The API Staph 32 correctly identified all S. aureus isolates (11/11), 83% (10/12) of the SIG species, and 66% (19/29) of the coagulase negative species. RapID and Staph-Zym correctly identified 61% (14/23) and 0% (0/23) respectively of the coagulase-positives, and 10% (3/29) and 3% (1/29) respectively of the coagulase-negative species. Conclusions Commercially available phenotypic species identification tests are inadequate for the correct identification of both coagulase negative and coagulase positive staphylococcal species from companion animals. Genotyping using the tuf gene sequence is superior to phenotyping for identification of staphylococcal species of animal origin. However, use of PCR-RFLP of pta gene or rpoB sequencing is recommended as a confirmatory method for discriminating between SIG isolates. PMID:23635328

  1. Phenol-soluble modulins – critical determinants of staphylococcal virulence

    PubMed Central

    Cheung, Gordon Y. C.; Joo, Hwang-Soo; Chatterjee, Som S.; Otto, Michael

    2014-01-01

    Phenol-soluble modulins (PSMs) are a recently discovered family of amphipathic, alpha-helical peptides that have multiple roles in staphylococcal pathogenesis and contribute to a large extent to the pathogenic success of virulent staphylococci, such as Staphylococcus aureus. PSMs may cause lysis of many human cell types including leukocytes and erythrocytes, stimulate inflammatory responses, and contribute to biofilm development. PSMs appear to have an original role in the commensal lifestyle of staphylococci, where they facilitate growth and spreading on epithelial surfaces. Aggressive, cytolytic PSMs seem to have evolved from that original role and are mainly expressed in highly virulent S. aureus. Here we will review the biochemistry, genetics and role of PSMs in the commensal and pathogenic lifestyles of staphylococci, discuss how diversification of PSMs defines the aggressiveness of staphylococcal species, and evaluate potential avenues to target PSMs for drug development against staphylococcal infections. PMID:24372362

  2. Pathogenic mechanisms of the hypocalcemia of the staphylococcal toxic-shock syndrome.

    PubMed

    Chesney, R W; McCarron, D M; Haddad, J G; Hawker, C D; DiBella, F P; Chesney, P J; Davis, J P

    1983-04-01

    Hypocalcemia is a common finding in TSS. This has been causally related to the hypoalbuminemia of TSS. To more clearly define the mechanism responsible for this hypocalcemia, we examined the serum concentrations of CaT, Ca+ +, iCT, albumin, and DBP in 28 women meeting the case-study definition of TSS. Mean CaT was 2.18 +/- 0.36 mM/L (S.D.), Ca+ + was 0.93 +/- 0.19 mM/L, and iCT was 1941 +/- 978 pg/ml; all were significantly different (p less than 0.01) from the normal values of CaT (2.38 +/- 0.09), Ca+ + (1.09 +/- 0.04) and iCT (less than 30 to 135). A significant inverse correlation was found between iCT and both CaT and Ca+ +, p less than 0.001. Serial values were measured in two women in whom the iCT values declined each day. Gel filtration of the iCT from two patients with the highest values suggested that some polymeric molecular species, rather than authentic CT, accounted for 90% of the circulating iCT value. No abnormalities of DBP levels were found, and no correlation with CaT, Ca+ +, or iCT was evident. The hypocalcemia of the TSS represents a reduction in both CaT and Ca+ + concentrations, which may be at least partially accounted for by the elevated iCT concentrations.

  3. Staphylococcal Infections

    MedlinePlus

    ... number of skin infections (eg, impetigo, pimples, boils). Staphylococcus aureus also causes toxin-related illnesses, including toxic shock syndrome, scalded skin syndrome, and staphylococcal-related food poisoning. In fact, ... Staphylococcus that you should be familiar with include the ...

  4. Genomics of Pathogenic Vibrio Species

    NASA Astrophysics Data System (ADS)

    Dziejman, Michelle; Yildiz, Fitnat H.

    Members of the heterotrophic bacterial family Vibrionaceae are native inhabitants of aquatic environments worldwide, constituting a diverse and abundant component of marine microbial organisms. Over 60 species of the genus Vibrio have been identified (Thompson et al., 2004) and their phenotypic heterogeneity is well documented. The ecology of the genus remains less well understood, however, despite reports that vibrios are the dominant microorganisms inhabiting the superficial water layer and colonizing the chitinous exoskeleton of zooplankton (e.g., copepods, Thompson et al., 2004). Although some species were originally isolated from seawater as free living organisms, most were isolated in association with marine life such as bivalves, fish, eels, or shrimp.

  5. Reprint of "Identification of staphylococcal species based on variations in protein sequences (mass spectrometry) and DNA sequence (sodA microarray)".

    PubMed

    Kooken, Jennifer; Fox, Karen; Fox, Alvin; Altomare, Diego; Creek, Kim; Wunschel, David; Pajares-Merino, Sara; Martínez-Ballesteros, Ilargi; Garaizar, Javier; Oyarzabal, Omar; Samadpour, Mansour

    2014-01-01

    This report is among the first using sequence variation in newly discovered protein markers for staphylococcal (or indeed any other bacterial) speciation. Variation, at the DNA sequence level, in the sodA gene (commonly used for staphylococcal speciation) provided excellent correlation. Relatedness among strains was also assessed using protein profiling using microcapillary electrophoresis and pulsed field electrophoresis. A total of 64 strains were analyzed including reference strains representing the 11 staphylococcal species most commonly isolated from man (Staphylococcus aureus and 10 coagulase negative species [CoNS]). Matrix assisted time of flight ionization/ionization mass spectrometry (MALDI TOF MS) and liquid chromatography-electrospray ionization tandem mass spectrometry (LC ESI MS/MS) were used for peptide analysis of proteins isolated from gel bands. Comparison of experimental spectra of unknowns versus spectra of peptides derived from reference strains allowed bacterial identification after MALDI TOF MS analysis. After LC-MS/MS analysis of gel bands bacterial speciation was performed by comparing experimental spectra versus virtual spectra using the software X!Tandem. Finally LC-MS/MS was performed on whole proteomes and data analysis also employing X!tandem. Aconitate hydratase and oxoglutarate dehydrogenase served as marker proteins on focused analysis after gel separation. Alternatively on full proteomics analysis elongation factor Tu generally provided the highest confidence in staphylococcal speciation.

  6. Comparative Phylogenomics of Pathogenic and Nonpathogenic Species

    PubMed Central

    Whiston, Emily; Taylor, John W.

    2015-01-01

    The Ascomycete Onygenales order embraces a diverse group of mammalian pathogens, including the yeast-forming dimorphic fungal pathogens Histoplasma capsulatum, Paracoccidioides spp. and Blastomyces dermatitidis, the dermatophytes Microsporum spp. and Trichopyton spp., the spherule-forming dimorphic fungal pathogens in the genus Coccidioides, and many nonpathogens. Although genomes for all of the aforementioned pathogenic species are available, only one nonpathogen had been sequenced. Here, we enhance comparative phylogenomics in Onygenales by adding genomes for Amauroascus mutatus, Amauroascus niger, Byssoonygena ceratinophila, and Chrysosporium queenslandicum—four nonpathogenic Onygenales species, all of which are more closely related to Coccidioides spp. than any other known Onygenales species. Phylogenomic detection of gene family expansion and contraction can provide clues to fungal function but is sensitive to taxon sampling. By adding additional nonpathogens, we show that LysM domain-containing proteins, previously thought to be expanding in some Onygenales, are contracting in the Coccidioides-Uncinocarpus clade, as are the self-nonself recognition Het loci. The denser genome sampling presented here highlights nearly 800 genes unique to Coccidiodes, which have significantly fewer known protein domains and show increased expression in the endosporulating spherule, the parasitic phase unique to Coccidioides spp. These genomes provide insight to gene family expansion/contraction and patterns of individual gene gain/loss in this diverse order—both major drivers of evolutionary change. Our results suggest that gene family expansion/contraction can lead to adaptive radiations that create taxonomic orders, while individual gene gain/loss likely plays a more significant role in branch-specific phenotypic changes that lead to adaptation for species or genera. PMID:26613950

  7. Comparative Phylogenomics of Pathogenic and Nonpathogenic Species.

    PubMed

    Whiston, Emily; Taylor, John W

    2016-02-01

    The Ascomycete Onygenales order embraces a diverse group of mammalian pathogens, including the yeast-forming dimorphic fungal pathogens Histoplasma capsulatum, Paracoccidioides spp. and Blastomyces dermatitidis, the dermatophytes Microsporum spp. and Trichopyton spp., the spherule-forming dimorphic fungal pathogens in the genus Coccidioides, and many nonpathogens. Although genomes for all of the aforementioned pathogenic species are available, only one nonpathogen had been sequenced. Here, we enhance comparative phylogenomics in Onygenales by adding genomes for Amauroascus mutatus, Amauroascus niger, Byssoonygena ceratinophila, and Chrysosporium queenslandicum--four nonpathogenic Onygenales species, all of which are more closely related to Coccidioides spp. than any other known Onygenales species. Phylogenomic detection of gene family expansion and contraction can provide clues to fungal function but is sensitive to taxon sampling. By adding additional nonpathogens, we show that LysM domain-containing proteins, previously thought to be expanding in some Onygenales, are contracting in the Coccidioides-Uncinocarpus clade, as are the self-nonself recognition Het loci. The denser genome sampling presented here highlights nearly 800 genes unique to Coccidiodes, which have significantly fewer known protein domains and show increased expression in the endosporulating spherule, the parasitic phase unique to Coccidioides spp. These genomes provide insight to gene family expansion/contraction and patterns of individual gene gain/loss in this diverse order--both major drivers of evolutionary change. Our results suggest that gene family expansion/contraction can lead to adaptive radiations that create taxonomic orders, while individual gene gain/loss likely plays a more significant role in branch-specific phenotypic changes that lead to adaptation for species or genera. PMID:26613950

  8. StaphyloBase: a specialized genomic resource for the staphylococcal research community.

    PubMed

    Heydari, Hamed; Mutha, Naresh V R; Mahmud, Mahafizul Imran; Siow, Cheuk Chuen; Wee, Wei Yee; Wong, Guat Jah; Yazdi, Amir Hessam; Ang, Mia Yang; Choo, Siew Woh

    2014-01-01

    With the advent of high-throughput sequencing technologies, many staphylococcal genomes have been sequenced. Comparative analysis of these strains will provide better understanding of their biology, phylogeny, virulence and taxonomy, which may contribute to better management of diseases caused by staphylococcal pathogens. We developed StaphyloBase with the goal of having a one-stop genomic resource platform for the scientific community to access, retrieve, download, browse, search, visualize and analyse the staphylococcal genomic data and annotations. We anticipate this resource platform will facilitate the analysis of staphylococcal genomic data, particularly in comparative analyses. StaphyloBase currently has a collection of 754 032 protein-coding sequences (CDSs), 19 258 rRNAs and 15 965 tRNAs from 292 genomes of different staphylococcal species. Information about these features is also included, such as putative functions, subcellular localizations and gene/protein sequences. Our web implementation supports diverse query types and the exploration of CDS- and RNA-type information in detail using an AJAX-based real-time search system. JBrowse has also been incorporated to allow rapid and seamless browsing of staphylococcal genomes. The Pairwise Genome Comparison tool is designed for comparative genomic analysis, for example, to reveal the relationships between two user-defined staphylococcal genomes. A newly designed Pathogenomics Profiling Tool (PathoProT) is also included in this platform to facilitate comparative pathogenomics analysis of staphylococcal strains. In conclusion, StaphyloBase offers access to a range of staphylococcal genomic resources as well as analysis tools for comparative analyses. Database URL: http://staphylococcus.um.edu.my/.

  9. Species and staphylococcal cassette chromosome mec (SCCmec) diversity among methicillin-resistant non-Staphylococcus aureus staphylococci isolated from pigs.

    PubMed

    Vanderhaeghen, Wannes; Vandendriessche, Stien; Crombé, Florence; Dispas, Marc; Denis, Olivier; Hermans, Katleen; Haesebrouck, Freddy; Butaye, Patrick

    2012-07-01

    While methicillin-resistant Staphylococcus aureus (MRSA) ST398 is known to be widespread in pig farms, few studies have investigated the species diversity and SCCmec types of methicillin-resistant non-S. aureus staphylococci (MRNAS) residing in the nose of pigs. We examined nasal swab samples of 200 pigs originating from 10 Belgian pig farms previously found positive for MRSA ST398. Suspected staphylococcal isolates were subjected to a 16S rRNA-mecA-nuc PCR. Confirmed MRNAS were genotypically identified to the species level and investigated with a SCCmec typing PCR. MRNAS (n=72) were detected on all 10 farms and were carried by 29.5% of the pigs. Seven MRNAS species were found: Staphylococcus epidermidis (38.9%), Staphylococcus sciuri (18.1%), Staphylococcus pasteuri (18.1%), Staphylococcus rostri (12.5%), Staphylococcus warneri (8.3%), Staphylococcus haemolyticus (2.7%) and Staphylococcus hominis (1.4%). SCCmec cassettes were of type IVa (29.2%), type IVc (25%), type III (22.2%), type V (5.6%) or could not be assigned to any of the known types (NT types) (18.1%). Five distinct NT types were found. The predominance of methicillin-resistant S. epidermidis (MRSE) in our samples is remarkable, as MRSE is mainly associated with humans. The finding of three different SCCmec elements (IVa, V, NT type 1) in MRNAS that also prevail or predominate in MRSA ST398 shows that MRNAS might be an important SCCmec reservoir for MRSA in pigs. Yet, the occurrence of multiple other SCCmec types illustrates that further studies are required to understand the presence and spread of SCCmec in methicillin-resistant staphylococci from animals.

  10. Molecular Diagnosis of Pathogenic Sporothrix Species

    PubMed Central

    Rodrigues, Anderson Messias; de Hoog, G. Sybren; de Camargo, Zoilo Pires

    2015-01-01

    Background Sporotrichosis is a chronic (sub)cutaneous infection caused by thermodimorphic fungi in the order, Ophiostomatales. These fungi are characterized by major differences in routes of transmission, host predilections, species virulence, and susceptibilities to antifungals. Sporothrix species emerge in the form of outbreaks. Large zoonoses and sapronoses are ongoing in Brazil and China, respectively. Current diagnostic methods based on morphology and physiology are inaccurate due to closely related phenotypes with overlapping components between pathogenic and non-pathogenic Sporothrix. There is a critical need for new diagnostic tools that are specific, sensitive, and cost-effective. Methodology We developed a panel of novel markers, based on calmodulin (CAL) gene sequences, for the large-scale diagnosis and epidemiology of clinically relevant members of the Sporothrix genus, and its relative, Ophiostoma. We identified specific PCR-based markers for S. brasiliensis, S. schenckii, S. globosa, S. mexicana, S. pallida, and O. stenoceras. We employed a murine model of disseminated sporotrichosis to optimize a PCR assay for detecting Sporothrix in clinical specimens. Results Primer-BLAST searches revealed candidate sequences that were conserved within a single species. Species-specific primers showed no significant homology with human, mouse, or microorganisms outside the Sporothrix genus. The detection limit was 10–100 fg of DNA in a single round of PCR for identifying S. brasiliensis, S. schenckii, S. globosa, S. mexicana, and S. pallida. A simple, direct PCR assay, with conidia as a source of DNA, was effective for rapid, low-cost genotyping. Samples from a murine model of disseminated sporotrichosis confirmed the feasibility of detecting S. brasiliensis and S. schenckii DNA in spleen, liver, lungs, heart, brain, kidney, tail, and feces of infected animals. Conclusions This PCR-based method could successfully detect and identify a single species in samples

  11. Staphylococcus argensis sp. nov., a novel staphylococcal species isolated from an aquatic environment.

    PubMed

    Heß, Stefanie; Gallert, Claudia

    2015-08-01

    A staphylocoagulase-negative, novobiocin-susceptible strain (M4S-6T) of a species of the genus Staphylococcus was isolated from the river Argen in Southern Germany. It was assigned to the genus Staphylococcus due to the presence of the fatty acids, ai-C15 : 0, i-C15 : 0, i-C17 : 0, ai-C17 : 0, and of menaquinone (MK-7) in the cytoplasmic membrane, which are typical of coagulase-negative staphylococci. The polar lipid profile consisted of phosphatidylglycerol, diphosphatidylglycerol, an unknown phospholipid and an unknown glycolipid. Although the 16S gene sequence of strain M4S-6T revealed a 98% similarity with its closest relative, Staphylococcus pettenkoferi, it could be distinguished by several phenotypical and physiological markers. In contrast to S. pettenkoferi, M4S-6T was ornithine decarboxylase-positive, urease-negative and could use formiate and l-histidine as carbon-sources; nitrate was not reduced. Whereas S. pettenkoferi could grow with d(-)-mannitol, d-sorbitol, gluconic acid, l-proline, carboxymethylcellulose and lignosulfonate, M4S-6T was not able to grow with these substances. The results of 16S rRNA gene sequence analysis and of phenotypic testing indicated that M4S-6T was a representative of a novel species for which the name Staphylococcus argensis sp. nov., is proposed with the type strain M4S-6T (DSM 29875T = CIP 110904T).

  12. Emergence and accumulation of novel pathogens suppress an invasive species.

    PubMed

    Stricker, Kerry Bohl; Harmon, Philip F; Goss, Erica M; Clay, Keith; Luke Flory, S

    2016-04-01

    Emerging pathogens are a growing threat to human health, agriculture and the diversity of ecological communities but may also help control problematic species. Here we investigated the diversity, distribution and consequences of emerging fungal pathogens infecting an aggressive invasive grass that is rapidly colonising habitats throughout the eastern USA. We document the recent emergence and accumulation over time of diverse pathogens that are members of a single fungal genus and represent multiple, recently described or undescribed species. We also show that experimental suppression of these pathogens increased host performance in the field, demonstrating the negative effects of emerging pathogens on invasive plants. Our results suggest that invasive species can facilitate pathogen emergence and amplification, raising concerns about movement of pathogens among agricultural, horticultural, and wild grasses. However, one possible benefit of pathogen accumulation is suppression of aggressive invaders over the long term, potentially abating their negative impacts on native communities.

  13. Comparison of phenotypic and genotypic methods for the species identification of coagulase-negative staphylococcal isolates from bovine intramammary infections

    PubMed Central

    Park, Joo Youn; Fox, Lawrence K.; Seo, Keun Seok; McGuire, Mark A.; Park, Yong Ho; Rurangirwa, Fred R.; Sischo, William M.; Bohach, Gregory A.

    2013-01-01

    Coagulase-negative staphylococci (CNS) are the most frequently isolated pathogens from cows with intramammary infection (IMI). Although API STAPH ID 20, a commercially available identification system, and PCR-restriction fragment length polymorphism (PCR-RFLP) of the gap gene (gap PCR-RFLP) have been successfully applied for the identification of CNS isolates from human specimens, their accuracy in the identification of veterinary isolates has not been fully established. In this study, we identified 263 CNS isolates from bovine IMI at species level by partial 16S rRNA gene sequence analysis as the definitive test. Species identification obtained using partial 16S rRNA gene sequence analysis was compared to results from the API STAPH ID 20 and gap PCR-RFLP analysis. Eleven different CNS species were identified by partial 16S rRNA gene sequence analysis. Only 76.0 % (200 / 263) of the species identification results obtained by API STAPH ID 20 matched those obtained by partial 16S rRNA gene sequence analysis, whereas 97.0 % (255 / 263) of the species identification results obtained by the gap PCR-RFLP analysis matched those obtained by partial 16S rRNA gene sequence analysis. The gap PCR-RFLP analysis could be a useful and reliable alternative method for the species identification of CNS isolates from bovine IMI and appears to be a more accurate method of species identification than the API STAPH ID 20 system. PMID:20667671

  14. Staphylococcal Enterotoxins

    PubMed Central

    Pinchuk, Irina V.; Beswick, Ellen J.; Reyes, Victor E.

    2010-01-01

    Staphylococcus aureus (S. aureus) is a Gram positive bacterium that is carried by about one third of the general population and is responsible for common and serious diseases. These diseases include food poisoning and toxic shock syndrome, which are caused by exotoxins produced by S. aureus. Of the more than 20 Staphylococcal enterotoxins, SEA and SEB are the best characterized and are also regarded as superantigens because of their ability to bind to class II MHC molecules on antigen presenting cells and stimulate large populations of T cells that share variable regions on the β chain of the T cell receptor. The result of this massive T cell activation is a cytokine bolus leading to an acute toxic shock. These proteins are highly resistant to denaturation, which allows them to remain intact in contaminated food and trigger disease outbreaks. A recognized problem is the emergence of multi-drug resistant strains of S. aureus and these are a concern in the clinical setting as they are a common cause of antibiotic-associated diarrhea in hospitalized patients. In this review, we provide an overview of the current understanding of these proteins. PMID:22069679

  15. Cryptosporidium species a "new" human pathogen.

    PubMed Central

    Casemore, D P; Sands, R L; Curry, A

    1985-01-01

    Publications describing aspects of the coccidian protozoan parasite Cryptosporidium, increased greatly during 1983 and 1984 as a result of not only increasing veterinary interest but also in the role of the parasite in the newly recognised acquired immune deficiency syndrome (AIDS). The reports reflected widespread collaboration, not only between clinicians, microbiologists, and histopathologists, but also between veterinary and human health care workers. Cryptosporidium was first described in mice in 1907 and subsequently in various other species; it was not described in man until 1976. Several likely putative species have been described, but there is probably little host specificity. Experimental and clinical studies have greatly increased the knowledge about the organism's biology. The parasite undergoes its complete life cycle within the intestine, although it may occasionally occur in other sites. The main symptom produced is a non-inflammatory diarrhoea, which, in patients with AIDS and children in Third World countries, may be life threatening: even in immunocompetent subjects this symptom is usually protracted. Attempts to find effective chemotherapeutic agents have been unsuccessful. Epidemiologically the infection was thought to be zoonotic in origin, but there is increasing evidence of person to person transmission. Diagnosis has depended upon histological examination, but simple methods of detection have now been described: more invasive methods need no longer be used. The parasite, which is found more commonly in children, occurs in about 2% of faecal specimens examined and seems to be closely associated with production of symptoms. A serological response has been shown. Much remains to be learned about its epidemiology and pathogenic mechanisms, while the expected increase in incidence of AIDS makes an effective form of treatment essential. Images PMID:3908490

  16. Staphylococcal peptidoglycans induce arthritis

    PubMed Central

    Liu, Zai-Qing; Deng, Guo-Min; Foster, Simon; Tarkowski, Andrej

    2001-01-01

    Staphylococcus aureus is one of the most important pathogens in septic arthritis. To analyse the arthritogenic properties of staphylococcal peptidoglycan (PGN), highly purified PGN from S. aureus was intra-articularly injected into murine joints. The results demonstrate that PGN will trigger arthritis in a dose-dependent manner. A single injection of this compound leads to massive infiltration of predominantly macrophages and polymorphonuclear cells with occasional signs of cartilage and/or bone destruction, lasting for at least 14 days. Further studies showed that this condition is mediated by the combined impact of acquired and innate immune systems. Our results indicate that PGN exerts a central role in joint inflammation triggered by S. aureus. PMID:11714392

  17. Application of the antibiotic batumin for accurate and rapid identification of staphylococcal small colony variants

    PubMed Central

    2012-01-01

    Background Staphylococcus aureus is a major human pathogen causing significant morbidity and mortality. The S. aureus colonies in osteomyelitis, in patients with cystic fibrosis and patients with endoprosthesis rejection frequently have an atypical morphology, i.e. staphylococcal small-colony variants, which form a naturally occurring subpopulation of clinically important staphylococci. Identification of these small colony variants is difficult, because of the loss of typical phenotypic characteristics of these variants. We wanted to improve and simplify the diagnosis of staphylococcal infection using a diagnostic preparation, consisting of 5 μg batumin paper disks. Batumin possesses a unique selective activity against all studied Staphylococcus spp., whereas all other species tested thus far are batumin resistant. We assessed the efficacy of the batumin diagnostic preparation to identify staphylococcal small colony variants, isolated from osteomyelitis patients. Findings With the batumin diagnostic preparation, all 30 tested staphylococcal small-colony variants had a growth inhibition zone around the disk of minimum 25 mm, accordant with the inhibition zones of the parent strains, isolated from the same patients. Conclusions The batumin diagnostic preparation correctly identified the small-colony variants of S. aureus, S. haemolyticus and S. epidermidis as belonging to the genus Staphylococcus, which differ profoundly from parental strains and are difficult to identify with standard methods. Identification of staphylococcal small-colony variants with the batumin diagnostic preparation is technically simple and can facilitate practical laboratory work. PMID:22828414

  18. Usefulness of Multiplex Real-Time PCR for Simultaneous Pathogen Detection and Resistance Profiling of Staphylococcal Bacteremia

    PubMed Central

    Chung, Yousun; Kim, Taek Soo; Min, Young Gi; Hong, Yun Ji; Park, Jeong Su; Hwang, Sang Mee; Song, Kyoung-Ho; Kim, Eu Suk; Kim, Hong Bin; Song, Junghan; Kim, Eui-Chong

    2016-01-01

    Staphylococci are the leading cause of nosocomial blood stream infections. Fast and accurate identification of staphylococci and confirmation of their methicillin resistance are crucial for immediate treatment with effective antibiotics. A multiplex real-time PCR assay that targets mecA, femA specific for S. aureus, femA specific for S. epidermidis, 16S rRNA for universal bacteria, and 16S rRNA specific for staphylococci was developed and evaluated with 290 clinical blood culture samples containing Gram-positive cocci in clusters (GPCC). For the 262 blood cultures identified to the species level with the MicroScan WalkAway system (Siemens Healthcare Diagnostics, USA), the direct real-time PCR assay of positive blood cultures showed very good agreement for the categorization of staphylococci into methicillin-resistant S. aureus (MRSA), methicillin-susceptible S. aureus (MSSA), methicillin-resistant S. epidermidis (MRSE), methicillin-susceptible S. epidermidis (MSSE), methicillin-resistant non-S. epidermidis CoNS (MRCoNS), and methicillin-susceptible non-S. epidermidis CoNS (MSCoNS) (κ = 0.9313). The direct multiplex real-time PCR assay of positive blood cultures containing GPCC can provide essential information at the critical point of infection with a turnaround time of no more than 4 h. Further studies should evaluate the clinical outcome of using this rapid real-time PCR assay in glycopeptide antibiotic therapy in clinical settings. PMID:27403436

  19. Usefulness of Multiplex Real-Time PCR for Simultaneous Pathogen Detection and Resistance Profiling of Staphylococcal Bacteremia.

    PubMed

    Chung, Yousun; Kim, Taek Soo; Min, Young Gi; Hong, Yun Ji; Park, Jeong Su; Hwang, Sang Mee; Song, Kyoung-Ho; Kim, Eu Suk; Park, Kyoung Un; Kim, Hong Bin; Song, Junghan; Kim, Eui-Chong

    2016-01-01

    Staphylococci are the leading cause of nosocomial blood stream infections. Fast and accurate identification of staphylococci and confirmation of their methicillin resistance are crucial for immediate treatment with effective antibiotics. A multiplex real-time PCR assay that targets mecA, femA specific for S. aureus, femA specific for S. epidermidis, 16S rRNA for universal bacteria, and 16S rRNA specific for staphylococci was developed and evaluated with 290 clinical blood culture samples containing Gram-positive cocci in clusters (GPCC). For the 262 blood cultures identified to the species level with the MicroScan WalkAway system (Siemens Healthcare Diagnostics, USA), the direct real-time PCR assay of positive blood cultures showed very good agreement for the categorization of staphylococci into methicillin-resistant S. aureus (MRSA), methicillin-susceptible S. aureus (MSSA), methicillin-resistant S. epidermidis (MRSE), methicillin-susceptible S. epidermidis (MSSE), methicillin-resistant non-S. epidermidis CoNS (MRCoNS), and methicillin-susceptible non-S. epidermidis CoNS (MSCoNS) (κ = 0.9313). The direct multiplex real-time PCR assay of positive blood cultures containing GPCC can provide essential information at the critical point of infection with a turnaround time of no more than 4 h. Further studies should evaluate the clinical outcome of using this rapid real-time PCR assay in glycopeptide antibiotic therapy in clinical settings. PMID:27403436

  20. Genomic Basis of Plant Pathogen Suppression by Biocontrol Pseudomonas Species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Various plant commensal bacterial species, which naturally colonize the plant rhizosphere, are able to suppress fungal, bacterial, viral and even insect plant pathogens. These biocontrol activities are elicited primarily through the production of secreted exoenzymes and secondary metabolites that ma...

  1. Phytotoxins produced by plant pathogenic Streptomyces species.

    PubMed

    Bignell, D R D; Fyans, J K; Cheng, Z

    2014-02-01

    Streptomyces is a large genus consisting of soil-dwelling, filamentous bacteria that are best known for their capability of producing a vast array of medically and agriculturally useful secondary metabolites. In addition, a small number of Streptomyces spp. are capable of colonizing and infecting the underground portions of living plants and causing economically important crop diseases such as potato common scab (CS). Research into the mechanisms of Streptomyces plant pathogenicity has led to the identification and characterization of several phytotoxic secondary metabolites that are known or suspected of contributing to diseases in various plants. The best characterized are the thaxtomin phytotoxins, which play a critical role in the development of CS, acid scab and soil rot of sweet potato. In addition, the best-characterized CS-causing pathogen, Streptomyces scabies, produces a molecule that is predicted to resemble the Pseudomonas syringae coronatine phytotoxin and which contributes to seedling disease symptom development. Other Streptomyces phytotoxic secondary metabolites that have been identified include concanamycins, FD-891 and borrelidin. Furthermore, there is evidence that additional, unknown metabolites may participate in Streptomyces plant pathogenicity. Such revelations have implications for the rational development of better management procedures for controlling CS and other Streptomyces plant diseases.

  2. Phytotoxins produced by plant pathogenic Streptomyces species.

    PubMed

    Bignell, D R D; Fyans, J K; Cheng, Z

    2014-02-01

    Streptomyces is a large genus consisting of soil-dwelling, filamentous bacteria that are best known for their capability of producing a vast array of medically and agriculturally useful secondary metabolites. In addition, a small number of Streptomyces spp. are capable of colonizing and infecting the underground portions of living plants and causing economically important crop diseases such as potato common scab (CS). Research into the mechanisms of Streptomyces plant pathogenicity has led to the identification and characterization of several phytotoxic secondary metabolites that are known or suspected of contributing to diseases in various plants. The best characterized are the thaxtomin phytotoxins, which play a critical role in the development of CS, acid scab and soil rot of sweet potato. In addition, the best-characterized CS-causing pathogen, Streptomyces scabies, produces a molecule that is predicted to resemble the Pseudomonas syringae coronatine phytotoxin and which contributes to seedling disease symptom development. Other Streptomyces phytotoxic secondary metabolites that have been identified include concanamycins, FD-891 and borrelidin. Furthermore, there is evidence that additional, unknown metabolites may participate in Streptomyces plant pathogenicity. Such revelations have implications for the rational development of better management procedures for controlling CS and other Streptomyces plant diseases. PMID:24131731

  3. Two Phages, phiIPLA-RODI and phiIPLA-C1C, Lyse Mono- and Dual-Species Staphylococcal Biofilms

    PubMed Central

    Gutiérrez, Diana; Vandenheuvel, Dieter; Martínez, Beatriz; Rodríguez, Ana; Lavigne, Rob

    2015-01-01

    Phage therapy is a promising option for fighting against staphylococcal infections. Two lytic phages, vB_SauM_phiIPLA-RODI (phiIPLA-RODI) and vB_SepM_phiIPLA-C1C (phiIPLA-C1C), belonging to the Myoviridae family and exhibiting wide host ranges, were characterized in this study. The complete genome sequences comprised 142,348 bp and 140,961 bp and contained 213 and 203 open reading frames, respectively. The gene organization was typical of Spounavirinae members, with long direct terminal repeats (LTRs), genes grouped into modules not clearly separated from each other, and several group I introns. In addition, four genes encoding tRNAs were identified in phiIPLA-RODI. Comparative DNA sequence analysis showed high similarities with two phages, GH15 and 676Z, belonging to the Twort-like virus genus (nucleotide identities of >84%); for phiIPLA-C1C, a high similarity with phage phiIBB-SEP1 was observed (identity of 80%). Challenge assays of phages phiIPLA-RODI and phiIPLA-C1C against planktonic staphylococcal cells confirmed their lytic ability, as they were able to remove 5 log units in 8 h. Exposure of biofilms to phages phiIPLA-RODI and phiIPLA-C1C reduced the amount of adhered bacteria to about 2 log units in both monospecies and dual-species biofilms, but phiIPLA-RODI turned out to be as effective as the mixture of both phages. Moreover, the frequencies of bacteriophage-insensitive mutants (BIMs) of Staphylococcus aureus and S. epidermidis with resistance to phiIPLA-RODI and phiIPLA-C1C were low, at 4.05 × 10−7 ± 2.34 × 10−9 and 1.1 × 10−7 ± 2.08 × 10−9, respectively. Overall, a generally reduced fitness in the absence of phages was observed for BIMs, which showed a restored phage-sensitive phenotype in a few generations. These results confirm that lytic bacteriophages can be efficient biofilm-disrupting agents, supporting their potential as antimicrobials against staphylococcal infections. PMID:25746992

  4. Two Phages, phiIPLA-RODI and phiIPLA-C1C, Lyse Mono- and Dual-Species Staphylococcal Biofilms.

    PubMed

    Gutiérrez, Diana; Vandenheuvel, Dieter; Martínez, Beatriz; Rodríguez, Ana; Lavigne, Rob; García, Pilar

    2015-05-15

    Phage therapy is a promising option for fighting against staphylococcal infections. Two lytic phages, vB_SauM_phiIPLA-RODI (phiIPLA-RODI) and vB_SepM_phiIPLA-C1C (phiIPLA-C1C), belonging to the Myoviridae family and exhibiting wide host ranges, were characterized in this study. The complete genome sequences comprised 142,348 bp and 140,961 bp and contained 213 and 203 open reading frames, respectively. The gene organization was typical of Spounavirinae members, with long direct terminal repeats (LTRs), genes grouped into modules not clearly separated from each other, and several group I introns. In addition, four genes encoding tRNAs were identified in phiIPLA-RODI. Comparative DNA sequence analysis showed high similarities with two phages, GH15 and 676Z, belonging to the Twort-like virus genus (nucleotide identities of >84%); for phiIPLA-C1C, a high similarity with phage phiIBB-SEP1 was observed (identity of 80%). Challenge assays of phages phiIPLA-RODI and phiIPLA-C1C against planktonic staphylococcal cells confirmed their lytic ability, as they were able to remove 5 log units in 8 h. Exposure of biofilms to phages phiIPLA-RODI and phiIPLA-C1C reduced the amount of adhered bacteria to about 2 log units in both monospecies and dual-species biofilms, but phiIPLA-RODI turned out to be as effective as the mixture of both phages. Moreover, the frequencies of bacteriophage-insensitive mutants (BIMs) of Staphylococcus aureus and S. epidermidis with resistance to phiIPLA-RODI and phiIPLA-C1C were low, at 4.05 × 10(-7) ± 2.34 × 10(-9) and 1.1 × 10(-7) ± 2.08 × 10(-9), respectively. Overall, a generally reduced fitness in the absence of phages was observed for BIMs, which showed a restored phage-sensitive phenotype in a few generations. These results confirm that lytic bacteriophages can be efficient biofilm-disrupting agents, supporting their potential as antimicrobials against staphylococcal infections. PMID:25746992

  5. Molecular characterization of femA from Staphylococcus hominis and Staphylococcus saprophyticus, and femA-based discrimination of staphylococcal species.

    PubMed

    Vannuffel, P; Heusterspreute, M; Bouyer, M; Vandercam, B; Philippe, M; Gala, J L

    1999-03-01

    The femA gene encodes a protein precursor which plays a role in peptidoglycan biosynthesis in Staphylococcus aureus and is also considered as a factor influencing the level of methicillin resistance. A femA homologous gene was recently characterized in S. epidermidis, entailing the possibility of femA phylogenetic conservation in staphylococcal species. Accordingly, we assessed the presence of femA homologous genes in S. hominis and S. saprophyticus. Strategy for identification relied upon alignment of S. aureus and D. epidermidis femA sequences and upon identification of potentially conserved regions. Amplifications of portions of the femA genes were performed under permissive annealing conditions, by using several sets of primers designed to match the consensus regions. DNA sequencing of overlapping PCR fragments led to the characterization of the entire femA genes of S. hominis and S. saprophyticus, and provided more precise information on the femA start codon for all five species. The genomic organization of all these femA genes appeared highly conserved, with alternance of homologous and variable regions. On this basis, a consensus sequence of the femA gene was defined and interspecies variations were exploited to design strategies for staphylococci species-specific identification, including multiplex PCR amplification and a reverse hybridization assay.

  6. Genetic islands in pome fruit pathogenic and non-pathogenic Erwinia species and related plasmids

    PubMed Central

    Llop, Pablo

    2015-01-01

    New pathogenic bacteria belonging to the genus Erwinia associated with pome fruit trees (Erwinia, E. piriflorinigrans, E. uzenensis) have been increasingly described in the last years, and comparative analyses have found that all these species share several genetic characteristics. Studies at different level (whole genome comparison, virulence genes, plasmid content, etc.) show a high intraspecies homogeneity (i.e., among E. amylovora strains) and also abundant similarities appear between the different Erwinia species: presence of plasmids of similar size in the pathogenic species; high similarity in several genes associated with exopolysaccharide production and hence, with virulence, as well as in some other genes, in the chromosomes. Many genetic similarities have been observed also among some of the plasmids (and genomes) from the pathogenic species and E. tasmaniensis or E. billingiae, two epiphytic species on the same hosts. The amount of genetic material shared in this genus varies from individual genes to clusters, genomic islands and genetic material that even may constitute a whole plasmid. Recent research on evolution of erwinias point out the horizontal transfer acquisition of some genomic islands that were subsequently lost in some species and several pathogenic traits that are still present. How this common material has been obtained and is efficiently maintained in different species belonging to the same genus sharing a common ecological niche provides an idea of the origin and evolution of the pathogenic Erwinia and the interaction with non-pathogenic species present in the same niche, and the role of the genes that are conserved in all of them. PMID:26379649

  7. Extracellular proteolytic enzymes produced by human pathogenic vibrio species

    PubMed Central

    Miyoshi, Shin-ichi

    2013-01-01

    Bacteria in the genus Vibrio produce extracellular proteolytic enzymes to obtain nutrients via digestion of various protein substrates. However, the enzymes secreted by human pathogenic species have been documented to modulate the bacterial virulence. Several species including Vibrio cholerae and V. vulnificus are known to produce thermolysin-like metalloproteases termed vibriolysin. The vibriolysin from V. vulnificus, a causative agent of serious systemic infection, is a major toxic factor eliciting the secondary skin damage characterized by formation of the hemorrhagic brae. The vibriolysin from intestinal pathogens may play indirect roles in pathogenicity because it can activate protein toxins and hemagglutinin by the limited proteolysis and can affect the bacterial attachment to or detachment from the intestinal surface by degradation of the mucus layer. Two species causing wound infections, V. alginolyticus and V. parahaemolyticus, produce another metalloproteases so-called collagenases. Although the detailed pathological roles have not been studied, the collagenase is potent to accelerate the bacterial dissemination through digestion of the protein components of the extracellular matrix. Some species produce cymotrypsin-like serine proteases, which may also affect the bacterial virulence potential. The intestinal pathogens produce sufficient amounts of the metalloprotease at the small intestinal temperature; however, the metalloprotease production by extra-intestinal pathogens is much higher around the body surface temperature. On the other hand, the serine protease is expressed only in the absence of the metalloprotease. PMID:24302921

  8. A New Family of Secreted Toxins in Pathogenic Neisseria Species

    PubMed Central

    Jamet, Anne; Jousset, Agnès B.; Euphrasie, Daniel; Mukorako, Paulette; Boucharlat, Alix; Ducousso, Alexia; Charbit, Alain; Nassif, Xavier

    2015-01-01

    The genus Neisseria includes both commensal and pathogenic species which are genetically closely related. However, only meningococcus and gonococcus are important human pathogens. Very few toxins are known to be secreted by pathogenic Neisseria species. Recently, toxins secreted via type V secretion system and belonging to the widespread family of contact-dependent inhibition (CDI) toxins have been described in numerous species including meningococcus. In this study, we analyzed loci containing the maf genes in N. meningitidis and N. gonorrhoeae and proposed a novel uniform nomenclature for maf genomic islands (MGIs). We demonstrated that mafB genes encode secreted polymorphic toxins and that genes immediately downstream of mafB encode a specific immunity protein (MafI). We focused on a MafB toxin found in meningococcal strain NEM8013 and characterized its EndoU ribonuclease activity. maf genes represent 2% of the genome of pathogenic Neisseria, and are virtually absent from non-pathogenic species, thus arguing for an important biological role. Indeed, we showed that overexpression of one of the four MafB toxins of strain NEM8013 provides an advantage in competition assays, suggesting a role of maf loci in niche adaptation. PMID:25569427

  9. A new family of secreted toxins in pathogenic Neisseria species.

    PubMed

    Jamet, Anne; Jousset, Agnès B; Euphrasie, Daniel; Mukorako, Paulette; Boucharlat, Alix; Ducousso, Alexia; Charbit, Alain; Nassif, Xavier

    2015-01-01

    The genus Neisseria includes both commensal and pathogenic species which are genetically closely related. However, only meningococcus and gonococcus are important human pathogens. Very few toxins are known to be secreted by pathogenic Neisseria species. Recently, toxins secreted via type V secretion system and belonging to the widespread family of contact-dependent inhibition (CDI) toxins have been described in numerous species including meningococcus. In this study, we analyzed loci containing the maf genes in N. meningitidis and N. gonorrhoeae and proposed a novel uniform nomenclature for maf genomic islands (MGIs). We demonstrated that mafB genes encode secreted polymorphic toxins and that genes immediately downstream of mafB encode a specific immunity protein (MafI). We focused on a MafB toxin found in meningococcal strain NEM8013 and characterized its EndoU ribonuclease activity. maf genes represent 2% of the genome of pathogenic Neisseria, and are virtually absent from non-pathogenic species, thus arguing for an important biological role. Indeed, we showed that overexpression of one of the four MafB toxins of strain NEM8013 provides an advantage in competition assays, suggesting a role of maf loci in niche adaptation.

  10. Distribution of Plasmids in Distinct Leptospira Pathogenic Species.

    PubMed

    Wang, Yanzhuo; Zhuang, Xuran; Zhong, Yi; Zhang, Cuicai; Zhang, Yan; Zeng, Lingbing; Zhu, Yongzhang; He, Ping; Dong, Ke; Pal, Utpal; Guo, Xiaokui; Qin, Jinhong

    2015-11-01

    Leptospirosis, caused by pathogenic Leptospira, is a worldwide zoonotic infection. The genus Leptospira includes at least 21 species clustered into three groups--pathogens, non-pathogens, and intermediates--based on 16S rRNA phylogeny. Research on Leptospira is difficult due to slow growth and poor transformability of the pathogens. Recent identification of extrachromosomal elements besides the two chromosomes in L. interrogans has provided new insight into genome complexity of the genus Leptospira. The large size, low copy number, and high similarity of the sequence of these extrachromosomal elements with the chromosomes present challenges in isolating and detecting them without careful genome assembly. In this study, two extrachromosomal elements were identified in L. borgpetersenii serovar Ballum strain 56604 through whole genome assembly combined with S1 nuclease digestion following pulsed-field gel electrophoresis (S1-PFGE) analysis. Further, extrachromosomal elements in additional 15 Chinese epidemic strains of Leptospira, comprising L. borgpetersenii, L. weilii, and L. interrogans, were successfully separated and identified, independent of genome sequence data. Southern blot hybridization with extrachromosomal element-specific probes, designated as lcp1, lcp2 and lcp3-rep, further confirmed their occurrences as extrachromosomal elements. In total, 24 plasmids were detected in 13 out of 15 tested strains, among which 11 can hybridize with the lcp1-rep probe and 11 with the lcp2-rep probe, whereas two can hybridize with the lcp3-rep probe. None of them are likely to be species-specific. Blastp search of the lcp1, lcp2, and lcp3-rep genes with a nonredundant protein database of Leptospira species genomes showed that their homologous sequences are widely distributed among clades of pathogens but not non-pathogens or intermediates. These results suggest that the plasmids are widely distributed in Leptospira species, and further elucidation of their biological

  11. Distribution of Plasmids in Distinct Leptospira Pathogenic Species.

    PubMed

    Wang, Yanzhuo; Zhuang, Xuran; Zhong, Yi; Zhang, Cuicai; Zhang, Yan; Zeng, Lingbing; Zhu, Yongzhang; He, Ping; Dong, Ke; Pal, Utpal; Guo, Xiaokui; Qin, Jinhong

    2015-11-01

    Leptospirosis, caused by pathogenic Leptospira, is a worldwide zoonotic infection. The genus Leptospira includes at least 21 species clustered into three groups--pathogens, non-pathogens, and intermediates--based on 16S rRNA phylogeny. Research on Leptospira is difficult due to slow growth and poor transformability of the pathogens. Recent identification of extrachromosomal elements besides the two chromosomes in L. interrogans has provided new insight into genome complexity of the genus Leptospira. The large size, low copy number, and high similarity of the sequence of these extrachromosomal elements with the chromosomes present challenges in isolating and detecting them without careful genome assembly. In this study, two extrachromosomal elements were identified in L. borgpetersenii serovar Ballum strain 56604 through whole genome assembly combined with S1 nuclease digestion following pulsed-field gel electrophoresis (S1-PFGE) analysis. Further, extrachromosomal elements in additional 15 Chinese epidemic strains of Leptospira, comprising L. borgpetersenii, L. weilii, and L. interrogans, were successfully separated and identified, independent of genome sequence data. Southern blot hybridization with extrachromosomal element-specific probes, designated as lcp1, lcp2 and lcp3-rep, further confirmed their occurrences as extrachromosomal elements. In total, 24 plasmids were detected in 13 out of 15 tested strains, among which 11 can hybridize with the lcp1-rep probe and 11 with the lcp2-rep probe, whereas two can hybridize with the lcp3-rep probe. None of them are likely to be species-specific. Blastp search of the lcp1, lcp2, and lcp3-rep genes with a nonredundant protein database of Leptospira species genomes showed that their homologous sequences are widely distributed among clades of pathogens but not non-pathogens or intermediates. These results suggest that the plasmids are widely distributed in Leptospira species, and further elucidation of their biological

  12. Cutaneous bacterial species from Lithobates catesbeianus can inhibit pathogenic dermatophytes.

    PubMed

    Lauer, Antje; Hernandez, Trang

    2015-04-01

    Antibiotics are being successfully used to fight many infectious diseases caused by pathogenic microorganisms. However, new infectious diseases are continuously being identified, and some known pathogens are becoming resistant against known antibiotics. Furthermore, many antifungals are causing serious side effects in long-term treatments of patients, and many skin infections caused by dermatophytes are difficult to cure. The beneficial roles of resident cutaneous microbiota to inhibit pathogenic microorganisms have been shown for many vertebrate species. Microbial symbionts on the amphibian skin for example can be a source of powerful antimicrobial metabolites that can protect amphibians against diseases, such as chytridiomycosis, caused by a fungal pathogen. In this research, we investigated whether cutaneous bacterial species isolated from Lithobates catesbeianus (North American bullfrog), an invasive amphibian species that is resistant to chytridiomycosis, produce secondary metabolites that can be used to inhibit the growth of three species of dermatophytes (Microsporum gypseum, Epidermophyton floccosum, and Trichophyton mentagrophytes) which are known to cause topical or subdermal skin infections in humans. Strongly anti-dermatophyte bacterial species that belonged to the Bacillaceae, Streptomycetaceae, Pseudomonadaceae, Xanthomonadaceae, Aeromonadaceae, and Enterobacteriaceae were identified. This research has provided evidence of the presence of cutaneous anti-dermatophyte bacteria from L. catesbeianus which might provide a basis for health care providers to experiment with new antifungals in the future. PMID:25431089

  13. Reactive oxygen species, essential molecules, during plant-pathogen interactions.

    PubMed

    Camejo, Daymi; Guzmán-Cedeño, Ángel; Moreno, Alexander

    2016-06-01

    Reactive oxygen species (ROS) are continually generated as a consequence of the normal metabolism in aerobic organisms. Accumulation and release of ROS into cell take place in response to a wide variety of adverse environmental conditions including salt, temperature, cold stresses and pathogen attack, among others. In plants, peroxidases class III, NADPH oxidase (NOX) locates in cell wall and plasma membrane, respectively, may be mainly enzymatic systems involving ROS generation. It is well documented that ROS play a dual role into cells, acting as important signal transduction molecules and as toxic molecules with strong oxidant power, however some aspects related to its function during plant-pathogen interactions remain unclear. This review focuses on the principal enzymatic systems involving ROS generation addressing the role of ROS as signal molecules during plant-pathogen interactions. We described how the chloroplasts, mitochondria and peroxisomes perceive the external stimuli as pathogen invasion, and trigger resistance response using ROS as signal molecule.

  14. Comparative functional genomics of plant pathogenic Fusarium species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium species are among the most economically important group of plant pathogenic fungi. Comparison of the four currently available Fusarium genome sequences allows an unsurpassed and unprecedented ability to predict genes, determine synteny and define regulatory sequences for genes in phytopatho...

  15. Are Reactive Oxygen Species Always Detrimental to Pathogens?

    PubMed Central

    Bozza, Marcelo T.

    2014-01-01

    Abstract Reactive oxygen species (ROS) are deadly weapons used by phagocytes and other cell types, such as lung epithelial cells, against pathogens. ROS can kill pathogens directly by causing oxidative damage to biocompounds or indirectly by stimulating pathogen elimination by various nonoxidative mechanisms, including pattern recognition receptors signaling, autophagy, neutrophil extracellular trap formation, and T-lymphocyte responses. Thus, one should expect that the inhibition of ROS production promote infection. Increasing evidences support that in certain particular infections, antioxidants decrease and prooxidants increase pathogen burden. In this study, we review the classic infections that are controlled by ROS and the cases in which ROS appear as promoters of infection, challenging the paradigm. We discuss the possible mechanisms by which ROS could promote particular infections. These mechanisms are still not completely clear but include the metabolic effects of ROS on pathogen physiology, ROS-induced damage to the immune system, and ROS-induced activation of immune defense mechanisms that are subsequently hijacked by particular pathogens to act against more effective microbicidal mechanisms of the immune system. The effective use of antioxidants as therapeutic agents against certain infections is a realistic possibility that is beginning to be applied against viruses. Antioxid. Redox Signal. 20, 1000–1037. PMID:23992156

  16. Novel organisms: comparing invasive species, GMOs, and emerging pathogens.

    PubMed

    Jeschke, Jonathan M; Keesing, Felicia; Ostfeld, Richard S

    2013-09-01

    Invasive species, range-expanding species, genetically modified organisms (GMOs), synthetic organisms, and emerging pathogens increasingly affect the human environment. We propose a framework that allows comparison of consecutive stages that such novel organisms go through. The framework provides a common terminology for novel organisms, facilitating knowledge exchange among researchers, managers, and policy makers that work on, or have to make effective decisions about, novel organisms. The framework also indicates that knowledge about the causes and consequences of stage transitions for the better studied novel organisms, such as invasive species, can be transferred to more poorly studied ones, such as GMOs and emerging pathogens. Finally, the framework advances understanding of how climate change can affect the establishment, spread, and impacts of novel organisms, and how biodiversity affects, and is affected by, novel organisms. PMID:23456779

  17. Novel organisms: comparing invasive species, GMOs, and emerging pathogens.

    PubMed

    Jeschke, Jonathan M; Keesing, Felicia; Ostfeld, Richard S

    2013-09-01

    Invasive species, range-expanding species, genetically modified organisms (GMOs), synthetic organisms, and emerging pathogens increasingly affect the human environment. We propose a framework that allows comparison of consecutive stages that such novel organisms go through. The framework provides a common terminology for novel organisms, facilitating knowledge exchange among researchers, managers, and policy makers that work on, or have to make effective decisions about, novel organisms. The framework also indicates that knowledge about the causes and consequences of stage transitions for the better studied novel organisms, such as invasive species, can be transferred to more poorly studied ones, such as GMOs and emerging pathogens. Finally, the framework advances understanding of how climate change can affect the establishment, spread, and impacts of novel organisms, and how biodiversity affects, and is affected by, novel organisms.

  18. Comparative Pathogenicity of United Kingdom Isolates of the Emerging Pathogen Candida auris and Other Key Pathogenic Candida Species

    PubMed Central

    Szekely, Adrien; Johnson, Elizabeth M.

    2016-01-01

    ABSTRACT Candida auris, first described in 2009, has since emerged as an important, multidrug-resistant, nosocomial agent of candidemia, with large outbreaks reported worldwide and high mortality rates associated with therapeutic failure. The current study employed C. auris isolates from a variety of centers in the United Kingdom to evaluate the pathogenicity of this emerging pathogen compared to that of other common pathogenic yeast species in the invertebrate Galleria mellonella infection model. We showed that C. auris isolates differ in their growth characteristics in vitro, with a proportion of isolates failing to release daughter cells after budding, resulting in the formation of large aggregates of cells that cannot be physically disrupted. Our results also demonstrate strain-specific differences in the behavior of C. auris in G. mellonella, with the aggregate-forming isolates exhibiting significantly less pathogenicity than their nonaggregating counterparts. Importantly, the nonaggregating isolates exhibited pathogenicity comparable to that of C. albicans, which is currently accepted as the most pathogenic member of the genus, despite the fact that C. auris isolates do not produce hyphae and produce only rudimentary pseudohyphae either in vitro or in G. mellonella. IMPORTANCE The incidence of invasive candidiasis, which includes candidemia and deep tissue infections, continues to rise and is associated with considerable mortality rates. Candida albicans remains the most common cause of invasive candidiasis, although the prevalence of non-albicans species has increased over recent years. Since its first description in 2009, Candida auris has emerged as a serious nosocomial health risk, with widespread outbreaks in numerous hospitals worldwide. However, despite receiving considerable attention, little is known concerning the pathogenicity of this emerging fungal pathogen. Here, using the Galleria mellonella insect systemic infection model, we show

  19. Comparative Pathogenicity of United Kingdom Isolates of the Emerging Pathogen Candida auris and Other Key Pathogenic Candida Species.

    PubMed

    Borman, Andrew M; Szekely, Adrien; Johnson, Elizabeth M

    2016-01-01

    Candida auris, first described in 2009, has since emerged as an important, multidrug-resistant, nosocomial agent of candidemia, with large outbreaks reported worldwide and high mortality rates associated with therapeutic failure. The current study employed C. auris isolates from a variety of centers in the United Kingdom to evaluate the pathogenicity of this emerging pathogen compared to that of other common pathogenic yeast species in the invertebrate Galleria mellonella infection model. We showed that C. auris isolates differ in their growth characteristics in vitro, with a proportion of isolates failing to release daughter cells after budding, resulting in the formation of large aggregates of cells that cannot be physically disrupted. Our results also demonstrate strain-specific differences in the behavior of C. auris in G. mellonella, with the aggregate-forming isolates exhibiting significantly less pathogenicity than their nonaggregating counterparts. Importantly, the nonaggregating isolates exhibited pathogenicity comparable to that of C. albicans, which is currently accepted as the most pathogenic member of the genus, despite the fact that C. auris isolates do not produce hyphae and produce only rudimentary pseudohyphae either in vitro or in G. mellonella. IMPORTANCE The incidence of invasive candidiasis, which includes candidemia and deep tissue infections, continues to rise and is associated with considerable mortality rates. Candida albicans remains the most common cause of invasive candidiasis, although the prevalence of non-albicans species has increased over recent years. Since its first description in 2009, Candida auris has emerged as a serious nosocomial health risk, with widespread outbreaks in numerous hospitals worldwide. However, despite receiving considerable attention, little is known concerning the pathogenicity of this emerging fungal pathogen. Here, using the Galleria mellonella insect systemic infection model, we show strain

  20. Comparative Pathogenicity of United Kingdom Isolates of the Emerging Pathogen Candida auris and Other Key Pathogenic Candida Species.

    PubMed

    Borman, Andrew M; Szekely, Adrien; Johnson, Elizabeth M

    2016-01-01

    Candida auris, first described in 2009, has since emerged as an important, multidrug-resistant, nosocomial agent of candidemia, with large outbreaks reported worldwide and high mortality rates associated with therapeutic failure. The current study employed C. auris isolates from a variety of centers in the United Kingdom to evaluate the pathogenicity of this emerging pathogen compared to that of other common pathogenic yeast species in the invertebrate Galleria mellonella infection model. We showed that C. auris isolates differ in their growth characteristics in vitro, with a proportion of isolates failing to release daughter cells after budding, resulting in the formation of large aggregates of cells that cannot be physically disrupted. Our results also demonstrate strain-specific differences in the behavior of C. auris in G. mellonella, with the aggregate-forming isolates exhibiting significantly less pathogenicity than their nonaggregating counterparts. Importantly, the nonaggregating isolates exhibited pathogenicity comparable to that of C. albicans, which is currently accepted as the most pathogenic member of the genus, despite the fact that C. auris isolates do not produce hyphae and produce only rudimentary pseudohyphae either in vitro or in G. mellonella. IMPORTANCE The incidence of invasive candidiasis, which includes candidemia and deep tissue infections, continues to rise and is associated with considerable mortality rates. Candida albicans remains the most common cause of invasive candidiasis, although the prevalence of non-albicans species has increased over recent years. Since its first description in 2009, Candida auris has emerged as a serious nosocomial health risk, with widespread outbreaks in numerous hospitals worldwide. However, despite receiving considerable attention, little is known concerning the pathogenicity of this emerging fungal pathogen. Here, using the Galleria mellonella insect systemic infection model, we show strain

  1. Bacterial Toxins—Staphylococcal Enterotoxin B

    PubMed Central

    FRIES, BETTINA C.; VARSHNEY, AVANISH K.

    2015-01-01

    Staphylococcal enterotoxin B is one of the most potent bacterial superantigens that exerts profound toxic effects upon the immune system, leading to stimulation of cytokine release and inflammation. It is associated with food poisoning, nonmenstrual toxic shock, atopic dermatitis, asthma, and nasal polyps in humans. Currently, there is no treatment or vaccine available. Passive immunotherapy using monoclonal antibodies made in several different species has shown significant inhibition in in vitro studies and reduction in staphylococcal enterotoxin B-induced lethal shock in in vivo studies. This should encourage future endeavors to develop these antibodies as therapeutic reagents. PMID:26184960

  2. Chronological aging in conidia of pathogenic Aspergillus: Comparison between species.

    PubMed

    Oliveira, Manuela; Pereira, Clara; Bessa, Cláudia; Araujo, Ricardo; Saraiva, Lucília

    2015-11-01

    Aspergillus fumigatus, Aspergillus flavus, Aspergillus terreus and Aspergillus niger are common airborne fungi, and the most frequent causative agents of human fungal infections. However, the resistance and lifetime persistence of these fungi in the atmosphere, and the mechanism of aging of Aspergillus conidia are unknown.With this work, we intended to study the processes underlying conidial aging of these four relevant and pathogenic Aspergillus species. Chronological aging was therefore evaluated in A. fumigatus, A. flavus, A. terreus and A. niger conidia exposed to environmental and human body temperatures. The results showed that the aging process in Aspergillus conidia involves apoptosis,with metacaspase activation, DNA fragmentation, and reactive oxygen species production, associated with secondary necrosis. Distinct results were observed for the selected pathogenic species. At environmental conditions, A. niger was the species with the highest resistance to aging, indicating a higher adaption to environmental conditions, whereas A. flavus followed by A. terreus were the most sensitive species. At higher temperatures (37 °C), A. fumigatus presented the longest lifespan, in accordance with its good adaptation to the human body temperature. Altogether,with this work new insights regarding conidia aging are provided, which may be useful when designing treatments for aspergillosis.

  3. Isolation of pathogenic Aspergillus species from commercially-prepared potting media.

    PubMed

    Kenyon, E M; Russell, L H; McMurray, D N

    1984-09-30

    Twelve commercially-prepared potting soils were screened for the presence of pathogenic Aspergillus species. Pathogenic Aspergillus species were isolated from 67% of the soils. A fumigatus was isolated from 42% and A. flavus and A. niger from 33%.

  4. Phylogenetic placement of plant pathogenic Sclerotium species among teleomorph genera.

    PubMed

    Xu, Zhihan; Harrington, Thomas C; Gleason, Mark L; Batzer, Jean C

    2010-01-01

    Phylogenetic analyses and morphological characteristics were used to assess the taxonomic placement of eight plant-pathogenic Sclerotium species. Members of this genus produce only sclerotia and no fruiting bodies or spores, so Sclerotium species have been difficult to place taxonomically. Sequences of rDNA large subunit (LSU) and internal transcribed spacer (ITS) regions were determined for isolates of Sclerotium cepivorum, S. coffeicola, S. denigrans, S. hydrophilum, Ceratorhiza oryzae-sativae, S. perniciosum, S. rhizodes, S. rolfsii and S. rolfsii var. delphinii. Parsimony analysis grouped two species previously thought to be in the Basidiomycota, S. denigrans and S. perniciosum, within the Ascomycota; these species were found to have affinities with the teleomorph genera Sclerotinia and Stromatinia and the asexual Sclerotium cepivorum, which was known earlier to be related to Sclerotinia species. The other Sclerotium species were placed in one of two basidiomycetous groups, genera Athelia or Ceratobasidium. Based on rDNA analysis and morphology the basidiomycetous Sclerotium hydrophilum and S. rhizodes were transferred to genus Ceratorhiza, the anamorph of Ceratobasidium species. Sclerotium coffeicola was found to be close to S. rolfsii var. delphinii and S. rolfsii var. rolfsii, which was shown earlier to have an Athelia teleomorph. PMID:20361501

  5. Skin-associated Bacillus, staphylococcal and micrococcal species from the house dust mite, Dermatophagoides pteronyssinus and bacteriolytic enzymes.

    PubMed

    Tang, Vivian H; Chang, Barbara J; Srinivasan, Ambuja; Mathaba, Leslie T; Harnett, Gerald B; Stewart, Geoffrey A

    2013-12-01

    Dust mites produce bacteriolytic enzymes, one of which belongs to the NlpC/P60 superfamily comprising bacterial and fungal proteins. Whether this enzyme is derived from the mite or from mite-associated microbes is unclear. To this end, the bacteriology of mites per se, and carpet and mattress dust from a group of asthmatic children and their parents was investigated. Dust from parents' and children's mattresses yielded significantly more colony forming units compared with dust from their corresponding carpets. Zymography demonstrated some dusts contained bacteriolytic enzymes, and in nine of the twelve dust samples from three of five houses examined, a prominent bacteriolytic band was obtained that corresponded to the mite band, although in one home, other lytic bands were detected. Fifty bacterial isolates were obtained from surface-sterilised, commercially obtained Dermatophagoides pteronyssinus. 16S rRNA, tuf and rpoB gene sequencing of nine Gram-positive isolates identified them as Bacillus cereus, B. licheniformis, Staphylococcus aureus, S. epidermidis, S. capitis and Micrococcus luteus, known human skin commensals. 16S rRNA sequence homologies of four of the nine isolates identified as B. licheniformis formed a distinct phylogenetic cluster. All species secreted lytic enzymes during culture although the lytic profiles obtained differed between the rods and the cocci, and none of the bands detected corresponded to those observed in dust or mites. In conclusion, mites harbour a variety of bacterial species often associated with human skin and house dusts contain bacteriolytic enzymes that may be mite-derived. The identification of a novel cluster of B. licheniformis isolates suggests an ecological adaptation to laboratory-reared D. pteronyssinus. It remains to be determined whether the previously described mite-associated 14 K lytic enzyme is derived from a microbial source.

  6. The Staphylococcal Biofilm: Adhesins, regulation, and host response

    PubMed Central

    Paharik, Alexandra E.; Horswill, Alexander R.

    2015-01-01

    The Staphylococci comprise a diverse genus of Gram-positive, non-motile commensal organisms that inhabit the skin and mucous membranes of humans and other mammals. In general, Staphylococci are benign members of the natural flora, but many species have the capacity to be opportunistic pathogens, mainly infecting individuals who have medical device implants or are otherwise immunocompromised. S. aureus and S. epidermidis are a major source of hospital-acquired infections and are the most common causes of surgical site infections and central line-associated bloodstream infections. The ability of Staphylococci to form biofilms in vivo makes them highly resistant to chemotherapeutics and leads to chronic diseases. These biofilm infections include osteomyelitis, endocarditis, medical device implants, and persistence in the cystic fibrosis lung. Here, we provide a comprehensive analysis of our current understanding of Staphylococcal biofilm formation, with an emphasis on adhesins and regulation, while also addressing how Staphylococcal biofilms interact with the immune system. On the whole, this review will provide a thorough picture of biofilm formation of the Staphylococcus genus and how this mode of growth impacts the host. PMID:27227309

  7. The Staphylococcal Biofilm: Adhesins, Regulation, and Host Response.

    PubMed

    Paharik, Alexandra E; Horswill, Alexander R

    2016-04-01

    The staphylococci comprise a diverse genus of Gram-positive, nonmotile commensal organisms that inhabit the skin and mucous membranes of humans and other mammals. In general, staphylococci are benign members of the natural flora, but many species have the capacity to be opportunistic pathogens, mainly infecting individuals who have medical device implants or are otherwise immunocompromised. Staphylococcus aureus and Staphylococcus epidermidis are major sources of hospital-acquired infections and are the most common causes of surgical site infections and medical device-associated bloodstream infections. The ability of staphylococci to form biofilms in vivo makes them highly resistant to chemotherapeutics and leads to chronic diseases. These biofilm infections include osteomyelitis, endocarditis, medical device infections, and persistence in the cystic fibrosis lung. Here, we provide a comprehensive analysis of our current understanding of staphylococcal biofilm formation, with an emphasis on adhesins and regulation, while also addressing how staphylococcal biofilms interact with the immune system. On the whole, this review will provide a thorough picture of biofilm formation of the staphylococcus genus and how this mode of growth impacts the host. PMID:27227309

  8. Tool for Quantification of Staphylococcal Enterotoxin Gene Expression in Cheese▿

    PubMed Central

    Duquenne, Manon; Fleurot, Isabelle; Aigle, Marina; Darrigo, Claire; Borezée-Durant, Elise; Derzelle, Sylviane; Bouix, Marielle; Deperrois-Lafarge, Véronique; Delacroix-Buchet, Agnès

    2010-01-01

    Cheese is a complex and dynamic microbial ecosystem characterized by the presence of a large variety of bacteria, yeasts, and molds. Some microorganisms, including species of lactobacilli or lactococci, are known to contribute to the organoleptic quality of cheeses, whereas the presence of other microorganisms may lead to spoilage or constitute a health risk. Staphylococcus aureus is recognized worldwide as an important food-borne pathogen, owing to the production of enterotoxins in food matrices. In order to study enterotoxin gene expression during cheese manufacture, we developed an efficient procedure to recover total RNA from cheese and applied a robust strategy to study gene expression by reverse transcription-quantitative PCR (RT-qPCR). This method yielded pure preparations of undegraded RNA suitable for RT-qPCR. To normalize RT-qPCR data, expression of 10 potential reference genes was investigated during S. aureus growth in milk and in cheese. The three most stably expressed reference genes during cheese manufacture were ftsZ, pta, and gyrB, and these were used as internal controls for RT-qPCR of the genes sea and sed, encoding staphylococcal enterotoxins A and D, respectively. Expression of these staphylococcal enterotoxin genes was monitored during the first 72 h of the cheese-making process, and mRNA data were correlated with enterotoxin production. PMID:20061456

  9. Tool for quantification of staphylococcal enterotoxin gene expression in cheese.

    PubMed

    Duquenne, Manon; Fleurot, Isabelle; Aigle, Marina; Darrigo, Claire; Borezée-Durant, Elise; Derzelle, Sylviane; Bouix, Marielle; Deperrois-Lafarge, Véronique; Delacroix-Buchet, Agnès

    2010-03-01

    Cheese is a complex and dynamic microbial ecosystem characterized by the presence of a large variety of bacteria, yeasts, and molds. Some microorganisms, including species of lactobacilli or lactococci, are known to contribute to the organoleptic quality of cheeses, whereas the presence of other microorganisms may lead to spoilage or constitute a health risk. Staphylococcus aureus is recognized worldwide as an important food-borne pathogen, owing to the production of enterotoxins in food matrices. In order to study enterotoxin gene expression during cheese manufacture, we developed an efficient procedure to recover total RNA from cheese and applied a robust strategy to study gene expression by reverse transcription-quantitative PCR (RT-qPCR). This method yielded pure preparations of undegraded RNA suitable for RT-qPCR. To normalize RT-qPCR data, expression of 10 potential reference genes was investigated during S. aureus growth in milk and in cheese. The three most stably expressed reference genes during cheese manufacture were ftsZ, pta, and gyrB, and these were used as internal controls for RT-qPCR of the genes sea and sed, encoding staphylococcal enterotoxins A and D, respectively. Expression of these staphylococcal enterotoxin genes was monitored during the first 72 h of the cheese-making process, and mRNA data were correlated with enterotoxin production.

  10. The transferrin-iron import system from pathogenic Neisseria species.

    PubMed

    Noinaj, Nicholas; Buchanan, Susan K; Cornelissen, Cynthia Nau

    2012-10-01

    Two pathogenic species within the genus Neisseria cause the diseases gonorrhoea and meningitis. While vaccines are available to protect against four N. meningitidis serogroups, there is currently no commercial vaccine to protect against serogroup B or against N. gonorrhoeae. Moreover, the available vaccines have significant limitations and with antibiotic resistance becoming an alarming issue, the search for effective vaccine targets to elicit long-lasting protection against Neisseria species is becoming more urgent. One strategy for vaccine development has targeted the neisserial iron import systems. Without iron, the Neisseriae cannot survive and, therefore, these iron import systems tend to be relatively well conserved and are promising vaccine targets, having the potential to offer broad protection against both gonococcal and meningococcal infections. These efforts have been boosted by recent reports of the crystal structures of the neisserial receptor proteins TbpA and TbpB, each solved in complex with human transferrin, an iron binding protein normally responsible for delivering iron to human cells. Here, we review the recent structural reports and put them into perspective with available functional studies in order to derive the mechanism(s) for how the pathogenic Neisseriae are able to hijack human iron transport systems for their own survival and pathogenesis. PMID:22957710

  11. The transferrin-iron import system from pathogenic Neisseria species.

    PubMed

    Noinaj, Nicholas; Buchanan, Susan K; Cornelissen, Cynthia Nau

    2012-10-01

    Two pathogenic species within the genus Neisseria cause the diseases gonorrhoea and meningitis. While vaccines are available to protect against four N. meningitidis serogroups, there is currently no commercial vaccine to protect against serogroup B or against N. gonorrhoeae. Moreover, the available vaccines have significant limitations and with antibiotic resistance becoming an alarming issue, the search for effective vaccine targets to elicit long-lasting protection against Neisseria species is becoming more urgent. One strategy for vaccine development has targeted the neisserial iron import systems. Without iron, the Neisseriae cannot survive and, therefore, these iron import systems tend to be relatively well conserved and are promising vaccine targets, having the potential to offer broad protection against both gonococcal and meningococcal infections. These efforts have been boosted by recent reports of the crystal structures of the neisserial receptor proteins TbpA and TbpB, each solved in complex with human transferrin, an iron binding protein normally responsible for delivering iron to human cells. Here, we review the recent structural reports and put them into perspective with available functional studies in order to derive the mechanism(s) for how the pathogenic Neisseriae are able to hijack human iron transport systems for their own survival and pathogenesis.

  12. Evidence for two evolutionary lineages of highly pathogenic Yersinia species.

    PubMed Central

    Rakin, A; Urbitsch, P; Heesemann, J

    1995-01-01

    Sensitivity to Yersinia pestis bacteriocin pesticin correlates with the existence of two groups of human pathogenic yersiniae, mouse lethal and mouse nonlethal. The presence of the outer membrane pesticin receptor (FyuA) in mouse-lethal yersiniae is a prerequisite for pesticin sensitivity. Genes that code for FyuA (fyuA) were identified and sequenced from pesticin-sensitive bacteria, including Y. enterocolitica biotype 1B (serotypes O8; O13, O20, and O21), Y. pseudotuberculosis serotype O1, Y. pestis, two known pesticin-sensitive Escherichia coli isolates (E. coli Phi and E. coli CA42), and two newly discovered pesticin-sensitive isolates, E. coli K49 and K235. A 2,318-bp fyuA sequence was shown to be highly conserved in all pesticin-sensitive bacteria, including E. coli strains (DNA sequence homology was 98.5 to 99.9%). The same degree of DNA homology (97.8 to 100%) was established for the sequenced 276-bp fragment of the irp2 gene that encodes high-molecular-weight protein 2, which is also thought to be involved in the expression of virulence by Yersinia species. Highly conserved irp2 was also found in all pesticin-sensitive E. coli strains. On the basis of the fyuA and irp2 sequence homologies, two evolutionary groups of highly pathogenic Yersinia species can be established. One group includes Y. enterocolitica biotype 1B strains, while the second includes Y. pestis, Y. pseudotuberculosis serotype O1, and irp2-positive Y. pseudotuberculosis serotype O3 strains. E. coli Phi, CA42, K49, and K235 belong to the second group. The possible proximity of these two iron-regulated genes (fyuA and irp2), as well as their high levels of sequence conservation and similar G+C contents (56.2 and 59.8 mol%), leads to the assumption that these two genes may represent part of an unstable pathogenicity island that has been acquired by pesticin-sensitive bacteria as a result of a horizontal transfer. PMID:7730256

  13. Host antioxidant enzymes and TLR-2 neutralization modulate intracellular survival of Staphylococcus aureus: Evidence of the effect of redox balance on host pathogen relationship during acute staphylococcal infection.

    PubMed

    Nandi, Ajeya; Bishayi, Biswadev

    2015-12-01

    Staphylococcus aureus is an important pathogen in bone disease and innate immune recognition receptor, TLR-2 is reported to be crucial for inflammatory bone loss. Role of TLR-2 in bacterial clearance and cytokine response to S. aureus infection in murine bone marrow macrophages has been reported but the role of host derived ROS in host-pathogen relationship still remains an obvious question. In the present study, blocking of SOD and catalase in TLR-2 neutralized fresh bone marrow cells (FBMC) with Diethyldithiocarbamic acid (DDC) and 3-Amino-1,2,4-triazole (ATZ), separately, during acute S. aureus infection, produces moderate level of ROS and limits inflammation as compared with only TLR-2 non-neutralized condition and leads to decreased bacterial count compared with only TLR-2 neutralized condition. In summary, host SOD and catalase modulates ROS generation, cytokine levels and TLR-2 expression in FBMCs during acute S. aureus infection which might be useful in the alleviation of S. aureus infection and bone loss.

  14. Direct, Specific and Rapid Detection of Staphylococcal Proteins and Exotoxins Using a Multiplex Antibody Microarray

    PubMed Central

    Stieber, Bettina; Monecke, Stefan; Müller, Elke; Büchler, Joseph; Ehricht, Ralf

    2015-01-01

    Background S. aureus is a pathogen in humans and animals that harbors a wide variety of virulence factors and resistance genes. This bacterium can cause a wide range of mild to life-threatening diseases. In the latter case, fast diagnostic procedures are important. In routine diagnostic laboratories, several genotypic and phenotypic methods are available to identify S. aureus strains and determine their resistances. However, there is a demand for multiplex routine diagnostic tests to directly detect staphylococcal toxins and proteins. Methods In this study, an antibody microarray based assay was established and validated for the rapid detection of staphylococcal markers and exotoxins. The following targets were included: staphylococcal protein A, penicillin binding protein 2a, alpha- and beta-hemolysins, Panton Valentine leukocidin, toxic shock syndrome toxin, enterotoxins A and B as well as staphylokinase. All were detected simultaneously within a single experiment, starting from a clonal culture on standard media. The detection of bound proteins was performed using a new fluorescence reading device for microarrays. Results 110 reference strains and clinical isolates were analyzed using this assay, with a DNA microarray for genotypic characterization performed in parallel. The results showed a general high concordance of genotypic and phenotypic data. However, genotypic analysis found the hla gene present in all S. aureus isolates but its expression under given conditions depended on the clonal complex affiliation of the actual isolate. Conclusions The multiplex antibody assay described herein allowed a rapid and reliable detection of clinically relevant staphylococcal toxins as well as resistance- and species-specific markers. PMID:26624622

  15. Identification of Clinical Staphylococcal Isolates from Humans by Internal Transcribed Spacer PCR

    PubMed Central

    Couto, Isabel; Pereira, Sandro; Miragaia, Maria; Sanches, Ilda Santos; de Lencastre, Hermínia

    2001-01-01

    The emergence of coagulase-negative staphylococci not only as human pathogens but also as reservoirs of antibiotic resistance determinants requires the deployment and development of methods for their rapid and reliable identification. Internal transcribed spacer-PCR (ITS-PCR) was used to identify a collection of 617 clinical staphylococcal isolates. The amplicons were resolved in high-resolution agarose gels and visually compared with the patterns obtained for the control strains of 29 staphylococcal species. Of the 617 isolates studied, 592 (95.95%) were identified by ITS-PCR and included 11 species: 302 isolates of Staphylococcus epidermidis, 157 of S. haemolyticus, 79 of S. aureus, 21 of S. hominis, 14 of S. saprophyticus, 8 of S. warneri, 6 of S. simulans, 2 of S. lugdunensis, and 1 each of S. caprae, S. carnosus, and S. cohnii. All species analyzed had unique ITS-PCR patterns, although some were very similar, namely, the group S. saprophyticus, S. cohnii, S. gallinarum, S. xylosus, S. lentus, S. equorum, and S. chromogenes, the pair S. schleiferi and S. vitulus, and the pair S. piscifermentans and S. carnosus. Four species, S. aureus, S. caprae, S. haemolyticus, and S. lugdunensis, showed polymorphisms on their ITS-PCR patterns. ITS-PCR proved to be a valuable alternative for the identification of staphylococci, offering, within the same response time and at lower cost, higher reliability than the currently available commercial systems. PMID:11526135

  16. Database of host-pathogen and related species interactions, and their global distribution

    PubMed Central

    Wardeh, Maya; Risley, Claire; McIntyre, Marie Kirsty; Setzkorn, Christian; Baylis, Matthew

    2015-01-01

    Interactions between species, particularly where one is likely to be a pathogen of the other, as well as the geographical distribution of species, have been systematically extracted from various web-based, free-access sources, and assembled with the accompanying evidence into a single database. The database attempts to answer questions such as what are all the pathogens of a host, and what are all the hosts of a pathogen, what are all the countries where a pathogen was found, and what are all the pathogens found in a country. Two datasets were extracted from the database, focussing on species interactions and species distribution, based on evidence published between 1950–2012. The quality of their evidence was checked and verified against well-known, alternative, datasets of pathogens infecting humans, domestic animals and wild mammals. The presented datasets provide a valuable resource for researchers of infectious diseases of humans and animals, including zoonoses. PMID:26401317

  17. Analyzing the Differences and Preferences of Pathogenic and Nonpathogenic Prokaryote Species

    NASA Astrophysics Data System (ADS)

    Nolen, L.; Duong, K.; Heim, N. A.; Payne, J.

    2015-12-01

    A limited amount of knowledge exists on the large-scale characteristics and differences of pathogenic species in comparison to all prokaryotes. Pathogenic species, like other prokaryotes, have attributes specific to their environment and lifestyles. However, because they have evolved to coexist inside their hosts, the conditions they occupy may be more limited than those of non-pathogenic species. In this study we investigate the possibility of divergent evolution between pathogenic and non-pathogenic species by examining differences that may have evolved as a result of the need to adapt to their host. For this research we analyzed data collected from over 1900 prokaryotic species and performed t-tests using R to quantify potential differences in preferences. To examine the possible divergences from nonpathogenic bacteria, we focused on three variables: cell biovolume, preferred environmental pH, and preferred environmental temperature. We also looked at differences between pathogenic and nonpathogenic species belonging to the same phylum. Our results suggest a strong divergence in abiotic preferences between the two groups, with pathogens occupying a much smaller range of temperatures and pHs than their non-pathogenic counterparts. However, while the median biovolume is different when comparing pathogens and nonpathogens, we cannot conclude that the mean values are significantly different from each other. In addition, we found evidence of convergent evolution, as the temperature and pH preferences of pathogenic bacteria species from different phlya all approach the same values. Pathogenic species do not, however, all approach the same biovolume values, suggesting that specific pH and temperature preferences are more characteristic of pathogens than certain biovolumes.

  18. The pathogen biology, identification and management of Rhizoctonia species with emphasis on isolates infecting turfgrasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    R. solani is an economically important soilborne basidiomycetous pathogen of worldwide distribution and it is known to attack at least 188 species of higher plants, including crops, vegetables, ornamentals, forest trees and turfgrasses. The pathogenic isolates may belong to multiple genera and speci...

  19. The genomic organization of plant pathogenicity in Fusarium species.

    PubMed

    Rep, Martijn; Kistler, H Corby

    2010-08-01

    Comparative genomics is a powerful tool to infer the molecular basis of fungal pathogenicity and its evolution by identifying differences in gene content and genomic organization between fungi with different hosts or modes of infection. Through comparative analysis, pathogenicity-related chromosomes have been identified in Fusarium oxysporum and Fusarium solani that contain genes for host-specific virulence. Lateral transfer of pathogenicity chromosomes, inferred from genomic data, now has been experimentally confirmed. Likewise, comparative genomics reveals the evolutionary relationships among toxin gene clusters whereby the loss and gain of genes from the cluster may be understood in an evolutionary context of toxin diversification. The genomic milieu of effector genes, encoding small secreted proteins, also suggests mechanisms that promote genetic diversification for the benefit of the pathogen.

  20. What Makes a Bacterial Species Pathogenic?:Comparative Genomic Analysis of the Genus Leptospira.

    PubMed

    Fouts, Derrick E; Matthias, Michael A; Adhikarla, Haritha; Adler, Ben; Amorim-Santos, Luciane; Berg, Douglas E; Bulach, Dieter; Buschiazzo, Alejandro; Chang, Yung-Fu; Galloway, Renee L; Haake, David A; Haft, Daniel H; Hartskeerl, Rudy; Ko, Albert I; Levett, Paul N; Matsunaga, James; Mechaly, Ariel E; Monk, Jonathan M; Nascimento, Ana L T; Nelson, Karen E; Palsson, Bernhard; Peacock, Sharon J; Picardeau, Mathieu; Ricaldi, Jessica N; Thaipandungpanit, Janjira; Wunder, Elsio A; Yang, X Frank; Zhang, Jun-Jie; Vinetz, Joseph M

    2016-02-01

    Leptospirosis, caused by spirochetes of the genus Leptospira, is a globally widespread, neglected and emerging zoonotic disease. While whole genome analysis of individual pathogenic, intermediately pathogenic and saprophytic Leptospira species has been reported, comprehensive cross-species genomic comparison of all known species of infectious and non-infectious Leptospira, with the goal of identifying genes related to pathogenesis and mammalian host adaptation, remains a key gap in the field. Infectious Leptospira, comprised of pathogenic and intermediately pathogenic Leptospira, evolutionarily diverged from non-infectious, saprophytic Leptospira, as demonstrated by the following computational biology analyses: 1) the definitive taxonomy and evolutionary relatedness among all known Leptospira species; 2) genomically-predicted metabolic reconstructions that indicate novel adaptation of infectious Leptospira to mammals, including sialic acid biosynthesis, pathogen-specific porphyrin metabolism and the first-time demonstration of cobalamin (B12) autotrophy as a bacterial virulence factor; 3) CRISPR/Cas systems demonstrated only to be present in pathogenic Leptospira, suggesting a potential mechanism for this clade's refractoriness to gene targeting; 4) finding Leptospira pathogen-specific specialized protein secretion systems; 5) novel virulence-related genes/gene families such as the Virulence Modifying (VM) (PF07598 paralogs) proteins and pathogen-specific adhesins; 6) discovery of novel, pathogen-specific protein modification and secretion mechanisms including unique lipoprotein signal peptide motifs, Sec-independent twin arginine protein secretion motifs, and the absence of certain canonical signal recognition particle proteins from all Leptospira; and 7) and demonstration of infectious Leptospira-specific signal-responsive gene expression, motility and chemotaxis systems. By identifying large scale changes in infectious (pathogenic and intermediately pathogenic

  1. What Makes a Bacterial Species Pathogenic?:Comparative Genomic Analysis of the Genus Leptospira.

    PubMed

    Fouts, Derrick E; Matthias, Michael A; Adhikarla, Haritha; Adler, Ben; Amorim-Santos, Luciane; Berg, Douglas E; Bulach, Dieter; Buschiazzo, Alejandro; Chang, Yung-Fu; Galloway, Renee L; Haake, David A; Haft, Daniel H; Hartskeerl, Rudy; Ko, Albert I; Levett, Paul N; Matsunaga, James; Mechaly, Ariel E; Monk, Jonathan M; Nascimento, Ana L T; Nelson, Karen E; Palsson, Bernhard; Peacock, Sharon J; Picardeau, Mathieu; Ricaldi, Jessica N; Thaipandungpanit, Janjira; Wunder, Elsio A; Yang, X Frank; Zhang, Jun-Jie; Vinetz, Joseph M

    2016-02-01

    Leptospirosis, caused by spirochetes of the genus Leptospira, is a globally widespread, neglected and emerging zoonotic disease. While whole genome analysis of individual pathogenic, intermediately pathogenic and saprophytic Leptospira species has been reported, comprehensive cross-species genomic comparison of all known species of infectious and non-infectious Leptospira, with the goal of identifying genes related to pathogenesis and mammalian host adaptation, remains a key gap in the field. Infectious Leptospira, comprised of pathogenic and intermediately pathogenic Leptospira, evolutionarily diverged from non-infectious, saprophytic Leptospira, as demonstrated by the following computational biology analyses: 1) the definitive taxonomy and evolutionary relatedness among all known Leptospira species; 2) genomically-predicted metabolic reconstructions that indicate novel adaptation of infectious Leptospira to mammals, including sialic acid biosynthesis, pathogen-specific porphyrin metabolism and the first-time demonstration of cobalamin (B12) autotrophy as a bacterial virulence factor; 3) CRISPR/Cas systems demonstrated only to be present in pathogenic Leptospira, suggesting a potential mechanism for this clade's refractoriness to gene targeting; 4) finding Leptospira pathogen-specific specialized protein secretion systems; 5) novel virulence-related genes/gene families such as the Virulence Modifying (VM) (PF07598 paralogs) proteins and pathogen-specific adhesins; 6) discovery of novel, pathogen-specific protein modification and secretion mechanisms including unique lipoprotein signal peptide motifs, Sec-independent twin arginine protein secretion motifs, and the absence of certain canonical signal recognition particle proteins from all Leptospira; and 7) and demonstration of infectious Leptospira-specific signal-responsive gene expression, motility and chemotaxis systems. By identifying large scale changes in infectious (pathogenic and intermediately pathogenic

  2. What Makes a Bacterial Species Pathogenic?:Comparative Genomic Analysis of the Genus Leptospira

    PubMed Central

    Fouts, Derrick E.; Matthias, Michael A.; Adhikarla, Haritha; Adler, Ben; Amorim-Santos, Luciane; Berg, Douglas E.; Bulach, Dieter; Buschiazzo, Alejandro; Chang, Yung-Fu; Galloway, Renee L.; Haake, David A.; Haft, Daniel H.; Hartskeerl, Rudy; Ko, Albert I.; Levett, Paul N.; Matsunaga, James; Mechaly, Ariel E.; Monk, Jonathan M.; Nascimento, Ana L. T.; Nelson, Karen E.; Palsson, Bernhard; Peacock, Sharon J.; Picardeau, Mathieu; Ricaldi, Jessica N.; Thaipandungpanit, Janjira; Wunder, Elsio A.; Yang, X. Frank; Zhang, Jun-Jie; Vinetz, Joseph M.

    2016-01-01

    Leptospirosis, caused by spirochetes of the genus Leptospira, is a globally widespread, neglected and emerging zoonotic disease. While whole genome analysis of individual pathogenic, intermediately pathogenic and saprophytic Leptospira species has been reported, comprehensive cross-species genomic comparison of all known species of infectious and non-infectious Leptospira, with the goal of identifying genes related to pathogenesis and mammalian host adaptation, remains a key gap in the field. Infectious Leptospira, comprised of pathogenic and intermediately pathogenic Leptospira, evolutionarily diverged from non-infectious, saprophytic Leptospira, as demonstrated by the following computational biology analyses: 1) the definitive taxonomy and evolutionary relatedness among all known Leptospira species; 2) genomically-predicted metabolic reconstructions that indicate novel adaptation of infectious Leptospira to mammals, including sialic acid biosynthesis, pathogen-specific porphyrin metabolism and the first-time demonstration of cobalamin (B12) autotrophy as a bacterial virulence factor; 3) CRISPR/Cas systems demonstrated only to be present in pathogenic Leptospira, suggesting a potential mechanism for this clade’s refractoriness to gene targeting; 4) finding Leptospira pathogen-specific specialized protein secretion systems; 5) novel virulence-related genes/gene families such as the Virulence Modifying (VM) (PF07598 paralogs) proteins and pathogen-specific adhesins; 6) discovery of novel, pathogen-specific protein modification and secretion mechanisms including unique lipoprotein signal peptide motifs, Sec-independent twin arginine protein secretion motifs, and the absence of certain canonical signal recognition particle proteins from all Leptospira; and 7) and demonstration of infectious Leptospira-specific signal-responsive gene expression, motility and chemotaxis systems. By identifying large scale changes in infectious (pathogenic and intermediately pathogenic

  3. REAL-TIME PCR DETECTION OF THREE HUMAN-PATHOGENIC SPECIES FROM THE MICROSPORIDIAL GENUS ENCEPHALITOZOON

    EPA Science Inventory

    Three microsporidial species from the genus Encephalitozoon, E. hellem, E. cuniculi and E. intestinalis, have emerged as important opportunistic pathogens of humans affecting organ transplant recipients, AIDS patients, and other immunocompromised patients. Even though these thre...

  4. Species interactions in occurrence data for a community of tick-transmitted pathogens

    PubMed Central

    Estrada-Peña, Agustín; de la Fuente, José

    2016-01-01

    Interactions between tick species, their realized range of hosts, the pathogens they carry and transmit, and the geographic distribution of species in the Western Palearctic were determined based on evidence published between 1970–2014. These relationships were linked to remotely sensed features of temperature and vegetation and used to extract the network of interactions among the organisms. The resulting datasets focused on niche overlap among ticks and hosts, species interactions, and the fraction of the environmental niche in which tick-borne pathogens may circulate as a result of interactions and overlapping environmental traits. The resulting datasets provide a valuable resource for researchers interested in tick-borne pathogens, as they conciliate the abiotic and biotic sides of their niche, allowing exploration of the importance of each host species acting as a vertebrate reservoir in the circulation of tick-transmitted pathogens in the environmental niche. PMID:27479213

  5. Extrolites of Aspergillus fumigatus and Other Pathogenic Species in Aspergillus Section Fumigati

    PubMed Central

    Frisvad, Jens C.; Larsen, Thomas O.

    2016-01-01

    Aspergillus fumigatus is an important opportunistic human pathogen known for its production of a large array of extrolites. Up to 63 species have been described in Aspergillus section Fumigati, some of which have also been reliably reported to be pathogenic, including A. felis, A. fischeri, A. fumigatiaffinis, A. fumisynnematus, A. hiratsukae, A. laciniosus, A. lentulus, A. novofumigatus, A. parafelis, A. pseudofelis, A. pseudoviridinutans, A. spinosus, A. thermomutatus, and A. udagawae. These species share the production of hydrophobins, melanins, and siderophores and ability to grow well at 37°C, but they only share some small molecule extrolites, that could be important factors in pathogenicity. According to the literature gliotoxin and other exometabolites can be contributing factors to pathogenicity, but these exometabolites are apparently not produced by all pathogenic species. It is our hypothesis that species unable to produce some of these metabolites can produce proxy-exometabolites that may serve the same function. We tabulate all exometabolites reported from species in Aspergillus section Fumigati and by comparing the profile of those extrolites, suggest that those producing many different kinds of exometabolites are potential opportunistic pathogens. The exometabolite data also suggest that the profile of exometabolites are highly specific and can be used for identification of these closely related species. PMID:26779142

  6. Emerging agents of phaeohyphomycosis: pathogenic species of Bipolaris and Exserohilum.

    PubMed Central

    McGinnis, M R; Rinaldi, M G; Winn, R E

    1986-01-01

    Study of numerous living isolates of Bipolaris, Drechslera, Exserohilum, and Helminthosporium spp., as well as a mycological assessment of published case reports of phaeohyphomycosis attributed to these fungi, showed that Bipolaris australiensis, B. hawaiiensis, B. spicifera, Exserohilum longirostratum, E. mcginnisii, and E. rostratum are well-documented pathogens. Conidial shape, septation, and size, hilar characteristics, the origin of the germ tube from the basal cell and, to a lesser extent, from other conidial cells, and the sequence and location of the conidial septa are useful criteria for distinguishing these taxa. Images PMID:3745423

  7. Molecular Epidemiology of Novel Pathogen “Brachyspira hampsonii” Reveals Relationships between Diverse Genetic Groups, Regions, Host Species, and Other Pathogenic and Commensal Brachyspira Species

    PubMed Central

    Mirajkar, Nandita S.; Bekele, Aschalew Z.; Chander, Yogesh Y.

    2015-01-01

    Outbreaks of bloody diarrhea in swine herds in the late 2000s signaled the reemergence of an economically significant disease, swine dysentery, in the United States. Investigations confirmed the emergence of a novel spirochete in swine, provisionally designated “Brachyspira hampsonii,” with two genetically distinct clades. Although it has since been detected in swine and migratory birds in Europe and North America, little is known about its genetic diversity or its relationships with other Brachyspira species. This study characterizes B. hampsonii using a newly developed multilocus sequence typing (MLST) approach and elucidates the diversity, distribution, population structure, and genetic relationships of this pathogen from diverse epidemiological sources globally. Genetic characterization of 81 B. hampsonii isolates, originating from six countries, with our newly established MLST scheme identified a total of 20 sequence types (STs) belonging to three clonal complexes (CCs). B. hampsonii showed a heterogeneous population structure with evidence of microevolution locally in swine production systems, while its clustering patterns showed associations with its epidemiological origins (country, swine production system, and host species). The close genetic relatedness of B. hampsonii isolates from different countries and host species highlights the importance of strict biosecurity control measures. A comparative analysis of 430 isolates representing seven Brachyspira species (pathogens and commensals) from 19 countries and 10 host species depicted clustering by microbial species. It revealed the close genetic relatedness of B. hampsonii with commensal Brachyspira species and also provided support for the two clades of B. hampsonii to be considered a single species. PMID:26135863

  8. Pathogenicity of the Korean H5N8 highly pathogenic avian influenza virus in commercial domestic poultry species.

    PubMed

    Lee, Dong-Hun; Kwon, Jung-Hoon; Noh, Jin-Yong; Park, Jae-Keun; Yuk, Seong-Su; Erdene-Ochir, Tseren-Ochir; Lee, Joong-Bok; Park, Seung-Yong; Choi, In-Soo; Lee, Sang-Won; Song, Chang-Seon

    2016-01-01

    In 2014, the highly pathogenic avian influenza (HPAI) virus H5N8 triggered outbreaks in wild birds and poultry farms in South Korea. In the present study, we investigated the pathogenicity of the H5N8 HPAI virus, belonging to the clade 2.3.4.4, in different species of poultry. For this, we examined clinical signs and viral shedding levels following intranasal inoculation of the virus in 3-week-old commercial layer chickens and quails, 10-week-old Korean native chickens, and 8-week-old Muscovy ducks. Intranasal inoculation with 10(6.0) viruses at 50% egg-infective dose resulted in 100% mortality in the layer chickens (8/8) and quails (4/4), but 60% and 0% deaths in the Korean native chickens (3/5) and Muscovy ducks (0/4), respectively. In addition, transmission of the inoculated virus to contact-exposed birds was evident in all the species used in this study. Based on our results, we conclude that the H5N8 HPAI virus has lower pathogenicity and transmissibility in poultry species compared with previously reported H5N1 HPAI viruses. PMID:26814367

  9. Some South African Rubiaceae Tree Leaf Extracts Have Antimycobacterial Activity Against Pathogenic and Non-pathogenic Mycobacterium Species.

    PubMed

    Aro, Abimbola O; Dzoyem, Jean P; Hlokwe, Tiny M; Madoroba, Evelyn; Eloff, Jacobus N; McGaw, Lyndy J

    2015-07-01

    Tuberculosis (TB) caused by Mycobacterium tuberculosis remains an ongoing threat to human health. Many plant species contain antimycobacterial compounds, which may serve as template molecules for new anti-TB drugs. The Rubiaceae family is the largest family of trees in southern Africa, and preliminary evidence revealed antimycobacterial activity in several species of the genus, motivating further studies. Leaf extracts of 15 tree species from the Rubiaceae family were screened for antimycobacterial activity against pathogenic M. tuberculosis and non-pathogenic Mycobacterium smegmatis, Mycobacterium aurum and Mycobacterium bovis BCG (Bacillus Calmette-Guérin) using a twofold serial microdilution assay. Cytotoxicity was determined using a tetrazolium-based colorimetric assay against C3A liver cells and Vero kidney cells. Minimum inhibitory concentration values as low as 0.04 mg/mL against M. smegmatis and M. tuberculosis were recorded. Activity against M. aurum was the best predictor of activity against pathogenic M. tuberculosis (correlation coefficient = 0.9). Bioautography indicated at least 40 different antimycobacterial compounds in the extracts. Cytotoxicity of the extracts varied, and Oxyanthus speciosus had the most promising selectivity index values. PMID:25857273

  10. Determination of fungal pathogens of common weed species in the vicinity of Tokat, Turkey.

    PubMed

    Kadioğlu, I; Karamanli, N; Yanar, Y

    2010-01-01

    This study was carried out to determine the fungal pathogens on Chenopodium album L., Cirsium arvense (L.) Scop., Convolvulus arvensis L., Cynodon dactylon (L.) Pers., Delphinium consolida L., Portulaca oleracea L., Rumex crispus L., Solanum nigrum L., Sorghum halepense (L.) Pers. and Xanthium strumarium L. which were common weed species of agricultural areas. Surveys were conducted in May-June and August-September in 2004-2005 growing seasons. During the surveys density and frequency of the above mentioned weed species were also determined and number of infected plants was counted in each sampling area. Infected weed samples were collected from each sampling point and brought to the laboratory in polyethylene bags and the pathogens were identified at genus or species level. As a result of two year surveys, ten fungal pathogens were determined on eight weed species. The most important fungal pathogens determined on common weed species were as follow; Peronospora farinosa (Fr.) Fr. on C. album, and Septoria convolvuli DC., Erysiphe convolvuli DC., and Puccinia punctiformis (Strauss) Roehrl. on C. arvensis. These fungal diseases were observed mainly on the weeds located at the borders of fields. Infection rates of these pathogens reached up to 21.2% in some of the survey areas. Further studies should be conducted to evaluate the efficacy of these pathogen under in vitro and in vivo conditions.

  11. Controls on pathogen species richness in plants introduced and native ranges: roles of residence time, range size and host traits

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction of hosts to new geographic regions allows them to escape many pathogens, raising two questions. How quickly do introduced hosts accumulate pathogens? Do the same factors control pathogen accumulation as in the native range? We analyzed fungal and viral pathogen species richness on 124 p...

  12. The effect of soil-borne pathogens depends on the abundance of host tree species.

    PubMed

    Liu, Yu; Fang, Suqin; Chesson, Peter; He, Fangliang

    2015-01-01

    The overarching issue for understanding biodiversity maintenance is how fitness advantages accrue to a species as it becomes rare, as this is the defining feature of stable coexistence mechanisms. Without these fitness advantages, average fitness differences between species will lead to exclusion. However, empirical evidence is lacking, especially for forests, due to the difficulty of manipulating density on a large-enough scale. Here we took advantage of naturally occurring contrasts in abundance between sites of a subtropical tree species, Ormosia glaberrima, to demonstrate how low-density fitness advantages accrue by the Janzen-Connell mechanism. The results showed that soil pathogens suppressed seedling recruitment of O. glaberrima when it is abundant but had little effect on the seedlings when it is at low density due to the lack of pathogens. The difference in seedling survival between abundant and low-density sites demonstrates strong dependence of pathogenic effect on the abundance of host species. PMID:26632594

  13. The effect of soil-borne pathogens depends on the abundance of host tree species

    PubMed Central

    Liu, Yu; Fang, Suqin; Chesson, Peter; He, Fangliang

    2015-01-01

    The overarching issue for understanding biodiversity maintenance is how fitness advantages accrue to a species as it becomes rare, as this is the defining feature of stable coexistence mechanisms. Without these fitness advantages, average fitness differences between species will lead to exclusion. However, empirical evidence is lacking, especially for forests, due to the difficulty of manipulating density on a large-enough scale. Here we took advantage of naturally occurring contrasts in abundance between sites of a subtropical tree species, Ormosia glaberrima, to demonstrate how low-density fitness advantages accrue by the Janzen–Connell mechanism. The results showed that soil pathogens suppressed seedling recruitment of O. glaberrima when it is abundant but had little effect on the seedlings when it is at low density due to the lack of pathogens. The difference in seedling survival between abundant and low-density sites demonstrates strong dependence of pathogenic effect on the abundance of host species. PMID:26632594

  14. Staphylococcal food poisoning and botulism

    PubMed Central

    Gilbert, R. J.

    1974-01-01

    Staphylococcal food poisoning and botulism are caused by the ingestion of food containing exotoxins. Outbreaks of both are still a problem in many countries. This paper attempts to summarize information relating to these illnesses, together with advice on how their incidence may be reduced, or better still prevented. PMID:4619651

  15. Association of coagulase-negative staphylococcal species, mammary quarter milk somatic cell count, and persistence of intramammary infection in dairy cattle.

    PubMed

    Fry, P R; Middleton, J R; Dufour, S; Perry, J; Scholl, D; Dohoo, I

    2014-01-01

    This study was conducted to evaluate the association between subclinical intramammary infection (IMI) with coagulase-negative staphylococci (CNS), mammary quarter milk somatic cell count (SCC), and persistence of IMI in dairy cattle. Convenience samples of CNS isolates harvested from milk samples of subclinically infected mammary quarters collected between 4 and 2wk before drying-off, between 2wk before drying-off and the day of drying-off, within 24h after calving, between 1 and 2wk after calving, and during lactation were evaluated. Isolates were obtained from the Canadian Bovine Mastitis Research Network culture bank and were identified to the species level using rpoB gene sequencing. Cow and quarter-level data were obtained from the Canadian Bovine Mastitis Research Network database and used for statistical analyses. In addition, for mammary quarters that had more than one isolation of the same CNS species at different time points, the isolates were evaluated using pulsed-field gel electrophoresis to identify persistent IMI. Milk SCC was compared between mammary quarters infected with different CNS species and to a cohort of uninfected mammary quarters. A total of 877 isolates from 643 mammary quarters of 555 cows on 89 Canadian dairy farms were identified to the species level. Twenty different species were identified, with Staphylococcus chromogenes being the most common species identified (48% of isolates), followed by Staphylococcus simulans (19%) and Staphylococcus xylosus (10%). Of the 20 species identified, only 9 species were found in persistently infected quarters. Milk SCC was significantly higher in the CNS-infected mammary quarters than in the uninfected control quarters for 8 of the 20 species studied. Also, mean SCC differed significantly between mammary quarters infected with different CNS species. Within a given species, a high degree of variability was noted in milk SCC. These data corroborate recent data from Europe with regard to the

  16. Chlamydial infections of fish: diverse pathogens and emerging causes of disease in aquaculture species.

    PubMed

    Stride, M C; Polkinghome, A; Nowak, B F

    2014-06-25

    Chlamydial infections of fish are emerging as an important cause of disease in new and established aquaculture industries. To date, epitheliocystis, a skin and gill disease associated with infection by these obligate intracellular pathogens, has been described in over 90 fish species, including hosts from marine and fresh water environments. Aided by advances in molecular detection and typing, recent years have seen an explosion in the description of these epitheliocystis-related chlamydial pathogens of fish, significantly broadening our knowledge of the genetic diversity of the order Chlamydiales. Remarkably, in most cases, it seems that each new piscine host studied has revealed the presence of a phylogenetically unique and novel chlamydial pathogen, providing researchers with a fascinating opportunity to understand the origin, evolution and adaptation of their traditional terrestrial chlamydial relatives. Despite the advances in this area, much still needs to be learnt about the epidemiology of chlamydial infections in fish if these pathogens are to be controlled in farmed environments. The lack of in vitro methods for culturing of chlamydial pathogens of fish is a major hindrance to this field. This review provides an update on our current knowledge of the taxonomy and diversity of chlamydial pathogens of fish, discusses the impact of these infections on the health, and highlights further areas of research required to understand the biology and epidemiology of this important emerging group of fish pathogens of aquaculture species.

  17. Chlamydial infections of fish: diverse pathogens and emerging causes of disease in aquaculture species.

    PubMed

    Stride, M C; Polkinghorne, A; Nowak, B F

    2014-05-14

    Chlamydial infections of fish are emerging as an important cause of disease in new and established aquaculture industries. To date, epitheliocystis, a skin and gill disease associated with infection by these obligate intracellular pathogens, has been described in over 90 fish species, including hosts from marine and fresh water environments. Aided by advances in molecular detection and typing, recent years have seen an explosion in the description of these epitheliocystis-related chlamydial pathogens of fish, significantly broadening our knowledge of the genetic diversity of the order Chlamydiales. Remarkably, in most cases, it seems that each new piscine host studied has revealed the presence of a phylogenetically unique and novel chlamydial pathogen, providing researchers with a fascinating opportunity to understand the origin, evolution and adaptation of their traditional terrestrial chlamydial relatives. Despite the advances in this area, much still needs to be learnt about the epidemiology of chlamydial infections in fish if these pathogens are to be controlled in farmed environments. The lack of in vitro methods for culturing of chlamydial pathogens of fish is a major hindrance to this field. This review provides an update on our current knowledge of the taxonomy and diversity of chlamydial pathogens of fish, discusses the impact of these infections on the health, and highlights further areas of research required to understand the biology and epidemiology of this important emerging group of fish pathogens of aquaculture species.

  18. Anatomical patterns of colonization of pets with staphylococcal species in homes of people with methicillin-resistant Staphylococcus aureus (MRSA) skin or soft tissue infection (SSTI).

    PubMed

    Iverson, S A; Brazil, A M; Ferguson, J M; Nelson, K; Lautenbach, E; Rankin, S C; Morris, D O; Davis, M F

    2015-03-23

    Methicillin-resistant strains of Staphylococcus aureus (MRSA), Staphylococcus pseudintermedius (MRSP), and other pathogenic staphylococci can cause infections in companion animals and humans. Identification of colonized animals is fundamental to research and practice needs, but harmonized methods have not yet been established. To establish the optimal anatomic site for the recovery of methicillin-resistant coagulase positive staphylococci (CPS), survey data and swabs were collected from 196 pets (dogs, cats, reptiles, birds, fish and pocket pets) that lived in households with an MRSA-infected person. Using broth-enrichment culture and PCR for speciation, S. aureus was identified in 27 of 179 (15%) pets sampled at baseline and 19 of 125 (15%) pets sampled at a three-month follow-up home visit. S. pseudintermedius was isolated from 33 of 179 (18%) pets sampled at baseline and 21 of 125 (17%) of pets sampled at follow-up. The baseline MRSA and MRSP prevalence was 8% and 1% respectively from 145 mammalian pets. The follow-up MRSA and MRSP prevalence was 7% and <1% respectively from 95 mammalian pets. The mouth was the most sensitive single site sampled for isolation of S. aureus and S. pseudintermedius in mammals. In a subset of pets, from which all available isolates were identified, dual carriage of S. aureus and S. pseudintermedius was 22% at baseline and 11% at follow-up. These results identify the mouth as the most sensitive site to screen for pathogenic staphylococci and suggest that it should be included in sampling protocols.

  19. Herbivore and Fungal Pathogen Exclusion Affects the Seed Production of Four Common Grassland Species

    PubMed Central

    Dickson, Timothy L.; Mitchell, Charles E.

    2010-01-01

    Insect herbivores and fungal pathogens can independently affect plant fitness, and may have interactive effects. However, few studies have experimentally quantified the joint effects of insects and fungal pathogens on seed production in non-agricultural populations. We examined the factorial effects of insect herbivore exclusion (via insecticide) and fungal pathogen exclusion (via fungicide) on the population-level seed production of four common graminoid species (Andropogon gerardii, Schizachyrium scoparium, Poa pratensis, and Carex siccata) over two growing seasons in Minnesota, USA. We detected no interactive effects of herbivores and pathogens on seed production. However, the seed production of all four species was affected by either insecticide or fungicide in at least one year of the study. Insecticide consistently doubled the seed production of the historically most common species in the North American tallgrass prairie, A. gerardii (big bluestem). This is the first report of insect removal increasing seed production in this species. Insecticide increased A. gerardii number of seeds per seed head in one year, and mass per seed in both years, suggesting that consumption of flowers and seed embryos contributed to the effect on seed production. One of the primary insect species consuming A. gerardii flowers and seed embryos was likely the Cecidomyiid midge, Contarinia wattsi. Effects on all other plant species varied among years. Herbivores and pathogens likely reduce the dispersal and colonization ability of plants when they reduce seed output. Therefore, impacts on seed production of competitive dominant species may help to explain their relatively poor colonization abilities. Reduced seed output by dominant graminoids may thereby promote coexistence with subdominant species through competition-colonization tradeoffs. PMID:20711408

  20. Staphylococcal Blood Stream Infections: Epidemiology, Resistance Pattern and Outcome at a Level 1 Indian Trauma Care Center

    PubMed Central

    Tak, Vibhor; Mathur, Purva; Lalwani, Sanjeev; Misra, Mahesh Chandra

    2013-01-01

    Purpose: Blood stream infection (BSI)/bacteremia is a potentially life threatening infection and are associated with a high crude mortality. Coagulase negative Staphylococcus (CONS) and Staphylococcus aureus are the most commonly isolated gram positive bacteria from blood culture samples. While S. aureus is a known pathogen causing BSIs, CONS are considered to be common contaminants of blood culture. Of late many studies have challenged this traditional viewpoint. The aim of this study was to determine the epidemiology and significance of Staphylococcus aureus and CONS bacteremia, their resistance patterns and associated mortality in critically ill trauma patients admitted to a level 1 trauma center. Materials and Methods: The study was conducted from January 2009 to June 2011. All patients from whose blood samples yielded a S. aureus or CONS on culture were included in this study. A detailed history was obtained and follow-up of the patients was done. The isolates of Staphylococci were identified to species level. Antibiotic susceptibility was performed by the disc diffusion method and VITEK-2 system. Results: During this 30 month period, total of 10,509 blood samples were received from 2,938 patients. A total of 1,961 samples taken from 905 patients were positive for one or more pathogens. S. aureus/CONS were isolated from 469 samples from 374 patients. Crude mortality amongst the patients having Staphylococcal BSI was 25% (94/374). Conclusion: Staphylococcal blood stream infections are a leading cause of morbidity and mortality. PMID:24014969

  1. Saprophytic and Potentially Pathogenic Fusarium Species from Peat Soil in Perak and Pahang.

    PubMed

    Karim, Nurul Farah Abdul; Mohd, Masratulhawa; Nor, Nik Mohd Izham Mohd; Zakaria, Latiffah

    2016-02-01

    Isolates of Fusarium were discovered in peat soil samples collected from peat swamp forest, waterlogged peat soil, and peat soil from oil palm plantations. Morphological characteristics were used to tentatively identify the isolates, and species confirmation was based on the sequence of translation elongation factor-1α (TEF-1α) and phylogenetic analysis. Based on the closest match of Basic Local Alignment Search Tool (BLAST) searches against the GenBank and Fusarium-ID databases, five Fusarium species were identified, namely F. oxysporum (60%), F. solani (23%), F. proliferatum (14%), F. semitectum (1%), and F. verticillioides (1%). From a neighbour-joining tree of combined TEF-1α and β-tubulin sequences, isolates from the same species were clustered in the same clade, though intraspecies variations were observed from the phylogenetic analysis. The Fusarium species isolated in the present study are soil inhabitants and are widely distributed worldwide. These species can act as saprophytes and decomposers as well as plant pathogens. The presence of Fusarium species in peat soils suggested that peat soils could be a reservoir of plant pathogens, as well-known plant pathogenic species such F. oxysporum, F. solani, F. proliferatum, and F. verticillioides were identified. The results of the present study provide knowledge on the survival and distribution of Fusarium species.

  2. Saprophytic and Potentially Pathogenic Fusarium Species from Peat Soil in Perak and Pahang

    PubMed Central

    Karim, Nurul Farah Abdul; Mohd, Masratulhawa; Nor, Nik Mohd Izham Mohd; Zakaria, Latiffah

    2016-01-01

    Isolates of Fusarium were discovered in peat soil samples collected from peat swamp forest, waterlogged peat soil, and peat soil from oil palm plantations. Morphological characteristics were used to tentatively identify the isolates, and species confirmation was based on the sequence of translation elongation factor-1α (TEF-1α) and phylogenetic analysis. Based on the closest match of Basic Local Alignment Search Tool (BLAST) searches against the GenBank and Fusarium-ID databases, five Fusarium species were identified, namely F. oxysporum (60%), F. solani (23%), F. proliferatum (14%), F. semitectum (1%), and F. verticillioides (1%). From a neighbour-joining tree of combined TEF-1α and β-tubulin sequences, isolates from the same species were clustered in the same clade, though intraspecies variations were observed from the phylogenetic analysis. The Fusarium species isolated in the present study are soil inhabitants and are widely distributed worldwide. These species can act as saprophytes and decomposers as well as plant pathogens. The presence of Fusarium species in peat soils suggested that peat soils could be a reservoir of plant pathogens, as well-known plant pathogenic species such F. oxysporum, F. solani, F. proliferatum, and F. verticillioides were identified. The results of the present study provide knowledge on the survival and distribution of Fusarium species. PMID:27019679

  3. PCR-restriction fragment length polymorphism analysis using groEL gene to differentiate pathogenic Vibrio species.

    PubMed

    Hossain, Muhammad Tofazzal; Kim, Yu-Ri; Kong, In-Soo

    2014-01-01

    Important pathogenic Vibrio species were differentiated by PCR-restriction fragment length polymorphism analysis. A 1117-bp groEL gene product was amplified using universal primers and digested using the restriction enzymes NruI or XbaI, revealing unique digestion patterns for each of the 10 Vibrio species, of which 7 were pathogenic in humans, along with 2 other species pathogenic in fish.

  4. Genomic Characterization Reveals Insights Into Patulin Biosynthesis and Pathogenicity in Penicillium Species.

    PubMed

    Li, Boqiang; Zong, Yuanyuan; Du, Zhenglin; Chen, Yong; Zhang, Zhanquan; Qin, Guozheng; Zhao, Wenming; Tian, Shiping

    2015-06-01

    Penicillium species are fungal pathogens that infect crop plants worldwide. P. expansum differs from P. italicum and P. digitatum, all major postharvest pathogens of pome and citrus, in that the former is able to produce the mycotoxin patulin and has a broader host range. The molecular basis of host-specificity of fungal pathogens has now become the focus of recent research. The present report provides the whole genome sequence of P. expansum (33.52 Mb) and P. italicum (28.99 Mb) and identifies differences in genome structure, important pathogenic characters, and secondary metabolite (SM) gene clusters in Penicillium species. We identified a total of 55 gene clusters potentially related to secondary metabolism, including a cluster of 15 genes (named PePatA to PePatO), that may be involved in patulin biosynthesis in P. expansum. Functional studies confirmed that PePatL and PePatK play crucial roles in the biosynthesis of patulin and that patulin production is not related to virulence of P. expansum. Collectively, P. expansum contains more pathogenic genes and SM gene clusters, in particular, an intact patulin cluster, than P. italicum or P. digitatum. These findings provide important information relevant to understanding the molecular network of patulin biosynthesis and mechanisms of host-specificity in Penicillium species.

  5. Forest species diversity reduces disease risk in a generalist plant pathogen invasion

    USGS Publications Warehouse

    Haas, Sarah E.; Hooten, Mevin B.; Rizzo, David M.; Meentemeyer, Ross K.

    2011-01-01

    Empirical evidence suggests that biodiversity loss can increase disease transmission, yet our understanding of the 'diversity-disease hypothesis' for generalist pathogens in natural ecosystems is limited. We used a landscape epidemiological approach to examine two scenarios regarding diversity effects on the emerging plant pathogen Phytophthora ramorum across a broad, heterogeneous ecoregion: (1) an amplification effect exists where disease risk is greater in areas with higher plant diversity due to the pathogen's wide host range, or (2) a dilution effect where risk is reduced with increasing diversity due to lower competency of alternative hosts. We found evidence for pathogen dilution, whereby disease risk was lower in sites with higher species diversity, after accounting for potentially confounding effects of host density and landscape heterogeneity. Our results suggest that although nearly all plants in the ecosystem are hosts, alternative hosts may dilute disease transmission by competent hosts, thereby buffering forest health from infectious disease.

  6. Role of intraspecies recombination in the spread of pathogenicity islands within the Escherichia coli species.

    PubMed

    Schubert, Sören; Darlu, Pierre; Clermont, Olivier; Wieser, Andreas; Magistro, Giuseppe; Hoffmann, Christiane; Weinert, Kirsten; Tenaillon, Olivier; Matic, Ivan; Denamur, Erick

    2009-01-01

    Horizontal gene transfer is a key step in the evolution of bacterial pathogens. Besides phages and plasmids, pathogenicity islands (PAIs) are subjected to horizontal transfer. The transfer mechanisms of PAIs within a certain bacterial species or between different species are still not well understood. This study is focused on the High-Pathogenicity Island (HPI), which is a PAI widely spread among extraintestinal pathogenic Escherichia coli and serves as a model for horizontal transfer of PAIs in general. We applied a phylogenetic approach using multilocus sequence typing on HPI-positive and -negative natural E. coli isolates representative of the species diversity to infer the mechanism of horizontal HPI transfer within the E. coli species. In each strain, the partial nucleotide sequences of 6 HPI-encoded genes and 6 housekeeping genes of the genomic backbone, as well as DNA fragments immediately upstream and downstream of the HPI were compared. This revealed that the HPI is not solely vertically transmitted, but that recombination of large DNA fragments beyond the HPI plays a major role in the spread of the HPI within E. coli species. In support of the results of the phylogenetic analyses, we experimentally demonstrated that HPI can be transferred between different E. coli strains by F-plasmid mediated mobilization. Sequencing of the chromosomal DNA regions immediately upstream and downstream of the HPI in the recipient strain indicated that the HPI was transferred and integrated together with HPI-flanking DNA regions of the donor strain. The results of this study demonstrate for the first time that conjugative transfer and homologous DNA recombination play a major role in horizontal transfer of a pathogenicity island within the species E. coli.

  7. Populations of a Susceptible Amphibian Species Can Grow despite the Presence of a Pathogenic Chytrid Fungus

    PubMed Central

    Tobler, Ursina; Borgula, Adrian; Schmidt, Benedikt R.

    2012-01-01

    Disease can be an important driver of host population dynamics and epizootics can cause severe host population declines. Batrachochytrium dendrobatidis (Bd), the pathogen causing amphibian chytridiomycosis, may occur epizootically or enzootically and can harm amphibian populations in many ways. While effects of Bd epizootics are well documented, the effects of enzootic Bd have rarely been described. We used a state-space model that accounts for observation error to test whether population trends of a species highly susceptible to Bd, the midwife toad Alytes obstetricans, are negatively affected by the enzootic presence of the pathogen. Unexpectedly, Bd had no negative effect on population growth rates from 2002–2008. This suggests that negative effects of disease on individuals do not necessarily translate into negative effects at the population level. Populations of amphibian species that are susceptible to the emerging disease chytridiomycosis can persist despite the enzootic presence of the pathogen under current environmental conditions. PMID:22496836

  8. Serologic survey for cross-species pathogens in urban coyotes (Canis latrans), Colorado, USA.

    PubMed

    Malmlov, Ashley; Breck, Stewart; Fry, Tricia; Duncan, Colleen

    2014-10-01

    Abstract As coyotes (Canis latrans) adapt to living in urban environments, the opportunity for cross-species transmission of pathogens may increase. We investigated the prevalence of antibodies to pathogens that are either zoonotic or affect multiple animal species in urban coyotes in the Denver metropolitan area, Colorado, USA, in 2012. We assayed for antibodies to canine parvovirus-2, canine distemper virus, rabies virus, Toxoplasma gondii, Yersinia pestis, and serotypes of Leptospira interrogans. Overall, 84% of the animals had antibodies to canine parvovirus-2, 44% for canine distemper virus, 20% for T. gondii (IgG), 28% for Y. pestis, and 4% for L. interrogans serotype Grippotyphosa. No neutralizing antibodies were detected to rabies virus, T. gondii (IgM), or L. interrogans serotypes other than Grippotyphosa. With 88% of animals exposed to at least one pathogen, our results suggest that coyotes may serve as important reservoirs and sentinels for etiologic agents.

  9. Serologic survey for cross-species pathogens in urban coyotes (Canis latrans), Colorado, USA.

    PubMed

    Malmlov, Ashley; Breck, Stewart; Fry, Tricia; Duncan, Colleen

    2014-10-01

    Abstract As coyotes (Canis latrans) adapt to living in urban environments, the opportunity for cross-species transmission of pathogens may increase. We investigated the prevalence of antibodies to pathogens that are either zoonotic or affect multiple animal species in urban coyotes in the Denver metropolitan area, Colorado, USA, in 2012. We assayed for antibodies to canine parvovirus-2, canine distemper virus, rabies virus, Toxoplasma gondii, Yersinia pestis, and serotypes of Leptospira interrogans. Overall, 84% of the animals had antibodies to canine parvovirus-2, 44% for canine distemper virus, 20% for T. gondii (IgG), 28% for Y. pestis, and 4% for L. interrogans serotype Grippotyphosa. No neutralizing antibodies were detected to rabies virus, T. gondii (IgM), or L. interrogans serotypes other than Grippotyphosa. With 88% of animals exposed to at least one pathogen, our results suggest that coyotes may serve as important reservoirs and sentinels for etiologic agents. PMID:25121408

  10. Cadophora species as trunk pathogens and wood-infecting fungi of grapevine in North America

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cadophora species, in particular Cadophora luteo-olivacea, are reported from grapevine (Vitis vinifera L.) in California, South Africa, Spain, Uruguay, and Canada. Frequent isolation from vines co-infected with the Esca pathogens (Togninia minima, Phaeomoniella chlamydospora), and confirmation of it...

  11. Evolutionary study of Yersinia genomes deciphers emergence of human pathogenic species

    PubMed Central

    Tan, Shi Yang; Tan, Irene Kit Ping; Tan, Mui Fern; Dutta, Avirup; Choo, Siew Woh

    2016-01-01

    On record, there are 17 species in the Yersinia genus, of which three are known to be pathogenic to human. While the chromosomal and pYV (or pCD1) plasmid-borne virulence genes as well as pathogenesis of these three species are well studied, their genomic evolution is poorly understood. Our study aims to predict the key evolutionary events that led to the emergence of pathogenic Yersinia species by analyzing gene gain-and-loss, virulence genes, and “Clustered regularly-interspaced short palindromic repeats”. Our results suggest that the most recent ancestor shared by the human pathogenic Yersinia was most probably an environmental species that had adapted to the human body. This might have led to ecological specialization that diverged Yersinia into ecotypes and distinct lineages based on differential gene gain-and-loss in different niches. Our data also suggest that Y. pseudotuberculosis group might be the donor of the ail virulence gene to Y. enterocolitica. Hence, we postulate that evolution of human pathogenic Yersinia might not be totally in parallel, but instead, there were lateral gene transfer events. Furthermore, the presence of virulence genes seems to be important for the positive selection of virulence plasmid. Our studies provide better insights into the evolutionary biology of these bacteria. PMID:27796355

  12. The making of a new pathogen: Insights from comparative population genomics of the domesticated wheat pathogen Mycosphaerella graminicola and its wild sister species

    PubMed Central

    Stukenbrock, Eva H.; Bataillon, Thomas; Dutheil, Julien Y.; Hansen, Troels T.; Li, Ruiqiang; Zala, Marcello; McDonald, Bruce A.; Wang, Jun; Schierup, Mikkel H.

    2011-01-01

    The fungus Mycosphaerella graminicola emerged as a new pathogen of cultivated wheat during its domestication ∼11,000 yr ago. We assembled 12 high-quality full genome sequences to investigate the genetic footprints of selection in this wheat pathogen and closely related sister species that infect wild grasses. We demonstrate a strong effect of natural selection in shaping the pathogen genomes with only ∼3% of nonsynonymous mutations being effectively neutral. Forty percent of all fixed nonsynonymous substitutions, on the other hand, are driven by positive selection. Adaptive evolution has affected M. graminicola to the highest extent, consistent with recent host specialization. Positive selection has prominently altered genes encoding secreted proteins and putative pathogen effectors supporting the premise that molecular host–pathogen interaction is a strong driver of pathogen evolution. Recent divergence between pathogen sister species is attested by the high degree of incomplete lineage sorting (ILS) in their genomes. We exploit ILS to generate a genetic map of the species without any crossing data, document recent times of species divergence relative to genome divergence, and show that gene-rich regions or regions with low recombination experience stronger effects of natural selection on neutral diversity. Emergence of a new agricultural host selected a highly specialized and fast-evolving pathogen with unique evolutionary patterns compared with its wild relatives. The strong impact of natural selection, we document, is at odds with the small effective population sizes estimated and suggest that population sizes were historically large but likely unstable. PMID:21994252

  13. Development of a DNA-based microarray for the detection of zoonotic pathogens in rodent species.

    PubMed

    Giles, Timothy; Yon, Lisa; Hannant, Duncan; Barrow, Paul; Abu-Median, Abu-Bakr

    2015-12-01

    The demand for diagnostic tools that allow simultaneous screening of samples for multiple pathogens is increasing because they overcome the limitations of other methods, which can only screen for a single or a few pathogens at a time. Microarrays offer the advantages of being capable to test a large number of samples simultaneously, screening for multiple pathogen types per sample and having comparable sensitivity to existing methods such as PCR. Array design is often considered the most important process in any microarray experiment and can be the deciding factor in the success of a study. There are currently no microarrays for simultaneous detection of rodent-borne pathogens. The aim of this report is to explicate the design, development and evaluation of a microarray platform for use as a screening tool that combines ease of use and rapid identification of a number of rodent-borne pathogens of zoonotic importance. Nucleic acid was amplified by multiplex biotinylation PCR prior to hybridisation onto microarrays. The array sensitivity was comparable to standard PCR, though less sensitive than real-time PCR. The array presented here is a prototype microarray identification system for zoonotic pathogens that can infect rodent species. PMID:26188129

  14. Development of a DNA-based microarray for the detection of zoonotic pathogens in rodent species.

    PubMed

    Giles, Timothy; Yon, Lisa; Hannant, Duncan; Barrow, Paul; Abu-Median, Abu-Bakr

    2015-12-01

    The demand for diagnostic tools that allow simultaneous screening of samples for multiple pathogens is increasing because they overcome the limitations of other methods, which can only screen for a single or a few pathogens at a time. Microarrays offer the advantages of being capable to test a large number of samples simultaneously, screening for multiple pathogen types per sample and having comparable sensitivity to existing methods such as PCR. Array design is often considered the most important process in any microarray experiment and can be the deciding factor in the success of a study. There are currently no microarrays for simultaneous detection of rodent-borne pathogens. The aim of this report is to explicate the design, development and evaluation of a microarray platform for use as a screening tool that combines ease of use and rapid identification of a number of rodent-borne pathogens of zoonotic importance. Nucleic acid was amplified by multiplex biotinylation PCR prior to hybridisation onto microarrays. The array sensitivity was comparable to standard PCR, though less sensitive than real-time PCR. The array presented here is a prototype microarray identification system for zoonotic pathogens that can infect rodent species.

  15. Antibodies to PhnD Inhibit Staphylococcal Biofilms

    PubMed Central

    Lam, Hubert; Kesselly, Augustus; Stegalkina, Svetlana; Kleanthous, Harry

    2014-01-01

    Biofilm formation on central lines or peripheral catheters is a serious threat to patient well-being. Contaminated vascular devices can act as a nidus for bloodstream infection and systemic pathogen dissemination. Staphylococcal biofilms are the most common cause of central-line-associated bloodstream infections, and antibiotic resistance makes them difficult to treat. As an alternative to antibiotic intervention, we sought to identify anti-staphylococcal biofilm targets for the development of a vaccine or antibody prophylactic. A screening strategy was devised using a microfluidic system to test antibody-mediated biofilm inhibition under biologically relevant conditions of shear flow. Affinity-purified polyclonal antibodies to target antigen PhnD inhibited both Staphylococcus epidermidis and S. aureus biofilms. PhnD-specific antibodies blocked biofilm development at the initial attachment and aggregation stages, and deletion of phnD inhibited normal biofilm formation. We further adapted our microfluidic biofilm system to monitor the interaction of human neutrophils with staphylococcal biofilms and demonstrated that PhnD-specific antibodies also serve as opsonins to enhance neutrophil binding, motility, and biofilm engulfment. These data support the identification of PhnD as a lead target for biofilm intervention strategies performed either by vaccination or through passive administration of antibodies. PMID:24958708

  16. Lysostaphin: A Staphylococcal Bacteriolysin with Potential Clinical Applications

    PubMed Central

    Bastos, Maria do Carmo de Freire; Coutinho, Bruna Gonçalves; Coelho, Marcus Lívio Varella

    2010-01-01

    Lysostaphin is an antimicrobial agent belonging to a major class of antimicrobial peptides and proteins known as the bacteriocins. Bacteriocins are bacterial antimicrobial peptides which generally exhibit bactericidal activity against other bacteria. Bacteriocin production is a self-protection mechanism that helps the microorganisms to survive in their natural habitats. Bacteriocins are currently distributed into three main classes. Staphylococcins are bacteriocins produced by staphylococci, which are Gram-positive bacteria of medical and veterinary importance. Lysostaphin is the only class III staphylococcin described so far. It exhibits a high degree of antistaphylococcal bacteriolytic activity, being inactive against bacteria of all other genera. Infections caused by staphylococci continue to be a problem worldwide not only in healthcare environments but also in the community, requiring effective measures for controlling their spread. Since lysostaphin kills human and animal staphylococcal pathogens, it has potential biotechnological applications in the treatment of staphylococcal infections. In vitro and in vivo studies performed with lysostaphin have shown that this staphylococcin has potential to be used, solely or in combination with other antibacterial agents, to prevent or treat bacterial staphylococcal infectious diseases. PMID:27713293

  17. Antibodies to some pathogenic agents in free-living wild species in Tanzania.

    PubMed

    Hamblin, C; Anderson, E C; Jago, M; Mlengeya, T; Hipji, K

    1990-12-01

    A total of 535 sera from eight species of wildlife were collected from different game areas in Tanzania between 1987 and 1989. These sera were tested for antibodies against foot-and-mouth disease, bovine herpes virus types 1 and 2, lumpy skin disease, bovine viral diarrhoea, Akabane, bovine ephemeral fever, bluetongue, enzootic bovine leucosis, African horse sickness and African swine fever viruses and Brucella abortus based on the expected species susceptibility. Sera from buffalo Syncerus caffer, wildebeest Connochaetes taurinus and topi Damaliscus korrigum contained antibodies against the majority of the pathogens tested. Antibodies to fewer pathogens were detected in sera from the other species. No antibodies to lumpy skin disease virus were detected in any of the sera examined. African horse sickness antibodies were detected in sera from Zebra and African swine fever antibodies were detected in wart hog. The occurrence of antibodies to these agents suggests that wild species act as reservoirs of infection for some of these pathogens. However, until the susceptibility of individual species is proven by isolation of the aetiological agents their role must remain speculative. PMID:2123458

  18. Integrative conjugative elements are widespread in field isolates of Mycoplasma species pathogenic for ruminants.

    PubMed

    Tardy, Florence; Mick, Virginie; Dordet-Frisoni, Emilie; Marenda, Marc Serge; Sirand-Pugnet, Pascal; Blanchard, Alain; Citti, Christine

    2015-03-01

    Comparative genomics have revealed massive horizontal gene transfer (HGT) between Mycoplasma species sharing common ruminant hosts. Further results pointed toward an integrative conjugative element (ICE) as an important contributor of HGT in the small-ruminant-pathogen Mycoplasma agalactiae. To estimate the prevalence of ICEs in ruminant mycoplasmas, we surveyed their occurrence in a collection of 166 field strains representing 4 (sub)species that are recognized as major pathogens. Based on available sequenced genomes, we first defined the conserved, minimal ICE backbone as composed of 4 coding sequences (CDSs) that are evenly distributed and predicted to be essential for ICE chromosomal integration-excision and horizontal transfer. Screening of the strain collection revealed that these 4 CDSs are well represented in ruminant Mycoplasma species, suggesting widespread occurrence of ICEs. Yet their prevalence varies within and among species, with no correlation found with the individual strain history. Extrachromosomal ICE forms were also often detected, suggesting that ICEs are able to circularize in all species, a first and essential step in ICE horizontal transfer. Examination of the junction of the circular forms and comparative sequence analysis of conserved CDSs clearly pointed toward two types of ICE, the hominis and spiroplasma types, most likely differing in their mechanism of excision-integration. Overall, our data indicate the occurrence and maintenance of functional ICEs in a large number of field isolates of ruminant mycoplasmas. These may contribute to genome plasticity and gene exchanges and, presumably, to the emergence of diverse genotypes within pathogenic mycoplasmas of veterinary importance.

  19. Mechanisms of Disease: Host-Pathogen Interactions between Burkholderia Species and Lung Epithelial Cells

    PubMed Central

    David, Jonathan; Bell, Rachel E.; Clark, Graeme C.

    2015-01-01

    Members of the Burkholderia species can cause a range of severe, often fatal, respiratory diseases. A variety of in vitro models of infection have been developed in an attempt to elucidate the mechanism by which Burkholderia spp. gain entry to and interact with the body. The majority of studies have tended to focus on the interaction of bacteria with phagocytic cells with a paucity of information available with regard to the lung epithelium. However, the lung epithelium is becoming more widely recognized as an important player in innate immunity and the early response to infections. Here we review the complex relationship between Burkholderia species and epithelial cells with an emphasis on the most pathogenic species, Burkholderia pseudomallei and Burkholderia mallei. The current gaps in knowledge in our understanding are highlighted along with the epithelial host-pathogen interactions that offer potential opportunities for therapeutic intervention. PMID:26636042

  20. Comparative Genomic Analysis Reveals a Possible Novel Non-Tuberculous Mycobacterium Species with High Pathogenic Potential.

    PubMed

    Choo, Siew Woh; Dutta, Avirup; Wong, Guat Jah; Wee, Wei Yee; Ang, Mia Yang; Siow, Cheuk Chuen

    2016-01-01

    Mycobacteria have been reported to cause a wide range of human diseases. We present the first whole-genome study of a Non-Tuberculous Mycobacterium, Mycobacterium sp. UM_CSW (referred to hereafter as UM_CSW), isolated from a patient diagnosed with bronchiectasis. Our data suggest that this clinical isolate is likely a novel mycobacterial species, supported by clear evidence from molecular phylogenetic, comparative genomic, ANI and AAI analyses. UM_CSW is closely related to the Mycobacterium avium complex. While it has characteristic features of an environmental bacterium, it also shows a high pathogenic potential with the presence of a wide variety of putative genes related to bacterial virulence and shares very similar pathogenomic profiles with the known pathogenic mycobacterial species. Thus, we conclude that this possible novel Mycobacterium species should be tightly monitored for its possible causative role in human infections. PMID:27035710

  1. Comparative Genomic Analysis Reveals a Possible Novel Non-Tuberculous Mycobacterium Species with High Pathogenic Potential

    PubMed Central

    Choo, Siew Woh; Dutta, Avirup; Wong, Guat Jah; Wee, Wei Yee; Ang, Mia Yang; Siow, Cheuk Chuen

    2016-01-01

    Mycobacteria have been reported to cause a wide range of human diseases. We present the first whole-genome study of a Non-Tuberculous Mycobacterium, Mycobacterium sp. UM_CSW (referred to hereafter as UM_CSW), isolated from a patient diagnosed with bronchiectasis. Our data suggest that this clinical isolate is likely a novel mycobacterial species, supported by clear evidence from molecular phylogenetic, comparative genomic, ANI and AAI analyses. UM_CSW is closely related to the Mycobacterium avium complex. While it has characteristic features of an environmental bacterium, it also shows a high pathogenic potential with the presence of a wide variety of putative genes related to bacterial virulence and shares very similar pathogenomic profiles with the known pathogenic mycobacterial species. Thus, we conclude that this possible novel Mycobacterium species should be tightly monitored for its possible causative role in human infections. PMID:27035710

  2. Antigenic relationship between the animal and human pathogen Pythium insidiosum and nonpathogenic Pythium species.

    PubMed Central

    Mendoza, L; Kaufman, L; Standard, P

    1987-01-01

    Identification of the newly named pathogenic oomycete Pythium insidiosum and its differentiation from other Pythium species by morphologic criteria alone can be difficult and time-consuming. Antigenic analysis by fluorescent-antibody and immunodiffusion precipitin techniques demonstrated that the P. insidiosum isolates that cause pythiosis in dogs, horses, and humans are identical and that they were distinguishable from other Pythium species by these means. The immunologic data agreed with the morphologic data. This indicated that the animal and human isolates belonged to a single species, P. insidiosum. Fluorescent-antibody and immunodiffusion reagents were developed for the specific identification of P. insidiosum. PMID:3121666

  3. Phenol-soluble modulins, hellhounds from the staphylococcal virulence-factor pandemonium.

    PubMed

    Tsompanidou, Eleni; Denham, Emma L; van Dijl, Jan Maarten

    2013-07-01

    Phenol-soluble modulins are secreted peptides with multiple functions in Staphylococcus aureus pathogenesis and spreading. Recent studies by Otto and coworkers show that these hellhounds of the staphylococcal virulence-factor pandemonium are unleashed through an essential ABC transporter, which represents an exciting new target for stopping the spread of this important pathogen.

  4. Inhibition of Biological Activity of Staphylococcal Enterotoxin A (SEA) by Apple Juice and Apple Polyphenols

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The foodborne pathogen Staphylococcus aureus produces the virulent staphylococcal entertoxin A (SEA), a single-chain protein that consists of 233 amino acid residues with a molecular weight of 27 078 Da. SEA is a superantigen that is reported to contribute to animal (mastitis) and human (emesis, dia...

  5. Paramecium species ingest and kill the cells of the human pathogenic fungus Cryptococcus neoformans

    PubMed Central

    FRAGER, SHALOM Z.; CHRISMAN, CARA J.; SHAKKED, RACHEL; CASADEVALL, ARTURO

    2015-01-01

    A fundamental question in the field of medical mycology is the origin of virulence in those fungal pathogens acquired directly from the environment. In recent years, it was proposed that the virulence of certain environmental animal-pathogenic microbes, such as Cryptococcus neoformans , originated from selection pressures caused by species-specific predation. In this study, we analyzed the interaction of C. neoformans with three Paramecium spp., all of which are ciliated mobile protists. In contrast to the interaction with amoebae, some Paramecium spp. rapidly ingested C. neoformans and killed the fungus. This study establishes yet another type of protist-fungal interaction supporting the notion that animal-pathogenic fungi in the environment are under constant selection by predation. PMID:20233022

  6. Paramecium species ingest and kill the cells of the human pathogenic fungus Cryptococcus neoformans.

    PubMed

    Frager, Shalom Z; Chrisman, Cara J; Shakked, Rachel; Casadevall, Arturo

    2010-08-01

    A fundamental question in the field of medical mycology is the origin of virulence in those fungal pathogens acquired directly from the environment. In recent years, it was proposed that the virulence of certain environmental animal-pathogenic microbes, such as Cryptococcus neoformans, originated from selection pressures caused by species-specific predation. In this study, we analyzed the interaction of C. neoformans with three Paramecium spp., all of which are ciliated mobile protists. In contrast to the interaction with amoebae, some Paramecium spp. rapidly ingested C. neoformans and killed the fungus. This study establishes yet another type of protist-fungal interaction supporting the notion that animal-pathogenic fungi in the environment are under constant selection by predation.

  7. Prevalence of potentially pathogenic Vibrio species in the seafood marketed in Malaysia.

    PubMed

    Elhadi, Nasreldin; Radu, Son; Chen, Chien-Hsien; Nishibuchi, Mitsuaki

    2004-07-01

    Seafood samples obtained in seafood markets and supermarkets at 11 sites selected from four states in Malaysia were examined for the presence of nine potentially pathogenic species from the genus Vibrio between July 1998 and June 1999. We examined 768 sample sets that included shrimp, squid, crab, cockles, and mussels. We extensively examined shrimp samples from Selangor State to determine seasonal variation of Vibrio populations. Eight potentially pathogenic Vibrio species were detected, with overall incidence in the samples at 4.6% for V. cholerae, 4.7% for V. parahaemolyticus, 6.0% for V. vulnificus, 11% for V. alginolyticus, 9.9% for V. metschnikovii, 1.3% for V. mimicus, 13% for V. damsela, 7.6% for V. fluvialis, and 52% for a combined population of all of the above. As many as eight Vibrio species were detected in shrimp and only four in squid and peel mussels. The overall percent incidence of any of the eight vibrios was highest (82%) in cockles (Anadara granosa) among the seafoods examined and was highest (100%) in Kuching, Sarawak State, and lowest (25%) in Penang, Pulau Penang State, among the sampling sites. Of 97 strains of V. cholerae isolated, one strain belonged to the O1 serotype and 14 to the O139 serotype. The results indicate that the various seafood markets in Malaysia are contaminated with potentially pathogenic Vibrio species regardless of the season and suggest that there is a need for adequate consumer protection measures.

  8. Brucellosis, botflies, and brainworms: the impact of edge habitats on pathogen transmission and species extinction.

    PubMed

    Cantrell, R S; Cosner, C; Fagan, W F

    2001-02-01

    Ecological interactions between species that prefer different habitat types but come into contact in edge regions at the interfaces between habitat types are modeled via reaction-diffusion systems. The primary sort of interaction described by the models is competition mediated by pathogen transmission. The models are somewhat novel because the spatial domains for the variables describing the population densities of the interacting species overlap but do not coincide. Conditions implying coexistence of the two species or the extinction of one species are derived. The conditions involve the principal eigenvalues of elliptic operators arising from linearizations of the model system around equilibria with only one species present. The conditions for persistence or extinction are made explicit in terms of the parameters of the system and the geometry of the underlying spatial domains via estimates of the principal eigenvalues. The implications of the models with respect to conservation and refuge design are discussed.

  9. Species or Genotypes? Reassessment of Four Recently Described Species of the Ceratocystis Wilt Pathogen, Ceratocystis fimbriata, on Mangifera indica.

    PubMed

    Oliveira, Leonardo S S; Harrington, Thomas C; Ferreira, Maria A; Damacena, Michelle B; Al-Sadi, Abdullah M; Al-Mahmooli, Issa H S; Alfenas, Acelino C

    2015-09-01

    Ceratocystis wilt is among the most important diseases on mango (Mangifera indica) in Brazil, Oman, and Pakistan. The causal agent was originally identified in Brazil as Ceratocystis fimbriata, which is considered by some as a complex of many cryptic species, and four new species on mango trees were distinguished from C. fimbriata based on variation in internal transcribed spacer sequences. In the present study, phylogenetic analyses using DNA sequences of mating type genes, TEF-1α, and β-tubulin failed to identify lineages corresponding to the four new species names. Further, mating experiments found that the mango isolates representing the new species were interfertile with each other and a tester strain from sweet potato (Ipomoea batatas), on which the name C. fimbriata is based, and there was little morphological variation among the mango isolates. Microsatellite markers found substantial differentiation among mango isolates at the regional and population levels, but certain microsatellite genotypes were commonly found in multiple populations, suggesting that these genotypes had been disseminated in infected nursery stock. The most common microsatellite genotypes corresponded to the four recently named species (C. manginecans, C. acaciivora, C. mangicola, and C. mangivora), which are considered synonyms of C. fimbriata. This study points to the potential problems of naming new species based on introduced genotypes of a pathogen, the value of an understanding of natural variation within and among populations, and the importance of phenotype in delimiting species. PMID:25822187

  10. Species or Genotypes? Reassessment of Four Recently Described Species of the Ceratocystis Wilt Pathogen, Ceratocystis fimbriata, on Mangifera indica.

    PubMed

    Oliveira, Leonardo S S; Harrington, Thomas C; Ferreira, Maria A; Damacena, Michelle B; Al-Sadi, Abdullah M; Al-Mahmooli, Issa H S; Alfenas, Acelino C

    2015-09-01

    Ceratocystis wilt is among the most important diseases on mango (Mangifera indica) in Brazil, Oman, and Pakistan. The causal agent was originally identified in Brazil as Ceratocystis fimbriata, which is considered by some as a complex of many cryptic species, and four new species on mango trees were distinguished from C. fimbriata based on variation in internal transcribed spacer sequences. In the present study, phylogenetic analyses using DNA sequences of mating type genes, TEF-1α, and β-tubulin failed to identify lineages corresponding to the four new species names. Further, mating experiments found that the mango isolates representing the new species were interfertile with each other and a tester strain from sweet potato (Ipomoea batatas), on which the name C. fimbriata is based, and there was little morphological variation among the mango isolates. Microsatellite markers found substantial differentiation among mango isolates at the regional and population levels, but certain microsatellite genotypes were commonly found in multiple populations, suggesting that these genotypes had been disseminated in infected nursery stock. The most common microsatellite genotypes corresponded to the four recently named species (C. manginecans, C. acaciivora, C. mangicola, and C. mangivora), which are considered synonyms of C. fimbriata. This study points to the potential problems of naming new species based on introduced genotypes of a pathogen, the value of an understanding of natural variation within and among populations, and the importance of phenotype in delimiting species.

  11. Chytrid fungus acts as a generalist pathogen infecting species-rich amphibian families in Brazilian rainforests.

    PubMed

    Valencia-Aguilar, Anyelet; Ruano-Fajardo, Gustavo; Lambertini, Carolina; da Silva Leite, Domingos; Toledo, Luís Felipe; Mott, Tamí

    2015-05-11

    The fungus Batrachochytrium dendrobatidis (Bd) is among the main causes of declines in amphibian populations. This fungus is considered a generalist pathogen because it infects several species and spreads rapidly in the wild. To date, Bd has been detected in more than 100 anuran species in Brazil, mostly in the southern portion of the Atlantic forest. Here, we report survey data from some poorly explored regions; these data considerably extend current information on the distribution of Bd in the northern Atlantic forest region. In addition, we tested the hypothesis that Bd is a generalist pathogen in this biome. We also report the first positive record for Bd in an anuran caught in the wild in Amazonia. In total, we screened 90 individuals (from 27 species), of which 39 individuals (from 22 species) were Bd-positive. All samples collected in Bahia (2 individuals), Pernambuco (3 individuals), Pará (1 individual), and Minas Gerais (1 individual) showed positive results for Bd. We found a positive correlation between anuran richness per family and the number of infected species in the Atlantic forest, supporting previous observations that Bd lacks strong host specificity; of 38% of the anuran species in the Atlantic forest that were tested for Bd infection, 25% showed positive results. The results of our study exemplify the pandemic and widespread nature of Bd infection in amphibians. PMID:25958806

  12. Chytrid fungus acts as a generalist pathogen infecting species-rich amphibian families in Brazilian rainforests.

    PubMed

    Valencia-Aguilar, Anyelet; Ruano-Fajardo, Gustavo; Lambertini, Carolina; da Silva Leite, Domingos; Toledo, Luís Felipe; Mott, Tamí

    2015-05-11

    The fungus Batrachochytrium dendrobatidis (Bd) is among the main causes of declines in amphibian populations. This fungus is considered a generalist pathogen because it infects several species and spreads rapidly in the wild. To date, Bd has been detected in more than 100 anuran species in Brazil, mostly in the southern portion of the Atlantic forest. Here, we report survey data from some poorly explored regions; these data considerably extend current information on the distribution of Bd in the northern Atlantic forest region. In addition, we tested the hypothesis that Bd is a generalist pathogen in this biome. We also report the first positive record for Bd in an anuran caught in the wild in Amazonia. In total, we screened 90 individuals (from 27 species), of which 39 individuals (from 22 species) were Bd-positive. All samples collected in Bahia (2 individuals), Pernambuco (3 individuals), Pará (1 individual), and Minas Gerais (1 individual) showed positive results for Bd. We found a positive correlation between anuran richness per family and the number of infected species in the Atlantic forest, supporting previous observations that Bd lacks strong host specificity; of 38% of the anuran species in the Atlantic forest that were tested for Bd infection, 25% showed positive results. The results of our study exemplify the pandemic and widespread nature of Bd infection in amphibians.

  13. Cryptic species, native populations and biological invasions by a eucalypt forest pathogen.

    PubMed

    Pérez, Guillermo; Slippers, Bernard; Wingfield, Michael J; Wingfield, Brenda D; Carnegie, Angus J; Burgess, Treena I

    2012-09-01

    Human-associated introduction of pathogens and consequent invasions is very evident in areas where no related organisms existed before. In areas where related but distinct populations or closely related cryptic species already exist, the invasion process is much harder to unravel. In this study, the population structure of the Eucalyptus leaf pathogen Teratosphaeria nubilosa was studied within its native range in Australia, including both commercial plantations and native forests. A collection of 521 isolates from across its distribution was characterized using eight microsatellite loci, resulting in 112 multilocus haplotypes (MLHs). Multivariate and Bayesian analyses of the population conducted in structure revealed three genetically isolated groups (A, B and C), with no evidence for recombination or hybridization among groups, even when they co-occur in the same plantation. DNA sequence data of the ITS (n = 32), β-tubulin (n = 32) and 27 anonymous loci (n = 16) were consistent with microsatellite data in suggesting that T. nubilosa should be considered as a species complex. Patterns of genetic diversity provided evidence of biological invasions by the pathogen within Australia in the states of Western Australia and New South Wales and helped unravel the pattern of invasion beyond Australia into New Zealand, Brazil and Uruguay. No significant genetic differences in pathogen populations collected in native forests and commercial plantations were observed. This emphasizes the importance of sanitation in the acquisition of nursery stock for the establishment of commercial plantations.

  14. Generation of Reactive Oxygen Species via NOXa Is Important for Development and Pathogenicity of Mycosphaerella graminicola.

    PubMed

    Choi, Yoon-E; Lee, Changsu; Goodwin, Stephen B

    2016-03-01

    The ascomycete fungus Mycosphaerella graminicola (synonym Zymoseptoria tritici) is an important pathogen of wheat causing economically significant losses. The primary nutritional mode of this fungus is thought to be hemibiotrophic. This pathogenic lifestyle is associated with an early biotrophic stage of nutrient uptake followed by a necrotrophic stage aided possibly by production of a toxin or reactive oxygen species (ROS). In many other fungi, the genes CREA and AREA are important during the biotrophic stage of infection, while the NOXa gene product is important during necrotrophic growth. To test the hypothesis that these genes are important for pathogenicity of M. graminicola, we employed an over-expression strategy for the selected target genes CREA, AREA, and NOXa, which might function as regulators of nutrient acquisition or ROS generation. Increased expressions of CREA, AREA, and NOXa in M. graminicola were confirmed via quantitative real-time PCR and strains were subsequently assayed for pathogenicity. Among them, the NOXa over-expression strain, NO2, resulted in significantly increased virulence. Moreover, instead of the usual filamentous growth, we observed a predominance of yeast-like growth of NO2 which was correlated with ROS production. Our data indicate that ROS generation via NOXa is important to pathogenicity as well as development in M. graminicola. PMID:27103853

  15. Evaluation of two novel barcodes for species recognition of opportunistic pathogens in Fusarium.

    PubMed

    Al-Hatmi, Abdullah M S; Van Den Ende, A H G Gerrits; Stielow, J Benjamin; Van Diepeningen, Anne D; Seifert, Keith A; McCormick, Wayne; Assabgui, Rafik; Gräfenhan, Tom; De Hoog, G Sybren; Levesque, C André

    2016-02-01

    The genus Fusarium includes more than 200 species of which 73 have been isolated from human infections. Fusarium species are opportunistic human pathogens with variable aetiology. Species determination is best made with the combined phylogeny of protein-coding genes such as elongation factor (TEF1), RNA polymerase (RPB2) and the partial β-tubulin (BT2) gene. The internal transcribed spacers 1, 2 and 5.8S rRNA gene (ITS) have also been used, however, ITS cannot discriminate several closely related species and has nonorthologous copies in Fusarium. Currently, morphological approaches and tree-building methods are in use to define species and to discover hitherto undescribed species. Aftter a species is defined, DNA barcoding approaches can be used to identify species by the presence or absence of discrete nucleotide characters. We demonstrate the potential of two recently discovered DNA barcode loci, topoisomerase I (TOP1) and phosphoglycerate kinase (PGK), in combination with other routinely used markers such as TEF1, in an analysis of 144 Fusarium strains belonging to 52 species. Our barcoding study using TOP1 and PKG provided concordance of molecular data with TEF1. The currently accepted Fusarium species sampled were well supported in phylogenetic trees of both new markers.

  16. The plant pathogen Phytophthora andina emerged via hybridization of an unknown Phytophthora species and the Irish famine pathogen, P. infestans

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The global movement of plant pathogens threatens natural ecosystems, food security, and commercial interests. Introduction of a plant pathogen to new geographic regions has been the primary mechanism by which new pathogens have emerged. Another documented mechanism for the emergence of plant pathoge...

  17. Staphylococcal enterotoxin and its rapid identification in foods by enzyme-linked immunosorbent assay-based methodology.

    PubMed

    Bennett, Reginald W

    2005-06-01

    The problem of Staphylococcus aureus and other species as contaminants in the food supply remains significant on a global level. Time and temperature abuse of a food product contaminated with enterotoxigenic staphylococci can result in formation of enterotoxin, which can produce foodborne illness when the product is ingested. Between 100 and 200 ng of enterotoxin can cause symptoms consistent with staphylococcal intoxication. Although humans are the primary reservoirs of contamination, animals, air, dust, and food contact surfaces can serve as vehicles in the transfer of this pathogen to the food supply. Foods may become contaminated during production or processing and in homes or food establishments, where the organism can proliferate to high concentrations and subsequently produce enterotoxin. The staphylococcal enterotoxins are highly heat stable and can remain biologically active after exposure to retort temperatures. Prior to the development of serological methods for the identification of enterotoxin, monkeys (gastric intubation) and later kittens (intravenous injection) were used in assays for toxin detection. When enterotoxins were identified as mature proteins that were antigenic, serological assays were developed for use in the laboratory analysis of foods suspected of containing preformed enterotoxin. More recently developed methods are tracer-labeled immunoassays. Of these methods, the enzyme-linked immunosorbent assays are highly specific, highly sensitive, and rapid for the detection of enterotoxin in foods.

  18. Multiplex characterization of human pathogens including species and antibiotic-resistance gene identification.

    PubMed

    Barisˇ ić, Ivan; Petzka, Josefine; Schoenthaler, Silvia; Vierlinger, Klemens; Noehammer, Christa; Wiesinger-Mayr, Herbert

    2016-01-01

    The efficient medical treatment of infections requires detailed information about the pathogens involved and potential antibiotic-resistance mechanisms. The dramatically increasing incidence of multidrug-resistant bacteria especially highlights the importance of sophisticated diagnostic tests enabling a fast patient-customized therapy. However, the current molecular detection methods are limited to either the detection of species or only a few antibiotic-resistance genes.In this work, we present a human pathogen characterization assay using a rRNA gene microarray identifying 75 species comprising bacteria and fungi. A statistical classifier was developed to facilitate the automated species identification. Additionally, the clinically most important β-lactamases were identified simultaneously in a 100-plex reaction using padlock probes and the same microarray. The specificity and sensitivity of the combined assay was determined using clinical isolates. The detection limit was 10(5) c.f.u. ml(-1), recovering 89 % of the detectable β-lactamase-encoding genes specifically. The total assay time was less than 7 hand the modular character of the antibiotic-resistance detection allows the easy integration of further genetic targets. In summary, we present a fast, highly specific and sensitive multiplex pathogen characterization assay.

  19. Nitrogen Source-Dependent Capsule Induction in Human-Pathogenic Cryptococcus Species

    PubMed Central

    Frazzitta, Aubrey E.; Vora, Haily; Price, Michael S.; Tenor, Jennifer L.; Betancourt-Quiroz, Marisol; Toffaletti, Dena L.; Cheng, Nan

    2013-01-01

    Cryptococcus neoformans and C. gattii cause meningoencephalitis and are an increasing human health threat. These pathogenic Cryptococcus species are neurotropic and persist in the cerebrospinal fluid (CSF) of the mammalian host during infection. In order to survive in the host, pathogenic fungi must procure nutrients, such as carbon and nitrogen, from the CSF. To enhance our understanding of nutrient acquisition during central nervous system infection by Cryptococcus species, we examined the utilization of nitrogen sources available in CSF. We screened for the growth and capsule production of 817 global environmental and clinical isolates on various sources of nitrogen. Both environmental and clinical strains grew robustly on uric acid, Casamino Acids, creatinine, and asparagine as sole nitrogen sources. Urea induced the greatest magnitude of capsule induction. This induction was greater in Cryptococcus gattii than in C. neoformans. We confirmed the ability of nonpreferred nitrogen sources to increase capsule production in pathogenic species of Cryptococcus. Since urea is metabolized to ammonia and CO2 (a known signal for capsule induction), we examined urea metabolism mutants for their transcriptional response to urea regarding capsule production. The transcriptional profile of C. neoformans under urea-supplemented conditions revealed both similar and unique responses to other capsule-inducing conditions, including both intra- and extracellular urea utilization. As one of the most abundant nitrogen sources in the CSF, the ability of Cryptococcus to import urea and induce capsule production may substantially aid this yeast's survival and propagation in the host. PMID:23975889

  20. Metabolomics Analysis Reveals Specific Novel Tetrapeptide and Potential Anti-Inflammatory Metabolites in Pathogenic Aspergillus species.

    PubMed

    Lee, Kim-Chung; Tam, Emily W T; Lo, Ka-Ching; Tsang, Alan K L; Lau, Candy C Y; To, Kelvin K W; Chan, Jasper F W; Lam, Ching-Wan; Yuen, Kwok-Yung; Lau, Susanna K P; Woo, Patrick C Y

    2015-01-01

    Infections related to Aspergillus species have emerged to become an important focus in infectious diseases, as a result of the increasing use of immunosuppressive agents and high fatality associated with invasive aspergillosis. However, laboratory diagnosis of Aspergillus infections remains difficult. In this study, by comparing the metabolomic profiles of the culture supernatants of 30 strains of six pathogenic Aspergillus species (A. fumigatus, A. flavus, A. niger, A. terreus, A. nomius and A. tamarii) and 31 strains of 10 non-Aspergillus fungi, eight compounds present in all strains of the six Aspergillus species but not in any strain of the non-Aspergillus fungi were observed. One of the eight compounds, Leu-Glu-Leu-Glu, is a novel tetrapeptide and represents the first linear tetrapeptide observed in Aspergillus species, which we propose to be named aspergitide. Two other closely related Aspergillus-specific compounds, hydroxy-(sulfooxy)benzoic acid and (sulfooxy)benzoic acid, may possess anti-inflammatory properties, as 2-(sulfooxy)benzoic acid possesses a structure similar to those of aspirin [2-(acetoxy)benzoic acid] and salicylic acid (2-hydroxybenzoic acid). Further studies to examine the potentials of these Aspergillus-specific compounds for laboratory diagnosis of aspergillosis are warranted and further experiments will reveal whether Leu-Glu-Leu-Glu, hydroxy-(sulfooxy)benzoic acid and (sulfooxy)benzoic acid are virulent factors of the pathogenic Aspergillus species. PMID:26090713

  1. The Colletotrichum destructivum species complex – hemibiotrophic pathogens of forage and field crops

    PubMed Central

    Damm, U.; O'Connell, R.J.; Groenewald, J.Z.; Crous, P.W.

    2014-01-01

    Colletotrichum destructivum is an important plant pathogen, mainly of forage and grain legumes including clover, alfalfa, cowpea and lentil, but has also been reported as an anthracnose pathogen of many other plants worldwide. Several Colletotrichum isolates, previously reported as closely related to C. destructivum, are known to establish hemibiotrophic infections in different hosts. The inconsistent application of names to those isolates based on outdated species concepts has caused much taxonomic confusion, particularly in the plant pathology literature. A multilocus DNA sequence analysis (ITS, GAPDH, CHS-1, HIS3, ACT, TUB2) of 83 isolates of C. destructivum and related species revealed 16 clades that are recognised as separate species in the C. destructivum complex, which includes C. destructivum, C. fuscum, C. higginsianum, C. lini and C. tabacum. Each of these species is lecto-, epi- or neotypified in this study. Additionally, eight species, namely C. americae-borealis, C. antirrhinicola, C. bryoniicola, C. lentis, C. ocimi, C. pisicola, C. utrechtense and C. vignae are newly described. PMID:25492986

  2. Metabolomics Analysis Reveals Specific Novel Tetrapeptide and Potential Anti-Inflammatory Metabolites in Pathogenic Aspergillus species.

    PubMed

    Lee, Kim-Chung; Tam, Emily W T; Lo, Ka-Ching; Tsang, Alan K L; Lau, Candy C Y; To, Kelvin K W; Chan, Jasper F W; Lam, Ching-Wan; Yuen, Kwok-Yung; Lau, Susanna K P; Woo, Patrick C Y

    2015-06-17

    Infections related to Aspergillus species have emerged to become an important focus in infectious diseases, as a result of the increasing use of immunosuppressive agents and high fatality associated with invasive aspergillosis. However, laboratory diagnosis of Aspergillus infections remains difficult. In this study, by comparing the metabolomic profiles of the culture supernatants of 30 strains of six pathogenic Aspergillus species (A. fumigatus, A. flavus, A. niger, A. terreus, A. nomius and A. tamarii) and 31 strains of 10 non-Aspergillus fungi, eight compounds present in all strains of the six Aspergillus species but not in any strain of the non-Aspergillus fungi were observed. One of the eight compounds, Leu-Glu-Leu-Glu, is a novel tetrapeptide and represents the first linear tetrapeptide observed in Aspergillus species, which we propose to be named aspergitide. Two other closely related Aspergillus-specific compounds, hydroxy-(sulfooxy)benzoic acid and (sulfooxy)benzoic acid, may possess anti-inflammatory properties, as 2-(sulfooxy)benzoic acid possesses a structure similar to those of aspirin [2-(acetoxy)benzoic acid] and salicylic acid (2-hydroxybenzoic acid). Further studies to examine the potentials of these Aspergillus-specific compounds for laboratory diagnosis of aspergillosis are warranted and further experiments will reveal whether Leu-Glu-Leu-Glu, hydroxy-(sulfooxy)benzoic acid and (sulfooxy)benzoic acid are virulent factors of the pathogenic Aspergillus species.

  3. Staphylococcal response to oxidative stress

    PubMed Central

    Gaupp, Rosmarie; Ledala, Nagender; Somerville, Greg A.

    2012-01-01

    Staphylococci are a versatile genus of bacteria that are capable of causing acute and chronic infections in diverse host species. The success of staphylococci as pathogens is due in part to their ability to mitigate endogenous and exogenous oxidative and nitrosative stress. Endogenous oxidative stress is a consequence of life in an aerobic environment; whereas, exogenous oxidative and nitrosative stress are often due to the bacteria's interaction with host immune systems. To overcome the deleterious effects of oxidative and nitrosative stress, staphylococci have evolved protection, detoxification, and repair mechanisms that are controlled by a network of regulators. In this review, we summarize the cellular targets of oxidative stress, the mechanisms by which staphylococci sense oxidative stress and damage, oxidative stress protection and repair mechanisms, and regulation of the oxidative stress response. When possible, special attention is given to how the oxidative stress defense mechanisms help staphylococci control oxidative stress in the host. PMID:22919625

  4. Virulence of oomycete pathogens from Phragmites australis-invaded and noninvaded soils to seedlings of wetland plant species

    PubMed Central

    Crocker, Ellen V; Karp, Mary Ann; Nelson, Eric B

    2015-01-01

    Soil pathogens affect plant community structure and function through negative plant–soil feedbacks that may contribute to the invasiveness of non-native plant species. Our understanding of these pathogen-induced soil feedbacks has relied largely on observations of the collective impact of the soil biota on plant populations, with few observations of accompanying changes in populations of specific soil pathogens and their impacts on invasive and noninvasive species. As a result, the roles of specific soil pathogens in plant invasions remain unknown. In this study, we examine the diversity and virulence of soil oomycete pathogens in freshwater wetland soils invaded by non-native Phragmites australis (European common reed) to better understand the potential for soil pathogen communities to impact a range of native and non-native species and influence invasiveness. We isolated oomycetes from four sites over a 2-year period, collecting nearly 500 isolates belonging to 36 different species. These sites were dominated by species of Pythium, many of which decreased seedling survival of a range of native and invasive plants. Despite any clear host specialization, many of the Pythium species were differentially virulent to the native and non-native plant species tested. Isolates from invaded and noninvaded soils were equally virulent to given individual plant species, and no apparent differences in susceptibility were observed between the collective groups of native and non-native plant species. PMID:26078850

  5. Virulence of oomycete pathogens from Phragmites australis-invaded and noninvaded soils to seedlings of wetland plant species.

    PubMed

    Crocker, Ellen V; Karp, Mary Ann; Nelson, Eric B

    2015-06-01

    Soil pathogens affect plant community structure and function through negative plant-soil feedbacks that may contribute to the invasiveness of non-native plant species. Our understanding of these pathogen-induced soil feedbacks has relied largely on observations of the collective impact of the soil biota on plant populations, with few observations of accompanying changes in populations of specific soil pathogens and their impacts on invasive and noninvasive species. As a result, the roles of specific soil pathogens in plant invasions remain unknown. In this study, we examine the diversity and virulence of soil oomycete pathogens in freshwater wetland soils invaded by non-native Phragmites australis (European common reed) to better understand the potential for soil pathogen communities to impact a range of native and non-native species and influence invasiveness. We isolated oomycetes from four sites over a 2-year period, collecting nearly 500 isolates belonging to 36 different species. These sites were dominated by species of Pythium, many of which decreased seedling survival of a range of native and invasive plants. Despite any clear host specialization, many of the Pythium species were differentially virulent to the native and non-native plant species tested. Isolates from invaded and noninvaded soils were equally virulent to given individual plant species, and no apparent differences in susceptibility were observed between the collective groups of native and non-native plant species.

  6. Genomes of three tomato pathogens within the Ralstonia solanacearum species complex reveal significant evolutionary divergence

    PubMed Central

    2010-01-01

    Background The Ralstonia solanacearum species complex includes thousands of strains pathogenic to an unusually wide range of plant species. These globally dispersed and heterogeneous strains cause bacterial wilt diseases, which have major socio-economic impacts. Pathogenicity is an ancestral trait in R. solanacearum and strains with high genetic variation can be subdivided into four phylotypes, correlating to isolates from Asia (phylotype I), the Americas (phylotype IIA and IIB), Africa (phylotype III) and Indonesia (phylotype IV). Comparison of genome sequences strains representative of this phylogenetic diversity can help determine which traits allow this bacterium to be such a pathogen of so many different plant species and how the bacteria survive in many different habitats. Results The genomes of three tomato bacterial wilt pathogens, CFBP2957 (phy. IIA), CMR15 (phy. III) and PSI07 (phy. IV) were sequenced and manually annotated. These genomes were compared with those of three previously sequenced R. solanacearum strains: GMI1000 (tomato, phy. I), IPO1609 (potato, phy. IIB), and Molk2 (banana, phy. IIB). The major genomic features (size, G+C content, number of genes) were conserved across all of the six sequenced strains. Despite relatively high genetic distances (calculated from average nucleotide identity) and many genomic rearrangements, more than 60% of the genes of the megaplasmid and 70% of those on the chromosome are syntenic. The three new genomic sequences revealed the presence of several previously unknown traits, probably acquired by horizontal transfers, within the genomes of R. solanacearum, including a type IV secretion system, a rhi-type anti-mitotic toxin and two small plasmids. Genes involved in virulence appear to be evolving at a faster rate than the genome as a whole. Conclusions Comparative analysis of genome sequences and gene content confirmed the differentiation of R. solanacearum species complex strains into four phylotypes. Genetic

  7. Molecular characterization of pathogenic Fusarium species in cucurbit plants from Kermanshah province, Iran

    PubMed Central

    Chehri, K.; Salleh, B.; Yli-Mattila, T.; Reddy, K.R.N.; Abbasi, S.

    2011-01-01

    Fusarium is one of the important phytopathogenic genera of microfungi causing serious losses on cucurbit plants in Kermanshah province, the largest area of cucurbits plantation in Iran. Therefore, the objectives in this study were to isolate and identify disease-causing Fusarium spp. from infected cucurbit plants, to ascertain their pathogenicity, and to determine their phylogenetic relationships. A total of 100 Fusarium isolates were obtained from diseased cucurbit plants collected from fields in different geographic regions in Kermanshah province, Iran. According to morphological characters, all isolates were identified as Fusarium oxysporum, Fusarium proliferatum, Fusarium equiseti, Fusarium semitectum and Fusarium solani. All isolates of the five Fusarium spp. were evaluated for their pathogenicity on healthy cucumber (Cucumis sativus) and honeydew melon (Cucumis melo) seedlings in the glasshouse. F. oxysporum caused damping-off in 20–35 days on both cucurbit seedlings tested. Typical stem rot symptoms were observed within 15 days after inoculation with F. solani on both seedlings. Based on the internal transcribed spacer (ITS) regions of ribosomal DNA (rDNA) restriction fragment length polymorphism (RFLP) analysis, the five Fusarium species were divided into two major groups. In particular, isolates belonging to the F. solani species complex (FSSC) were separated into two RFLP types. Grouping among Fusarium strains derived from restriction analysis was in agreement with criteria used in morphological classification. Therefore, the PCR-ITS-RFLP method provides a simple and rapid procedure for the differentiation of Fusarium strains at species level. This is the first report on identification and pathogenicity of major plant pathogenic Fusarium spp. causing root and stem rot on cucurbits in Iran. PMID:23961146

  8. Chromosomal locus for staphylococcal enterotoxin B.

    PubMed Central

    Shafer, W M; Iandolo, J J

    1978-01-01

    The genetic locus of staphylococcal enterotoxin B (SEB) was investigated in the Staphylococcus aureus food-poisoning isolates, strains S6 and 277. Direct neutral sucrose gradient centrifugation analysis of sodium dodecyl sulfate-sodium chloride-mediated cleared lysates demonstrated that strain S6 contained a single 37S plasmid. Transductional analysis revealed that the 37S plasmid in S6 encoded for cadmium resistance (Cad) but not SEB. Additionally, elimination of cadmium resistance in S6 provided a plasmid-negative derivative that produced SEB at the same level as the parent. Examination of strain 277 showed two plasmids, a 37S species encoding for penicillin resistance (Penr) and a 21S species containing the gene(s) responsible for tetracycline resistance (Tetr). Elimination of the 37S, penr plasmid in 277 had no effect on SEB production, whereas introduction of the 21S tetr plasmid via transformation into strain 8325 (SEB--) did not confer enterotoxigenesis upon the transformants. The data obtained in this investigation suggest that the SEB gene(s) in these food-poisoning isolates of S. aureus is chromosomal. Images PMID:669796

  9. Intra- and inter-species interactions within biofilms of important foodborne bacterial pathogens

    PubMed Central

    Giaouris, Efstathios; Heir, Even; Desvaux, Mickaël; Hébraud, Michel; Møretrø, Trond; Langsrud, Solveig; Doulgeraki, Agapi; Nychas, George-John; Kačániová, Miroslava; Czaczyk, Katarzyna; Ölmez, Hülya; Simões, Manuel

    2015-01-01

    A community-based sessile life style is the normal mode of growth and survival for many bacterial species. Under such conditions, cell-to-cell interactions are inevitable and ultimately lead to the establishment of dense, complex and highly structured biofilm populations encapsulated in a self-produced extracellular matrix and capable of coordinated and collective behavior. Remarkably, in food processing environments, a variety of different bacteria may attach to surfaces, survive, grow, and form biofilms. Salmonella enterica, Listeria monocytogenes, Escherichia coli, and Staphylococcus aureus are important bacterial pathogens commonly implicated in outbreaks of foodborne diseases, while all are known to be able to create biofilms on both abiotic and biotic surfaces. Particularly challenging is the attempt to understand the complexity of inter-bacterial interactions that can be encountered in such unwanted consortia, such as competitive and cooperative ones, together with their impact on the final outcome of these communities (e.g., maturation, physiology, antimicrobial resistance, virulence, dispersal). In this review, up-to-date data on both the intra- and inter-species interactions encountered in biofilms of these pathogens are presented. A better understanding of these interactions, both at molecular and biophysical levels, could lead to novel intervention strategies for controlling pathogenic biofilm formation in food processing environments and thus improve food safety. PMID:26347727

  10. Species Tree Estimation for the Late Blight Pathogen, Phytophthora infestans, and Close Relatives

    PubMed Central

    Blair, Jaime E.; Coffey, Michael D.; Martin, Frank N.

    2012-01-01

    To better understand the evolutionary history of a group of organisms, an accurate estimate of the species phylogeny must be known. Traditionally, gene trees have served as a proxy for the species tree, although it was acknowledged early on that these trees represented different evolutionary processes. Discordances among gene trees and between the gene trees and the species tree are also expected in closely related species that have rapidly diverged, due to processes such as the incomplete sorting of ancestral polymorphisms. Recently, methods have been developed for the explicit estimation of species trees, using information from multilocus gene trees while accommodating heterogeneity among them. Here we have used three distinct approaches to estimate the species tree for five Phytophthora pathogens, including P. infestans, the causal agent of late blight disease in potato and tomato. Our concatenation-based “supergene” approach was unable to resolve relationships even with data from both the nuclear and mitochondrial genomes, and from multiple isolates per species. Our multispecies coalescent approach using both Bayesian and maximum likelihood methods was able to estimate a moderately supported species tree showing a close relationship among P. infestans, P. andina, and P. ipomoeae. The topology of the species tree was also identical to the dominant phylogenetic history estimated in our third approach, Bayesian concordance analysis. Our results support previous suggestions that P. andina is a hybrid species, with P. infestans representing one parental lineage. The other parental lineage is not known, but represents an independent evolutionary lineage more closely related to P. ipomoeae. While all five species likely originated in the New World, further study is needed to determine when and under what conditions this hybridization event may have occurred. PMID:22615869

  11. The Plant Pathogen Phytophthora andina Emerged via Hybridization of an Unknown Phytophthora Species and the Irish Potato Famine Pathogen, P. infestans

    PubMed Central

    Goss, Erica M.; Cardenas, Martha E.; Myers, Kevin; Forbes, Gregory A.; Fry, William E.; Restrepo, Silvia; Grünwald, Niklaus J.

    2011-01-01

    Emerging plant pathogens have largely been a consequence of the movement of pathogens to new geographic regions. Another documented mechanism for the emergence of plant pathogens is hybridization between individuals of different species or subspecies, which may allow rapid evolution and adaptation to new hosts or environments. Hybrid plant pathogens have traditionally been difficult to detect or confirm, but the increasing ease of cloning and sequencing PCR products now makes the identification of species that consistently have genes or alleles with phylogenetically divergent origins relatively straightforward. We investigated the genetic origin of Phytophthora andina, an increasingly common pathogen of Andean crops Solanum betaceum, S. muricatum, S. quitoense, and several wild Solanum spp. It has been hypothesized that P. andina is a hybrid between the potato late blight pathogen P. infestans and another Phytophthora species. We tested this hypothesis by cloning four nuclear loci to obtain haplotypes and using these loci to infer the phylogenetic relationships of P. andina to P. infestans and other related species. Sequencing of cloned PCR products in every case revealed two distinct haplotypes for each locus in P. andina, such that each isolate had one allele derived from a P. infestans parent and a second divergent allele derived from an unknown species that is closely related but distinct from P. infestans, P. mirabilis, and P. ipomoeae. To the best of our knowledge, the unknown parent has not yet been collected. We also observed sequence polymorphism among P. andina isolates at three of the four loci, many of which segregate between previously described P. andina clonal lineages. These results provide strong support that P. andina emerged via hybridization between P. infestans and another unknown Phytophthora species also belonging to Phytophthora clade 1c. PMID:21949727

  12. The staphylococcal enterotoxin (SE) family

    PubMed Central

    Krakauer, Teresa; Stiles, Bradley G

    2013-01-01

    Staphylococcus aureus plays an important role in numerous human cases of food poisoning, soft tissue, and bone infections, as well as potentially lethal toxic shock. This common bacterium synthesizes various virulence factors that include staphylococcal enterotoxins (SEs). These protein toxins bind directly to major histocompatibility complex class II on antigen-presenting cells and specific Vβ regions of T-cell receptors, resulting in potentially life-threatening stimulation of the immune system. Picomolar concentrations of SEs ultimately elicit proinflammatory cytokines that can induce fever, hypotension, multi-organ failure, and lethal shock. Various in vitro and in vivo models have provided important tools for studying the biological effects of, as well as potential vaccines/therapeutics against, the SEs. This review succinctly presents known physical and biological properties of the SEs, including various intervention strategies. In particular, SEB will often be portrayed as per biodefense concerns dating back to the 1960s. PMID:23959032

  13. Tree diversity and the role of non-host neighbour tree species in reducing fungal pathogen infestation

    PubMed Central

    Hantsch, Lydia; Bien, Steffen; Radatz, Stine; Braun, Uwe; Auge, Harald; Bruelheide, Helge

    2014-01-01

    The degree to which plant pathogen infestation occurs in a host plant is expected to be strongly influenced by the level of species diversity among neighbouring host and non-host plant species. Since pathogen infestation can negatively affect host plant performance, it can mediate the effects of local biodiversity on ecosystem functioning. We tested the effects of tree diversity and the proportion of neighbouring host and non-host species with respect to the foliar fungal pathogens of Tilia cordata and Quercus petraea in the Kreinitz tree diversity experiment in Germany. We hypothesized that fungal pathogen richness increases while infestation decreases with increasing local tree diversity. In addition, we tested whether fungal pathogen richness and infestation are dependent on the proportion of host plant species present or on the proportion of particular non-host neighbouring tree species. Leaves of the two target species were sampled across three consecutive years with visible foliar fungal pathogens on the leaf surface being identified macro- and microscopically. Effects of diversity among neighbouring trees were analysed: (i) for total fungal species richness and fungal infestation on host trees and (ii) for infestation by individual fungal species. We detected four and five fungal species on T. cordata and Q. petraea, respectively. High local tree diversity reduced (i) total fungal species richness and infestation of T. cordata and fungal infestation of Q. petraea and (ii) infestation by three host-specialized fungal pathogen species. These effects were brought about by local tree diversity and were independent of host species proportion. In general, host species proportion had almost no effect on fungal species richness and infestation. Strong effects associated with the proportion of particular non-host neighbouring tree species on fungal species richness and infestation were, however, recorded. Synthesis. For the first time, we experimentally

  14. Reactive oxygen species involved in regulating fruit senescence and fungal pathogenicity.

    PubMed

    Tian, Shiping; Qin, Guozheng; Li, Boqiang

    2013-08-01

    Senescence is a vital aspect of fruit life cycles, and directly affects fruit quality and resistance to pathogens. Reactive oxygen species (ROS), as the primary mediators of oxidative damage in plants, are involved in senescence. Mitochondria are the main ROS and free radical source. Oxidative damage to mitochondrial proteins caused by ROS is implicated in the process of senescence, and a number of senescence-related disorders in a variety of organisms. However, the specific sites of ROS generation in mitochondria remain largely unknown. Recent discoveries have ascertained that fruit senescence is greatly related to ROS and incidental oxidative damage of mitochondrial protein. Special mitochondrial proteins involved in fruit senescence have been identified as the targets of ROS. We focus in discussion on our recent advances in exploring the mechanisms of how ROS regulate fruit senescence and fungal pathogenicity.

  15. Pathogenicity of some Fusarium species associated with superficial blemishes of potato tubers.

    PubMed

    Gashgari, Rukaia M; Gherbawy, Youssuf A

    2013-01-01

    As an organ for reserve and propagation, the tuber grows underground and is in contact with soil-borne microorganisms, making it potentially exposed to blemishes. Therefore, the objective of this study was the possibility of using some modern methods of molecular diagnostics and detection of the presence of fungal contaminants in potato blemishes in Al-Qasim (Saudi Arabia). Polygonal lesions were the most observed blemish type in the collected samples. One hundred and sixty isolates were recovered from different types of blemishes obtained in this study. Fusarium, Penicillium, Ilyonectria, Alternaria and Rhizoctonia were the most common genera collected from different blemish types. Using ITS region sequencing, all collected fungi were identified at the species level. All Fusarium strains collected during this study were used to detect their pathogenicity against potato tubers. This is the first comprehensive report on the identification of major pathogenic fungi isolated from potato tuber blemishes in Saudi Arabia.

  16. Multiple Pathogens Including Potential New Species in Tick Vectors in Côte d’Ivoire

    PubMed Central

    Ehounoud, Cyrille Bilé; Yao, Kouassi Patrick; Dahmani, Mustapha; Achi, Yaba Louise; Amanzougaghene, Nadia; Kacou N’Douba, Adèle; N’Guessan, Jean David; Raoult, Didier; Fenollar, Florence; Mediannikov, Oleg

    2016-01-01

    Background Our study aimed to assess the presence of different pathogens in ticks collected in two regions in Côte d’Ivoire. Methodology/Principal Findings Real-time PCR and standard PCR assays coupled to sequencing were used. Three hundred and seventy eight (378) ticks (170 Amblyomma variegatum, 161 Rhipicepalus microplus, 3 Rhipicephalus senegalensis, 27 Hyalomma truncatum, 16 Hyalomma marginatum rufipes, and 1 Hyalomma impressum) were identified and analyzed. We identified as pathogenic bacteria, Rickettsia africae in Am. variegatum (90%), Rh. microplus (10%) and Hyalomma spp. (9%), Rickettsia aeschlimannii in Hyalomma spp. (23%), Rickettsia massiliae in Rh. senegalensis (33%) as well as Coxiella burnetii in 0.2%, Borrelia sp. in 0.2%, Anaplasma centrale in 0.2%, Anaplasma marginale in 0.5%, and Ehrlichia ruminantium in 0.5% of all ticks. Potential new species of Borrelia, Anaplasma, and Wolbachia were detected. Candidatus Borrelia africana and Candidatus Borrelia ivorensis (detected in three ticks) are phylogenetically distant from both the relapsing fever group and Lyme disease group borreliae; both were detected in Am. variegatum. Four new genotypes of bacteria from the Anaplasmataceae family were identified, namely Candidatus Anaplasma ivorensis (detected in three ticks), Candidatus Ehrlichia urmitei (in nine ticks), Candidatus Ehrlichia rustica (in four ticks), and Candidatus Wolbachia ivorensis (in one tick). Conclusions/Significance For the first time, we demonstrate the presence of different pathogens such as R. aeschlimannii, C. burnetii, Borrelia sp., A. centrale, A. marginale, and E. ruminantium in ticks in Côte d’Ivoire as well as potential new species of unknown pathogenicity. PMID:26771308

  17. Hybridization of powdery mildew strains gives rise to pathogens on novel agricultural crop species.

    PubMed

    Menardo, Fabrizio; Praz, Coraline R; Wyder, Stefan; Ben-David, Roi; Bourras, Salim; Matsumae, Hiromi; McNally, Kaitlin E; Parlange, Francis; Riba, Andrea; Roffler, Stefan; Schaefer, Luisa K; Shimizu, Kentaro K; Valenti, Luca; Zbinden, Helen; Wicker, Thomas; Keller, Beat

    2016-02-01

    Throughout the history of agriculture, many new crop species (polyploids or artificial hybrids) have been introduced to diversify products or to increase yield. However, little is known about how these new crops influence the evolution of new pathogens and diseases. Triticale is an artificial hybrid of wheat and rye, and it was resistant to the fungal pathogen powdery mildew (Blumeria graminis) until 2001 (refs. 1,2,3). We sequenced and compared the genomes of 46 powdery mildew isolates covering several formae speciales. We found that B. graminis f. sp. triticale, which grows on triticale and wheat, is a hybrid between wheat powdery mildew (B. graminis f. sp. tritici) and mildew specialized on rye (B. graminis f. sp. secalis). Our data show that the hybrid of the two mildews specialized on two different hosts can infect the hybrid plant species originating from those two hosts. We conclude that hybridization between mildews specialized on different species is a mechanism of adaptation to new crops introduced by agriculture. PMID:26752267

  18. Proteomic analysis of cell wall in four pathogenic species of Candida exposed to oxidative stress.

    PubMed

    Ramírez-Quijas, Mayra Denisse; López-Romero, Everardo; Cuéllar-Cruz, Mayra

    2015-10-01

    In order for Candida species to adhere and colonize human host cells they must express cell wall proteins (CWP) and adapt to reactive oxygen species (ROS) generated by phagocytic cells of the human host during the respiratory burst. However, how these pathogens change the expression of CWP in response to oxidative stress (OSR) is not known. Here, fifteen moonlight-like CWP were identified that expressed differentially in four species of Candida after they were exposed to H2O2 or menadione (O2(-)). These proteins included: (i) glycolytic enzymes, such as glyceraldehyde-3-phosphate dehydrogenase (Gapdh), fructose-bisphosphate aldolase (Fba1), phosphoglycerate mutase (Gpm1), phosphoglycerate kinase (Pgk), pyruvate kinase (Pk) and enolase (Eno1); (ii) the heat shock proteins Ssb1 and Ssa2; (iii) OSR proteins such as peroxyredoxin (Tsa1), the stress protein Ddr48 (Ddr48) and glutathione reductase (Glr1); (iv) other metabolic enzymes such as ketol-acid reductoisomerase (Ilv5) and pyruvate decarboxylase (Pdc1); and (v) other proteins such as elongation factor 1-beta (Efb1) and the 14-3-3 protein homolog. RT-PCR revealed that transcription of the genes coding for some of the identified CWP are differentially regulated. To our knowledge this is the first report showing that moonlight-like CWP are the first line of defense of Candida against ROS, and that they are differentially regulated in each of these pathogens.

  19. Synergistic fungicidal activity of the lipopeptide bacillomycin D with amphotericin B against pathogenic Candida species.

    PubMed

    Tabbene, Olfa; Di Grazia, Antonio; Azaiez, Sana; Ben Slimene, Imen; Elkahoui, Salem; Alfeddy, Mohamed Najib; Casciaro, Bruno; Luca, Vincenzo; Limam, Ferid; Mangoni, Maria Luisa

    2015-06-01

    In the present study, the synergism of the lipopeptide bacillomycin D in combination with the polyene amphotericin B against pathogenic Candida species is described along with their potential cytotoxicity against mammalian cells. Bacillomycin D inhibited the growth of various Candida species at minimal concentrations from 12.5 to 25 μg ml(-1). Furthermore, it showed a synergistic effect with the antifungal drug amphotericin B in inhibiting the growth of Candida strains, with fractional inhibitory concentration indices ranging from 0.28 to 0.5. Time killing studies revealed a >2-log reduction in the viability of Candida albicans ATCC 10231 cells after 3 h incubation with the combination amphotericin B plus bacillomycin D, at their subinhibitory concentration. Interestingly, when the two drugs were used together at those dosages displaying a synergism in the anti-Candida activity, no cytotoxic effect was observed against mammalian cells. Therefore, the combination bacillomycin D/amphotericin B may represent a valid alternative to conventional antifungals for topical treatment of C. albicans infections. To the best of our knowledge, this is the first report describing the in vitro interaction between the antifungal drug amphotericin B and bacillomycin D against pathogenic Candida species.

  20. Phylogenetic, Morphological, and Pathogenic Characterization of Alternaria Species Associated with Fruit Rot of Blueberry in California.

    PubMed

    Zhu, X Q; Xiao, C L

    2015-12-01

    Fruit rot caused by Alternaria spp. is one of the most important factors affecting the postharvest quality and shelf life of blueberry fruit. The aims of this study were to characterize Alternaria isolates using morphological and molecular approaches and test their pathogenicity to blueberry fruit. Alternaria spp. isolates were collected from decayed blueberry fruit in the Central Valley of California during 2012 and 2013. In total, 283 isolates were obtained and five species of Alternaria, including Alternaria alternata, A. tenuissima, A. arborescens, A. infectoria, and A. rosae, were identified based on DNA sequences of the plasma membrane ATPase, Alt a1 and Calmodulin gene regions in combination with morphological characters of the culture and sporulation. Of the 283 isolates, 61.5% were identified as A. alternata, 32.9% were A. arborescens, 5.0% were A. tenuissima, and only one isolate of A. infectoria and one isolate of A. rosae were found. These fungi were able to grow at temperatures from 0 to 35°C, and mycelial growth was arrested at 40°C. Optimal radial growth occurred between 20 to 30°C. Pathogenicity tests showed that all five Alternaria spp. were pathogenic on blueberry fruit at 0, 4, and 20°C, with A. alternata, A. arborescens, and A. tenuissima being the most virulent species, followed by A. infectoria and A. rosae. Previously A. tenuissima has been reported to be the primary cause of Alternaria fruit rot of blueberry worldwide. Our results indicated that the species composition of Alternaria responsible for Alternaria fruit rot in blueberry can be dependent on geographical region. A. alternata, A. arborescens, A. infectoria, and A. rosae are reported for the first time on blueberry in California. This is also the first report of A. infectoria and A. rosae infecting blueberry fruit.

  1. Phylogenetic, Morphological, and Pathogenic Characterization of Alternaria Species Associated with Fruit Rot of Blueberry in California.

    PubMed

    Zhu, X Q; Xiao, C L

    2015-12-01

    Fruit rot caused by Alternaria spp. is one of the most important factors affecting the postharvest quality and shelf life of blueberry fruit. The aims of this study were to characterize Alternaria isolates using morphological and molecular approaches and test their pathogenicity to blueberry fruit. Alternaria spp. isolates were collected from decayed blueberry fruit in the Central Valley of California during 2012 and 2013. In total, 283 isolates were obtained and five species of Alternaria, including Alternaria alternata, A. tenuissima, A. arborescens, A. infectoria, and A. rosae, were identified based on DNA sequences of the plasma membrane ATPase, Alt a1 and Calmodulin gene regions in combination with morphological characters of the culture and sporulation. Of the 283 isolates, 61.5% were identified as A. alternata, 32.9% were A. arborescens, 5.0% were A. tenuissima, and only one isolate of A. infectoria and one isolate of A. rosae were found. These fungi were able to grow at temperatures from 0 to 35°C, and mycelial growth was arrested at 40°C. Optimal radial growth occurred between 20 to 30°C. Pathogenicity tests showed that all five Alternaria spp. were pathogenic on blueberry fruit at 0, 4, and 20°C, with A. alternata, A. arborescens, and A. tenuissima being the most virulent species, followed by A. infectoria and A. rosae. Previously A. tenuissima has been reported to be the primary cause of Alternaria fruit rot of blueberry worldwide. Our results indicated that the species composition of Alternaria responsible for Alternaria fruit rot in blueberry can be dependent on geographical region. A. alternata, A. arborescens, A. infectoria, and A. rosae are reported for the first time on blueberry in California. This is also the first report of A. infectoria and A. rosae infecting blueberry fruit. PMID:26267542

  2. The Janus face of reactive oxygen species in resistance and susceptibility of plants to necrotrophic and biotrophic pathogens.

    PubMed

    Barna, B; Fodor, J; Harrach, B D; Pogány, M; Király, Z

    2012-10-01

    Plant pathogens can be divided into biotrophs and necrotrophs according to their different life styles; biotrophs prefer living, while necrotrophs prefer dead cells for nutritional purposes. Therefore tissue necrosis caused by reactive oxygen species (ROS) during pathogen infection increases host susceptibility to necrotrophic, but resistance to biotrophic pathogen. Consequently, elevation of antioxidant capacity of plants enhances their tolerance to development of necroses caused by necrotrophic pathogens. Plant hormones can strongly influence induction of ROS and antioxidants, thereby influencing susceptibility or resistance of plants to pathogens. Pathogen-induced ROS themselves are considered as signaling molecules. Generally, salicylic acid (SA) signaling induces defense against biotrophic pathogens, whereas jasmonic acid (JA) against necrotrophic pathogens. Furthermore pathogens can modify plant's defense signaling network for their own benefit by changing phytohormone homeostasis. On the other hand, ROS are harmful also to the pathogens, consequently they try to defend themselves by elevating antioxidant activity and secreting ROS scavengers in the infected tissue. The Janus face nature of ROS and plant cell death on biotrophic and on necrotrophic pathogens is also supported by the experiments with BAX inhibitor-1 and the mlo mutation of Mlo gene in barley. It was found that ROS and elevated plant antioxidant activity play an important role in systemic acquired resistance (SAR) and induced systemic resistance (ISR), as well as in mycorrhiza induced abiotic and biotic stress tolerance of plants.

  3. Thermal Augmentation of Vancomycin Against Staphylococcal Biofilms.

    PubMed

    Sturtevant, Rachael A; Sharma, Prannda; Pavlovsky, Leonid; Stewart, Elizabeth J; Solomon, Michael J; Younger, John G

    2015-08-01

    Given the increasing evidence of safe application of elevated temperature in other clinical contexts, we consider the potential for supplemental hyperthermia to augment the effects of vancomycin against staphylococci, a major source of postoperative and posttraumatic sepsis. Laboratory reference strains and libraries of clinical blood isolates of Staphylococcus epidermidis and methicillin-resistant Staphylococcus aureus, both as planktonic cells and as established biofilms, were assessed for thermosensitivity and increased susceptibility to vancomycin in the setting of thermal treatment. In addition to viability measures, patterns of stress gene expression were assessed with quantitative polymerase chain reaction, and structural changes were measured using quantitative transmission electron microscopy. Laboratory strains of both species had reduced growth and biofilm viability at 45°C, a temperature commonly used in other domains such as adjuvant treatments of malignancy. Blood isolates of S. epidermidis were consistent in this regard as well, but significant between-isolate variability in thermosensitivity was seen in blood isolates of S. aureus. Expression profiling and ultrastructural measurements confirmed that elevated temperature was a substantial stressor with or without vancomycin treatment. Our findings suggest that temperature elevations shown to be tolerated in humans in other settings hold the potential to be used as an adjuvant to antibiotic therapy against staphylococcal biofilms. PMID:25784524

  4. Hedgehogs and Mustelid Species: Major Carriers of Pathogenic Leptospira, a Survey in 28 Animal Species in France (20122015)

    PubMed Central

    Raton, Vincent; Zilber, Anne-Laure; Gasqui, Patrick; Faure, Eva; Baurier, Florence; Vourc’h, Gwenaël; Kodjo, Angeli; Combes, Benoît

    2016-01-01

    Human leptospirosis is a zoonotic and potentially fatal disease that has increasingly been reported in both developing and developed countries, including France. However, our understanding of the basic aspects of the epidemiology of this disease, including the source of Leptospira serogroup Australis infections in humans and domestic animals, remains incomplete. We investigated the genetic diversity of Leptospira in 28 species of wildlife other than rats using variable number tandem repeat (VNTR) and multispacer sequence typing (MST). The DNA of pathogenic Leptospira was detected in the kidney tissues of 201 individuals out of 3,738 tested individuals. A wide diversity, including 50 VNTR profiles and 8 MST profiles, was observed. Hedgehogs and mustelid species had the highest risk of being infected (logistic regression, OR = 66.8, CI95% = 30.9–144 and OR = 16.7, CI95% = 8.7–31.8, respectively). Almost all genetic profiles obtained from the hedgehogs were related to Leptospira interrogans Australis, suggesting the latter as a host-adapted bacterium, whereas mustelid species were infected by various genotypes, suggesting their interaction with Leptospira was different. By providing an inventory of the circulating strains of Leptospira and by pointing to hedgehogs as a potential reservoir of L. interrogans Australis, our study advances current knowledge on Leptospira animal carriers, and this information could serve to enhance epidemiological investigations in the future. PMID:27680672

  5. Brevibacillus laterosporus, a Pathogen of Invertebrates and a Broad-Spectrum Antimicrobial Species

    PubMed Central

    Ruiu, Luca

    2013-01-01

    Brevibacillus laterosporus, a bacterium characterized by the production of a unique canoe-shaped lamellar body attached to one side of the spore, is a natural inhabitant of water, soil and insects. Its biopesticidal potential has been reported against insects in different orders including Coleoptera, Lepidoptera, Diptera and against nematodes and mollusks. In addition to its pathogenicity against invertebrates, different B. laterosporus strains show a broad-spectrum antimicrobial activity including activity against phytopathogenic bacteria and fungi. A wide variety of molecules, including proteins and antibiotics, have been associated with the observed pathogenicity and mode of action. Before being considered as a biological control agent against plant pathogens, the antifungal and antibacterial properties of certain B. laterosporus strains have found medical interest, associated with the production of antibiotics with therapeutic effects. The recent whole genome sequencing of this species revealed its potential to produce polyketides, nonribosomal peptides, and toxins. Another field of growing interest is the use of this bacterium for bioremediation of contaminated sites by exploiting its biodegradation properties. The aim of the present review is to gather and discuss all recent findings on this emerging entomopathogen, giving a wider picture of its complex and broad-spectrum biocontrol activity. PMID:26462431

  6. Survival of pathogenic and lactobacilli species of fermented olives during simulated human digestion

    PubMed Central

    Arroyo-López, Francisco N.; Blanquet-Diot, Stéphanie; Denis, Sylvain; Thévenot, Jonathan; Chalancon, Sandrine; Alric, Monique; Rodríguez-Gómez, Francisco; Romero-Gil, Verónica; Jiménez-Díaz, Rufino; Garrido-Fernández, Antonio

    2014-01-01

    The present survey uses a dynamic gastric and small intestinal model to assess the survival of one pathogenic (Escherichia coli O157:H7 EDL 933) and three lactobacilli bacteria with probiotic potential (Lactobacillus rhamnosus GG, L. pentosus TOMC-LAB2, and L. pentosus TOMC-LAB4) during their passage through the human gastrointestinal tract using fermented olives as the food matrix. The data showed that the survival of the E. coli strain in the stomach and duodenum was very low, while its transit through the distal parts (jejunum and ileum) resulted in an increase in the pathogen population. The production of Shiga toxins by this enterohemorrhagic microorganism in the ileal effluents of the in vitro system was too low to be detected by ELISA assays. On the contrary, the three lactobacilli species assayed showed a considerable resistance to the gastric digestion, but not to the intestinal one, which affected their survival, and was especially evident in the case of both L. pentosus strains. In spite of this, high population levels for all assayed microorganisms were recovered at the end of the gastrointestinal passage. The results obtained in the present study show the potential use of table olives as a vehicle of beneficial microorganisms to the human body, as well as the need for good hygienic practices on the part of olive manufacturers in order to avoid the possibility of contamination by food-borne pathogens. PMID:25352842

  7. Gene genealogies reveal cryptic species and host preferences for the pine fungal pathogen Grosmannia clavigera.

    PubMed

    Alamouti, Sepideh M; Wang, Vincent; Diguistini, Scott; Six, Diana L; Bohlmann, Jörg; Hamelin, Richard C; Feau, Nicolas; Breuil, Colette

    2011-06-01

    Grosmannia clavigera is a fungal pathogen of pine forests in western North America and a symbiotic associate of two sister bark beetles: Dendroctonus ponderosae and D. jeffreyi. This fungus and its beetle associate D. ponderosae are expanding in large epidemics in western North America. Using the fungal genome sequence and gene annotations, we assessed whether fungal isolates from the two beetles inhabiting different species of pine in epidemic regions of western Canada and the USA, as well as in localized populations outside of the current epidemic, represent different genetic lineages. We characterized nucleotide variations in 67 genomic regions and selected 15 for the phylogenetic analysis. Using concordance of gene genealogies and distinct ecological characteristics, we identified two sibling phylogenetic species: Gc and Gs. Where the closely related Pinus ponderosa and P. jeffreyi are infested by localized populations of their respective beetles, Gc is present. In contrast, Gs is an exclusive associate of D. ponderosae mainly present on its primary host-tree P. contorta; however, in the current epidemic areas, it is also found in other pine species. These results suggest that the host-tree species and the beetle population dynamics may be important factors associated with the genetic divergence and diversity of fungal partners in the beetle-tree ecosystems. Gc represents the original G. clavigera holotype, and Gs should be described as a new species. PMID:21557782

  8. Deep-sea hydrothermal vent bacteria related to human pathogenic Vibrio species.

    PubMed

    Hasan, Nur A; Grim, Christopher J; Lipp, Erin K; Rivera, Irma N G; Chun, Jongsik; Haley, Bradd J; Taviani, Elisa; Choi, Seon Young; Hoq, Mozammel; Munk, A Christine; Brettin, Thomas S; Bruce, David; Challacombe, Jean F; Detter, J Chris; Han, Cliff S; Eisen, Jonathan A; Huq, Anwar; Colwell, Rita R

    2015-05-26

    Vibrio species are both ubiquitous and abundant in marine coastal waters, estuaries, ocean sediment, and aquaculture settings worldwide. We report here the isolation, characterization, and genome sequence of a novel Vibrio species, Vibrio antiquarius, isolated from a mesophilic bacterial community associated with hydrothermal vents located along the East Pacific Rise, near the southwest coast of Mexico. Genomic and phenotypic analysis revealed V. antiquarius is closely related to pathogenic Vibrio species, namely Vibrio alginolyticus, Vibrio parahaemolyticus, Vibrio harveyi, and Vibrio vulnificus, but sufficiently divergent to warrant a separate species status. The V. antiquarius genome encodes genes and operons with ecological functions relevant to the environment conditions of the deep sea and also harbors factors known to be involved in human disease caused by freshwater, coastal, and brackish water vibrios. The presence of virulence factors in this deep-sea Vibrio species suggests a far more fundamental role of these factors for their bacterial host. Comparative genomics revealed a variety of genomic events that may have provided an important driving force in V. antiquarius evolution, facilitating response to environmental conditions of the deep sea. PMID:25964331

  9. Deep-sea hydrothermal vent bacteria related to human pathogenic Vibrio species

    PubMed Central

    Hasan, Nur A.; Grim, Christopher J.; Lipp, Erin K.; Rivera, Irma N. G.; Chun, Jongsik; Haley, Bradd J.; Taviani, Elisa; Choi, Seon Young; Hoq, Mozammel; Munk, A. Christine; Brettin, Thomas S.; Bruce, David; Challacombe, Jean F.; Detter, J. Chris; Han, Cliff S.; Eisen, Jonathan A.; Huq, Anwar; Colwell, Rita R.

    2015-01-01

    Vibrio species are both ubiquitous and abundant in marine coastal waters, estuaries, ocean sediment, and aquaculture settings worldwide. We report here the isolation, characterization, and genome sequence of a novel Vibrio species, Vibrio antiquarius, isolated from a mesophilic bacterial community associated with hydrothermal vents located along the East Pacific Rise, near the southwest coast of Mexico. Genomic and phenotypic analysis revealed V. antiquarius is closely related to pathogenic Vibrio species, namely Vibrio alginolyticus, Vibrio parahaemolyticus, Vibrio harveyi, and Vibrio vulnificus, but sufficiently divergent to warrant a separate species status. The V. antiquarius genome encodes genes and operons with ecological functions relevant to the environment conditions of the deep sea and also harbors factors known to be involved in human disease caused by freshwater, coastal, and brackish water vibrios. The presence of virulence factors in this deep-sea Vibrio species suggests a far more fundamental role of these factors for their bacterial host. Comparative genomics revealed a variety of genomic events that may have provided an important driving force in V. antiquarius evolution, facilitating response to environmental conditions of the deep sea. PMID:25964331

  10. Gene genealogies reveal cryptic species and host preferences for the pine fungal pathogen Grosmannia clavigera.

    PubMed

    Alamouti, Sepideh M; Wang, Vincent; Diguistini, Scott; Six, Diana L; Bohlmann, Jörg; Hamelin, Richard C; Feau, Nicolas; Breuil, Colette

    2011-06-01

    Grosmannia clavigera is a fungal pathogen of pine forests in western North America and a symbiotic associate of two sister bark beetles: Dendroctonus ponderosae and D. jeffreyi. This fungus and its beetle associate D. ponderosae are expanding in large epidemics in western North America. Using the fungal genome sequence and gene annotations, we assessed whether fungal isolates from the two beetles inhabiting different species of pine in epidemic regions of western Canada and the USA, as well as in localized populations outside of the current epidemic, represent different genetic lineages. We characterized nucleotide variations in 67 genomic regions and selected 15 for the phylogenetic analysis. Using concordance of gene genealogies and distinct ecological characteristics, we identified two sibling phylogenetic species: Gc and Gs. Where the closely related Pinus ponderosa and P. jeffreyi are infested by localized populations of their respective beetles, Gc is present. In contrast, Gs is an exclusive associate of D. ponderosae mainly present on its primary host-tree P. contorta; however, in the current epidemic areas, it is also found in other pine species. These results suggest that the host-tree species and the beetle population dynamics may be important factors associated with the genetic divergence and diversity of fungal partners in the beetle-tree ecosystems. Gc represents the original G. clavigera holotype, and Gs should be described as a new species.

  11. Pathogenic Leptospira species express surface-exposed proteins belonging to the bacterial immunoglobulin superfamily.

    PubMed

    Matsunaga, James; Barocchi, Michele A; Croda, Julio; Young, Tracy A; Sanchez, Yolanda; Siqueira, Isadora; Bolin, Carole A; Reis, Mitermayer G; Riley, Lee W; Haake, David A; Ko, Albert I

    2003-08-01

    Proteins with bacterial immunoglobulin-like (Big) domains, such as the Yersinia pseudotuberculosis invasin and Escherichia coli intimin, are surface-expressed proteins that mediate host mammalian cell invasion or attachment. Here, we report the identification and characterization of a new family of Big domain proteins, referred to as Lig (leptospiral Ig-like) proteins, in pathogenic Leptospira. Screening of L. interrogans and L. kirschneri expression libraries with sera from leptospirosis patients identified 13 lambda phage clones that encode tandem repeats of the 90 amino acid Big domain. Two lig genes, designated ligA and ligB, and one pseudogene, ligC, were identified. The ligA and ligB genes encode amino-terminal lipoprotein signal peptides followed by 10 or 11 Big domain repeats and, in the case of ligB, a unique carboxy-terminal non-repeat domain. The organization of ligC is similar to that of ligB but contains mutations that disrupt the reading frame. The lig sequences are present in pathogenic but not saprophytic Leptospira species. LigA and LigB are expressed by a variety of virulent leptospiral strains. Loss of Lig protein and RNA transcript expression is correlated with the observed loss of virulence during culture attenuation of pathogenic strains. High-pressure freeze substitution followed by immunocytochemical electron microscopy confirmed that the Lig proteins were localized to the bacterial surface. Immunoblot studies with patient sera found that the Lig proteins are a major antigen recognized during the acute host infection. These observations demonstrate that the Lig proteins are a newly identified surface protein of pathogenic Leptospira, which by analogy to other bacterial immunoglobulin superfamily virulence factors, may play a role in host cell attachment and invasion during leptospiral pathogenesis. PMID:12890019

  12. Role of the Pre-neck Appendage Protein (Dpo7) from Phage vB_SepiS-phiIPLA7 as an Anti-biofilm Agent in Staphylococcal Species

    PubMed Central

    Gutiérrez, Diana; Briers, Yves; Rodríguez-Rubio, Lorena; Martínez, Beatriz; Rodríguez, Ana; Lavigne, Rob; García, Pilar

    2015-01-01

    Staphylococcus epidermidis and Staphylococcus aureus are important causative agents of hospital-acquired infections and bacteremia, likely due to their ability to form biofilms. The production of a dense exopolysaccharide (EPS) matrix enclosing the cells slows the penetration of antibiotic down, resulting in therapy failure. The EPS depolymerase (Dpo7) derived from bacteriophage vB_SepiS-phiIPLA7, was overexpressed in Escherichia coli and characterized. A dose dependent but time independent response was observed after treatment of staphylococcal 24 h-biofilms with Dpo7. Maximum removal (>90%) of biofilm-attached cells was obtained with 0.15 μM of Dpo7 in all polysaccharide producer strains but Dpo7 failed to eliminate polysaccharide-independent biofilm formed by S. aureus V329. Moreover, the pre-treatment of polystyrene surfaces with Dpo7 reduced the biofilm biomass by 53–85% in the 67% of the tested strains. This study supports the use of phage-encoded EPS depolymerases to prevent and disperse staphylococcal biofilms, thereby making bacteria more susceptible to the action of antimicrobials. PMID:26635776

  13. Tree species effects on pathogen-suppressive capacities of soil bacteria across two tropical dry forests in Costa Rica.

    PubMed

    Becklund, Kristen; Powers, Jennifer; Kinkel, Linda

    2016-11-01

    Antibiotic-producing bacteria in the genus Streptomyces can inhibit soil-borne plant pathogens, and have the potential to mediate the impacts of disease on plant communities. Little is known about how antibiotic production varies among soil communities in tropical forests, despite a long history of interest in the role of soil-borne pathogens in these ecosystems. Our objective was to determine how tree species and soils influence variation in antibiotic-mediated pathogen suppression among Streptomyces communities in two tropical dry forest sites (Santa Rosa and Palo Verde). We targeted tree species that co-occur in both sites and used a culture-based functional assay to quantify pathogen-suppressive capacities of Streptomyces communities beneath 50 focal trees. We also measured host-associated litter and soil element concentrations as potential mechanisms by which trees may influence soil microbes. Pathogen-suppressive capacities of Streptomyces communities varied within and among tree species, and inhibitory phenotypes were significantly related to soil and litter element concentrations. Average proportions of inhibitory Streptomyces in soils from the same tree species varied between 1.6 and 3.3-fold between sites. Densities and proportions of pathogen-suppressive bacteria were always higher in Santa Rosa than Palo Verde. Our results suggest that spatial heterogeneity in the potential for antibiotic-mediated disease suppression is shaped by tree species, site, and soil characteristics, which could have significant implications for understanding plant community composition and diversity in tropical dry forests.

  14. Sensitive and rapid RT-qPCR quantification of pathogenic Candida species in human blood.

    PubMed

    Ogata, Kiyohito; Matsuda, Kazunori; Tsuji, Hirokazu; Nomoto, Koji

    2015-10-01

    For accurate diagnosis and appropriate treatment of candidiasis, we developed a highly sensitive quantitative RT-PCR (RT-qPCR) system for five Candida species that have been reported to be the major causes of bloodstream fungal infection (Candida albicans, Candida glabrata, Candida tropicalis, Candida parapsilosis, and Candida krusei), together with a system for all pathogenic Candida species. Cells of each fungal species spiked into human peripheral blood (PB) were specifically detected at a lower detection limit of 10(0) cell/1 mL PB by this system using the newly developed specific primer sets targeting 18S or 26S rRNA of the five Candida species, together with the existing group primer set. The total count of the five Candida spp. as the sum of those obtained by using the five species primer sets was equivalent to the count obtained by using the group primer set, indicating that the group set covered the major five Candida spp. in human blood with the same degree of accuracy as the species primer sets. The RT-qPCR counts of the Candida species were in good agreement with CFU counts obtained by their culture on CHROMagar™, with a lower detection limit of 10(0)cell/mL of PB. Candida rRNA molecules were stably stored for at least 7 days at 4°C by keeping the blood specimens in an RNA stabilizing reagent. These results strongly suggest that this sensitive system is useful for accurate and rapid diagnosis of Candida bloodstream infections.

  15. SPECIES-SPECIFIC DETECTION OF THREE HUMAN-PATHOGENIC MICROSPORIDIAL SPECIES FROM THE GENUS ENCEPHALITOZOON VIA FLUOROGENIC 5' NUCLEASE PCR ASSAYS

    EPA Science Inventory

    This describes fluorogenic 5' nuclease PCR assays suitable for rapid, sensitive, quantitative, high-throughput detection of the human-pathogenic microsporidial species Encephalitozoon hellem, E. cunicli and E. intestinalis. The assays utilize species-specific primer sets and a g...

  16. [Staphylococcal epidermal exfoliation (Ritter's disease)].

    PubMed

    Ruiz Maldonado, R; Tamayo, L; Vazquez, V; Dominguez, J

    1976-01-01

    According to the authors the best designation of Ritter's disease would be "staphilococcic epidermal exfoliation" SEE. The physiopathological and agnoslogical basis for this denomination could be the following: 1st The "S. aureus" is the ehtiological agent of the SSE in man. The Koch postulates necessary to confirm this hypothesis have been accomplished. 2nd "Staphylococcus aureus" produces a thermostable toxin that is active indepently of the staphilococcus and gives rise to the separation of the cells of the stratum granulosus of the epidermis and eventually exfoliation in suckling babies and in the newborn mouse. 3rd The "Staphylococcus aureus" may be present on the skin or in other localisations such as the bowel or pharinx. 4th The viable "S. aureus" when administered subcutaneously to the adult mice gives rise to lesions clinically and histologically similar to the impetigo observed in children. 5th The "S. aureus" killed by means of autoclave (that is, the staphylococcic toxine by itself does not give rise to any lesion when administered to the healthy adult mouse). Neijther has the SEE been observed in healthy adult man. The authors reach the conclusion that the SSE and the toxic epidermal necrolysis are basically different according to the histopathology therapeutic response and prognosis and they must be considered as independant entities. PMID:138775

  17. Comparison of the rhamnomannans from the human pathogen Sporothrix schenckii with those from the Ceratocystis species.

    PubMed

    Travassos, L R; Gorin, P A; Lloyd, K O

    1973-11-01

    Rhamnomannans from several isolates of Sporothrix schenckii and Ceratocystis species were compared. No major differences emerged in the analysis of the carbohydrate composition of polysaccharides from either species. Methylation analysis for the identification of the glycosidic linkages present in the polysaccharides showed that they all were very similar with minor differences being observed among strains and between polysaccharides obtained at 25 and 37 C. Partially methylated derivatives were identified by gas-liquid chromatography and mass spectrometry. Their proportions suggest that polysaccharides from S. schenckii and C. stenoceras have a general structure similar to that of C. ulmi: a (1 --> 6)-linked alpha-d-mannopyranosyl main chain substituted in the 3-positions by alpha-l-rhamnopyranosyl and in many cases by alpha-l-rhamnopyranosyl (1-->2)-l-rhamnopyranosyl side chains. Differences among polysaccharides resided in the proportions of the dirhamnosyl side chains and of 4-O-substituted and 2, 4-di-O-substituted mannose units. Increased proportions of dirhamnosyl side chains were observed in the polysaccharides from S. schenckii strains and from a pathogenic variant of C. stenoceras grown at 25 C. Proton magnetic resonance spectra (H-1 region) of the rhamnomannans showed that S. schenckii strains could be placed in two different groups similar but not identical to any Ceratocystis species. These spectra were very close to those of the polysaccharides from the C. clavata and C. ambrosia groups of Ceratocystis species.

  18. Investigating differences across host species and scales to explain the distribution of the amphibian pathogen Batrachochytrium dendrobatidis.

    PubMed

    Peterson, Anna C; McKenzie, Valerie J

    2014-01-01

    Many pathogens infect more than one host species, and clarifying how these different hosts contribute to pathogen dynamics can facilitate the management of pathogens and can lend insight into the functioning of pathogens in ecosystems. In this study, we investigated a suite of native and non-native amphibian hosts of the pathogen Batrachochytrium dendrobatidis (Bd) across multiple scales to identify potential mechanisms that may drive infection patterns in the Colorado study system. Specifically, we aimed to determine if: 1) amphibian populations vary in Bd infection across the landscape, 2) amphibian community composition predicts infection (e.g., does the presence or abundance of any particular species influence infection in others?), 3) amphibian species vary in their ability to produce infectious zoospores in a laboratory infection, 4) heterogeneity in host ability observed in the laboratory scales to predict patterns of Bd prevalence in the landscape. We found that non-native North American bullfrogs (Lithobates catesbeianus) are widespread and have the highest prevalence of Bd infection relative to the other native species in the landscape. Additionally, infection in some native species appears to be related to the density of sympatric L. catesbeianus populations. At the smaller host scale, we found that L. catesbeianus produces more of the infective zoospore stage relative to some native species, but that this zoospore output does not scale to predict infection in sympatric wild populations of native species. Rather, landscape level infection relates most strongly to density of hosts at a wetland as well as abiotic factors. While non-native L. catesbeianus have high levels of Bd infection in the Colorado Front Range system, we also identified Bd infection in a number of native amphibian populations allopatric with L. catesbeianus, suggesting that multiple host species are important contributors to the dynamics of the Bd pathogen in this landscape. PMID

  19. Investigating Differences across Host Species and Scales to Explain the Distribution of the Amphibian Pathogen Batrachochytrium dendrobatidis

    PubMed Central

    Peterson, Anna C.; McKenzie, Valerie J.

    2014-01-01

    Many pathogens infect more than one host species, and clarifying how these different hosts contribute to pathogen dynamics can facilitate the management of pathogens and can lend insight into the functioning of pathogens in ecosystems. In this study, we investigated a suite of native and non-native amphibian hosts of the pathogen Batrachochytrium dendrobatidis (Bd) across multiple scales to identify potential mechanisms that may drive infection patterns in the Colorado study system. Specifically, we aimed to determine if: 1) amphibian populations vary in Bd infection across the landscape, 2) amphibian community composition predicts infection (e.g., does the presence or abundance of any particular species influence infection in others?), 3) amphibian species vary in their ability to produce infectious zoospores in a laboratory infection, 4) heterogeneity in host ability observed in the laboratory scales to predict patterns of Bd prevalence in the landscape. We found that non-native North American bullfrogs (Lithobates catesbeianus) are widespread and have the highest prevalence of Bd infection relative to the other native species in the landscape. Additionally, infection in some native species appears to be related to the density of sympatric L. catesbeianus populations. At the smaller host scale, we found that L. catesbeianus produces more of the infective zoospore stage relative to some native species, but that this zoospore output does not scale to predict infection in sympatric wild populations of native species. Rather, landscape level infection relates most strongly to density of hosts at a wetland as well as abiotic factors. While non-native L. catesbeianus have high levels of Bd infection in the Colorado Front Range system, we also identified Bd infection in a number of native amphibian populations allopatric with L. catesbeianus, suggesting that multiple host species are important contributors to the dynamics of the Bd pathogen in this landscape. PMID

  20. Changes in Caenorhabditis elegans immunity and Staphylococcal virulence factors during their interactions.

    PubMed

    JebaMercy, Gnanasekaran; Prithika, Udayakumar; Lavanya, Nehru; Sekar, Chinnathambi; Balamurugan, Krishnaswamy

    2015-03-01

    The nematode Caenorhabditis elegans is used as a model system for the study of host-pathogen interactions. Lipoteichoic acid (LTA) is one of the major virulent and immunostimulatory components found in gram positive bacteria. The current study used LTA isolated from Staphylococcus aureus and pathogenic and non-pathogenic Staphylococcus epidermidis. The overall physiological assays revealed that LTA exposed C. elegans show a significant reduction in the life span, production of eggs and progenies. To understand the involvement of innate immune specific players at the mRNA level, the regulation of few candidate antimicrobial genes was studied during Staphylococcal LTA exposures. qPCR analysis indicated an upregulation of antimicrobial peptides during LTA exposures. To understand the involvement of LTA and other virulent genes during infection, the regulation of LTA synthase and a few virulence genes was monitored during host exposure. The qPCR analyses indicated the upregulation of ltaS and other virulence genes (atoxin, sak, ssaA and fbe) during infection. Ability of the pathogens to modify their internal machinery during host presence was monitored by Fourier transform infrared spectroscopy, electrochemical impedance spectroscopy and cyclic voltametric analyses. The FTIR results indicated distinct alterations of peaks from Staphylococcal LTA composition between control and the host exposed. Further, EIS and CV data displayed clear differences between the host exposed Staphylococcal samples compared to their respective unexposed controls. The pathogenic and non-pathogenic strains showed different types of regulations and interactions during host exposures. The observed modifications clearly suggest that the Gram positive pathogen changes its LTA production and possibly the structure to cause a severe pathogenic effect on an interacting host.

  1. Phylogenetics and taxonomy of the fungal vascular wilt pathogen Verticillium, with the descriptions of five new species.

    PubMed

    Inderbitzin, Patrik; Bostock, Richard M; Davis, R Michael; Usami, Toshiyuki; Platt, Harold W; Subbarao, Krishna V

    2011-01-01

    Knowledge of pathogen biology and genetic diversity is a cornerstone of effective disease management, and accurate identification of the pathogen is a foundation of pathogen biology. Species names provide an ideal framework for storage and retrieval of relevant information, a system that is contingent on a clear understanding of species boundaries and consistent species identification. Verticillium, a genus of ascomycete fungi, contains important plant pathogens whose species boundaries have been ill defined. Using phylogenetic analyses, morphological investigations and comparisons to herbarium material and the literature, we established a taxonomic framework for Verticillium comprising ten species, five of which are new to science. We used a collection of 74 isolates representing much of the diversity of Verticillium, and phylogenetic analyses based on the ribosomal internal transcribed spacer region (ITS), partial sequences of the protein coding genes actin (ACT), elongation factor 1-alpha (EF), glyceraldehyde-3-phosphate dehydrogenase (GPD) and tryptophan synthase (TS). Combined analyses of the ACT, EF, GPD and TS datasets recognized two major groups within Verticillium, Clade Flavexudans and Clade Flavnonexudans, reflecting the respective production and absence of yellow hyphal pigments. Clade Flavexudans comprised V. albo-atrum and V. tricorpus as well as the new species V. zaregamsianum, V. isaacii and V. klebahnii, of which the latter two were morphologically indistinguishable from V. tricorpus but may differ in pathogenicity. Clade Flavnonexudans comprised V. nubilum, V. dahliae and V. longisporum, as well as the two new species V. alfalfae and V. nonalfalfae, which resembled the distantly related V. albo-atrum in morphology. Apart from the diploid hybrid V. longisporum, each of the ten species corresponded to a single clade in the phylogenetic tree comprising just one ex-type strain, thereby establishing a direct link to a name tied to a herbarium specimen

  2. Phylogenetics and Taxonomy of the Fungal Vascular Wilt Pathogen Verticillium, with the Descriptions of Five New Species

    PubMed Central

    Inderbitzin, Patrik; Bostock, Richard M.; Davis, R. Michael; Usami, Toshiyuki; Platt, Harold W.; Subbarao, Krishna V.

    2011-01-01

    Knowledge of pathogen biology and genetic diversity is a cornerstone of effective disease management, and accurate identification of the pathogen is a foundation of pathogen biology. Species names provide an ideal framework for storage and retrieval of relevant information, a system that is contingent on a clear understanding of species boundaries and consistent species identification. Verticillium, a genus of ascomycete fungi, contains important plant pathogens whose species boundaries have been ill defined. Using phylogenetic analyses, morphological investigations and comparisons to herbarium material and the literature, we established a taxonomic framework for Verticillium comprising ten species, five of which are new to science. We used a collection of 74 isolates representing much of the diversity of Verticillium, and phylogenetic analyses based on the ribosomal internal transcribed spacer region (ITS), partial sequences of the protein coding genes actin (ACT), elongation factor 1-alpha (EF), glyceraldehyde-3-phosphate dehydrogenase (GPD) and tryptophan synthase (TS). Combined analyses of the ACT, EF, GPD and TS datasets recognized two major groups within Verticillium, Clade Flavexudans and Clade Flavnonexudans, reflecting the respective production and absence of yellow hyphal pigments. Clade Flavexudans comprised V. albo-atrum and V. tricorpus as well as the new species V. zaregamsianum, V. isaacii and V. klebahnii, of which the latter two were morphologically indistinguishable from V. tricorpus but may differ in pathogenicity. Clade Flavnonexudans comprised V. nubilum, V. dahliae and V. longisporum, as well as the two new species V. alfalfae and V. nonalfalfae, which resembled the distantly related V. albo-atrum in morphology. Apart from the diploid hybrid V. longisporum, each of the ten species corresponded to a single clade in the phylogenetic tree comprising just one ex-type strain, thereby establishing a direct link to a name tied to a herbarium specimen

  3. Phylogenetics and taxonomy of the fungal vascular wilt pathogen Verticillium, with the descriptions of five new species.

    PubMed

    Inderbitzin, Patrik; Bostock, Richard M; Davis, R Michael; Usami, Toshiyuki; Platt, Harold W; Subbarao, Krishna V

    2011-01-01

    Knowledge of pathogen biology and genetic diversity is a cornerstone of effective disease management, and accurate identification of the pathogen is a foundation of pathogen biology. Species names provide an ideal framework for storage and retrieval of relevant information, a system that is contingent on a clear understanding of species boundaries and consistent species identification. Verticillium, a genus of ascomycete fungi, contains important plant pathogens whose species boundaries have been ill defined. Using phylogenetic analyses, morphological investigations and comparisons to herbarium material and the literature, we established a taxonomic framework for Verticillium comprising ten species, five of which are new to science. We used a collection of 74 isolates representing much of the diversity of Verticillium, and phylogenetic analyses based on the ribosomal internal transcribed spacer region (ITS), partial sequences of the protein coding genes actin (ACT), elongation factor 1-alpha (EF), glyceraldehyde-3-phosphate dehydrogenase (GPD) and tryptophan synthase (TS). Combined analyses of the ACT, EF, GPD and TS datasets recognized two major groups within Verticillium, Clade Flavexudans and Clade Flavnonexudans, reflecting the respective production and absence of yellow hyphal pigments. Clade Flavexudans comprised V. albo-atrum and V. tricorpus as well as the new species V. zaregamsianum, V. isaacii and V. klebahnii, of which the latter two were morphologically indistinguishable from V. tricorpus but may differ in pathogenicity. Clade Flavnonexudans comprised V. nubilum, V. dahliae and V. longisporum, as well as the two new species V. alfalfae and V. nonalfalfae, which resembled the distantly related V. albo-atrum in morphology. Apart from the diploid hybrid V. longisporum, each of the ten species corresponded to a single clade in the phylogenetic tree comprising just one ex-type strain, thereby establishing a direct link to a name tied to a herbarium specimen

  4. Pathogenic and saprophytic Leptospira species in water and soils from selected urban sites in peninsular Malaysia.

    PubMed

    Benacer, Douadi; Woh, Pei Yee; Mohd Zain, Siti Nursheena; Amran, Fairuz; Thong, Kwai Lin

    2013-01-01

    Leptospira species were studied in water and soils from selected urban sites in Malaysia. A total of 151 water (n=121) and soil (n=30) samples were collected from 12 recreational lakes and wet markets. All samples were filtered and inoculated into semi-solid Ellinghausen and McCullough modified by Johnson and Harris (EMJH) media supplemented with additional 5-fluorouracil. The cultures were then incubated at 30°C and observed under a dark field microscope with intervals of 10 days. A PCR assay targeting the rrs gene was used to confirm the genus Leptospira among the isolates. Subsequently, the pathogenic status of the isolates was determined using primer sets G1/G2 and Sapro1/Sapro2, which target the secY and rrs genes, respectively. The isolates were identified at serogroup level using the microscopic agglutination test (MAT) while their genetic diversity was assessed by pulsed field gel electrophoresis (PFGE). Based on dark field microscopy, 23.1% (28/121) water and 23.3% (7/30) soil cultures were positive for Leptospira spp. Of the 35 positive cultures, only 8 were pure and confirmed as Leptospira genus by PCR assay. Two out of 8 isolates were confirmed as pathogenic, 5 were saprophytic and one was intermediate. These 8 isolates were negative for the 25 reference hyperimmune rabbit sera tested in the MAT. PFGE showed that all 8 of these environmental Leptospira spp. were genetically diverse. In conclusion, the presence of pathogenic Leptospira spp. in the urban Malaysian environment may indicate and highlight the importance of water screening, especially in recreational lakes, in order to minimize any chance of Leptospira infection. PMID:23363618

  5. Predicting copper-, iron-, and zinc-binding proteins in pathogenic species of the Paracoccidioides genus

    PubMed Central

    Tristão, Gabriel B.; Assunção, Leandro do Prado; dos Santos, Luiz Paulo A.; Borges, Clayton L.; Silva-Bailão, Mirelle Garcia; Soares, Célia M. de Almeida; Cavallaro, Gabriele; Bailão, Alexandre M.

    2015-01-01

    Approximately one-third of all proteins have been estimated to contain at least one metal cofactor, and these proteins are referred to as metalloproteins. These represent one of the most diverse classes of proteins, containing metal ions that bind to specific sites to perform catalytic, regulatory and structural functions. Bioinformatic tools have been developed to predict metalloproteins encoded by an organism based only on its genome sequence. Its function and the type of metal binder can also be predicted via a bioinformatics approach. Paracoccidioides complex includes termodimorphic pathogenic fungi that are found as saprobic mycelia in the environment and as yeast, the parasitic form, in host tissues. They are the etiologic agents of Paracoccidioidomycosis, a prevalent systemic mycosis in Latin America. Many metalloproteins are important for the virulence of several pathogenic microorganisms. Accordingly, the present work aimed to predict the copper, iron and zinc proteins encoded by the genomes of three phylogenetic species of Paracoccidioides (Pb01, Pb03, and Pb18). The metalloproteins were identified using bioinformatics approaches based on structure, annotation and domains. Cu-, Fe-, and Zn-binding proteins represent 7% of the total proteins encoded by Paracoccidioides spp. genomes. Zinc proteins were the most abundant metalloproteins, representing 5.7% of the fungus proteome, whereas copper and iron proteins represent 0.3 and 1.2%, respectively. Functional classification revealed that metalloproteins are related to many cellular processes. Furthermore, it was observed that many of these metalloproteins serve as virulence factors in the biology of the fungus. Thus, it is concluded that the Cu, Fe, and Zn metalloproteomes of the Paracoccidioides spp. are of the utmost importance for the biology and virulence of these particular human pathogens. PMID:25620964

  6. Sequencing of the Litchi Downy Blight Pathogen Reveals It Is a Phytophthora Species With Downy Mildew-Like Characteristics.

    PubMed

    Ye, Wenwu; Wang, Yang; Shen, Danyu; Li, Delong; Pu, Tianhuizi; Jiang, Zide; Zhang, Zhengguang; Zheng, Xiaobo; Tyler, Brett M; Wang, Yuanchao

    2016-07-01

    On the basis of its downy mildew-like morphology, the litchi downy blight pathogen was previously named Peronophythora litchii. Recently, however, it was proposed to transfer this pathogen to Phytophthora clade 4. To better characterize this unusual oomycete species and important fruit pathogen, we obtained the genome sequence of Phytophthora litchii and compared it to those from other oomycete species. P. litchii has a small genome with tightly spaced genes. On the basis of a multilocus phylogenetic analysis, the placement of P. litchii in the genus Phytophthora is strongly supported. Effector proteins predicted included 245 RxLR, 30 necrosis-and-ethylene-inducing protein-like, and 14 crinkler proteins. The typical motifs, phylogenies, and activities of these effectors were typical for a Phytophthora species. However, like the genome features of the analyzed downy mildews, P. litchii exhibited a streamlined genome with a relatively small number of genes in both core and species-specific protein families. The low GC content and slight codon preferences of P. litchii sequences were similar to those of the analyzed downy mildews and a subset of Phytophthora species. Taken together, these observations suggest that P. litchii is a Phytophthora pathogen that is in the process of acquiring downy mildew-like genomic and morphological features. Thus P. litchii may provide a novel model for investigating morphological development and genomic adaptation in oomycete pathogens.

  7. Sequencing of the Litchi Downy Blight Pathogen Reveals It Is a Phytophthora Species With Downy Mildew-Like Characteristics.

    PubMed

    Ye, Wenwu; Wang, Yang; Shen, Danyu; Li, Delong; Pu, Tianhuizi; Jiang, Zide; Zhang, Zhengguang; Zheng, Xiaobo; Tyler, Brett M; Wang, Yuanchao

    2016-07-01

    On the basis of its downy mildew-like morphology, the litchi downy blight pathogen was previously named Peronophythora litchii. Recently, however, it was proposed to transfer this pathogen to Phytophthora clade 4. To better characterize this unusual oomycete species and important fruit pathogen, we obtained the genome sequence of Phytophthora litchii and compared it to those from other oomycete species. P. litchii has a small genome with tightly spaced genes. On the basis of a multilocus phylogenetic analysis, the placement of P. litchii in the genus Phytophthora is strongly supported. Effector proteins predicted included 245 RxLR, 30 necrosis-and-ethylene-inducing protein-like, and 14 crinkler proteins. The typical motifs, phylogenies, and activities of these effectors were typical for a Phytophthora species. However, like the genome features of the analyzed downy mildews, P. litchii exhibited a streamlined genome with a relatively small number of genes in both core and species-specific protein families. The low GC content and slight codon preferences of P. litchii sequences were similar to those of the analyzed downy mildews and a subset of Phytophthora species. Taken together, these observations suggest that P. litchii is a Phytophthora pathogen that is in the process of acquiring downy mildew-like genomic and morphological features. Thus P. litchii may provide a novel model for investigating morphological development and genomic adaptation in oomycete pathogens. PMID:27183038

  8. Phosphorus limitation, soil-borne pathogens and the coexistence of plant species in hyperdiverse forests and shrublands.

    PubMed

    Laliberté, Etienne; Lambers, Hans; Burgess, Treena I; Wright, S Joseph

    2015-04-01

    Hyperdiverse forests occur in the lowland tropics, whereas the most species-rich shrublands are found in regions such as south-western Australia (kwongan) and South Africa (fynbos). Despite large differences, these ecosystems share an important characteristic: their soils are strongly weathered and phosphorus (P) is a key growth-limiting nutrient. Soil-borne pathogens are increasingly being recognized as drivers of plant diversity in lowland tropical rainforests, but have received little attention in species-rich shrublands. We suggest a trade-off in which the species most proficient at acquiring P have ephemeral roots that are particularly susceptible to soil-borne pathogens. This could equalize out the differences in competitive ability among co-occurring species in these ecosystems, thus contributing to coexistence. Moreover, effective protection against soil-borne pathogens by ectomycorrhizal (ECM) fungi might explain the occurrence of monodominant stands of ECM trees and shrubs amongst otherwise species-rich communities. We identify gaps in our knowledge which need to be filled in order to evaluate a possible link between P limitation, fine root traits, soil-borne pathogens and local plant species diversity. Such a link may help to explain how numerous plant species can coexist in hyperdiverse rainforests and shrublands, and, conversely, how monodominant stands can develop in these ecosystems.

  9. Pythium phragmitis sp. nov., a new species close to P. arrhenomanes as a pathogen of common reed (Phragmites australis).

    PubMed

    Nechwatal, Jan; Wielgoss, Anna; Mendgen, Kurt

    2005-12-01

    During a study on the occurrence and pathogenicity of oomycetes in the reed-belt (Phragmites australis) of Lake Constance (Germany), a new Pythium resembling the important cereal pathogen species complex P. arrhenomanes/P. graminicola was consistently isolated from necrotic mature reed leaves and reed rhizosphere samples. The new species proved to be significantly more aggressive towards reed leaves and seedlings in vitro than related species. It is characterised by filamentous, inflated sporangia and plerotic oospores with usually more than one antheridium. ITS and cox II sequence data indicate this new species shares a common ancestor with P. arrhenomanes, but the sequence differences are clearly consistent with a divergence of the two taxa and with P. phragmitis being a distinct species. ITS 1 and 2 of 15 isolates of the taxon consistently differed from P. arrhenomanes by 13 positions. Sequence analyses of the cox II gene confirmed the new species' phylogenetic position. This paper gives a formal description of the taxon as P. phragmitis sp. nov., providing information on morphology, ecology and pathogenicity in comparison to related species. As indicated by the close association to Phragmites australis, the high aggressiveness towards reed leaves and seedlings, and the abundance in the investigated stands, Pythium phragmitis might act as a reed pathogen of considerable importance, in particular under flooding situations. PMID:16353634

  10. Diversity of Aquatic Pseudomonas Species and Their Activity against the Fish Pathogenic Oomycete Saprolegnia

    PubMed Central

    Liu, Yiying; Rzeszutek, Elzbieta; van der Voort, Menno; Wu, Cheng-Hsuan; Thoen, Even; Skaar, Ida; Bulone, Vincent; Dorrestein, Pieter C.; Raaijmakers, Jos M.; de Bruijn, Irene

    2015-01-01

    Emerging fungal and oomycete pathogens are increasingly threatening animals and plants globally. Amongst oomycetes, Saprolegnia species adversely affect wild and cultivated populations of amphibians and fish, leading to substantial reductions in biodiversity and food productivity. With the ban of several chemical control measures, new sustainable methods are needed to mitigate Saprolegnia infections in aquaculture. Here, PhyloChip-based community analyses showed that the Pseudomonadales, particularly Pseudomonas species, represent one of the largest bacterial orders associated with salmon eggs from a commercial hatchery. Among the Pseudomonas species isolated from salmon eggs, significantly more biosurfactant producers were retrieved from healthy salmon eggs than from Saprolegnia-infected eggs. Subsequent in vivo activity bioassays showed that Pseudomonas isolate H6 significantly reduced salmon egg mortality caused by Saprolegnia diclina. Live colony mass spectrometry showed that strain H6 produces a viscosin-like lipopeptide surfactant. This biosurfactant inhibited growth of Saprolegnia in vitro, but no significant protection of salmon eggs against Saprolegniosis was observed. These results indicate that live inocula of aquatic Pseudomonas strains, instead of their bioactive compound, can provide new (micro)biological and sustainable means to mitigate oomycete diseases in aquaculture. PMID:26317985

  11. Comparison of pathogenicity of Alternaria pellucida and Curvularia lunata on weed Echinochloa species.

    PubMed

    Reza, Mohammad; Motlagh, Safari

    2015-07-01

    Echinochloa spp. are the most important weeds in rice fields. In this research Curvularia lunata and Alternaria pellucida were isolated from these weeds and their pathogenicity effects were compared on these weeds and five rice cultivars in a completely random design with three replications in greenhouse conditions. Fungi were inoculated on weeds and rice cultivars, using spore suspension consisting of 10' spore ml(-1) of distilled water. Results indicated significant effect of Curvularia lunata and Alternaria pellucida on Echinochloa oryzicola and E. crus-galli. In the present study, effect of C. lunata on fresh weight, dry weight and height of Echinochloa species based on variance analysis table, a significant reaction was observed for height and fresh weight, but for dry weight reaction was not significant. The effect of A. pellucida on fresh weight, dry weight and height of Echinochloa species based on variance analysis table, a significant reaction was observed for all the three traits. Also, rice cultivars did not show any significant reaction to C. lunata and A. pellucida. The results showed that in comparison between effect of Curvularia lunata and Alternaria pellucida on Echinochloa spp., disease rating caused by A. pellucida on E. oryzicola and E. crusalli was more than disease rating caused by C. lunata and these species of weed were more susceptible to A. pellucida. However, A. alternata can be considered as a better promising bioherbicide to control Echinochloa spp.

  12. Seroepidemiologic Survey of Potential Pathogens in Obligate and Facultative Scavenging Avian Species in California.

    PubMed

    Straub, Mary H; Kelly, Terra R; Rideout, Bruce A; Eng, Curtis; Wynne, Janna; Braun, Josephine; Johnson, Christine K

    2015-01-01

    Throughout the world, populations of scavenger birds are declining rapidly with some populations already on the brink of extinction. Much of the current research into the factors contributing to these declines has focused on exposure to drug residues, lead, and other toxins. Despite increased monitoring of these declining populations, little is known about infectious diseases affecting scavenger bird species. To assess potential infectious disease risks to both obligate and facultative scavenger bird species, we performed a serosurvey for eleven potential pathogens in three species of scavenging birds in California: the California condor (Gymnogyps californianus), turkey vulture (Cathartes aura) and golden eagle (Aquila chrysaetos). California condors were seropositive for avian adenovirus, infectious bronchitis virus, Mycoplasma gallisepticum, avian paramyxovirus-2, West Nile virus (WNV) and Toxoplasma gondii. Golden eagles were seropositive for avian adenovirus, Chlamydophila psittaci and Toxoplasma gondii, and turkey vultures were seropositive for avian adenovirus, Chlamydophila psittaci, avian paramyxovirus-1, Toxoplasma gondii and WNV. Risk factor analyses indicated that rearing site and original release location were significantly associated with a positive serologic titer to WNV among free-flying condors. This study provides preliminary baseline data on infectious disease exposure in these populations for aiding in early disease detection and provides potentially critical information for conservation of the endangered California condor as it continues to expand its range and encounter new infectious disease threats.

  13. Seroepidemiologic Survey of Potential Pathogens in Obligate and Facultative Scavenging Avian Species in California

    PubMed Central

    Straub, Mary H.; Kelly, Terra R.; Rideout, Bruce A.; Eng, Curtis; Wynne, Janna; Braun, Josephine; Johnson, Christine K.

    2015-01-01

    Throughout the world, populations of scavenger birds are declining rapidly with some populations already on the brink of extinction. Much of the current research into the factors contributing to these declines has focused on exposure to drug residues, lead, and other toxins. Despite increased monitoring of these declining populations, little is known about infectious diseases affecting scavenger bird species. To assess potential infectious disease risks to both obligate and facultative scavenger bird species, we performed a serosurvey for eleven potential pathogens in three species of scavenging birds in California: the California condor (Gymnogyps californianus), turkey vulture (Cathartes aura) and golden eagle (Aquila chrysaetos). California condors were seropositive for avian adenovirus, infectious bronchitis virus, Mycoplasma gallisepticum, avian paramyxovirus-2, West Nile virus (WNV) and Toxoplasma gondii. Golden eagles were seropositive for avian adenovirus, Chlamydophila psittaci and Toxoplasma gondii, and turkey vultures were seropositive for avian adenovirus, Chlamydophila psittaci, avian paramyxovirus-1, Toxoplasma gondii and WNV. Risk factor analyses indicated that rearing site and original release location were significantly associated with a positive serologic titer to WNV among free-flying condors. This study provides preliminary baseline data on infectious disease exposure in these populations for aiding in early disease detection and provides potentially critical information for conservation of the endangered California condor as it continues to expand its range and encounter new infectious disease threats. PMID:26606755

  14. New species of Ophiocordyceps unilateralis, an ubiquitous pathogen of ants from Thailand.

    PubMed

    Kobmoo, Noppol; Mongkolsamrit, Suchada; Wutikhun, Taksadon; Tasanathai, Kanoksri; Khonsanit, Artit; Thanakitpipattana, Donnaya; Luangsa-Ard, Janet Jennifer

    2015-01-01

    Ophiocordyceps unilateralis is an ubiquitous pathogen of ants with hidden phylogenetic diversity associated with host specificity. In this study, we describe two new species to this species complex: Ophiocordyceps septa and Ophiocordyceps rami. Both were found on unidentified ants of the genus Camponotus (C. sp.1 and C. sp2 respectively). Ophiocordyceps septa is very similar to Ophiocordyceps polyrhachis-furcata, Ophiocordyceps camponoti-leonardi, and Ophiocordyceps camponoti-saundersi (found respectively on the ants Polyrhachis furcata, Camponotus leonardi, and Camponotus saundersi) but differs in the size, the shape and the septation of the ascospores, while O. rami is clearly identifiable with macro-morphological features including multiple stromata similar to Ophiocordyceps halabalaensis on Camponotus gigas. A thorough morphological examination was also provided for O. polyrhachis-furcata, O. camponoti-leonardi, and O. camponoti saundersi, showing that the first was apparently distinguishable from the others by the absence of septation of the ascospores. A combined molecular phylogeny also supports O. septa and O. rami as distinct new species.

  15. Myxozoan genera: definition and notes on taxonomy, life-cycle terminology and pathogenic species.

    PubMed

    Lom, Jirí; Dyková, Iva

    2006-03-01

    A list of myxozoan genera is presented in the current taxonomical scheme. These genera are defined; their type species and most important pathogens along with their hosts are listed. Simultaneously, definitions of actinospore stages representing sexual stages of the myxosporean life cycle are given; altogether, 17 actinospore collective groups with 180 types have been described. Life cycles of the two classes of the phylum Myxozoa, Malacosporea and Myxosporea, are briefly outlined with specification of the appropriate terms. Up to now, 4 malacosporean and 2,180 myxosporean species assigned to a total of 62 genera, have been established. The surviving classification of myxosporeans, based on spore morphology, is discussed in the context of the still fragmentary data resulting from SSU rDNA sequence analyses. The main task for the future is a rigorous, detailed morphological description combined with molecular techniques in establishment of new species and in revision of the existing ones. Establishment of a classification acceptable from morphological, biological and phylogenetical viewpoints is necessary.

  16. Screening of different Trichoderma species against agriculturally important foliar plant pathogens.

    PubMed

    Prabhakaran, Narayanasamy; Prameeladevi, Thokala; Sathiyabama, Muthukrishnan; Kamil, Deeba

    2015-01-01

    Different isolates of Trichoderma were isolated from soil samples which were collected from different part of India. These isolates were grouped into four Trichoderma species viz., Trichoderma asperellum (Ta), T. harzianum (Th), T. pseudokoningii (Tp) and T. longibrachiatum (Tl) based on their morphological characters. Identification of the above isolates was also confirmed through ITS region analysis. These Trichoderma isolates were tested for in vitro biological control of Alternaria solani, Bipolaris oryzae, Pyricularia oryzae and Sclerotinia scierotiorum which cause serious diseases like early blight (target spot) of tomato and potato, brown leaf spot disease in rice, rice blast disease, and white mold disease in different plants. Under in vitro conditions, all the four species of Trichoderma (10 isolates) proved 100% potential inhibition against rice blast pathogen Pyracularia oryzae. T. harzianum (Th-01) and T. asperellum (Ta-10) were effective with 86.6% and 97.7%, growth inhibition of B. oryzae, respectively. Among others, T. pseudokoningii (Tp-08) and T. Iongibrachiatum (Tl-09) species were particularly efficient in inhibiting growth of S. sclerotiorum by 97.8% and 93.3%. T. Iongibrachiatum (TI-06 and TI-07) inhibited maximum mycelial growth of A. solani by 87.6% and 84.75. However, all the T. harzianum isolates showed significantly higher inhibition against S. sclerotiorum (CD value 9.430), causing white mold disease. This study led to the selection of potential Trichoderma isolates against rice blast, early blight, brown leaf spot in rice and white mold disease in different crops. PMID:26536792

  17. Screening of different Trichoderma species against agriculturally important foliar plant pathogens.

    PubMed

    Prabhakaran, Narayanasamy; Prameeladevi, Thokala; Sathiyabama, Muthukrishnan; Kamil, Deeba

    2015-01-01

    Different isolates of Trichoderma were isolated from soil samples which were collected from different part of India. These isolates were grouped into four Trichoderma species viz., Trichoderma asperellum (Ta), T. harzianum (Th), T. pseudokoningii (Tp) and T. longibrachiatum (Tl) based on their morphological characters. Identification of the above isolates was also confirmed through ITS region analysis. These Trichoderma isolates were tested for in vitro biological control of Alternaria solani, Bipolaris oryzae, Pyricularia oryzae and Sclerotinia scierotiorum which cause serious diseases like early blight (target spot) of tomato and potato, brown leaf spot disease in rice, rice blast disease, and white mold disease in different plants. Under in vitro conditions, all the four species of Trichoderma (10 isolates) proved 100% potential inhibition against rice blast pathogen Pyracularia oryzae. T. harzianum (Th-01) and T. asperellum (Ta-10) were effective with 86.6% and 97.7%, growth inhibition of B. oryzae, respectively. Among others, T. pseudokoningii (Tp-08) and T. Iongibrachiatum (Tl-09) species were particularly efficient in inhibiting growth of S. sclerotiorum by 97.8% and 93.3%. T. Iongibrachiatum (TI-06 and TI-07) inhibited maximum mycelial growth of A. solani by 87.6% and 84.75. However, all the T. harzianum isolates showed significantly higher inhibition against S. sclerotiorum (CD value 9.430), causing white mold disease. This study led to the selection of potential Trichoderma isolates against rice blast, early blight, brown leaf spot in rice and white mold disease in different crops.

  18. Seroepidemiologic Survey of Potential Pathogens in Obligate and Facultative Scavenging Avian Species in California.

    PubMed

    Straub, Mary H; Kelly, Terra R; Rideout, Bruce A; Eng, Curtis; Wynne, Janna; Braun, Josephine; Johnson, Christine K

    2015-01-01

    Throughout the world, populations of scavenger birds are declining rapidly with some populations already on the brink of extinction. Much of the current research into the factors contributing to these declines has focused on exposure to drug residues, lead, and other toxins. Despite increased monitoring of these declining populations, little is known about infectious diseases affecting scavenger bird species. To assess potential infectious disease risks to both obligate and facultative scavenger bird species, we performed a serosurvey for eleven potential pathogens in three species of scavenging birds in California: the California condor (Gymnogyps californianus), turkey vulture (Cathartes aura) and golden eagle (Aquila chrysaetos). California condors were seropositive for avian adenovirus, infectious bronchitis virus, Mycoplasma gallisepticum, avian paramyxovirus-2, West Nile virus (WNV) and Toxoplasma gondii. Golden eagles were seropositive for avian adenovirus, Chlamydophila psittaci and Toxoplasma gondii, and turkey vultures were seropositive for avian adenovirus, Chlamydophila psittaci, avian paramyxovirus-1, Toxoplasma gondii and WNV. Risk factor analyses indicated that rearing site and original release location were significantly associated with a positive serologic titer to WNV among free-flying condors. This study provides preliminary baseline data on infectious disease exposure in these populations for aiding in early disease detection and provides potentially critical information for conservation of the endangered California condor as it continues to expand its range and encounter new infectious disease threats. PMID:26606755

  19. Diversity of Aquatic Pseudomonas Species and Their Activity against the Fish Pathogenic Oomycete Saprolegnia.

    PubMed

    Liu, Yiying; Rzeszutek, Elzbieta; van der Voort, Menno; Wu, Cheng-Hsuan; Thoen, Even; Skaar, Ida; Bulone, Vincent; Dorrestein, Pieter C; Raaijmakers, Jos M; de Bruijn, Irene

    2015-01-01

    Emerging fungal and oomycete pathogens are increasingly threatening animals and plants globally. Amongst oomycetes, Saprolegnia species adversely affect wild and cultivated populations of amphibians and fish, leading to substantial reductions in biodiversity and food productivity. With the ban of several chemical control measures, new sustainable methods are needed to mitigate Saprolegnia infections in aquaculture. Here, PhyloChip-based community analyses showed that the Pseudomonadales, particularly Pseudomonas species, represent one of the largest bacterial orders associated with salmon eggs from a commercial hatchery. Among the Pseudomonas species isolated from salmon eggs, significantly more biosurfactant producers were retrieved from healthy salmon eggs than from Saprolegnia-infected eggs. Subsequent in vivo activity bioassays showed that Pseudomonas isolate H6 significantly reduced salmon egg mortality caused by Saprolegnia diclina. Live colony mass spectrometry showed that strain H6 produces a viscosin-like lipopeptide surfactant. This biosurfactant inhibited growth of Saprolegnia in vitro, but no significant protection of salmon eggs against Saprolegniosis was observed. These results indicate that live inocula of aquatic Pseudomonas strains, instead of their bioactive compound, can provide new (micro)biological and sustainable means to mitigate oomycete diseases in aquaculture. PMID:26317985

  20. Partitiviruses of a fungal forest pathogen have species-specific quantities of genome segments and transcripts.

    PubMed

    Jurvansuu, Jaana; Kashif, Muhammad; Vaario, Leo; Vainio, Eeva; Hantula, Jarkko

    2014-08-01

    Heterobasidion partitiviruses infect forest pathogenic fungi of the genus Heterobasidion. We have studied the amounts of genomes and transcripts of four partitiviruses isolated from four different Heterobasidion strains infecting different host trees in Greece, Poland, Finland, and China. Heterobasidion partitiviruses have bisegmented genomes encoding coat protein and RNA-dependent RNA polymerase. Our results show that the coat protein genome segment is generally more abundant in infected mycelia than the RNA-dependent RNA polymerase segment and that this bias persists also at transcript levels. The different virus species all have unique ratios of the genome segments and the ratio is generally stable over different temperatures and hosts. The amounts of transcripts of each virus respond to host growth temperatures in a distinctive and consistent manner. The Heterobasidion partitiviruses studied here affect only rarely the growth of their natural hosts but do influence the growth of a new host more frequently.

  1. Rhodomyrtus tomentosa (Aiton) Hassk. leaf extract: An alternative approach for the treatment of staphylococcal bovine mastitis.

    PubMed

    Mordmuang, Auemphon; Voravuthikunchai, Supayang Piyawan

    2015-10-01

    Antibiotic residues in dairy products as well as emergence of antimicrobial resistance in foodborne pathogens have been recognized as global public health concerns. The present work was aimed to study a potent antibacterial extract from natural product as an alternative treatment for staphylococcal bovine mastitis. Staphylococcal isolates (n=44) were isolated from milk samples freshly squeezed from individual cows. All staphylococcal isolates were resistant to ampicillin, ciprofloxacin, erythromycin, gentamicin, penicillin, except vancomycin. Rhodomyrtus tomentosa leaf ethanolic extract was accessed for its antibacterial activity and anti-inflammatory potential. The extract exhibited profound antibacterial activity against all of staphylococcal isolates with MIC and MBC values ranged from 16-64 μg/ml and 64->128 μg/ml, respectively. Moreover, the extract also exerted anti-protein denaturation and human red blood cell membrane stabilizing activity. The results support the use of R. tomentosa extract that could be applied to cure bovine mastitis and to reduce inflammatory injury caused by the bacterial infections.

  2. Treatment of bullous impetigo and the staphylococcal scalded skin syndrome in infants.

    PubMed

    Johnston, Graham A

    2004-06-01

    Impetigo is a common, superficial, bacterial infection of the skin characterized by an inflamed and infected epidermis. The rarer variant, bullous impetigo, is characterized by fragile fluid-filled vesicles and flaccid blisters and is invariably caused by pathogenic strains of Staphylococcus aureus. Bullous impetigo is at the mild end of a spectrum of blistering skin diseases caused by a staphylococcal exfoliative toxin that, at the other extreme, is represented by widespread painful blistering and superficial denudation (the staphylococcal scalded skin syndrome). In bullous impetigo, the exfoliative toxins are restricted to the area of infection, and bacteria can be cultured from the blister contents. In staphylococcal scalded skin syndrome the exfoliative toxins are spread hematogenously from a localized source causing widespread epidermal damage at distant sites. Both occur more commonly in children under 5 years of age and particularly in neonates. It is important to swab the skin for bacteriological confirmation and antibiotic sensitivities and, in the case of staphylococcal scalded skin syndrome, to identify the primary focus of infection. Topical therapy should constitute either fusidic acid (Fucidin, Leo Pharma Ltd) as a first-line treatment, or mupirocin (Bactroban, GlaxoSmithKline) in proven cases of bacterial resistance. First-line systemic therapy is oral or intravenous flucloxacillin (Floxapen, GlaxoSmithKline). Nasal swabs from the patient and immediate relatives should be performed to identify asymptomatic nasal carriers of Staphylococcus aureus. In the case of outbreaks on wards and in nurseries, healthcare professionals should also be swabbed.

  3. Multi-locus tree and species tree approaches toward resolving a complex clade of downy mildews (Straminipila, Oomycota), including pathogens of beet and spinach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurate species determination of plant pathogens is a prerequisite for their control and quarantine, and further for assessing their potential threat to crops. The family Peronosporaceae (Straminipila; Oomycota) consists of obligate biotrophic pathogens that cause downy mildew disease on angiosperm...

  4. Cell shape dynamics during the staphylococcal cell cycle.

    PubMed

    Monteiro, João M; Fernandes, Pedro B; Vaz, Filipa; Pereira, Ana R; Tavares, Andreia C; Ferreira, Maria T; Pereira, Pedro M; Veiga, Helena; Kuru, Erkin; VanNieuwenhze, Michael S; Brun, Yves V; Filipe, Sérgio R; Pinho, Mariana G

    2015-08-17

    Staphylococcus aureus is an aggressive pathogen and a model organism to study cell division in sequential orthogonal planes in spherical bacteria. However, the small size of staphylococcal cells has impaired analysis of changes in morphology during the cell cycle. Here we use super-resolution microscopy and determine that S. aureus cells are not spherical throughout the cell cycle, but elongate during specific time windows, through peptidoglycan synthesis and remodelling. Both peptidoglycan hydrolysis and turgor pressure are required during division for reshaping the flat division septum into a curved surface. In this process, the septum generates less than one hemisphere of each daughter cell, a trait we show is common to other cocci. Therefore, cell surface scars of previous divisions do not divide the cells in quadrants, generating asymmetry in the daughter cells. Our results introduce a need to reassess the models for division plane selection in cocci.

  5. Discord between morphological and phylogenetic species boundaries: incomplete lineage sorting and recombination results in fuzzy species boundaries in an asexual fungal pathogen

    PubMed Central

    2014-01-01

    Background Traditional morphological and biological species concepts are difficult to apply to closely related, asexual taxa because of the lack of an active sexual phase and paucity of morphological characters. Phylogenetic species concepts such as genealogical concordance phylogenetic species recognition (GCPSR) have been extensively used; however, methods that incorporate gene tree uncertainty into species recognition may more accurately and objectively delineate species. Using a worldwide sample of Alternaria alternata sensu lato, causal agent of citrus brown spot, the evolutionary histories of four nuclear loci including an endo-polygalacturonase gene, two anonymous loci, and one microsatellite flanking region were estimated using the coalescent. Species boundaries were estimated using several approaches including those that incorporate uncertainty in gene genealogies when lineage sorting and non-reciprocal monophyly of gene trees is common. Results Coalescent analyses revealed three phylogenetic lineages strongly influenced by incomplete lineage sorting and recombination. Divergence of the citrus 2 lineage from the citrus 1 and citrus 3 lineages was supported at most loci. A consensus of species tree estimation methods supported two species of Alternaria causing citrus brown spot worldwide. Based on substitution rates at the endo-polygalacturonase locus, divergence of the citrus 2 and the 1 and 3 lineages was estimated to have occurred at least 5, 400 years before present, predating the human-mediated movement of citrus and associated pathogens out of SE Asia. Conclusions The number of Alternaria species identified as causing brown spot of citrus worldwide using morphological criteria has been overestimated. Little support was found for most of these morphospecies using quantitative species recognition approaches. Correct species delimitation of plant-pathogenic fungi is critical for understanding the evolution of pathogenicity, introductions of pathogens to

  6. Rapid Identification of Emerging Human-Pathogenic Sporothrix Species with Rolling Circle Amplification

    PubMed Central

    Rodrigues, Anderson M.; Najafzadeh, Mohammad J.; de Hoog, G. Sybren; de Camargo, Zoilo P.

    2015-01-01

    Sporothrix infections are emerging as an important human and animal threat among otherwise healthy patients, especially in Brazil and China. Correct identification of sporotrichosis agents is beneficial for epidemiological surveillance, enabling implementation of adequate public-health policies and guiding antifungal therapy. In areas of limited resources where sporotrichosis is endemic, high-throughput detection methods that are specific and sensitive are preferred over phenotypic methods that usually result in misidentification of closely related Sporothrix species. We sought to establish rolling circle amplification (RCA) as a low-cost screening tool for species-specific identification of human-pathogenic Sporothrix. We developed six species-specific padlock probes targeting polymorphisms in the gene encoding calmodulin. BLAST-searches revealed candidate probes that were conserved intraspecifically; no significant homology with sequences from humans, mice, plants or microorganisms outside members of Sporothrix were found. The accuracy of our RCA-based assay was demonstrated through the specificity of probe-template binding to 25 S. brasiliensis, 58 S. schenckii, 5 S. globosa, 1 S. luriei, 4 S. mexicana, and 3 S. pallida samples. No cross reactivity between closely related species was evident in vitro, and padlock probes yielded 100% specificity and sensitivity down to 3 × 106 copies of the target sequence. RCA-based speciation matched identifications via phylogenetic analysis of the gene encoding calmodulin and the rDNA operon (kappa 1.0; 95% confidence interval 1.0-1.0), supporting its use as a reliable alternative to DNA sequencing. This method is a powerful tool for rapid identification and specific detection of medically relevant Sporothrix, and due to its robustness has potential for ecological studies. PMID:26696992

  7. Rapid Identification of Emerging Human-Pathogenic Sporothrix Species with Rolling Circle Amplification.

    PubMed

    Rodrigues, Anderson M; Najafzadeh, Mohammad J; de Hoog, G Sybren; de Camargo, Zoilo P

    2015-01-01

    Sporothrix infections are emerging as an important human and animal threat among otherwise healthy patients, especially in Brazil and China. Correct identification of sporotrichosis agents is beneficial for epidemiological surveillance, enabling implementation of adequate public-health policies and guiding antifungal therapy. In areas of limited resources where sporotrichosis is endemic, high-throughput detection methods that are specific and sensitive are preferred over phenotypic methods that usually result in misidentification of closely related Sporothrix species. We sought to establish rolling circle amplification (RCA) as a low-cost screening tool for species-specific identification of human-pathogenic Sporothrix. We developed six species-specific padlock probes targeting polymorphisms in the gene encoding calmodulin. BLAST-searches revealed candidate probes that were conserved intraspecifically; no significant homology with sequences from humans, mice, plants or microorganisms outside members of Sporothrix were found. The accuracy of our RCA-based assay was demonstrated through the specificity of probe-template binding to 25 S. brasiliensis, 58 S. schenckii, 5 S. globosa, 1 S. luriei, 4 S. mexicana, and 3 S. pallida samples. No cross reactivity between closely related species was evident in vitro, and padlock probes yielded 100% specificity and sensitivity down to 3 × 10(6) copies of the target sequence. RCA-based speciation matched identifications via phylogenetic analysis of the gene encoding calmodulin and the rDNA operon (kappa 1.0; 95% confidence interval 1.0-1.0), supporting its use as a reliable alternative to DNA sequencing. This method is a powerful tool for rapid identification and specific detection of medically relevant Sporothrix, and due to its robustness has potential for ecological studies. PMID:26696992

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

    PubMed Central

    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. PMID:27812511

  9. Laboratory evaluation of pathogenicity of entomogenous nematodes to African tick species.

    PubMed

    Kaaya, G P; Samish, M; Glazer, I

    2000-01-01

    Five strains of entomogenous nematodes, Steinernema carpocapsae strains DD, Mexican, SR, and Heterorhabditis bacteriophora strains 1S5 and HP88, were tested for their pathogenicity to various developmental stages of five African tick species namely; Rhipicephalus appendiculatus, R. evertsi, Amblyomma variegatum, A. gemma, and Boophilus decoloratus. In engorged female R. appendiculatus, all nematodes at a concentration of 1,000 infective juveniles (IJ)/dish, except S. carpocapsae Mexican strain, induced high mortalities (56-100%), whereas in engorged female R. evertsi, only S. carpocapsae DD and H. bacteriophora HP88 induced high mortalities (78% and 56%, respectively). In engorged B. decoloratus, S. carpocapsae DD, Mexican, SR and H. bacteriophora HP88 (100 IJ/dish) induced mortalities of 85%, 65%, 80%, and 100%, respectively. In all cases, except for S. carpocapsae Mexican strain, a higher concentration (5,000 IJ/dish) did not result in higher mortality than occurred with 1,000 IJ/dish. Unfed females and immature stages of ticks were found to be generally resistant to the nematodes. The feasibility of using entomogenous nematodes for biological control of African tick species are briefly discussed. PMID:11193637

  10. Pathogenicity in six Australian reptile species following experimental inoculation with Bohle iridovirus.

    PubMed

    Ariel, E; Wirth, W; Burgess, G; Scott, J; Owens, L

    2015-08-20

    Ranaviruses are able to infect multiple species of fish, amphibian and reptile, and some strains are capable of interclass transmission. These numerous potential carriers and reservoir species compound efforts to control and contain infections in cultured and wild populations, and a comprehensive knowledge of susceptible species and life stage is necessary to inform such processes. Here we report on the challenge of 6 water-associated reptiles with Bohle iridovirus (BIV) to investigate its potential pathogenicity in common native reptiles of the aquatic and riparian fauna of northern Queensland, Australia. Adult tortoises Elseya latisternum and Emydura krefftii, snakes Boiga irregularis, Dendrelaphis punctulatus and Amphiesma mairii, and yearling crocodiles Crocodylus johnstoni were exposed via intracoelomic inoculation or co-habitation with infected con-specifics, but none were adversely affected by the challenge conditions applied here. Bohle iridovirus was found to be extremely virulent in hatchling tortoises E. latisternum and E. krefftii via intracoelomic challenge, as demonstrated by distinct lesions in multiple organs associated with specific immunohistochemistry staining and a lethal outcome (10/17) of the challenge. Virus was re-isolated from 2/5 E. latisternum, 4/12 E. krefftii and 1/3 brown tree snakes B. irregularis. Focal necrosis, haemorrhage and infiltration of granulocytes were frequently observed histologically in the pancreas, liver and sub-mucosa of the intestine of challenged tortoise hatchlings. Immunohistochemistry demonstrated the presence of ranavirus antigens in the necrotic lesions and in individual cells of the vascular endothelium, the connective tissue and in granulocytes associated with necrosis or present along serosal surfaces. The outcome of this study confirms hatchling tortoises are susceptible to BIV, thereby adding Australian reptiles to the host range of ranaviruses. Additionally, given that BIV was originally isolated from an

  11. Genome-Wide Identification and Comprehensive Analyses of the Kinomes in Four Pathogenic Microsporidia Species

    PubMed Central

    Li, Zhi; Hao, Youjin; Wang, Linling; Xiang, Heng; Zhou, Zeyang

    2014-01-01

    Microsporidia have attracted considerable attention because they infect a wide range of hosts, from invertebrates to vertebrates, and cause serious human diseases and major economic losses in the livestock industry. There are no prospective drugs to counteract this pathogen. Eukaryotic protein kinases (ePKs) play a central role in regulating many essential cellular processes and are therefore potential drug targets. In this study, a comprehensive summary and comparative analysis of the protein kinases in four microsporidia–Enterocytozoon bieneusi, Encephalitozoon cuniculi, Nosema bombycis and Nosema ceranae–was performed. The results show that there are 34 ePKs and 4 atypical protein kinases (aPKs) in E. bieneusi, 29 ePKs and 6 aPKs in E. cuniculi, 41 ePKs and 5 aPKs in N. bombycis, and 27 ePKs and 4 aPKs in N. ceranae. These data support the previous conclusion that the microsporidian kinome is the smallest eukaryotic kinome. Microsporidian kinomes contain only serine-threonine kinases and do not contain receptor-like and tyrosine kinases. Many of the kinases related to nutrient and energy signaling and the stress response have been lost in microsporidian kinomes. However, cell cycle-, development- and growth-related kinases, which are important to parasites, are well conserved. This reduction of the microsporidian kinome is in good agreement with genome compaction, but kinome density is negatively correlated with proteome size. Furthermore, the protein kinases in each microsporidian genome are under strong purifying selection pressure. No remarkable differences in kinase family classification, domain features, gain and/or loss, and selective pressure were observed in these four species. Although microsporidia adapt to different host types, the coevolution of microsporidia and their hosts was not clearly reflected in the protein kinases. Overall, this study enriches and updates the microsporidian protein kinase database and may provide valuable information and

  12. Influence of pathogenic bacteria species present in the postpartum bovine uterus on proteome profiles.

    PubMed

    Ledgard, A M; Smolenski, G A; Henderson, H; Lee, R S F

    2015-01-01

    In the first 2-3 weeks after parturition >90% of dairy cows will have some form of uterine infection. Uterine contamination with pathogens, such as Trueperella (formerly Arcanobacterium) pyogenes increases the risk of developing more severe endometritis, which can reduce conception rates. In this study, we compared the uterine proteome of cows infected with Trueperella pyogenes with that of uninfected cows, using 2D gel electrophoresis, and identified annexins A1 and A2 (ANXA1 and ANXA2), apolipoprotein A-1, calprotectin (S100A9), cathelicidin, enolase 1 (ENO1), peptidoglycan recognition protein 1 (PGLYRP1), phosphoglycerate mutase 1 (PGAM1), serine dehydratase (SDS) and serine protease inhibitors (SERPIN) B1, B3 and B4 proteins as differing in abundance in endometritis. Subsequently, levels of ten of these proteins were monitored in uterine samples collected from a herd of lactating, dairy cows at 15 and 42 days post-partum (DPP). The levels were compared with the cytology scores of the samples and the bacterial species isolated from the uterus. Cathelicidin, PGLYRP1, SERPINB1 and S100A9 levels at 15DPP showed strong positive correlations (r=0.78, 0.80, 0.79, and 0.68 respectively; P<0.001) with % of polymorphonuclear neutrophils (PMN). When compared with other bacterial pathogens identified, Streptococcus agalactiae and Truperella pyogenes induced increased expression of the indicator proteins, suggesting that these organisms may adversely affect the subsequent ability of the cow to conceive. Interestingly, there was no difference in the proportion of cows pregnant at 6 and 17 weeks after start of mating between the cows with high or low %PMN. PMID:24331367

  13. Insertional Inactivation of eap in Staphylococcus aureus Strain Newman Confers Reduced Staphylococcal Binding to Fibroblasts

    PubMed Central

    Hussain, Muzaffar; Haggar, Axana; Heilmann, Christine; Peters, Georg; Flock, Jan-Ingmar; Herrmann, Mathias

    2002-01-01

    . In conclusion, Eap may contribute to pathogenicity by promoting adhesion of whole staphylococcal cells to complex eukaryotic substrates. PMID:12010982

  14. Insertional inactivation of Eap in Staphylococcus aureus strain Newman confers reduced staphylococcal binding to fibroblasts.

    PubMed

    Hussain, Muzaffar; Haggar, Axana; Heilmann, Christine; Peters, Georg; Flock, Jan-Ingmar; Herrmann, Mathias

    2002-06-01

    . In conclusion, Eap may contribute to pathogenicity by promoting adhesion of whole staphylococcal cells to complex eukaryotic substrates.

  15. Effect of species, breed and route of virus inoculation on the pathogenicity of H5N1 highly pathogenic influenza (HPAI) viruses in domestic ducks

    PubMed Central

    2013-01-01

    H5N1 highly pathogenic avian influenza (HPAI) viruses continue to be a threat to poultry in many regions of the world. Domestic ducks have been recognized as one of the primary factors in the spread of H5N1 HPAI. In this study we examined the pathogenicity of H5N1 HPAI viruses in different species and breeds of domestic ducks and the effect of route of virus inoculation on the outcome of infection. We determined that the pathogenicity of H5N1 HPAI viruses varies between the two common farmed duck species, with Muscovy ducks (Cairina moschata) presenting more severe disease than various breeds of Anas platyrhynchos var. domestica ducks including Pekin, Mallard-type, Black Runners, Rouen, and Khaki Campbell ducks. We also found that Pekin and Muscovy ducks inoculated with two H5N1 HPAI viruses of different virulence, given by any one of three routes (intranasal, intracloacal, or intraocular), became infected with the viruses. Regardless of the route of inoculation, the outcome of infection was similar for each species but depended on the virulence of the virus used. Muscovy ducks showed more severe clinical signs and higher mortality than the Pekin ducks. In conclusion, domestic ducks are susceptible to H5N1 HPAI virus infection by different routes of exposure, but the presentation of the disease varied by virus strain and duck species. This information helps support the planning and implementation of H5N1 HPAI surveillance and control measures in countries with large domestic duck populations. PMID:23876184

  16. Effect of species, breed and route of virus inoculation on the pathogenicity of H5N1 highly pathogenic influenza (HPAI) viruses in domestic ducks.

    PubMed

    Pantin-Jackwood, Mary; Swayne, David E; Smith, Diane; Shepherd, Eric

    2013-07-22

    H5N1 highly pathogenic avian influenza (HPAI) viruses continue to be a threat to poultry in many regions of the world. Domestic ducks have been recognized as one of the primary factors in the spread of H5N1 HPAI. In this study we examined the pathogenicity of H5N1 HPAI viruses in different species and breeds of domestic ducks and the effect of route of virus inoculation on the outcome of infection. We determined that the pathogenicity of H5N1 HPAI viruses varies between the two common farmed duck species, with Muscovy ducks (Cairina moschata) presenting more severe disease than various breeds of Anas platyrhynchos var. domestica ducks including Pekin, Mallard-type, Black Runners, Rouen, and Khaki Campbell ducks. We also found that Pekin and Muscovy ducks inoculated with two H5N1 HPAI viruses of different virulence, given by any one of three routes (intranasal, intracloacal, or intraocular), became infected with the viruses. Regardless of the route of inoculation, the outcome of infection was similar for each species but depended on the virulence of the virus used. Muscovy ducks showed more severe clinical signs and higher mortality than the Pekin ducks. In conclusion, domestic ducks are susceptible to H5N1 HPAI virus infection by different routes of exposure, but the presentation of the disease varied by virus strain and duck species. This information helps support the planning and implementation of H5N1 HPAI surveillance and control measures in countries with large domestic duck populations.

  17. Efficiency of rep-PCR fingerprinting as a useful technique for molecular typing of plant pathogenic fungal species: Botryosphaeriaceae species as a case study.

    PubMed

    Abdollahzadeh, Jafar; Zolfaghari, Sajedeh

    2014-12-01

    Progress in molecular biology and the advent of rapid and accurate molecular techniques have contributed to precise and rapid detection and differentiation of microbial pathogens. Identification of the Botryosphaeriaceae species based on morphology has been problematic over time. In this study, we used rep-PCR technique as a molecular tool for typing and differentiation of the Botryosphaeriaceae species, well-known and cosmopolitan fungal pathogens on woody plants. Three primer sets BOX, ERIC and REP were used to differentiate 27 species belong to eight genera. The majority of them were examined in terms of typing and differentiation using molecular methods for the first time. All the primer sets were able to generate species-specific DNA fingerprints from all the tested strains, with two exceptions in the genera Diplodia and Spencermartinsia. Despite the deficiency of each primer sets to separate a few species, cluster analysis of combined data sets indicated the ability of rep-PCR technique to separate 26 out of 27 examined species in highly supported clusters corresponded to the species recognized based on DNA sequence data. Our findings revealed the efficiency of rep-PCR for detection and differentiation of the Botryosphaeriaceae species, especially cryptic species with the same ITS sequences and similar morphology.

  18. Staphylococcal proteases aid in evasion of the human complement system.

    PubMed

    Jusko, Monika; Potempa, Jan; Kantyka, Tomasz; Bielecka, Ewa; Miller, Halie K; Kalinska, Magdalena; Dubin, Grzegorz; Garred, Peter; Shaw, Lindsey N; Blom, Anna M

    2014-01-01

    Staphylococcus aureus is an opportunistic pathogen that presents severe health care concerns due to the prevalence of multiple antibiotic-resistant strains. New treatment strategies are urgently needed, which requires an understanding of disease causation mechanisms. Complement is one of the first lines of defense against bacterial pathogens, and S. aureus expresses several specific complement inhibitors. The effect of extracellular proteases from this bacterium on complement, however, has been the subject of limited investigation, except for a recent report regarding cleavage of the C3 component by aureolysin (Aur). We demonstrate here that four major extracellular proteases of S. aureus are potent complement inhibitors. Incubation of human serum with the cysteine proteases staphopain A and staphopain B, the serine protease V8 and the metalloproteinase Aur resulted in a drastic decrease in the hemolytic activity of serum, whereas two staphylococcal serine proteases D and E, had no effect. These four proteases were found to inhibit all pathways of complement due to the efficient degradation of several crucial components. Furthermore, S. aureus mutants lacking proteolytic enzymes were found to be more efficiently killed in human blood. Taken together, the major proteases of S. aureus appear to be important for pathogen-mediated evasion of the human complement system.

  19. Direct detection and differentiation of pathogenic Leptospira species using a multi-gene targeted real time PCR approach.

    PubMed

    Ferreira, Ana Sofia; Costa, Pedro; Rocha, Teresa; Amaro, Ana; Vieira, Maria Luísa; Ahmed, Ahmed; Thompson, Gertrude; Hartskeerl, Rudy A; Inácio, João

    2014-01-01

    Leptospirosis is a growing public and veterinary health concern caused by pathogenic species of Leptospira. Rapid and reliable laboratory tests for the direct detection of leptospiral infections in animals are in high demand not only to improve diagnosis but also for understanding the epidemiology of the disease. In this work we describe a novel and simple TaqMan-based multi-gene targeted real-time PCR approach able to detect and differentiate Leptospira interrogans, L. kirschneri, L. borgpeteresenii and L. noguchii, which constitute the veterinary most relevant pathogenic species of Leptospira. The method uses sets of species-specific probes, and respective flanking primers, designed from ompL1 and secY gene sequences. To monitor the presence of inhibitors, a duplex amplification assay targeting both the mammal β-actin and the leptospiral lipL32 genes was implemented. The analytical sensitivity of all primer and probe sets was estimated to be <10 genome equivalents (GE) in the reaction mixture. Application of the amplification reactions on genomic DNA from a variety of pathogenic and non-pathogenic Leptospira strains and other non-related bacteria revealed a 100% analytical specificity. Additionally, pathogenic leptospires were successfully detected in five out of 29 tissue samples from animals (Mus spp., Rattus spp., Dolichotis patagonum and Sus domesticus). Two samples were infected with L. borgpetersenii, two with L. interrogans and one with L. kirschneri. The possibility to detect and identify these pathogenic agents to the species level in domestic and wildlife animals reinforces the diagnostic information and will enhance our understanding of the epidemiology of leptopirosis. PMID:25398140

  20. Direct Detection and Differentiation of Pathogenic Leptospira Species Using a Multi-Gene Targeted Real Time PCR Approach

    PubMed Central

    Ferreira, Ana Sofia; Costa, Pedro; Rocha, Teresa; Amaro, Ana; Vieira, Maria Luísa; Ahmed, Ahmed; Thompson, Gertrude; Hartskeerl, Rudy A.; Inácio, João

    2014-01-01

    Leptospirosis is a growing public and veterinary health concern caused by pathogenic species of Leptospira. Rapid and reliable laboratory tests for the direct detection of leptospiral infections in animals are in high demand not only to improve diagnosis but also for understanding the epidemiology of the disease. In this work we describe a novel and simple TaqMan-based multi-gene targeted real-time PCR approach able to detect and differentiate Leptospira interrogans, L. kirschneri, L. borgpeteresenii and L. noguchii, which constitute the veterinary most relevant pathogenic species of Leptospira. The method uses sets of species-specific probes, and respective flanking primers, designed from ompL1 and secY gene sequences. To monitor the presence of inhibitors, a duplex amplification assay targeting both the mammal β-actin and the leptospiral lipL32 genes was implemented. The analytical sensitivity of all primer and probe sets was estimated to be <10 genome equivalents (GE) in the reaction mixture. Application of the amplification reactions on genomic DNA from a variety of pathogenic and non-pathogenic Leptospira strains and other non-related bacteria revealed a 100% analytical specificity. Additionally, pathogenic leptospires were successfully detected in five out of 29 tissue samples from animals (Mus spp., Rattus spp., Dolichotis patagonum and Sus domesticus). Two samples were infected with L. borgpetersenii, two with L. interrogans and one with L. kirschneri. The possibility to detect and identify these pathogenic agents to the species level in domestic and wildlife animals reinforces the diagnostic information and will enhance our understanding of the epidemiology of leptopirosis. PMID:25398140

  1. Molecular Diversity of Anthracnose Pathogen Populations Associated with UK Strawberry Production Suggests Multiple Introductions of Three Different Colletotrichum Species.

    PubMed

    Baroncelli, Riccardo; Zapparata, Antonio; Sarrocco, Sabrina; Sukno, Serenella A; Lane, Charles R; Thon, Michael R; Vannacci, Giovanni; Holub, Eric; Sreenivasaprasad, Surapareddy

    2015-01-01

    Fragaria × ananassa (common name: strawberry) is a globally cultivated hybrid species belonging to Rosaceae family. Colletotrichum acutatum sensu lato (s.l.) is considered to be the second most economically important pathogen worldwide affecting strawberries. A collection of 148 Colletotrichum spp. isolates including 67 C. acutatum s.l. isolates associated with the phytosanitary history of UK strawberry production were used to characterize multi-locus genetic variation of this pathogen in the UK, relative to additional reference isolates that represent a worldwide sampling of the diversity of the fungus. The evidence indicates that three different species C. nymphaeae, C. godetiae and C. fioriniae are associated with strawberry production in the UK, which correspond to previously designated genetic groups A2, A4 and A3, respectively. Among these species, 12 distinct haplotypes were identified suggesting multiple introductions into the country. A subset of isolates was also used to compare aggressiveness in causing disease on strawberry plants and fruits. Isolates belonging to C. nymphaeae, C. godetiae and C. fioriniae representative of the UK anthracnose pathogen populations showed variation in their aggressiveness. Among the three species, C. nymphaeae and C. fioriniae appeared to be more aggressive compared to C. godetiae. This study highlights the genetic and pathogenic heterogeneity of the C. acutatum s.l. populations introduced into the UK linked to strawberry production. PMID:26086351

  2. Molecular Diversity of Anthracnose Pathogen Populations Associated with UK Strawberry Production Suggests Multiple Introductions of Three Different Colletotrichum Species

    PubMed Central

    Baroncelli, Riccardo; Zapparata, Antonio; Sarrocco, Sabrina; Sukno, Serenella A.; Lane, Charles R.; Thon, Michael R.; Vannacci, Giovanni; Holub, Eric; Sreenivasaprasad, Surapareddy

    2015-01-01

    Fragaria × ananassa (common name: strawberry) is a globally cultivated hybrid species belonging to Rosaceae family. Colletotrichum acutatum sensu lato (s.l.) is considered to be the second most economically important pathogen worldwide affecting strawberries. A collection of 148 Colletotrichum spp. isolates including 67 C. acutatum s.l. isolates associated with the phytosanitary history of UK strawberry production were used to characterize multi-locus genetic variation of this pathogen in the UK, relative to additional reference isolates that represent a worldwide sampling of the diversity of the fungus. The evidence indicates that three different species C. nymphaeae, C. godetiae and C. fioriniae are associated with strawberry production in the UK, which correspond to previously designated genetic groups A2, A4 and A3, respectively. Among these species, 12 distinct haplotypes were identified suggesting multiple introductions into the country. A subset of isolates was also used to compare aggressiveness in causing disease on strawberry plants and fruits. Isolates belonging to C. nymphaeae, C. godetiae and C. fioriniae representative of the UK anthracnose pathogen populations showed variation in their aggressiveness. Among the three species, C. nymphaeae and C. fioriniae appeared to be more aggressive compared to C. godetiae. This study highlights the genetic and pathogenic heterogeneity of the C. acutatum s.l. populations introduced into the UK linked to strawberry production. PMID:26086351

  3. Molecular Diversity of Anthracnose Pathogen Populations Associated with UK Strawberry Production Suggests Multiple Introductions of Three Different Colletotrichum Species.

    PubMed

    Baroncelli, Riccardo; Zapparata, Antonio; Sarrocco, Sabrina; Sukno, Serenella A; Lane, Charles R; Thon, Michael R; Vannacci, Giovanni; Holub, Eric; Sreenivasaprasad, Surapareddy

    2015-01-01

    Fragaria × ananassa (common name: strawberry) is a globally cultivated hybrid species belonging to Rosaceae family. Colletotrichum acutatum sensu lato (s.l.) is considered to be the second most economically important pathogen worldwide affecting strawberries. A collection of 148 Colletotrichum spp. isolates including 67 C. acutatum s.l. isolates associated with the phytosanitary history of UK strawberry production were used to characterize multi-locus genetic variation of this pathogen in the UK, relative to additional reference isolates that represent a worldwide sampling of the diversity of the fungus. The evidence indicates that three different species C. nymphaeae, C. godetiae and C. fioriniae are associated with strawberry production in the UK, which correspond to previously designated genetic groups A2, A4 and A3, respectively. Among these species, 12 distinct haplotypes were identified suggesting multiple introductions into the country. A subset of isolates was also used to compare aggressiveness in causing disease on strawberry plants and fruits. Isolates belonging to C. nymphaeae, C. godetiae and C. fioriniae representative of the UK anthracnose pathogen populations showed variation in their aggressiveness. Among the three species, C. nymphaeae and C. fioriniae appeared to be more aggressive compared to C. godetiae. This study highlights the genetic and pathogenic heterogeneity of the C. acutatum s.l. populations introduced into the UK linked to strawberry production.

  4. An Enterotoxin-Bearing Pathogenicity Island in Staphylococcus epidermidis▿†

    PubMed Central

    Madhusoodanan, Jyoti; Seo, Keun Seok; Remortel, Brian; Park, Joo Youn; Hwang, Sun Young; Fox, Lawrence K.; Park, Yong Ho; Deobald, Claudia F.; Wang, Dan; Liu, Song; Daugherty, Sean C.; Gill, Ann Lindley; Bohach, Gregory A.; Gill, Steven R.

    2011-01-01

    Cocolonization of human mucosal surfaces causes frequent encounters between various staphylococcal species, creating opportunities for the horizontal acquisition of mobile genetic elements. The majority of Staphylococcus aureus toxins and virulence factors are encoded on S. aureus pathogenicity islands (SaPIs). Horizontal movement of SaPIs between S. aureus strains plays a role in the evolution of virulent clinical isolates. Although there have been reports of the production of toxic shock syndrome toxin 1 (TSST-1), enterotoxin, and other superantigens by coagulase-negative staphylococci, no associated pathogenicity islands have been found in the genome of Staphylococcus epidermidis, a generally less virulent relative of S. aureus. We show here the first evidence of a composite S. epidermidis pathogenicity island (SePI), the product of multiple insertions in the genome of a clinical isolate. The taxonomic placement of S. epidermidis strain FRI909 was confirmed by a number of biochemical tests and multilocus sequence typing. The genome sequence of this strain was analyzed for other unique gene clusters and their locations. This pathogenicity island encodes and expresses staphylococcal enterotoxin C3 (SEC3) and staphylococcal enterotoxin-like toxin L (SElL), as confirmed by quantitative reverse transcription-PCR (qRT-PCR) and immunoblotting. We present here an initial characterization of this novel pathogenicity island, and we establish that it is stable, expresses enterotoxins, and is not obviously transmissible by phage transduction. We also describe the genome sequence, excision, replication, and packaging of a novel bacteriophage in S. epidermidis FRI909, as well as attempts to mobilize the SePI element by this phage. PMID:21317317

  5. Impact of Environmental Cues on Staphylococcal Quorum Sensing and Biofilm Development.

    PubMed

    Kavanaugh, Jeffrey S; Horswill, Alexander R

    2016-06-10

    Staphylococci are commensal bacteria that colonize the epithelial surfaces of humans and many other mammals. These bacteria can also attach to implanted medical devices and develop surface-associated biofilm communities that resist clearance by host defenses and available chemotherapies. These communities are often associated with persistent staphylococcal infections that place a tremendous burden on the healthcare system. Understanding the regulatory program that controls staphylococcal biofilm development, as well as the environmental conditions that modulate this program, has been a focal point of research in recent years. A central regulator controlling biofilm development is a peptide quorum-sensing system, also called the accessory gene regulator or agr system. In the opportunistic pathogen Staphylococcus aureus, the agr system controls production of exo-toxins and exo-enzymes essential for causing infections, and simultaneously, it modulates the ability of this pathogen to attach to surfaces and develop a biofilm, or to disperse from the biofilm state. In this review, we explore advances on the interconnections between the agr quorum-sensing system and biofilm mechanisms, and topics covered include recent findings on how different environmental conditions influence quorum sensing, the impact on biofilm development, and ongoing questions and challenges in the field. As our understanding of the quorum sensing and biofilm interconnection advances, there are growing opportunities to take advantage of this knowledge and develop therapeutic approaches to control staphylococcal infections.

  6. River Networks As Ecological Corridors for Species, Populations and Pathogens of Water-Borne Disease

    NASA Astrophysics Data System (ADS)

    Rinaldo, A.

    2014-12-01

    River basins are a natural laboratory for the study of the integration of hydrological, ecological and geomorphological processes. Moving from morphological and functional analyses of dendritic geometries observed in Nature over a wide range of scales, this Lecture addresses essential ecological processes that take place along dendritic structures, hydrology-driven and controlled, like e.g.: population migrations and human settlements, that historically proceeded along river networks to follow water supply routes; riparian ecosystems composition that owing to their positioning along streams play crucial roles in their watersheds and in the loss of biodiversity proceeding at unprecedented rates; waterborne disease spreading, like epidemic cholera that exhibits epidemic patterns that mirror those of watercourses and of human mobility and resurgences upon heavy rainfall. Moreover, the regional incidence of Schistosomiasis, a parasitic waterborne disease, and water resources developments prove tightly related, and proliferative kidney disease in fish thrives differently in pristine and engineered watercourses: can we establish quantitatively the critical linkages with hydrologic drivers and controls? How does connectivity within a river network affect community composition or the spreading mechanisms? Does the river basin act as a template for biodiversity or for species' persistence? Are there hydrologic controls on epidemics of water-borne disease? Here, I shall focus on the noteworthy scientific perspectives provided by spatially explicit eco-hydrological studies centered on river networks viewed as ecological corridors for species, populations and pathogens of waterborne disease. A notable methodological coherence is granted by the mathematical description of river networks as the support for reactive transport. The Lecture overviews a number of topics idiosyncratically related to my own research work but ideally aimed at a coherent body of materials and methods. A

  7. Formic acid and acetic acid induce a programmed cell death in pathogenic Candida species.

    PubMed

    Lastauskienė, Eglė; Zinkevičienė, Auksė; Girkontaitė, Irutė; Kaunietis, Arnoldas; Kvedarienė, Violeta

    2014-09-01

    Cutaneous fungal infections are common and widespread. Antifungal agents used for the treatment of these infections often have undesirable side effects. Furthermore, increased resistance of the microorganisms to the antifungal drugs becomes the growing problem. Accordingly, the search for natural antifungal compounds continues to receive attention. Apoptosis is highly regulated programmed cell death. During yeast cell apoptosis, amino acids and peptides are released and can stimulate regeneration of human epithelium cells. Thus, detection of chemical compounds inducing apoptosis in yeast and nontoxic for humans is of great medical relevance. The aim of this study was to detect chemical compound inducing apoptosis in pathogenic Candida species with the lowest toxicity to the mammalian cells. Five chemical compounds--acetic acid, sodium bicarbonate, potassium carbonate, lithium acetate, and formic acid--were tested for evaluation of antifungal activity on C. albicans, C. guilliermondii, and C. lusitaniae. The results showed that acetic acid and formic acid at the lowest concentrations induced yeast cells death. Apoptosis analysis revealed that cells death was accompanied by activation of caspase. Minimal inhibitory concentrations of potassium carbonate and sodium bicarbonate induced Candida cells necrosis. Toxicity test with mammalian cell cultures showed that formic acid has the lowest effect on the growth of Jurkat and NIH 3T3 cells. In conclusion, our results show that a low concentration of formic acid induces apoptosis-like programmed cell death in the Candida yeast and has a minimal effect on the survivability of mammalian cells, suggesting potential applications in the treatment of these infections. PMID:24752490

  8. Analyses of methyltransferases across the pathogenicity spectrum of different mycobacterial species point to an extremophile connection.

    PubMed

    Grover, Sonam; Gupta, Paras; Kahlon, Parvinderdeep S; Goyal, Sukriti; Grover, Abhinav; Dalal, Kuldeep; Sabeeha; Ehtesham, Nasreen Z; Hasnain, Seyed E

    2016-05-26

    Tuberculosis is a devastating disease, taking one human life every 20 seconds globally. We hypothesize that professional pathogens such as M.tb have acquired specific features that might assist in causing infection, persistence and transmissible pathology in their host. We have identified 121 methyltransferases (MTases) in the M.tb proteome, which use a variety of substrates - DNA, RNA, protein, intermediates of mycolic acid biosynthesis and other fatty acids - that are involved in cellular maintenance within the host. A comparative analysis of the proteome of the virulent strain H37Rv and the avirulent strain H37Ra identified 3 MTases, which displayed significant variations in terms of N-terminal extension/deletion and point mutations, possibly impacting various physicochemical properties. The cross-proteomic comparison of MTases of M.tb H37Rv with 15 different Mycobacterium species revealed the acquisition of novel MTases in a MTB complex as a function of evolution. Phylogenetic analysis revealed that these newly acquired MTases showed common roots with certain extremophiles such as halophilic and acidophilic organisms. Our results establish an evolutionary relationship of M.tb with halotolerant organisms and also the role of MTases of M.tb in withstanding the host osmotic stress, thereby pointing to their likely role in pathogenesis, virulence and niche adaptation. PMID:26983646

  9. Pathogenic Leptospira Species Acquire Factor H and Vitronectin via the Surface Protein LcpA

    PubMed Central

    da Silva, Ludmila Bezerra; Miragaia, Lidia dos Santos; Breda, Leandro Carvalho Dantas; Abe, Cecilia Mari; Schmidt, Mariana Costa Braga; Moro, Ana Maria; Monaris, Denize; Conde, Jonas Nascimento; Józsi, Mihály; Isaac, Lourdes; Abreu, Patrícia Antônia Estima

    2014-01-01

    Upon infection, pathogenic Leptospira species bind several complement regulators in order to overcome host innate immunity. We previously characterized a 20-kDa leptospiral surface protein which interacts with C4b binding protein (C4BP): leptospiral complement regulator-acquiring protein A (LcpA). Here we show that LcpA also interacts with human factor H (FH), which remains functionally active once bound to the protein. Antibodies directed against short consensus repeat 20 (SCR20) inhibited binding of FH to LcpA by approximately 90%, thus confirming that this particular domain is involved in the interaction. We have also shown for the first time that leptospires bind human vitronectin and that the interaction is mediated by LcpA. Coincubation with heparin blocked LcpA-vitronectin interaction in a dose-dependent manner, strongly suggesting that binding may occur through the heparin binding domains of vitronectin. LcpA also bound to the terminal pathway component C9 and inhibited Zn2+-induced polymerization and membrane attack complex (MAC) formation. Competitive binding assays indicated that LcpA interacts with C4BP, FH, and vitronectin through distinct sites. Taken together, our findings indicate that LcpA may play a role in leptospiral immune evasion. PMID:25534939

  10. Ferrets as sentinels of the presence of pathogenic Cryptococcus species in the Mediterranean environment.

    PubMed

    Morera, Neus; Hagen, Ferry; Juan-Sallés, Carles; Artigas, Carlos; Patricio, Rui; Serra, Juan Ignacio; Colom, Ma Francisca

    2014-08-01

    Cryptococcus gattii is a pathogenic environmental yeast that is considered to be emerging in different areas of the world including the Mediterranean Basin. Exposure to infection might be more likely in animals than in human beings, given their closer relationship with the natural habitat of the yeast, vegetation and soil. Thus, animals, and especially pets, can act as indicators of the presence of this yeast in a determined area. Domestic ferrets (Mustela putorius furo) have become common pets in the past 10-20 years. Their natural behavior of sniffing around and going inside narrow spaces makes them prone to contact with decaying organic matter and soil, the substrate for Cryptococcus species. This study describes two cases of cryptococcosis in ferrets in the Iberian Peninsula and Balearic Islands and documents a relationship of ferret cryptococcosis with environmental isolates in the same locations. Here, we emphasize the importance of how an adequate identification and environmental search of the yeast leads to a better understanding of the epidemiology of cryptococcosis and suggests ferrets may act as sentinels for this fungal disease. PMID:24962111

  11. Hiding in Plain Sight: Interplay between Staphylococcal Biofilms and Host Immunity

    PubMed Central

    Scherr, Tyler D.; Heim, Cortney E.; Morrison, John M.; Kielian, Tammy

    2014-01-01

    Staphylococcus aureus and Staphylococcus epidermidis are notable for their propensity to form biofilms on implanted medical devices. Staphylococcal biofilm infections are typified by their recalcitrance to antibiotics and ability to circumvent host immune-mediated clearance, resulting in the establishment of chronic infections that are often recurrent in nature. Indeed, the immunomodulatory lifestyle of biofilms seemingly shapes the host immune response to ensure biofilm engraftment and persistence in an immune competent host. Here, we provide a brief review of the mechanisms whereby S. aureus and S. epidermidis biofilms manipulate host–pathogen interactions and discuss the concept of microenvironment maintenance in infectious outcomes, as well as speculate how these findings pertain to the challenges of staphylococcal vaccine development. PMID:24550921

  12. Genome Content and Phylogenomics Reveal both Ancestral and Lateral Evolutionary Pathways in Plant-Pathogenic Streptomyces Species

    PubMed Central

    Huguet-Tapia, Jose C.; Lefebure, Tristan; Badger, Jonathan H.; Guan, Dongli; Stanhope, Michael J.

    2016-01-01

    Streptomyces spp. are highly differentiated actinomycetes with large, linear chromosomes that encode an arsenal of biologically active molecules and catabolic enzymes. Members of this genus are well equipped for life in nutrient-limited environments and are common soil saprophytes. Out of the hundreds of species in the genus Streptomyces, a small group has evolved the ability to infect plants. The recent availability of Streptomyces genome sequences, including four genomes of pathogenic species, provided an opportunity to characterize the gene content specific to these pathogens and to study phylogenetic relationships among them. Genome sequencing, comparative genomics, and phylogenetic analysis enabled us to discriminate pathogenic from saprophytic Streptomyces strains; moreover, we calculated that the pathogen-specific genome contains 4,662 orthologs. Phylogenetic reconstruction suggested that Streptomyces scabies and S. ipomoeae share an ancestor but that their biosynthetic clusters encoding the required virulence factor thaxtomin have diverged. In contrast, S. turgidiscabies and S. acidiscabies, two relatively unrelated pathogens, possess highly similar thaxtomin biosynthesis clusters, which suggests that the acquisition of these genes was through lateral gene transfer. PMID:26826232

  13. Genome Content and Phylogenomics Reveal both Ancestral and Lateral Evolutionary Pathways in Plant-Pathogenic Streptomyces Species.

    PubMed

    Huguet-Tapia, Jose C; Lefebure, Tristan; Badger, Jonathan H; Guan, Dongli; Pettis, Gregg S; Stanhope, Michael J; Loria, Rosemary

    2016-04-01

    Streptomyces spp. are highly differentiated actinomycetes with large, linear chromosomes that encode an arsenal of biologically active molecules and catabolic enzymes. Members of this genus are well equipped for life in nutrient-limited environments and are common soil saprophytes. Out of the hundreds of species in the genus Streptomyces, a small group has evolved the ability to infect plants. The recent availability of Streptomyces genome sequences, including four genomes of pathogenic species, provided an opportunity to characterize the gene content specific to these pathogens and to study phylogenetic relationships among them. Genome sequencing, comparative genomics, and phylogenetic analysis enabled us to discriminate pathogenic from saprophytic Streptomyces strains; moreover, we calculated that the pathogen-specific genome contains 4,662 orthologs. Phylogenetic reconstruction suggested that Streptomyces scabies and S. ipomoeae share an ancestor but that their biosynthetic clusters encoding the required virulence factor thaxtomin have diverged. In contrast, S. turgidiscabies and S. acidiscabies, two relatively unrelated pathogens, possess highly similar thaxtomin biosynthesis clusters, which suggests that the acquisition of these genes was through lateral gene transfer. PMID:26826232

  14. Isolation and Characterization of Plant-Pathogenic Streptomyces Species Associated with Common Scab-Infected Potato Tubers in Newfoundland.

    PubMed

    Fyans, Joanna K; Bown, Luke; Bignell, Dawn R D

    2016-02-01

    Potato common scab (CS) is an economically important crop disease that is caused by several members of the genus Streptomyces. In this study, we characterized the plant-pathogenic Streptomyces spp. associated with CS-infected potato tubers harvested in Newfoundland, Canada. A total of 17 pathogenic Streptomyces isolates were recovered from potato scab lesions, of which eight were determined to be most similar to the known CS pathogen S. europaeiscabiei. All eight S. europaeiscabiei isolates were found to produce the thaxtomin A phytotoxin and to harbor the nec1 virulence gene, and most also carry the putative virulence gene tomA. The remaining isolates appear to be novel pathogenic species that do not produce thaxtomin A, and only two of these isolates were determined to harbor the nec1 or tomA genes. Of the non-thaxtomin-producing isolates, strain 11-1-2 was shown to exhibit a severe pathogenic phenotype against different plant hosts and to produce a novel, secreted phytotoxic substance. This is the first report documenting the plant-pathogenic Streptomyces spp. associated with CS disease in Newfoundland. Furthermore, our findings provide further evidence that phytotoxins other than thaxtomin A may also contribute to the development of CS by Streptomyces spp.

  15. Isolation and Characterization of Plant-Pathogenic Streptomyces Species Associated with Common Scab-Infected Potato Tubers in Newfoundland.

    PubMed

    Fyans, Joanna K; Bown, Luke; Bignell, Dawn R D

    2016-02-01

    Potato common scab (CS) is an economically important crop disease that is caused by several members of the genus Streptomyces. In this study, we characterized the plant-pathogenic Streptomyces spp. associated with CS-infected potato tubers harvested in Newfoundland, Canada. A total of 17 pathogenic Streptomyces isolates were recovered from potato scab lesions, of which eight were determined to be most similar to the known CS pathogen S. europaeiscabiei. All eight S. europaeiscabiei isolates were found to produce the thaxtomin A phytotoxin and to harbor the nec1 virulence gene, and most also carry the putative virulence gene tomA. The remaining isolates appear to be novel pathogenic species that do not produce thaxtomin A, and only two of these isolates were determined to harbor the nec1 or tomA genes. Of the non-thaxtomin-producing isolates, strain 11-1-2 was shown to exhibit a severe pathogenic phenotype against different plant hosts and to produce a novel, secreted phytotoxic substance. This is the first report documenting the plant-pathogenic Streptomyces spp. associated with CS disease in Newfoundland. Furthermore, our findings provide further evidence that phytotoxins other than thaxtomin A may also contribute to the development of CS by Streptomyces spp. PMID:26524546

  16. A Multiplex Assay for Detection of Staphylococcal and Streptococcal Exotoxins

    PubMed Central

    Sharma, Preeti; Wang, Ningyan; Chervin, Adam S.; Quinn, Cheryl L.; Stone, Jennifer D.; Kranz, David M.

    2015-01-01

    Staphylococcal and streptococcal exotoxins, also known as superantigens, mediate a range of diseases including toxic shock syndrome, and they exacerbate skin, pulmonary and systemic infections caused by these organisms. When present in food sources they can cause enteric effects commonly known as food poisoning. A rapid, sensitive assay for the toxins would enable testing of clinical samples and improve surveillance of food sources. Here we developed a bead-based, two-color flow cytometry assay using single protein domains of the beta chain of T cell receptors engineered for high-affinity for staphylococcal (SEA, SEB and TSST-1) and streptococcal (SpeA and SpeC) toxins. Site-directed biotinylated forms of these high-affinity agents were used together with commercial, polyclonal, anti-toxin reagents to enable specific and sensitive detection with SD50 values of 400 pg/ml (SEA), 3 pg/ml (SEB), 25 pg/ml (TSST-1), 6 ng/ml (SpeA), and 100 pg/ml (SpeC). These sensitivities were in the range of 4- to 80-fold higher than achieved with standard ELISAs using the same reagents. A multiplex format of the assay showed reduced sensitivity due to higher noise associated with the use of multiple polyclonal agents, but the sensitivities were still well within the range necessary for detection in food sources or for rapid detection of toxins in culture supernatants. For example, the assay specifically detected toxins in supernatants derived from cultures of Staphylococcus aureus. Thus, these reagents can be used for simultaneous detection of the toxins in food sources or culture supernatants of potential pathogenic strains of Staphylococcus aureus and Streptococcus pyogenes. PMID:26305471

  17. Fusarium foetens, a new species pathogenic to begonia elatior hybrids (Begonia x hiemalis) and the sister taxon of the Fusarium oxysporum species complex.

    PubMed

    Schroers, H-J; Baayen, R P; Meffert, J P; de Gruyter, J; Hooftman, M; O'Donnell, K

    2004-01-01

    A new disease recently was discovered in begonia elatior hybrid (Begonia × hiemalis) nurseries in The Netherlands. Diseased plants showed a combination of basal rot, vein yellowing and wilting and the base of collapsing plants was covered by unusually large masses of Fusarium macroconidia. A species of Fusarium was isolated consistently from the discolored veins of leaves and stems. It differed morphologically from F. begoniae, a known agent of begonia flower, leaf and stem blight. The Fusarium species resembled members of the F. oxysporum species complex in producing short monophialides on the aerial mycelium and abundant chlamydospores. Other phenotypic characters such as polyphialides formed occasionally in at least some strains, relatively long monophialides intermingled with the short monophialides formed on the aerial mycelium, distinct sporodochial conidiomata, and distinct pungent colony odor distinguished it from the F. oxysporum species complex. Phylogenetic analyses of partial sequences of the mitochondrial small subunit of the ribosomal DNA (mtSSU rDNA), nuclear translation elongation factor 1α (EF-1α) and β-tubulin gene exons and introns indicate that the Fusarium species represents a sister group of the F. oxysporum species complex. Begonia × hiemalis cultivars Bazan, Bellona and Netja Dark proved to be highly susceptible to the new species. Inoculated plants developed tracheomycosis within 4 wk, and most died within 8 wk. The new taxon was not pathogenic to Euphorbia pulcherrima, Impatiens walleriana and Saintpaulia ionantha that commonly are grown in nurseries along with B. × hiemalis. Inoculated plants of Cyclamen persicum did not develop the disease but had discolored vessels from which the inoculated fungus was isolated. Given that the newly discovered begonia pathogen is distinct in pathogenicity, morphology and phylogeny from other fusaria, it is described here as a new species, Fusarium foetens. PMID:21148861

  18. Antimicrobials for staphylococcal pathogens that are refractory to resistance development

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacteriophages are viruses exclusively infecting bacteria and therefore offer suitable tools for their detection and control. At the end of their multiplication cycle, most phages lyse their hosts from within by means of an endolysin (peptidoglycan hydrolase), thereby enabling release of the phage p...

  19. [In vitro tests of the antagonistic behavior of Trichoderma spp. against pathogenic species of the horticultural region of La Plata, Argentina].

    PubMed

    Mónaco, C; Perelló, A; Rollán, M C

    1994-12-01

    The antagonistic properties of seven Trichoderma species in front of the pathogens Fusarium oxysporum, F. equiseti, F. solani, Sclerotinia sclerotiorum, S. minor, Rhizoctonia sp. and Sclerotium rolfsii was evaluated in vitro. Those microorganisms were isolated from horticultural soils of La Plata in order to test the antagonistic-pathogenic relationship. Dual cultures on PDA 2% were used. All the species of Trichoderma grew in the culture medium with a colonization value higher than 50%. Differences in the antagonistic behaviour of the pathogens were observed depending on the species with which they interacted. The presence of diffusible metabolites to the medium was demonstrated in almost 80% of the pathogens antagonists tested. PMID:7772296

  20. Distribution and Diversity of Pathogenic Leptospira Species in Peri-domestic Surface Waters from South Central Chile

    PubMed Central

    Mason, Meghan R.; Encina, Carolina; Sreevatsan, Srinand; Muñoz-Zanzi, Claudia

    2016-01-01

    Background Leptospirosis is a neglected zoonosis affecting animals and humans caused by infection with Leptospira. The bacteria can survive outside of hosts for long periods of time in soil and water. While identification of Leptospira species from human cases and animal reservoirs are increasingly reported, little is known about the diversity of pathogenic Leptospira species in the environment and how surveillance of the environment might be used for monitoring and controlling disease. Methods and Findings Water samples (n = 104) were collected from the peri-domestic environment of 422 households from farms, rural villages, and urban slums participating in a broader study on the eco-epidemiology of leptospirosis in the Los Rios Region, Chile, between October 2010 and April 2012. The secY region of samples, previously detected as pathogenic Leptospira by PCR, was amplified and sequenced. Sequences were aligned using ClustalW in MEGA, and a minimum spanning tree was created in PHYLOViZ using the goeBURST algorithm to assess sequence similarity. Sequences from four clinical isolates, 17 rodents, and 20 reference strains were also included in the analysis. Overall, water samples contained L. interrogans, L. kirschneri, and L. weilii, with descending frequency. All species were found in each community type. The distribution of the species differed by the season in which the water samples were obtained. There was no evidence that community-level prevalence of Leptospira in dogs, rodents, or livestock influenced pathogen diversity in the water samples. Conclusions This study reports the presence of pathogenic Leptospira in the peri-domestic environment of households in three community types and the differences in Leptospira diversity at the community level. Systematic environmental surveillance of Leptospira can be used for detecting changes in pathogen diversity and to identify and monitor contaminated areas where an increased risk of human infection exists. PMID

  1. Decortication of the heart for staphylococcal pericarditis

    PubMed Central

    Perera, N. V.

    1971-01-01

    A case of acute staphylococcal pericarditis with constriction of the heart is reported. The response to antibiotics and simple pericardial drainage was poor. Pericardiectomy and decortication of the heart was performed on a moribund patient. Marked improvement followed surgery combined with intensive antibiotic therapy. At follow-up eight months later, the patient was a normal active 6-year-old boy. Images PMID:5101264

  2. Susceptibility of avian species to North American H13 low pathogenic avian influenza viruses.

    PubMed

    Brown, Justin; Poulson, Rebecca; Carter, Deborah; Lebarbenchon, Camille; Pantin-Jackwood, Mary; Spackman, Erica; Shepherd, Eric; Killian, Mary; Stallknecht, David

    2012-12-01

    Gulls are widely recognized reservoirs for low pathogenic avian influenza (LPAI) viruses; however, the subtypes maintained in these populations and/or the transmission mechanisms involved are poorly understood. Although, a wide diversity of influenza viruses have been isolated from gulls, two hemagglutinin subtypes (H13 and H16) are rarely detected in other avian groups, and existing surveillance data suggests they are maintained almost exclusively within gull populations. In order to evaluate the host range of these gull-adapted influenza subtypes and to characterize viral infection in the gull host, we conducted a series of challenge experiments, with multiple North American strains of H13 LPAI virus in ring-billed gulls (Larus delawarensis), mallards (Anas platyrhynchos), chickens (Gallus domesticus), and turkeys (Meleagris gallopavo). The susceptibility to H13 LPAI viruses varied between species and viral strain. Gulls were highly susceptible to H13 LPAI virus infection and excreted virus via the oropharynx and cloaca for several days. The quantity and duration of shedding was similar between the two routes. Turkeys and ducks were resistant to infection with most strains of H13 LPAI virus, but low numbers of inoculated birds were infected after challenge with specific viral strains. Chickens were refractory to infection with all strains of H13 LPAI virus they were challenged with. The experimental results presented herein are consistent with existing surveillance data on H13 LPAI viruses in birds, and indicate that influenza viruses of the H13 subtype are strongly host-adapted to gulls, but rare spill-over into aberrant hosts (i.e., turkeys and ducks) can occur.

  3. Species- and Strain-Specific Adaptation of the HSP70 Super Family in Pathogenic Trypanosomatids

    PubMed Central

    Drini, Sima; Criscuolo, Alexis; Lechat, Pierre; Imamura, Hideo; Skalický, Tomáš; Rachidi, Najma; Lukeš, Julius; Dujardin, Jean-Claude; Späth, Gerald F.

    2016-01-01

    All eukaryotic genomes encode multiple members of the heat shock protein 70 (HSP70) family, which evolved distinctive structural and functional features in response to specific environmental constraints. Phylogenetic analysis of this protein family thus can inform on genetic and molecular mechanisms that drive species-specific environmental adaptation. Here we use the eukaryotic pathogen Leishmania spp. as a model system to investigate the evolution of the HSP70 protein family in an early-branching eukaryote that is prone to gene amplification and adapts to cytotoxic host environments by stress-induced and chaperone-dependent stage differentiation. Combining phylogenetic and comparative analyses of trypanosomatid genomes, draft genome of Paratrypanosoma and recently published genome sequences of 204 L. donovani field isolates, we gained unique insight into the evolutionary dynamics of the Leishmania HSP70 protein family. We provide evidence for (i) significant evolutionary expansion of this protein family in Leishmania through gene amplification and functional specialization of highly conserved canonical HSP70 members, (ii) evolution of trypanosomatid-specific, non-canonical family members that likely gained ATPase-independent functions, and (iii) loss of one atypical HSP70 member in the Trypanosoma genus. Finally, we reveal considerable copy number variation of canonical cytoplasmic HSP70 in highly related L. donovani field isolates, thus identifying this locus as a potential hot spot of environment–genotype interaction. Our data draw a complex picture of the genetic history of HSP70 in trypanosomatids that is driven by the remarkable plasticity of the Leishmania genome to undergo massive intra-chromosomal gene amplification to compensate for the absence of regulated transcriptional control in these parasites. PMID:27371955

  4. Species- and Strain-Specific Adaptation of the HSP70 Super Family in Pathogenic Trypanosomatids.

    PubMed

    Drini, Sima; Criscuolo, Alexis; Lechat, Pierre; Imamura, Hideo; Skalický, Tomáš; Rachidi, Najma; Lukeš, Julius; Dujardin, Jean-Claude; Späth, Gerald F

    2016-01-01

    All eukaryotic genomes encode multiple members of the heat shock protein 70 (HSP70) family, which evolved distinctive structural and functional features in response to specific environmental constraints. Phylogenetic analysis of this protein family thus can inform on genetic and molecular mechanisms that drive species-specific environmental adaptation. Here we use the eukaryotic pathogen Leishmania spp. as a model system to investigate the evolution of the HSP70 protein family in an early-branching eukaryote that is prone to gene amplification and adapts to cytotoxic host environments by stress-induced and chaperone-dependent stage differentiation. Combining phylogenetic and comparative analyses of trypanosomatid genomes, draft genome of Paratrypanosoma and recently published genome sequences of 204 L. donovani field isolates, we gained unique insight into the evolutionary dynamics of the Leishmania HSP70 protein family. We provide evidence for (i) significant evolutionary expansion of this protein family in Leishmania through gene amplification and functional specialization of highly conserved canonical HSP70 members, (ii) evolution of trypanosomatid-specific, non-canonical family members that likely gained ATPase-independent functions, and (iii) loss of one atypical HSP70 member in the Trypanosoma genus. Finally, we reveal considerable copy number variation of canonical cytoplasmic HSP70 in highly related L. donovani field isolates, thus identifying this locus as a potential hot spot of environment-genotype interaction. Our data draw a complex picture of the genetic history of HSP70 in trypanosomatids that is driven by the remarkable plasticity of the Leishmania genome to undergo massive intra-chromosomal gene amplification to compensate for the absence of regulated transcriptional control in these parasites. PMID:27371955

  5. Botryosphaeriaceae as potential pathogens of prunus species in South Africa, with descriptions of Diplodia africana and Lasiodiplodia plurivora sp. nov.

    PubMed

    Damm, Ulrike; Crous, Pedro W; Fourie, Paul H

    2007-01-01

    Botryosphaeriaceae are common dieback and canker pathogens of woody host plants, including stone fruit trees. In the present study the diversity of members of the Botryosphaeriaceae isolated from symptomatic wood of Prunus species (plum, peach, nectarine and apricot) was determined in stone fruit-growing areas in South Africa. Morphological and cultural characteristics as well as DNA sequence data (5.8S rDNA, ITS-1, ITS-2 and EF-1a) were used to identify known members and describe novel members of Botryosphaeriaceae. From the total number of wood samples collected (258) 67 isolates of Botryosphaeriaceae were obtained, from which eight species were identified. All species were associated with wood necrosis. Diplodia seriata (= "Botryosphaeria" obtusa) was dominant, and present on all four Prunus species sampled, followed by Neofusicoccum vitifusiforme and N. australe. First reports from Prunus spp. include N. vitifusiforme, Dothiorella viticola and Diplodia pinea. This is also the first report of D. mutila from South Africa. Two species are newly described, namely Lasiodiplodia plurivora sp. nov. from P. salicina and Diplodia africana sp. nov. from P. persica. All species, except Dothiorella viticola, caused lesions on green nectarine and/or plum shoots in a detached shoot pathogenicity assay.

  6. 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...

  7. Clinical, Pathological, and Prognostic Characteristics of Glomerulonephritis Related to Staphylococcal Infection

    PubMed Central

    Wang, Si-Yang; Bu, Ru; Zhang, Qi; Liang, Shuang; Wu, Jie; Liu, Xue-Guang Zhang Shu-Wen; Cai, Guang-Yan; Chen, Xiang-Mei

    2016-01-01

    Abstract Staphylococcal infection has become a common cause of postinfectious glomerulonephritis in the past 3 decades. Because few investigations focus on this disease, the demographics and clinicopathological features of glomerulonephritis related to staphylococcal infection are not well characterized. We conducted a pooled analysis of published literature in electronic databases and analyzed the clinical features, laboratory findings, and histopathological changes. The patients were divided into 4 groups based on their prognosis: remission, persistent renal dysfunction, end-stage renal disease (ESRD), or death. A logistic regression model was used to identify the determinants of disease outcome. A total of 83 (64 men) patients with glomerulonephritis related to staphylococcal infection from 31 reports were analyzed. The mean age was 58 years (58 ± 17). Majority of the reports originated from Taiwan, Japan, and the United States. Clinical characteristics of the cases were hematuria (82/83), proteinuria (78/83), and acute kidney injury (75/83). Visceral abscesses (26/83) and skin infections (24/83) were the common sites of infection. Methicillin-resistant Staphylococcus aureus was the most common pathogen. The dominant or codominant deposition of IgA or C3 along the glomeruli was an important feature identified by immunofluorescence. There were 19 patients (22.9%) that progressed to dialysis-dependent ESRD. Twelve patients (14.5%) died. A univariate regression analysis indicated that diabetes mellitus (DM) (odds ratio [OR] 2.96; 95% confidence interval [CI] 1.03–8.48; P = 0.04) and age (OR 4.80; 95% CI 1.84–12.53; P = 0.001) were risk factors for ESRD or death. A multivariate regression analysis also revealed that age (OR 4.90; 95% CI 1.82–13.18; P = 0.002) and DM (OR 3.07; 95% CI 0.98–9.59; P = 0.05) were independent risk factors for unfavorable prognosis. Glomerulonephritis related to staphylococcal infection has different features

  8. Fusion of two divergent fungal individuals led to the recent emergence of a unique widespread pathogen species

    PubMed Central

    Stukenbrock, Eva Holtgrewe; Christiansen, Freddy Bugge; Hansen, Troels Toftebjerg; Dutheil, Julien Yann; Schierup, Mikkel Heide

    2012-01-01

    In a genome alignment of five individuals of the ascomycete fungus Zymoseptoria pseudotritici, a close relative of the wheat pathogen Z. tritici (synonym Mycosphaerella graminicola), we observed peculiar diversity patterns. Long regions up to 100 kb without variation alternate with similarly long regions of high variability. The variable segments in the genome alignment are organized into two main haplotype groups that have diverged ∼3% from each other. The genome patterns in Z. pseudotritici are consistent with a hybrid speciation event resulting from a cross between two divergent haploid individuals. The resulting hybrids formed the new species without backcrossing to the parents. We observe no variation in 54% of the genome in the five individuals and estimate a complete loss of variation for at least 30% of the genome in the entire species. A strong population bottleneck following the hybridization event caused this loss of variation. Variable segments in the Z. pseudotritici genome exhibit the two haplotypes contributed by the parental individuals. From our previously estimated recombination map of Z. tritici and the size distribution of variable chromosome blocks untouched by recombination we estimate that the hybridization occurred ∼380 sexual generations ago. We show that the amount of lost variation is explained by genetic drift during the bottleneck and by natural selection, as evidenced by the correlation of presence/absence of variation with gene density and recombination rate. The successful spread of this unique reproductively isolated pathogen highlights the strong potential of hybridization in the emergence of pathogen species with sexual reproduction. PMID:22711811

  9. Increased sensitivity to staphylococcal beta hemolysins of erythrocytes from chickens during aflatoxicosis.

    PubMed

    Doerr, J A; Huff, W E; Hamilton, P B

    1987-12-01

    The size of the zones of beta-hemolysis surrounding staphylococcal colonies on blood agar was found to be related to the level of dietary aflatoxin consumed by the chickens donating the blood. Zone sizes on blood from chickens fed the highest level of aflatoxin (10 micrograms/g of diet) were about six-fold larger than those on blood from control birds. The percentage of staphylococcal isolates displaying beta-hemolysis was increased from about 15% in normal blood to about 90% in blood from chickens fed aflatoxin (10 micrograms/g) whereas the time required for detection of beta-hemolysis was decreased by about one-half. The hemolytic activity of purified staphylococcal beta-hemolysin against suspensions of washed erythrocytes increased as the level of aflatoxin consumed by the donor chickens increased. These data imply a new mechanism for enhanced susceptibility of animals to infectious agents during mycotoxicoses whereby the animal is made more sensitive to the virulence factors of pathogens.

  10. Sequential analysis of staphylococcal colonization of body surfaces of patients undergoing vascular surgery.

    PubMed Central

    Levy, M F; Schmitt, D D; Edmiston, C E; Bandyk, D F; Krepel, C J; Seabrook, G R; Towne, J B

    1990-01-01

    Slime-producing coagulase-negative staphylococci are pathogens in vascular surgery by virtue of their ability to adhere to and persist on prosthetic graft material. Inguinal and abdominal skin sites were cultured in 41 patients upon hospitalization, and slime production and antimicrobial susceptibility were assessed in all recovered staphylococcal isolates. Twenty-one patients eventually underwent lower-extremity revascularization. In the operative population, cultures were also obtained on the day of surgery and fifth postoperative day. All 21 patients received perioperative cefazolin. Of 327 coagulase-negative staphylococci recovered, Staphylococcus epidermidis (47%), S. haemolyticus (21%), and S. hominis (10%) were the predominant isolates. Slime-producing coagulase-negative staphylococci were recovered from 17 of 21 patients at admission but only from 8 of 21 patients on day 5 postoperation (P less than 0.05). S. epidermidis isolates demonstrated increasing multiple resistance from admission to 5 days postoperation to methicillin, gentamicin, clindamycin, erythromycin, and trimethoprim-sulfamethoxazole (P less than 0.05). All coagulase-negative staphylococcal isolates were susceptible to ciprofloxacin and vancomycin. Slime-producing capability was not associated with increased methicillin resistance for the recovered isolates. The data demonstrate that patients enter the hospital colonized with slime-producing strains of coagulase-negative staphylococci and that during hospitalization the staphylococcal skin burden shifts from a predominately susceptible to a resistant microbial population, which may enhance the importance of slime production as a risk factor in lower-extremity revascularization. Images PMID:2332464

  11. A Reservoir Species for the Emerging Amphibian Pathogen Batrachochytrium dendrobatidis Thrives in a Landscape Decimated by Disease

    PubMed Central

    Reeder, Natalie M. M.; Pessier, Allan P.; Vredenburg, Vance T.

    2012-01-01

    Chytridiomycosis, a disease caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), is driving amphibian declines and extinctions in protected areas globally. The introduction of invasive reservoir species has been implicated in the spread of Bd but does not explain the appearance of the pathogen in remote protected areas. In the high elevation (>1500 m) Sierra Nevada of California, the native Pacific chorus frog, Pseudacris regilla, appears unaffected by chytridiomycosis while sympatric species experience catastrophic declines. We investigated whether P. regilla is a reservoir of Bd by comparing habitat occupancy before and after a major Bd outbreak and measuring infection in P. regilla in the field, monitoring susceptibility of P. regilla to Bd in the laboratory, examining tissues with histology to determine patterns of infection, and using an innovative soak technique to determine individual output of Bd zoospores in water. Pseudacris regilla persists at 100% of sites where a sympatric species has been extirpated from 72% in synchrony with a wave of Bd. In the laboratory, P. regilla carried loads of Bd as much as an order of magnitude higher than loads found lethal to sympatric species. Histology shows heavy Bd infection in patchy areas next to normal skin, a possible mechanism for tolerance. The soak technique was 77.8% effective at detecting Bd in water and showed an average output of 68 zoospores per minute per individual. The results of this study suggest P. regilla should act as a Bd reservoir and provide evidence of a tolerance mechanism in a reservoir species. PMID:22428071

  12. The Occurrence of Two Species of Entomophthorales (Entomophthoromycota), Pathogens of Sitobion avenae and Myzus persicae (Hemiptera: Aphididae), in Tunisia

    PubMed Central

    Boukhris-Bouhachem, Sonia; Eilenberg, Jørgen; Allagui, Mohamed Bechir; Jensen, Annette Bruun

    2013-01-01

    The natural occurrence of entomophthoralean fungi pathogenic towards aphids on cereal and potato crops was investigated in the years 2009, 2010, and 2011. Infected aphids were sampled in three bioclimatic zones in Tunisia (Beja, Cap bon, and Kairouan) and fungal species were determined based on morphological characters such as shape, size, and number of nuclei in the primary conidia. Polymerase Chain Reaction (PCR) on the internal transcribed spacer 1 region (ITS1) was used to verify morphological determination. Both methods gave consistent results and we documented for the first time the natural occurrence of two fungal species from the order Entomophthorales (phylum Entomophthoromycota), Pandora neoaphidis and Entomophthora planchoniana. Both fungi were recorded on the aphid species Sitobion avenae and Myzus persicae on barley ears and potato leaves, respectively. Moreover, natural mixed infections by both species (P. neoaphidis and E. planchoniana) were documented on the target aphids. This investigation provides basic information of entomopathogenic fungi infecting economically important aphids in Tunisia. PMID:23862158

  13. Detection and Identification of Bartonella Species Pathogenic for Humans by PCR Amplification Targeting the Riboflavin Synthase Gene (ribC)

    PubMed Central

    Johnson, G.; Ayers, M.; McClure, S. C. C.; Richardson, S. E.; Tellier, R.

    2003-01-01

    Several Bartonella species have now been implicated as human pathogens. The recovery of these fastidious organisms in the clinical microbiology laboratory remains difficult, and current methods are still relatively insensitive. Thus, the bartonellae are good candidates for detection by PCR. We have developed a PCR assay which uses a single primer pair targeting the riboflavin synthase gene (ribC) and detected six Bartonella species that have been implicated in human disease, B. henselae, B. quintana, B. bacilliformis, B. clarridgeiae, B. elizabethae, and B. vinsonii subsp. berkhoffii. Species identification is achieved simply by restriction enzyme digestion of the amplicon. This PCR assay appears to be specific for the Bartonella genus because it failed to amplify DNA from several other bacterial species. PMID:12624031

  14. Coagulase-negative staphylococci as reservoirs of genes facilitating MRSA infection: Staphylococcal commensal species such as Staphylococcus epidermidis are being recognized as important sources of genes promoting MRSA colonization and virulence.

    PubMed

    Otto, Michael

    2013-01-01

    Recent research has suggested that Staphylococcus epidermidis is a reservoir of genes that, after horizontal transfer, facilitate the potential of Staphylococcus aureus to colonize, survive during infection, or resist antibiotic treatment, traits that are notably manifest in methicillin-resistant S. aureus (MRSA). S. aureus is a dangerous human pathogen and notorious for acquiring antibiotic resistance. MRSA in particular is one of the most frequent causes of morbidity and death in hospitalized patients. S. aureus is an extremely versatile pathogen with a multitude of mechanisms to cause disease and circumvent immune defenses. In contrast, most other staphylococci, such as S. epidermidis, are commonly benign commensals and only occasionally cause disease. Recent findings highlight the key importance of efforts to better understand how genes of staphylococci other than S. aureus contribute to survival in the human host, how they are transferred to S. aureus, and why this exchange appears to be uni-directional.

  15. Two pathogenic species of Pythium: P. aphanidermatum and P. diclinum from a wheat field.

    PubMed

    Al-Sheikh, Hashem

    2010-10-01

    During a survey of pathogenic and non-pathogenic Pythium spp. in different localities in Egypt, several isolates of Pythia were obtained and maintained on corn meal agar. Among these isolates, Pythium aphanidermatum and Pythium diclinum were obtained from rhizosphere of wheat plants grown in Dear Attia village, Minia, Egypt. Identification was made using morphological and molecular analyses. P. aphanidermatum and P. diclinum were able to cause reductions in emergence and adulating in wheat in laboratory scale. P. aphanidermatum appeared to be the most aggressive parasite under agar and pot experimental conditions. PMID:23961096

  16. Incidence, Molecular Characteristics and Pathogenicity of Gibberella fujikuroi Species Complex Associated with Rice Seeds from Asian Countries.

    PubMed

    Jeon, Young-Ah; Yu, Seung-Hun; Lee, Young Yi; Park, Hong-Jae; Lee, Sokyoung; Sung, Jung Sook; Kim, Yeon-Gyu; Lee, Ho-Sun

    2013-12-01

    Gibberella fujikuroi species complex (GFSC) was isolated from rice (Oryza sativa L.) seed samples from ten Asian countries and investigated for incidence of GFSC, molecular characteristics, and pathogenicity. Regardless of geographic origin, GFSC was detected with incidences ranging from 3% to 80%. Four species, Fusarium fujikuroi, F. concentricum, F. proliferatum, and F. verticillioides, were found to show an association with rice seeds, with F. fujikuroi being the predominant species. In phylogenetic analyses of DNA sequences, no relationship was found between species, isolates, and geographic sources of samples. Unidentified fragments of the β-tubulin gene were observed in ten isolates of F. fujikuroi and F. verticillioides. With the exception of three isolates of F. fujikuroi, F. fujikuroi, F. proliferatum, and F. verticillioides were found to have FUM1 (the fumonisin biosynthetic gene); however, FUM1 was not found in isolates of F. concentricum. Results of pathogenicity testing showed that all isolates caused reduced germination of rice seed. In addition, F. fujikuroi and F. concentricum caused typical symptoms of bakanae, leaf elongation and chlorosis, whereas F. proliferatum and F. verticillioides only caused stunting of seedlings. These findings provide insight into the characteristics of GFSC associated with rice seeds and might be helpful in development of strategies for management of bakanae.

  17. Candida and Fusarium species known as opportunistic human pathogens from customer-accessible parts of residential washing machines.

    PubMed

    Babič, Monika Novak; Zalar, Polona; Ženko, Bernard; Schroers, Hans-Josef; Džeroski, Sašo; Gunde-Cimerman, Nina

    2015-03-01

    Energy constraints have altered consumer practice regarding the use of household washing machines. Washing machines were developed that use lower washing temperatures, smaller amounts of water and biodegradable detergents. These conditions may favour the enrichment of opportunistic human pathogenic fungi. We focused on the isolation of fungi from two user-accessible parts of washing machines that often contain microbial biofilms: drawers for detergents and rubber door seals. Out of 70 residential washing machines sampled in Slovenia, 79% were positive for fungi. In total, 72 strains belonging to 12 genera and 26 species were isolated. Among these, members of the Fusarium oxysporum and Fusarium solani species complexes, Candida parapsilosis and Exophiala phaeomuriformis represented 44% of fungi detected. These species are known as opportunistic human pathogens and can cause skin, nail or eye infections also in healthy humans. A machine learning analysis revealed that presence of detergents and softeners followed by washing temperature, represent most critical factors for fungal colonization. Three washing machines with persisting malodour that resulted in bad smelling laundry were analysed for the presence of fungi and bacteria. In these cases, fungi were isolated in low numbers (7.5 %), while bacteria Micrococcus luteus, Pseudomonas aeruginosa, and Sphingomonas species prevailed.

  18. Candida and Fusarium species known as opportunistic human pathogens from customer-accessible parts of residential washing machines.

    PubMed

    Babič, Monika Novak; Zalar, Polona; Ženko, Bernard; Schroers, Hans-Josef; Džeroski, Sašo; Gunde-Cimerman, Nina

    2015-03-01

    Energy constraints have altered consumer practice regarding the use of household washing machines. Washing machines were developed that use lower washing temperatures, smaller amounts of water and biodegradable detergents. These conditions may favour the enrichment of opportunistic human pathogenic fungi. We focused on the isolation of fungi from two user-accessible parts of washing machines that often contain microbial biofilms: drawers for detergents and rubber door seals. Out of 70 residential washing machines sampled in Slovenia, 79% were positive for fungi. In total, 72 strains belonging to 12 genera and 26 species were isolated. Among these, members of the Fusarium oxysporum and Fusarium solani species complexes, Candida parapsilosis and Exophiala phaeomuriformis represented 44% of fungi detected. These species are known as opportunistic human pathogens and can cause skin, nail or eye infections also in healthy humans. A machine learning analysis revealed that presence of detergents and softeners followed by washing temperature, represent most critical factors for fungal colonization. Three washing machines with persisting malodour that resulted in bad smelling laundry were analysed for the presence of fungi and bacteria. In these cases, fungi were isolated in low numbers (7.5 %), while bacteria Micrococcus luteus, Pseudomonas aeruginosa, and Sphingomonas species prevailed. PMID:25749362

  19. Staphylococcal manipulation of host immune responses

    PubMed Central

    Thammavongsa, Vilasack; Kim, Hwan Keun; Missiakas, Dominique; Schneewind, Olaf

    2015-01-01

    Staphylococcus aureus, a bacterial commensal of the human nares and skin, is a frequent cause of soft tissue and bloodstream infections. A hallmark of staphylococcal infections is their frequent recurrence, even when treated with antibiotics and surgical intervention, which demonstrates the bacterium’s ability to manipulate innate and adaptive immune responses. In this Review, we highlight how S. aureus virulence factors inhibit complement activation, block and destroy phagocytic cells and modify host B and T cell responses, and we discuss how these insights might be useful for the development of novel therapies against infections with antibiotic resistant strains such as methicillin-resistant S. aureus. PMID:26272408

  20. Evaluation of the pathogenicity and virulence of Yersinia species isolated in Edo and Delta States of Nigeria.

    PubMed

    Igumbor, E O; Ogbimi, A O; Agbonlahor, D E; Obi, C L

    1993-12-01

    Sixteen isolates of four species of Yersinia comprising five of Yersinia enterocolitica and Yersinia fredricksenii, four of Yersinia intermedia and two of Yersinia kristensenii isolated from domestic and wild animals in villages in Edo and Delta States, Nigeria, were evaluated for their pathogenicity using laboratory animal models and virulence characteristics tests which included autoagglutinability, calcium dependency for growth, heat-stable enterotoxin production and conjunctivities in guinea pig eye. Results obtained revealed that Yersinia enterocolitica isolates were enteropathogenic as demonstrated by the production of diarrhoea and eventual recovery from faeces, spleen and liver of the infected animals. Three (60%) (2 serotypes 0:3 and 1 serotype 0:8) of the five Yersinia enterocolitica isolates were lethal to the animals. Other Yersinia isolates (Yersinia kristensenii, Yersinia fredricksenii and Yersinia intermedia) were uniformly non pathogenic to the animals. However, a strain of Yersinia intermedia isolate produced diarrhoea in the inoculated animals and caused lethality in guinea pigs and mice, but was negative for autoagglutination test, calcium dependency, conjunctivities, and positive for heat-stable enterotoxin production. We are of the view that this strain may be another Yersinia intermedia--like bacterium, previously isolated in Nigeria. Results therefore, suggest an emergence of a pathogenic Yersinia intermedia species in this environment.

  1. Rapid species identification of seafood spoilage and pathogenic Gram-positive bacteria by MALDI-TOF mass fingerprinting.

    PubMed

    Böhme, Karola; Fernández-No, Inmaculada C; Barros-Velázquez, Jorge; Gallardo, Jose M; Cañas, Benito; Calo-Mata, Pilar

    2011-11-01

    The rapid identification of food pathogenic and spoilage bacteria is important to ensure food quality and safety. Seafood contaminated with pathogenic bacteria is one of the major causes of food intoxications, and the rapid spoilage of seafood products results in high economic losses. In this study, a collection of the main seafood pathogenic and spoilage Gram-positive bacteria was compiled, including Bacillus spp., Listeria spp., Clostridium spp., Staphylococcus spp. and Carnobacterium spp. The strains, belonging to 20 different species, were obtained from the culture collections and studied by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). A reference library was created, including the spectral fingerprints of 32 reference strains and the extracted peak lists with 10-30 peak masses. Genus-specific as well as species-specific peak masses were assigned and could serve as biomarkers for the rapid bacterial identification. Furthermore, the peak mass lists were clustered with the web-application SPECLUST to show the phyloproteomic relationships among the studied strains. Afterwards, the method was successfully applied to identify six strains isolated from seafood by comparison with the reference library. Additionally, phylogenetic analysis based on the 16S rRNA gene was carried out and contrasted with the proteomic approach. This is the first time MALDI-TOF MS fingerprinting is applied to Gram-positive bacterial identification in seafood, being a fast and accurate technique to ensure seafood quality and safety.

  2. Opportunistic, human-pathogenic species in the Herpotrichiellaceae are phenotypically similar to saprobic or phytopathogenic species in the Venturiaceae

    PubMed Central

    Crous, P.W.; Schubert, K.; Braun, U.; de Hoog, G.S.; Hocking, A.D.; Shin, H.-D.; Groenewald, J.Z.

    2007-01-01

    Although morphologically similar, species of Cladophialophora (Herpotrichiellaceae) were shown to be phylogenetically distinct from Pseudocladosporium (Venturiaceae), which was revealed to be synonymous with the older genus, Fusicladium. Other than being associated with human disorders, species of Cladophialophora were found to also be phytopathogenic, or to occur as saprobes on organic material, or in water, fruit juices, or sports drinks, along with species of Exophiala. Caproventuria and Metacoleroa were confirmed to be synonyms of Venturia, which has Fusicladium (= Pseudocladosporium) anamorphs. Apiosporina, based on A. collinsii, clustered basal to the Venturia clade, and appears to represent a further synonym. Several species with a pseudocladosporium-like morphology in vitro represent a sister clade to the Venturia clade, and are unrelated to Polyscytalum. These taxa are newly described in Fusicladium, which is morphologically close to Anungitea, a heterogeneous genus with unknown phylogenetic affinity. In contrast to the Herpotrichiellaceae, which were shown to produce numerous synanamorphs in culture, species of the Venturiaceae were morphologically and phylogenetically more uniform. Several new species and new combinations were introduced in Cladophialophora, Cyphellophora (Herpotrichiellaceae), Exophiala, Fusicladium, Venturia (Venturiaceae), and Cylindrosympodium (incertae sedis). PMID:18491000

  3. Clinical Significance and Pathogenesis of Staphylococcal Small Colony Variants in Persistent Infections.

    PubMed

    Kahl, Barbara C; Becker, Karsten; Löffler, Bettina

    2016-04-01

    Small colony variants (SCVs) were first described more than 100 years ago for Staphylococcus aureus and various coagulase-negative staphylococci. Two decades ago, an association between chronic staphylococcal infections and the presence of SCVs was observed. Since then, many clinical studies and observations have been published which tie recurrent, persistent staphylococcal infections, including device-associated infections, bone and tissue infections, and airway infections of cystic fibrosis patients, to this special phenotype. By their intracellular lifestyle, SCVs exhibit so-called phenotypic (or functional) resistance beyond the classical resistance mechanisms, and they can often be retrieved from therapy-refractory courses of infection. In this review, the various clinical infections where SCVs can be expected and isolated, diagnostic procedures for optimized species confirmation, and the pathogenesis of SCVs, including defined underlying molecular mechanisms and the phenotype switch phenomenon, are presented. Moreover, relevant animal models and suggested treatment regimens, as well as the requirements for future research areas, are highlighted. PMID:26960941

  4. Tomato response traits to pathogenic Pseudomonas species: Does nitrogen limitation matter?

    PubMed

    Royer, Mathilde; Larbat, Romain; Le Bot, Jacques; Adamowicz, Stéphane; Nicot, Philippe C; Robin, Christophe

    2016-03-01

    Induced chemical defence is a cost-efficient protective strategy, whereby plants induce the biosynthesis of defence-related compounds only in the case of pest attack. Plant responses that are pathogen specific lower the cost of defence, compared to constitutive defence. As nitrogen availability (N) in the root zone is one of the levers mediating the concentration of defence-related compounds in plants, we investigated its influence on response traits of tomato to two pathogenic bacteria, growing plants hydroponically at low or high N supply. Using two sets of plants for each level of N supply, we inoculated one leaf of one set of plants with Pseudomonas syringae, and inoculated the stem of other set of plants with Pseudomonas corrugata. Tomato response traits (growth, metabolites) were investigated one and twelve days after inoculation. In infected areas, P. syringae decreased carbohydrate concentrations whereas they were increased by P. corrugata. P. syringae mediated a redistribution of carbon within the phenylpropanoid pathway, regardless of N supply: phenolamides, especially caffeoylputrescine, were stimulated, impairing defence-related compounds such as chlorogenic acid. Inoculation of P. syringae produced strong and sustainable systemic responses. By contrast, inoculation of P. corrugata induced local and transient responses. The effects of pathogens on plant growth and leaf gas exchanges appeared to be independant of N supply. This work shows that the same genus of plant pathogens with different infection strategies can mediate contrasted plant responses. PMID:26810453

  5. Susceptibility of avian species to north american H13 low pathogenic avian influenza viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gulls are widely recognized reservoirs for low pathogenic avian influenza (LPAI) viruses; however, the subtypes maintained in these populations and/or the transmission mechanisms involved are poorly understood. Although, a wide diversity of influenza viruses have been isolated from gulls, two hemag...

  6. Comparative susceptibility of avian species to low pathogenic avian influenza viruses of the H13 subtype

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gulls are widely recognized reservoirs for low pathogenic avian influenza (LPAI) viruses; however, the subtypes maintained in these populations and/or the transmission mechanisms involved are poorly understood. Although, a wide diversity of influenza viruses have been isolated from gulls, two hemag...

  7. Epidemiological survey of zoonotic pathogens in feral pigeons (Columba livia var. domestica) and sympatric zoo species in Southern Spain.

    PubMed

    Cano-Terriza, David; Guerra, Rafael; Lecollinet, Sylvie; Cerdà-Cuéllar, Marta; Cabezón, Oscar; Almería, Sonia; García-Bocanegra, Ignacio

    2015-12-01

    A cross-sectional study was carried out to determine the prevalence of pathogenic zoonotic agents (flaviviruses, avian influenza viruses (AIVs), Salmonella spp. and Toxoplasma gondii) in feral pigeons and sympatric zoo animals from Córdoba (Southern Spain) between 2013 and 2014. Antibodies against flaviviruses were detected in 7.8% out of 142 (CI95%: 3.7-11.8) pigeons, and 8.2% of 49 (CI95%: 0.9-15.4) of zoo animals tested. Antibodies with specificity against West Nile virus (WNV) and Usutu virus (USUV) were confirmed both in pigeons and in zoo birds. Even though seropositivity to AIVs was not detected in any of the analyzed pigeons, 17.9% of 28 (CI95%: 3.7-32.0) zoo birds tested showed positive results. Salmonella spp. was not isolated in any of 152 fecal samples collected from pigeons, while 6.8% of 44 zoo animals were positive. Antibodies against T. gondii were found in 9.2% of 142 (CI95%: 4.8-13.6) feral pigeons and 26.9% of 108 (CI95%: 19.6-34.1) zoo animals. This is the first study on flaviviruses and T. gondii in feral pigeons and captive zoo species in Spain. Antibodies against WNV and USUV detected in non-migratory pigeons and captive zoo animals indicate local circulation of these emerging pathogens in the study area. T. gondii was widespread in species analyzed. This finding could be of importance for Public Health and Conservation of endangered species present in zoo parks. Pigeons and zoo animals may be included as sentinel species for monitoring zoonotic pathogens in urban areas.

  8. Antimicrobial Activity of neo-Clerodane Diterpenoids isolated from Lamiaceae Species against Pathogenic and Food Spoilage Microorganisms.

    PubMed

    Bozov, Petko; Girova, Tania; Prisadova, Natalia; Hristova, Yana; Gochev, Velizar

    2015-11-01

    Antimicrobial activity of nineteen neo-clerodane diterpenoids, isolated from the acetone extracts of the aerial parts of Scutellaria and Salvia species (Lamiaceae) were tested against thirteen strains belonging to nine different species of pathogenic and food spoilage bacteria Aeromonas hydrophila, Bacillus cereus, Escherichia coli, Listeria monocytogenes, Proteus vulgaris, Pseudomonas aeruginosa, Pseudomonas fluorescens, Salmonella abony and Staphylococcus aureus as well as against two yeast strains belonging to species Candida albicans. Seven of the evaluated compounds scutalpin A, scutalpin E, scutalpin F, salviarin, splenolide A, splenolide B and splendidin demonstrated antimicrobial activity against used test microbial strains, the rest of the compounds were inactive within the studied concentration range. Among all of the tested compounds the highest antimicrobial activity was detected for scutalpin A against Staphylococcus aureus (MIC 25 µg/mL).

  9. Antimicrobial Activity of neo-Clerodane Diterpenoids isolated from Lamiaceae Species against Pathogenic and Food Spoilage Microorganisms.

    PubMed

    Bozov, Petko; Girova, Tania; Prisadova, Natalia; Hristova, Yana; Gochev, Velizar

    2015-11-01

    Antimicrobial activity of nineteen neo-clerodane diterpenoids, isolated from the acetone extracts of the aerial parts of Scutellaria and Salvia species (Lamiaceae) were tested against thirteen strains belonging to nine different species of pathogenic and food spoilage bacteria Aeromonas hydrophila, Bacillus cereus, Escherichia coli, Listeria monocytogenes, Proteus vulgaris, Pseudomonas aeruginosa, Pseudomonas fluorescens, Salmonella abony and Staphylococcus aureus as well as against two yeast strains belonging to species Candida albicans. Seven of the evaluated compounds scutalpin A, scutalpin E, scutalpin F, salviarin, splenolide A, splenolide B and splendidin demonstrated antimicrobial activity against used test microbial strains, the rest of the compounds were inactive within the studied concentration range. Among all of the tested compounds the highest antimicrobial activity was detected for scutalpin A against Staphylococcus aureus (MIC 25 µg/mL). PMID:26749799

  10. Prevalence of Bovine Mastitis Pathogens in Bulk Tank Milk in China

    PubMed Central

    Wang, Ya Jing; Qin, Yun; Guix Vallverdú, Roger; Maldonado García, Jaime; Sun, Wei; Li, Shengli; Cao, Zhijun

    2016-01-01

    The objectives of this study were to estimate the herd prevalence of major mastitis pathogens in bulk tank milk (BTM) in China dairy herds, to determine the relationship between the presence of mastitis pathogens and bulk tank milk somatic cell counts (BTSCC), and to investigate the impact of different dairy cattle farming modes and region on bacterial species. BTM samples collected from 894 dairy herds in China were examined for the presence of mastitis pathogens. The Flinders Technology Associates (FTA) cards were used for BTM sample collection, storage, and transportation and bacterial DNA amplification by real-time PCR. Among contagious pathogens, Staphylococcus aureus, Streptococcus agalactiae, and Streptococcus dysgalactiae were detected in 50.1, 92.2, and 72.3% of the 894 BTM samples, respectively. Among environmental pathogens, E. coli, Streptococcus uberis, Enterococcus spp., Klebsiella spp., Serratia marcescens, Corynebacterium bovis, and Arcanobacterium pyogenes were detected in 28.6, 8.9, 35.7, 20.0, 1.3, 17.0, and 67.2% of the BTM samples, respectively. Staphylococcal β-lactamase gene was detected in 61.7% of the BTM samples. The presence of Staphylococcus aureus and Arcanobacterium pyogenes were significantly associated with high BTSCC, respectively. Significant differences were found in presence of Staphylococcus aureus, Streptococcus agalactiae, and Streptococcus dysgalactiae in BTM sampled from the small household farms, dairy-farming communities, and large-scaled dairy farms. There were significant differences in the presence of Streptococcus agalactiae, Streptococcus dysgalactiae, Arcanobacterium pyogenes, staphylococcal β-lactamase gene, Staphylococcus spp., Klebsiella spp., Enterococcus spp., and Streptococcus uberis in BTM among Inner Mongolia, Heilongjiang, and Hebei province. In conclusion, contagious mammary pathogens are predominated among pathogens in BTM samples in China. PMID:27187065

  11. Prevalence of Bovine Mastitis Pathogens in Bulk Tank Milk in China.

    PubMed

    Bi, Yanliang; Wang, Ya Jing; Qin, Yun; Guix Vallverdú, Roger; Maldonado García, Jaime; Sun, Wei; Li, Shengli; Cao, Zhijun

    2016-01-01

    The objectives of this study were to estimate the herd prevalence of major mastitis pathogens in bulk tank milk (BTM) in China dairy herds, to determine the relationship between the presence of mastitis pathogens and bulk tank milk somatic cell counts (BTSCC), and to investigate the impact of different dairy cattle farming modes and region on bacterial species. BTM samples collected from 894 dairy herds in China were examined for the presence of mastitis pathogens. The Flinders Technology Associates (FTA) cards were used for BTM sample collection, storage, and transportation and bacterial DNA amplification by real-time PCR. Among contagious pathogens, Staphylococcus aureus, Streptococcus agalactiae, and Streptococcus dysgalactiae were detected in 50.1, 92.2, and 72.3% of the 894 BTM samples, respectively. Among environmental pathogens, E. coli, Streptococcus uberis, Enterococcus spp., Klebsiella spp., Serratia marcescens, Corynebacterium bovis, and Arcanobacterium pyogenes were detected in 28.6, 8.9, 35.7, 20.0, 1.3, 17.0, and 67.2% of the BTM samples, respectively. Staphylococcal β-lactamase gene was detected in 61.7% of the BTM samples. The presence of Staphylococcus aureus and Arcanobacterium pyogenes were significantly associated with high BTSCC, respectively. Significant differences were found in presence of Staphylococcus aureus, Streptococcus agalactiae, and Streptococcus dysgalactiae in BTM sampled from the small household farms, dairy-farming communities, and large-scaled dairy farms. There were significant differences in the presence of Streptococcus agalactiae, Streptococcus dysgalactiae, Arcanobacterium pyogenes, staphylococcal β-lactamase gene, Staphylococcus spp., Klebsiella spp., Enterococcus spp., and Streptococcus uberis in BTM among Inner Mongolia, Heilongjiang, and Hebei province. In conclusion, contagious mammary pathogens are predominated among pathogens in BTM samples in China. PMID:27187065

  12. Gene Network Polymorphism Illuminates Loss and Retention of Novel RNAi Silencing Components in the Cryptococcus Pathogenic Species Complex

    PubMed Central

    Clancey, Shelly Applen; Wang, Xuying; Heitman, Joseph

    2016-01-01

    RNAi is a ubiquitous pathway that serves central functions throughout eukaryotes, including maintenance of genome stability and repression of transposon expression and movement. However, a number of organisms have lost their RNAi pathways, including the model yeast Saccharomyces cerevisiae, the maize pathogen Ustilago maydis, the human pathogen Cryptococcus deuterogattii, and some human parasite pathogens, suggesting there may be adaptive benefits associated with both retention and loss of RNAi. By comparing the RNAi-deficient genome of the Pacific Northwest Outbreak C. deuterogattii strain R265 with the RNAi-proficient genomes of the Cryptococcus pathogenic species complex, we identified a set of conserved genes that were lost in R265 and all other C. deuterogattii isolates examined. Genetic and molecular analyses reveal several of these lost genes play roles in RNAi pathways. Four novel components were examined further. Znf3 (a zinc finger protein) and Qip1 (a homolog of N. crassa Qip) were found to be essential for RNAi, while Cpr2 (a constitutive pheromone receptor) and Fzc28 (a transcription factor) are involved in sex-induced but not mitosis-induced silencing. Our results demonstrate that the mitotic and sex-induced RNAi pathways rely on the same core components, but sex-induced silencing may be a more specific, highly induced variant that involves additional specialized or regulatory components. Our studies further illustrate how gene network polymorphisms involving known components of key cellular pathways can inform identification of novel elements and suggest that RNAi loss may have been a core event in the speciation of C. deuterogattii and possibly contributed to its pathogenic trajectory. PMID:26943821

  13. Identification of Regions of the Chromosome of Neisseria meningitidis and Neisseria gonorrhoeae Which Are Specific to the Pathogenic Neisseria Species

    PubMed Central

    Perrin, Agnes; Nassif, Xavier; Tinsley, Colin

    1999-01-01

    Neisseria meningitidis and Neisseria gonorrhoeae give rise to dramatically different diseases. Their interactions with the host, however, do share common characteristics: they are both human pathogens which do not survive in the environment and which colonize and invade mucosa at their port of entry. It is therefore likely that they have common properties that might not be found in nonpathogenic bacteria belonging to the same genetically related group, such as Neisseria lactamica. Their common properties may be determined by chromosomal regions found only in the pathogenic Neisseria species. To address this issue, we used a previously described technique (C. R. Tinsley and X. Nassif, Proc. Natl. Acad. Sci. USA 93:11109–11114, 1996) to identify sequences of DNA specific for pathogenic neisseriae and not found in N. lactamica. Sequences present in N. lactamica were physically subtracted from the N. meningitidis Z2491 sequence and also from the N. gonorrhoeae FA1090 sequence. The clones obtained from each subtraction were tested by Southern blotting for their reactivity with the three species, and only those which reacted with both N. meningitidis and N. gonorrhoeae (i.e., not specific to either one of the pathogens) were further investigated. In a first step, these clones were mapped onto the chromosomes of both N. meningitidis and N. gonorrhoeae. The majority of the clones were arranged in clusters extending up to 10 kb, suggesting the presence of chromosomal regions common to N. meningitidis and N. gonorrhoeae which distinguish these pathogens from the commensal N. lactamica. The sequences surrounding these clones were determined from the N. meningitidis genome-sequencing project. Several clones corresponded to previously described factors required for colonization and survival at the port of entry, such as immunoglobulin A protease and PilC. Others were homologous to virulence-associated proteins in other bacteria, demonstrating that the subtractive clones are

  14. Phytophthora species recovered from irrigation reservoirs in Mississippi and Alabama nurseries and pathogenicity of three new species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    From a survey of containment ponds for Phytophthora spp. at one nursery each in Alabama and Mississippi, eight species and one taxon were recovered with P. gonapodyides dominant in cooler months and P. hydropathica in warmer months, accounting for 39.6% and 46.6% overall recovery, respectively. Amo...

  15. Phytophthora species recovered from irrigation reservoirs in Mississippi and Alabama nurseries and pathogenicity of three new species.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    From a survey of containment ponds for Phytophthora spp. at one nursery each in Alabama and Mississippi, eight species and one taxon were recovered with P. gonapodyides dominant in cooler months and P. hydropathica in warmer months, accounting for 39.6% and 46.6% overall recovery, respectively. Amo...

  16. Strategies for the Identification and Tracking of Cronobacter Species: An Opportunistic Pathogen of Concern to Neonatal Health

    PubMed Central

    Yan, Qiongqiong; Fanning, Séamus

    2015-01-01

    Cronobacter species are emerging opportunistic food-borne pathogens, which consists of seven species, including C. sakazakii, C. malonaticus, C. muytjensii, C. turicensis, C. dublinensis, C. universalis, and C. condimenti. The organism can cause severe clinical infections, including necrotizing enterocolitis, septicemia, and meningitis, predominately among neonates <4 weeks of age. Cronobacter species can be isolated from various foods and their surrounding environments; however, powdered infant formula (PIF) is the most frequently implicated food source linked with Cronobacter infection. This review aims to provide a summary of laboratory-based strategies that can be used to identify and trace Cronobacter species. The identification of Cronobacter species using conventional culture method and immuno-based detection protocols were first presented. The molecular detection and identification at genus-, and species-level along with molecular-based serogroup approaches are also described, followed by the molecular sub-typing methods, in particular pulsed-field gel electrophoresis and multi-locus sequence typing. Next generation sequence approaches, including whole genome sequencing, DNA microarray, and high-throughput whole-transcriptome sequencing, are also highlighted. Appropriate application of these strategies would contribute to reduce the risk of Cronobacter contamination in PIF and production environments, thereby improving food safety and protecting public health. PMID:26000266

  17. An outbreak of low pathogenic avian influenza in a mixed-species aviculture unit in Dubai in 2005.

    PubMed

    Kent, Jo; Bailey, Tom; Silvanose, Christu-Das; McKeown, Sean; Wernery, Ulrich; Kinne, Joerg; Manvell, Ruth

    2006-09-01

    This case describes an outbreak of low pathogenic hemagglutinin 9 neuraminidase 2 avian influenza virus (AIV) in two white-bellied bustards (Eupodotis senegalensis), one stone curlew (Burhinus oedicnemius), and a blacksmith plover (Antibyx armatus) in a private zoologic collection in Dubai, United Arab Emirates. The four birds showed signs of respiratory disease, and all died as a result of disease or euthanasia. Attention has been paid to the diagnostic process and common differential diagnosis for upper respiratory tract disease in bustards, curlews, and plovers. To the knowledge of the authors, AIV has not been previously described in these species.

  18. Survival of three species of anuran metamorphs exposed to UV-B radiation and the pathogenic fungus Batrachochytrium dendrobatidis.

    PubMed

    Garcia, T S; Romansic, J M; Blaustein, A R

    2006-10-17

    When exploring the possible factors contributing to population declines, it is necessary to consider multiple, interacting environmental stressors. Here, we investigate the impact of 2 factors, ultraviolet radiation and disease, on the survival of anuran amphibians. Exposure to ultraviolet-B (UV-B) radiation increases mortality and results in various sub-lethal effects for many amphibian species. Infectious diseases can also negatively impact amphibian populations. In this study, we exposed metamorphic individuals (metamorphs) to both UV-B and Batrachochytrium dendrobatidis (BD), a fungal pathogen and cause of the disease chytridiomycosis, and monitored survival for 3 wk. We tested for possible interactions between UV-B and BD in 3 species: the Cascades frog Rana cascadae; the Western toad Bufo boreas; and the Pacific treefrog Hyla regilla. We found strong interspecific differences in susceptibility to BD. For example, R. cascadae suffered a large increase in mortality when exposed to BD; B. boreas also experienced mortality, but this effect was small relative to the R. cascadae response. H. regilla did not show any decrease in survival when exposed to either factor. No synergistic interactions between UV-B and BD were found for any of the test species. A previous study investigating the impact of BD on larval amphibians showed different species responses (Blaustein et al. 2005a). Our results highlight the importance of studying multiple life history stages when determining the impact of environmental stressors. The contrast between these 2 studies emphasizes how vulnerability to a pathogen can vary between life history stages within a single species. PMID:17140139

  19. Pathogenicity and virulence of Pythium species obtained from forest nursery soils on Douglas-fir seedlings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pythium species are common soilborne oomycetes that occur in forest nursery soils in the Pacific Northwest (PNW) region of the United States. Numerous species have been described. However, with the exception of P. aphanidermatum, P. irregulare, P.mamillatum, and P. ultimum, little is known about the...

  20. Pythium species causing damping-off of alfalfa in Minnesota: Identification, pathogenicity and fungicide sensitivity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Damping-off and seed rot is an important disease of alfalfa, severely affecting stand establishment when conditions favor the disease. Globally, 15 Pythium species are reported to cause damping-off and seed rot of alfalfa, although surveys of species causing disease on alfalfa in Minnesota are lacki...

  1. Staphylococcal Esx Proteins Modulate Apoptosis and Release of Intracellular Staphylococcus aureus during Infection in Epithelial Cells

    PubMed Central

    Korea, Charalampia G.; Balsamo, Giuliana; Pezzicoli, Alfredo; Merakou, Christina; Tavarini, Simona; Bagnoli, Fabio; Serruto, Davide

    2014-01-01

    The opportunistic pathogen Staphylococcus aureus is one of the major causes of health care-associated infections. S. aureus is primarily an extracellular pathogen, but it was recently reported to invade and replicate in several host cell types. The ability of S. aureus to persist within cells has been implicated in resistance to antimicrobials and recurrent infections. However, few staphylococcal proteins that mediate intracellular survival have been identified. Here we examine if EsxA and EsxB, substrates of the ESAT-6-like secretion system (Ess), are important during intracellular S. aureus infection. The Esx proteins are required for staphylococcal virulence, but their functions during infection are unclear. While isogenic S. aureus esxA and esxB mutants were not defective for epithelial cell invasion in vitro, a significant increase in early/late apoptosis was observed in esxA mutant-infected cells compared to wild-type-infected cells. Impeding secretion of EsxA by deleting C-terminal residues of the protein also resulted in a significant increase of epithelial cell apoptosis. Furthermore, cells transfected with esxA showed an increased protection from apoptotic cell death. A double mutant lacking both EsxA and EsxB also induced increased apoptosis but, remarkably, was unable to escape from cells as efficiently as the single mutants or the wild type. Thus, using in vitro models of intracellular staphylococcal infection, we demonstrate that EsxA interferes with host cell apoptotic pathways and, together with EsxB, mediates the release of S. aureus from the host cell. PMID:25047846

  2. Nutritional physiology and taxonomy of human-pathogenic Cladosporium-Xylohypha species.

    PubMed

    de Hoog, G S; Guého, E; Masclaux, F; Gerrits van den Ende, A H; Kwon-Chung, K J; McGinnis, M R

    1995-01-01

    Physiological profiles of type, authentic and some additional isolates of Cladosporium-Xylohypha species of purported herpotrichiellaceous relationship are established. This group comprises melanized catenate hyphomycetes which are prevalently found on the human host. The species are excluded from the genus Cladosporium and are classified in the genus Cladophialophora. Taeniolella boppii is also transferred to this genus. Cladosporium bantianum (= Xylohypha emmonsii) and C. trichoides are considered conspecific and are now referred to as Cladophialophora bantiana. Meso-erythritol, L-arabinitol, ethanol and growth at 40 degrees C are found to be the most useful criteria for species distinction. The species Cladosporium carrionii is found to be heterogeneous. The anamorph of the saprophytic ascomycete Capronia pilosella is morphologically similar to an authentic strain of Cladosporium carrionii, but physiologically distinct. A diagnostic key for the recognized Cladophialophora species and to morphologically similar taxa is provided.

  3. Probabilistic risk model for staphylococcal intoxication from pork-based food dishes prepared in food service establishments in Korea.

    PubMed

    Kim, Hyun Jung; Griffiths, Mansel W; Fazil, Aamir M; Lammerding, Anna M

    2009-09-01

    Foodborne illness contracted at food service operations is an important public health issue in Korea. In this study, the probabilities for growth of, and enterotoxin production by, Staphylococcus aureus in pork meat-based foods prepared in food service operations were estimated by the Monte Carlo simulation. Data on the prevalence and concentration of S. aureus as well as compliance to guidelines for time and temperature controls during food service operations were collected. The growth of S. aureus was initially estimated by using the U.S. Department of Agriculture's Pathogen Modeling Program. A second model based on raw pork meat was derived to compare cell number predictions. The correlation between toxin level and cell number as well as minimum toxin dose obtained from published data was adopted to quantify the probability of staphylococcal intoxication. When data gaps were found, assumptions were made based on guidelines for food service practices. Baseline risk model and scenario analyses were performed to indicate possible outcomes of staphylococcal intoxication under the scenarios generated based on these data gaps. Staphylococcal growth was predicted during holding before and after cooking, and the highest estimated concentration (4.59 log CFU/g for the 99.9th percentile value) of S. aureus was observed in raw pork initially contaminated with S. aureus and held before cooking. The estimated probability for staphylococcal intoxication was very low, using currently available data. However, scenario analyses revealed an increased possibility of staphylococcal intoxication when increased levels of initial contamination in the raw meat, andlonger holding time both before and after cooking the meat occurred.

  4. Comparative Genomics of the Staphylococcus intermedius Group of Animal Pathogens

    PubMed Central

    Ben Zakour, Nouri L.; Beatson, Scott A.; van den Broek, Adri H. M.; Thoday, Keith L.; Fitzgerald, J. Ross

    2012-01-01

    The Staphylococcus intermedius group consists of three closely related coagulase-positive bacterial species including S. intermedius, Staphylococcus pseudintermedius, and Staphylococcus delphini. S. pseudintermedius is a major skin pathogen of dogs, which occasionally causes severe zoonotic infections of humans. S. delphini has been isolated from an array of different animals including horses, mink, and pigeons, whereas S. intermedius has been isolated only from pigeons to date. Here we provide a detailed analysis of the S. pseudintermedius whole genome sequence in comparison to high quality draft S. intermedius and S. delphini genomes, and to other sequenced staphylococcal species. The core genome of the SIG was highly conserved with average nucleotide identity (ANI) between the three species of 93.61%, which is very close to the threshold of species delineation (95% ANI), highlighting the close-relatedness of the SIG species. However, considerable variation was identified in the content of mobile genetic elements, cell wall-associated proteins, and iron and sugar transporters, reflecting the distinct ecological niches inhabited. Of note, S. pseudintermedius ED99 contained a clustered regularly interspaced short palindromic repeat locus of the Nmeni subtype and S. intermedius contained both Nmeni and Mtube subtypes. In contrast to S. intermedius and S. delphini and most other staphylococci examined to date, S. pseudintermedius contained at least nine predicted reverse transcriptase Group II introns. Furthermore, S. pseudintermedius ED99 encoded several transposons which were largely responsible for its multi-resistant phenotype. Overall, the study highlights extensive differences in accessory genome content between closely related staphylococcal species inhabiting distinct host niches, providing new avenues for research into pathogenesis and bacterial host-adaptation. PMID:22919635

  5. Lactobacilli require physical contact to reduce staphylococcal TSST-1 secretion and vaginal epithelial inflammatory response.

    PubMed

    Younes, Jessica A; Reid, Gregor; van der Mei, Henny C; Busscher, Henk J

    2016-06-01

    ITALIC! Staphylococcus aureusbiofilms can be found on vaginal epithelia, secreting toxins and causing inflammation. The co-vaginal species ITALIC! Lactobacilluscan alter staphylococcal-induced epithelial secretion of inflammatory cytokines and quench staphylococcal toxic shock syndrome toxin-1 secretion. It is hypothesized that these effects of lactobacilli require direct physical contact between lactobacilli, staphylococci and the epithelium. Indeed, lactobacilli only reduced ITALIC! S. aureus-induced inflammatory cytokine expression when allowed physical contact with vaginal epithelial cells. Furthermore, a reduction in toxic shock syndrome toxin-1 secretion only occurred when a probiotic ITALIC! Lactobacillusstrain was allowed contact, but not when being physically separated from ITALIC! S. aureus Bacterial-probe atomic force microscopy demonstrated that lactobacilli and staphylococci strongly adhere to epithelial cells, while lactobacilli adhere stronger to staphylococci than staphylococci to each other, giving lactobacilli opportunity to penetrate and reside in staphylococcal biofilms, as visualized using confocal laser scanning microscopy with fluorescence ITALIC! in situhybridization probes. These results identify that physical contact and biochemical signaling by lactobacilli are intrinsically linked mechanisms that reduce virulence of ITALIC! S. aureusbiofilm.

  6. Molecular and pathogenic variation within Melampsora on Salix in western North America reveals numerous cryptic species.

    PubMed

    Bennett, Chandalin; Aime, M Catherine; Newcombe, George

    2011-01-01

    In North America Melampsora rusts that parasitize willows (Salix species) have never been adequately studied and mostly have been referred to a collective species, Melampsora epitea (Kunze & Schm.) Thüm, of European origin. Even taxa that are nominally distinct from M. epitea, such as M. abieti-caprearum and M. paradoxa, currently are considered to be "races" of M. epitea. Within the range of our field surveys and collections in the Pacific Northwest and the Southwest only two species of Melampsora thus were expected: M. epitea (including its races) and M. ribesii-purpureae. In this study of Melampsora on 19 species of Salix in the western United States 14 phylogenetic species, or phylotypes, were apparent from nuclear rDNA sequencing of 140 collections or isolates. Our collections of the races of M. epitea, M. abieti-caprearum and M. epitea f. sp. tsugae belonged to one phylotype, termed lineage 'N'. Assuming that M. ribesii-purpureae represents one other phylotype, 12 phylotypes still are unaccounted for by current taxonomy. Moreover Eurasian M. ribesii-purpureae was not closely related to any of the phylotypes reported here. Even more problematic was the resistance of Eurasian species of Salix, including the type host of M. epitea, S. alba, to North American Melampsora, including phylotype 'N', in both the field and in inoculation experiments. These results suggest the need for the description of many new species of Melampsora on Salix in western North America. Additional analyses presented here might guide further research in this direction.

  7. Dangerous Liaisons: Caspase-11 and Reactive Oxygen Species Crosstalk in Pathogen Elimination

    PubMed Central

    Roberts, JoAnn Simone; Yilmaz, Ӧzlem

    2015-01-01

    Recently, the focus of murine caspase-11 and human orthologs caspase-4, -5 research has been on their novel function to induce noncanonical inflammasome activation in direct response to Gram-negative bacterial infection. On the other hand, a new role in anti-bacterial autophagy has been attributed to caspase-11, -4 and -5, which currently stands largely unexplored. In this review, we connect lately emerged evidence that suggests these caspases have a key role in anti-bacterial autophagy and discuss the growing implications of a danger molecule—extracellular ATP—and NADPH oxidase-mediated ROS generation as novel inducers of human caspase-4, -5 signaling during infection. We also highlight the adeptness of persistent pathogens like Porphyromonas gingivalis, a Gram-negative anaerobe and successful colonizer of oral mucosa, to potentially interfere with the activated caspase-4 pathway and autophagy. While, the ability of caspase-4, -5 to promote autophagolysosomal fusion is not well understood, the abundance of caspase-4 in skin and other mucosal epithelial cells implies an important role for caspase-4 in mucosal defense, supporting the view that caspase-4, -5 may play a non-redundant part in innate immunity. Thus, this review will join the currently disconnected cutting-edge research thereby proposing a working model for regulation of caspase-4, -5 in pathogen elimination via cellular-trafficking. PMID:26426007

  8. Full Genome Sequence Analysis of Two Isolates Reveals a Novel Xanthomonas Species Close to the Sugarcane Pathogen Xanthomonas albilineans

    PubMed Central

    Pieretti, Isabelle; Cociancich, Stéphane; Bolot, Stéphanie; Carrère, Sébastien; Morisset, Alexandre; Rott, Philippe; Royer, Monique

    2015-01-01

    Xanthomonas albilineans is the bacterium responsible for leaf scald, a lethal disease of sugarcane. Within the Xanthomonas genus, X. albilineans exhibits distinctive genomic characteristics including the presence of significant genome erosion, a non-ribosomal peptide synthesis (NRPS) locus involved in albicidin biosynthesis, and a type 3 secretion system (T3SS) of the Salmonella pathogenicity island-1 (SPI-1) family. We sequenced two X. albilineans-like strains isolated from unusual environments, i.e., from dew droplets on sugarcane leaves and from the wild grass Paspalum dilatatum, and compared these genomes sequences with those of two strains of X. albilineans and three of Xanthomonas sacchari. Average nucleotide identity (ANI) and multi-locus sequence analysis (MLSA) showed that both X. albilineans-like strains belong to a new species close to X. albilineans that we have named “Xanthomonas pseudalbilineans”. X. albilineans and “X. pseudalbilineans” share many genomic features including (i) the lack of genes encoding a hypersensitive response and pathogenicity type 3 secretion system (Hrp-T3SS), and (ii) genome erosion that probably occurred in a common progenitor of both species. Our comparative analyses also revealed specific genomic features that may help X. albilineans interact with sugarcane, e.g., a PglA endoglucanase, three TonB-dependent transporters and a glycogen metabolism gene cluster. Other specific genomic features found in the “X. pseudalbilineans” genome may contribute to its fitness and specific ecological niche. PMID:26213974

  9. Antibiotics and the expression of staphylococcal virulence.

    PubMed

    Gemmell, C G

    1995-08-01

    The last 25 years have witnessed a continuing interest in staphylococci as causes of human infection even though over 100 years have elapsed since their discovery. This has been due in part to the recognition of new disease entities such as scalded skin syndrome, toxic shock syndrome and various infections due to coagulase-negative staphylococci. Development of antimicrobial agents has not solved the problem of these infections partly because of their mediation by novel toxins and partly due to the emergence of multiple drug resistance. However study of the interaction between certain antibiotics and staphylococci in vitro and in vivo has provided new knowledge concerning the role of cell wall-associated and soluble virulence factors in the pathogenesis of staphylococcal disease.

  10. Structural insights into species-specific features of the ribosome from the pathogen Staphylococcus aureus.

    PubMed

    Eyal, Zohar; Matzov, Donna; Krupkin, Miri; Wekselman, Itai; Paukner, Susanne; Zimmerman, Ella; Rozenberg, Haim; Bashan, Anat; Yonath, Ada

    2015-10-27

    The emergence of bacterial multidrug resistance to antibiotics threatens to cause regression to the preantibiotic era. Here we present the crystal structure of the large ribosomal subunit from Staphylococcus aureus, a versatile Gram-positive aggressive pathogen, and its complexes with the known antibiotics linezolid and telithromycin, as well as with a new, highly potent pleuromutilin derivative, BC-3205. These crystal structures shed light on specific structural motifs of the S. aureus ribosome and the binding modes of the aforementioned antibiotics. Moreover, by analyzing the ribosome structure and comparing it with those of nonpathogenic bacterial models, we identified some unique internal and peripheral structural motifs that may be potential candidates for improving known antibiotics and for use in the design of selective antibiotic drugs against S. aureus. PMID:26464510

  11. Structural insights into species-specific features of the ribosome from the pathogen Staphylococcus aureus

    PubMed Central

    Eyal, Zohar; Matzov, Donna; Krupkin, Miri; Wekselman, Itai; Paukner, Susanne; Zimmerman, Ella; Rozenberg, Haim; Bashan, Anat; Yonath, Ada

    2015-01-01

    The emergence of bacterial multidrug resistance to antibiotics threatens to cause regression to the preantibiotic era. Here we present the crystal structure of the large ribosomal subunit from Staphylococcus aureus, a versatile Gram-positive aggressive pathogen, and its complexes with the known antibiotics linezolid and telithromycin, as well as with a new, highly potent pleuromutilin derivative, BC-3205. These crystal structures shed light on specific structural motifs of the S. aureus ribosome and the binding modes of the aforementioned antibiotics. Moreover, by analyzing the ribosome structure and comparing it with those of nonpathogenic bacterial models, we identified some unique internal and peripheral structural motifs that may be potential candidates for improving known antibiotics and for use in the design of selective antibiotic drugs against S. aureus. PMID:26464510

  12. Novel staphylococcal species that form part of a Staphylococcus aureus-related complex: the non-pigmented Staphylococcus argenteus sp. nov. and the non-human primate-associated Staphylococcus schweitzeri sp. nov.

    PubMed

    Tong, Steven Y C; Schaumburg, Frieder; Ellington, Matthew J; Corander, Jukka; Pichon, Bruno; Leendertz, Fabian; Bentley, Stephen D; Parkhill, Julian; Holt, Deborah C; Peters, Georg; Giffard, Philip M

    2015-01-01

    We define two novel species of the genus Staphylococcus that are phenotypically similar to and have near identical 16S rRNA gene sequences to Staphylococcus aureus. However, compared to S. aureus and each other, the two species, Staphylococcus argenteus sp. nov. (type strain MSHR1132(T) = DSM 28299(T) = SSI 89.005(T)) and Staphylococcus schweitzeri sp. nov. (type strain FSA084(T) = DSM 28300(T) = SSI 89.004(T)), demonstrate: 1) at a whole-genome level considerable phylogenetic distance, lack of admixture, average nucleotide identity <95 %, and inferred DNA-DNA hybridization <70 %; 2) different profiles as determined by MALDI-TOF MS; 3) a non-pigmented phenotype for S. argenteus sp. nov.; 4) S. schweitzeri sp. nov. is not detected by standard nucA PCR; 5) distinct peptidoglycan types compared to S. aureus; 6) a separate ecological niche for S. schweitzeri sp. nov.; and 7) a distinct clinical disease profile for S. argenteus sp. nov. compared to S. aureus.

  13. Catecholamines and in vitro growth of pathogenic bacteria: enhancement of growth varies greatly among bacterial species

    NASA Technical Reports Server (NTRS)

    Belay, Tesfaye; Aviles, Hernan; Vance, Monique; Fountain, Kimberly; Sonnenfeld, Gerald

    2003-01-01

    The purpose of this study was to examine the effects of catecholamines on in vitro growth of a range of bacterial species, including anaerobes. Bacteria tested included: Porphyromonas gingivalis, Bacteriodes fragilis, Shigella boydii, Shigella sonnie, Enterobacter Sp, and Salmonella choleraesuis. The results of the current study indicated that supplementation of bacterial cultures in minimal medium with norepinephrine or epinephrine did not result in increased growth of bacteria. Positive controls involving treatment of Escherichia coli with catecholamines did result in increased growth of that bacterial species. The results of the present study extend previous observations that showed differential capability of catecholamines to enhance bacterial growth in vitro.

  14. Comparative antigenic analysis of pathogenic and free-living Naegleria species by the gel diffusion and immunoelectrophoresis techniques.

    PubMed Central

    Visvesvara, G S; Healy, G R

    1975-01-01

    Antigens prepared from each of five strains (CA, CJ, HB-1, HB-3, and TY) of pathogenic Naegleria and the EG strain of nonpathogenic Naegleria gruberi were compared by the gel diffusion and immunoelectrophoresis techniques. Axenically grown amoebae were used as sources of antigens. Antisera were produced in individual rabbits against three strains (CA, CJ, and HB-1) of pathogenic Naegleria and the EG strain of N. gruberi. In the gel diffusion experiment each of the six antigens was reacted with each of the four antisera in agar gel. The results of these experiments revealed that the antigens of N. gruberi reacted strongly with the homologous antiserum but minimally with each of the three heterologous antisera. The antigens of all five pathogenic strains reacted extensively with the anti-CA, anti-CJ, and anti-HB-1 sera and moderately with the anti-EG serum. In the immunoelectrophoresis test each of the six antigens was separated electrophoretically in agar gel and reacted with each of the four antisera. The EG strain reacted extensively with its homologous antiserum and produced multiple precipitin arcs; it reacted minimally with anti-CA, anti-CJ, and anti-HB-1 sera and produced only three arcs. The antigens of all five strains of Naegleria fowleri reacted very strongly with anti-CA, anti-CJ, and anti-HB-1 sera and produced multiple precipitin arcs. They, however, reacted variably with the anti-EG serum and produced three to six precipitin arcs. Comparative immunoelectrophoretic analysis carried out on the CA and HB-1 strains revealed the antigenic identity of these two strains. Based on these results, together with those from the reciprocal absorption experiments, it was concluded that (i) the pathogenic strains of Naegleria, though they shared three to six common antigens with N. gruberi, were nevertheless distinct from it, and (ii) the five pathogenic strains were antigenically close and belonged in the same species. Antigens of Acanthamoeba castellanii, A

  15. Resistance of closely-mown fine fescue and bentgrass species to snow mold pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Creeping bentgrass (Agrostis stolonifera) is the primary species used on golf courses in temperate regions but requires prophylactic fungicide treatment to prevent snow mold diseases. We hypothesized that fine fescues (Festuca spp.) and colonial bentgrass (A. capillaris) have superior resistance to...

  16. Identification of Pathogenic Rare Yeast Species in Clinical Samples: Comparison between Phenotypical and Molecular Methods▿

    PubMed Central

    Cendejas-Bueno, Emilio; Gomez-Lopez, Alicia; Mellado, Emilia; Rodriguez-Tudela, Juan L.; Cuenca-Estrella, Manuel

    2010-01-01

    Species identification using both phenotypic and molecular methods and antifungal susceptibility tests was carried out with 60 uncommon clinical yeasts. Our data show that phenotypic methods were insufficient for correct identification (only 25%) and that most of the wrongly identified strains showed a resistant antifungal profile. PMID:20237094

  17. Species diversity, pathogenicity and toxigenicity of Fusarium associated with rice seeds in Brazil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium is commonly reported in association with rice seeds in Brazil, but knowledge on the species diversity and toxigenic potential is lacking. Such information is critical because maximum limits for Fusarium mycotoxins were set for Brazilian rice in 2011. Ninety-eight rice seed samples from the ...

  18. Comparative genomics of the Fusarium fujikuroi species complex: biosynthetic pathways metabolite production and plant pathogenicity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium is a huge genus of filamentous fungi causing plant diseases in a wide range of host plants that result in high economic losses to world agriculture every year. Phylogenetic studies have shown that the genus Fusarium consists of different species complexes. One of them is the “Fusarium fujik...

  19. Identifying the Achilles heel of multi-host pathogens: the concept of keystone ‘host’ species illustrated by Mycobacterium ulcerans transmission

    NASA Astrophysics Data System (ADS)

    Roche, Benjamin; Benbow, M. Eric; Merritt, Richard; Kimbirauskas, Ryan; McIntosh, Mollie; Small, Pamela L. C.; Williamson, Heather; Guégan, Jean-François

    2013-12-01

    Pathogens that use multiple host species are an increasing public health issue due to their complex transmission, which makes them difficult to mitigate. Here, we explore the possibility of using networks of ecological interactions among potential host species to identify the particular disease-source species to target to break down transmission of such pathogens. We fit a mathematical model on prevalence data of Mycobacterium ulcerans in western Africa and we show that removing the most abundant taxa for this category of pathogen is not an optimal strategy to decrease the transmission of the mycobacterium within aquatic ecosystems. On the contrary, we reveal that the removal of some taxa, especially Oligochaeta worms, can clearly reduce rates of pathogen transmission, and these should be considered as keystone organisms for its transmission because they lead to a substantial reduction in pathogen prevalence regardless of the network topology. Besides their potential application for the understanding of M. ulcerans ecology, we discuss how networks of species interactions can modulate transmission of multi-host pathogens.

  20. Multi-locus tree and species tree approaches toward resolving a complex clade of downy mildews (Straminipila, Oomycota), including pathogens of beet and spinach.

    PubMed

    Choi, Young-Joon; Klosterman, Steven J; Kummer, Volker; Voglmayr, Hermann; Shin, Hyeon-Dong; Thines, Marco

    2015-05-01

    Accurate species determination of plant pathogens is a prerequisite for their control and quarantine, and further for assessing their potential threat to crops. The family Peronosporaceae (Straminipila; Oomycota) consists of obligate biotrophic pathogens that cause downy mildew disease on angiosperms, including a large number of cultivated plants. In the largest downy mildew genus Peronospora, a phylogenetically complex clade includes the economically important downy mildew pathogens of spinach and beet, as well as the type species of the genus Peronospora. To resolve this complex clade at the species level and to infer evolutionary relationships among them, we used multi-locus phylogenetic analysis and species tree estimation. Both approaches discriminated all nine currently accepted species and revealed four previously unrecognized lineages, which are specific to a host genus or species. This is in line with a narrow species concept, i.e. that a downy mildew species is associated with only a particular host plant genus or species. Instead of applying the dubious name Peronospora farinosa, which has been proposed for formal rejection, our results provide strong evidence that Peronospora schachtii is an independent species from lineages on Atriplex and apparently occurs exclusively on Beta vulgaris. The members of the clade investigated, the Peronospora rumicis clade, associate with three different host plant families, Amaranthaceae, Caryophyllaceae, and Polygonaceae, suggesting that they may have speciated following at least two recent inter-family host shifts, rather than contemporary cospeciation with the host plants. PMID:25772799

  1. [Trichophyton species of Arthroderma benhamiae : Clinical therapeutic aspects of a new pathogen in dermatology].

    PubMed

    Hiernickel, C; Wiegand, C; Schliemann, S; Seyfarth, F; Jung, K; Elsner, P; Hipler, U-C

    2016-09-01

    Cutaneous infections with Trichophyton species of Arthroderma (A.) benhamiae are increasingly being detected in Germany. This dermatophyte typically causes tinea corporis, tinea faciei or tinea capitis with in part heavy clinical manifestation like kerion celsi. In special cases diagnosis and therapy can be difficult. In this article, four clinical cases are presented, whereby attention is given to special clinical situations and therapeutic aspects with regard to Trichophyton species of A. benhamiae: Case 1: Kerion celsi by in a 6-year-old boy; Case 2: Deep trichophytia at the mons pubis in a 32-year-old man working in a pet shop and his 27-year-old female partner; Case 3: Tinea manuum in a 7-year-old girl; Case 4: Tinea corporis in an 8‑year-old girl. PMID:27380384

  2. Use of modified blood agar plate for identification of pathogenic campylobacter species at Mymensingh Medical College .

    PubMed

    Sarkar, S R; Hossain, M A; Pual, S K; Mahmud, M C; Ray, N C; Haque, N

    2014-10-01

    This cross sectional study was carried out from July 2011 to June 2012 in the Department of Microbiology, Mymensingh Medical College to diagnose etiology of diarrhea caused by Campylobacter species. A total of 200 clinically diagnosed diarrheal pediatric patients were included in this study. Among the 200 stool specimens evaluated, 23(11.5%) samples were positive for Campylobacter species, isolation rate was 15(65.2%) in upto 1 year age group and 08(34.7%) in more than 1 year age group. Among 23 positive cases, 20(86.95%) were C. jejuni and 03(13.05%) were C. coli. The prevalence of Campylobacter infection found in the present study was higher below 1 year age group and was very much close to other countries of this Sub continent.

  3. Modulation of Stat-1 in Human Macrophages Infected with Different Species of Intracellular Pathogenic Bacteria

    PubMed Central

    Dominici, Sabrina; Rinaldi, Laura; Cangiano, Alfonsina Mariarosaria; Brandi, Giorgio; Magnani, Mauro

    2016-01-01

    The infection of human macrophages by pathogenic bacteria induces different signaling pathways depending on the type of cellular receptors involved in the microorganism entry and on their mechanism(s) of survival and replication in the host cell. It was reported that Stat proteins play an important role in this process. In the present study, we investigate the changes in Stat-1 activation (phosphorylation in p-tyr701) after uptake of two Gram-positive (Listeria monocytogenes and Staphylococcus aureus) and two Gram-negative bacteria (Salmonella typhimurium and Legionella pneumophila) characterized by their varying abilities to enter, survive, and replicate in human macrophages. Comparing the results obtained with Gram-negative and Gram-positive bacteria, Stat-1 activation in macrophages does not seem to be related to LPS content. The p-tyr701Stat-1 expression levels were found to be independent of the internalized bacterial number and IFN-γ release. On the contrary, Jak/Stat-1 pathway activation only occurs when an active infection has been established in the host macrophage, and it is plausible that the differences in the expression levels of p-tyr701Stat-1 could be due to different survival mechanisms or to differences in bacteria life cycles within macrophages. PMID:27437406

  4. Extracellular vesicles from Paracoccidioides pathogenic species transport polysaccharide and expose ligands for DC-SIGN receptors

    PubMed Central

    da Silva, Roberta Peres; Heiss, Christian; Black, Ian; Azadi, Parastoo; Gerlach, Jared Q.; Travassos, Luiz R.; Joshi, Lokesh; Kilcoyne, Michelle; Puccia, Rosana

    2015-01-01

    Extracellular vesicles (EVs) mediate non-conventional transport of molecules across the fungal cell wall. We aimed at describing the carbohydrate composition and surface carbohydrate epitopes of EVs isolated from the pathogenic fungi Paracoccidioides brasiliensis and P. lutzii using standard procedures. Total EV carbohydrates were ethanol-precipitated from preparations depleted of lipids and proteins, then analyzed by chemical degradation, gas chromatography-mass spectrometry, nuclear magnetic resonance and size-exclusion chromatography. EV glycosyl residues of Glc, Man, and Gal comprised most probably two major components: a high molecular mass 4,6-α-glucan and a galactofuranosylmannan, possibly an oligomer, bearing a 2-α-Manp main chain linked to β-Galf (1,3) and α-Manp (1,6) end units. The results also suggested the presence of small amounts of a (1→6)-Manp polymer, (1→3)-glucan and (1→6)-glucan. Glycan microarrays allowed identification of EV surface lectin(s), while plant lectin microarray profiling revealed terminal Man and GlcNAc residues exposed at the EVs surface. Mammalian lectin microarray profiling showed that DC-SIGN receptors recognized surface carbohydrate in Paracoccidioides EVs. Our results suggest that oligosaccharides, cytoplasmic storage, and cell wall polysaccharides can be exported in fungal EVs, which also expose surface PAMPs and lectins. The role of these newly identified components in the interaction with the host remains to be unraveled. PMID:26387503

  5. Extracellular vesicles from Paracoccidioides pathogenic species transport polysaccharide and expose ligands for DC-SIGN receptors

    DOE PAGES

    da Silva, Roberta Peres; Heiss, Christian; Black, Ian; Azadi, Parastoo; Gerlach, Jared Q.; Travassos, Luiz R.; Joshi, Lokesh; Kilcoyne, Michelle; Puccia, Rosana

    2015-09-21

    Extracellular vesicles (EVs) mediate non-conventional transport of molecules across the fungal cell wall. We aimed at describing the carbohydrate composition and surface carbohydrate epitopes of EVs isolated from the pathogenic fungi Paracoccidioides brasiliensis and P. lutzii using standard procedures. Total EV carbohydrates were ethanol-precipitated from preparations depleted of lipids and proteins, then analyzed by chemical degradation, gas chromatography-mass spectrometry, nuclear magnetic resonance and size-exclusion chromatography. EV glycosyl residues of Glc, Man, and Gal comprised most probably two major components: a high molecular mass 4,6-α-glucan and a galactofuranosylmannan, possibly an oligomer, bearing a 2-α-Manp main chain linked to β-Galf (1,3) andmore » α-Manp (1,6) end units. The results also suggested the presence of small amounts of a (1→6)- Manp polymer, (1→3)-glucan and (1→6)-glucan. Glycan microarrays allowed identification of EV surface lectin(s), while plant lectin microarray profiling revealed terminal Man and GlcNAc residues exposed at the EVs surface. Mammalian lectin microarray profiling showed that DC-SIGN receptors recognized surface carbohydrate in Paracoccidioides EVs. Our results suggest that oligosaccharides, cytoplasmic storage, and cell wall polysaccharides can be exported in fungal EVs, which also expose surface PAMPs and lectins. As a result, the role of these newly identified components in the interaction with the host remains to be unraveled.« less

  6. Modulation of Stat-1 in Human Macrophages Infected with Different Species of Intracellular Pathogenic Bacteria.

    PubMed

    Schiavano, Giuditta Fiorella; Dominici, Sabrina; Rinaldi, Laura; Cangiano, Alfonsina Mariarosaria; Brandi, Giorgio; Magnani, Mauro

    2016-01-01

    The infection of human macrophages by pathogenic bacteria induces different signaling pathways depending on the type of cellular receptors involved in the microorganism entry and on their mechanism(s) of survival and replication in the host cell. It was reported that Stat proteins play an important role in this process. In the present study, we investigate the changes in Stat-1 activation (phosphorylation in p-tyr701) after uptake of two Gram-positive (Listeria monocytogenes and Staphylococcus aureus) and two Gram-negative bacteria (Salmonella typhimurium and Legionella pneumophila) characterized by their varying abilities to enter, survive, and replicate in human macrophages. Comparing the results obtained with Gram-negative and Gram-positive bacteria, Stat-1 activation in macrophages does not seem to be related to LPS content. The p-tyr701Stat-1 expression levels were found to be independent of the internalized bacterial number and IFN-γ release. On the contrary, Jak/Stat-1 pathway activation only occurs when an active infection has been established in the host macrophage, and it is plausible that the differences in the expression levels of p-tyr701Stat-1 could be due to different survival mechanisms or to differences in bacteria life cycles within macrophages. PMID:27437406

  7. Experimental hematogenous candidiasis caused by Candida krusei and Candida albicans: species differences in pathogenicity.

    PubMed Central

    Anaissie, E; Hachem, R; K-Tin-U, C; Stephens, L C; Bodey, G P

    1993-01-01

    Hematogenous infections caused by Candida krusei have been noted with increasing frequency, particularly in cancer patients receiving prophylaxis with antifungal triazoles. Progress in understanding the pathogenesis of this emerging infection has been limited by the lack of an animal model. We developed a CF1 mouse intravenous inoculation model of candidiasis to evaluate the pathogenicity of C. krusei in normal and immunosuppressed mice and to compare it with that of Candida albicans. Several inocula (10(6) to 10(8) CFU per animal) of two clinical strains of C. krusei and three American Type Culture Collection strains of C. albicans were tested. Groups of 20 mice each were injected with a single intravenous dose of one inoculum. Animals randomized to receive C. krusei were immunosuppressed by intraperitoneal injection of cyclophosphamide or the combination of cyclophosphamide plus cortisone acetate or they did not receive immunosuppressive agents (normal mice). One hundred percent mortality was observed in normal mice injected with 10(6) CFU of C. albicans per mouse compared with no mortality in normal mice that received 10(8) CFU of C. krusei per mouse (P < 0.01). Resistance to C. krusei infection was markedly lowered by immunosuppression, particularly by the combination of cyclophosphamide plus cortisone acetate, with a significantly shorter survival and a higher organ fungal burden in immunosuppressed than in normal animals (P < 0.01). Tissue infection was documented by culture and histopathologic findings in all examined organs. Images PMID:8454330

  8. Molecular analysis and pathogenicity of the Cladophialophora carrionii complex, with the description of a novel species

    PubMed Central

    de Hoog, G.S.; Nishikaku, A.S.; Fernandez-Zeppenfeldt, G.; Padín-González, C.; Burger, E.; Badali, H.; Richard-Yegres, N.; van den Ende, A.H.G. Gerrits

    2007-01-01

    Cladophialophora carrionii is one of the four major etiologic agents of human chromoblastomycosis in semi-arid climates. This species was studied using sequence data of the internal transcribed spacer region of rDNA, the partial β-tubulin gene and an intron in the translation elongation factor 1-alpha gene, in addition to morphology. With all genes a clear bipartition was observed, which corresponded with minute differences in conidiophore morphology. A new species, C. yegresii, was introduced, which appeared to be, in contrast to C. carrionii, associated with living cactus plants. All strains from humans, and a few isolates from dead cactus debris, belonged to C. carrionii, for which a lectotype was designated. Artificial inoculation of cactus plants grown from seeds in the greenhouse showed that both fungi are able to persist in cactus tissue. When reaching the spines they produce cells that morphologically resemble the muriform cells known as the “invasive form” in chromoblastomycosis. The tested clinical strain of C. carrionii proved to be more virulent in cactus than the environmental strain of C. yegresii that originated from the same species of cactus, Stenocereus griseus. The muriform cell expressed in cactus spines can be regarded as the extremotolerant survival phase, and is likely to play an essential role in the natural life cycle of these organisms. PMID:18491001

  9. Wildly Growing Asparagus (Asparagus officinalis L.) Hosts Pathogenic Fusarium Species and Accumulates Their Mycotoxins.

    PubMed

    Stępień, Łukasz; Waśkiewicz, Agnieszka; Urbaniak, Monika

    2016-05-01

    Asparagus officinalis L. is an important crop in many European countries, likely infected by a number of Fusarium species. Most of them produce mycotoxins in plant tissues, thus affecting the physiology of the host plant. However, there is lack of information on Fusarium communities in wild asparagus, where they would definitely have considerable environmental significance. Therefore, the main scientific aim of this study was to identify the Fusarium species and quantify their typical mycotoxins present in wild asparagus plants collected at four time points of the season. Forty-four Fusarium strains of eight species--Fusarium acuminatum, Fusarium avenaceum, Fusarium culmorum, Fusarium equiseti, Fusarium oxysporum, Fusarium proliferatum, Fusarium sporotrichioides, and Fusarium tricinctum--were isolated from nine wild asparagus plants in 2013 season. It is the first report of F. sporotrichioides isolated from this particular host. Fumonisin B1 was the most abundant mycotoxin, and the highest concentrations of fumonisins B1-B3 and beauvericin were found in the spears collected in May. Moniliformin and enniatins were quantified at lower concentrations. Mycotoxins synthesized by individual strains obtained from infected asparagus tissues were assessed using in vitro cultures on sterile rice grain. Most of the F. sporotrichioides strains synthesized HT-2 toxin and F. equiseti strains were found to be effective zearalenone producers. PMID:26687343

  10. Contact between bird species of different lifespans can promote the emergence of highly pathogenic avian influenza strains

    PubMed Central

    Wikramaratna, Paul S.; Pybus, Oliver G.; Gupta, Sunetra

    2014-01-01

    Outbreaks of highly pathogenic strains of avian influenza viruses (AIVs) cause considerable economic losses to the poultry industry and also pose a threat to human life. The possibility that one of these strains will evolve to become transmissible between humans, sparking a major influenza pandemic, is a matter of great concern. Most studies so far have focused on assessing these odds from the perspective of the intrinsic mutability of AIV rather than the ecological constraints to invasion faced by the virus population. Here we present an alternative multihost model for the evolution of AIV in which the mode and tempo of mutation play a limited role, with the emergence of strains being determined instead principally by the prevailing profile of population-level immunity. We show that (i) many of the observed differences in influenza virus dynamics among species can be captured by our model by simply varying host lifespan and (ii) increased contact between species of different lifespans can promote the emergence of potentially more virulent strains that were hitherto suppressed in one of the species. PMID:24958867

  11. Loofah sponges as reservoirs and vehicles in the transmission of potentially pathogenic bacterial species to human skin.

    PubMed

    Bottone, E J; Perez, A A; Oeser, J L

    1994-02-01

    Loofah sponges are natural products used as exfoliative beauty aids. As a consequence of tracing a case of Pseudomonas aeruginosa folliculitis to a contaminated loofah sponge, we assessed the role of loofah sponges in supporting the growth of a wide variety of bacterial species. Our data show growth enhancement of sterile loofah fragments for numerous gram-negative (Pseudomonas, Xanthomonas, and Klebsiella) and gram-positive (Enterococcus and group B Streptococcus) species of human and environmental origin. Furthermore, hydrated new, unused loofah sponges undergo a shift in bacterial flora from sparse colonies of Bacillus spp. and Staphylococcus epidermidis to a predominantly gram-negative flora. The growth-promoting potential of loofah sponges (and other exfoliatives) can be further augmented by desquamated epithelial cells entrapped in the loofah fibrous matrix. Therefore, as loofah sponges (and other exfoliatives) can serve as a reservoir and a vehicle for the transmission of potentially pathogenic species to the human skin, we recommend their decontamination with hypochlorite (10%) bleach at regular intervals. PMID:8150959

  12. Revisiting the reference genomes of human pathogenic Cryptosporidium species: reannotation of C. parvum Iowa and a new C. hominis reference

    PubMed Central

    Isaza, Juan P.; Galván, Ana Luz; Polanco, Victor; Huang, Bernice; Matveyev, Andrey V.; Serrano, Myrna G.; Manque, Patricio; Buck, Gregory A.; Alzate, Juan F.

    2015-01-01

    Cryptosporidium parvum and C. hominis are the most relevant species of this genus for human health. Both cause a self-limiting diarrhea in immunocompetent individuals, but cause potentially life-threatening disease in the immunocompromised. Despite the importance of these pathogens, only one reference genome of each has been analyzed and published. These two reference genomes were sequenced using automated capillary sequencing; as of yet, no next generation sequencing technology has been applied to improve their assemblies and annotations. For C. hominis, the main challenge that prevents a larger number of genomes to be sequenced is its resistance to axenic culture. In the present study, we employed next generation technology to analyse the genomic DNA and RNA to generate a new reference genome sequence of a C. hominis strain isolated directly from human stool and a new genome annotation of the C. parvum Iowa reference genome. PMID:26549794

  13. Staphylococcal biofilm exopolysaccharide protects against Caenorhabditis elegans immune defenses.

    PubMed

    Begun, Jakob; Gaiani, Jessica M; Rohde, Holger; Mack, Dietrich; Calderwood, Stephen B; Ausubel, Frederick M; Sifri, Costi D

    2007-04-01

    Staphylococcus epidermidis and Staphylococcus aureus are leading causes of hospital-acquired infections that have become increasingly difficult to treat due to the prevalence of antibiotic resistance in these organisms. The ability of staphylococci to produce biofilm is an important virulence mechanism that allows bacteria both to adhere to living and artificial surfaces and to resist host immune factors and antibiotics. Here, we show that the icaADBC locus, which synthesizes the biofilm-associated polysaccharide intercellular adhesin (PIA) in staphylococci, is required for the formation of a lethal S. epidermidis infection in the intestine of the model nematode Caenorhabditis elegans. Susceptibility to S. epidermidis infection is influenced by mutation of the C. elegans PMK-1 p38 mitogen-activated protein (MAP) kinase or DAF-2 insulin-signaling pathways. Loss of PIA production abrogates nematocidal activity and leads to reduced bacterial accumulation in the C. elegans intestine, while overexpression of the icaADBC locus in S. aureus augments virulence towards nematodes. PIA-producing S. epidermidis has a significant survival advantage over ica-deficient S. epidermidis within the intestinal tract of wild-type C. elegans, but not in immunocompromised nematodes harboring a loss-of-function mutation in the p38 MAP kinase pathway gene sek-1. Moreover, sek-1 and pmk-1 mutants are equally sensitive to wild-type and icaADBC-deficient S. epidermidis. These results suggest that biofilm exopolysaccharide enhances virulence by playing an immunoprotective role during colonization of the C. elegans intestine. These studies demonstrate that C. elegans can serve as a simple animal model for studying host-pathogen interactions involving staphylococcal biofilm exopolysaccharide and suggest that the protective activity of biofilm matrix represents an ancient conserved function for resisting predation.

  14. Staphylococcal Enterotoxin O Exhibits Cell Cycle Modulating Activity

    PubMed Central

    Hodille, Elisabeth; Alekseeva, Ludmila; Berkova, Nadia; Serrier, Asma; Badiou, Cedric; Gilquin, Benoit; Brun, Virginie; Vandenesch, François; Terman, David S.; Lina, Gerard

    2016-01-01

    Maintenance of an intact epithelial barrier constitutes a pivotal defense mechanism against infections. Staphylococcus aureus is a versatile pathogen that produces multiple factors including exotoxins that promote tissue alterations. The aim of the present study is to investigate the cytopathic effect of staphylococcal exotoxins SEA, SEG, SEI, SElM, SElN and SElO on the cell cycle of various human cell lines. Among all tested exotoxins only SEIO inhibited the proliferation of a broad panel of human tumor cell lines in vitro. Evaluation of a LDH release and a DNA fragmentation of host cells exposed to SEIO revealed that the toxin does not induce necrosis or apoptosis. Analysis of the DNA content of tumor cells synchronized by serum starvation after exposure to SEIO showed G0/G1 cell cycle delay. The cell cycle modulating feature of SEIO was confirmed by the flow cytometry analysis of synchronized cells exposed to supernatants of isogenic S. aureus strains wherein only supernatant of the SElO producing strain induced G0/G1 phase delay. The results of yeast-two-hybrid analysis indicated that SEIO’s potential partner is cullin-3, involved in the transition from G1 to S phase. In conclusion, we provide evidence that SEIO inhibits cell proliferation without inducing cell death, by delaying host cell entry into the G0/G1 phase of the cell cycle. We speculate that this unique cell cycle modulating feature allows SEIO producing bacteria to gain advantage by arresting the cell cycle of target cells as part of a broader invasive strategy. PMID:27148168

  15. Mapping the Pathways to Staphylococcal Pathogenesis by Comparative Secretomics

    PubMed Central

    Sibbald, M. J. J. B.; Ziebandt, A. K.; Engelmann, S.; Hecker, M.; de Jong, A.; Harmsen, H. J. M.; Raangs, G. C.; Stokroos, I.; Arends, J. P.; Dubois, J. Y. F.; van Dijl, J. M.

    2006-01-01

    The gram-positive bacterium Staphylococcus aureus is a frequent component of the human microbial flora that can turn into a dangerous pathogen. As such, this organism is capable of infecting almost every tissue and organ system in the human body. It does so by actively exporting a variety of virulence factors to the cell surface and extracellular milieu. Upon reaching their respective destinations, these virulence factors have pivotal roles in the colonization and subversion of the human host. It is therefore of major importance to obtain a clear understanding of the protein transport pathways that are active in S. aureus. The present review aims to provide a state-of-the-art roadmap of staphylococcal secretomes, which include both protein transport pathways and the extracytoplasmic proteins of these organisms. Specifically, an overview is presented of the exported virulence factors, pathways for protein transport, signals for cellular protein retention or secretion, and the exoproteomes of different S. aureus isolates. The focus is on S. aureus, but comparisons with Staphylococcus epidermidis and other gram-positive bacteria, such as Bacillus subtilis, are included where appropriate. Importantly, the results of genomic and proteomic studies on S. aureus secretomes are integrated through a comparative “secretomics” approach, resulting in the first definition of the core and variant secretomes of this bacterium. While the core secretome seems to be largely employed for general housekeeping functions which are necessary to thrive in particular niches provided by the human host, the variant secretome seems to contain the “gadgets” that S. aureus needs to conquer these well-protected niches. PMID:16959968

  16. Evidence of land-sea transfer of the zoonotic pathogen Campylobacter to a wildlife marine sentinel species.

    PubMed

    Baily, Johanna L; Méric, Guillaume; Bayliss, Sion; Foster, Geoffrey; Moss, Simon E; Watson, Eleanor; Pascoe, Ben; Mikhail, Jane; Pizzi, Romain; Goldstone, Robert J; Smith, David G E; Willoughby, Kim; Hall, Ailsa J; Sheppard, Samuel K; Dagleish, Mark P

    2015-01-01

    Environmental pollution often accompanies the expansion and urbanization of human populations where sewage and wastewaters commonly have an impact on the marine environments. Here, we explored the potential for faecal bacterial pathogens, of anthropic origin, to spread to marine wildlife in coastal areas. The common zoonotic bacterium Campylobacter was isolated from grey seals (Halichoerus grypus), an important sentinel species for environmental pollution, and compared to isolates from wild birds, agricultural sources and clinical samples to characterize possible transmission routes. Campylobacter jejuni was present in half of all grey seal pups sampled (24/50 dead and 46/90 live pups) in the breeding colony on the Isle of May (Scotland), where it was frequently associated with histological evidence of disease. Returning yearling animals (19/19) were negative for C. jejuni suggesting clearance of infection while away from the localized colony infection source. The genomes of 90 isolates from seals were sequenced and characterized using a whole-genome multilocus sequence typing (MLST) approach and compared to 192 published genomes from multiple sources using population genetic approaches and a probabilistic genetic attribution model to infer the source of infection from MLST data. The strong genotype-host association has enabled the application of source attribution models in epidemiological studies of human campylobacteriosis, and here assignment analyses consistently grouped seal isolates with those from human clinical samples. These findings are consistent with either a common infection source or direct transmission of human campylobacter to grey seals, raising concerns about the spread of human pathogens to wildlife marine sentinel species in coastal areas. PMID:25401947

  17. Species-specific activation of Cu/Zn SOD by its CCS copper chaperone in the pathogenic yeast Candida albicans.

    PubMed

    Gleason, Julie E; Li, Cissy X; Odeh, Hana M; Culotta, Valeria C

    2014-06-01

    Candida albicans is a pathogenic yeast of important public health relevance. Virulence of C. albicans requires a copper and zinc containing superoxide dismutase (SOD1), but the biology of C. albicans SOD1 is poorly understood. To this end, C. albicans SOD1 activation was examined in baker's yeast (Saccharomyces cerevisiae), a eukaryotic expression system that has proven fruitful for the study of SOD1 enzymes from invertebrates, plants, and mammals. In spite of the 80% similarity between S. cerevisiae and C. albicans SOD1 molecules, C. albicans SOD1 is not active in S. cerevisiae. The SOD1 appears incapable of productive interactions with the copper chaperone for SOD1 (CCS1) of S. cerevisiae. C. albicans SOD1 contains a proline at position 144 predicted to dictate dependence on CCS1. By mutation of this proline, C. albicans SOD1 gained activity in S. cerevisiae, and this activity was independent of CCS1. We identified a putative CCS1 gene in C. albicans and created heterozygous and homozygous gene deletions at this locus. Loss of CCS1 resulted in loss of SOD1 activity, consistent with its role as a copper chaperone. C. albicans CCS1 also restored activity to C. albicans SOD1 expressed in S. cerevisiae. C. albicans CCS1 is well adapted for activating its partner SOD1 from C. albicans, but not SOD1 from S. cerevisiae. In spite of the high degree of homology between the SOD1 and CCS1 molecules in these two fungal species, there exists a species-specific barrier in CCS-SOD interactions which may reflect the vastly different lifestyles of the pathogenic versus the noninfectious yeast.

  18. Effects of twenty-five compounds on four species of aquatic fungi (Saprolegniales) pathogenic to fish

    USGS Publications Warehouse

    Bailey, T.A.

    1984-01-01

    Four species of aquatic fungi (Achlya flagellata, A. racemosa, Saprolegnia hypogyna, and S. megasperma) were exposed to 25 chemicals representing seven classes of compounds for 15 and 60 min, in an effort to identify potential fungicidal agents for use in fish culture. The antifungal activity of each chemical was compared with that of malachite green, a reference compound with known fungicidal properties but not registered for fishery use. Six compounds which inhibited fungal growth on artificial media at concentrations of < 100 mg/l (listed in order of decreasing antifungal activity) were the cationics Du-terA? and copper oxychloride sulfate, the amine LesanA?, the amide BAS-389-O1F and the cationics CuprimyxinA? and RoccalA? II. Certain chemicals from these classes of compounds may have promise as aquatic fungicides.

  19. Effect of cinnamomum zeylanicum blume essential oil on the growth and morphogenesis of some potentially pathogenic Aspergillus species.

    PubMed

    Carmo, Egberto Santos; de Oliveira Lima, Edeltrudes; de Souza, Evandro Leite; de Sousa, Frederico Barbosa

    2008-01-01

    Cinnamomum zeylanicum Blume is known for a wide range of medicinal properties. This study aimed to assess the interference of C. zeylanicum essential oil on the growth and morphogenesis of some potentially pathogenic Aspergillus species. The essential oil presented strong antifungal effect causing the growth inhibition of the assayed strains and development of large growth inhibition zones. MIC50 and MIC90 values were 40 and 80 μL/mL, respectively. 80, 40 and 20 μL/mL of the oil strongly inhibited the radial mycelial growth of A. niger, A. flavus and A. fumigatus along 14 days. 80 and 40 μL/mL of the oil caused a 100% inhibition of the fungal spore germination. Main morphological changes observed under light microscopy provided by the essential oil in the fungal strains were decreased conidiation, leakage of cytoplasm, loss of pigmentation and disrupted cell structure indicating fungal wall degeneration. It is concluded that C. zeylanicum essential oil could be known as potential antifungal compound, particularly, to protect against the growth of Aspergillus species.

  20. An alternative to killing? Treatment of reservoir hosts to control a vector and pathogen in a susceptible species.

    PubMed

    Porter, R; Norman, R A; Gilbert, L

    2013-02-01

    Parasite-mediated apparent competition occurs when one species affects another through the action of a shared parasite. One way of controlling the parasite in the more susceptible host is to manage the reservoir host. Culling can cause issues in terms of ethics and biodiversity impacts, therefore we ask: can treating, as compared to culling, a wildlife host protect a target species from the shared parasite? We used Susceptible Infected Recovered (SIR) models parameterized for the tick-borne louping ill virus (LIV) system. Deer are the key hosts of the vector (Ixodes ricinus) that transmits LIV to red grouse Lagopus lagopus scoticus, causing high mortality. The model was run under scenarios of varying acaricide efficacy and deer densities. The model predicted that treating deer can increase grouse density through controlling ticks and LIV, if acaricide efficacies are high and deer densities low. Comparing deer treated with 70% acaricide efficacy with a 70% cull rate suggested that treatment may be more effective than culling if initial deer densities are high. Our results will help inform tick control policies, optimize the targeting of control methods and identify conditions where host management is most likely to succeed. Our approach is applicable to other host-vector-pathogen systems. PMID:22939093

  1. Effect of cinnamomum zeylanicum blume essential oil on the growth and morphogenesis of some potentially pathogenic Aspergillus species

    PubMed Central

    Carmo, Egberto Santos; de Oliveira Lima, Edeltrudes; de Souza, Evandro Leite; de Sousa, Frederico Barbosa

    2008-01-01

    Cinnamomum zeylanicum Blume is known for a wide range of medicinal properties. This study aimed to assess the interference of C. zeylanicum essential oil on the growth and morphogenesis of some potentially pathogenic Aspergillus species. The essential oil presented strong antifungal effect causing the growth inhibition of the assayed strains and development of large growth inhibition zones. MIC50 and MIC90 values were 40 and 80 μL/mL, respectively. 80, 40 and 20 μL/mL of the oil strongly inhibited the radial mycelial growth of A. niger, A. flavus and A. fumigatus along 14 days. 80 and 40 μL/mL of the oil caused a 100% inhibition of the fungal spore germination. Main morphological changes observed under light microscopy provided by the essential oil in the fungal strains were decreased conidiation, leakage of cytoplasm, loss of pigmentation and disrupted cell structure indicating fungal wall degeneration. It is concluded that C. zeylanicum essential oil could be known as potential antifungal compound, particularly, to protect against the growth of Aspergillus species. PMID:24031186

  2. Characterization of a New Pathogenic Acanthamoeba Species, A. byersi n. sp., Isolated from a Human with Fatal Amoebic Encephalitis

    PubMed Central

    Qvarnstrom, Yvonne; Nerad, Thomas A.; Visvesvara, Govinda S.

    2015-01-01

    Acanthamoeba spp. are free-living amoebae that are ubiquitous in natural environments. They can cause cutaneous, nasopharyngeal and disseminated infection, leading to granulomatous amebic encephalitis (GAE) in immunocompromised individuals. In addition, they can cause amoebic keratitis in contact lens wearers. Acanthamoeba GAE is almost always fatal because of difficulty and delay in diagnosis and lack of optimal antimicrobial therapy. Here we report the description of an unusual strain isolated from skin and brain of a GAE patient. The amoebae displayed large trophozoites and star-shaped cysts, characteristics for acanthamoebas belonging to morphology Group 1. However, its unique morphology and growth characteristics differentiated this new strain from other Group 1 species. DNA sequence analysis, secondary structure prediction and phylogenetic analysis of the 18S rRNA gene confirmed that this new strain belonged to Group 1 but that it was distinct from the other sequence types within that group. Thus, we hereby propose the establishment of a new species, Acanthamoeba byersi n. sp. as well as a new sequence type, T18, for this new strain. To our knowledge, this is the first report of a Group 1 Acanthamoeba that is indisputably pathogenic in humans. PMID:23879685

  3. River networks as ecological corridors for species, populations and pathogens of water-borne disease (Invited)

    NASA Astrophysics Data System (ADS)

    Rinaldo, A.; Bertuzzo, E.; Mari, L.; Suweis, S.; Ceola, S.; Carrara, F.; Rodriguez-Iturbe, I.

    2010-12-01

    Recent works at the interface of hydrology, geomorphology and ecology under an integrated framework of analysis will be reviewed with a view to a general theory for reactive transport on networks. A number of related topics will be reviewed, linked by the characters of stochastic transport, and the networked environmental matrix (including biodiversity of freshwater fish in river networks and vegetation along riparian systems, how river networks affected historic spreading of human populations, and how they influence the spreading of water-borne disease). The unique, coherent ecohydrological thread and similar mathematical methods will be exposed. Metacommunity and individual-based models will be described in the contexts of hydrochory, population and species migrations, and the spreading of infections of water-borne disease along the ecological corridors generated by the river basin. A general effect is shown to emerge on the effects of dendritic geometries on the ecological processes and dynamics operating on river basins. Insights provided by such a theory will lend themselves to issues of practical importance such as integration of riparian systems into large-scale resource management, spatial strategies to minimize loss of freshwater biodiversity, and effective prevention/vaccination campaigns against water-borne diseases.

  4. An investigation and evaluation on species and characteristics of pathogenic microorganisms in Chinese local hospital settings.

    PubMed

    Chen, Liang; Lü, Xiaoli; Cao, Weiping; Zhang, Chunxia; Xu, Rongfa; Meng, Xu; Chen, Keping

    2015-12-01

    There are currently great concerns about the level of bacterial contamination in hospitals, as well as resistance to antimicrobial agents. The species and characteristics of microbes in Chinese hospitals are closely related to healthcare safety and the prevention and control of infections. However, data on the exposure of patients to microbes in Chinese hospitals are limited. The present study investigated the genera of microorganisms in Chinese hospitals. We evaluated their characteristics, such as antibiotic susceptibility, tolerance to disinfectants, and toxicity, using silkworms (Bombyx mori) as an animal model. Twenty-six distinct bacterial strains were isolated, and their genera were determined by sequencing their 16S rDNA regions. Twenty-five strains were resistant to one or more antibiotics, and six strains were resistant to multiple antibiotics. The results of minimal inhibitory concentration testing showed that eight strains were resistant to a chlorine-containing disinfectant, and 12 strains were resistant to Povidone-iodine. Following the injection of bacterial cultures into the silkworm hemolymph, 15 strains killed all of the silkworms within 5 d. Additionally, bacterial strain 14 killed all of silkworms within 12 h with a median lethal dose of 4 × 10(4) colony-forming units/larva. This study provides useful information for healthcare safety in Chinese hospitals.

  5. Pulsed light for the inactivation of fungal biofilms of clinically important pathogenic Candida species.

    PubMed

    Garvey, Mary; Andrade Fernandes, Joao Paulo; Rowan, Neil

    2015-07-01

    Microorganisms are naturally found as biofilm communities more than planktonic free-floating cells; however, planktonic culture remains the current model for microbiological studies, such as disinfection techniques. The presence of fungal biofilms in the clinical setting has a negative impact on patient mortality, as Candida biofilms have proved to be resistant to biocides in numerous in vitro studies; however, there is limited information on the effect of pulsed light on sessile communities. Here we report on the use of pulsed UV light for the effective inactivation of clinically relevant Candida species. Fungal biofilms were grown by use of a CDC reactor on clinically relevant surfaces. Following a maximal 72 h formation period, the densely populated biofilms were exposed to pulsed light at varying fluences to determine biofilm sensitivity to pulsed-light inactivation. The results were then compared to planktonic cell inactivation. High levels of inactivation of C. albicans and C. parapsilosis biofilms were achieved with pulsed light for both 48 and 72 h biofilm structures. The findings suggest that pulsed light has the potential to provide a means of surface decontamination, subsequently reducing the risk of infection to patients. The research described herein deals with an important aspect of disease prevention and public health.

  6. Macroscopic amyloid fiber formation by staphylococcal biofilm associated SuhB protein.

    PubMed

    Dutta, Anirudha; Bhattacharyya, Sudipta; Kundu, Anirban; Dutta, Debabrata; Das, Amit Kumar

    2016-10-01

    Staphylococcus aureus is a commensal and opportunistic pathogen that causes lethal infections. Biofilm forming ability of S. aureus enhances its virulence since biofilm provides the bacteria protective shield against antibiotics and host immunity. Polysaccharide independent biofilm formation by several virulent S. aureus strains have been identified recently, where protein components substitute polysaccharide intercellular adhesin (PIA) involved in bacterial cell attachment. The suhB gene has been reported to be essential in staphylococcal PIA-independent biofilm formation. Overexpression of staphylococcal SuhB (SasuhB) in E. coli produces extracellular macroscopic fibers made of recombinant SaSuhB protein. The amyloidic nature of the fiber is evaluated by high resolution electron microscopy, X-ray fiber diffraction and amyloid specific dyes, such as Congo red and thioflavin-T binding assay. The fibers appear to be sticky in nature and bind a large number of bacterial cells. The results suggest the possible role of SaSuhB-fibers as a structural component as well as an adhesin in biofilm matrix. PMID:27497060

  7. Contamination of beef products with staphylococcal classical enterotoxins in Egypt and Saudi Arabia

    PubMed Central

    Shawish, Reyad R.; Al-Humam, Naser A.

    2016-01-01

    Food-borne pathogens are of high concern for public health and food safety. Staphylococcus aureus food poisoning is one of the most economically devastating types of food poisoning globally. The purpose of this study was to detect staphylococcal classical enterotoxins (SEs) in processed beef from Kingdom of Saudi Arabia (KSA) and Egypt. In the present investigation a total of 250 random processed meat samples (50 each of minced meat, beef burger, beef sausage, beef kofta and beef luncheon) were collected from different super markets in the study area. Using conventional cultural methods, samples were cultured for isolation and identification of S. aureus. Multiplex PCR was used to detect SEs of the classical type SEA, SEB, SEC and SED from isolates. The percentage presence of S. aureus in minced meat, beef burger, beef sausage, beef kofta and beef luncheon was 38%, 22%, 30%, 32% and 12%, respectively. Multiplex PCR indicated that all examined samples contain different types of classical staphylococcal enterotoxins and only minced meat samples contained all four types of toxins. Multiplex PCR is efficient in detection of SEs from food and may be used in tracing of toxins to promote food hygiene. Implications of contamination of processed meat to food hygiene in the study area are highlighted. PMID:27088066

  8. Staphylococcus aureus and Staphylococcal Food-Borne Disease: An Ongoing Challenge in Public Health

    PubMed Central

    Smith, Tara C.

    2014-01-01

    Staphylococcal food-borne disease (SFD) is one of the most common food-borne diseases worldwide resulting from the contamination of food by preformed S. aureus enterotoxins. It is one of the most common causes of reported food-borne diseases in the United States. Although several Staphylococcal enterotoxins (SEs) have been identified, SEA, a highly heat-stable SE, is the most common cause of SFD worldwide. Outbreak investigations have found that improper food handling practices in the retail industry account for the majority of SFD outbreaks. However, several studies have documented prevalence of S. aureus in many food products including raw retail meat indicating that consumers are at potential risk of S. aureus colonization and subsequent infection. Presence of pathogens in food products imposes potential hazard for consumers and causes grave economic loss and loss in human productivity via food-borne disease. Symptoms of SFD include nausea, vomiting, and abdominal cramps with or without diarrhea. Preventive measures include safe food handling and processing practice, maintaining cold chain, adequate cleaning and disinfection of equipment, prevention of cross-contamination in home and kitchen, and prevention of contamination from farm to fork. This paper provides a brief overview of SFD, contributing factors, risk that it imposes to the consumers, current research gaps, and preventive measures. PMID:24804250

  9. Interferon-γ Protects from Staphylococcal Alpha Toxin-Induced Keratinocyte Death through Apolipoprotein L1.

    PubMed

    Brauweiler, Anne M; Goleva, Elena; Leung, Donald Y M

    2016-03-01

    Staphylococcus aureus is a bacterial pathogen that frequently infects the skin, causing lesions and cell destruction through its primary virulence factor, alpha toxin. Here we show that interferon gamma (IFN-?) protects human keratinocytes from cell death induced by staphylococcal alpha toxin. We find that IFN-? prevents alpha toxin binding and reduces expression of the alpha toxin receptor, a disintegrin and metalloproteinase 10 (ADAM10). We determine that the mechanism for IFN-?-mediated resistance to alpha toxin involves the induction of autophagy, a process of cellular adaptation to sublethal damage. We find that IFN-? potently stimulates activation of the primary autophagy effector, light chain 3 (LC3). This process is dependent on upregulation of apolipoprotein L1. Depletion of apolipoprotein L1 by small interfering RNA significantly increases alpha toxin-induced lethality and inhibits activation of light chain 3. We conclude that IFN-? plays a significant role in protecting human keratinocytes from the lethal effects of staphylococcal alpha toxin through apolipoprotein L1-induced autophagy.

  10. Contamination of beef products with staphylococcal classical enterotoxins in Egypt and Saudi Arabia.

    PubMed

    Shawish, Reyad R; Al-Humam, Naser A

    2016-01-01

    Food-borne pathogens are of high concern for public health and food safety. Staphylococcus aureus food poisoning is one of the most economically devastating types of food poisoning globally. The purpose of this study was to detect staphylococcal classical enterotoxins (SEs) in processed beef from Kingdom of Saudi Arabia (KSA) and Egypt. In the present investigation a total of 250 random processed meat samples (50 each of minced meat, beef burger, beef sausage, beef kofta and beef luncheon) were collected from different super markets in the study area. Using conventional cultural methods, samples were cultured for isolation and identification of S. aureus. Multiplex PCR was used to detect SEs of the classical type SEA, SEB, SEC and SED from isolates. The percentage presence of S. aureus in minced meat, beef burger, beef sausage, beef kofta and beef luncheon was 38%, 22%, 30%, 32% and 12%, respectively. Multiplex PCR indicated that all examined samples contain different types of classical staphylococcal enterotoxins and only minced meat samples contained all four types of toxins. Multiplex PCR is efficient in detection of SEs from food and may be used in tracing of toxins to promote food hygiene. Implications of contamination of processed meat to food hygiene in the study area are highlighted. PMID:27088066

  11. Effect of species, breed and route of virus inoculation on the pathogenicity of H5N1 highly pathogenic influenza (HPAI) viruses in domestic ducks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    H5N1 highly pathogenic avian influenza (HPAI) viruses continue to be a threat to poultry in many regions of the world. Domestic ducks have been recognized as one of the primary factors in the spread of H5N1 HPAI. To improve the control of this disease it’s necessary to better understand the pathog...

  12. Crystal structure of the superantigen staphylococcal enterotoxin type A.

    PubMed Central

    Schad, E M; Zaitseva, I; Zaitsev, V N; Dohlsten, M; Kalland, T; Schlievert, P M; Ohlendorf, D H; Svensson, L A

    1995-01-01

    Staphylococcal enterotoxins are prototype superantigens characterized by their ability to bind to major histocompatibility complex (MHC) class II molecules and subsequently activate a large fraction of T-lymphocytes. The crystal structure of staphylococcal enterotoxin type A (SEA), a 27 kDa monomeric protein, was determined to 1.9 A resolution with an R-factor of 19.9% by multiple isomorphous replacement. SEA is a two domain protein composed of a beta-barrel and a beta-grasp motif demonstrating the same general structure as staphylococcal enterotoxins SEB and TSST-1. Unique for SEA, however, is a Zn2+ coordination site involved in MHC class II binding. Four amino acids including Ser1, His187, His225 and Asp227 were found to be involved in direct coordination of the metal ion. SEA is the first Zn2+ binding enterotoxin that has been structurally determined. Images PMID:7628431

  13. Production of staphylococcal enterotoxin A in cream-filled cake.

    PubMed

    Anunciaçao, L L; Linardi, W R; do Carmo, L S; Bergdoll, M S

    1995-07-01

    Cakes were baked with normal ingredients and filled with cream, inoculated with different size enterotoxigenic-staphylococcal inocula. Samples of the cakes were incubated at room temperature and put in the refrigerator. Samples of cake and filling were taken at different times and analyzed for staphylococcal count and presence of enterotoxin. The smaller the inoculum, the longer the time required for sufficient growth (10(6)) to occur for production of detectable enterotoxin. Enterotoxin added to the cake dough before baking (210 degrees C, 45 min) did not survive the baking. The presence of enterotoxin in the contaminated cream filling indicated this as the cause of staphylococcal food poisoning from cream-filled cakes. Refrigeration of the cakes prevented the growth of the staphylococci.

  14. Pharmacokinetics of intravenous linezolid in cerebrospinal fluid and plasma in neurointensive care patients with staphylococcal ventriculitis associated with external ventricular drains.

    PubMed

    Beer, Ronny; Engelhardt, Klaus W; Pfausler, Bettina; Broessner, Gregor; Helbok, Raimund; Lackner, Peter; Brenneis, Christian; Kaehler, Stefan T; Georgopoulos, Apostolos; Schmutzhard, Erich

    2007-01-01

    The pharmacokinetic profile of linezolid in cerebrospinal fluid (CSF) in five neurointensive care patients with staphylococcal ventriculitis was studied. The mean area under concentration-time curve (+/- standard deviation) was 63 +/- 18.9 mg x h/liter, with a CSF-to-plasma ratio of 0.8 +/- 0.3. Times above MIC in CSF were 99.8% and 57.2% for pathogens with MICs of 2 mg/liter and 4 mg/liter, respectively. PMID:17043116

  15. Stress and strain in staphylococcal nuclease.

    PubMed Central

    Hodel, A.; Kautz, R. A.; Jacobs, M. D.; Fox, R. O.

    1993-01-01

    Protein molecules generally adopt a tertiary structure in which all backbone and side chain conformations are arranged in local energy minima; however, in several well-refined protein structures examples of locally strained geometries, such as cis peptide bonds, have been observed. Staphylococcal nuclease A contains a single cis peptide bond between residues Lys 116 and Pro 117 within a type VIa beta-turn. Alternative native folded forms of nuclease A have been detected by NMR spectroscopy and attributed to a mixture of cis and trans isomers at the Lys 116-Pro 117 peptide bond. Analyses of nuclease variants K116G and K116A by NMR spectroscopy and X-ray crystallography are reported herein. The structure of K116A is indistinguishable from that of nuclease A, including a cis 116-117 peptide bond (92% populated in solution). The overall fold of K116G is also indistinguishable from nuclease A except in the region of the substitution (residues 112-117), which contains a predominantly trans Gly 116-Pro 117 peptide bond (80% populated in solution). Both Lys and Ala would be prohibited from adopting the backbone conformation of Gly 116 due to steric clashes between the beta-carbon and the surrounding residues. One explanation for these results is that the position of the ends of the residue 112-117 loop only allow trans conformations where the local backbone interactions associated with the phi and psi torsion angles are strained. When the 116-117 peptide bond is cis, less strained backbone conformations are available. Thus the relaxation of the backbone strain intrinsic to the trans conformation compensates for the energetically unfavorable cis X-Pro peptide bond. With the removal of the side chain from residue 116 (K116G), the backbone strain of the trans conformation is reduced to the point that the conformation associated with the cis peptide bond is no longer favorable. PMID:8495201

  16. Regulatory organization of the staphylococcal sae locus.

    PubMed

    Adhikari, Rajan P; Novick, Richard P

    2008-03-01

    This paper describes an investigation of the complex internal regulatory circuitry of the staphylococcal sae locus and the impact of modifying this circuitry on the expression of external genes in the sae regulon. The sae locus contains four genes, the saeR and S two-component signalling module (TCS), and saeP and Q, two upstream genes of hitherto unknown function. It is expressed from two promoters, P(A)sae, which transcribes only the TCS, and P(C)sae, which transcribes the entire locus. A bursa aurealis (bursa) transposon insertion in saeP in a derivative of Staphylococcus aureus NCTC 8325 has a profound effect on sae function. It modifies the activity of the TCS, changing the expression of many genes in the sae regulon, even though transcription of the TCS (from P(A)sae) is not interrupted. Moreover, these effects are not due to disruption of saeP since an in-frame deletion in saeP has essentially no phenotype. The phenotype of S. aureus strain Newman is remarkably similar to that of the saeP : : bursa and this similarity is explained by an amino acid substitution in the Newman saeS gene that is predicted to modify profoundly the signalling function of the protein. This concurrence suggests that the saeP : : bursa insertion affects the signalling function of saeS, a suggestion that is supported by the ability of an saeQR clone, but not an saeR clone, to complement the effects of the saeP : : bursa insertion.

  17. Staphylococcal scalded skin syndrome: diagnosis and management.

    PubMed

    Patel, Girish K; Finlay, Andrew Y

    2003-01-01

    Staphylococcal scalded skin syndrome (SSSS) is a common disorder that is usually seen in infants and children and rarely seen in adults. SSSS usually presents with a prodrome of sore throat or conjunctivitis. Extremely tender flaccid bullae, which are Nikolsky sign-positive, develop within 48 hours and commonly affect the flexures; occasionally, large areas of the skin may be involved. The bullae enlarge and rupture easily to reveal a moist erythematous base, which gives rise to the scalded appearance. SSSS in adults is a rare disorder, though there are now over 50 documented cases. Usually SSSS occurs in predisposed individuals, but not all adults have an underlying illness. Whereas mortality in childhood SSSS is approximately 4%, the mortality rate in adults is reported to be greater than 60%. SSSS is caused by an infection with a particular strain of Staphylococcus aureus, which leads to blistering of the upper layer of the skin, by the release of a circulating exotoxin. It has recently been demonstrated that the exfoliative exotoxin responsible for SSSS leads to the cleavage of desmoglein 1 complex, an important desmosomal protein. The same toxins that are responsible for causing SSSS also cause bullous impetigo. There appears to be a relationship between the disease extent, the amount of toxin produced and whether the toxin is released locally or systemically. As a result there is likely to be a spectrum of disease and there are likely to be a number of milder cases of adult SSSS that go undiagnosed. Social improvements and hygiene have led to a dramatic fall in the number of cases of SSSS. Treatment is usually straightforward, when there is no coexistent morbidity and the presentation is mild, but can be demanding if the patient is particularly ill. SSSS is still associated with mortality, particularly when it occurs in adults. PMID:12627992

  18. Effect of different ecological conditions on secondary metabolite production and gene expression in two mycotoxigenic plant pathogen Fusarium species: F. verticillioides and F. equiseti

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The genus Fusarium includes many species that are plant pathogens and many produce harmful secondary metabolites including fumonisins and trichothecenes. These mycotoxins can cause disease in animals and have been associated with cancers and birth defects in humans. Many factors influence the produc...

  19. International outbreak of staphylococcal food poisoning caused by contaminated lasagne.

    PubMed Central

    Woolaway, M. C.; Bartlett, C. L.; Wieneke, A. A.; Gilbert, R. J.; Murrell, H. C.; Aureli, P.

    1986-01-01

    An outbreak of staphylococcal food poisoning in Europe caused by contaminated lasagne was detected and monitored by both national and international surveillance systems. The common source was a pasta-producing factory in Italy and high levels of Staphylococcus aureus were detected in packets of dried lasagne distributed in Luxembourg, the UK, France and Italy. Forty-seven cases were reported in the UK. Outbreaks of staphylococcal food poisoning attributed to mishandling during the food processing stage are uncommon and pasta as the food vehicle is rare. Prompt recognition of the outbreak and rapid identification of the food vehicle enabled most of the consignment to be withdrawn from the market. PMID:3950399

  20. Horse species symposium: a novel approach to monitoring pathogen progression during uterine and placental infection in the mare using bioluminescence imaging technology and lux-modified bacteria.

    PubMed

    Ryan, P L; Christiansen, D L; Hopper, R M; Walters, F K; Moulton, K; Curbelo, J; Greene, J M; Willard, S T

    2011-05-01

    Uterine and placental infections are the leading cause of abortion, stillbirth, and preterm delivery in the mare. Whereas uterine and placental infections in women have been studied extensively, a comprehensive examination of the pathogenic processes leading to this unsatisfactory pregnancy outcome in the mare has yet to be completed. Most information in the literature relating to late-term pregnancy loss in mares is based on retrospective studies of clinical cases submitted for necropsy. Here we report the development and application of a novel approach, whereby transgenically modified bacteria transformed with lux genes of Xenorhabdus luminescens or Photorhabdus luminescens origin and biophotonic imaging are utilized to better understand pathogen-induced preterm birth in late-term pregnant mares. This technology uses highly sensitive bioluminescence imaging camera systems to localize and monitor pathogen progression during tissue invasion by measuring the bioluminescent signatures emitted by the lux-modified pathogens. This method has an important advantage in that it allows for the potential tracking of pathogens in vivo in real time and over time, which was hitherto impossible. Although the application of this technology in domestic animals is in its infancy, investigators were successful in identifying the fetal lungs, sinuses, nares, urinary, and gastrointestinal systems as primary tissues for pathogen invasion after experimental infection of pregnant mares with lux-modified Escherichia coli. It is important that pathogens were not detected in other vital organs, such as the liver, brain, and cardiac system. Such precision in localizing sites of pathogen invasion provides potential application for this novel approach in the development of more targeted therapeutic interventions for pathogen-related diseases in the equine and other domestic species. PMID:21239661

  1. Reactive oxygen species-dependent necroptosis in Jurkat T cells induced by pathogenic free-living Naegleria fowleri.

    PubMed

    Song, K-J; Jang, Y S; Lee, Y A; Kim, K A; Lee, S K; Shin, M H

    2011-07-01

    Naegleria fowleri, a free-living amoeba, is the causative pathogen of primary amoebic meningoencephalitis in humans and experimental mice. N. fowleri is capable of destroying tissues and host cells through lytic necrosis. However, the mechanism by which N. fowleri induces host cell death is unknown. Electron microscopy indicated that incubation of Jurkat T cells with N. fowleri trophozoites induced necrotic morphology of the Jurkat T cells. N. fowleri also induced cytoskeletal protein cleavage, extensive poly (ADP-ribose) polymerase hydrolysis and lactate dehydrogenase (LDH) release. Although no activation of caspase-3 was observed in Jurkat T cells co-incubated with amoebae, intracellular reactive oxygen species (ROS) were strongly generated by NADPH oxidase (NOX). Pretreating cells with necroptosis inhibitor necrostatin-1 or NOX inhibitor diphenyleneiodonium chloride (DPI) strongly inhibited amoeba-induced ROS generation and Jurkat cell death, whereas pan-caspase inhibitor z-VAD-fmk did not. N. fowleri-derived secretory products (NfSP) strongly induced intracellular ROS generation and cell death. Necroptotic effects of NfSP were effectively inhibited by pretreating NfSP with proteinase K. Moreover, NfSP-induced LDH release and intracellular ROS accumulation were inhibited by pretreating Jurkat T cells with DPI or necrostatin-1. These results suggest that N. fowleri induces ROS-dependent necroptosis in Jurkat T cells. PMID:21535020

  2. Reactive oxygen species-dependent necroptosis in Jurkat T cells induced by pathogenic free-living Naegleria fowleri.

    PubMed

    Song, K-J; Jang, Y S; Lee, Y A; Kim, K A; Lee, S K; Shin, M H

    2011-07-01

    Naegleria fowleri, a free-living amoeba, is the causative pathogen of primary amoebic meningoencephalitis in humans and experimental mice. N. fowleri is capable of destroying tissues and host cells through lytic necrosis. However, the mechanism by which N. fowleri induces host cell death is unknown. Electron microscopy indicated that incubation of Jurkat T cells with N. fowleri trophozoites induced necrotic morphology of the Jurkat T cells. N. fowleri also induced cytoskeletal protein cleavage, extensive poly (ADP-ribose) polymerase hydrolysis and lactate dehydrogenase (LDH) release. Although no activation of caspase-3 was observed in Jurkat T cells co-incubated with amoebae, intracellular reactive oxygen species (ROS) were strongly generated by NADPH oxidase (NOX). Pretreating cells with necroptosis inhibitor necrostatin-1 or NOX inhibitor diphenyleneiodonium chloride (DPI) strongly inhibited amoeba-induced ROS generation and Jurkat cell death, whereas pan-caspase inhibitor z-VAD-fmk did not. N. fowleri-derived secretory products (NfSP) strongly induced intracellular ROS generation and cell death. Necroptotic effects of NfSP were effectively inhibited by pretreating NfSP with proteinase K. Moreover, NfSP-induced LDH release and intracellular ROS accumulation were inhibited by pretreating Jurkat T cells with DPI or necrostatin-1. These results suggest that N. fowleri induces ROS-dependent necroptosis in Jurkat T cells.

  3. Side effects of rodent control on non-target species: Rodenticides increase parasite and pathogen burden in great bustards.

    PubMed

    Lemus, J A; Bravo, C; García-Montijano, M; Palacín, C; Ponce, C; Magaña, M; Alonso, J C

    2011-10-15

    For many years anticoagulant rodenticides have been used in vole control campaigns, in spite of the proven risk of secondary poisoning of non-target predators and scavengers. In this paper we analyse for the first time great bustard exposure and intoxication by anticoagulant rodenticides in Spain, based on residues found in the livers of 71 bustard carcasses collected during 1991-2010. Ten individuals contained chlorophacinone and one flocoumafen. Chlorophacinone level was significantly correlated with the pathogen and parasite burden of intoxicated birds. Moreover, through the last 12 years the annual number of great bustards that present chlorophacinone in liver collected in our study areas was correlated with vole peaks at a nearby area, suggesting that the ingestion of rodenticide was proportional to the amounts spread in the fields. We conclude that rodenticide consumption is a regular event among great bustards when baited cereal is spread on fields, and that this may cause chronic weakening of intoxicated individuals, possibly affecting their survival. Future rodent control actions should consider these negative side effects on non target granivorous steppe and farmland species, particularly when they are globally threatened. PMID:21889190

  4. Targeted mutagenesis in pathogenic Leptospira species: disruption of the LigB gene does not affect virulence in animal models of leptospirosis.

    PubMed

    Croda, Julio; Figueira, Claudio Pereira; Wunder, Elsio A; Santos, Cleiton S; Reis, Mitermayer G; Ko, Albert I; Picardeau, Mathieu

    2008-12-01

    The pathogenic mechanisms of Leptospira interrogans, the causal agent of leptospirosis, remain largely unknown. This is mainly due to the lack of tools for genetically manipulating pathogenic Leptospira species. Thus, homologous recombination between introduced DNA and the corresponding chromosomal locus has never been demonstrated for this pathogen. Leptospiral immunoglobulin-like repeat (Lig) proteins were previously identified as putative Leptospira virulence factors. In this study, a ligB mutant was constructed by allelic exchange in L. interrogans; in this mutant a spectinomycin resistance (Spc(r)) gene replaced a portion of the ligB coding sequence. Gene disruption was confirmed by PCR, immunoblot analysis, and immunofluorescence studies. The ligB mutant did not show decrease virulence compared to the wild-type strain in the hamster model of leptospirosis. In addition, inoculation of rats with the ligB mutant induced persistent colonization of the kidneys. Finally, LigB was not required to mediate bacterial adherence to cultured cells. Taken together, our data provide the first evidence of site-directed homologous recombination in pathogenic Leptospira species. Furthermore, our data suggest that LigB does not play a major role in dissemination of the pathogen in the host and in the development of acute disease manifestations or persistent renal colonization. PMID:18809657

  5. Pathogenicity of two recent Western Mediterranean West Nile virus isolates in a wild bird species indigenous to Southern Europe: the red-legged partridge.

    PubMed

    Sotelo, Elena; Gutierrez-Guzmán, Ana Valeria; del Amo, Javier; Llorente, Francisco; El-Harrak, Mehdi; Pérez-Ramírez, Elisa; Blanco, Juan Manuel; Höfle, Ursula; Jiménez-Clavero, Miguel Angel

    2011-01-01

    West Nile virus (WNV) is an emerging zoonotic pathogen whose geographic spread and incidence in humans, horses and birds has increased significantly in recent years. WNV has long been considered a mild pathogen causing self-limiting outbreaks. This notion has changed as WNV is causing large epidemics with a high impact on human and animal health. This has been particularly noteworthy since its introduction into North America in 1999. There, native bird species have been shown to be highly susceptible to WNV infection and disease with high mortalities. For this reason, the effect of WNV infection in North American bird species has been thoroughly studied by means of experimental inoculations in controlled trials. To a lesser extent, European wild birds have been shown to be affected clinically by WNV infection. Yet experimental studies on European wild bird species are lacking. The red-legged partridge (Alectoris rufa) is a gallinaceous bird indigenous to the Iberian Peninsula, widely distributed in South Western Europe. It plays a key role in the Mediterranean ecosystem and constitutes an economically important game species. As such it is raised intensively in outdoor facilities. In this work, red-legged partridges were experimentally infected with two recent WNV isolates from the Western Mediterranean area: Morocco/2003 and Spain/2007. All inoculated birds became viremic and showed clinical disease, with mortality rates of 70% and 30%, respectively. These results show that Western Mediterranean WNV variants can be pathogenic for some European bird species, such as the red-legged partridge. PMID:21314967

  6. Pathogenicity of two recent Western Mediterranean West Nile virus isolates in a wild bird species indigenous to Southern Europe: the red-legged partridge

    PubMed Central

    2011-01-01

    West Nile virus (WNV) is an emerging zoonotic pathogen whose geographic spread and incidence in humans, horses and birds has increased significantly in recent years. WNV has long been considered a mild pathogen causing self-limiting outbreaks. This notion has changed as WNV is causing large epidemics with a high impact on human and animal health. This has been particularly noteworthy since its introduction into North America in 1999. There, native bird species have been shown to be highly susceptible to WNV infection and disease with high mortalities. For this reason, the effect of WNV infection in North American bird species has been thoroughly studied by means of experimental inoculations in controlled trials. To a lesser extent, European wild birds have been shown to be affected clinically by WNV infection. Yet experimental studies on European wild bird species are lacking. The red-legged partridge (Alectoris rufa) is a gallinaceous bird indigenous to the Iberian Peninsula, widely distributed in South Western Europe. It plays a key role in the Mediterranean ecosystem and constitutes an economically important game species. As such it is raised intensively in outdoor facilities. In this work, red-legged partridges were experimentally infected with two recent WNV isolates from the Western Mediterranean area: Morocco/2003 and Spain/2007. All inoculated birds became viremic and showed clinical disease, with mortality rates of 70% and 30%, respectively. These results show that Western Mediterranean WNV variants can be pathogenic for some European bird species, such as the red-legged partridge. PMID:21314967

  7. 21 CFR 866.2050 - Staphylococcal typing bacteriophage.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Staphylococcal typing bacteriophage. 866.2050 Section 866.2050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices §...

  8. 21 CFR 866.2050 - Staphylococcal typing bacteriophage.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Staphylococcal typing bacteriophage. 866.2050 Section 866.2050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices §...

  9. 21 CFR 866.2050 - Staphylococcal typing bacteriophage.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Staphylococcal typing bacteriophage. 866.2050 Section 866.2050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices §...

  10. 21 CFR 866.2050 - Staphylococcal typing bacteriophage.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Staphylococcal typing bacteriophage. 866.2050 Section 866.2050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices §...

  11. 21 CFR 866.2050 - Staphylococcal typing bacteriophage.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Staphylococcal typing bacteriophage. 866.2050 Section 866.2050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices §...

  12. Antifungal activity of a synthetic cationic peptide against the plant pathogens Colletotrichum graminicola and three Fusarium species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A small cationic peptide (JH8944) was tested for activity against a number of pathogens of agricultural crops. JH8944 inhibited conidium growth in most of the tested plant pathogens with a dose of 50 µg ml 1, although one isolate of Fusarium oxysporum was inhibited at 5 µg ml 1. Most conidia of Fusa...

  13. Multilocus genetic characterization of two ant vectors (Group II "Dirty 22" species) known to contaminate food and food products and spread foodborne pathogens.

    PubMed

    Sulaiman, Irshad M; Anderson, Mickey; Oi, David H; Simpson, Steven; Kerdahi, Khalil

    2012-08-01

    The U.S. Food and Drug Administration utilizes the presence of filth and extraneous materials as one of the criteria for implementing regulatory actions and assessing adulteration of food products of public health importance. Twenty-two prevalent pest species (also known as the ''Dirty 22'' species) have been considered by this agency as possible vehicles for the spread of foodborne diseases, and the presence of these species is considered an indicator of unsanitary conditions in food processing and storage facilities. In a previous study, we further categorized the Dirty 22 species into four groups: group I includes four cockroach species, group II includes two ant species, group III includes 12 fly species, and group IV includes four rodent species. Here, we describe the development of three nested PCR primer sets and multilocus genetic characterization by amplifying the small subunit rRNA, elongation factor 1-alpha, and wingless (WNT-1) genes of group II Dirty 22 ant species Monomorium pharaonis and Solenopsis molesta. These novel group II Dirty 22 species-specific nested PCR primer sets can be used when the specimens cannot be identified using conventional microscopic methods. These newly developed assays will provide correct identification of group II Dirty 22 ant species, and the information can be used in the control of foodborne pathogens.

  14. Screening non-coding RNAs in transcriptomes from neglected species using PORTRAIT: case study of the pathogenic fungus Paracoccidioides brasiliensis

    PubMed Central

    Arrial, Roberto T; Togawa, Roberto C; Brigido, Marcelo de M

    2009-01-01

    Background Transcriptome sequences provide a complement to structural genomic information and provide snapshots of an organism's transcriptional profile. Such sequences also represent an alternative method for characterizing neglected species that are not expected to undergo whole-genome sequencing. One difficulty for transcriptome sequencing of these organisms is the low quality of reads and incomplete coverage of transcripts, both of which compromise further bioinformatics analyses. Another complicating factor is the lack of known protein homologs, which frustrates searches against established protein databases. This lack of homologs may be caused by divergence from well-characterized and over-represented model organisms. Another explanation is that non-coding RNAs (ncRNAs) may be caught during sequencing. NcRNAs are RNA sequences that, unlike messenger RNAs, do not code for protein products and instead perform unique functions by folding into higher order structural conformations. There is ncRNA screening software available that is specific for transcriptome sequences, but their analyses are optimized for those transcriptomes that are well represented in protein databases, and also assume that input ESTs are full-length and high quality. Results We propose an algorithm called PORTRAIT, which is suitable for ncRNA analysis of transcriptomes from poorly characterized species. Sequences are translated by software that is resistant to sequencing errors, and the predicted putative proteins, along with their source transcripts, are evaluated for coding potential by a support vector machine (SVM). Either of two SVM models may be employed: if a putative protein is found, a protein-dependent SVM model is used; if it is not found, a protein-independent SVM model is used instead. Only ab initio features are extracted, so that no homology information is needed. We illustrate the use of PORTRAIT by predicting ncRNAs from the transcriptome of the pathogenic fungus

  15. Evolution of N-species Kimura/voter models towards criticality, a surrogate for general models of accidental pathogens

    NASA Astrophysics Data System (ADS)

    Ghaffari, Peyman; Stollenwerk, Nico

    2012-09-01

    In models for accidental pathogens, with the paradigmatic epidemiological system of bacterial meningitis, there was evolution towards states exhibiting critical fluctuations with power law behaviour observed [1]. This is a model with many possibly pathogenic strains essentially evolving independently to low pathogenicity. A first and previous study had shown that in the limit of vanishing pathogenicity there are critical fluctuations with power law distributions observed, already when only two strains interact [2]. This earlier version of a two strain model was very recently reinvestigated [3] and named as Stollenwerk-Jansen model (SJ). Muñoz et al. demonstrated that this two-strain model for accidental pathogens is in the universality class of the so-called voter model. Though this model clearly shows criticality, its control parameter, the pathogenicity, is not self-tuning towards criticality. However, the multi-strain version mentioned above [1] is well evolving towards criticality, as well as a spatially explicit version of this, shown in [4] p. 155. These models of multi-strain type including explicitly mutations of the pathogenicity can be called SJ-models of type II [5]. Since the original epidemiological model is of SIRYX-type, the evolution to zero pathogenicity is slow and perturbed by large population noise. In the present article we now show on the basis of the notion of the voter-model universality classes the evolution of n-voter models with mutaion towards criticality, now much less perturbed by population noise, hence demonstrating a clear mechanism of self-organized criticality in the sense of [6, 7]. The present results have wide implications for many diseases in which a large proportion of infections is asymptomatic, meaning that the system has already evolved towards an average low pathogenicity. This holds not only for the original paradigmatic case of bacterial meningitis, but was reecently also suggested for example for dengue fever (DENFREE

  16. Small heat-shock proteins, IbpAB, protect non-pathogenic Escherichia coli from killing by macrophage-derived reactive oxygen species.

    PubMed

    Goeser, Laura; Fan, Ting-Jia; Tchaptchet, Sandrine; Stasulli, Nikolas; Goldman, William E; Sartor, R Balfour; Hansen, Jonathan J

    2015-01-01

    Many intracellular bacterial pathogens possess virulence factors that prevent detection and killing by macrophages. However, similar virulence factors in non-pathogenic bacteria are less well-characterized and may contribute to the pathogenesis of chronic inflammatory conditions such as Crohn's disease. We hypothesize that the small heat shock proteins IbpAB, which have previously been shown to reduce oxidative damage to proteins in vitro and be upregulated in luminal non-pathogenic Escherichia strain NC101 during experimental colitis in vivo, protect commensal E. coli from killing by macrophage-derived reactive oxygen species (ROS). Using real-time PCR, we measured ibpAB expression in commensal E. coli NC101 within wild-type (wt) and ROS-deficient (gp91phox(-/-)) macrophages and in NC101 treated with the ROS generator paraquat. We also quantified survival of NC101 and isogenic mutants in wt and gp91phox(-/-) macrophages using gentamicin protection assays. Similar assays were performed using a pathogenic E. coli strain O157:H7. We show that non-pathogenic E. coli NC101inside macrophages upregulate ibpAB within 2 hrs of phagocytosis in a ROS-dependent manner and that ibpAB protect E. coli from killing by macrophage-derived ROS. Moreover, we demonstrate that ROS-induced ibpAB expression is mediated by the small E. coli regulatory RNA, oxyS. IbpAB are not upregulated in pathogenic E. coli O157:H7 and do not affect its survival within macrophages. Together, these findings indicate that ibpAB may be novel virulence factors for certain non-pathogenic E. coli strains. PMID:25798870

  17. Species-Specific Identification of a Wide Range of Clinically Relevant Fungal Pathogens by Use of Luminex xMAP Technology▿ †

    PubMed Central

    Landlinger, C.; Preuner, S.; Willinger, B.; Haberpursch, B.; Racil, Z.; Mayer, J.; Lion, T.

    2009-01-01

    In immunocompromised patients suffering from invasive fungal infection, rapid identification of the fungal species is a prerequisite for selection of the most appropriate antifungal treatment. We present an assay permitting reliable identification of a wide range of clinically relevant fungal pathogens based on the high-throughput Luminex microbead hybridization technology. The internal transcribed spacer (ITS2) region, which is highly variable among genomes of individual fungal species, was used to generate oligonucleotide hybridization probes for specific identification. The spectrum of pathogenic fungi covered by the assay includes the most commonly occurring species of the genera Aspergillus and Candida and a number of important emerging fungi, such as Cryptococcus, Fusarium, Trichosporon, Mucor, Rhizopus, Penicillium, Absidia, and Acremonium. Up to three different probes are employed for the detection of each fungal species. The redundancy in the design of the assay should ensure unambiguous fungus identification even in the presence of mutations in individual target regions. The current set of hybridization oligonucleotides includes 75 species- and genus-specific probes which had been carefully tested for specificity by repeated analysis of multiple reference strains. To provide adequate sensitivity for clinical application, the assay includes amplification of the ITS2 region by a seminested PCR approach prior to hybridization of the amplicons to the probe panel using the Luminex technology. A variety of fungal pathogens were successfully identified in clinical specimens that included peripheral blood, samples from biopsies of pulmonary infiltrations, and bronchotracheal secretions derived from patients with documented invasive fungal infections. Our observations demonstrate that the Luminex-based technology presented permits rapid and reliable identification of fungal species and may therefore be instrumental in routine clinical diagnostics. PMID:19244466

  18. Survey and competition assay data suggest species-specific difference in host/niche adaptation influence the distribution of Fusarium graminearum species complex pathogens in Brazil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Fusarium graminearum species complex (FGSC) comprises at least 16 toxigenic species of economic concern to cereal crops. In Brazil, six species of the FGSC have been identified, but their frequencies vary according to the host species. Although F. graminearum (Fgra) is dominant in wheat (>90%) a...

  19. Evaluation of three 5' exonuclease-based real-time polymerase chain reaction assays for detection of pathogenic Leptospira species in canine urine.

    PubMed

    Fink, Jamie M; Moore, George E; Landau, Ruth; Vemulapalli, Ramesh

    2015-03-01

    Leptospirosis is caused by several pathogenic Leptospira species, and is an important infectious disease of dogs. Early detection of infection is crucial for an effective antibiotic treatment of the disease. Though different polymerase chain reaction (PCR) assays have been developed for detection of pathogenic Leptospira spp., thorough evaluation of the performance of these assays using dog urine samples has not been carried out. In the current study, the performance of 3 real-time PCR (qPCR) assays was assessed, 1 targeting the 16S ribosomal RNA (rRNA) gene and the other 2 targeting the lipL32 gene, a gene for the LipL32 outer membrane protein. With DNA extracted from laboratory-cultured pathogenic Leptospira spp., all 3 qPCR assays showed 100% specificity and had identical lower limits of detection. Compared to a conventional, gel-based PCR assay, all 3 qPCR assays were 100-fold more sensitive. There was a 100% agreement in the results of the 3 assays when tested on urine samples collected aseptically from 30 dogs suspected for leptospirosis. However, when tested on 30 urine samples that were collected by the free-catch method, the 16S rRNA-based assay falsely detected 13.3% of the samples as positive for pathogenic Leptospira spp. Nucleotide sequence analysis of the amplified DNA fragments showed that the assay resulted in false positives because of unrelated bacteria. All urine samples collected from 100 apparently healthy dogs at a local animal shelter tested negative for pathogenic Leptospira spp. These results highlight the importance of sample-specific validation of PCR-based diagnostic assays and the application of appropriately validated assays for more reliable pathogen detection. PMID:25776541

  20. Enterotoxin B is the predominant toxin involved in staphylococcal scarlet fever in Taiwan.

    PubMed

    Wang, Chih-Chien; Lo, Wen-Tsung; Hsu, Chen-Fang; Chu, Mong-Ling

    2004-05-15

    This study retrospectively reviewed all pediatric cases of staphylococcal scarlet fever (SSF) that occurred during a 10-year period in a 1400-bed tertiary medical center in northern Taiwan. All 20 cases of SSF occurred in previously healthy individuals. Skin and soft-tissue infections predominated among children from whom Staphylococcus aureus was isolated. Polymerase chain reaction testing was used to detect known staphylococcal toxin genes, and of the isolates studied, most (18 [90%] of 20) contained only the staphylococcal enterotoxin B. One of the other strains was positive for staphylococcal enterotoxin A only, and the last strain was positive for both staphylococcal enterotoxin G and staphylococcal enterotoxin I. Pulsed-field gel electrophoresis identified a small cluster of isolates (6 [30%] of 20) that were genetically related, but these strains came from epidemiologically unrelated patients during a 3-year period.

  1. Serious Complications from Staphylococcal aureus in Atopic Dermatitis.

    PubMed

    Patel, Devika; Jahnke, Marla N

    2015-01-01

    Colonization with Staphylococcal aureus is markedly more frequent in individuals with atopic dermatitis (AD) than in unaffected individuals. Chronic scratching leads to worsening of an existing defect in the epidermal barrier, which can allow S. aureus invasion into the bloodstream and subsequent systemic infections. We report two unusual cases of systemic illness in individuals with AD. One developed infective endocarditis followed by a stroke and the other developed septic arthritis and osteomyelitis. We performed an extensive literature review of reported systemic complications caused by S. aureus in patients with AD. Although reports are rare, practitioners should be aware of these important, albeit unlikely, complications of staphylococcal superinfections in individuals with AD. PMID:26337792

  2. Pathogen intelligence.

    PubMed

    Steinert, Michael

    2014-01-01

    Different species inhabit different sensory worlds and thus have evolved diverse means of processing information, learning and memory. In the escalated arms race with host defense, each pathogenic bacterium not only has evolved its individual cellular sensing and behavior, but also collective sensing, interbacterial communication, distributed information processing, joint decision making, dissociative behavior, and the phenotypic and genotypic heterogeneity necessary for epidemiologic success. Moreover, pathogenic populations take advantage of dormancy strategies and rapid evolutionary speed, which allow them to save co-generated intelligent traits in a collective genomic memory. This review discusses how these mechanisms add further levels of complexity to bacterial pathogenicity and transmission, and how mining for these mechanisms could help to develop new anti-infective strategies. PMID:24551600

  3. Pathogen intelligence

    PubMed Central

    Steinert, Michael

    2014-01-01

    Different species inhabit different sensory worlds and thus have evolved diverse means of processing information, learning and memory. In the escalated arms race with host defense, each pathogenic bacterium not only has evolved its individual cellular sensing and behavior, but also collective sensing, interbacterial communication, distributed information processing, joint decision making, dissociative behavior, and the phenotypic and genotypic heterogeneity necessary for epidemiologic success. Moreover, pathogenic populations take advantage of dormancy strategies and rapid evolutionary speed, which allow them to save co-generated intelligent traits in a collective genomic memory. This review discusses how these mechanisms add further levels of complexity to bacterial pathogenicity and transmission, and how mining for these mechanisms could help to develop new anti-infective strategies. PMID:24551600

  4. Monkey Feeding Assay for Testing Emetic Activity of Staphylococcal Enterotoxin.

    PubMed

    Seo, Keun Seok

    2016-01-01

    Staphylococcal enterotoxins (SEs) are unique bacterial toxins that cause gastrointestinal toxicity as well as superantigenic activity. Since systemic administration of SEs induces superantigenic activity leading to toxic shock syndrome that may mimic enterotoxic activity of SEs such as vomiting and diarrhea, oral administration of SEs in the monkey feeding assay is considered as a standard method to evaluate emetic activity of SEs. This chapter summarizes and discusses practical considerations of the monkey feeding assay used in studies characterizing classical and newly identified SEs.

  5. Sequence Variability in Staphylococcal Enterotoxin Genes seb, sec, and sed

    PubMed Central

    Johler, Sophia; Sihto, Henna-Maria; Macori, Guerrino; Stephan, Roger

    2016-01-01

    Ingestion of staphylococcal enterotoxins preformed by Staphylococcus aureus in food leads to staphylococcal food poisoning, the most prevalent foodborne intoxication worldwide. There are five major staphylococcal enterotoxins: SEA, SEB, SEC, SED, and SEE. While variants of these toxins have been described and were linked to specific hosts or levels or enterotoxin production, data on sequence variation is still limited. In this study, we aim to extend the knowledge on promoter and gene variants of the major enterotoxins SEB, SEC, and SED. To this end, we determined seb, sec, and sed promoter and gene sequences of a well-characterized set of enterotoxigenic Staphylococcus aureus strains originating from foodborne outbreaks, human infections, human nasal colonization, rabbits, and cattle. New nucleotide sequence variants were detected for all three enterotoxins and a novel amino acid sequence variant of SED was detected in a strain associated with human nasal colonization. While the seb promoter and gene sequences exhibited a high degree of variability, the sec and sed promoter and gene were more conserved. Interestingly, a truncated variant of sed was detected in all tested sed harboring rabbit strains. The generated data represents a further step towards improved understanding of strain-specific differences in enterotoxin expression and host-specific variation in enterotoxin sequences. PMID:27258311

  6. Repurposing ebselen for treatment of multidrug-resistant staphylococcal infections

    PubMed Central

    Thangamani, Shankar; Younis, Waleed; Seleem, Mohamed N.

    2015-01-01

    Novel antimicrobials and new approaches to developing them are urgently needed. Repurposing already-approved drugs with well-characterized toxicology and pharmacology is a novel way to reduce the time, cost, and risk associated with antibiotic innovation. Ebselen, an organoselenium compound, is known to be clinically safe and has a well-known pharmacology profile. It has shown potent bactericidal activity against multidrug-resistant clinical isolates of staphylococcus aureus, including methicillin- and vancomycin-resistant S. aureus (MRSA and VRSA). We demonstrated that ebselen acts through inhibition of protein synthesis and subsequently inhibited toxin production in MRSA. Additionally, ebselen was remarkably active and significantly reduced established staphylococcal biofilms. The therapeutic efficacy of ebselen was evaluated in a mouse model of staphylococcal skin infections. Ebselen 1% and 2% significantly reduced the bacterial load and the levels of the pro-inflammatory cytokines tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1 beta (IL-1β), and monocyte chemo attractant protein-1 (MCP-1) in MRSA USA300 skin lesions. Furthermore, it acts synergistically with traditional antimicrobials. This study provides evidence that ebselen has great potential for topical treatment of MRSA skin infections and lays the foundation for further analysis and development of ebselen as a potential treatment for multidrug-resistant staphylococcal infections. PMID:26111644

  7. Sequence Variability in Staphylococcal Enterotoxin Genes seb, sec, and sed.

    PubMed

    Johler, Sophia; Sihto, Henna-Maria; Macori, Guerrino; Stephan, Roger

    2016-01-01

    Ingestion of staphylococcal enterotoxins preformed by Staphylococcus aureus in food leads to staphylococcal food poisoning, the most prevalent foodborne intoxication worldwide. There are five major staphylococcal enterotoxins: SEA, SEB, SEC, SED, and SEE. While variants of these toxins have been described and were linked to specific hosts or levels or enterotoxin production, data on sequence variation is still limited. In this study, we aim to extend the knowledge on promoter and gene variants of the major enterotoxins SEB, SEC, and SED. To this end, we determined seb, sec, and sed promoter and gene sequences of a well-characterized set of enterotoxigenic Staphylococcus aureus strains originating from foodborne outbreaks, human infections, human nasal colonization, rabbits, and cattle. New nucleotide sequence variants were detected for all three enterotoxins and a novel amino acid sequence variant of SED was detected in a strain associated with human nasal colonization. While the seb promoter and gene sequences exhibited a high degree of variability, the sec and sed promoter and gene were more conserved. Interestingly, a truncated variant of sed was detected in all tested sed harboring rabbit strains. The generated data represents a further step towards improved understanding of strain-specific differences in enterotoxin expression and host-specific variation in enterotoxin sequences.

  8. Varied pathogenicity of a Hong Kong-origin H5N1 avian influenza virus in four passerine species and budgerigars.

    PubMed

    Perkins, L E L; Swayne, D E

    2003-01-01

    This investigation assessed the ability of the zoonotic A/chicken/Hong Kong/220/97 (chicken/Hong Kong) (H5N1) highly pathogenic avian influenza virus to infect and cause disease in zebra finches (Taeniopygia guttata), house finches (Carpodacus mexicanus), house sparrows (Passer domesticus), European starlings (Sternus vulgaris), and budgerigars (Melopsittacus undulatus) after intranasal administration. Zebra finches were the most severely affected of the five species, demonstrating anorexia, depression, and 100% mortality within 5 days of inoculation. Gross lesions in this species were absent or only mild. But histologic lesions and the corresponding viral antigen were observed in multiple organs, especially in the nasal cavity, brain, pancreas, spleen, adrenal glands, and ovary. Significant morbidity and mortality also were observed in both house finches and budgerigars. Affected birds of these two species demonstrated anorexia, depression, and neurologic signs and typically were moribund or dead within 2 days of the onset of clinical signs. Gross lesions were mild or absent in house finches and budgerigars. Histologically, the brain and pancreas were the most consistently and severely affected organs in house finches. The brain was the most affected organ in budgerigars. Unlike these three species, house sparrows suffered only mild transient depression, had no mortality, and lacked gross lesions. Viral antigen and microscopic lesions were observed only in the heart and testicle of a minority of birds of this species. Starlings demonstrated neither clinical disease nor mortality and lacked gross and histologic lesions. Viral antigen was not observed in any of the collected tissues from starlings. These results indicate that there is significant variation in the pathogenicity of the chicken/Hong Kong virus for different species of birds, including species within the same order. In addition, neurotropism is a recurrent feature among birds that eventually succumb to

  9. PCR primers and probes for the 16S rRNA gene of most species of pathogenic bacteria, including bacteria found in cerebrospinal fluid.

    PubMed Central

    Greisen, K; Loeffelholz, M; Purohit, A; Leong, D

    1994-01-01

    A set of broad-range PCR primers for the 16S rRNA gene in bacteria were tested, along with three series of oligonucleotide probes to detect the PCR product. The first series of probes is broad in range and consists of a universal bacterial probe, a gram-positive probe, a Bacteroides-Flavobacterium probe, and two probes for other gram-negative species. The second series was designed to detect PCR products from seven major bacterial species or groups frequently causing meningitis: Neisseria meningitidis, Haemophilus influenzae, Streptococcus pneumoniae, S. agalactiae, Escherichia coli and other enteric bacteria, Listeria monocytogenes, and Staphylococcus aureus. The third series was designed for the detection of DNA from species or genera commonly considered potential contaminants of clinical samples, including cerebrospinal fluid (CSF): Bacillus, Corynebacterium, Propionibacterium, and coagulase-negative Staphylococcus spp. The primers amplified DNA from all 124 different species of bacteria tested. Southern hybridization testing of the broad-range probes with washes containing 3 M tetramethylammonium chloride indicated that this set of probes correctly identified all but two of the 102 bacterial species tested, the exceptions being Deinococcus radiopugnans and Gardnerella vaginalis. The gram-negative and gram-positive probes hybridized to isolates of two newly characterized bacteria, Alloiococcus otitis and Rochalimaea henselii, as predicted by Gram stain characteristics. The CSF pathogen and contaminant probe sequences were compared with available sequence information and with sequencing data for 32 different species. Testing of the CSF pathogen and contaminant probes against DNA from over 60 different strains indicated that, with the exception of the coagulase-negative Staphylococcus probes, these probes provided the correct identification of bacterial species known to be found in CSF. Images PMID:7512093

  10. Screening of tea extract and theaflavins for inhibitory effects on the biological activity and production of staphylococcal enterotoxin A.

    PubMed

    Shimamura, Yuko; Aoki, Natsumi; Sugiyama, Yuka; Nakayama, Tsutomu; Masuda, Shuichi

    2014-11-01

    This study aimed to develop a novel method with tea extracts and its components, to reduce the risk of foodborne illnesses caused by the bacterial toxin staphylococcal enterotoxin A (SEA). The potential effect of tea extracts, theaflavins, and epitheaflagallin on staphylococcal growth was studied. A broth microdilution method was used to determine the minimum inhibitory concentration of these samples against an SEA-producing strain, Staphylococcus aureus C-29. The following assays were performed to evaluate various effects on concentrations of no effect on staphylococcal growth. The interactions of theaflavin-rich green tea extracts (TGE), theaflavins, and epitheaflagallin to cultured S. aureus C-29 were determined using Western blot analysis. As a result, all samples suppressed the binding affinity of the anti-SEA antibody to SEA. Since these samples could react directly with SEA, we examined whether they could bind to SEA. Our results demonstrated that binding of the anti-SEA antibody to 4 theaflavins-treated SEA was inhibited in a dose-dependent manner. On the other hand, the production of SEA was significantly decreased by treatment with TGE and epitheaflagallin. Based on the finding that TGE and epitheaflagallin inhibit the production of SEA, we further examined the relative expression levels of sea toxin-encoding genes after treatment with TGE and epitheaflagallin with real-time RT-PCR. TGE and epitheaflagallin significantly supressed the gene transcription of SEA in S. aureus C-29. We then tested whether the samples block the biological activity of SEA in murine spleen cells. TGE, theaflavins, and epitheaflagallin became inactivated the biological activity of SEA. These results suggest that edible and safe compounds in tea can be used to inactivate both pathogens and toxins.

  11. Staphylococcal persistence due to biofilm formation in synovial fluid containing prophylactic cefazolin.

    PubMed

    Dastgheyb, Sana S; Hammoud, Sommer; Ketonis, Constantinos; Liu, Andrew Yongkun; Fitzgerald, Keith; Parvizi, Javad; Purtill, James; Ciccotti, Michael; Shapiro, Irving M; Otto, Michael; Hickok, Noreen J

    2015-04-01

    Antibiotic prophylaxis is standard for patients undergoing surgical procedures, yet despite the wide use of antibiotics, breakthrough infections still occur. In the setting of total joint arthroplasty, such infections can be devastating. Recent findings have shown that synovial fluid causes marked staphylococcal aggregation, which can confer antibiotic insensitivity. We therefore asked in this study whether clinical samples of synovial fluid that contain preoperative prophylactic antibiotics can successfully eradicate a bacterial challenge by pertinent bacterial species. This study demonstrates that preoperative prophylaxis with cefazolin results in high antibiotic levels. Furthermore, we show that even with antibiotic concentrations that far exceed the expected bactericidal levels, Staphylococcus aureus bacteria added to the synovial fluid samples are not eradicated and are able to colonize model implant surfaces, i.e., titanium pins. Based on these studies, we suggest that current prophylactic antibiotic choices, despite high penetration into the synovial fluid, may need to be reexamined. PMID:25624333

  12. Staphylococcal Persistence Due to Biofilm Formation in Synovial Fluid Containing Prophylactic Cefazolin

    PubMed Central

    Dastgheyb, Sana S.; Hammoud, Sommer; Ketonis, Constantinos; Liu, Andrew Yongkun; Fitzgerald, Keith; Parvizi, Javad; Purtill, James; Ciccotti, Michael; Shapiro, Irving M.; Otto, Michael

    2015-01-01

    Antibiotic prophylaxis is standard for patients undergoing surgical procedures, yet despite the wide use of antibiotics, breakthrough infections still occur. In the setting of total joint arthroplasty, such infections can be devastating. Recent findings have shown that synovial fluid causes marked staphylococcal aggregation, which can confer antibiotic insensitivity. We therefore asked in this study whether clinical samples of synovial fluid that contain preoperative prophylactic antibiotics can successfully eradicate a bacterial challenge by pertinent bacterial species. This study demonstrates that preoperative prophylaxis with cefazolin results in high antibiotic levels. Furthermore, we show that even with antibiotic concentrations that far exceed the expected bactericidal levels, Staphylococcus aureus bacteria added to the synovial fluid samples are not eradicated and are able to colonize model implant surfaces, i.e., titanium pins. Based on these studies, we suggest that current prophylactic antibiotic choices, despite high penetration into the synovial fluid, may need to be reexamined. PMID:25624333

  13. Staphylococcal food poisoning from sheep milk cheese.

    PubMed Central

    Bone, F. J.; Bogie, D.; Morgan-Jones, S. C.

    1989-01-01

    Cheese made from sheep milk was implicated in food-poisoning incidents in December 1984 and January 1985. Bacteriological examination of batches of cheese failed to reveal a viable pathogen but enterotoxin A produced by Staphylococcus aureus was present. This was the first time that enterotoxin was detected in a food produced in the UK which was associated with poisoning and from which viable Staph. aureus could not be isolated. Subsequent detailed examination of milk, yoghurt and cheese from the same producer revealed that contamination with Staph. aureus was associated with post-infection carriage as well as clinical illness in ewes on the farm. Strains producing enterotoxon. A were still intermittently present in the bulk milk used for cheese production nearly 2 years afterwards, apparently in the absence of clinical illness in the sheep. The possible effects of heat treatment are discussed. Any changes in legislation should cover all non-human mammalian milk used for human consumption. PMID:2691265

  14. Evidence-Based Structural Model of the Staphylococcal Repressor Protein: Separation of Functions into Different Domains

    PubMed Central

    Nyíri, Kinga; Kőhegyi, Bianka; Micsonai, András; Kardos, József; Vertessy, Beata G.

    2015-01-01

    Horizontal transfer of mobile genetic elements within Staphylococci is of high biomedical significance as such elements are frequently responsible for virulence and toxic effects. Staphylococcus-encoded repressor proteins regulate the replication of these mobile genetic elements that are located within the so-called pathogenicity islands. Here, we report structural and functional characterization of one such repressor protein, namely the Stl protein encoded by the pathogenicity island SaPIbov1. We create a 3D structural model and based on this prediction, we investigate the different functionalities of truncated and point mutant constructs. Results suggest that a helix-turn-helix motif governs the interaction of the Stl protein with its cognate DNA site: point mutations within this motif drastically decrease DNA-binding ability, whereas the interaction with the Stl-binding partner protein dUTPase is unperturbed by these point mutations. The 3D model also suggested the potential independent folding of a carboxy-terminal domain. This suggestion was fully verified by independent experiments revealing that the carboxy-terminal domain does not bind to DNA but is still capable of binding to and inhibiting dUTPase. A general model is proposed, which suggests that among the several structurally different repressor superfamilies Stl-like Staphylococcal repressor proteins belong to the helix-turn-helix transcription factor group and the HTH motif is suggested to reside within N-terminal segment. PMID:26414067

  15. Zinc oxide nanoparticle suspensions and layer-by-layer coatings inhibit staphylococcal growth.

    PubMed

    McGuffie, Matthew J; Hong, Jin; Bahng, Joong Hwan; Glynos, Emmanouil; Green, Peter F; Kotov, Nicholas A; Younger, John G; VanEpps, J Scott

    2016-01-01

    Despite a decade of engineering and process improvements, bacterial infection remains the primary threat to implanted medical devices. Zinc oxide nanoparticles (ZnO-NPs) have demonstrated antimicrobial properties. Their microbial selectivity, stability, ease of production, and low cost make them attractive alternatives to silver NPs or antimicrobial peptides. Here we sought to (1) determine the relative efficacy of ZnO-NPs on planktonic growth of medically relevant pathogens; (2) establish the role of bacterial surface chemistry on ZnO-NP effectiveness; (3) evaluate NP shape as a factor in the dose-response; and (4) evaluate layer-by-layer (LBL) ZnO-NP surface coatings on biofilm growth. ZnO-NPs inhibited bacterial growth in a shape-dependent manner not previously seen or predicted. Pyramid shaped particles were the most effective and contrary to previous work, larger particles were more effective than smaller particles. Differential susceptibility of pathogens may be related to their surface hydrophobicity. LBL ZnO-NO coatings reduced staphylococcal biofilm burden by >95%. From the Clinical Editor: The use of medical implants is widespread. However, bacterial colonization remains a major concern. In this article, the authors investigated the use of zinc oxide nanoparticles (ZnO-NPs) to prevent bacterial infection. They showed in their experiments that ZnO-NPs significantly inhibited bacterial growth. This work may present a new alternative in using ZnO-NPs in medical devices. PMID:26515755

  16. The improved PCR of the fstA (ferric siderophore receptor) gene differentiates the fish pathogen Aeromonas salmonicida from other Aeromonas species.

    PubMed

    Beaz-Hidalgo, Roxana; Latif-Eugenín, Fadua; Figueras, María José

    2013-10-25

    The members of the genus Aeromonas are autochthonous of aquatic ecosystems and several species have been associated to septicaemia, ulcerative and haemorrhagic diseases in fish, causing significant mortality in both wild and farmed, freshwater and marine fish species. The species Aeromonas salmonicida is generally recognized as the most important fish pathogen responsible for epidemic outbreaks of furunculosis in salmonids, also being able to produce infections in other cultured fish such as turbot, halibut, sea bream or goldfish. New species, i.e. Aeromonas aquariorum, Aeromonas tecta and Aeromonas piscicola, have recently been discovered and isolated from diseased fish. The species A. piscicola and Aeromonas bestiarum are practically impossible to differentiate phenotypically and genetically (when using the 16S rRNA gene) from each other and from A. salmonicida. In the present study, two previously described PCR protocols, based on the fstA and gyrB genes, for the specific detection of A. salmonicida were re-evaluated with the type strains of all Aeromonas species and with a set of A. piscicola and A. bestiarum strains. Contrary to what had been published previously it was demonstrated that the gyrB-PCR is not specific for A. salmonicida because of cross-reactions with other Aeromonas species. However, in agreement with previous results, A. salmonicida was detected on the basis of the fstA-PCR, for which an improved protocol was proposed. PMID:23890674

  17. Host species-specific conservation of a family of repeated DNA sequences in the genome of a fungal plant pathogen.

    PubMed Central

    Hamer, J E; Farrall, L; Orbach, M J; Valent, B; Chumley, F G

    1989-01-01

    We have identified a family of dispersed repetitive DNA sequences in the genome of Magnaporthe grisea, the fungus that causes rice blast disease. We have named this family of DNA sequences "MGR" for M. grisea repeat. Analysis of five MGR clones demonstrates that MGR sequences are highly polymorphic. The segregation of MGR sequences in genetic crosses and hybridization of MGR probes to separated, chromosome-size DNA molecules of M. grisea shows that this family of sequences is distributed among the M. grisea chromosomes. MGR sequences also hybridize to discrete poly(A)+ RNAs. Southern blot analysis using a MGR probe can distinguish rice pathogens from various sources. However, MGR sequences are not highly conserved in the genomes of M. grisea field isolates that do not infect rice. These results suggest that host selection for a specific pathogen genotype has occurred during the breeding and cultivation of rice. Images PMID:2602385

  18. Following the infection process of vibriosis in Manila clam (Ruditapes philippinarum) larvae through GFP-tagged pathogenic Vibrio species.

    PubMed

    Dubert, Javier; Nelson, David R; Spinard, Edward J; Kessner, Linda; Gomez-Chiarri, Marta; da Costa, Fiz; Prado, Susana; Barja, Juan L

    2016-01-01

    Vibriosis represents the main bottleneck for the larval production process in shellfish aquaculture. While the signs of this disease in bivalve larvae are well known, the infection process by pathogenic Vibrio spp. during episodes of vibriosis has not been elucidated. To investigate the infection process in bivalves, the pathogens of larvae as V. tubiashii subsp. europaensis, V. neptunius and V. bivalvicida were tagged with green fluorescent protein (GFP). Larvae of Manila clam (Ruditapes philippinarum) were inoculated with the GFP-labeled pathogens in different infection assays and monitored by microscopy. Manila clam larvae infected by distinct GFP-tagged Vibrio spp. in different challenges showed the same progression in the infection process, defining three infection stages. GFP-tagged Vibrio spp. were filtered by the larvae through the vellum and entered in the digestive system through the esophagus and stomach and colonized the digestive gland and particularly the intestine, where they proliferated during the first 2h of contact (Stage I), suggesting a chemotactic response. Then, GFP-tagged Vibrio spp. expanded rapidly to the surrounding organs in the body cavity from the dorsal to ventral region (Stage II; 6-8h), colonizing the larvae completely at the peak of infection (Stage III) (14-24h). Results demonstrated for the first time that the vibriosis is asymptomatic in Manila clam larvae during the early infection stages. Thus, the early colonization and the rapid proliferation of Vibrio pathogens within the body cavity supported the sudden and fatal effect of the vibriosis, since the larvae exhibited the first signs of disease when the infection process is advanced. As a first step in the elucidation of the potential mechanisms of bacterial pathogenesis in bivalve larvae the enzymatic activities of the extracellular products released from the wild type V. neptunius, V. tubiashii subsp. europaensis and V. bivalvicida were determined and their cytotoxicity was

  19. PB2-Q591K Mutation Determines the Pathogenicity of Avian H9N2 Influenza Viruses for Mammalian Species

    PubMed Central

    Wang, Congrong; Lee, Horace Hok Yeung; Yang, Zi Feng; Mok, Chris Ka Pun; Zhang, Zhi

    2016-01-01

    Background Influenza A subtype H9N2 is widespread and prevalent in poultry. It has repeatedly transmitted zoonotically to cause mild influenza-like illness in humans and is regarded as a potential pandemic candidate. In additon, the six internal genes of H7N9 and H10N8 viruses which caused infection in human in China as well as some of the highly pathogenic H5N1 strains are origined from H9N2. Previous studies have shown that the mammalian adaptation PB2-Q591K contributes to the pathogenicity of H5N1 and H7N9 viruses. However, the role of the PB2-Q591K mutation in H9N2 subtype is still not well understood. Methods To define and compare the individual role of PB2-Q591K substitution in the PB2 gene segment of H9N2 in relation to polymerase activity, replication competence and the pathogenicity using in vitro and in vivo models. Results The PB2-Q591K mutation in H9N2 virus enhanced the polymerase activity and virus replication in human NHBE cells when compared to the wild type strain. Mice infected with the PB2 mutant showed significant weight loss, higher virus replication and immune responses in the lungs. Conclusions Our evidences suggest that the PB2-Q591K, in addition to the -E627K mutation in H9N2 enhanced the pathogenicity in mammalian host. PMID:27684944

  20. Antifungal Activity of a Synthetic Cationic Peptide against the Plant Pathogens Colletotrichum graminicola and Three Fusarium Species

    PubMed Central

    Johnson, Eric T.; Evans, Kervin O.; Dowd, Patrick F.

    2015-01-01

    A small cationic peptide (JH8944) was tested for activity against a number of pathogens of agricultural crops. JH8944 inhibited conidium growth in most of the tested plant pathogens with a dose of 50 μg/ml, although one isolate of Fusarium oxysporum was inhibited at 5 μg/ml of JH8944. Most conidia of Fusarium graminearum were killed within 6 hours of treatment with 50 μg/ml of JH8944. Germinating F. graminearum conidia required 238 μg/ml of JH8944 for 90% growth inhibition. The peptide did not cause any damage to tissues surrounding maize leaf punctures when tested at a higher concentration of 250 μg/ml even after 3 days. Liposomes consisting of phosphatidylglycerol were susceptible to leakage after treatment with 25 and 50 μg/ml of JH8944. These experiments suggest this peptide destroys fungal membrane integrity and could be utilized for control of crop fungal pathogens. PMID:26361481

  1. Presence and persistence of wastewater pathogen Escherichia coli O157:H7 in hydroponic reactors of treatment wetland species.

    PubMed

    VanKempen-Fryling, R J; Stein, O R; Camper, A K

    2015-01-01

    Treatment wetlands (TWs) efficiently remove many pollutants including a several log order reduction of pathogens from influent to effluent; however, there is evidence to suggest that pathogen cells are sequestered in a subsurface wetland and may remain viable months after inoculation. Escherichia coli is a common pathogen in domestic and agricultural wastewater and the O157:H7 strain causes most environmental outbreaks in the United States. To assess attachment of E. coli to the TW rhizosphere, direct measurements of E. coli levels were taken. Experiments were performed in chemostats containing either Teflon nylon as an abiotic control or roots of Carex utriculata or Schoenoplectus acutus. Flow of simulated wastewater through the chemostat was set to maintain a 2 hour residence time. The influent was inoculated with E. coli O157:H7 containing DsRed fluorescent protein. Root samples were excised and analyzed via epifluorescent microscopy. E. coli O157:H7 was detected on the root surface at 2 hours after inoculation, and were visible as single cells. Microcolonies began forming at 24 hours post-inoculation and were detected for up to 1 week post-inoculation. Image analysis determined that the number of microcolonies with >100 cells increased 1 week post-inoculation, confirming that E. coli O157:H7 is capable of growth within biofilms surrounding wetland plant roots. PMID:26114281

  2. Presence and persistence of wastewater pathogen Escherichia coli O157:H7 in hydroponic reactors of treatment wetland species.

    PubMed

    VanKempen-Fryling, R J; Stein, O R; Camper, A K

    2015-01-01

    Treatment wetlands (TWs) efficiently remove many pollutants including a several log order reduction of pathogens from influent to effluent; however, there is evidence to suggest that pathogen cells are sequestered in a subsurface wetland and may remain viable months after inoculation. Escherichia coli is a common pathogen in domestic and agricultural wastewater and the O157:H7 strain causes most environmental outbreaks in the United States. To assess attachment of E. coli to the TW rhizosphere, direct measurements of E. coli levels were taken. Experiments were performed in chemostats containing either Teflon nylon as an abiotic control or roots of Carex utriculata or Schoenoplectus acutus. Flow of simulated wastewater through the chemostat was set to maintain a 2 hour residence time. The influent was inoculated with E. coli O157:H7 containing DsRed fluorescent protein. Root samples were excised and analyzed via epifluorescent microscopy. E. coli O157:H7 was detected on the root surface at 2 hours after inoculation, and were visible as single cells. Microcolonies began forming at 24 hours post-inoculation and were detected for up to 1 week post-inoculation. Image analysis determined that the number of microcolonies with >100 cells increased 1 week post-inoculation, confirming that E. coli O157:H7 is capable of growth within biofilms surrounding wetland plant roots.

  3. Emergence of mammalian species-infectious and -pathogenic avian influenza H6N5 virus with no evidence of adaptation.

    PubMed

    Nam, Jeong-Hyun; Kim, Eun-Ha; Song, Daesub; Choi, Young Ki; Kim, Jeong-Ki; Poo, Haryoung

    2011-12-01

    The migratory waterfowl of the world are considered to be the natural reservoir of influenza A viruses. Of the 16 hemagglutinin subtypes of avian influenza viruses, the H6 subtype is commonly perpetuated in its natural hosts and is of concern due to its potential to be a precursor of highly pathogenic influenza viruses by reassortment. During routine influenza surveillance, we isolated an unconventional H6N5 subtype of avian influenza virus. Experimental infection of mice revealed that this isolate replicated efficiently in the lungs, subsequently spread systemically, and caused lethality. The isolate also productively infected ferrets, with direct evidence of contact transmission, but no disease or transmission was seen in pigs. Although the isolate possessed the conserved receptor-binding site sequences of avian influenza viruses, it exhibited relatively low replication efficiencies in ducks and chickens. Our genetic and molecular analyses of the isolate revealed that its PB1 sequence showed the highest evolutionary relationship to those of highly pathogenic H5N1 avian influenza viruses and that its PA protein had an isoleucine residue at position 97 (a representative virulence marker). Further studies will be required to examine why our isolate has the virologic characteristics of mammalian influenza viruses but the archetypal receptor binding profiles of avian influenza viruses, as well as to determine whether its potential virulence markers (PB1 analogous to those of H5N1 viruses or isoleucine residue at position 97 within PA) could render it highly pathogenic in mice. PMID:21994462

  4. Antifungal Activity of a Synthetic Cationic Peptide against the Plant Pathogens Colletotrichum graminicola and Three Fusarium Species.

    PubMed

    Johnson, Eric T; Evans, Kervin O; Dowd, Patrick F

    2015-09-01

    A small cationic peptide (JH8944) was tested for activity against a number of pathogens of agricultural crops. JH8944 inhibited conidium growth in most of the tested plant pathogens with a dose of 50 μg/ml, although one isolate of Fusarium oxysporum was inhibited at 5 μg/ml of JH8944. Most conidia of Fusarium graminearum were killed within 6 hours of treatment with 50 μg/ml of JH8944. Germinating F. graminearum conidia required 238 μg/ml of JH8944 for 90% growth inhibition. The peptide did not cause any damage to tissues surrounding maize leaf punctures when tested at a higher concentration of 250 μg/ml even after 3 days. Liposomes consisting of phosphatidylglycerol were susceptible to leakage after treatment with 25 and 50 μg/ml of JH8944. These experiments suggest this peptide destroys fungal membrane integrity and could be utilized for control of crop fungal pathogens. PMID:26361481

  5. [Ceftriaxone in the treatment of staphylococcal endocarditis].

    PubMed

    Demin, A A; Drobysheva, V P

    1998-01-01

    Efficacy and safety of ceftriaxone (Oframax, Ranbaxy, India) in the treatment of 25 patients with Staphylococcus endocarditis (SE) were studied. The drug was administered intravenously in a dose of 2-4 g a day for 4 weeks and simultaneously gentamicin was used intramuscularly in a dose of 2-3 mg/kg body weight a day every 8 hours for 2 weeks. The treatment was followed by observation of the patients for up to 2 years under the hospital or dyspensary conditions. The disease was due to S. epidermidis (17 patients) or S.aureus (8 patients). The efficacy was controlled in the dynamics. The criteria of the therapy efficacy were disappearance of the disease clinical signs, normalization of the blood count and urinalysis and the pathogen eradication by the results of the control bacteriological blood analysis. The cure without any surgical correction was observed in 68 per cent of the patients and that with the valve replacement was stated in 24 per cent of the patients. The lethal outcome due to bacteriotoxic shock was recorded in 8 per cent of the patients. The SE relapsing was stated in 28 per cent of the patients 3 or more months after the ceftriaxone therapy completion. 10 patients (40 per cent) with evident clinicolaboratory improvement were discharged from the hospital 2 (4 patients) and 3 (6 patients) weeks after the therapy start for the treatment with ceftriaxone as outpatients. In 2 patients nausea as the adverse reaction was observed. Therefore, the complex clinicolaboratory investigation showed that the combined use of ceftriaxone and gentamicin was efficient and safe in the treatment of SE. Ceftriaxone may be considered as a basic drug for the therapy of SE. In some patients with SE the treatment with ceftriaxone may be completed under outpatient conditions.

  6. The Diaporthe sojae species complex: phylogenetic re-assessment of pathogens associated with soybean, cucurbits and other field crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phytopathogenic species of Diaporthe are associated with the serious diseases including seed decay, pod and stem blight and stem canker of soybean leading to considerable loss of crop production worldwide. Accurate identification of the species that cause these diseases has been difficult due to the...

  7. Surface plasmon resonance (SPR) detection of Staphylococcal Enterotoxin A in food samples

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An automated and rapid method for detection of staphylococcal enterotoxins (SE) is needed. A sandwich assay was developed using a surface plasmon resonance (SPR) biosensor for detection of staphylococcal enterotoxin A (SEA) at subpicomolar concentration. Assay conditions were optimized for capturing...

  8. [Pathogenicity expressed by inhibition of the Pasteur effect].

    PubMed

    Dragomirescu, M; Marţincu, V; Novac, E

    1977-01-01

    The experiments carried out demonstrate that under the influence of tetanus exotoxin, Gram-negative bacteria endotoxins, staphylococcal infection and infestation with Tr. spiralis, inhibition of the Pasteur effect occurs. Recently published data show that the same manifestation of pathogenicity is induced by diphtheria alpha and delta exotoxin, staphylococcal toxin, Pseudomonas aeruginosa exotoxin, staphylococcal enterotoxin, streptolysin O, infections with Cl. perfringens, Pasteurella and Rickettsia and hepatitis viruses in man. These data confirm a previous hypothesis according to which inhibition of the Pasteur effect represents the expression and metabolic measure of pathogenicity and toxicity. The inhibitory effect was proportional to the amount of pathogenic agent or toxin, just as the respective anatoxin or toxin + endotoxin mixture does not influence the Pasteur effect. The metabolic criteria of the Pasteur effect, i.e. inhibition of hyperlactacidaemia and decrease of the organic P/inorganic P ratio, are thus the direct indices of pathogenicity and toxigenicity. This also accounts for deep alteration of the Pasteur effect in infections generating states of infectious and endotoxinic shock.

  9. Spatiotemporal Analysis of Cryptosporidium Species/Genotypes and Relationships with Other Zoonotic Pathogens in Surface Water from Mixed-Use Watersheds

    PubMed Central

    Wilkes, Graham; Ruecker, Norma J.; Neumann, Norman F.; Gannon, Victor P. J.; Jokinen, Cassandra; Sunohara, Mark; Topp, Edward; Pintar, Katarina D. M.; Edge, Thomas A.

    2013-01-01

    Nearly 690 raw surface water samples were collected during a 6-year period from multiple watersheds in the South Nation River basin, Ontario, Canada. Cryptosporidium oocysts in water samples were enumerated, sequenced, and genotyped by detailed phylogenetic analysis. The resulting species and genotypes were assigned to broad, known host and human infection risk classes. Wildlife/unknown, livestock, avian, and human host classes occurred in 21, 13, 3, and <1% of sampled surface waters, respectively. Cryptosporidium andersoni was the most commonly detected livestock species, while muskrat I and II genotypes were the most dominant wildlife genotypes. The presence of Giardia spp., Salmonella spp., Campylobacter spp., and Escherichia coli O157:H7 was evaluated in all water samples. The greatest significant odds ratios (odds of pathogen presence when host class is present/odds of pathogen presence when host class is absent) for Giardia spp., Campylobacter spp., and Salmonella spp. in water were associated, respectively, with livestock (odds ratio of 3.1), avian (4.3), and livestock (9.3) host classes. Classification and regression tree analyses (CART) were used to group generalized host and human infection risk classes on the basis of a broad range of environmental and land use variables while tracking cooccurrence of zoonotic pathogens in these groupings. The occurrence of livestock-associated Cryptosporidium was most strongly related to agricultural water pollution in the fall (conditions also associated with elevated odds ratios of other zoonotic pathogens occurring in water in relation to all sampling conditions), whereas wildlife/unknown sources of Cryptosporidium were geospatially associated with smaller watercourses where urban/rural development was relatively lower. Conditions that support wildlife may not necessarily increase overall human infection risks associated with Cryptosporidium since most Cryptosporidium genotypes classed as wildlife in this study (e

  10. Staphylococcal Bicomponent Pore-Forming Toxins: Targets for Prophylaxis and Immunotherapy

    PubMed Central

    Aman, M. Javad; Adhikari, Rajan P.

    2014-01-01

    Staphylococccus aureus represents one of the most challenging human pathogens as well as a common colonizer of human skin and mucosal surfaces. S. aureus causes a wide range of diseases from skin and soft tissue infection (SSTI) to debilitating and life-threatening conditions such as osteomyelitis, endocarditis, and necrotizing pneumonia. The range of diseases reflects the remarkable diversity of the virulence factors produced by this pathogen, including surface antigens involved in the establishment of infection and a large number of toxins that mediate a vast array of cellular responses. The staphylococcal toxins are generally believed to have evolved to disarm the innate immune system, the first line of defense against this pathogen. This review focuses on recent advances on elucidating the biological functions of S. aureus bicomponent pore-forming toxins (BCPFTs) and their utility as targets for preventive and therapeutic intervention. These toxins are cytolytic to a variety of immune cells, primarily neutrophils, as well as cells with a critical barrier function. The lytic activity of BCPFTs towards immune cells implies a critical role in immune evasion, and a number of epidemiological studies and animal experiments relate these toxins to clinical disease, particularly SSTI and necrotizing pneumonia. Antibody-mediated neutralization of this lytic activity may provide a strategy for development of toxoid-based vaccines or immunotherapeutics for prevention or mitigation of clinical diseases. However, certain BCPFTs have been proposed to act as danger signals that may alert the immune system through an inflammatory response. The utility of a neutralizing vaccination strategy must be weighed against such immune-activating potential. PMID:24599233

  11. Staphylococcal bicomponent pore-forming toxins: targets for prophylaxis and immunotherapy.

    PubMed

    Aman, M Javad; Adhikari, Rajan P

    2014-03-04

    Staphylococccus aureus represents one of the most challenging human pathogens as well as a common colonizer of human skin and mucosal surfaces. S. aureus causes a wide range of diseases from skin and soft tissue infection (SSTI) to debilitating and life-threatening conditions such as osteomyelitis, endocarditis, and necrotizing pneumonia. The range of diseases reflects the remarkable diversity of the virulence factors produced by this pathogen, including surface antigens involved in the establishment of infection and a large number of toxins that mediate a vast array of cellular responses. The staphylococcal toxins are generally believed to have evolved to disarm the innate immune system, the first line of defense against this pathogen. This review focuses on recent advances on elucidating the biological functions of S. aureus bicomponent pore-forming toxins (BCPFTs) and their utility as targets for preventive and therapeutic intervention. These toxins are cytolytic to a variety of immune cells, primarily neutrophils, as well as cells with a critical barrier function. The lytic activity of BCPFTs towards immune cells implies a critical role in immune evasion, and a number of epidemiological studies and animal experiments relate these toxins to clinical disease, particularly SSTI and necrotizing pneumonia. Antibody-mediated neutralization of this lytic activity may provide a strategy for development of toxoid-based vaccines or immunotherapeutics for prevention or mitigation of clinical diseases. However, certain BCPFTs have been proposed to act as danger signals that may alert the immune system through an inflammatory response. The utility of a neutralizing vaccination strategy must be weighed against such immune-activating potential.

  12. Export of the HR eliciting protein, Harpin(Es), of the maize pathogen Erwinia stewartii is species-specific but is independent of the growth temperature.

    PubMed

    Ahmad, Musharaf; Alam, Syed Sartaj; Alam, Shah; Usman, Amjad; Coplin, David L

    2007-01-01

    The extra-cellular export of the HR-eliciting protein, Harpin(Es) of the maize pathogen Erwinia stewartii was studied to find out if the protein needs any species-specific signal for its export and to determine if the export of the protein to the medium is affected in any way by the growth temperature. Based upon the experimental evidence, it was proved that the protein (i.e., Harpin(Es)) does require its own export system (species-specific) to get out of the bacterial cell and can not be exported by the export system of even the very closely related bacterium, Erwinia amylovora. It was also found that the export of Harpin(Es) is, unlike the case of Harpin(Ea) (HR-eliciting protein of Erwinia amylovora), independent of the growth temperature.

  13. Identification and Characterization of a Novel Staphylococcal Emetic Toxin.

    PubMed

    Ono, Hisaya K; Sato'o, Yusuke; Narita, Kouji; Naito, Ikunori; Hirose, Shouhei; Hisatsune, Junzo; Asano, Krisana; Hu, Dong-Liang; Omoe, Katsuhiko; Sugai, Motoyuki; Nakane, Akio

    2015-10-01

    Staphylococcal enterotoxins (SEs) produced by Staphylococcus aureus have superantigenic and emetic activities, which cause toxic shock syndrome and staphylococcal food poisoning, respectively. Our previous study demonstrated that the sequence of SET has a low level of similarity to the sequences of other SEs and exhibits atypical bioactivities. Hence, we further explored whether there is an additional SET-related gene in S. aureus strains. One SET-like gene was found in the genome of S. aureus isolates that originated from a case of food poisoning, a human nasal swab, and a case of bovine mastitis. The deduced amino acid sequence of the SET-like gene showed 32% identity with the amino acid sequence of SET. The SET-like gene product was designated SElY. In the food poisoning and nasal swab isolates, mRNA encoding SElY was highly expressed in the early log phase of cultivation, whereas a high level of expression of this mRNA was found in the bovine mastitis isolate at the early stationary phase. To estimate whether SElY has both superantigenic and emetic activities, recombinant SElY was prepared. Cell proliferation and cytokine production were examined to assess the superantigenic activity of SElY. SElY exhibited superantigenic activity in human peripheral blood mononuclear cells but not in mouse splenocytes. In addition, SElY exhibited emetic activity in house musk shrews after intraperitoneal and oral administration. However, the stability of SElY against heating and pepsin and trypsin digestion was different from that of SET and SEA. From these results, we identified SElY to be a novel staphylococcal emetic toxin. PMID:26231643

  14. APOBEC3G polymorphism as a selective barrier to cross-species transmission and emergence of pathogenic SIV and AIDS in a primate host.

    PubMed

    Krupp, Annabel; McCarthy, Kevin R; Ooms, Marcel; Letko, Michael; Morgan, Jennifer S; Simon, Viviana; Johnson, Welkin E

    2013-01-01

    Cellular restriction factors, which render cells intrinsically resistant to viruses, potentially impose genetic barriers to cross-species transmission and emergence of viral pathogens in nature. One such factor is APOBEC3G. To overcome APOBEC3G-mediated restriction, many lentiviruses encode Vif, a protein that targets APOBEC3G for degradation. As with many restriction factor genes, primate APOBEC3G displays strong signatures of positive selection. This is interpreted as evidence that the primate APOBEC3G locus reflects a long-term evolutionary "arms-race" between retroviruses and their primate hosts. Here, we provide direct evidence that APOBEC3G has functioned as a barrier to cross-species transmission, selecting for viral resistance during emergence of the AIDS-causing pathogen SIVmac in captive colonies of Asian macaques in the 1970s. Specifically, we found that rhesus macaques have multiple, functionally distinct APOBEC3G alleles, and that emergence of SIVmac and simian AIDS required adaptation of the virus to evade APOBEC3G-mediated restriction. Our evidence includes the first comparative analysis of APOBEC3G polymorphism and function in both a reservoir and recipient host species (sooty mangabeys and rhesus macaques, respectively), and identification of adaptations unique to Vif proteins of the SIVmac lineage that specifically antagonize rhesus APOBEC3G alleles. By demonstrating that interspecies variation in a known restriction factor selected for viral counter-adaptations in the context of a documented case of cross-species transmission, our results lend strong support to the evolutionary "arms-race" hypothesis. Importantly, our study confirms that APOBEC3G divergence can be a critical determinant of interspecies transmission and emergence of primate lentiviruses, including viruses with the potential to infect and spread in human populations.

  15. Purification and Characterization of a Rabbit Serum Factor That Kills Listeria Species and Other Foodborne Bacterial Pathogens.

    PubMed

    Kothary, Mahendra H; Franco, Augusto A; Tall, Ben D; Gopinath, Gopal R; Datta, Atin R

    2016-08-01

    In an in-vitro assay, rabbit serum, but not human serum, killed Listeria monocytogenes, a foodborne pathogen. The aim of our study was to purify and partially characterize this killing factor. Listericidin was purified from rabbit serum by a single-step ion-exchange chromatography with DEAE-Sephadex A-50 and its antimicrobial activity was assessed by a microdilution method. Listericidin is a protein with a molecular weight of 9 kDa and an isoelectric point of 8.1. It kills L. monocytogenes at 4°C, 25°C, and 37°C, and its activity is resistant to heat (boiling) and acidic conditions (pH <2). Listericidin's activity is inhibited by sodium chloride and various growth media, is sensitive to proteolytic enzymes and is enhanced by calcium chloride, and is neutralized by monoclonal antibodies to human complement C3a. However, the listericidin reacts weakly with these antibodies in an ELISA. The first 33 N-terminal residues of listericidin (SVQLTEKRMDKVGQYTNKELRKXXEDGMRDNPM) have homology to various complement C3a components. Listericidin also kills other Listeria spp., Vibrio spp., Salmonella spp., Escherichia spp., Cronobacter spp., and Bacillus spp. The listericidin peptide purified in a single-step chromatography is pH and heat stable, and has a broad antimicrobial spectrum against major foodborne pathogens in addition to L. monocytogenes. PMID:27455064

  16. Comparative Evaluation of BD Phoenix and Vitek 2 Systems for Species Identification of Common and Uncommon Pathogenic Yeasts

    PubMed Central

    Posteraro, Brunella; Ruggeri, Alberto; De Carolis, Elena; Torelli, Riccardo; Vella, Antonietta; De Maio, Flavio; Ricciardi, Walter; Posteraro, Patrizia

    2013-01-01

    The BD Phoenix system was evaluated for species-level identification of yeasts (250 clinical isolates) and compared with the Vitek 2 system, using ribosomal internal transcribed spacer (ITS) sequence analysis as the gold standard. Considering only the species included in each system's database, 96.3% (236/245) and 91.4% (224/245) of the isolates were correctly identified by BD Phoenix and Vitek 2, respectively. PMID:23966500

  17. Elucidation of bacteria found in car interiors and strategies to reduce the presence of potential pathogens.

    PubMed

    Stephenson, Rachel E; Gutierrez, Daniel; Peters, Cindy; Nichols, Mark; Boles, Blaise R

    2014-01-01

    The human microbiome is influenced by a number of factors, including environmental exposure to microbes. Because many humans spend a large amount of time in built environments, it can be expected that the microbial ecology of these environments will influence the human microbiome. In an attempt to further understand the microbial ecology of built environments, the microbiota of car interiors was analyzed using culture dependent and culture independent methods. While it was found that the number and type of bacteria varied widely among the cars and sites tested, Staphylococcus and Propionibacterium were nearly always the dominant genera found at the locations sampled. Because Staphylococcus is of particular concern to human health, the characteristics of this genus found in car interiors were investigated. Staphylococcus epidermidis, S. aureus, and S. warnerii were the most prevalent staphylococcal species found, and 22.6% of S. aureus strains isolated from shared community vehicles were resistant to methicillin. The reduction in the prevalence of pathogenic bacteria in cars by using silver-based antimicrobial surface coatings was also evaluated. Coatings containing 5% silver ion additives were applied to steering wheels, placed in cars for five months and were found to eliminate the presence of culturable pathogenic bacteria recovered from these sites relative to controls. Together, these results provide new insight into the microbiota found in an important built environment, the automobile, and potential strategies for controlling the presence of human pathogens.

  18. Elucidation of bacteria found in car interiors and strategies to reduce the presence of potential pathogens

    PubMed Central

    Stephenson, Rachel E.; Gutierrez, Daniel; Peters, Cindy; Nichols, Mark; Boles, Blaise R.

    2014-01-01

    The human microbiome is influenced by a number of factors, including environmental exposure to microbes. Because many humans spend a large amount of time in built environments, it can be expected that the microbial ecology of these environments will influence the human microbiome. In an attempt to further understand the microbial ecology of built environments, the microbiota of car interiors was analyzed using culture dependent and culture independent methods. While it was found that the number and type of bacteria varied widely among the cars and sites tested, Staphylococcus and Propionibacterium were nearly always the dominant genera found at the locations sampled. Because Staphylococcus is of particular concern to human health, the characteristics of this genus found in car interiors were investigated. Staphylococcus epidermidis, S. aureus, and S. warnerii were the most prevalent staphylococcal species found, and 22.6% of S. aureus strains isolated from shared community vehicles were resistant to methicillin. The reduction in the prevalence of pathogenic bacteria in cars by using silver-based antimicrobial surface coatings was also evaluated. Coatings containing 5% silver ion additives were applied to steering wheels, placed in cars for five months and were found to eliminate the presence of culturable pathogenic bacteria recovered from these sites relative to controls. Together, these results provide new insight into the microbiota found in an important built environment, the automobile, and potential strategies for controlling the presence of human pathogens. PMID:24564823

  19. Detection of classical and newly described staphylococcal superantigen genes in coagulase-negative staphylococci isolated from bovine intramammary infections

    PubMed Central

    Park, Joo Youn; Fox, Lawrence K.; Seo, Keun Seok; McGuire, Mark A.; Park, Yong Ho; Rurangirwa, Fred R.; Sischo, William M.; Bohach, Gregory A.

    2013-01-01

    The coagulase negative staphylococci (CNS) are the most prevalent mastitis pathogen group yet their virulence characteristics have not been well described. We investigated the presence of 19 classical and newly described staphylococcal superantigen (SAg) genes in CNS isolates from bovine intramammary infections (IMI). A total of 263 CNS representing 11 different Staphylococcus spp. were examined, and 31.2% (n = 82) of CNS isolates had one or more SAg genes; there were 21 different SAg gene combinations. The most prevalent combination of SAg genes (seb, seln, and selq; n = 45) was found in S. chromogenes, S. xylosus, S. haemolyticus, S. sciuri subsp. carnaticus, S. simulans and S. succinus. The genes for SAgs appear to be widely distributed amongst CNS isolated from bovine IMI. PMID:20667668

  20. Detection of classical and newly described staphylococcal superantigen genes in coagulase-negative staphylococci isolated from bovine intramammary infections.

    PubMed

    Park, Joo Youn; Fox, Lawrence K; Seo, Keun Seok; McGuire, Mark A; Park, Yong Ho; Rurangirwa, Fred R; Sischo, William M; Bohach, Gregory A

    2011-01-10

    The coagulase-negative staphylococci (CNS) are the most prevalent mastitis pathogen group yet their virulence characteristics have not been well described. We investigated the presence of 19 classical and newly described staphylococcal superantigen (SAg) genes in CNS isolates from bovine intramammary infections (IMI). A total of 263 CNS representing 11 different Staphylococcus spp. were examined, and 31.2% (n=82) of CNS isolates had one or more SAg genes; there were 21 different SAg gene combinations. The most prevalent combination of SAg genes (seb, seln and selq; n=45) was found in S. chromogenes, S. xylosus, S. haemolyticus, S. sciuri subsp. carnaticus, S. simulans and S. succinus. The genes for SAgs appear to be widely distributed amongst CNS isolated from bovine IMI. PMID:20667668

  1. Staph ID/R: a Rapid Method for Determining Staphylococcus Species Identity and Detecting the mecA Gene Directly from Positive Blood Culture

    PubMed Central

    Pasko, Chris; Dunn, John; Jaeckel, Heidi; Nieuwlandt, Dan; Weed, Diane; Woodruff, Evelyn; Zheng, Xiaotian

    2012-01-01

    Rapid diagnosis of staphylococcal bacteremia directs appropriate antimicrobial therapy, leading to improved patient outcome. We describe herein a rapid test (<75 min) that can identify the major pathogenic strains of Staphylococcus to the species level as well as the presence or absence of the methicillin resistance determinant gene, mecA. The test, Staph ID/R, combines a rapid isothermal nucleic acid amplification method, helicase-dependent amplification (HDA), with a chip-based array that produces unambiguous visible results. The analytic sensitivity was 1 CFU per reaction for the mecA gene and was 1 to 250 CFU per reaction depending on the staphylococcal species present in the positive blood culture. Staph ID/R has excellent specificity as well, with no cross-reactivity observed. We validated the performance of Staph ID/R by testing 104 frozen clinical positive blood cultures and comparing the results with rpoB gene or 16S rRNA gene sequencing for species identity determinations and mecA gene PCR to confirm mecA gene results. Staph ID/R agreed with mecA gene PCR for all samples and agreed with rpoB/16S rRNA gene sequencing in all cases except for one sample that contained a mixture of two staphylococcal species, one of which Staph ID/R correctly identified, for an overall agreement of 99.0% (P < 0.01). Staph ID/R could potentially be used to positively affect patient management for Staphylococcus-mediated bacteremia. PMID:22170912

  2. Molecular basis of transmembrane beta-barrel formation of staphylococcal pore-forming toxins.

    PubMed

    Yamashita, Daichi; Sugawara, Takaki; Takeshita, Miyu; Kaneko, Jun; Kamio, Yoshiyuki; Tanaka, Isao; Tanaka, Yoshikazu; Yao, Min

    2014-01-01

    Pathogenic bacteria secrete pore-forming toxins (PFTs) to attack target cells. PFTs are expressed as water-soluble monomeric proteins, which oligomerize into nonlytic prepore intermediates on the target cell membrane before forming membrane-spanning pores. Despite a wealth of biochemical data, the lack of high-resolution prepore structural information has hampered understanding of the β-barrel formation process. Here, we report crystal structures of staphylococcal γ-haemolysin and leucocidin prepores. The structures reveal a disordered bottom half of the β-barrel corresponding to the transmembrane region, and a rigid upper extramembrane half. Spectroscopic analysis of fluorescently labelled mutants confirmed that the prepore is distinct from the pore within the transmembrane region. Mutational analysis also indicates a pivotal role for the glycine residue located at the lipid-solvent interface as a 'joint' between the two halves of the β-barrel. These observations suggest a two-step transmembrane β-barrel pore formation mechanism in which the upper extramembrane and bottom transmembrane regions are formed independently. PMID:25263813

  3. Inactivation of staphylococcal virulence factors using a light-activated antimicrobial agent

    PubMed Central

    2009-01-01

    Background One of the limitations of antibiotic therapy is that even after successful killing of the infecting microorganism, virulence factors may still be present and cause significant damage to the host. Light-activated antimicrobials show potential for the treatment of topical infections; therefore if these agents can also inactivate microbial virulence factors, this would represent an advantage over conventional antibiotic therapy. Staphylococcus aureus produces a wide range of virulence factors that contribute to its success as a pathogen by facilitating colonisation and destruction of host tissues. Results In this study, the ability of the light-activated antimicrobial agent methylene blue in combination with laser light of 665 nm to inactivate staphylococcal virulence factors was assessed. A number of proteinaceous virulence factors were exposed to laser light in the presence of methylene blue and their biological activities re-determined. The activities of V8 protease, α-haemolysin and sphingomyelinase were shown to be inhibited in a dose-dependent manner by exposure to laser light in the presence of methylene blue. Conclusion These results suggest that photodynamic therapy could reduce the harmful impact of preformed virulence factors on the host. PMID:19804627

  4. Rot and SaeRS Cooperate To Activate Expression of the Staphylococcal Superantigen-Like Exoproteins

    PubMed Central

    Benson, Meredith A.; Lilo, Sarit; Nygaard, Tyler; Voyich, Jovanka M.

    2012-01-01

    Staphylococcus aureus is a significant human pathogen that is capable of infecting a wide range of host tissues. This bacterium is able to evade the host immune response by utilizing a repertoire of virulence factors. These factors are tightly regulated by various two-component systems (TCS) and transcription factors. Previous studies have suggested that transcriptional regulation of a subset of immunomodulators, known as the staphylococcal superantigen-like proteins (Ssls), is mediated by the master regulators accessory gene regulator (Agr) TCS, S. aureus exoprotein expression (Sae) TCS, and Rot. Here we demonstrate that Rot and SaeR, the response regulator of the Sae TCS, synergize to coordinate the activation of the ssl promoters. We have determined that both transcription factors are required, but that neither is sufficient, for promoter activation. This regulatory scheme is mediated by direct binding of both transcription factors to the ssl promoters. We also demonstrate that clinically relevant methicillin-resistant S. aureus (MRSA) strains respond to neutrophils via the Sae TCS to upregulate the expression of ssls. Until now, Rot and the Sae TCS have been proposed to work in opposition of one another on their target genes. This is the first example of these two regulators working in concert to activate promoters. PMID:22685286

  5. Rot and SaeRS cooperate to activate expression of the staphylococcal superantigen-like exoproteins.

    PubMed

    Benson, Meredith A; Lilo, Sarit; Nygaard, Tyler; Voyich, Jovanka M; Torres, Victor J

    2012-08-01

    Staphylococcus aureus is a significant human pathogen that is capable of infecting a wide range of host tissues. This bacterium is able to evade the host immune response by utilizing a repertoire of virulence factors. These factors are tightly regulated by various two-component systems (TCS) and transcription factors. Previous studies have suggested that transcriptional regulation of a subset of immunomodulators, known as the staphylococcal superantigen-like proteins (Ssls), is mediated by the master regulators accessory gene regulator (Agr) TCS, S. aureus exoprotein expression (Sae) TCS, and Rot. Here we demonstrate that Rot and SaeR, the response regulator of the Sae TCS, synergize to coordinate the activation of the ssl promoters. We have determined that both transcription factors are required, but that neither is sufficient, for promoter activation. This regulatory scheme is mediated by direct binding of both transcription factors to the ssl promoters. We also demonstrate that clinically relevant methicillin-resistant S. aureus (MRSA) strains respond to neutrophils via the Sae TCS to upregulate the expression of ssls. Until now, Rot and the Sae TCS have been proposed to work in opposition of one another on their target genes. This is the first example of these two regulators working in concert to activate promoters.

  6. Structural basis for inhibition of TLR2 by staphylococcal superantigen-like protein 3 (SSL3)

    PubMed Central

    Koymans, Kirsten J.; Feitsma, Louris J.; Brondijk, T. Harma C.; Aerts, Piet C.; Lukkien, Eddie; Lössl, Philip; van Kessel, Kok P. M.; de Haas, Carla J. C.; van Strijp, Jos A. G.; Huizinga, Eric G.

    2015-01-01

    Toll-like receptors (TLRs) are crucial in innate recognition of invading micro-organisms and their subsequent clearance. Bacteria are not passive bystanders and have evolved complex evasion mechanisms. Staphylococcus aureus secretes a potent TLR2 antagonist, staphylococcal superantigen-like protein 3 (SSL3), which prevents receptor stimulation by pathogen-associated lipopeptides. Here, we present crystal structures of SSL3 and its complex with TLR2. The structure reveals that formation of the specific inhibitory complex is predominantly mediated by hydrophobic contacts between SSL3 and TLR2 and does not involve interaction of TLR2–glycans with the conserved LewisX binding site of SSL3. In the complex, SSL3 partially covers the entrance to the lipopeptide binding pocket in TLR2, reducing its size by ∼50%. We show that this is sufficient to inhibit binding of agonist Pam2CSK4 effectively, yet allows SSL3 to bind to an already formed TLR2–Pam2CSK4 complex. The binding site of SSL3 overlaps those of TLR2 dimerization partners TLR1 and TLR6 extensively. Combined, our data reveal a robust dual mechanism in which SSL3 interferes with TLR2 activation at two stages: by binding to TLR2, it blocks ligand binding and thus inhibits activation. Second, by interacting with an already formed TLR2–lipopeptide complex, it prevents TLR heterodimerization and downstream signaling. PMID:26283364

  7. [Description of a staphylococcal alimentary poisoning outbreak in Las Rosas, Santa Fe Province, Argentina].

    PubMed

    Brizzio, Aníbal A; Tedeschi, Fabián A; Zalazar, Fabián E

    2011-01-01

    On February 2008, a suspected foodborne outbreak was reported in Las Rosas (Santa Fe Province, Argentina). The formal procedures indicated that an undetermined number of individuals had experienced food poisoning following consumption of vegetable cannelloni bought at a local shop. The manufacturer establishment was audited. Samples from the suspected food, as well as environmental samples and swabs from food handlers were obtained and involved subjects were interviewed. Remnants of ingested food were also obtained. Routine microbiological procedures of the foodborne outbreak revealed the presence of coagulase positive S. aureus subspecies aureus in samples from ingested and raw food, and from manipulators. Indicator microorganisms did not show significant levels and no other foodborne pathogen was isolated. Presence of staphylococcal enterotoxin-producing genes was subsequently investigated, and a positive result for enterotoxin B was shown in S. aureus strains isolated from a food handler as well as from food linked to the outbreak Moreover, these isolates showed 100% similarity by SmaI-PFGE. Timely notification together with coordinated sanitary measures and the availability of appropriate laboratory tools allowed to interrupt the chain of disease transmission by identifying risk and protective factors. PMID:21491063

  8. Lysostaphin expression in mammary glands confers protection against staphylococcal infection in transgenic mice.

    PubMed

    Kerr, D E; Plaut, K; Bramley, A J; Williamson, C M; Lax, A J; Moore, K; Wells, K D; Wall, R J

    2001-01-01

    Infection of the mammary gland, in addition to causing animal distress, is a major economic burden of the dairy industry. Staphylococcus aureus is the major contagious mastitis pathogen, accounting for approximately 15-30% of infections, and has proved difficult to control using standard management practices. As a first step toward enhancing mastitis resistance of dairy animals, we report the generation of transgenic mice that secrete a potent anti-staphylococcal protein into milk. The protein, lysostaphin, is a peptidoglycan hydrolase normally produced by Staphylococcus simulans. When the native form is secreted by transfected eukaryotic cells it becomes glycosylated and inactive. However, removal of two glycosylation motifs through engineering asparagine to glutamine codon substitutions enables secretion of Gln(125,232)-lysostaphin, a bioactive variant. Three lines of transgenic mice, in which the 5'-flanking region of the ovine beta-lactoglobulin gene directed the secretion of Gln(125,232)-lysostaphin into milk, exhibit substantial resistance to an intramammary challenge of 104 colony-forming units (c.f.u.) of S. aureus, with the highest expressing line being completely resistant. Milk protein content and profiles of transgenic and nontransgenic mice are similar. These results clearly demonstrate the potential of genetic engineering to combat the most prevalent disease of dairy cattle.

  9. [Description of a staphylococcal alimentary poisoning outbreak in Las Rosas, Santa Fe Province, Argentina].

    PubMed

    Brizzio, Aníbal A; Tedeschi, Fabián A; Zalazar, Fabián E

    2011-01-01

    On February 2008, a suspected foodborne outbreak was reported in Las Rosas (Santa Fe Province, Argentina). The formal procedures indicated that an undetermined number of individuals had experienced food poisoning following consumption of vegetable cannelloni bought at a local shop. The manufacturer establishment was audited. Samples from the suspected food, as well as environmental samples and swabs from food handlers were obtained and involved subjects were interviewed. Remnants of ingested food were also obtained. Routine microbiological procedures of the foodborne outbreak revealed the presence of coagulase positive S. aureus subspecies aureus in samples from ingested and raw food, and from manipulators. Indicator microorganisms did not show significant levels and no other foodborne pathogen was isolated. Presence of staphylococcal enterotoxin-producing genes was subsequently investigated, and a positive result for enterotoxin B was shown in S. aureus strains isolated from a food handler as well as from food linked to the outbreak Moreover, these isolates showed 100% similarity by SmaI-PFGE. Timely notification together with coordinated sanitary measures and the availability of appropriate laboratory tools allowed to interrupt the chain of disease transmission by identifying risk and protective factors.

  10. Investigating an outbreak of staphylococcal food poisoning among travellers across two Australian states.

    PubMed Central

    Boonwaat, Leng; Moore, Terry; Chavada, Ruchir; Conaty, Stephen

    2015-01-01

    Introduction Staphylococcus aureus is a common cause of staphylococcal food poisoning in Australia with several outbreaks associated with foods prepared by commercial caterers. Laboratory testing on cases of gastrointestinal illness caused by enterotoxin-producing S. aureus is not routinely done as this condition is self-limiting. Hence outbreaks of such illness may go undetected. Methods A retrospective cohort study was conducted among a group of tourists who were hospitalized in Sydney shortly after flying from Queensland. The group had consumed food prepared by a restaurant on the Gold Coast before transit. Laboratory analyses on stool specimens were conducted in Sydney. An environmental assessment of the restaurant in the Gold Coast was conducted, and environmental specimens were assessed for contamination. Results Epidemiological investigations linked the outbreak to a restaurant in the Gold Coast where the suspected food was produced. Stool samples from two of the hospitalized cases were confirmed to have enterotoxin-producing S. aureus, and several environmental samples were found to be contaminated with S. aureus as well. Investigations suggested that absence of hand washing and other unhygienic food handling at the implicated restaurant was the likely cause of this outbreak. Conclusion Food poisoning due to toxin-mediated S. aureus is frequently undetected and underreported. Public health units should consider toxin-producing pathogens such as S. aureus when investigating outbreaks where vomiting is the predominant symptom and occurs rapidly after consuming food. PMID:26306211

  11. The human fibrinolytic system is a target for the staphylococcal metalloprotease aureolysin.

    PubMed

    Beaufort, Nathalie; Wojciechowski, Piotr; Sommerhoff, Christian P; Szmyd, Grzegorz; Dubin, Grzegorz; Eick, Sigrun; Kellermann, Josef; Schmitt, Manfred; Potempa, Jan; Magdolen, Viktor

    2008-02-15

    The major opportunistic pathogen Staphylococcus aureus utilizes the human fibrinolytic system for invasion and spread via plasmin(ogen) binding and non-proteolytic activation. Because S. aureus secretes several proteases recently proposed as virulence factors, we explored whether these enzymes could add to the activation of the host's fibrinolytic system. Exposure of human pro-urokinase [pro-uPA (where uPA is urokinase-type plasminogen activator)] to conditioned growth media from staphylococcal reference strains results in an EDTA-sensitive conversion of the single-chain zymogen into its two-chain active form, an activity not observed in an aureolysin-deficient strain. Using purified aureolysin, we verified the capacity of this thermolysin-like metalloprotease to activate pro-uPA, with a 2.6 x 10(3) M(-1) x s(-1) catalytic efficiency. Moreover, activation also occurs in the presence of human plasma, as well as in conditioned growth media from clinical isolates. Finally, we establish that aureolysin (i) converts plasminogen into angiostatin and mini-plasminogen, the latter retaining its capacity to be activated by uPA and to hydrolyse fibrin, (ii) degrades the plasminogen activator inhibitor-1, and (iii) abrogates the inhibitory activity of alpha(2)-antiplasmin. Altogether, we propose that, in parallel with the staphylokinase-dependent activation of plasminogen, aureolysin may contribute significantly to the activation of the fibrinolytic system by S. aureus, and thus may promote bacterial spread and invasion.

  12. Characterization of the staphylococcal beta-lactamase transposon Tn552.

    PubMed Central

    Rowland, S J; Dyke, K G

    1989-01-01

    The staphylococcal beta-lactamase transposon Tn552 is a member of a novel group of transposable elements. The organization of genes in Tn552 resembles that of members of the Tn21 sub-group of Tn3 family transposons, which transpose replicatively by cointegrate formation and resolution. Thus, a possible resolution site ('resL') and a resolvase gene (tnpR or 'binL') have been identified. However, consistent with the fact that Tn552 generates 6 bp (rather than 5 bp) flanking direct repeats of target DNA, neither the putative transposase protein, nor the terminal inverted repeats of Tn552 are homologous to those of Tn3 elements. Tn552, like phage Mu and retroelements, is defined by the terminal dinucleotides 5' TG .. CA 3'. A naturally occurring staphylococcal plasmid, pI9789, contains a Tn552-derived resolution system ('resR-binR') that acts as a 'hotspot' for Tn552 transposition; insertion creates a segment of DNA flanked by inversely repeated resolution sites, one (resR) on pI9789 and the other (resL) on Tn552. The putative Tn552 resolvase, the most closely related of known resolvases to the homologous DNA invertases, initially was identified as a DNA invertase ('Bin') as a result of its ability to mediate efficient inversion of this segment in vivo. PMID:2555186

  13. Defining species boundaries in the genus Phytophthora: the case of Phytophthora andina. A response to “Phytophthora andina sp. nov., a newly identified heterothallic pathogen of solanaceous hosts in the Andean highlands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The newly described species Phytophthora andina is a relative of the potato late blight pathogen P. infestans. The formal P. andina species description is based on three types of evidence. First, the fact that these Ecuadorian isolates were found causing disease on different wild Solanum spp. that a...

  14. Further evidence for staphylococcal food poisoning outbreaks caused by egc-encoded enterotoxins.

    PubMed

    Johler, Sophia; Giannini, Petra; Jermini, Marco; Hummerjohann, Jörg; Baumgartner, Andreas; Stephan, Roger

    2015-03-20

    Staphylococcal food poisoning represents the most prevalent foodborne intoxication worldwide. It is caused by oral intake of enterotoxins preformed by Staphylococcus aureus in food. The relevance of newly described enterotoxins in outbreaks of staphylococcal food poisoning is controversially discussed. Although the staphylococcal enterotoxins SEG, SEI, SEM, SEN, and SEO elicit emesis in a monkey feeding assay, there has been no conclusive proof of their emetic activity in humans. In this study, we provide further evidence suggesting that one of these enterotoxins or a combination of SEG, SEI, SEM, SEN, and SEO cause staphylococcal food poisoning. We investigated two outbreaks registered with the Swiss Federal Office of Public Health, in which only Staphylococcus aureus strains harboring the egc cluster, including seg, sei, sem, sen, and seo linked to typical signs of staphylococcal food poisoning were isolated. The outbreaks were caused by consumption of raw goat cheese and semi-hard goat cheese, and were linked to strains assigned to CC45 (agr type I) and CC9 (agr type II), respectively. These outbreaks provide further evidence that newly-described staphylococcal enterotoxins are likely to cause staphylococcal food poisoning in humans.

  15. Experimental challenge and pathology of highly pathogenic avian influenza virus H5N1 in dunlin (Calidris alpina), an intercontinental migrant shorebird species

    PubMed Central

    Hall, Jeffrey S.; Franson, J. Christian; Gill, Robert E.; Meteyer, Carol U.; TeSlaa, Joshua L.; Nashold, Sean; Dusek, Robert J.; Ip, Hon S.

    2011-01-01

    Please cite this paper as: Hall et al. (2011). Experimental challenge and pathology of highly pathogenic avian influenza virus H5N1 in dunlin (Calidris alpina), an intercontinental migrant shorebird species. Influenza and Other Respiratory Viruses 5(5), 365–372. Background  Shorebirds (Charadriiformes) are considered one of the primary reservoirs of avian influenza. Because these species are highly migratory, there is concern that infected shorebirds may be a mechanism by which highly pathogenic avian influenza virus (HPAIV) H5N1 could be introduced into North America from Asia. Large numbers of dunlin (Calidris alpina) migrate from wintering areas in central and eastern Asia, where HPAIV H5N1 is endemic, across the Bering Sea to breeding areas in Alaska. Low pathogenic avian influenza virus has been previously detected in dunlin, and thus, dunlin represent a potential risk to transport HPAIV to North America. To date no experimental challenge studies have been performed in shorebirds. Methods  Wild dunlin were inoculated intranasally and intrachoanally various doses of HPAIV H5N1. The birds were monitored daily for virus excretion, disease signs, morbidity, and mortality. Results  The infectious dose of HPAIV H5N1 in dunlin was determined to be 101.7 EID50/100 μl and that the lethal dose was 101.83 EID50/100 μl. Clinical signs were consistent with neurotropic disease, and histochemical analyses revealed that infection was systemic with viral antigen and RNA most consistently found in brain tissues. Infected birds excreted relatively large amounts of virus orally (104 EID50) and smaller amounts cloacally. Conclusions  Dunlin are highly susceptible to infection with HPAIV H5N1. They become infected after exposure to relatively small doses of the virus and if they become infected, they are most likely to suffer mortality within 3–5 days. These results have important implications regarding the risks of transport and transmission of HPAIV H5N1 to North

  16. Outbreak of staphylococcal food intoxication after consumption of pasteurized milk products, June 2007, Austria.

    PubMed

    Schmid, Daniela; Fretz, Rainer; Winter, Petra; Mann, Michaela; Höger, Gerda; Stöger, Anna; Ruppitsch, Werner; Ladstätter, Johann; Mayer, Norbert; de Martin, Alfred; Allerberger, Franz

    2009-01-01

    On June 13, 2007, the public health authority informed the Austrian Agency for Health and Food Safety about 40 children from two neighboring elementary schools who had fallen ill with abdominal cramps and vomiting on June 8. School milk products consumed on June 8 were suspected as the source of the outbreak. On June 8, the milk products provided by local dairy X to eight elementary schools and two nurseries. The short incubation period - all cases fell ill on the day on which the products were consumed - and the short duration of illness (1-2 days) strongly suggested intoxication. In order to identify the causative pathogen, its reservoir and the mode of transmission, a descriptive-epidemiological and microbiological investigation and a retrospective cohort study were conducted. Six of the 10 institutions served by dairy X completed questionnaires on demographics and food consumption. One school had a 79% response rate (203/258) and was chosen as the basis for our cohort study. A total of 166 of the 1025 children (16.2%) at the 10 institutions fulfilled the case definition. Consumption of milk, cacao milk or vanilla milk originating from dairy X was associated with a 37.8 times higher risk of becoming a case (95% CI: 2.3-116.5). Unopened milk products left over at the affected institutions yielded staphylococcal enterotoxins A and D. Six out of 64 quarter milk samples from three of 16 cows producing milk for dairy X tested positive for S. aureus. The isolates produced enterotoxins A and D, yielded genes encoding enterotoxins and D, and showed spa type t2953. S. aureus isolated from the nasal swab of the dairy owner harbored genes encoding enterotoxins C, G, H and I, and showed spa type t635. Our investigation revealed that the milk products produced in dairy X on June 7 were the source of the outbreak on June 8. The cows - not the dairy owner - the likely reservoir of the enterotoxin-producing S. aureus. From the risk assessment of the production process at the

  17. Stx-Producing Shigella Species From Patients in Haiti: An Emerging Pathogen With the Potential for Global Spread.

    PubMed

    Gray, Miranda D; Leonard, Susan R; Lacher, David W; Lampel, Keith A; Alam, Meer T; Morris, J Glenn; Ali, Afsar; LaBreck, Patrick T; Maurelli, Anthony T

    2015-12-01

    Shiga toxins (Stx) are commonly produced by Shigella dysenteriae serotype 1 and Stx-producing Escherichia coli. However, the toxin genes have been detected in additional Shigella species. We recently reported the emergence of Stx-producing Shigella in travelers in the United States and France who had recently visited Hispaniola (Haiti and the Dominican Republic). In this study, we confirm this epidemiological link by identifying Stx-producing Shigella from Haitian patients attending clinics near Port-au-Prince. We also demonstrate that the bacteriophage encoding Stx is capable of dissemination to stx-negative Shigella species found in Haiti, suggesting that Stx-producing Shigella may become more widespread within that region.

  18. Extracellular vesicles from Paracoccidioides pathogenic species transport polysaccharide and expose ligands for DC-SIGN receptors

    SciTech Connect

    da Silva, Roberta Peres; Heiss, Christian; Black, Ian; Azadi, Parastoo; Gerlach, Jared Q.; Travassos, Luiz R.; Joshi, Lokesh; Kilcoyne, Michelle; Puccia, Rosana

    2015-09-21

    Extracellular vesicles (EVs) mediate non-conventional transport of molecules across the fungal cell wall. We aimed at describing the carbohydrate composition and surface carbohydrate epitopes of EVs isolated from the pathogenic fungi Paracoccidioides brasiliensis and P. lutzii using standard procedures. Total EV carbohydrates were ethanol-precipitated from preparations depleted of lipids and proteins, then analyzed by chemical degradation, gas chromatography-mass spectrometry, nuclear magnetic resonance and size-exclusion chromatography. EV glycosyl residues of Glc, Man, and Gal comprised most probably two major components: a high molecular mass 4,6-α-glucan and a galactofuranosylmannan, possibly an oligomer, bearing a 2-α-Manp main chain linked to β-Galf (1,3) and α-Manp (1,6) end units. The results also suggested the presence of small amounts of a (1→6)- Manp polymer, (1→3)-glucan and (1→6)-glucan. Glycan microarrays allowed identification of EV surface lectin(s), while plant lectin microarray profiling revealed terminal Man and GlcNAc residues exposed at the EVs surface. Mammalian lectin microarray profiling showed that DC-SIGN receptors recognized surface carbohydrate in Paracoccidioides EVs. Our results suggest that oligosaccharides, cytoplasmic storage, and cell wall polysaccharides can be exported in fungal EVs, which also expose surface PAMPs and lectins. As a result, the role of these newly identified components in the interaction with the host remains to be unraveled.

  19. Pathogenicity of Two Species of Entomopathogenic Nematodes Against the Greenhouse Whitefly, Trialeurodes vaporariorum (Hemiptera: Aleyrodidae), in Laboratory and Greenhouse Experiments.

    PubMed

    Rezaei, Nastaran; Karimi, Javad; Hosseini, Mojtaba; Goldani, Morteza; Campos-Herrera, Raquel

    2015-03-01

    The greenhouse whitefly Trialeurodes vaporariorum (Hemiptera: Aleyrodidae) is a polyphagous pest in greenhouse crops. The efficacy of two entomopathogenic nematodes (EPN), Steinernema feltiae and Heterorhabditis bacteriophora, as biological control agents against T. vaporariorum was evaluated using two model crops typical of vegetable greenhouse productions: cucumber and pepper. Laboratory tests evaluated adults and second nymphal instars for pest susceptibility to different EPN species at different concentrations of infective juveniles (IJ; 0, 25, 50, 100, 150, 200, and 250 IJ per cm(2)); subsequent greenhouse trials against second nymphal instars on cucumber and pepper plants evaluated more natural conditions. Concentrations were applied in combination with Triton X-100 (0.1% v/v), an adjuvant for increasing nematode activity. In laboratory studies, both life stages were susceptible to infection by the two nematode species, but S. feltiae recorded a lower LC50 than H. bacteriophora for both insect stages. Similarly, in greenhouse experiments, S. feltiae required lower concentrations of IJ than H. bacteriophora to reach the same mortality in nymphs. In greenhouse trials, a significant difference was observed in the triple interaction among nematode species × concentration × plant. Furthermore, the highest mortality rate of the second nymphal instars of the T. vaporariorum was obtained from the application of S. feltiae concentrated to 250 IJ/cm(2) on cucumber (49 ± 1.23%). The general mortality caused by nematodes was significantly higher in cucumber than in pepper. These promising results support further investigation for the optimization of the best EPN species/concentration in combination with insecticides or adjuvants to reach a profitable control of this greenhouse pest.

  20. Pathogenicity of Two Species of Entomopathogenic Nematodes Against the Greenhouse Whitefly, Trialeurodes vaporariorum (Hemiptera: Aleyrodidae), in Laboratory and Greenhouse Experiments

    PubMed Central

    Rezaei, Nastaran; Karimi, Javad; Hosseini, Mojtaba; Goldani, Morteza; Campos-Herrera, Raquel

    2015-01-01

    The greenhouse whitefly Trialeurodes vaporariorum (Hemiptera: Aleyrodidae) is a polyphagous pest in greenhouse crops. The efficacy of two entomopathogenic nematodes (EPN), Steinernema feltiae and Heterorhabditis bacteriophora, as biological control agents against T. vaporariorum was evaluated using two model crops typical of vegetable greenhouse productions: cucumber and pepper. Laboratory tests evaluated adults and second nymphal instars for pest susceptibility to different EPN species at different concentrations of infective juveniles (IJ; 0, 25, 50, 100, 150, 200, and 250 IJ per cm2); subsequent greenhouse trials against second nymphal instars on cucumber and pepper plants evaluated more natural conditions. Concentrations were applied in combination with Triton X-100 (0.1% v/v), an adjuvant for increasing nematode activity. In laboratory studies, both life stages were susceptible to infection by the two nematode species, but S. feltiae recorded a lower LC50 than H. bacteriophora for both insect stages. Similarly, in greenhouse experiments, S. feltiae required lower concentrations of IJ than H. bacteriophora to reach the same mortality in nymphs. In greenhouse trials, a significant difference was observed in the triple interaction among nematode species × concentration × plant. Furthermore, the highest mortality rate of the second nymphal instars of the T. vaporariorum was obtained from the application of S. feltiae concentrated to 250 IJ/cm2 on cucumber (49 ± 1.23%). The general mortality caused by nematodes was significantly higher in cucumber than in pepper. These promising results support further investigation for the optimization of the best EPN species/concentration in combination with insecticides or adjuvants to reach a profitable control of this greenhouse pest. PMID:25861117

  1. Candida palmioleophila: characterization of a previously overlooked pathogen and its unique susceptibility profile in comparison with five related species.

    PubMed

    Jensen, Rasmus H; Arendrup, Maiken C

    2011-02-01

    Candida palmioleophila has previously been misidentified as C. famata or C. guilliermondii. We have investigated traditional and modern identification methods for the identification of this and related species. Forty-one clinical isolates previously identified as C. famata or C. guilliermondii and 8 reference strains were included. Color development on CHROMagar, growth temperature ranges, micromorphologies, carbon assimilation (ID32C), matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) profiles, and susceptibility profiles (mica- and anidulafungin and itra-, vori-, posa-, and fluconazole MICs were determined by EUCAST method EDef 7.1, and caspofungin MICs were determined by Etest) were determined, and results were compared to those of molecular identification (ITS1 and ITS2 sequencing). The following five different species were identified among the clinical isolates by sequencing, but no C. famata isolates were found: C. guilliermondii (22 isolates), C. palmioleophila (8 isolates), C. fermentati (6 isolates), C. lusitaniae (3 isolates), and C. intermedia (2 isolates). C. palmioleophila developed a distinct scintillating color of turquoise to rose, grew at 40°C, and failed to produce pseudohyphae within 14 days. The ID32C profile for 7/9 C. palmioleophila isolates was 5367352315, and all were unable to hydrolyze esculin (Esc). The six related species were well discriminated by MALDI-TOF MS. The susceptibility pattern for C. palmioleophila was unique, as the echinocandin MICs were low (range, 0.008 to 0.125 μg/ml) and fluconazole MICs were high (range, 8 to >16 μg/ml). Correct identification of C. palmioleophila is important due to its unique susceptibility profile. Identification is possible yet laborious with conventional techniques, whereas MALDI-TOF MS easily separated the related species.

  2. Candida palmioleophila: characterization of a previously overlooked pathogen and its unique susceptibility profile in comparison with five related species.

    PubMed

    Jensen, Rasmus H; Arendrup, Maiken C

    2011-02-01

    Candida palmioleophila has previously been misidentified as C. famata or C. guilliermondii. We have investigated traditional and modern identification methods for the identification of this and related species. Forty-one clinical isolates previously identified as C. famata or C. guilliermondii and 8 reference strains were included. Color development on CHROMagar, growth temperature ranges, micromorphologies, carbon assimilation (ID32C), matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) profiles, and susceptibility profiles (mica- and anidulafungin and itra-, vori-, posa-, and fluconazole MICs were determined by EUCAST method EDef 7.1, and caspofungin MICs were determined by Etest) were determined, and results were compared to those of molecular identification (ITS1 and ITS2 sequencing). The following five different species were identified among the clinical isolates by sequencing, but no C. famata isolates were found: C. guilliermondii (22 isolates), C. palmioleophila (8 isolates), C. fermentati (6 isolates), C. lusitaniae (3 isolates), and C. intermedia (2 isolates). C. palmioleophila developed a distinct scintillating color of turquoise to rose, grew at 40°C, and failed to produce pseudohyphae within 14 days. The ID32C profile for 7/9 C. palmioleophila isolates was 5367352315, and all were unable to hydrolyze esculin (Esc). The six related species were well discriminated by MALDI-TOF MS. The susceptibility pattern for C. palmioleophila was unique, as the echinocandin MICs were low (range, 0.008 to 0.125 μg/ml) and fluconazole MICs were high (range, 8 to >16 μg/ml). Correct identification of C. palmioleophila is important due to its unique susceptibility profile. Identification is possible yet laborious with conventional techniques, whereas MALDI-TOF MS easily separated the related species. PMID:21147953

  3. Biosecurity and Vector Behaviour: Evaluating the Potential Threat Posed by Anglers and Canoeists as Pathways for the Spread of Invasive Non-Native Species and Pathogens

    PubMed Central

    Anderson, Lucy G.; White, Piran C. L.; Stebbing, Paul D.; Stentiford, Grant D.; Dunn, Alison M.

    2014-01-01

    Invasive non-native species (INNS) endanger native biodiversity and are a major economic problem. The management of pathways to prevent their introduction and establishment is a key target in the Convention on Biological Diversity's Aichi biodiversity targets for 2020. Freshwater environments are particularly susceptible to invasions as they are exposed to multiple introduction pathways, including non-native fish stocking and the release of boat ballast water. Since many freshwater INNS and aquatic pathogens can survive for several days in damp environments, there is potential for transport between water catchments on the equipment used by recreational anglers and canoeists. To quantify this biosecurity risk, we conducted an online questionnaire with 960 anglers and 599 canoeists to investigate their locations of activity, equipment used, and how frequently equipment was cleaned and/or dried after use. Anglers were also asked about their use and disposal of live bait. Our results indicate that 64% of anglers and 78.5% of canoeists use their equipment/boat in more than one catchment within a fortnight, the survival time of many of the INNS and pathogens considered in this study and that 12% of anglers and 50% of canoeists do so without either cleaning or drying their kit between uses. Furthermore, 8% of anglers and 28% of canoeists had used their equipment overseas without cleaning or drying it after each use which could facilitate both the introduction and secondary spread of INNS in the UK. Our results provide a baseline against which to evaluate the effectiveness of future biosecurity awareness campaigns, and identify groups to target with biosecurity awareness information. Our results also indicate that the biosecurity practices of these groups must improve to reduce the likelihood of inadvertently spreading INNS and pathogens through these activities. PMID:24717714

  4. Elucidating the Diversity of Aquatic Microdochium and Trichoderma Species and Their Activity against the Fish Pathogen Saprolegnia diclina

    PubMed Central

    Liu, Yiying; Zachow, Christin; Raaijmakers, Jos M.; de Bruijn, Irene

    2016-01-01

    Animals and plants are increasingly threatened by emerging fungal and oomycete diseases. Amongst oomycetes, Saprolegnia species cause population declines in aquatic animals, especially fish and amphibians, resulting in significant perturbation in biodiversity, ecological balance and food security. Due to the prohibition of several chemical control agents, novel sustainable measures are required to control Saprolegnia infections in aquaculture. Previously, fungal community analysis by terminal restriction fragment length polymorphism (T-RFLP) revealed that the Ascomycota, specifically the genus Microdochium, was an abundant fungal phylum associated with salmon eggs from a commercial fish farm. Here, phylogenetic analyses showed that most fungal isolates obtained from salmon eggs were closely related to Microdochium lycopodinum/Microdochium phragmitis and Trichoderma viride species. Phylogenetic and quantitative PCR analyses showed both a quantitative and qualitative difference in Trichoderma population between diseased and healthy salmon eggs, which was not the case for the Microdochium population. In vitro antagonistic activity of the fungi against Saprolegnia diclina was isolate-dependent; for most Trichoderma isolates, the typical mycoparasitic coiling around and/or formation of papilla-like structures on S. diclina hyphae were observed. These results suggest that among the fungal community associated with salmon eggs, Trichoderma species may play a role in Saprolegnia suppression in aquaculture. PMID:26805821

  5. Elucidating the Diversity of Aquatic Microdochium and Trichoderma Species and Their Activity against the Fish Pathogen Saprolegnia diclina.

    PubMed

    Liu, Yiying; Zachow, Christin; Raaijmakers, Jos M; de Bruijn, Irene

    2016-01-01

    Animals and plants are increasingly threatened by emerging fungal and oomycete diseases. Amongst oomycetes, Saprolegnia species cause population declines in aquatic animals, especially fish and amphibians, resulting in significant perturbation in biodiversity, ecological balance and food security. Due to the prohibition of several chemical control agents, novel sustainable measures are required to control Saprolegnia infections in aquaculture. Previously, fungal community analysis by terminal restriction fragment length polymorphism (T-RFLP) revealed that the Ascomycota, specifically the genus Microdochium, was an abundant fungal phylum associated with salmon eggs from a commercial fish farm. Here, phylogenetic analyses showed that most fungal isolates obtained from salmon eggs were closely related to Microdochium lycopodinum/Microdochium phragmitis and Trichoderma viride species. Phylogenetic and quantitative PCR analyses showed both a quantitative and qualitative difference in Trichoderma population between diseased and healthy salmon eggs, which was not the case for the Microdochium population. In vitro antagonistic activity of the fungi against Saprolegnia diclina was isolate-dependent; for most Trichoderma isolates, the typical mycoparasitic coiling around and/or formation of papilla-like structures on S. diclina hyphae were observed. These results suggest that among the fungal community associated with salmon eggs, Trichoderma species may play a role in Saprolegnia suppression in aquaculture. PMID:26805821

  6. Elucidating the Diversity of Aquatic Microdochium and Trichoderma Species and Their Activity against the Fish Pathogen Saprolegnia diclina.

    PubMed

    Liu, Yiying; Zachow, Christin; Raaijmakers, Jos M; de Bruijn, Irene

    2016-01-21

    Animals and plants are increasingly threatened by emerging fungal and oomycete diseases. Amongst oomycetes, Saprolegnia species cause population declines in aquatic animals, especially fish and amphibians, resulting in significant perturbation in biodiversity, ecological balance and food security. Due to the prohibition of several chemical control agents, novel sustainable measures are required to control Saprolegnia infections in aquaculture. Previously, fungal community analysis by terminal restriction fragment length polymorphism (T-RFLP) revealed that the Ascomycota, specifically the genus Microdochium, was an abundant fungal phylum associated with salmon eggs from a commercial fish farm. Here, phylogenetic analyses showed that most fungal isolates obtained from salmon eggs were closely related to Microdochium lycopodinum/Microdochium phragmitis and Trichoderma viride species. Phylogenetic and quantitative PCR analyses showed both a quantitative and qualitative difference in Trichoderma population between diseased and healthy salmon eggs, which was not the case for the Microdochium population. In vitro antagonistic activity of the fungi against Saprolegnia diclina was isolate-dependent; for most Trichoderma isolates, the typical mycoparasitic coiling around and/or formation of papilla-like structures on S. diclina hyphae were observed. These results suggest that among the fungal community associated with salmon eggs, Trichoderma species may play a role in Saprolegnia suppression in aquaculture.

  7. VraH Is the Third Component of the Staphylococcus aureus VraDEH System Involved in Gallidermin and Daptomycin Resistance and Pathogenicity

    PubMed Central

    Popella, Peter; Krauss, Sophia; Ebner, Patrick; Nega, Mulugeta; Deibert, Julia

    2016-01-01

    In bacteria, extracellular signals are transduced into the cell predominantly by two-component systems (TCSs) comprising a regulatory unit triggered by a specific signal. Some of the TCSs control executing units such as ABC transporters involved in antibiotic resistance. For instance, in Staphylococcus aureus, activation of BraSR leads to the upregulation of vraDE expression that encodes an ABC transporter playing a role in bacitracin and nisin resistance. In this study, we show that the small staphylococcal transmembrane protein VraH forms, together with VraDE, a three-component system. Although the expression of vraH in the absence of vraDE was sufficient to mediate low-level resistance, only this VraDEH entity conferred high-level resistance against daptomycin and gallidermin. In most staphylococcal genomes, vraH is located immediately downstream of vraDE, forming an operon, whereas in some species it is localized differently. In an invertebrate infection model, VraDEH significantly enhanced S. aureus pathogenicity. In analogy to the TCS connectors, VraH can be regarded as an ABC connector that modulates the activity of ABC transporters involved in antibiotic resistance. PMID:26856834

  8. Nitric oxide and reactive oxygen species regulate the accumulation of heat shock proteins in tomato leaves in response to heat shock and pathogen infection.

    PubMed

    Piterková, Jana; Luhová, Lenka; Mieslerová, Barbora; Lebeda, Aleš; Petřivalský, Marek

    2013-06-01

    Heat shock proteins (HSP) are produced in response to various stress stimuli to prevent cell damage. We evaluated the involvement of nitric oxide (NO) and reactive oxygen species (ROS) in the accumulation of Hsp70 proteins in tomato leaves induced by abiotic and biotic stress stimuli. A model system of leaf discs was used with two tomato genotypes, Solanum lycopersicum cv. Amateur and Solanum chmielewskii, differing in their resistance to fungal pathogen Oidium neolycopersici. Leaf discs were exposed to stress factors as heat shock and pathogen infection alone or in a combination, and treated with substances modulating endogenous NO and ROS levels. Two proteins of Hsp70 family were detected in stressed tomato leaf discs: a heat-inducible 72 kDa protein and a constitutive 75 kDa protein. The pathogenesis and mechanical stress influenced Hsp75 accumulation, whereas heat stress induced mainly Hsp72 production. Treatment with NO donor and NO scavenger significantly modulated the level of Hsp70 in variable manner related to the genotype resistance. Hsp70 accumulation correlated with endogenous NO level in S. lycopersicum and ROS levels in S. chmielewskii. We conclude NO and ROS are involved in the regulation of Hsp70 production and accumulation under abiotic and biotic stresses in dependence on plant ability to trigger its defence mechanisms. PMID:23602099

  9. The Immune Strategy and Stress Response of the Mediterranean Species of the Bemisia tabaci Complex to an Orally Delivered Bacterial Pathogen

    PubMed Central

    Xia, Jun; Li, Fang-Fang; Xia, Wen-Qiang; Liu, Shu-Sheng; Wang, Xiao-Wei

    2014-01-01

    Background The whitefly, Bemisia tabaci, a notorious agricultural pest, has complex relationships with diverse microbes. The interactions of the whitefly with entomopathogens as well as its endosymbionts have received great attention, because of their potential importance in developing novel whitefly control technologies. To this end, a comprehensive understanding on the whitefly defense system is needed to further decipher those interactions. Methodology/Principal Findings We conducted a comprehensive investigation of the whitefly's defense responses to infection, via oral ingestion, of the pathogen, Pseudomonas aeruginosa, using RNA-seq technology. Compared to uninfected whiteflies, 6 and 24 hours post-infected whiteflies showed 1,348 and 1,888 differentially expressed genes, respectively. Functional analysis of the differentially expressed genes revealed that the mitogen associated protein kinase (MAPK) pathway was activated after P. aeruginosa infection. Three knottin-like antimicrobial peptide genes and several components of the humoral and cellular immune responses were also activated, indicating that key immune elements recognized in other insect species are also important for the response of B. tabaci to pathogens. Our data also suggest that intestinal stem cell mediated epithelium renewal might be an important component of the whitefly's defense against oral bacterial infection. In addition, we show stress responses to be an essential component of the defense system. Conclusions/Significance We identified for the first time the key immune-response elements utilized by B. tabaci against bacterial infection. This study provides a framework for future research into the complex interactions between whiteflies and microbes. PMID:24722540

  10. Cross-species induction of antimicrobial compounds, biosurfactants and quorum-sensing inhibitors in tropical marine epibiotic bacteria by pathogens and biofouling microorganisms.

    PubMed

    Dusane, Devendra H; Matkar, Pratiek; Venugopalan, Valayam P; Kumar, Ameeta Ravi; Zinjarde, Smita S

    2011-03-01

    Enhancement or induction of antimicrobial, biosurfactant, and quorum-sensing inhibition property in marine bacteria due to cross-species and cross-genera interactions was investigated. Four marine epibiotic bacteria (Bacillus sp. S3, B. pumilus S8, B. licheniformis D1, and Serratia marcescens V1) displaying antimicrobial activity against pathogenic or biofouling fungi (Candida albicans CA and Yarrowia lipolytica YL), and bacteria (Pseudomonas aeruginosa PA and Bacillus pumilus BP) were chosen for this study. The marine epibiotic bacteria when co-cultivated with the aforementioned fungi or bacteria showed induction or enhancement in antimicrobial activity, biosurfactant production, and quorum-sensing inhibition. Antifungal activity against Y. lipolytica YL was induced by co-cultivation of the pathogens or biofouling strains with the marine Bacillus sp. S3, B. pumilus S8, or B. licheniformis D1. Antibacterial activity against Ps. aeruginosa PA or B. pumilus BP was enhanced in most of the marine isolates after co-cultivation. Biosurfactant activity was significantly increased when cells of B. pumilus BP were co-cultivated with S. marcescens V1, B. pumilus S8, or B. licheniformis D1. Pigment reduction in the quorum-sensing inhibition indicator strain Chromobacterium violaceum 12472 was evident when the marine strain of Bacillus sp. S3 was grown in the presence of the inducer strain Ps. aeruginosa PA, suggesting quorum-sensing inhibition. The study has important ecological and biotechnological implications in terms of microbial competition in natural environments and enhancement of secondary metabolite production.

  11. Cloning, expression, and mutagenesis of phosphatidylinositol-specific phospholipase C from Staphylococcus aureus: a potential staphylococcal virulence factor.

    PubMed Central

    Daugherty, S; Low, M G

    1993-01-01

    Staphylococcus aureus secretes a phosphatidylinositol (PI)-specific phospholipase C (PI-PLC) which is able to hydrolyze the membrane lipid PI and membrane protein anchors containing glycosyl-PI. The gene for PI-PLC (plc) was cloned from S. aureus into Escherichia coli. Oligonucleotide probes based on partial protein sequence and polyclonal antibodies raised against the purified protein were used to identify positive clones. E. coli transformed with a plasmid containing the plc gene expressed PI-PLC enzyme activity which was abolished by mutagenesis with a tetracycline resistance gene. The plc gene was present in all 15 S. aureus strains examined but not in any of 6 coagulase-negative staphylococcal species. The plc gene contained 984 bp and coded for a mature protein with a calculated molecular mass of 34,107 Da. Amino acid sequence comparisons indicated that the staphylococcal plc gene was similar (51 to 56%) to the PI-PLCs from Bacillus cereus, Bacillus thuringiensis, and Listeria monocytogenes. The recombinant PI-PLC expressed in E. coli was purified and exhibited biochemical properties identical to those of the native PI-PLC from S. aureus. PI-PLC production was decreased in agr mutant strains of S. aureus. However, PI-PLC production by both agr+ and agr mutant strains exhibited a similar dependence on the type of medium used. These data suggested that PI-PLC production was regulated by both agr-dependent and agr-independent mechanisms. Images PMID:8225585

  12. Volatiles Emitted from Maize Ears Simultaneously Infected with Two Fusarium Species Mirror the Most Competitive Fungal Pathogen

    PubMed Central

    Sherif, Mohammed; Becker, Eva-Maria; Herrfurth, Cornelia; Feussner, Ivo; Karlovsky, Petr; Splivallo, Richard

    2016-01-01

    Along with barley and rice, maize provides staple food for more than half of the world population. Maize ears are regularly infected with fungal pathogens of the Fusarium genus, which, besides reducing yield, also taint grains with toxic metabolites. In an earlier work, we have shown that maize ears infection with single Fusarium strains was detectable through volatile sensing. In nature, infection most commonly occurs with more than a single fungal strain; hence we tested how the interactions of two strains would modulate volatile emission from infected ears. For this purpose, ears of a hybrid and a dwarf maize variety were simultaneously infected with different strains of Fusarium graminearum and F. verticillioides and, the resulting volatile profiles were compared to the ones of ears infected with single strains. Disease severity, fungal biomass, and the concentration of the oxylipin 9-hydroxy octadecadienoic acid, a signaling molecule involved in plant defense, were monitored and correlated to volatile profiles. Our results demonstrate that in simultaneous infections of hybrid and dwarf maize, the most competitive fungal strains had the largest influence on the volatile profile of infected ears. In both concurrent and single inoculations, volatile profiles reflected disease severity. Additionally, the data further indicate that dwarf maize and hybrid maize might emit common (i.e., sesquiterpenoids) and specific markers upon fungal infection. Overall this suggests that volatile profiles might be a good proxy for disease severity regardless of the fungal competition taking place in maize ears. With the appropriate sensitivity and reliability, volatile sensing thus appears as a promising tool for detecting fungal infection of maize ears under field conditions. PMID:27729923

  13. Experimental challenge and pathology of highly pathogenic avian influenza virus H5N1 in dunlin (Calidris alpina), an intercontinental migrant shorebird species

    USGS Publications Warehouse

    Hall, J.S.; Franson, J.C.; Gill, R.E.; Meteyer, C.U.; Teslaa, J.L.; Nashold, S.; Dusek, R.J.; Ip, H.S.

    2011-01-01

    Background Shorebirds (Charadriiformes) are considered one of the primary reservoirs of avian influenza. Because these species are highly migratory, there is concern that infected shorebirds may be a mechanism by which highly pathogenic avian influenza virus (HPAIV) H5N1 could be introduced into North America from Asia. Large numbers of dunlin (Calidris alpina) migrate from wintering areas in central and eastern Asia, where HPAIV H5N1 is endemic, across the Bering Sea to breeding areas in Alaska. Low pathogenic avian influenza virus has been previously detected in dunlin, and thus, dunlin represent a potential risk to transport HPAIV to North America. To date no experimental challenge studies have been performed in shorebirds. Methods Wild dunlin were inoculated intranasally and intrachoanally various doses of HPAIV H5N1. The birds were monitored daily for virus excretion, disease signs, morbidity, and mortality. Results The infectious dose of HPAIV H5N1 in dunlin was determined to be 101.7 EID50/100 ??l and that the lethal dose was 101.83 EID50/100 ??l. Clinical signs were consistent with neurotropic disease, and histochemical analyses revealed that infection was systemic with viral antigen and RNA most consistently found in brain tissues. Infected birds excreted relatively large amounts of virus orally (104 EID50) and smaller amounts cloacally. Conclusions Dunlin are highly susceptible to infection with HPAIV H5N1. They become infected after exposure to relatively small doses of the virus and if they become infected, they are most likely to suffer mortality within 3-5days. These results have important implications regarding the risks of transport and transmission of HPAIV H5N1 to North America by this species and raises questions for further investigation. Published 2011. This article is a US Government work and is in the public domain in the USA.

  14. Identification in methicillin-susceptible Staphylococcus hominis of an active primordial mobile genetic element for the staphylococcal cassette chromosome mec of methicillin-resistant Staphylococcus aureus.

    PubMed

    Katayama, Yuki; Takeuchi, Fumihiko; Ito, Teruyo; Ma, Xiao Xue; Ui-Mizutani, Yoko; Kobayashi, Ichizo; Hiramatsu, Keiichi

    2003-05-01

    We previously reported that the methicillin resistance gene mecA is carried by a novel type of mobile genetic element, SCCmec (staphylococcal cassette chromosome mec), in the chromosome of methicillin-resistant Staphylococcus aureus (MRSA). These elements are precisely excised from the chromosome and integrated into a specific site on the recipient chromosome by a pair of recombinase proteins encoded by the cassette chromosome recombinase genes ccrA and ccrB. In the present work, we detected homologues of the ccr genes in Staphylococcus hominis type strain GIFU12263 (equivalent to ATCC 27844), which is susceptible to methicillin. Sequence determination revealed that the ccr homologues in S. hominis were type 1 ccr genes (ccrA1 and ccrB1) that were localized on a genetic element structurally very similar to SCCmec except for the absence of the methicillin-resistance gene, mecA. This genetic element had mosaic-like patterns of homology with extant SCCmec elements, and we designated it SCC(12263) and considered it a type I staphylococcal cassette chromosome (SCC). The ccrB1 gene identified in the S. hominis strain is the first type 1 ccrB gene discovered to retain its function through the excision process as judged by two criteria: (i) SCC(12263) was spontaneously excised during cultivation of the strain and (ii) introduction of the S. hominis ccrB1 into an MRSA strain carrying a type I SCCmec whose ccrB1 gene is inactive generated SCCmec excisants at a high frequency. The existence of an SCC without a mec determinant is indicative of a staphylococcal site-specific mobile genetic element that serves as a vehicle of transfer for various genetic markers between staphylococcal species.

  15. RNA-seq-Based Gene Annotation and Comparative Genomics of Four Fungal Grass Pathogens in the Genus Zymoseptoria Identify Novel Orphan Genes and Species-Specific Invasions of Transposable Elements.

    PubMed

    Grandaubert, Jonathan; Bhattacharyya, Amitava; Stukenbrock, Eva H

    2015-04-27

    The fungal pathogen Zymoseptoria tritici (synonym Mycosphaerella graminicola) is a prominent pathogen of wheat. The reference genome of the isolate IPO323 is one of the best-assembled eukaryotic genomes and encodes more than 10,000 predicted genes. However, a large proportion of the previously annotated gene models are incomplete, with either no start or no stop codons. The availability of RNA-seq data allows better predictions of gene structure. We here used two different RNA-seq datasets, de novo transcriptome assemblies, homology-based comparisons, and trained ab initio gene callers to generate a new gene annotation of Z. tritici IPO323. The annotation pipeline was also applied to re-sequenced genomes of three closely related species of Z. tritici: Z. pseudotritici, Z. ardabiliae, and Z. brevis. Comparative analyses of the predicted gene models using the four Zymoseptoria species revealed sets of species-specific orphan genes enriched with putative pathogenicity-related genes encoding small secreted proteins that may play essential roles in virulence and host specificity. De novo repeat identification allowed us to show that few families of transposable elements are shared between Zymoseptoria species while we observe many species-specific invasions and expansions. The annotation data presented here provide a high-quality resource for future studies of Z. tritici and its sister species and provide detailed insight into gene and genome evolution of fungal plant pathogens.

  16. [Clinical aspects of streptococcal and staphylococcal toxinic diseases].

    PubMed

    Floret, D

    2001-09-01

    Staphylococcus aureus and Streptococcus pyogenes produce a lot of toxins, some of them responsible for specific diseases. Staphylococcal food poisoning is due to ingestion of enterotoxin containing food. Seven toxins have been isolated so far. Generalized exfoliative syndrome is related to exfoliatin. Young children are particularly affected. The disease consists in a cutaneous exfoliation usually limited with a favourable outcome. The mucus membranes are not involved. The nose or pharynx are the most usual portal of entry. Staphylococcus aureus is not grown from the bullae. Severe extensive forms have been observed particularly in neonates (Ritter's disease). Bullous impetigo is also due to exfoliatin. It consists in the presence of a restricted number of cloudy bullae, from which staphylococcus can be grown. It is a mild disease with a favourable outcome within a few days. Scarlet fever is related to the streptococcal erythrogenic toxins. The classic form of the disease is presently rare. This disease may be related to staphylococcus as a complication of arthritis, osteomyelitis or wound super-infection. Bacteremia is usual. Staphylococcal scarlet fever is not related to exfoliatin as previously believed, but to enterotoxins or TSST-1, so it seems to be an abortive form of toxic shock syndrome. Toxic shock syndrome is defined as a multi organ failure syndrome with a rapid onset, fever, rash followed by desquamation, vomiting and diarrhea, hypotension, conjunctivitis and strawberry tongue. The disease is related to an infection or colonisation with a toxin (TSST-1) producing strain of Staphylococcus aureus. Enterotoxins (mainly C) may be involved. The disease may occur in childhood, sometimes after superinfection of varicella. The mortality is low (5%) and mainly due to ARDS or cardiac problems. Erythrogenic toxins produced by Streptococcus pyogenes are involved in a streptococcal form of toxic shock syndrome with a quite similar presentation. In most cases

  17. Effect of environment on staphylococcal lesions in mice.

    PubMed

    Schmidt, J P; Cordaro, J T; Ball, R J

    1967-11-01

    The influence of reduced barometric pressure on the development and healing of staphylococcal skin lesions in mice was investigated by exposing groups of animals to the test environment before, after, or before and after subcutaneous inoculation with 3.5 x 10 colony-forming units of a phage type 80 strain of Staphylococcus aureus. Similarly infected control animals were not exposed to the experimental environment. The results indicate that the lesions which developed in mice exposed to the test environment prior to infectious challenge were larger and healed at a slower rate than those in mice maintained at ground level before infection. Exposure after inoculation produced no demonstrable effect in the size or healing rate of the experimental lesions.

  18. Staphylococcal methicillin resistance: fine focus on folds and functions.

    PubMed

    Mallorquí-Fernández, Goretti; Marrero, Aniebrys; García-Piquè, Sonia; García-Castellanos, Raquel; Gomis-Rüth, F Xavier

    2004-06-01

    Globalisation has entailed a massive increase in trade and human mobility facilitating the rapid spread of infectious agents, including those that are drug resistant. A particularly serious threat to human health is posed by methicillin-resistant staphylococcal strains which have acquired molecular mechanisms to evade the action of beta-lactam antibiotics (BLAs). Full expression of high-level methicillin resistance involves a complex network of molecules and depends primarily on sufficient expression of a penicillin-binding protein with low sensitivity towards BLAs. Other factors include the fine-tuned regulation of autolytic activity of cell-wall components, as well as an optimal rate of peptidoglycan precursor formation and a highly specific peptidoglycan precursor structure. Three-dimensional structural data are available on several of the pieces involved in the jigsaw puzzle and provide a molecular basis for the understanding of methicillin resistance and for the design of new therapeutic strategies.

  19. Autoinducer-2 of Streptococcus mitis as a Target Molecule to Inhibit Pathogenic Multi-Species Biofilm Formation In Vitro and in an Endotracheal Intubation Rat Model

    PubMed Central

    Wang, Zhengli; Xiang, Qingqing; Yang, Ting; Li, Luquan; Yang, Jingli; Li, Hongong; He, Yu; Zhang, Yunhui; Lu, Qi; Yu, Jialin

    2016-01-01

    Streptococcus mitis (S. mitis) and Pseudomonas aeruginosa (P. aeruginosa) are typically found in the upper respiratory tract of infants. We previously found that P. aeruginosa and S. mitis were two of the most common bacteria in biofilms on newborns’ endotracheal tubes (ETTs) and in their sputa and that S. mitis was able to produce autoinducer-2 (AI-2), whereas P. aeruginosa was not. Recently, we also found that exogenous AI-2 and S. mitis could influence the behaviors of P. aeruginosa. We hypothesized that S. mitis contributes to this interspecies interaction and that inhibition of AI-2 could result in inhibition of these effects. To test this hypothesis, we selected PAO1 as a representative model strain of P. aeruginosa and evaluated the effect of S. mitis as well as an AI-2 analog (D-ribose) on mono- and co-culture biofilms in both in vitro and in vivo models. In this context, S. mitis promoted PAO1 biofilm formation and pathogenicity. Dual-species (PAO1 and S. mitis) biofilms exhibited higher expression of quorum sensing genes than single-species (PAO1) biofilms did. Additionally, ETTs covered in dual-species biofilms increased the mortality rate and aggravated lung infection compared with ETTs covered in mono-species biofilms in an endotracheal intubation rat model, all of which was inhibited by D-ribose. Our results demonstrated that S. mitis AI-2 plays an important role in interspecies interactions with PAO1 and may be a target for inhibition of biofilm formation and infection in ventilator-associated pneumonia. PMID:26903968

  20. Discrimination of selected species of pathogenic bacteria using near-infrared Raman spectroscopy and principal components analysis

    NASA Astrophysics Data System (ADS)

    de Siqueira e Oliveira, Fernanda S.; Giana, Hector E.; Silveira, Landulfo, Jr.

    2012-03-01

    It has been proposed a method based on Raman spectroscopy for identification of different microorganisms involved in bacterial urinary tract infections. Spectra were collected from different bacterial colonies (Gram negative: E. coli, K. pneumoniae, P. mirabilis, P. aeruginosa, E. cloacae and Gram positive: S. aureus and Enterococcus sp.), grown in culture medium (Agar), using a Raman spectrometer with a fiber Raman probe (830 nm). Colonies were scraped from Agar surface placed in an aluminum foil for Raman measurements. After pre-processing, spectra were submitted to a Principal Component Analysis and Mahalanobis distance (PCA/MD) discrimination algorithm. It has been found that the mean Raman spectra of different bacterial species show similar bands, being the S. aureus well characterized by strong bands related to carotenoids. PCA/MD could discriminate Gram positive bacteria with sensitivity and specificity of 100% and Gram negative bacteria with good sensitivity and high specificity.

  1. Discrimination of selected species of pathogenic bacteria using near-infrared Raman spectroscopy and principal components analysis

    NASA Astrophysics Data System (ADS)

    de Siqueira e Oliveira, Fernanda SantAna; Giana, Hector Enrique; Silveira, Landulfo

    2012-10-01

    A method, based on Raman spectroscopy, for identification of different microorganisms involved in bacterial urinary tract infections has been proposed. Spectra were collected from different bacterial colonies (Gram-negative: Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa and Enterobacter cloacae, and Gram-positive: Staphylococcus aureus and Enterococcus spp.), grown on culture medium (agar), using a Raman spectrometer with a fiber Raman probe (830 nm). Colonies were scraped from the agar surface and placed on an aluminum foil for Raman measurements. After preprocessing, spectra were submitted to a principal component analysis and Mahalanobis distance (PCA/MD) discrimination algorithm. We found that the mean Raman spectra of different bacterial species show similar bands, and S. aureus was well characterized by strong bands related to carotenoids. PCA/MD could discriminate Gram-positive bacteria with sensitivity and specificity of 100% and Gram-negative bacteria with sensitivity ranging from 58 to 88% and specificity ranging from 87% to 99%.

  2. Interaction between ticks (Acari: Ixodidae) and pathogenic nematodes (Nematoda): susceptibility of tick species at various developmental stages.

    PubMed

    Samish, M; Alekseev, E; Glazer, I

    1999-11-01

    The virulence of entomopathogenic nematodes (Steinernematidae and Heterorhabditidae) to tick species under laboratory conditions is reported. The susceptibility of larval, nymphal, and adult stages of the ticks Hyalomma excavatum (Koch), Rhipicephalus bursa (Canestrini & Fanz), and R. sanguineus (Latereille) to 2 strains of Steinernema carpocapsae and 3 strains of Heterorhabditis bacteriophora were compared in laboratory assays. Preimaginal stages of ticks were found to be more resistant to the nematodes than were adult ticks which exhibited 80-100% mortality in a dish containing 5,000 infective juveniles of H. bacteriophora IS-3 or IS-5 strains isolated in Israel. These 2 strains were found to be much more virulent to unfed adult ticks than were the other isolates. No marked difference was found between engorged ticks and unfed adults of R. sanguineus or H. excavatum in terms of mortality, whereas engorged males and unfed females of R. bursa were significantly more susceptible than unfed males or engorged females. PMID:10593074

  3. Molecular Screening of Staphylococcal Enterotoxin B Gene in Clinical Isolates

    PubMed Central

    Ataee, Ramezan Ali; Karami, Ali; Izadi, Morteza; Aghania, Aref; Ataee, Mohammad Hossein

    2011-01-01

    Objective: The role of staphylococcal enterotoxin B (SEB) in food poisoning is well known, however its role in other diseases remains to be explored. The aim of this study is the molecular screening and characterization of the SEB gene in clinically isolated strains. Materials and Methods: In this experimentally study, 300 Staphylococcus aureus (S. aureus) strains isolated from clinical samples were assayed. The isolated strains were confirmed by conventional bacteriological methods. Polymerase chain reaction (PCR) was used to determine the enterotoxin B (ent B) gene. Assessment of toxin production in all strains that contained the ent B gene was then performed. Finally, using specific antibody against SEB, a Western-blot was applied to confirm detection of enterotoxin B production. Results: Results indicated that only 5% of the 300 clinically isolated S. aureus contained the ent B gene. All strains which contained the ent B gene produced a proteinous enterotoxin B. The results of sequence determination of the PCR product were compared with the gene bank database and 98% similarity was achieved. The results of the Western-blot confirmed that enterotoxin B was produced in strains that contained the ent B gene. Conclusion: The results of this study indicate that 5% of clinically isolated S. aureus strains produce enterotoxin B. Considering that the enterotoxin B is an important superantigen, it is possible that a delay in diagnosis and lack of early proper treatment can cause an incidence of late complications, particularly in staphylococcal chronic infections. For this reason, it is suggested that in addition to detecting bacteria, an enterotoxin B detection test should be performed to control its toxigenicity. PMID:23508641

  4. Teichoic acid antibody test: its use in patients with coagulase-positive staphylococcal bacteremia.

    PubMed

    Larinkari, U M; Valtonen, M V; Sarvas, M; Valtonen, V V

    1977-11-01

    We have studied the occurrence and specificity of teichoic acid antibodies (TAAs), measured by double diffusion in agar, in 114 patients with bacteremia of whom 47 had coagulase-positive staphylococcal bacteremia. A total of 30% of the 47 patients with coagulase-positive staphylococcal bacteremia had a TAA titer of 1:8 or more, and an additional 30% had a titer of 1:2 or 1:4. High TAA titers were most often connected with coagulase-positive staphylococcal endocarditis, osteomyelitis, and deep wound infections. None of the six coagulase-negative patients with staphylococcal bacteremia nor any of the 92 controls had titers exceeding 1:1. A total of 10% of the other patients with bacteremia showed positive results on the TAA test at low titer levels. Compared to the antistaphylolysin value, the TAA test was about equally specific but more sensitive.

  5. Mechanisms of bacterial pathogenicity

    PubMed Central

    Wilson, J; Schurr, M; LeBlanc, C; Ramamurthy, R; Buchanan, K; Nickerson, C

    2002-01-01

    Pathogenic bacteria utilise a number of mechanisms to cause disease in human hosts. Bacterial pathogens express a wide range of molecules that bind host cell targets to facilitate a variety of different host responses. The molecular strategies used by bacteria to interact with the host can be unique to specific pathogens or conserved across several different species. A key to fighting bacterial disease is the identification and characterisation of all these different strategies. The availability of complete genome sequences for several bacterial pathogens coupled with bioinformatics will lead to significant advances toward this goal. PMID:11930024

  6. Unusual staphylococcal toxic shock syndrome presenting as a scarlet-like fever.

    PubMed

    Andrey, D O; Ferry, T; Siegenthaler, N; Fletcher, C; Calmy, A; Lina, G; Emonet, S

    2015-11-01

    Diagnosis of nonmenstrual staphylococcal toxic shock syndrome (TSS) is often challenging. A female medical colleague had a rare entity, a staphylococcal pharyngitis complicated by TSS. The diagnosis was confirmed by isolation of tst-positive Staphylococcus aureus in throat culture and by identification of a specific Vβ2 expansion pattern of her T lymphocytes. Recent improvements in microbiology can be of great help for the diagnosis of nonmenstrual TSS.

  7. Unusual staphylococcal toxic shock syndrome presenting as a scarlet-like fever

    PubMed Central

    Andrey, D.O.; Ferry, T.; Siegenthaler, N.; Fletcher, C.; Calmy, A.; Lina, G.; Emonet, S.

    2015-01-01

    Diagnosis of nonmenstrual staphylococcal toxic shock syndrome (TSS) is often challenging. A female medical colleague had a rare entity, a staphylococcal pharyngitis complicated by TSS. The diagnosis was confirmed by isolation of tst-positive Staphylococcus aureus in throat culture and by identification of a specific Vβ2 expansion pattern of her T lymphocytes. Recent improvements in microbiology can be of great help for the diagnosis of nonmenstrual TSS. PMID:26543563

  8. Unusual staphylococcal toxic shock syndrome presenting as a scarlet-like fever.

    PubMed

    Andrey, D O; Ferry, T; Siegenthaler, N; Fletcher, C; Calmy, A; Lina, G; Emonet, S

    2015-11-01

    Diagnosis of nonmenstrual staphylococcal toxic shock syndrome (TSS) is often challenging. A female medical colleague had a rare entity, a staphylococcal pharyngitis complicated by TSS. The diagnosis was confirmed by isolation of tst-positive Staphylococcus aureus in throat culture and by identification of a specific Vβ2 expansion pattern of her T lymphocytes. Recent improvements in microbiology can be of great help for the diagnosis of nonmenstrual TSS. PMID:26543563

  9. Prevalence and Genotype Allocation of Pathogenic Leptospira Species in Small Mammals from Various Habitat Types in Germany.

    PubMed

    Obiegala, Anna; Woll, Dietlinde; Karnath, Carolin; Silaghi, Cornelia; Schex, Susanne; Eßbauer, Sandra; Pfeffer, Martin

    2016-03-01

    Small mammals serve as most important reservoirs for Leptospira spp., the causative agents of Leptospirosis, which is one of the most neglected and widespread zoonotic diseases worldwide. The knowledge about Leptospira spp. occurring in small mammals from Germany is scarce. Thus, this study's objectives were to investigate the occurrence of Leptospira spp. and the inherent sequence types in small mammals from three different study sites: a forest in southern Germany (site B1); a National Park in south-eastern Germany (site B2) and a renaturalised area, in eastern Germany (site S) where small mammals were captured. DNA was extracted from kidneys of small mammals and tested for Leptospira spp. by real-time PCR. Positive samples were further analysed by duplex and conventional PCRs. For 14 positive samples, multi locus sequence typing (MLST) was performed. Altogether, 1213 small mammals were captured: 216 at site B1, 456 at site B2 and 541 at site S belonging to following species: Sorex (S.) araneus, S. coronatus, Apodemus (A.) flavicollis, Myodes glareolus, Microtus (Mi.) arvalis, Crocidura russula, Arvicola terrestris, A. agrarius, Mustela nivalis, Talpa europaea, and Mi. agrestis. DNA of Leptospira spp. was detected in 6% of all small mammals. At site B1, 25 small mammals (11.6%), at site B2, 15 small mammals (3.3%) and at site S, 33 small mammals (6.1%) were positive for Leptospira spp. Overall, 54 of the positive samples were further determined as L. kirschneri, nine as L. interrogans and four as L. borgpetersenii while five real-time PCR-positive samples could not be further determined by conventional PCR. MLST results revealed focal occurrence of L. interrogans and L. kirschneri sequence type (ST) 117 while L. kirschneri ST 110 was present in small mammals at all three sites. Further, this study provides evidence for a particular host association of L. borgpetersenii to mice of the genus Apodemus. PMID:27015596

  10. Biodegradation of Selected Nigerian Fruit Peels by the use of a Non-pathogenic Rhizobium species CWP G34B.

    PubMed

    Esther Boboye, Bolatito; Ajayi, George Olarewaju

    2012-01-01

    This study was carried out to determine the ability of Rhizobium species CWP G34B to degrade the peels of selected Nigerian fruits. The potential of the bacterium to digest some carbon sources (lactose, maltose, sucrose and mannitol) and peels of some Nigerian fruits (pineapple, orange, plantain, banana, pawpaw and mango fruits) was investigated by growing the organism on the substances separately after which DNSA reagent method was used to quantify glucose released into the medium. The results showed that the bacterium was able to degrade all the carbohydrates with the highest and the lowest glucose concentrations of 5.52 mg/ml for lactose and 0.50 mg/ml for mannitol. The carbohydrate-catabolic-enzyme (CCE) activity ranged from 0.169 mg/ml to 1.346 mg/ml glucose per mg/ml protein. Mannitol exhibited the highest CCE activity while the lowest activity was observed in the presence of sucrose. The amount of extracellular protein synthesized was highest (9.803 mg/ml) in the presence of maltose and lowest (0.925 mg/ml) in mannitol. The mean polygalacturonase activity was 0.54 unit/ml when the bacterium was grown in pectin in contrast to 0.28 unit/ml when it was grown in mannitol. The bacterium showed ability to breakdown the peels of the Nigerian fruits with the highest capability in banana and pineapple (0.42 and 0.41 mg/ml glucose per mg/ml protein respectively). The fruit-peel-degrading enzyme activity was lowest in orange peel (0.75 unit/ml). PMID:23166567

  11. Prevalence and Genotype Allocation of Pathogenic Leptospira Species in Small Mammals from Various Habitat Types in Germany

    PubMed Central

    Karnath, Carolin; Silaghi, Cornelia; Schex, Susanne; Eßbauer, Sandra; Pfeffer, Martin

    2016-01-01

    Small mammals serve as most important reservoirs for Leptospira spp., the causative agents of Leptospirosis, which is one of the most neglected and widespread zoonotic diseases worldwide. The knowledge about Leptospira spp. occurring in small mammals from Germany is scarce. Thus, this study’s objectives were to investigate the occurrence of Leptospira spp. and the inherent sequence types in small mammals from three different study sites: a forest in southern Germany (site B1); a National Park in south-eastern Germany (site B2) and a renaturalised area, in eastern Germany (site S) where small mammals were captured. DNA was extracted from kidneys of small mammals and tested for Leptospira spp. by real-time PCR. Positive samples were further analysed by duplex and conventional PCRs. For 14 positive samples, multi locus sequence typing (MLST) was performed. Altogether, 1213 small mammals were captured: 216 at site B1, 456 at site B2 and 541 at site S belonging to following species: Sorex (S.) araneus, S. coronatus, Apodemus (A.) flavicollis, Myodes glareolus, Microtus (Mi.) arvalis, Crocidura russula, Arvicola terrestris, A. agrarius, Mustela nivalis, Talpa europaea, and Mi. agrestis. DNA of Leptospira spp. was detected in 6% of all small mammals. At site B1, 25 small mammals (11.6%), at site B2, 15 small mammals (3.3%) and at site S, 33 small mammals (6.1%) were positive for Leptospira spp. Overall, 54 of the positive samples were further determined as L. kirschneri, nine as L. interrogans and four as L. borgpetersenii while five real-time PCR-positive samples could not be further determined by conventional PCR. MLST results revealed focal occurrence of L. interrogans and L. kirschneri sequence type (ST) 117 while L. kirschneri ST 110 was present in small mammals at all three sites. Further, this study provides evidence for a particular host association of L. borgpetersenii to mice of the genus Apodemus. PMID:27015596

  12. Prevalence and Genotype Allocation of Pathogenic Leptospira Species in Small Mammals from Various Habitat Types in Germany.

    PubMed

    Obiegala, Anna; Woll, Dietlinde; Karnath, Carolin; Silaghi, Cornelia; Schex, Susanne; Eßbauer, Sandra; Pfeffer, Martin

    2016-03-01

    Small mammals serve as most important reservoirs for Leptospira spp., the causative agents of Leptospirosis, which is one of the most neglected and widespread zoonotic diseases worldwide. The knowledge about Leptospira spp. occurring in small mammals from Germany is scarce. Thus, this study's objectives were to investigate the occurrence of Leptospira spp. and the inherent sequence types in small mammals from three different study sites: a forest in southern Germany (site B1); a National Park in south-eastern Germany (site B2) and a renaturalised area, in eastern Germany (site S) where small mammals were captured. DNA was extracted from kidneys of small mammals and tested for Leptospira spp. by real-time PCR. Positive samples were further analysed by duplex and conventional PCRs. For 14 positive samples, multi locus sequence typing (MLST) was performed. Altogether, 1213 small mammals were captured: 216 at site B1, 456 at site B2 and 541 at site S belonging to following species: Sorex (S.) araneus, S. coronatus, Apodemus (A.) flavicollis, Myodes glareolus, Microtus (Mi.) arvalis, Crocidura russula, Arvicola terrestris, A. agrarius, Mustela nivalis, Talpa europaea, and Mi. agrestis. DNA of Leptospira spp. was detected in 6% of all small mammals. At site B1, 25 small mammals (11.6%), at site B2, 15 small mammals (3.3%) and at site S, 33 small mammals (6.1%) were positive for Leptospira spp. Overall, 54 of the positive samples were further determined as L. kirschneri, nine as L. interrogans and four as L. borgpetersenii while five real-time PCR-positive samples could not be further determined by conventional PCR. MLST results revealed focal occurrence of L. interrogans and L. kirschneri sequence type (ST) 117 while L. kirschneri ST 110 was present in small mammals at all three sites. Further, this study provides evidence for a particular host association of L. borgpetersenii to mice of the genus Apodemus.

  13. Biodegradation of Selected Nigerian Fruit Peels by the use of a Non-pathogenic Rhizobium species CWP G34B

    PubMed Central

    Esther Boboye, Bolatito; Ajayi, George Olarewaju

    2012-01-01

    This study was carried out to determine the ability of Rhizobium species CWP G34B to degrade the peels of selected Nigerian fruits. The potential of the bacterium to digest some carbon sources (lactose, maltose, sucrose and mannitol) and peels of some Nigerian fruits (pineapple, orange, plantain, banana, pawpaw and mango fruits) was investigated by growing the organism on the substances separately after which DNSA reagent method was used to quantify glucose released into the medium. The results showed that the bacterium was able to degrade all the carbohydrates with the highest and the lowest glucose concentrations of 5.52 mg/ml for lactose and 0.50 mg/ml for mannitol. The carbohydrate-catabolic-enzyme (CCE) activity ranged from 0.169 mg/ml to 1.346 mg/ml glucose per mg/ml protein. Mannitol exhibited the highest CCE activity while the lowest activity was observed in the presence of sucrose. The amount of extracellular protein synthesized was highest (9.803 mg/ml) in the presence of maltose and lowest (0.925 mg/ml) in mannitol. The mean polygalacturonase activity was 0.54 unit/ml when the bacterium was grown in pectin in contrast to 0.28 unit/ml when it was grown in mannitol. The bacterium showed ability to breakdown the peels of the Nigerian fruits with the highest capability in banana and pineapple (0.42 and 0.41 mg/ml glucose per mg/ml protein respectively). The fruit-peel-degrading enzyme activity was lowest in orange peel (0.75 unit/ml). PMID:23166567

  14. The Production of Reactive Oxygen Species Is a Universal Action Mechanism of Amphotericin B against Pathogenic Yeasts and Contributes to the Fungicidal Effect of This Drug

    PubMed Central

    Mesa-Arango, Ana Cecilia; Trevijano-Contador, Nuria; Román, Elvira; Sánchez-Fresneda, Ruth; Casas, Celia; Herrero, Enrique; Argüelles, Juan Carlos; Pla, Jesús; Cuenca-Estrella, Manuel

    2014-01-01

    Amphotericin B (AMB) is an antifungal drug that binds to ergosterol and forms pores at the cell membrane, causing the loss of ions. In addition, AMB induces the accumulation of reactive oxygen species (ROS), and although these molecules have multiple deleterious effects on fungal cells, their specific role in the action mechanism of AMB remains unknown. In this work, we studied the role of ROS in the action mechanism of AMB. We determined the intracellular induction of ROS in 44 isolates of different pathogenic yeast species (Candida albicans, Candida parapsilosis, Candida glabrata, Candida tropicalis, Candida krusei, Cryptococcus neoformans, and Cryptococcus gattii). We also characterized the production of ROS in AMB-resistant isolates. We found that AMB induces the formation of ROS in all the species tested. The inhibition of the mitochondrial respiratory chain by rotenone blocked the induction of ROS by AMB and provided protection from the killing action of the antifungal. Moreover, this phenomenon was absent in strains that displayed resistance to AMB. These strains showed an alteration in the respiration rate and mitochondrial membrane potential and also had higher catalase activity than that of the AMB-susceptible strains. Consistently, AMB failed to induce protein carbonylation in the resistant strains. Our data demonstrate that the production of ROS by AMB is a universal and important action mechanism that is correlated with the fungicidal effect and might explain the low rate of resistance to the molecule. Finally, these data provide an opportunity to design new strategies to improve the efficacy of this antifungal. PMID:25155595

  15. The production of reactive oxygen species is a universal action mechanism of Amphotericin B against pathogenic yeasts and contributes to the fungicidal effect of this drug.

    PubMed

    Mesa-Arango, Ana Cecilia; Trevijano-Contador, Nuria; Román, Elvira; Sánchez-Fresneda, Ruth; Casas, Celia; Herrero, Enrique; Argüelles, Juan Carlos; Pla, Jesús; Cuenca-Estrella, Manuel; Zaragoza, Oscar

    2014-11-01

    Amphotericin B (AMB) is an antifungal drug that binds to ergosterol and forms pores at the cell membrane, causing the loss of ions. In addition, AMB induces the accumulation of reactive oxygen species (ROS), and although these molecules have multiple deleterious effects on fungal cells, their specific role in the action mechanism of AMB remains unknown. In this work, we studied the role of ROS in the action mechanism of AMB. We determined the intracellular induction of ROS in 44 isolates of different pathogenic yeast species (Candida albicans, Candida parapsilosis, Candida glabrata, Candida tropicalis, Candida krusei, Cryptococcus neoformans, and Cryptococcus gattii). We also characterized the production of ROS in AMB-resistant isolates. We found that AMB induces the formation of ROS in all the species tested. The inhibition of the mitochondrial respiratory chain by rotenone blocked the induction of ROS by AMB and provided protection from the killing action of the antifungal. Moreover, this phenomenon was absent in strains that displayed resistance to AMB. These strains showed an alteration in the respiration rate and mitochondrial membrane potential and also had higher catalase activity than that of the AMB-susceptible strains. Consistently, AMB failed to induce protein carbonylation in the resistant strains. Our data demonstrate that the production of ROS by AMB is a universal and important action mechanism that is correlated with the fungicidal effect and might explain the low rate of resistance to the molecule. Finally, these data provide an opportunity to design new strategies to improve the efficacy of this antifungal. PMID:25155595

  16. Sequence determination of rRNA genes of pathogenic Vibrio species and whole-cell identification of Vibrio vulnificus with rRNA-targeted oligonucleotide probes.

    PubMed

    Aznar, R; Ludwig, W; Amann, R I; Schleifer, K H

    1994-04-01

    A comparative analysis of seven new 16S rRNA gene sequences of pathogenic Vibrio species with previously published vibrio sequences confirmed that Vibrio vulnificus represents a group that is not closely related to the core organisms of the genus Vibrio. In addition, we found that V. vulnificus, Listonella (Vibrio) anguillarum and Vibrio diazotrophicus branch off separately from the core group. A comparison of the 16S rRNA gene sequences of V. vulnificus strains belonging to biotypes 1 and 2 revealed that the sequences of all but four biotype 1 strains were identical to each other but slightly different (17 bases) from the sequences of the rest of the V. vulnificus strains investigated. In addition, the sequences of variable regions of the 23S rRNA genes of Vibrio fluvialis, Vibrio furnissii, Vibrio harveyi, Vibrio cholerae, and V. vulnificus C7184 and TW1 were determined, aligned, and compared with all available bacterial 23S rRNA sequences in order to search for specific target sites. As a result, four oligonucleotide probes specific for V. vulnificus were synthesized, and the specificities of these probes were evaluated by dot blot hybridization to membrane-bound RNAs from 21 V. vulnificus strains, 13 strains belonging to other Vibrio species, 61 strains belonging to species that are members of the alpha, beta, and gamma subclasses of the Proteobacteria, and 3 eucaryotic microorganisms. Two probes hybridized with all of the V. vulnificus strains tested, and the other two probes distinguished V. vulnificus biotype 1 strains from all other organisms. In situ identification of V. vulnificus by using tetramethylrhodamine- or fluorescein-labelled oligonucleotides is now possible.

  17. Detection and identification of pathogenic trypanosome species in tsetse flies along the Comoé River in Côte d’Ivoire

    PubMed Central

    Djohan, Vincent; Kaba, Dramane; Rayaissé, Jean-Baptiste; Dayo, Guiguigbaza-Kossigan; Coulibaly, Bamoro; Salou, Ernest; Dofini, Fabien; Kouadio, Alain De Marie Koffi; Menan, Hervé; Solano, Philippe

    2015-01-01

    In order to identify pathogenic trypanosomes responsible for African trypanosomiasis, and to better understand tsetse-trypanosome relationships, surveys were undertaken in three sites located in different eco-climatic areas in Côte d’Ivoire during the dry and rainy seasons. Tsetse flies were caught during five consecutive days using biconical traps, dissected and microscopically examined looking for trypanosome infection. Samples from infected flies were tested by PCR using specific primers for Trypanosoma brucei s.l., T. congolense savannah type, T. congolense forest type and T. vivax. Of 1941 tsetse flies caught including four species, i.e. Glossina palpalis palpalis, G. p. gambiensis, G. tachinoides and G. medicorum, 513 (26%) were dissected and 60 (12%) were found positive by microscopy. Up to 41% of the infections were due to T. congolense savannah type, 30% to T. vivax, 20% to T. congolense forest type and 9% due to T. brucei s.l. All four trypanosome species and subgroups were identified from G. tachinoides and G. p. palpalis, while only two were isolated from G. p. gambiensis (T. brucei s.l., T. congolense savannah type) and G. medicorum (T. congolense forest, savannah types). Mixed infections were found in 25% of cases and all involved T. congolense savannah type with another trypanosome species. The simultaneous occurrence of T. brucei s.l., and tsetse from the palpalis group may suggest that human trypanosomiasis can still be a constraint in these localities, while high rates of T. congolense and T. vivax in the area suggest a potential risk of animal trypanosomiasis in livestock along the Comoé River. PMID:26035296

  18. Detection and identification of pathogenic trypanosome species in tsetse flies along the Comoé River in Côte d'Ivoire.

    PubMed

    Djohan, Vincent; Kaba, Dramane; Rayaissé, Jean-Baptiste; Dayo, Guiguigbaza-Kossigan; Coulibaly, Bamoro; Salou, Ernest; Dofini, Fabien; Kouadio, Alain De Marie Koffi; Menan, Hervé; Solano, Philippe

    2015-01-01

    In order to identify pathogenic trypanosomes responsible for African trypanosomiasis, and to better understand tsetse-trypanosome relationships, surveys were undertaken in three sites located in different eco-climatic areas in Côte d'Ivoire during the dry and rainy seasons. Tsetse flies were caught during five consecutive days using biconical traps, dissected and microscopically examined looking for trypanosome infection. Samples from infected flies were tested by PCR using specific primers for Trypanosoma brucei s.l., T. congolense savannah type, T. congolense forest type and T. vivax. Of 1941 tsetse flies caught including four species, i.e. Glossina palpalis palpalis, G. p. gambiensis, G. tachinoides and G. medicorum, 513 (26%) were dissected and 60 (12%) were found positive by microscopy. Up to 41% of the infections were due to T. congolense savannah type, 30% to T. vivax, 20% to T. congolense forest type and 9% due to T. brucei s.l. All four trypanosome species and subgroups were identified from G. tachinoides and G. p. palpalis, while only two were isolated from G. p. gambiensis (T. brucei s.l., T. congolense savannah type) and G. medicorum (T. congolense forest, savannah types). Mixed infections were found in 25% of cases and all involved T. congolense savannah type with another trypanosome species. The simultaneous occurrence of T. brucei s.l., and tsetse from the palpalis group may suggest that human trypanosomiasis can still be a constraint in these localities, while high rates of T. congolense and T. vivax in the area suggest a potential risk of animal trypanosomiasis in livestock along the Comoé River.

  19. Prevalence and Antibiotic Resistance of Gram-Negative Pathogenic Bacteria Species Isolated from Periplaneta americana and Blattella germanica in Varanasi, India

    PubMed Central

    Wannigama, D Leshan; Dwivedi, Rishabh; Zahraei-Ramazani, Alireza

    2014-01-01

    Background Cockroaches are among the medically important pests found within the human habitations that cause serious public health problems. They may harbor a number of pathogenic bacteria on the external surface with antibiotic resistance. Hence, they are regarded as major microbial vectors. This study investigates the prevalence and antibiotic resistance of Gram-negative pathogenic bacteria species isolated from Periplaneta americana and Blattella germanica in Varanasi, India. Methods: Totally, 203 adult cockroaches were collected form 44 households and 52 food-handling establishments by trapping. Bacteriological examination of external surfaces of Pe. americana and Bl. germanica were carried out using standard method and antibiotics susceptibility profiles of the isolates were determined using Kirby-Bauer disc diffusion methods. Results: Among the places, we found that 54% had cockroache infestation in households and 77% in food- handling establishments. There was no significant different between the overall bacteria load of the external surface in Pe. americana (64.04%) and Bl. germanica (35.96%). However the predominant bacteria on cockroaches were Klebsiella pneumonia, Escherichia coli, Enterobacter aerogenes, and Pseudomonas aeruginosa. However, Kl. pneumoniae and Ps. aeruginosa were the most prevalent, drug-resistant strains were isolated from the cockroaches with 100% resistance to sulfamethoxazole/trimethoprim and ampicillin. For individual strains of bacteria, Escherichia coli was found to have multi-resistance to four antibiotic tested, Citrobacter freundii four, Enterobacter aerogenes and Proteus mirabilis to three. Conclusion: Cockroaches are uniformly distributed in domestic environment, which can be a possible vector for transmission of drug-resistant bacteria and food-borne diseases. PMID:25629061

  20. Multiple-Strain Approach and Probabilistic Modeling of Consumer Habits in Quantitative Microbial Risk Assessment: A Quantitative Assessment of Exposure to Staphylococcal Enterotoxin A in Raw Milk.

    PubMed

    Crotta, Matteo; Rizzi, Rita; Varisco, Giorgio; Daminelli, Paolo; Cunico, Elena Cosciani; Luini, Mario; Graber, Hans Ulrich; Paterlini, Franco; Guitian, Javier

    2016-03-01

    Quantitative microbial risk assessment (QMRA) models are extensively applied to inform management of a broad range of food safety risks. Inevitably, QMRA modeling involves an element of simplification of the biological process of interest. Two features that are frequently simplified or disregarded are the pathogenicity of multiple strains of a single pathogen and consumer behavior at the household level. In this study, we developed a QMRA model with a multiple-strain approach and a consumer phase module (CPM) based on uncertainty distributions fitted from field data. We modeled exposure to staphylococcal enterotoxin A in raw milk in Lombardy; a specific enterotoxin production module was thus included. The model is adaptable and could be used to assess the risk related to other pathogens in raw milk as well as other staphylococcal enterotoxins. The multiplestrain approach, implemented as a multinomial process, allowed the inclusion of variability and uncertainty with regard to pathogenicity at the bacterial level. Data from 301 questionnaires submitted to raw milk consumers were used to obtain uncertainty distributions for the CPM. The distributions were modeled to be easily updatable with further data or evidence. The sources of uncertainty due to the multiple-strain approach and the CPM were identified, and their impact on the output was assessed by comparing specific scenarios to the baseline. When the distributions reflecting the uncertainty in consumer behavior were fixed to the 95th percentile, the risk of exposure increased up to 160 times. This reflects the importance of taking into consideration the diversity of consumers' habits at the household level and the impact that the lack of knowledge about variables in the CPM can have on the final QMRA estimates. The multiple-strain approach lends itself to use in other food matrices besides raw milk and allows the model to better capture the complexity of the real world and to be capable of geographical

  1. Quorum sensing-mediated regulation of staphylococcal virulence and antibiotic resistance.

    PubMed

    Singh, Rachna; Ray, Pallab

    2014-01-01

    Accessory gene regulator (agr)-mediated quorum sensing plays a central role in staphylococcal pathogenesis. It primarily upregulates secreted virulence factors and downregulates cell surface proteins, thereby governing invasiveness of staphylococci and cell dispersal from biofilms. Except for α- and β-PSMs, which are directly controlled by AgrA, the effector functions of agr are primarily mediated by RNAIII, a regulatory RNA encoded by this operon. agr phenotype and expression considerably influence the chronicity of an infection. It has also been linked with altered susceptibility of Staphylococcus aureus against antibiotics. Four classes of S. aureus and Staphylococcus epidermidis AIPs exist based on sequence variation, and lead to inter-strain and species cross-inhibition. Certain agr classes have been associated with specific clonal complexes, disease syndromes and intermediate-susceptibility to glycopeptides. It is also being investigated as a prophylactic and therapeutic target. This article describes the presently available literature regarding the role of agr in S. aureus and S. epidermidis infections.

  2. Characterization of the stable, acid-induced, molten globule-like state of staphylococcal nuclease.

    PubMed Central

    Fink, A. L.; Calciano, L. J.; Goto, Y.; Nishimura, M.; Swedberg, S. A.

    1993-01-01

    Titration of a salt-free solution of native staphylococcal nuclease by HCl leads to an unfolding transition in the vicinity of pH 4, as determined by near- and far-UV circular dichroism. At pH 2-3, the protein is substantially unfolded. The addition of further HCl results in a second transition, this one to a more structured species (the A state) with the properties of an expanded molten globule, namely substantial secondary structure, little or no tertiary structure, relatively compact size as determined by hydrodynamic radius, and the ability to bind the hydrophobic dye 1-anilino-8-naphthalene sulfonic acid. The addition of anions, in the form of neutral salts, to the acid-unfolded state at pH 2 also causes a transition leading to the A state. Fourier transform infrared analysis of the amide I band was used to compare the amount and type of secondary structure in the native and A states. A significant decrease in alpha-helix structure, with a corresponding increase in beta or extended structure, was observed in the A state, compared to the native state. A model to account for such compact denatured states is proposed. PMID:8358298

  3. Binding and activation of major histocompatibility complex class II-deficient macrophages by staphylococcal exotoxins

    NASA Technical Reports Server (NTRS)

    Beharka, A. A.; Armstrong, J. W.; Iandolo, J. J.; Chapes, S. K.; Spooner, B. S. (Principal Investigator)

    1994-01-01

    Macrophages from C2D transgenic mice deficient in the expression of major histocompatibility complex (MHC) class II proteins were used to identify binding sites for superantigens distinct from the MHC class II molecule. Iodinated staphylococcal enterotoxins A and B (SEA and SEB) and exfoliative toxins A and B (ETA and ETB) bound to C2D macrophages in a concentration-dependent and competitive manner. All four toxins increased F-actin concentration within 30 s of their addition to C2D macrophages, indicating that signal transduction occurred in response to toxin in the absence of class II MHC. Furthermore, ETA, ETB, SEA, and, to a lesser extent, SEB induced C2D macrophages to produce interleukin 6. Several molecular species on C2D macrophages with molecular masses of 140, 97, 61, 52, 43, and 37 kDa bound SEA in immunoprecipitation experiments. These data indicate the presence of novel, functionally active toxin binding sites on murine macrophages distinct from MHC class II molecules.

  4. A bone sialoprotein-binding protein from Staphylococcus aureus: a member of the staphylococcal Sdr family.

    PubMed Central

    Tung, H s; Guss, B; Hellman, U; Persson, L; Rubin, K; Rydén, C

    2000-01-01

    Staphylococcus aureus bacteria, isolated from bone and joint infections, specifically interact with bone sialoprotein (BSP), a glycoprotein of bone and dentine extracellular matrix, via a cell-surface protein of M(r) 97000 [Yacoub, Lindahl, Rubin, Wendel, Heinegârd and Rydén, (1994) Eur. J. Biochem. 222, 919-925]. Amino acid sequences of seven trypsin fragments from the 97000-M(r) BSP-binding protein were determined. A gene encoding a protein encompassing all seven peptide sequences was identified from chromosomal DNA isolated from S. aureus strain O24. This gene encodes a protein with 1171 amino acids, called BSP-binding protein (Bbp), which displays similarity to recently described proteins of the Sdr family from S. aureus. SdrC, SdrD and SdrE encode putative cell-surface proteins with no described ligand specificity. Bbp also shows similarity to a fibrinogen-binding protein from S. epidermidis called Fbe. A serine-aspartic acid repeat sequence was found close to the cell-wall-anchoring Leu-Pro-Xaa-Thr-Gly sequence in the C-terminal end of the protein. Escherichia coli cells were transformed with an expression vector containing a major part of the bbp gene fused to the gene for glutathione S-transferase. The affinity-purified fusion protein bound radiolabelled native BSP, and inhibited the binding of radiolabelled BSP to staphylococcal cells. Serum from patients suffering from bone and joint infection contained antibodies that reacted with the fusion protein of the BSP-binding protein, indicating that the protein is expressed during an infection and is immunogenic. The S. aureus Bbp protein may be important in the localization of bacteria to bone tissue, and thus might be of relevance in the pathogenicity of osteomyelitis. PMID:10642520

  5. In vivo efficacy of anuran trypsin inhibitory peptides against staphylococcal skin infection and the impact of peptide cyclization.

    PubMed

    Malik, U; Silva, O N; Fensterseifer, I C M; Chan, L Y; Clark, R J; Franco, O L; Daly, N L; Craik, D J

    2015-04-01

    Staphylococcus aureus is a virulent pathogen that is responsible for a wide range of superficial and invasive infections. Its resistance to existing antimicrobial drugs is a global problem, and the development of novel antimicrobial agents is crucial. Antimicrobial peptides from natural resources offer potential as new treatments against staphylococcal infections. In the current study, we have examined the antimicrobial properties of peptides isolated from anuran skin secretions and cyclized synthetic analogues of these peptides. The structures of the peptides were elucidated by nuclear magnetic resonance (NMR) spectroscopy, revealing high structural and sequence similarity with each other and with sunflower trypsin inhibitor 1 (SFTI-1). SFTI-1 is an ultrastable cyclic peptide isolated from sunflower seeds that has subnanomolar trypsin inhibitory activity, and this scaffold offers pharmaceutically relevant characteristics. The five anuran peptides were nonhemolytic and noncytotoxic and had trypsin inhibitory activities similar to that of SFTI-1. They demonstrated weak in vitro inhibitory activities against S. aureus, but several had strong antibacterial activities against S. aureus in an in vivo murine wound infection model. pYR, an immunomodulatory peptide from Rana sevosa, was the most potent, with complete bacterial clearance at 3 mg · kg(-1). Cyclization of the peptides improved their stability but was associated with a concomitant decrease in antimicrobial activity. In summary, these anuran peptides are promising as novel therapeutic agents for treating infections from a clinically resistant pathogen. PMID:25624332

  6. In vivo efficacy of anuran trypsin inhibitory peptides against staphylococcal skin infection and the impact of peptide cyclization.

    PubMed

    Malik, U; Silva, O N; Fensterseifer, I C M; Chan, L Y; Clark, R J; Franco, O L; Daly, N L; Craik, D J

    2015-04-01

    Staphylococcus aureus is a virulent pathogen that is responsible for a wide range of superficial and invasive infections. Its resistance to existing antimicrobial drugs is a global problem, and the development of novel antimicrobial agents is crucial. Antimicrobial peptides from natural resources offer potential as new treatments against staphylococcal infections. In the current study, we have examined the antimicrobial properties of peptides isolated from anuran skin secretions and cyclized synthetic analogues of these peptides. The structures of the peptides were elucidated by nuclear magnetic resonance (NMR) spectroscopy, revealing high structural and sequence similarity with each other and with sunflower trypsin inhibitor 1 (SFTI-1). SFTI-1 is an ultrastable cyclic peptide isolated from sunflower seeds that has subnanomolar trypsin inhibitory activity, and this scaffold offers pharmaceutically relevant characteristics. The five anuran peptides were nonhemolytic and noncytotoxic and had trypsin inhibitory activities similar to that of SFTI-1. They demonstrated weak in vitro inhibitory activities against S. aureus, but several had strong antibacterial activities against S. aureus in an in vivo murine wound infection model. pYR, an immunomodulatory peptide from Rana sevosa, was the most potent, with complete bacterial clearance at 3 mg · kg(-1). Cyclization of the peptides improved their stability but was associated with a concomitant decrease in antimicrobial activity. In summary, these anuran peptides are promising as novel therapeutic agents for treating infections from a clinically resistant pathogen.

  7. In Vivo Efficacy of Anuran Trypsin Inhibitory Peptides against Staphylococcal Skin Infection and the Impact of Peptide Cyclization

    PubMed Central

    Malik, U.; Silva, O. N.; Fensterseifer, I. C. M.; Chan, L. Y.; Clark, R. J.; Franco, O. L.; Daly, N. L.

    2015-01-01

    Staphylococcus aureus is a virulent pathogen that is responsible for a wide range of superficial and invasive infections. Its resistance to existing antimicrobial drugs is a global problem, and the development of novel antimicrobial agents is crucial. Antimicrobial peptides from natural resources offer potential as new treatments against staphylococcal infections. In the current study, we have examined the antimicrobial properties of peptides isolated from anuran skin secretions and cyclized synthetic analogues of these peptides. The structures of the peptides were elucidated by nuclear magnetic resonance (NMR) spectroscopy, revealing high structural and sequence similarity with each other and with sunflower trypsin inhibitor 1 (SFTI-1). SFTI-1 is an ultrastable cyclic peptide isolated from sunflower seeds that has subnanomolar trypsin inhibitory activity, and this scaffold offers pharmaceutically relevant characteristics. The five anuran peptides were nonhemolytic and noncytotoxic and had trypsin inhibitory activities similar to that of SFTI-1. They demonstrated weak in vitro inhibitory activities against S. aureus, but several had strong antibacterial activities against S. aureus in an in vivo murine wound infection model. pYR, an immunomodulatory peptide from Rana sevosa, was the most potent, with complete bacterial clearance at 3 mg · kg−1. Cyclization of the peptides improved their stability but was associated with a concomitant decrease in antimicrobial activity. In summary, these anuran peptides are promising as novel therapeutic agents for treating infections from a clinically resistant pathogen. PMID:25624332

  8. In vitro synergistic effect of the CM11 antimicrobial peptide in combination with common antibiotics against clinical isolates of six species of multidrug-resistant pathogenic bacteria.

    PubMed

    Amani, Jafar; Barjini, Kamal A; Moghaddam, Mehrdad M; Asadi, Asadollah

    2015-01-01

    During the last decades, increase of antibiotic resistance among pathogenic bacteria has been considered as a global concern. Therefore, it is important to find new antimicrobial agents and/or therapeutic strategies. In previous studies we investigated antibacterial activity of the CM11 peptide against multiple drug resistant clinical isolates of six bacteria species including Pseudomonas aeruginosa, Staphylococcus aureus, Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae and Salmonella typhimurium. In this study, in order to reduce treatment costs and the cytotoxic effect of CM11 peptide, was analyzed its synergic interaction with selected antibiotics. In this reason, specific antibiotics for each bacterium were selected considering the guidelines of the "Clinical and Laboratory Standards Institute". Based on the results , using a checkerboard procedure through the broth microdilution method, MICs of antibiotic agents alone and in combination with the peptide were determined. In most cases, synergistic effects between CM11 peptide and selected antibiotics against six bacteria species were observed as partial synergy. However, for S. aureus and P. aeruginosaa synergic interaction between peptide and selective antibiotics was observed with penicillin and ceftazidime, respectively. For K. pneumoniae, synergic effect was observed when CM11 peptide was used in combination with norfloxacin and also the combination of peptide with norfloxacin showed synergic effect against A. baumannii. Combination between the CM11 peptide and ciprofloxacin showed synergic effect on E. coli while only partial synergy was observed for S. typhimurium in combination with cefotaxime and ceftazidime. These results suggest that when selected antibiotic used in combination with the CM11 peptide, the dose of some antibiotics, especially the dose independent antibiotics, may be reduced for eliminating drug resistant bacteria.

  9. A proteomic characterization of water buffalo milk fractions describing PTM of major species and the identification of minor components involved in nutrient delivery and defense against pathogens.

    PubMed

    D'Ambrosio, Chiara; Arena, Simona; Salzano, Anna Maria; Renzone, Giovanni; Ledda, Luigi; Scaloni, Andrea

    2008-09-01

    Water buffalo has been studied in relation to the exclusive use of its milk for the manufacture of high-quality dairy products. Buffalo milk presents physicochemical features different from that of other ruminant species, such as a higher content of fatty acids and proteins. We report here a detailed proteomic analysis of buffalo skim milk, whey and milk fat globule membrane fractions. Notwithstanding the poor information available on buffalo genome, identification of protein isoforms corresponding to 72 genes was achieved by a combined approach based on 2-DE/MALDI-TOF PMF and 1-DE/muLC-ESI-IT-MS-MS. Major protein components, i.e. alpha(Sl)-, alpha(S2)-, beta-, kappa-caseins, alpha-lactalbumin and beta-lactoglobulin, wer