Triple-acting antimicrobial treatment for drug-resistant and intracellular Staphylococcus aureus

USDA-ARS?s Scientific Manuscript database

Multi-drug resistant bacteria are a persistent problem in modern health care, food safety and animal health. There is a need for new antimicrobials to replace over-used conventional antibiotics. Staphylococcus aureus (S. aureus) is a notorious pathogen for both animal and human health with multi-d...

Triple-acting antimicrobial treatment for drug-resistant and intracellular Staphylococcus aureus.

USDA-ARS?s Scientific Manuscript database

Multi-drug resistant bacteria are a persistent problem in modern health care, food safety and animal health. There is a need for new antimicrobials to replace over-used conventional antibiotics. Staphylococcus aureus (S. aureus) is a notorious pathogen for both animal and human health with multi-d...

Triple-acting Peptidoglycan hydrolase treatment for drug-resistant and intracellular Staphylococcus aureus

USDA-ARS?s Scientific Manuscript database

Multi-drug resistant bacteria are a persistent problem in modern health care, food safety and animal health. There is a need for new antimicrobials to replace over-used conventional antibiotics. Staphylococcus aureus (S. aureus) is a notorious pathogen for both animal and human health with multi-d...

Whole-genome sequencing of staphylococcus haemolyticus uncovers the extreme plasticity of its genome and the evolution of human-colonizing staphylococcal species.

PubMed

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

2005-11-01

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.

Quantitative Proteomic Analyses of Staphylococcus aureus Treated with Punicalagin, a Natural Antibiotic from Pomegranate that Disrupts Iron Homeostasis and Induces SOS

USDA-ARS?s Scientific Manuscript database

Staphylococcus aureus, a bacterial, food-borne pathogen of humans, can contaminate raw fruits and vegetables. While physical and chemical methods are available to control S. aureus, scientists are searching for inhibitory phytochemicals from plants. One promising compound from pomegranate is punica...

Community-associated methicillin resistant Staphylococcus aureus in south Florida hospital and recreational environments

USDA-ARS?s Scientific Manuscript database

Strains of methicillin resistant Staphylococcus aureus (MRSA), a frequent human pathogen, may also be found in the flora of healthy persons and in the environments that they frequent. Strains of MRSA circulating in the community classified as USA 300 are now found not only in the community but also...

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

Antibacterial screening of traditional herbal plants and standard antibiotics against some human bacterial pathogens.

PubMed

Awan, Uzma Azeem; Andleeb, Saiqa; Kiyani, Ayesha; Zafar, Atiya; Shafique, Irsa; Riaz, Nazia; Azhar, Muhammad Tehseen; Uddin, Hafeez

2013-11-01

Chloroformic and isoamyl alcohol extracts of Cinnnamomum zylanicum, Cuminum cyminum, Curcuma long Linn, Trachyspermum ammi and selected standard antibiotics were investigated for their in vitro antibacterial activity against six human bacterial pathogens. The antibacterial activity was evaluated and based on the zone of inhibition using agar disc diffusion method. The tested bacterial strains were Streptococcus pyogenes, Staphylococcus epidermidis, Klebsiella pneumonia, Staphylococcus aurues, Serratia marcesnces, and Pseudomonas aeruginosa. Ciprofloxacin showed highly significant action against K. pneumonia and S. epidermidis while Ampicillin and Amoxicillin indicated lowest antibacterial activity against tested pathogens. Among the plants chloroform and isoamyl alcohol extracts of C. cyminum, S. aromaticum and C. long Linn had significant effect against P. aeruginosa, S. marcesnces and S. pyogenes. Comparison of antibacterial activity of medicinal herbs and standard antibiotics was also recorded via activity index. Used medicinal plants have various phytochemicals which reasonably justify their use as antibacterial agent.

Ultra-low power laser stimulation impairs the adhesion of Staphylococcus aureus to primary human cells, and interferes with the expression of staphylococcal pathogenic factors.

PubMed

Petruzzelli, Sabina; Congiu, Antonio; Gallamini, Michele; Pompei, Raffaello

2014-04-01

Lasers are commonly used in several fields of medicine as a complementary therapy for internal medicine, surgery and also diagnostics. The efficacy of ultra-low level laser therapy (ULLLT) at power levels around 0.15 mW/cm(2) has been demonstrated both in in vitro experiments and in the clinical environment. This work used an ULLLT laser source to analyze its efficacy on Staphylococcus aureus adhesion to cells and on its ability to produce pathogenic factors. Laser stimulation succeeded in impairing the binding of S. aureus to primary human cells in culture and in inhibiting the expression of coagulase, one of the main staphylococcal pathogenic factors. The importance of the extracellular matrix (ECM) and the modification of the ECM redox potential in these activities were also evidenced.

Growth and adherence of Staphylococcus aureus were enhanced through the PGE2 produced by the activated COX-2/PGE2 pathway of infected oral epithelial cells

PubMed Central

Wang, Yuxia; Ren, Biao; Zhou, Xuedong; Liu, Shiyu; Zhou, Yujie; Li, Bolei; Jiang, Yaling; Li, Mingyun; Feng, Mingye

2017-01-01

Staphylococcus aureus is a major pathogen of varieties of oral mucous infection. Prostaglandin E2 (PGE2) is a pro-inflammatory factor and Cyclooxygenase 2 (COX-2) is a critical enzyme of PGE2 biosynthesis. The purpose of this study is to investigate whether Staphylococcus aureus can increase PGE2 production of oral epithelial cells and how PGE2 functions in the growth and adherence of Staphylococcus aureus. mRNA levels of COX-2, fnbpA and fnbpB were estimated by quantitative PCR. PGE2 production was measured by Enzyme Linked Immunosorbent Assay (ELISA). The binding biomass of Staphylococcus aureus to human fibronectin was investigated by crystal violet staining and confocal laser scanning microscopy and the adherent force was measured by atomic force microscope (AFM). The COX-2 mRNA level and PGE2 production were increased by Staphylococcus aureus. PGE2 promoted the growth and biofilm formation of Staphylococcus aureus, enhanced the attachment of Staphylococcus aureus to the human fibronectin as well as to the HOK cells. The transcription of fnbpB was up-regulated by PGE2 in both early and middle exponential phase but not fnbpA. These results suggest that the activation of COX-2/PGE2 pathway in oral epithelial cell by Staphylococcus aureus can in turn facilitate the growth and the ability to adhere of the pathogen. These findings uncover a new function of PGE2 and may lead to the potential of COX-2/PGE2 targeting in the therapy of inflammation and cancer in both which the COX-2/PGE2 pathway were observed activated. PMID:28472126

Growth and adherence of Staphylococcus aureus were enhanced through the PGE2 produced by the activated COX-2/PGE2 pathway of infected oral epithelial cells.

PubMed

Wang, Yuxia; Ren, Biao; Zhou, Xuedong; Liu, Shiyu; Zhou, Yujie; Li, Bolei; Jiang, Yaling; Li, Mingyun; Feng, Mingye; Cheng, Lei

2017-01-01

Staphylococcus aureus is a major pathogen of varieties of oral mucous infection. Prostaglandin E2 (PGE2) is a pro-inflammatory factor and Cyclooxygenase 2 (COX-2) is a critical enzyme of PGE2 biosynthesis. The purpose of this study is to investigate whether Staphylococcus aureus can increase PGE2 production of oral epithelial cells and how PGE2 functions in the growth and adherence of Staphylococcus aureus. mRNA levels of COX-2, fnbpA and fnbpB were estimated by quantitative PCR. PGE2 production was measured by Enzyme Linked Immunosorbent Assay (ELISA). The binding biomass of Staphylococcus aureus to human fibronectin was investigated by crystal violet staining and confocal laser scanning microscopy and the adherent force was measured by atomic force microscope (AFM). The COX-2 mRNA level and PGE2 production were increased by Staphylococcus aureus. PGE2 promoted the growth and biofilm formation of Staphylococcus aureus, enhanced the attachment of Staphylococcus aureus to the human fibronectin as well as to the HOK cells. The transcription of fnbpB was up-regulated by PGE2 in both early and middle exponential phase but not fnbpA. These results suggest that the activation of COX-2/PGE2 pathway in oral epithelial cell by Staphylococcus aureus can in turn facilitate the growth and the ability to adhere of the pathogen. These findings uncover a new function of PGE2 and may lead to the potential of COX-2/PGE2 targeting in the therapy of inflammation and cancer in both which the COX-2/PGE2 pathway were observed activated.

Fermentation of Propionibacterium acnes, a Commensal Bacterium in the Human Skin Microbiome, as Skin Probiotics against Methicillin-Resistant Staphylococcus aureus

PubMed Central

Yu, Jinghua; Kuo, Sherwin; Coda, Alvin; Jiang, Yong; Gallo, Richard L.; Huang, Chun-Ming

2013-01-01

Bacterial interference creates an ecological competition between commensal and pathogenic bacteria. Through fermentation of milk with gut-friendly bacteria, yogurt is an excellent aid to balance the bacteriological ecosystem in the human intestine. Here, we demonstrate that fermentation of glycerol with Propionibacterium acnes (P. acnes), a skin commensal bacterium, can function as a skin probiotic for in vitro and in vivo growth suppression of USA300, the most prevalent community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA). We also promote the notion that inappropriate use of antibiotics may eliminate the skin commensals, making it more difficult to fight pathogen infection. This study warrants further investigation to better understand the role of fermentation of skin commensals in infectious disease and the importance of the human skin microbiome in skin health. PMID:23405142

Draft genome sequences of 50 MRSA ST5 isolates obtained from a U.S. hospital

USDA-ARS?s Scientific Manuscript database

Methicillin resistant Staphylococcus aureus (MRSA) can be a commensal or pathogen in humans. Pathogenicity and disease are related to the acquisition of mobile genetic elements encoding virulence and antimicrobial resistance genes. Here, we report draft genome sequences for 50 clinical MRSA isolates...

Molecular epidemiology of mastitis pathogens of dairy cattle and comparative relevance to humans.

PubMed

Zadoks, Ruth N; Middleton, John R; McDougall, Scott; Katholm, Jorgen; Schukken, Ynte H

2011-12-01

Mastitis, inflammation of the mammary gland, can be caused by a wide range of organisms, including gram-negative and gram-positive bacteria, mycoplasmas and algae. Many microbial species that are common causes of bovine mastitis, such as Escherichia coli, Klebsiella pneumoniae, Streptococcus agalactiae and Staphylococcus aureus also occur as commensals or pathogens of humans whereas other causative species, such as Streptococcus uberis, Streptococcus dysgalactiae subsp. dysgalactiae or Staphylococcus chromogenes, are almost exclusively found in animals. A wide range of molecular typing methods have been used in the past two decades to investigate the epidemiology of bovine mastitis at the subspecies level. These include comparative typing methods that are based on electrophoretic banding patterns, library typing methods that are based on the sequence of selected genes, virulence gene arrays and whole genome sequencing projects. The strain distribution of mastitis pathogens has been investigated within individual animals and across animals, herds, countries and host species, with consideration of the mammary gland, other animal or human body sites, and environmental sources. Molecular epidemiological studies have contributed considerably to our understanding of sources, transmission routes, and prognosis for many bovine mastitis pathogens and to our understanding of mechanisms of host-adaptation and disease causation. In this review, we summarize knowledge gleaned from two decades of molecular epidemiological studies of mastitis pathogens in dairy cattle and discuss aspects of comparative relevance to human medicine.

Complete Genome Sequence of Staphylococcus haemolyticus Type Strain SGAir0252.

PubMed

Premkrishnan, Balakrishnan N V; Junqueira, Ana Carolina M; Uchida, Akira; Purbojati, Rikky W; Houghton, James N I; Chénard, Caroline; Wong, Anthony; Kolundžija, Sandra; Clare, Megan E; Kushwaha, Kavita K; Panicker, Deepa; Putra, Alexander; Gaultier, Nicolas E; Heinle, Cassie E; Vettath, Vineeth Kodengil; Drautz-Moses, Daniela I; Schuster, Stephan C

2018-05-10

Staphylococcus haemolyticus is a coagulase-negative staphylococcal species that is part of the skin microbiome and an opportunistic human pathogen. The strain SGAir0252 was isolated from tropical air samples collected in Singapore, and its complete genome comprises one chromosome of 2.63 Mb and one plasmid of 41.6 kb. Copyright © 2018 Premkrishnan et al.

An Improved Medium for Growing Staphylococcus aureus Biofilm

DTIC Science & Technology

2012-04-19

implantitis, chronic wound infections , chronic rhinosinusitis, endocarditis , and ocular infections (Archer et al., 2011). In addition, emerging evidence...causes of human bacterial infections , Staphylococcus aureus, a gram positive organism, is a ubiquitous oppor tunistic pathogen that commonly colonizes...resistant to antibiotic therapy. It has been shown that S. aureus biofilms are involved in oste omyelitis; indwelling medical device infections ; and peri

Genotypic and phenotypic characterization of aerosolized bacteria collected from African dust events

DOE PAGES

Wilson, Christina A.; Brigmon, Robin L.; Yeager, Chris; ...

2013-07-31

Twenty-one bacteria were isolated and characterized from air samples collected in Africa and the Caribbean by the United States Geological Survey (USGS). Isolates were selected based on preliminary characterization as possible pathogens. Identification of the bacterial isolates was 25 achieved using 16S rRNA gene sequence analysis, fatty acid methyl esters (FAMEs) profiling, the BIOLOG Microlog® System (carbon substrate assay), and repetitive extragenic palindromic (REP)-PCR analysis. The majority of isolates (18/21) were identified as species of the genus Bacillus. Three isolates were classified within the Bacillus cereus senso lato group, which includes Bacillus anthracis, Bacillus thuringiensis, and Bacillus cereus strains. Onemore » isolate was identified as a Staphylococcus sp., 30 most closely related to species (i.e Staphylococcus kloosii, Staphylococcus warneri) that are commonly associated with human or animal skin, but can also act as opportunistic pathogen. Another isolate was tentatively identified as Tsukamurella inchonensis, a known respiratory pathogen, and was resistant to the ten antibiotics tested including vancomycin.« less

Recent human-to-poultry host jump, adaptation, and pandemic spread of Staphylococcus aureus.

PubMed

Lowder, Bethan V; Guinane, Caitriona M; Ben Zakour, Nouri L; Weinert, Lucy A; Conway-Morris, Andrew; Cartwright, Robyn A; Simpson, A John; Rambaut, Andrew; Nübel, Ulrich; Fitzgerald, J Ross

2009-11-17

The impact of globalization on the emergence and spread of pathogens is an important veterinary and public health issue. Staphylococcus aureus is a notorious human pathogen associated with serious nosocomial and community-acquired infections. In addition, S. aureus is a major cause of animal diseases including skeletal infections of poultry, which are a large economic burden on the global broiler chicken industry. Here, we provide evidence that the majority of S. aureus isolates from broiler chickens are the descendants of a single human-to-poultry host jump that occurred approximately 38 years ago (range, 30 to 63 years ago) by a subtype of the worldwide human ST5 clonal lineage unique to Poland. In contrast to human subtypes of the ST5 radiation, which demonstrate strong geographic clustering, the poultry ST5 clade was distributed in different continents, consistent with wide dissemination via the global poultry industry distribution network. The poultry ST5 clade has undergone genetic diversification from its human progenitor strain by acquisition of novel mobile genetic elements from an avian-specific accessory gene pool, and by the inactivation of several proteins important for human disease pathogenesis. These genetic events have resulted in enhanced resistance to killing by chicken heterophils, reflecting avian host-adaptive evolution. Taken together, we have determined the evolutionary history of a major new animal pathogen that has undergone rapid avian host adaptation and intercontinental dissemination. These data provide a new paradigm for the impact of human activities on the emergence of animal pathogens.

[ABILITY OF STAPHYLOCOCCUS OF VARIOUS STRAINS TO CREATE BIOFILMS AND THEIR EFFECT ON HUMAN BODY CELLS].

PubMed

Kornienko, M A; Kopyltsov, V N; Shevlyagina, N V; Didenko, L V; Lyubasovskaya, L A; Priputnevich, T V; Ilina, E N

2016-01-01

The urgency of the staphylococcus research is due to its ability to cause severe infections: softtissue infections, endocarditis, sepsis, toxic shock syndrome, and food poisoning. Coagulase-positive Staphylococcus aureus is the main infection agent of intrahospital infections. This agent has many factors of pathogenicity, which are well known. Among the coagulase-negative staphylococcus (CNS) strains, S. haemolyticus and S. epidermidis are clinically important, because they cause infections in patients with weak immune system. The mechanisms of the CNS pathogenicity are insufficiently understood. The goal of this work was to evaluate the potential pathogenicity of clinical strains of CNS from their capacity to create biofilms and the character of their interaction with human body cells by the example of the HT-29 cell culture. The research was carried out in laboratory strain S. aureus ATCC 29213 and clinical strains S. haemolyticus SH39, S. epidermidis SE36-1 isolated from the neonatal autopsy materials. The visual tests of biofilm formation by each strain and testing of the impact of the strains on the cell culture HT-29 was carried out in this work. The two species of CNS form biofilms at a higher rate than S. aureus. Upon incubation for 2 h of HT-29 cells with staphylococcus strains tested in this work, adhesion of bacteria on cell surface was observed. The adhesion was most pronounced in case of S. aureus ATCC 29213 and S. haemolyticus SH39. Upon 3 h of incubation with S. aureus ATCC 29213 and S. haemolyticus SH39, destruction of cell HT-29 monolayer was observed. The incubation for 24 h with the 3 strains tested in this work caused complete destruction of cell HT-29 monolayer. The maximal toxic effect on HT-29 cells was inherent in the strain S. haemolyticus SH39. The aggregate of the results obtained in this work indicates the presence of the pathogenicity factors in the strains S. haemolyticus SH39, which require additional research.

PBP-2 Negative Methicillin Resistant Staphylococcus schleiferi Bacteremia from a Prostate Abscess: An Unusual Occurrence

PubMed Central

Merchant, Chandni; Villanueva, Daphne-Dominique; Lalani, Ishan; Eng, Margaret; Kang, Yong

2016-01-01

Staphylococcus schleiferi subsp. schleiferi is a coagulase-negative Staphylococcus which has been described as a pathogen responsible for various nosocomial infections including bacteremia, brain abscess, and infection of intravenous pacemakers. Recently, such bacteria have been described to be found typically on skin and mucosal surfaces. It is also believed to be a part of the preaxillary human flora and more frequently found in men. It is very similar in its pathogenicity with Staphylococcus aureus group and expresses a fibronectin binding protein. Literature on this pathogen reveals that it commonly causes otitis among dogs because of its location in the auditory meatus of canines. Also, it has strong association with pyoderma in dogs. The prime concern with this organism is the antibiotic resistance and relapse even after appropriate treatment. Very rarely, if any, cases have been reported about prostatic abscess (PA) with this microbe. Our patient had a history of recurrent UTIs and subsequent PA resulting in S. schleiferi bacteremia in contrast to gram negative bacteremia commonly associated with UTI. This organism was found to be resistant to methicillin, in spite of being negative for PBP2, which is a rare phenomenon and needs further studies. PMID:27092283

A Bioengineered Nisin Derivative to Control Biofilms of Staphylococcus pseudintermedius

PubMed Central

Field, Des; Gaudin, Noémie; Lyons, Francy; O'Connor, Paula M.; Cotter, Paul D.; Hill, Colin; Ross, R. Paul

2015-01-01

Antibiotic resistance and the shortage of novel antimicrobials are among the biggest challenges facing society. One of the major factors contributing to resistance is the use of frontline clinical antibiotics in veterinary practice. In order to properly manage dwindling antibiotic resources, we must identify antimicrobials that are specifically targeted to veterinary applications. Nisin is a member of the lantibiotic family of antimicrobial peptides that exhibit potent antibacterial activity against many gram-positive bacteria, including human and animal pathogens such as Staphylococcus, Bacillus, Listeria, and Clostridium. Although not currently used in human medicine, nisin is already employed commercially as an anti-mastitis product in the veterinary field. Recently we have used bioengineering strategies to enhance the activity of nisin against several high profile targets, including multi-drug resistant clinical pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) and also against staphylococci and streptococci associated with bovine mastitis. However, newly emerging pathogens such as methicillin resistant Staphylococcus pseudintermedius (MRSP) pose a significant threat in terms of veterinary health and as a reservoir for antibiotic resistance determinants. In this study we created a nisin derivative with enhanced antimicrobial activity against S. pseudintermedius. In addition, the novel nisin derivative exhibits an enhanced ability to impair biofilm formation and to reduce the density of established biofilms. The activities of this peptide represent a significant improvement over that of the wild-type nisin peptide and merit further investigation with a view to their use to treat S. pseudintermedius infections. PMID:25789988

Staphylococcus aureus pathogenesis in diverse host environments

PubMed Central

Balasubramanian, Divya; Harper, Lamia; Shopsin, Bo; Torres, Victor J.

2017-01-01

Abstract Staphylococcus aureus is an eminent human pathogen that can colonize the human host and cause severe life-threatening illnesses. This bacterium can reside in and infect a wide range of host tissues, ranging from superficial surfaces like the skin to deeper tissues such as in the gastrointestinal tract, heart and bones. Due to its multifaceted lifestyle, S. aureus uses complex regulatory networks to sense diverse signals that enable it to adapt to different environments and modulate virulence. In this minireview, we explore well-characterized environmental and host cues that S. aureus responds to and describe how this pathogen modulates virulence in response to these signals. Lastly, we highlight therapeutic approaches undertaken by several groups to inhibit both signaling and the cognate regulators that sense and transmit these signals downstream. PMID:28104617

Antimicrobial Mechanisms of Macrophages and the Immune Evasion Strategies of Staphylococcus aureus

PubMed Central

Flannagan, Ronald S.; Heit, Bryan; Heinrichs, David E.

2015-01-01

Habitually professional phagocytes, including macrophages, eradicate microbial invaders from the human body without overt signs of infection. Despite this, there exist select bacteria that are professional pathogens, causing significant morbidity and mortality across the globe and Staphylococcus aureus is no exception. S. aureus is a highly successful pathogen that can infect virtually every tissue that comprises the human body causing a broad spectrum of diseases. The profound pathogenic capacity of S. aureus can be attributed, in part, to its ability to elaborate a profusion of bacterial effectors that circumvent host immunity. Macrophages are important professional phagocytes that contribute to both the innate and adaptive immune response, however from in vitro and in vivo studies, it is evident that they fail to eradicate S. aureus. This review provides an overview of the antimicrobial mechanisms employed by macrophages to combat bacteria and describes the immune evasion strategies and some representative effectors that enable S. aureus to evade macrophage-mediated killing. PMID:26633519

The Staphylococcus aureus RNome and Its Commitment to Virulence

PubMed Central

Felden, Brice; Vandenesch, François; Bouloc, Philippe; Romby, Pascale

2011-01-01

Staphylococcus aureus is a major human pathogen causing a wide spectrum of nosocomial and community-associated infections with high morbidity and mortality. S. aureus generates a large number of virulence factors whose timing and expression levels are precisely tuned by regulatory proteins and RNAs. The aptitude of bacteria to use RNAs to rapidly modify gene expression, including virulence factors in response to stress or environmental changes, and to survive in a host is an evolving concept. Here, we focus on the recently inventoried S. aureus regulatory RNAs, with emphasis on those with identified functions, two of which are directly involved in pathogenicity. PMID:21423670

Biofilms and the survival of opportunistic pathogens in recycled water

NASA Technical Reports Server (NTRS)

Boyle, M.; Ford, T.; Maki, J. S.; Mitchell, R.

1991-01-01

Microorganisms are likely to develop an organic film on pipes, water reservoirs and filters used for waste water reclamation during extended missions in space. These biofilms can serve to protect and concentrate potentially pathogenic microorganisms. Our investigation has emphasized the survival strategy of opportunistic pathogenic bacteria in distilled water. Pseudomonas aeruginosa and Staphylococcus aureus were used as test organisms. Cultures were incubated at 10 degrees, 25 degrees, and 37 degrees C. No viable Staphylococcus cells were detected after the first week of incubation. P. aeruginosa, however, survived in distilled water up to 5 months at all three temperatures tested. The starved cells were able to form a biofilm layer on stainless steel. The cells exhibited a negative surface charge. The charge may be involved in the adhesion of this bacterium to metal substrata. We are currently investigating the importance of adhesion in the survival of this and other potential human pathogens found in water recycling systems.

Targeting the host-pathogen interface for treatment of Staphylococcus aureus infection.

PubMed

Park, Bonggoo; Liu, George Y

2012-03-01

Recent emergence of methicillin-resistant Staphylococcus aureus both within and outside healthcare settings has accelerated the use of once reserved last line antibiotics such as vancomycin. With increased use of antibiotics, there has been a rapid rise in the rate of resistance development to the anti-MRSA drugs. As the antibiotic pipeline becomes strained, alternative strategies are being sought for future treatment of S. aureus. Here, we review several novel anti-staphylococcal strategies that, unlike conventional antibiotics, do not target essential gene products elaborated by the pathogen. The approaches seek instead to weaken the S. aureus defense by neutralizing its virulence factors or boosting host immunity. Other strategies target commensal bacteria that naturally colonize the human host to inhibit S. aureus colonization. Ultimately, the aim is to shift the balance between host defense and pathogen virulence in favor of inhibition of S. aureus pathogenic activities.

Recent human-to-poultry host jump, adaptation, and pandemic spread of Staphylococcus aureus

PubMed Central

Lowder, Bethan V.; Guinane, Caitriona M.; Ben Zakour, Nouri L.; Weinert, Lucy A.; Conway-Morris, Andrew; Cartwright, Robyn A.; Simpson, A. John; Rambaut, Andrew; Nübel, Ulrich; Fitzgerald, J. Ross

2009-01-01

The impact of globalization on the emergence and spread of pathogens is an important veterinary and public health issue. Staphylococcus aureus is a notorious human pathogen associated with serious nosocomial and community-acquired infections. In addition, S. aureus is a major cause of animal diseases including skeletal infections of poultry, which are a large economic burden on the global broiler chicken industry. Here, we provide evidence that the majority of S. aureus isolates from broiler chickens are the descendants of a single human-to-poultry host jump that occurred approximately 38 years ago (range, 30 to 63 years ago) by a subtype of the worldwide human ST5 clonal lineage unique to Poland. In contrast to human subtypes of the ST5 radiation, which demonstrate strong geographic clustering, the poultry ST5 clade was distributed in different continents, consistent with wide dissemination via the global poultry industry distribution network. The poultry ST5 clade has undergone genetic diversification from its human progenitor strain by acquisition of novel mobile genetic elements from an avian-specific accessory gene pool, and by the inactivation of several proteins important for human disease pathogenesis. These genetic events have resulted in enhanced resistance to killing by chicken heterophils, reflecting avian host-adaptive evolution. Taken together, we have determined the evolutionary history of a major new animal pathogen that has undergone rapid avian host adaptation and intercontinental dissemination. These data provide a new paradigm for the impact of human activities on the emergence of animal pathogens. PMID:19884497

Staphylococcus aureus golden pigment impairs neutrophil killing and promotes virulence through its antioxidant activity.

PubMed

Liu, George Y; Essex, Anthony; Buchanan, John T; Datta, Vivekanand; Hoffman, Hal M; Bastian, John F; Fierer, Joshua; Nizet, Victor

2005-07-18

Golden color imparted by carotenoid pigments is the eponymous feature of the human pathogen Staphylococcus aureus. Here we demonstrate a role of this hallmark phenotype in virulence. Compared with the wild-type (WT) bacterium, a S. aureus mutant with disrupted carotenoid biosynthesis is more susceptible to oxidant killing, has impaired neutrophil survival, and is less pathogenic in a mouse subcutaneous abscess model. The survival advantage of WT S. aureus over the carotenoid-deficient mutant is lost upon inhibition of neutrophil oxidative burst or in human or murine nicotinamide adenine dinucleotide phosphate oxidase-deficient hosts. Conversely, heterologous expression of the S. aureus carotenoid in the nonpigmented Streptococcus pyogenes confers enhanced oxidant and neutrophil resistance and increased animal virulence. Blocking S. aureus carotenogenesis increases oxidant sensitivity and decreases whole-blood survival, suggesting a novel target for antibiotic therapy.

Evolution of Staphylococcus aureus during human colonization and infection.

PubMed

Fitzgerald, J Ross

2014-01-01

The diversification of bacterial pathogens during infection is central to their capacity to adapt to different anatomical niches, evade the host immune system, and overcome therapeutic challenges. For example, antimicrobial treatment may fail due to the development of resistance during infection, which is often accompanied by transition to a less virulent state during chronic, persistent infection. In this review, the adaptation of the major human pathogen Staphylococcus aureus to its host environment during infection will be discussed, particularly in the context of new sequencing technologies which have opened a gateway towards understanding of the molecular processes underlying those adaptations. We now have the capacity to address previously intractable questions regarding bacterial diversification during infection which will ultimately lead to enhanced understanding of pathogenesis and the nature of epidemics, and will inform the design of effective therapeutic measures. Copyright © 2013 Elsevier B.V. All rights reserved.

Coagulase-negative staphylococci as reservoirs of genes facilitating MRSA infection

PubMed Central

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. PMID:23165978

The Food Production Environment and the Development of Antimicrobial Resistance in Human Pathogens of Animal Origin.

PubMed

Lekshmi, Manjusha; Ammini, Parvathi; Kumar, Sanath; Varela, Manuel F

2017-03-14

Food-borne pathogens are a serious human health concern worldwide, and the emergence of antibiotic-resistant food pathogens has further confounded this problem. Once-highly-efficacious antibiotics are gradually becoming ineffective against many important pathogens, resulting in severe treatment crises. Among several reasons for the development and spread of antimicrobial resistance, their overuse in animal food production systems for purposes other than treatment of infections is prominent. Many pathogens of animals are zoonotic, and therefore any development of resistance in pathogens associated with food animals can spread to humans through the food chain. Human infections by antibiotic-resistant pathogens such as Campylobacter spp., Salmonella spp., Escherichia coli and Staphylococcus aureus are increasing. Considering the human health risk due to emerging antibiotic resistance in food animal-associated bacteria, many countries have banned the use of antibiotic growth promoters and the application in animals of antibiotics critically important in human medicine. Concerted global efforts are necessary to minimize the use of antimicrobials in food animals in order to control the development of antibiotic resistance in these systems and their spread to humans via food and water.

Scabies mites alter the skin microbiome and promote growth of opportunistic pathogens in a porcine model.

PubMed

Swe, Pearl M; Zakrzewski, Martha; Kelly, Andrew; Krause, Lutz; Fischer, Katja

2014-01-01

The resident skin microbiota plays an important role in restricting pathogenic bacteria, thereby protecting the host. Scabies mites (Sarcoptes scabiei) are thought to promote bacterial infections by breaching the skin barrier and excreting molecules that inhibit host innate immune responses. Epidemiological studies in humans confirm increased incidence of impetigo, generally caused by Staphylococcus aureus and Streptococcus pyogenes, secondary to the epidermal infestation with the parasitic mite. It is therefore possible that mite infestation could alter the healthy skin microbiota making way for the opportunistic pathogens. A longitudinal study to test this hypothesis in humans is near impossible due to ethical reasons. In a porcine model we generated scabies infestations closely resembling the disease manifestation in humans and investigated the scabies associated changes in the skin microbiota over the course of a mite infestation. In a 21 week trial, skin scrapings were collected from pigs infected with S. scabies var. suis and scabies-free control animals. A total of 96 skin scrapings were collected before, during infection and after acaricide treatment, and analyzed by bacterial 16S rDNA tag-encoded FLX-titanium amplicon pyrosequencing. We found significant changes in the epidermal microbiota, in particular a dramatic increase in Staphylococcus correlating with the onset of mite infestation in animals challenged with scabies mites. This increase persisted beyond treatment from mite infection and healing of skin. Furthermore, the staphylococci population shifted from the commensal S. hominis on the healthy skin prior to scabies mite challenge to S. chromogenes, which is increasingly recognized as being pathogenic, coinciding with scabies infection in pigs. In contrast, all animals in the scabies-free cohort remained relatively free of Staphylococcus throughout the trial. This is the first experimental in vivo evidence supporting previous assumptions that establishment of pathogens follow scabies infection. Our findings provide an explanation for a biologically important aspect of the disease pathogenesis. The methods developed from this pig trial will serve as a guide to analyze human clinical samples. Studies building on this will offer implications for development of novel intervention strategies against the mites and the secondary infections.

Scabies Mites Alter the Skin Microbiome and Promote Growth of Opportunistic Pathogens in a Porcine Model

PubMed Central

Swe, Pearl M.; Zakrzewski, Martha; Kelly, Andrew; Krause, Lutz; Fischer, Katja

2014-01-01

Background The resident skin microbiota plays an important role in restricting pathogenic bacteria, thereby protecting the host. Scabies mites (Sarcoptes scabiei) are thought to promote bacterial infections by breaching the skin barrier and excreting molecules that inhibit host innate immune responses. Epidemiological studies in humans confirm increased incidence of impetigo, generally caused by Staphylococcus aureus and Streptococcus pyogenes, secondary to the epidermal infestation with the parasitic mite. It is therefore possible that mite infestation could alter the healthy skin microbiota making way for the opportunistic pathogens. A longitudinal study to test this hypothesis in humans is near impossible due to ethical reasons. In a porcine model we generated scabies infestations closely resembling the disease manifestation in humans and investigated the scabies associated changes in the skin microbiota over the course of a mite infestation. Methodology/Principal Findings In a 21 week trial, skin scrapings were collected from pigs infected with S. scabies var. suis and scabies-free control animals. A total of 96 skin scrapings were collected before, during infection and after acaricide treatment, and analyzed by bacterial 16S rDNA tag-encoded FLX-titanium amplicon pyrosequencing. We found significant changes in the epidermal microbiota, in particular a dramatic increase in Staphylococcus correlating with the onset of mite infestation in animals challenged with scabies mites. This increase persisted beyond treatment from mite infection and healing of skin. Furthermore, the staphylococci population shifted from the commensal S. hominis on the healthy skin prior to scabies mite challenge to S. chromogenes, which is increasingly recognized as being pathogenic, coinciding with scabies infection in pigs. In contrast, all animals in the scabies-free cohort remained relatively free of Staphylococcus throughout the trial. Conclusions/Significance This is the first experimental in vivo evidence supporting previous assumptions that establishment of pathogens follow scabies infection. Our findings provide an explanation for a biologically important aspect of the disease pathogenesis. The methods developed from this pig trial will serve as a guide to analyze human clinical samples. Studies building on this will offer implications for development of novel intervention strategies against the mites and the secondary infections. PMID:24875186

Prevalence and antimicrobial resistance profile of Staphylococcus in dairy farms, abattoir and humans in Addis Ababa, Ethiopia.

PubMed

Beyene, Takele; Hayishe, Halefom; Gizaw, Fikru; Beyi, Ashenafi Feyisa; Abunna, Fufa; Mammo, Bedaso; Ayana, Dinka; Waktole, Hika; Abdi, Reta Duguma

2017-04-28

Staphylococcus species cause mastitis and wound infection in livestock and food poisoning in humans through ingestion of contaminated foods, including meat and dairy products. They are evolving pathogens in that they readily acquire drug resistance, and multiple drug-resistant (MDR) isolates are increasing in human and veterinary healthcare. Therefore, this study was conducted to evaluate the prevalence of Staphylococci and their drug resistance in dairy farms and abattoir settings of Addis Ababa. In this cross-sectional study, 193 samples of milk, meat, equipment and humans working in the dairy farms and abattoir were collected (dairy farms = 72 and abattoir sources = 121). Staphylococcus isolation and identification at the species level was done according to ISO-6888-3 using biochemical characteristics. An antimicrobial susceptibility test was conducted for 43 of the isolates using 15 antimicrobial agents commonly used for humans and livestock by the Kirby Bauer disk diffusion method following CLSI guidelines. Staphylococcus organism were isolated from 92 (47.7%) of the total 193 samples, 50% in the dairy farms and 46.3% in the abattoir. The isolated species were S. aureus (n = 31; 16.1%), S. intermedius (n = 21; 10.9%), S. hyicus (n = 16; 8.3%), and coagulase negative Staphylococcus (CNS) (n = 24; 12.4%). Gentamycin was effective drug as all isolates (n = 43; 100%) were susceptible to it and followed by kanamycin (n = 39; 90.7%). However, the majority of the isolates showed resistance to penicillin-G (95.3%), nalidixic acid (88.4%), cloxacillin (79.1%), vancomycin (65.1%) and cefoxitin (55.8%). Of the 15 S. aureus tested for drug susceptibility, 73.3% of them were phenotypically resistant to vancomycin (VRSA) and all of the 15 isolates showed multi-drug resistance (MDR) to >3 drugs. Also, all of the tested CNS (100%), S. hyicus (100%) and the majority of S. intermedius isolates (88.9%) developed MDR. Alarmingly, the Staphylococcus isolates circulating in the dairy farms and abattoir in the study area harbor MDR. High level of Staphylococcus species isolation from personnel and equipment besides food (meat and milk) samples in dairy farms and abattoir settings reveals that the hygiene practice in the dairy farm and abattoir is substandard. Prudent drug use and improved hygienic practice is recommended in the dairy farms and abattoir to safeguard the public from the risk of acquiring infections and MDR pathogenic Staphylococcus.

Staphylococcus haemolyticus as a potential producer of biosurfactants with antimicrobial, anti-adhesive and synergistic properties.

PubMed

Rossi, C C; Santos-Gandelman, J F; Barros, E M; Alvarez, V M; Laport, M S; Giambiagi-deMarval, M

2016-09-01

Staphylococcus haemolyticus is an opportunistic human pathogen that usually gains entry into the host tissue in association with medical device contamination. Biofilm formation is a key factor for the establishment of this bacterium and its arrangement and dynamics can be influenced by the synthesis of biosurfactants. Biosurfactants are structurally diverse amphiphilic molecules with versatile biotechnological applications, but information on their production by staphylococci is still scarce. In this work, two Staph. haemolyticus strains, showing high potential for biosurfactant production - as observed by four complementary methods - were investigated. Biosurfactant extracts were produced and studied for their capacity to inhibit the growth and biofilm formation by other bacterial human pathogens. The biosurfactant produced by the one of the strains inhibited the growth of most bacteria tested and subinhibitory concentrations of the biosurfactant were able to decrease biofilm formation and showed synergistic effects with tetracycline. Because these results were also positive when the biosurfactants were tested against the producing strains, it is likely that biosurfactant production by Staph. haemolyticus may be an unexplored virulence factor, important for competition and biofilm formation by the bacterium, in addition to the biotechnological potential. This work is the first to show the production of biosurfactants by Staphylococcus haemolyticus strains. Extracts showed antimicrobial, anti-adhesive and synergistic properties against a variety of relevant human pathogens, including the producing strains. In addition to the biotechnological potential, biosurfactants produced by Staph. haemolyticus are potentially undescribed virulence determinants in their producing strains. © 2016 The Society for Applied Microbiology.

Escherichia coli and selected veterinary and zoonotic pathogens isolated from environmental sites in companion animal veterinary hospitals in southern Ontario.

PubMed

Murphy, Colleen P; Reid-Smith, Richard J; Boerlin, Patrick; Weese, J Scott; Prescott, John F; Janecko, Nicol; Hassard, Lori; McEwen, Scott A

2010-09-01

Hospital-based infection control in veterinary medicine is emerging and the role of the environment in hospital-acquired infections (HAI) in veterinary hospitals is largely unknown. This study was initiated to determine the recovery of Escherichia coli and selected veterinary and zoonotic pathogens from the environments of 101 community veterinary hospitals. The proportion of hospitals with positive environmental swabs were: E. coli--92%, Clostridium difficile--58%, methicillin-resistant Staphylococcus aureus (MRSA)--9%, CMY-2 producing E. coli--9%, methicillin-resistant Staphylococcus pseudintermedius--7%, and Salmonella--2%. Vancomycin-resistant Enterococcus spp., canine parvovirus, and feline calicivirus were not isolated. Prevalence of antimicrobial resistance in E. coli isolates was low. Important potential veterinary and human pathogens were recovered including Canadian epidemic strains MRSA-2 and MRSA-5, and C. difficile ribotype 027. There is an environmental reservoir of pathogens in veterinary hospitals; therefore, additional studies are required to characterize risk factors associated with HAI in companion animals, including the role of the environment.

Draft genome sequences of 9 LA-MRSA ST5 isolates from humans with long term swine contact

USDA-ARS?s Scientific Manuscript database

Humans have been found to harbor livestock associated methicillin resistant Staphylococcus aureus (LA-MRSA) isolates. LA-MRSA are considered adapted to colonizing livestock and less pathogenic than their hospital and community counterparts. Here, we present 9 LA-MRSA ST5 isolates from veterinarians ...

Novel bacteriophage lysin with broad lytic activity protects against mixed infection by Streptococcus pyogenes and methicillin-resistant Staphylococcus aureus.

PubMed

Gilmer, Daniel B; Schmitz, Jonathan E; Euler, Chad W; Fischetti, Vincent A

2013-06-01

Methicillin-resistant Staphylococcus aureus (MRSA) and Streptococcus pyogenes (group A streptococcus [GrAS]) cause serious and sometimes fatal human diseases. They are among the many Gram-positive pathogens for which resistance to leading antibiotics has emerged. As a result, alternative therapies need to be developed to combat these pathogens. We have identified a novel bacteriophage lysin (PlySs2), derived from a Streptococcus suis phage, with broad lytic activity against MRSA, vancomycin-intermediate S. aureus (VISA), Streptococcus suis, Listeria, Staphylococcus simulans, Staphylococcus epidermidis, Streptococcus equi, Streptococcus agalactiae (group B streptococcus [GBS]), S. pyogenes, Streptococcus sanguinis, group G streptococci (GGS), group E streptococci (GES), and Streptococcus pneumoniae. PlySs2 has an N-terminal cysteine-histidine aminopeptidase (CHAP) catalytic domain and a C-terminal SH3b binding domain. It is stable at 50 °C for 30 min, 37 °C for >24 h, 4°C for 15 days, and -80 °C for >7 months; it maintained full activity after 10 freeze-thaw cycles. PlySs2 at 128 μg/ml in vitro reduced MRSA and S. pyogenes growth by 5 logs and 3 logs within 1 h, respectively, and exhibited a MIC of 16 μg/ml for MRSA. A single, 2-mg dose of PlySs2 protected 92% (22/24) of the mice in a bacteremia model of mixed MRSA and S. pyogenes infection. Serially increasing exposure of MRSA and S. pyogenes to PlySs2 or mupirocin resulted in no observed resistance to PlySs2 and resistance to mupirocin. To date, no other lysin has shown such notable broad lytic activity, stability, and efficacy against multiple, leading, human bacterial pathogens; as such, PlySs2 has all the characteristics to be an effective therapeutic.

Pathogenic Mechanisms and Host Interactions in Staphylococcus epidermidis Device-Related Infection.

PubMed

Sabaté Brescó, Marina; Harris, Llinos G; Thompson, Keith; Stanic, Barbara; Morgenstern, Mario; O'Mahony, Liam; Richards, R Geoff; Moriarty, T Fintan

2017-01-01

Staphylococcus epidermidis is a permanent member of the normal human microbiota, commonly found on skin and mucous membranes. By adhering to tissue surface moieties of the host via specific adhesins, S. epidermidis is capable of establishing a lifelong commensal relationship with humans that begins early in life. In its role as a commensal organism, S. epidermidis is thought to provide benefits to human host, including out-competing more virulent pathogens. However, largely due to its capacity to form biofilm on implanted foreign bodies, S. epidermidis has emerged as an important opportunistic pathogen in patients receiving medical devices. S. epidermidis causes approximately 20% of all orthopedic device-related infections (ODRIs), increasing up to 50% in late-developing infections. Despite this prevalence, it remains underrepresented in the scientific literature, in particular lagging behind the study of the S. aureus . This review aims to provide an overview of the interactions of S. epidermidis with the human host, both as a commensal and as a pathogen. The mechanisms retained by S. epidermidis that enable colonization of human skin as well as invasive infection, will be described, with a particular focus upon biofilm formation. The host immune responses to these infections are also described, including how S. epidermidis seems to trigger low levels of pro-inflammatory cytokines and high levels of interleukin-10, which may contribute to the sub-acute and persistent nature often associated with these infections. The adaptive immune response to S. epidermidis remains poorly described, and represents an area which may provide significant new discoveries in the coming years.

Intracellular staphylococcus aureus: Live-in and let die

PubMed Central

Fraunholz, Martin; Sinha, Bhanu

2012-01-01

Staphylococcus aureus uses a plethora of virulence factors to accommodate a diversity of niches in its human host. Aside from the classical manifestations of S. aureus-induced diseases, the pathogen also invades and survives within mammalian host cells.The survival strategies of the pathogen are as diverse as strains or host cell types used. S. aureus is able to replicate in the phagosome or freely in the cytoplasm of its host cells. It escapes the phagosome of professional and non-professional phagocytes, subverts autophagy, induces cell death mechanisms such as apoptosis and pyronecrosis, and even can induce anti-apoptotic programs in phagocytes. The focus of this review is to present a guide to recent research outlining the variety of intracellular fates of S. aureus. PMID:22919634

Cloning and sequencing of Staphylococcus aureus murC, a gene essential for cell wall biosynthesis.

PubMed

Lowe, A M; Deresiewicz, R L

1999-01-01

Staphylococcus aureus is a major human pathogen that is increasingly resistant to clinically useful antimicrobial agents. While screening for S. aureus genes expressed during mammalian infection, we isolated murC. This gene encodes UDP-N-acetylmuramoyl-L-alanine synthetase, an enzyme essential for cell wall biosynthesis in a number of bacteria. S. aureus MurC has a predicted mass 49,182 Da and complements the temperature-sensitive murC mutation of E. coli ST222. Sequence data on the DNA flanking staphylococcal murC suggests that the local gene organization there parallels that found in B. subtilis, but differs from that found in gram-negative bacterial pathogens. MurC proteins represent promising targets for broad spectrum antimicrobial drug development.

Complete genome sequence of community-associated methicillin-resistant Staphylococcus aureus (strain USA400-0051), a prototype of the USA400 clone

PubMed Central

Côrtes, Marina Farrel; Costa, Maiana OC; Lima, Nicholas CB; Souza, Rangel C; Almeida, Luiz GP; Guedes, Luciane Prioli Ciapina; Vasconcelos, Ana TR; Nicolás, Marisa F; Figueiredo, Agnes MS

2017-01-01

Staphylococcus aureus subsp. aureus, commonly referred as S. aureus, is an important bacterial pathogen frequently involved in hospital- and community-acquired infections in humans, ranging from skin infections to more severe diseases such as pneumonia, bacteraemia, endocarditis, osteomyelitis, and disseminated infections. Here, we report the complete closed genome sequence of a community-acquired methicillin-resistant S. aureus strain, USA400-0051, which is a prototype of the USA400 clone. PMID:29091141

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

SCC mec typing and antimicrobial resistance of methicillin-resistant Staphylococcus aureus (MRSA) from pigs of Northeast India.

PubMed

Rajkhowa, S; Sarma, D K; Pegu, S R

2016-12-01

Staphylococcus aureus is one of the most important pathogens of both humans and animal. Methicillin-resistant Staphylococcus aureus (MRSA) is an important human pathogen that causes serious infections both in hospitals and communities due to its multidrug resistance tendency. This study was undertaken to characterize the MRSA isolates from pigs and to determine the antimicrobial resistance of these isolates. Forty nine MRSA strains (one strain per positive pig) isolated from pigs of Northeast India were characterized by SCCmec typing and antimicrobial resistance. The overall prevalence of MRSA was 7.02 % with the highest prevalence recorded in pigs aged 1-3 months (P = 0.001) and in nasal samples (P = 0.005). Two SCC mec types (type III and V) were found in Indian pigs with predominance of type V. All isolates were resistant to penicillin. Seventeen resistance groups were observed where 87.75 % isolates showed multidrug resistance (showed resistance to three or more classes of antimicrobials). The most predominant resistance pattern observed was Oxytetracycline + Penicillin + Sulfadiazine + Tetracycline accounting 12.24 % of the isolates. The present study contributes to the understanding of characteristics and antimicrobial resistance of porcine MRSA isolates which in turn will help in devising strategy for the control of this pathogen. Findings of the study also throw light on multidrug resistance MRSA and emphasize the need for judicious use of antimicrobials in animal practice.

Molecular mechanisms of mucocutaneous immunity against Candida and Staphylococcus species.

PubMed

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

2012-11-01

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

Neither non-toxigenic Staphylococcus aureus nor commensal S. epidermidi activates NLRP3 inflammasomes in human conjunctival goblet cells

PubMed Central

Li, Dayu; Hodges, Robin R; Bispo, Paulo; Gilmore, Michael S; Gregory-Ksander, Meredith; Dartt, Darlene A

2017-01-01

Purpose The conjunctiva is a wet mucosal surface surrounding the cornea that is continuously exposed to pathogens. Nevertheless, persistent inflammation is not observed. We examined if the NOD-like receptor pyrin domain 3 (NLRP3) inflammasome functions as a sensor that distinguishes commensal and non-pathogenic bacteria from pathogenic bacteria in human conjunctival goblet cells. Methods Goblet cells were grown from human conjunctiva and co-cultured with commensal Staphylococcus epidermidis, isogenic non-toxigenic S. aureus ACL135 and as a control toxigenic S. aureus RN6390. Activation of the NLRP3 inflammasome was determined by measuring changes in NF-κB activity, expression of pro-interleukin (IL)-1β and NLRP3, activation of caspase-1 and secretion of mature IL-1β. Goblet cell mucin secretion was measured in parallel. Results While all three strains of bacteria were able to bind to goblet cells, neither commensal S. epidermidis nor isogenic non-toxigenic S. aureus ACL135 was able to stimulate an increase in (1) NF-κB activity, (2) pro-IL-1β and NLRP3 expression, (3) caspase-1 activation, (4) mature IL-1β and (5) mucin secretion. Toxigenic S. aureus, the positive control, increased these values: knockdown of NLRP3 with small interfering RNA (siRNA) completely abolished the toxigenic S. aureus-induced expression of pro-IL-1β and secretion of mature IL-1β. Conclusions We conclude that NLRP3 serves as a sensor capable of discriminating commensal and non-pathogenic bacteria from pathogenic bacteria in conjunctival goblet cells, and that activation of the NLRP3 inflammasome induced by pathogenic bacteria mediates secretion of both mature IL-1β and large secretory mucins from these cells. PMID:29354725

Filaments in curved streamlines: rapid formation of Staphylococcus aureus biofilm streamers

NASA Astrophysics Data System (ADS)

Kim, Minyoung Kevin; Drescher, Knut; Pak, On Shun; Bassler, Bonnie L.; Stone, Howard A.

2014-06-01

Biofilms are surface-associated conglomerates of bacteria that are highly resistant to antibiotics. These bacterial communities can cause chronic infections in humans by colonizing, for example, medical implants, heart valves, or lungs. Staphylococcus aureus, a notorious human pathogen, causes some of the most common biofilm-related infections. Despite the clinical importance of S. aureus biofilms, it remains mostly unknown how physical effects, in particular flow, and surface structure influence biofilm dynamics. Here we use model microfluidic systems to investigate how environmental factors, such as surface geometry, surface chemistry, and fluid flow affect biofilm development of S. aureus. We discovered that S. aureus rapidly forms flow-induced, filamentous biofilm streamers, and furthermore if surfaces are coated with human blood plasma, streamers appear within minutes and clog the channels more rapidly than if the channels are uncoated. To understand how biofilm streamer filaments reorient in flows with curved streamlines to bridge the distances between corners, we developed a mathematical model based on resistive force theory of slender filaments. Understanding physical aspects of biofilm formation of S. aureus may lead to new approaches for interrupting biofilm formation of this pathogen.

Filaments in curved flow: Rapid formation of Staphylococcus aureus biofilm streamers

NASA Astrophysics Data System (ADS)

Kim, Min Young; Drescher, Knut; Pak, On Shun; Bassler, Bonnie L.; Stone, Howard A.

2014-03-01

Biofilms are surface-associated conglomerates of bacteria that are highly resistant to antibiotics. These bacterial communities can cause chronic infections in humans by colonizing, for example, medical implants, heart valves, or lungs. Staphylococcus aureus, a notorious human pathogen, causes some of the most common biofilm-related infections. Despite the clinical importance of S. aureus biofilms, it remains mostly unknown how physical effects, in particular flow, and surface structure influence biofilm dynamics. Here we use model microfluidic systems to investigate how environmental factors, such as surface geometry, surface chemistry, and fluid flow affect biofilm development in S. aureus.We discovered that S. aureus rapidly forms flow-induced, filamentous biofilm streamers, and furthermore if surfaces are coated with human blood plasma, streamers appear within minutes and clog the channels more rapidly than if the channels are uncoated. To understand how biofilm streamer filaments reorient in curved flow to bridge the distances between corners, we developed a mathematical model based on resistive force theory and slender filaments. Understanding physical aspects of biofilm formation in S. aureus may lead to new approaches for interrupting biofilm formation of this pathogen.

Inhibition of staphyloxanthin biosynthesis in Staphylococcus aureus by rhodomyrtone, a novel antibiotic candidate.

PubMed

Leejae, Sukanlaya; Hasap, Laila; Voravuthikunchai, Supayang Piyawan

2013-03-01

Staphyloxanthin is the eponymous feature of the human pathogen Staphylococcus aureus, and the pigment promotes resistance to reactive oxygen species and host neutrophil-based killing. To probe the possible use of rhodomyrtone isolated from Rhodomyrtus tomentosa (Aiton) Hassk. leaves to inhibit pigment production in S. aureus, experiments were carried out to compare pigment production and the susceptibility of rhodomyrtone-treated S. aureus and untreated cells to oxidants in vitro. In addition, we observed the innate immune clearance of S. aureus after incubation with rhodomyrtone using an ex vivo assay system - human whole-blood survival. The results indicated that rhodomyrtone-treated S. aureus exhibited reduced pigmentation, and that rhodomyrtone treatment led to a dose-dependent increase in the susceptibility of the pathogen to H(2)O(2) and singlet oxygen killing. Consequently, the survival ability of the treated organisms decreased in freshly isolated human whole blood due to less carotenoid pigment to act as an antioxidant scavenger. Rhodomyrtone may be acting via effects on DnaK and/or σ(B), resulting in many additional effects on bacterial virulence.

Upregulation and Identification of Antibiotic Activity of a Marine-Derived Streptomyces sp. via Co-Cultures with Human Pathogens.

PubMed

Sung, Anne A; Gromek, Samantha M; Balunas, Marcy J

2017-08-11

Marine natural product drug discovery has begun to play an important role in the treatment of disease, with several recently approved drugs. In addition, numerous microbial natural products have been discovered from members of the order Actinomycetales, particularly in the genus Streptomyces , due to their metabolic diversity for production of biologically active secondary metabolites. However, many secondary metabolites cannot be produced under laboratory conditions because growth conditions in flask culture differ from conditions in the natural environment. Various experimental conditions (e.g., mixed fermentation) have been attempted to increase yields of previously described metabolites, cause production of previously undetected metabolites, and increase antibiotic activity. Adult ascidians-also known as tunicates-are sessile marine invertebrates, making them vulnerable to predation and therefore are hypothesized to use host-associated bacteria that produce biologically active secondary metabolites for chemical defense. A marine-derived Streptomyces sp. strain PTY087I2 was isolated from a Panamanian tunicate and subsequently co-cultured with human pathogens including Bacillus subtilis , methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-resistant Staphylococcus aureus (MRSA), and Pseudomonas aeruginosa , followed by extraction. Co-culture of Streptomyces sp. PTY087I2 with each of these human pathogens resulted in increased production of three antibiotics: granaticin, granatomycin D, and dihydrogranaticin B, as well as several analogues seen via molecular networking. In addition, co-cultures resulted in strongly enhanced biological activity against the Gram positive human pathogens used in these experiments. Expanded utilization of co-culture experiments to allow for competitive interactions may enhance metabolite production and further our understanding of these microbial interactions.

Antibacterial activity of some medicinal plants against selected human pathogenic bacteria

PubMed Central

Khan, Usman Ali; Niaz, Zeeshan; Qasim, Muhammad; Khan, Jafar; Tayyaba; Rehman, Bushra

2013-01-01

Medicinal plants are traditionally used for the treatment of human infections. The present study was undertaken to investigate Bergenia ciliata, Jasminum officinale, and Santalum album for their potential activity against human bacterial pathogens. B. ciliata, J. officinale, and S. album extracts were prepared in cold and hot water. The activity of plant extracts and selected antibiotics was evaluated against five bacterial pathogens including Staphylococcus aureus, Bacillus subtilis, Proteus vulgaris, Pseudomonas aeruginosa, and Escherichia coli using agar well diffusion method. Among the three medicinal plants, B. ciliata extracts displayed potential activity against bacterial pathogens. Cold water extract of Bergenia ciliate showed the highest activity against B. subtilis, which is comparable with a zone of inhibition exhibited by ceftriaxone and erythromycin. J. officinale and S. album extracts demonstrated variable antibacterial activity. Further studies are needed to explore the novel antibacterial bioactive molecules. PMID:24294497

Toxin-Antitoxin Systems in Clinical Pathogens

PubMed Central

Fernández-García, Laura; Blasco, Lucia; Lopez, Maria; Bou, German; García-Contreras, Rodolfo; Wood, Thomas; Tomas, María

2016-01-01

Toxin-antitoxin (TA) systems are prevalent in bacteria and archaea. Although not essential for normal cell growth, TA systems are implicated in multiple cellular functions associated with survival under stress conditions. Clinical strains of bacteria are currently causing major human health problems as a result of their multidrug resistance, persistence and strong pathogenicity. Here, we present a review of the TA systems described to date and their biological role in human pathogens belonging to the ESKAPE group (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp.) and others of clinical relevance (Escherichia coli, Burkholderia spp., Streptococcus spp. and Mycobacterium tuberculosis). Better understanding of the mechanisms of action of TA systems will enable the development of new lines of treatment for infections caused by the above-mentioned pathogens. PMID:27447671

Evolutionarily distinct bacteriophage endolysins featuring conserved peptidoglycan cleavage sites protect mice from MRSA infection

USDA-ARS?s Scientific Manuscript database

Staphylococcus aureus is a Gram-positive pathogen relevant for both human and animal health. With multi-drug resistant S. aureus strains becoming increasingly prevalent, alternative therapeutics are urgently needed. Bacteriophage endolysins (peptidoglycan hydrolases, PGH) are capable of killing Gra...

Antibiotic-resistant bacteria: prevalence in food and inactivation by food compatible compounds and plant extracts

USDA-ARS?s Scientific Manuscript database

Foodborne antibiotic-resistant pathogenic bacteria such as Campylobacter jejuni, Bacillus cereus, Clostridium perfringens, Escherichia coli, Salmonella enterica, Staphylococcus aureus, and Vibrio cholerae can adversely affect animal and human health, but a better understanding of the factors involve...

Streptococcus uberis and Staphylococcus aureus forefoot and blood stream co-infection in a haemodialysis patient: a case report.

PubMed

Valentiny, Christine; Dirschmid, Harald; Lhotta, Karl

2015-05-28

Streptococcus uberis, the most frequent cause of mastitis in lactating cows, is considered non-pathogenic for humans. Only a few case reports have described human infections with this microorganism, which is notoriously difficult to identify. We report the case of a 75-year-old male haemodialysis patient, who developed a severe foot infection with osteomyelitis and bacteraemia. Both Streptococcus uberis and Staphylococcus aureus were identified in wound secretion and blood samples using mass spectrometry. The presence of Streptococcus uberis was confirmed by superoxide dismutase A sequencing. The patient recovered after amputation of the forefoot and antibiotic treatment with ampicillin/sulbactam. He had probably acquired the infection while walking barefoot on cattle pasture land. This is the first case report of a human infection with Streptococcus uberis with identification of the microorganism using modern molecular technology. We propose that Staphylococcus aureus co-infection was a prerequisite for deep wound and bloodstream infection with Streptococcus uberis.

Occurrence and Persistence of Bacterial Pathogens and Indicator Organisms in Beach Sand along the California Coast

PubMed Central

Yamahara, Kevan M.; Sassoubre, Lauren M.; Goodwin, Kelly D.

2012-01-01

This report documents the presence of fecal indicators and bacterial pathogens in sand at 53 California marine beaches using both culture-dependent and -independent (PCR and quantitative PCR [QPCR]) methods. Fecal indicator bacteria were widespread in California beach sand, with Escherichia coli and enterococci detected at 68% and 94% of the beaches surveyed, respectively. Somatic coliphages and a Bacteroidales human-specific fecal marker were detected at 43% and 13% of the beaches, respectively. Dry sand samples from almost 30% of the beaches contained at least one of the following pathogens: Salmonella spp., Campylobacter spp., Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus (MRSA), which were detected at 15%, 13%, 14%, and 3% of tested beaches, respectively. Fecal indicators and pathogens were poorly correlated to one another and to land cover. Sands were dry at the time of collection, and those with relatively high moisture tended to have higher concentrations or a more frequent occurrence of both indicators and pathogens. Using culture-dependent assays, fecal indicators decayed faster than pathogens in microcosm experiments using unaltered beach sand seeded with sewage and assessed by culture-dependent assays. The following order of persistence was observed (listed from most to least persistent): Campylobacter > Salmonella > somatic coliphages > enterococci > E. coli > F+ phages. In contrast, pathogens decayed faster than fecal indicators in culture-independent assays: enterococci > Bacteroidales human-specific marker > Salmonella > Campylobacter. Microcosm experiments demonstrated that both indicators and pathogens were mobilized by wetting with seawater. Decay rates measured by QPCR were lower than those measured with culture-dependent methods. Enterococcal persistence and possible growth were observed for wetted microcosms relative to unwetted controls. PMID:22247142

Escherichia coli and selected veterinary and zoonotic pathogens isolated from environmental sites in companion animal veterinary hospitals in southern Ontario

PubMed Central

Murphy, Colleen P.; Reid-Smith, Richard J.; Boerlin, Patrick; Weese, J. Scott; Prescott, John F.; Janecko, Nicol; Hassard, Lori; McEwen, Scott A.

2010-01-01

Hospital-based infection control in veterinary medicine is emerging and the role of the environment in hospital-acquired infections (HAI) in veterinary hospitals is largely unknown. This study was initiated to determine the recovery of Escherichia coli and selected veterinary and zoonotic pathogens from the environments of 101 community veterinary hospitals. The proportion of hospitals with positive environmental swabs were: E. coli — 92%, Clostridium difficile — 58%, methicillin-resistant Staphylococcus aureus (MRSA) — 9%, CMY-2 producing E. coli — 9%, methicillin-resistant Staphylococcus pseudintermedius — 7%, and Salmonella — 2%. Vancomycin-resistant Enterococcus spp., canine parvovirus, and feline calicivirus were not isolated. Prevalence of antimicrobial resistance in E. coli isolates was low. Important potential veterinary and human pathogens were recovered including Canadian epidemic strains MRSA-2 and MRSA-5, and C. difficile ribotype 027. There is an environmental reservoir of pathogens in veterinary hospitals; therefore, additional studies are required to characterize risk factors associated with HAI in companion animals, including the role of the environment. PMID:21119862

A retrospective audit of bacterial culture results of donated human milk in Perth, Western Australia.

PubMed

Almutawif, Yahya; Hartmann, Benjamin; Lloyd, Megan; Erber, Wendy; Geddes, Donna

2017-02-01

The bacterial content of donated human milk is either endogenous or introduced via contamination. Defining milk bank bacterial content will allow researchers to devise appropriate tests for significant and commonly encountered organisms. A retrospective audit was conducted on data recorded from the Perron Rotary Express Milk Bank, King Edward Memorial Hospital, Subiaco, Western Australia. This aimed to describe the incidence of bacterial species detected in donated human milk and to identify potentially pathogenic bacteria. The data comprised of 2890 batches donated by 448 women between 2007 and 2011. Coagulase negative Staphylococcus (CoNS) represented the highest prevalence of bacteria in donated milk, isolated from 85.5% of batches (range: 20 to 650,000CFU/mL) followed by Acinetobacter species in 8.1% of batches (range: 100 to 180,000CFU/mL). Staphylococcus aureus was the most prevalent potentially pathogenic bacteria in 5% of batches (range: 40 to 100,000CFU/mL). Further investigation is warranted to better define the risks posed by the presence of toxin-producing S. aureus in raw and pasteurized human milk which may allow minimization of risk to the preterm infants. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Growth promotion of the opportunistic human pathogen, Staphylococcus lugdunensis, by heme, hemoglobin, and coculture with Staphylococcus aureus

PubMed Central

Brozyna, Jeremy R; Sheldon, Jessica R; Heinrichs, David E

2014-01-01

Staphylococcus lugdunensis is both a commensal of humans and an opportunistic pathogen. Little is currently known about the molecular mechanisms underpinning the virulence of this bacterium. Here, we demonstrate that in contrast to S. aureus,S. lugdunensis makes neither staphyloferrin A (SA) nor staphyloferrin B (SB) in response to iron deprivation, owing to the absence of the SB gene cluster, and a large deletion in the SA biosynthetic gene cluster. As a result, the species grows poorly in serum-containing media, and this defect was complemented by introduction of the S. aureusSA gene cluster into S. lugdunensis. S. lugdunensis expresses the HtsABC and SirABC transporters for SA and SB, respectively; the latter gene set is found within the isd (heme acquisition) gene cluster. An isd deletion strain was significantly debilitated for iron acquisition from both heme and hemoglobin, and was also incapable of utilizing ferric-SB as an iron source, while an hts mutant could not grow on ferric-SA as an iron source. In iron-restricted coculture experiments, S. aureus significantly enhanced the growth of S. lugdunensis, in a manner dependent on staphyloferrin production by S. aureus, and the expression of the cognate transporters by S. lugdunensis. PMID:24515974

Pathogens Present in Acute Mangled Extremities From Afghanistan and Subsequent Pathogen Recovery

DTIC Science & Technology

2015-01-01

methicillin - resistant Staphylococcus aureus or vancomycin- resistant Enterococcus. Most wounds were colonized with low-virulence...there were no methicillin - resistant Staphylococcus aureus or vancomycin- resistant Enterococcus. Although Enterococcus was recovered at Role 3 and 4 in 9...available for furthermicrobiological analysis in this study.MDRwas defined asmethicillin- resistant Staphylococcus aureus , vancomycin- resistant

PCR-based Approaches for the Detection of Clinical Methicillin-resistant Staphylococcus aureus

PubMed Central

Liu, Ying; Zhang, Jiang; Ji, Yinduo

2016-01-01

Staphylococcus aureus is an important pathogen that can cause a variety of infections, including superficial and systematic infections, in humans and animals. The persistent emergence of multidrug resistant S. aureus, particularly methicillin-resistant S. aureus, has caused dramatically economic burden and concerns in the public health due to limited options of treatment of MRSA infections. In order to make a correct choice of treatment for physicians and understand the prevalence of MRSA, it is extremely critical to precisely and timely diagnose the pathogen that induces a specific infection of patients and to reveal the antibiotic resistant profile of the pathogen. In this review, we outlined different PCR-based approaches that have been successfully utilized for the rapid detection of S. aureus, including MRSA and MSSA, directly from various clinical specimens. The sensitivity and specificity of detections were pointed out. Both advantages and disadvantages of listed approaches were discussed. Importantly, an alternative approach is necessary to further confirm the detection results from the molecular diagnostic assays. PMID:27335617

Fibrinogen Is at the Interface of Host Defense and Pathogen Virulence in Staphylococcus aureus Infection

PubMed Central

Ko, Ya-Ping; Flick, Matthew J.

2017-01-01

Fibrinogen not only plays a pivotal role in hemostasis but also serves key roles in antimicrobial host defense. As a rapidly assembled provisional matrix protein, fibrin(ogen) can function as an early line of host protection by limiting bacterial growth, suppressing dissemination of microbes to distant sites, and mediating host bacterial killing. Fibrinogen-mediated host antimicrobial activity occurs predominantly through two general mechanisms, namely, fibrin matrices functioning as a protective barrier and fibrin(ogen) directly or indirectly driving host protective immune function. The potential of fibrin to limit bacterial infection and disease has been countered by numerous bacterial species evolving and maintaining virulence factors that engage hemostatic system components within vertebrate hosts. Bacterial factors have been isolated that simply bind fibrinogen or fibrin, promote fibrin polymer formation, or promote fibrin dissolution. Staphylococcus aureus is an opportunistic gram-positive bacterium, the causative agent of a wide range of human infectious diseases, and a prime example of a pathogen exquisitely sensitive to host fibrinogen. Indeed, current data suggest fibrinogen serves as a context-dependent determinant of host defense or pathogen virulence in Staphylococcus infection whose ultimate contribution is dictated by the expression of S. aureus virulence factors, the path of infection, and the tissue microenvironment. PMID:27056151

Methicillin-resistant Staphylococcus aureus: a controversial food-borne pathogen.

PubMed

Sergelidis, D; Angelidis, A S

2017-06-01

Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of severe healthcare-associated (HA) infections. Although during the last decade the incidence of HA invasive infections has dropped, the incidence of community-associated MRSA (CA-MRSA) infections has risen among the general population. Moreover, CA-MRSA, livestock-associated MRSA (LA-MRSA) and HA-MRSA (HA-MRSA) can be found in foods intended for human consumption. Several studies from different geographical areas have reported the presence of enterotoxin genes in several MRSA food isolates. Molecular typing studies have revealed genetic relatedness of these enterotoxigenic isolates with isolates incriminated in human infections. The contamination sources for foods, especially animal-origin foods, may be livestock as well as humans involved in animal husbandry and food-processing. Under favourable environmental conditions for growth and enterotoxin production, enterotoxigenic S. aureus isolates present in foods can cause staphylococcal food poisoning (SFP), irrespective of the contamination origin. Owing to the typically moderate clinical manifestations of SFP, the S. aureus strains responsible for SFP (cases or outbreaks) are frequently either not identified or not further characterized. Antimicrobial susceptibility testing is rarely performed, because administration of antimicrobial therapy is not required in the vast majority of cases. Staphylococcal food poisoning is the result of consumption of foods with preformed enterotoxins. Hence, similar to methicillin-sensitive enterotoxigenic S. aureus, enterotoxigenic MRSA can also act as food-borne pathogens upon favourable conditions for growth and enterotoxin production. The severity of the intoxication is not related to the antimicrobial resistance profile of the causative S. aureus strain and therefore MRSA food-borne outbreaks are not expected to be more severe. This review evaluates the potential of methicillin-resistant Staphylococcus aureus (MRSA) as food-borne pathogens based on the current knowledge about the epidemiology of MRSA, their prevalence in livestock, foods of animal origin and humans, and their ability to produce enterotoxins. © 2017 The Society for Applied Microbiology.

An In vitro Model for Bacterial Growth on Human Stratum Corneum.

PubMed

van der Krieken, Danique A; Ederveen, Thomas H A; van Hijum, Sacha A F T; Jansen, Patrick A M; Melchers, Willem J G; Scheepers, Paul T J; Schalkwijk, Joost; Zeeuwen, Patrick L J M

2016-11-02

The diversity and dynamics of the skin microbiome in health and disease have been studied recently, but adequate model systems to study skin microbiotas in vitro are largely lacking. We developed an in vitro system that mimics human stratum corneum, using human callus as substrate and nutrient source for bacterial growth. The growth of several commensal and pathogenic bacterial strains was measured for up to one week by counting colony-forming units or by quantitative PCR with strain-specific primers. Human skin pathogens were found to survive amidst a minimal microbiome consisting of 2 major skin commensals: Staphylococcus epidermidis and Propionibacterium acnes. In addition, complete microbiomes, taken from the backs of healthy volunteers, were inoculated and maintained using this system. This model may enable the modulation of skin microbiomes in vitro and allow testing of pathogens, biological agents and antibiotics in a medium-throughput format.

[Evaluation of the bacteriologic quality of breast milk in a neonatology service in Belgium].

PubMed

Vervoort, A; Delsat, L; Pieltain, C; De Halleux, V; Carpentier, M; Rigo, J

2007-03-01

Many studies demonstrated that human milk is the recommended source of enteral nutrition in preterm infants providing several benefits with regards to feeding tolerance, immunity and cognitive development However, neurological immaturity and associated clinical conditions prevent them from suckling effectively. Therefore, mother's milk must be expressed, stored and transported to the neonatal unit and could be contaminated. The microbiological quality of human milk was evaluated on each donation to the neonatal intensive care unit of the University of Liege, Belgium from November 1, 2003 to January 31, 2005. In all, 5842 samples from 176 mothers were included in the study. Samples were classified according to the exclusive presence of coagulase negative Staphylococcus and their number (less or more than 104 germs per ml) or to contamination with pathogens. More than 50% of analyzed milks had to be pasteurized (46%; >104 coagulase negative Staphylococcus per ml) or to be discarded (7% pathogen contamination). The incidence of pasteurisation tends to increase during the summer, suggesting a seasonal influence. Maternal profiles were established longitudinally. Among the 60 mothers whose at least one sample had pathogen contamination, 27% had a contamination occurring only during a few days, but 73% had more than 50% of their samples discarded. This study suggest the need to promote the use and the financial support of intrahospital human milk bank units to support the safe use of raw and pasteurised human milk in preterm infants.

Antibody-Based Agents in the Management of Antibiotic-Resistant Staphylococcus aureus Diseases

PubMed Central

Speziale, Pietro; Rindi, Simonetta

2018-01-01

Staphylococcus aureus is a human pathogen that can cause a wide spectrum of diseases, including sepsis, pneumonia, arthritis, and endocarditis. Ineffective treatment of a number of staphylococcal infections with antibiotics is due to the development and spread of antibiotic-resistant strains following decades of antibiotic usage. This has generated renewed interest within the scientific community in alternative therapeutic agents, such as anti-S. aureus antibodies. Although the role of antibodies in the management of S. aureus diseases is controversial, the success of this pathogen in neutralizing humoral immunity clearly indicates that antibodies offer the host extensive protection. In this review, we report an update on efforts to develop antibody-based agents, particularly monoclonal antibodies, and their therapeutic potential in the passive immunization approach to the treatment and prevention of S. aureus infections. PMID:29533985

Livestock Origin for a Human Pandemic Clone of Community-Associated Methicillin-Resistant Staphylococcus aureus

PubMed Central

Spoor, Laura E.; McAdam, Paul R.; Weinert, Lucy A.; Rambaut, Andrew; Hasman, Henrik; Aarestrup, Frank M.; Kearns, Angela M.; Larsen, Anders R.; Skov, Robert L.; Fitzgerald, J. Ross

2013-01-01

ABSTRACT The importance of livestock as a source of bacterial pathogens with the potential for epidemic spread in human populations is unclear. In recent years, there has been a global increase in community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections of healthy humans, but an understanding of the different evolutionary origins of CA-MRSA clones and the basis for their recent expansion is lacking. Here, using a high-resolution phylogenetic approach, we report the discovery of two emergent clones of human epidemic CA-MRSA which resulted from independent livestock-to-human host jumps by the major bovine S. aureus complex, CC97. Of note, one of the new clones was isolated from human infections on four continents, demonstrating its global dissemination since the host jump occurred over 40 years ago. The emergence of both human S. aureus clones coincided with the independent acquisition of mobile genetic elements encoding antimicrobial resistance and human-specific mediators of immune evasion, consistent with an important role for these genetic events in the capacity to survive and transmit among human populations. In conclusion, we provide evidence that livestock represent a reservoir for the emergence of new human-pathogenic S. aureus clones with the capacity for pandemic spread. These findings have major public health implications highlighting the importance of surveillance for early identification of emergent clones and improved transmission control measures at the human-livestock interface. PMID:23943757

Targeting agr- and agr-Like Quorum Sensing Systems for Development of Common Therapeutics to Treat Multiple Gram-Positive Bacterial Infections

PubMed Central

Gray, Brian; Hall, Pamela; Gresham, Hattie

2013-01-01

Invasive infection by the Gram-positive pathogen Staphylococcus aureus is controlled by a four gene operon, agr that encodes a quorum sensing system for the regulation of virulence. While agr has been well studied in S. aureus, the contribution of agr homologues and analogues in other Gram-positive pathogens is just beginning to be understood. Intriguingly, other significant human pathogens, including Clostridium perfringens, Listeria monocytogenes, and Enterococcus faecalis contain agr or analogues linked to virulence. Moreover, other significant human Gram-positive pathogens use peptide based quorum sensing systems to establish or maintain infection. The potential for commonality in aspects of these signaling systems across different species raises the prospect of identifying therapeutics that could target multiple pathogens. Here, we review the status of research into these agr homologues, analogues, and other peptide based quorum sensing systems in Gram-positive pathogens as well as the potential for identifying common pathways and signaling mechanisms for therapeutic discovery. PMID:23598501

Gorilla gorilla gorilla gut: a potential reservoir of pathogenic bacteria as revealed using culturomics and molecular tools.

PubMed

Bittar, Fadi; Keita, Mamadou B; Lagier, Jean-Christophe; Peeters, Martine; Delaporte, Eric; Raoult, Didier

2014-11-24

Wild apes are considered to be the most serious reservoir and source of zoonoses. However, little data are available about the gut microbiota and pathogenic bacteria in gorillas. For this propose, a total of 48 fecal samples obtained from 21 Gorilla gorilla gorilla individuals (as revealed via microsatellite analysis) were screened for human bacterial pathogens using culturomics and molecular techniques. By applying culturomics to one index gorilla and using specific media supplemented by plants, we tested 12,800 colonies and identified 147 different bacterial species, including 5 new species. Many opportunistic pathogens were isolated, including 8 frequently associated with human diseases; Mycobacterium bolletii, Proteus mirabilis, Acinetobacter baumannii, Klebsiella pneumoniae, Serratia marcescens, Escherichia coli, Staphylococcus aureus and Clostridium botulinum. The genus Treponema accounted for 27.4% of the total reads identified at the genus level via 454 pyrosequencing. Using specific real-time PCR on 48 gorilla fecal samples, in addition to classical human pathogens, we also observed the fastidious bacteria Bartonella spp. Borrelia spp., Coxiella burnetii and Tropheryma whipplei in the gorilla population. We estimated that the prevalence of these pathogens vary between 4.76% and 85.7%. Therefore, gorillas share many bacterial pathogens with humans suggesting that they could be a reservoir for their emergence.

Gorilla gorilla gorilla gut: a potential reservoir of pathogenic bacteria as revealed using culturomics and molecular tools

PubMed Central

Bittar, Fadi; Keita, Mamadou B.; Lagier, Jean-Christophe; Peeters, Martine; Delaporte, Eric; Raoult, Didier

2014-01-01

Wild apes are considered to be the most serious reservoir and source of zoonoses. However, little data are available about the gut microbiota and pathogenic bacteria in gorillas. For this propose, a total of 48 fecal samples obtained from 21 Gorilla gorilla gorilla individuals (as revealed via microsatellite analysis) were screened for human bacterial pathogens using culturomics and molecular techniques. By applying culturomics to one index gorilla and using specific media supplemented by plants, we tested 12,800 colonies and identified 147 different bacterial species, including 5 new species. Many opportunistic pathogens were isolated, including 8 frequently associated with human diseases; Mycobacterium bolletii, Proteus mirabilis, Acinetobacter baumannii, Klebsiella pneumoniae, Serratia marcescens, Escherichia coli, Staphylococcus aureus and Clostridium botulinum. The genus Treponema accounted for 27.4% of the total reads identified at the genus level via 454 pyrosequencing. Using specific real-time PCR on 48 gorilla fecal samples, in addition to classical human pathogens, we also observed the fastidious bacteria Bartonella spp. Borrelia spp., Coxiella burnetii and Tropheryma whipplei in the gorilla population. We estimated that the prevalence of these pathogens vary between 4.76% and 85.7%. Therefore, gorillas share many bacterial pathogens with humans suggesting that they could be a reservoir for their emergence. PMID:25417711

Antimicrobial and Antibiofilm Activity of Human Milk Oligosaccharides against Streptococcus agalactiae, Staphylococcus aureus, and Acinetobacter baumannii.

PubMed

Ackerman, Dorothy L; Craft, Kelly M; Doster, Ryan S; Weitkamp, Jörn-Hendrik; Aronoff, David M; Gaddy, Jennifer A; Townsend, Steven D

2018-03-09

In a previous study, we reported that human milk oligosaccharides (HMOs) isolated from five donor milk samples possessed antimicrobial and antibiofilm activity against Streptococcus agalactiae, also known as Group B Streptococcus or GBS. Herein, we present a broader evaluation of the antimicrobial and antibiofilm activity by screening HMOs from 14 new donors against three strains of GBS and two of the ESKAPE pathogens of particular interest to child health, Staphylococcus aureus and Acinetobacter baumannii. Growth and biofilm assays showed that HMOs from these new donors possessed antimicrobial and antibiofilm activity against all three strains of GBS, antibiofilm activity against methicillin-resistant S. aureus strain USA300, and antimicrobial activity against A. baumannii strain ATCC 19606.

Role of commercial probiotic strains against human pathogen adhesion to intestinal mucus.

PubMed

Collado, M C; Meriluoto, J; Salminen, S

2007-10-01

The aims of this study present were to assess and to evaluate in vitro the abilities of commercial probiotic strains derived from fermented milk products and related sources currently marketed in European countries, to inhibit, compete and displace the adhesion of selected potential pathogens to immobilized human mucus. The adhesion was assessed by measuring the radioactivity of bacteria adhered to the human mucus. We tested 12 probiotic strains against eight selected pathogens. All strains tested were able to adhere to mucus. All probiotic strains tested were able to inhibit and displace (P<0.05) the adhesion of Bacteroides, Clostridium, Staphylococcus and Enterobacter. In addition, the abilities to inhibit and to displace adhered pathogens depended on both the probiotic and the pathogen strains tested suggesting that several complementary mechanisms are implied in the processes. Our results indicate the need for a case-by-case assessment in order to select strains with the ability to inhibit or displace a specific pathogen. Probiotics could be useful to correct deviations observed in intestinal microbiota associated with specific diseases and also, to prevent pathogen infections. The competitive exclusion properties of probiotics as well as their ability to displace and inhibit pathogens are the most importance for therapeutic manipulation of the enteric microbiota. The application of such strategies could contribute to expand the beneficial properties on human health against pathogen infection.

Recombination-Mediated Host Adaptation by Avian Staphylococcus aureus

PubMed Central

Murray, Susan; Pascoe, Ben; Méric, Guillaume; Mageiros, Leonardos; Yahara, Koji; Hitchings, Matthew D.; Friedmann, Yasmin; Wilkinson, Thomas S.; Gormley, Fraser J.; Mack, Dietrich; Bray, James E.; Lamble, Sarah; Bowden, Rory; Jolley, Keith A.; Maiden, Martin C.J.; Wendlandt, Sarah; Schwarz, Stefan; Corander, Jukka; Fitzgerald, J. Ross

2017-01-01

Staphylococcus aureus are globally disseminated among farmed chickens causing skeletal muscle infections, dermatitis, and septicaemia. The emergence of poultry-associated lineages has involved zoonotic transmission from humans to chickens but questions remain about the specific adaptations that promote proliferation of chicken pathogens. We characterized genetic variation in a population of genome-sequenced S. aureus isolates of poultry and human origin. Genealogical analysis identified a dominant poultry-associated sequence cluster within the CC5 clonal complex. Poultry and human CC5 isolates were significantly distinct from each other and more recombination events were detected in the poultry isolates. We identified 44 recombination events in 33 genes along the branch extending to the poultry-specific CC5 cluster, and 47 genes were found more often in CC5 poultry isolates compared with those from humans. Many of these gene sequences were common in chicken isolates from other clonal complexes suggesting horizontal gene transfer among poultry associated lineages. Consistent with functional predictions for putative poultry-associated genes, poultry isolates showed enhanced growth at 42 °C and greater erythrocyte lysis on chicken blood agar in comparison with human isolates. By combining phenotype information with evolutionary analyses of staphylococcal genomes, we provide evidence of adaptation, following a human-to-poultry host transition. This has important implications for the emergence and dissemination of new pathogenic clones associated with modern agriculture. PMID:28338786

Antimicrobial activity of an aspartic protease from Salpichroa origanifolia fruits.

PubMed

Díaz, M E; Rocha, G F; Kise, F; Rosso, A M; Guevara, M G; Parisi, M G

2018-05-08

Plant proteases play a fundamental role in several processes like growth, development and in response to biotic and abiotic stress. In particular, aspartic proteases (AP) are expressed in different plant organs and have antimicrobial activity. Previously, we purified an AP from Salpichroa origanifolia fruits called salpichroin. The aim of this work was to determine the cytotoxic activity of this enzyme on selected plant and human pathogens. For this purpose, the growth of the selected pathogens was analysed after exposure to different concentrations of salpichroin. The results showed that the enzyme was capable of inhibiting Fusarium solani and Staphylococcus aureus in a dose-dependent manner. It was determined that 1·2 μmol l -1 of salpichroin was necessary to inhibit 50% of conidial germination, and the minimal bactericidal concentration was between 1·9 and 2·5 μmol l -1 . Using SYTOX Green dye we were able to demonstrate that salpichroin cause membrane permeabilization. Moreover, the enzyme treated with its specific inhibitor pepstatin A did not lose its antibacterial activity. This finding demonstrates that the cytotoxic activity of salpichroin is due to the alteration of the cell plasma membrane barrier but not due to its proteolytic activity. Antimicrobial activity of the AP could represent a potential alternative for the control of pathogens that affect humans or crops of economic interest. This study provides insights into the antimicrobial activity of an aspartic protease isolated from Salpichroa origanifolia fruits on plant and human pathogens. The proteinase inhibited Fusarium solani and Staphylococcus aureus in a dose-dependent manner due to the alteration of the cell plasma membrane barrier but not due to its proteolytic activity. Antimicrobial activity of salpichroin suggests its potential applications as an important tool for the control of pathogenic micro-organisms affecting humans and crops of economic interest. Therefore, it would represent a new alternative to avoid the problems of environmental pollution and antimicrobial resistance. © 2018 The Society for Applied Microbiology.

Multidrug Efflux Pumps from Enterobacteriaceae, Vibrio cholerae and Staphylococcus aureus Bacterial Food Pathogens

PubMed Central

Andersen, Jody L.; He, Gui-Xin; Kakarla, Prathusha; KC, Ranjana; Kumar, Sanath; Lakra, Wazir Singh; Mukherjee, Mun Mun; Ranaweera, Indrika; Shrestha, Ugina; Tran, Thuy; Varela, Manuel F.

2015-01-01

Foodborne illnesses caused by bacterial microorganisms are common worldwide and constitute a serious public health concern. In particular, microorganisms belonging to the Enterobacteriaceae and Vibrionaceae families of Gram-negative bacteria, and to the Staphylococcus genus of Gram-positive bacteria are important causative agents of food poisoning and infection in the gastrointestinal tract of humans. Recently, variants of these bacteria have developed resistance to medically important chemotherapeutic agents. Multidrug resistant Escherichia coli, Salmonella enterica, Vibrio cholerae, Enterobacter spp., and Staphylococcus aureus are becoming increasingly recalcitrant to clinical treatment in human patients. Of the various bacterial resistance mechanisms against antimicrobial agents, multidrug efflux pumps comprise a major cause of multiple drug resistance. These multidrug efflux pump systems reside in the biological membrane of the bacteria and actively extrude antimicrobial agents from bacterial cells. This review article summarizes the evolution of these bacterial drug efflux pump systems from a molecular biological standpoint and provides a framework for future work aimed at reducing the conditions that foster dissemination of these multidrug resistant causative agents through human populations. PMID:25635914

Multidrug efflux pumps from Enterobacteriaceae, Vibrio cholerae and Staphylococcus aureus bacterial food pathogens.

PubMed

Andersen, Jody L; He, Gui-Xin; Kakarla, Prathusha; K C, Ranjana; Kumar, Sanath; Lakra, Wazir Singh; Mukherjee, Mun Mun; Ranaweera, Indrika; Shrestha, Ugina; Tran, Thuy; Varela, Manuel F

2015-01-28

Foodborne illnesses caused by bacterial microorganisms are common worldwide and constitute a serious public health concern. In particular, microorganisms belonging to the Enterobacteriaceae and Vibrionaceae families of Gram-negative bacteria, and to the Staphylococcus genus of Gram-positive bacteria are important causative agents of food poisoning and infection in the gastrointestinal tract of humans. Recently, variants of these bacteria have developed resistance to medically important chemotherapeutic agents. Multidrug resistant Escherichia coli, Salmonella enterica, Vibrio cholerae, Enterobacter spp., and Staphylococcus aureus are becoming increasingly recalcitrant to clinical treatment in human patients. Of the various bacterial resistance mechanisms against antimicrobial agents, multidrug efflux pumps comprise a major cause of multiple drug resistance. These multidrug efflux pump systems reside in the biological membrane of the bacteria and actively extrude antimicrobial agents from bacterial cells. This review article summarizes the evolution of these bacterial drug efflux pump systems from a molecular biological standpoint and provides a framework for future work aimed at reducing the conditions that foster dissemination of these multidrug resistant causative agents through human populations.

Inactivation of Staphylococcus aureus and native microflora in human milk by high pressure processing

NASA Astrophysics Data System (ADS)

Windyga, Bożena; Rutkowska, Małgorzata; Sokołowska, Barbara; Skąpska, Sylwia; Wesołowska, Aleksandra; Wilińska, Maria; Fonberg-Broczek, Monika; Rzoska, Sylwester J.

2015-04-01

The storage of unpreserved food, including breast milk, is associated with the growth of microorganisms, including pathogenic bacteria. It is therefore necessary to use suitable processes to eliminate pathogenic microorganisms and reduce the total microbial count in order to ensure product safety for consumers. In the present study, samples of milk obtained from volunteers donating to the human milk bank were artificially contaminated with Staphylococcus aureus ATCC 6538. This bacteria was the model microorganism of choice, being relatively resistant to high pressure as well as posing the most serious risk to infant health. The results obtained show that high pressure processing can reduce the count of S. aureus by about 5 log units at 4°C and about 8 log units at 50°C, and totally eliminate Enterobacteriaceae after 5 min of treatment, and result in a total microbial count reduction after 10 min treatment at 500 MPa at 20°C and 50°C. This suggests the possibility of this technology being applied to ensure the adequate safety and quality of human breast milk in human milk banks. This paper was presented at the LIIth European High Pressure Research Group (EHPRG 52) Meeting in Lyon (France), 7-12 September 2014.

Bactericidal activity of the human skin fatty acid cis-6-hexadecanoic acid on Staphylococcus aureus.

PubMed

Cartron, Michaël L; England, Simon R; Chiriac, Alina Iulia; Josten, Michaele; Turner, Robert; Rauter, Yvonne; Hurd, Alexander; Sahl, Hans-Georg; Jones, Simon; Foster, Simon J

2014-07-01

Human skin fatty acids are a potent aspect of our innate defenses, giving surface protection against potentially invasive organisms. They provide an important parameter in determining the ecology of the skin microflora, and alterations can lead to increased colonization by pathogens such as Staphylococcus aureus. Harnessing skin fatty acids may also give a new avenue of exploration in the generation of control measures against drug-resistant organisms. Despite their importance, the mechanism(s) whereby skin fatty acids kill bacteria has remained largely elusive. Here, we describe an analysis of the bactericidal effects of the major human skin fatty acid cis-6-hexadecenoic acid (C6H) on the human commensal and pathogen S. aureus. Several C6H concentration-dependent mechanisms were found. At high concentrations, C6H swiftly kills cells associated with a general loss of membrane integrity. However, C6H still kills at lower concentrations, acting through disruption of the proton motive force, an increase in membrane fluidity, and its effects on electron transfer. The design of analogues with altered bactericidal effects has begun to determine the structural constraints on activity and paves the way for the rational design of new antistaphylococcal agents. Copyright © 2014 Cartron et al.

Following Pathogen Development and Gene Expression in a Food Ecosystem: the Case of a Staphylococcus aureus Isolate in Cheese

PubMed Central

Aigle, Marina; Fleurot, Renaud; Darrigo, Claire; Hennekinne, Jacques-Antoine; Gruss, Alexandra; Borezée-Durant, Elise; Delacroix-Buchet, Agnès

2014-01-01

Human intoxication or infection due to bacterial food contamination constitutes an economic challenge and a public health problem. Information on the in situ distribution and expression of pathogens responsible for this risk is to date lacking, largely because of technical bottlenecks in detecting signals from minority bacterial populations within a complex microbial and physicochemical ecosystem. We simulated the contamination of a real high-risk cheese with a natural food isolate of Staphylococcus aureus, an enterotoxin-producing pathogen responsible for food poisoning. To overcome the problem of a detection limit in a solid matrix, we chose to work with a fluorescent reporter (superfolder green fluorescent protein) that would allow spatiotemporal monitoring of S. aureus populations and targeted gene expression. The combination of complementary techniques revealed that S. aureus localizes preferentially on the cheese surface during ripening. Immunochemistry and confocal laser scanning microscopy enabled us to visualize, in a single image, dairy bacteria and pathogen populations, virulence gene expression, and the toxin produced. This procedure is readily applicable to other genes of interest, other bacteria, and different types of food matrices. PMID:24928871

In silico Analysis of Toxins of Staphylococcus aureus for Validating Putative Drug Targets.

PubMed

Mohana, Ramadevi; Venugopal, Subhashree

2017-01-01

Toxins are one among the numerous virulence factors produced by the bacteria. These are powerful poisonous substances enabling the bacteria to encounter the defense mechanism of human body. The pathogenic system of Staphylococcus aureus is evolved with various exotoxins that cause detrimental effects on human immune system. Four toxins namely enterotoxin A, exfoliative toxin A, TSST-1 and γ-hemolysin were downloaded from Uniprot database and were analyzed to understand the nature of the toxins and for drug target validation. The results inferred that the toxins were found to interact with many protein partners and no homologous sequences for human proteome were found, and based on similarity search in Drugbank, the targets were identified as novel drug targets. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Draft genome sequences of 64 swine associated LA-MRSA ST5 isolates from the USA

USDA-ARS?s Scientific Manuscript database

Methicillin resistant Staphylococcus aureus colonizes humans and other animals such as swine. LA-MRSA sequence type (ST) 5 isolates are a public concern due to their pathogenicity and ability to acquire mobile genetic elements. This report presents draft genome sequences for 64 LA-MRSA ST5 isolates ...

The olive compound 4-hydroxytyrosol inactivates Staphyloccoccus aureus bacteria and Staphylococcal enterotoxin A (SEA)

USDA-ARS?s Scientific Manuscript database

The foodborne pathogen Staphylococcus aureus produces the virulent staphylococcal enterotoxin A (SEA), a single chain protein which 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, ...

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

USDA-ARS?s Scientific Manuscript database

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...

Germline-encoded neutralization of a Staphylococcus aureus virulence factor by the human antibody repertoire.

PubMed

Yeung, Yik Andy; Foletti, Davide; Deng, Xiaodi; Abdiche, Yasmina; Strop, Pavel; Glanville, Jacob; Pitts, Steven; Lindquist, Kevin; Sundar, Purnima D; Sirota, Marina; Hasa-Moreno, Adela; Pham, Amber; Melton Witt, Jody; Ni, Irene; Pons, Jaume; Shelton, David; Rajpal, Arvind; Chaparro-Riggers, Javier

2016-11-18

Staphylococcus aureus is both an important pathogen and a human commensal. To explore this ambivalent relationship between host and microbe, we analysed the memory humoral response against IsdB, a protein involved in iron acquisition, in four healthy donors. Here we show that in all donors a heavily biased use of two immunoglobulin heavy chain germlines generated high affinity (pM) antibodies that neutralize the two IsdB NEAT domains, IGHV4-39 for NEAT1 and IGHV1-69 for NEAT2. In contrast to the typical antibody/antigen interactions, the binding is primarily driven by the germline-encoded hydrophobic CDRH-2 motifs of IGHV1-69 and IGHV4-39, with a binding mechanism nearly identical for each antibody derived from different donors. Our results suggest that IGHV1-69 and IGHV4-39, while part of the adaptive immune system, may have evolved under selection pressure to encode a binding motif innately capable of recognizing and neutralizing a structurally conserved protein domain involved in pathogen iron acquisition.

Transmission of Staphylococcus aureus from Humans to Green Monkeys in The Gambia as Revealed by Whole-Genome Sequencing.

PubMed

Senghore, Madikay; Bayliss, Sion C; Kwambana-Adams, Brenda A; Foster-Nyarko, Ebenezer; Manneh, Jainaba; Dione, Michel; Badji, Henry; Ebruke, Chinelo; Doughty, Emma L; Thorpe, Harry A; Jasinska, Anna J; Schmitt, Christopher A; Cramer, Jennifer D; Turner, Trudy R; Weinstock, George; Freimer, Nelson B; Pallen, Mark J; Feil, Edward J; Antonio, Martin

2016-10-01

Staphylococcus aureus is an important pathogen of humans and animals. We genome sequenced 90 S. aureus isolates from The Gambia: 46 isolates from invasive disease in humans, 13 human carriage isolates, and 31 monkey carriage isolates. We inferred multiple anthroponotic transmissions of S. aureus from humans to green monkeys (Chlorocebus sabaeus) in The Gambia over different time scales. We report a novel monkey-associated clade of S. aureus that emerged from a human-to-monkey switch estimated to have occurred 2,700 years ago. Adaptation of this lineage to the monkey host is accompanied by the loss of phage-carrying genes that are known to play an important role in human colonization. We also report recent anthroponotic transmission of the well-characterized human lineages sequence type 6 (ST6) and ST15 to monkeys, probably because of steadily increasing encroachment of humans into the monkeys' habitat. Although we have found no evidence of transmission of S. aureus from monkeys to humans, as the two species come into ever-closer contact, there might be an increased risk of additional interspecies exchanges of potential pathogens. The population structures of Staphylococcus aureus in humans and monkeys in sub-Saharan Africa have been previously described using multilocus sequence typing (MLST). However, these data lack the power to accurately infer details regarding the origin and maintenance of new adaptive lineages. Here, we describe the use of whole-genome sequencing to detect transmission of S. aureus between humans and nonhuman primates and to document the genetic changes accompanying host adaptation. We note that human-to-monkey switches tend to be more common than the reverse and that a novel monkey-associated clade is likely to have emerged from such a switch approximately 2,700 years ago. Moreover, analysis of the accessory genome provides important clues as to the genetic changes underpinning host adaptation and, in particular, shows that human-to-monkey switches tend to be associated with the loss of genes known to confer adaptation to the human host. Copyright © 2016 Senghore et al.

Staphylococcus aureus Responds to the Central Metabolite Pyruvate To Regulate Virulence.

PubMed

Harper, Lamia; Balasubramanian, Divya; Ohneck, Elizabeth A; Sause, William E; Chapman, Jessica; Mejia-Sosa, Bryan; Lhakhang, Tenzin; Heguy, Adriana; Tsirigos, Aristotelis; Ueberheide, Beatrix; Boyd, Jeffrey M; Lun, Desmond S; Torres, Victor J

2018-01-23

Staphylococcus aureus is a versatile bacterial pathogen that can cause significant disease burden and mortality. Like other pathogens, S. aureus must adapt to its environment to produce virulence factors to survive the immune responses evoked by infection. Despite the importance of environmental signals for S. aureus pathogenicity, only a limited number of these signals have been investigated in detail for their ability to modulate virulence. Here we show that pyruvate, a central metabolite, causes alterations in the overall metabolic flux of S. aureus and enhances its pathogenicity. We demonstrate that pyruvate induces the production of virulence factors such as the pore-forming leucocidins and that this induction results in increased virulence of community-acquired methicillin-resistant S. aureus (CA-MRSA) clone USA300. Specifically, we show that an efficient "pyruvate response" requires the activation of S. aureus master regulators AgrAC and SaeRS as well as the ArlRS two-component system. Altogether, our report further establishes a strong relationship between metabolism and virulence and identifies pyruvate as a novel regulatory signal for the coordination of the S. aureus virulon through intricate regulatory networks. IMPORTANCE Delineation of the influence of host-derived small molecules on the makeup of human pathogens is a growing field in understanding host-pathogen interactions. S. aureus is a prominent pathogen that colonizes up to one-third of the human population and can cause serious infections that result in mortality in ~15% of cases. Here, we show that pyruvate, a key nutrient and central metabolite, causes global changes to the metabolic flux of S. aureus and activates regulatory networks that allow significant increases in the production of leucocidins. These and other virulence factors are critical for S. aureus to infect diverse host niches, initiate infections, and effectively subvert host immune responses. Understanding how environmental signals, particularly ones that are essential to and prominent in the human host, affect virulence will allow us to better understand pathogenicity and consider more-targeted approaches to tackling the current S. aureus epidemic. Copyright © 2018 Harper et al.

Cultivation of Staphylococcus epidermidis in the Human Spaceflight Environment Leads to Alterations in the Frequency and Spectrum of Spontaneous Rifampicin-Resistance Mutations in the rpoB Gene

PubMed Central

Fajardo-Cavazos, Patricia; Nicholson, Wayne L.

2016-01-01

Bacteria of the genus Staphylococcus are persistent inhabitants of human spaceflight habitats and represent potential opportunistic pathogens. The effect of the human spaceflight environment on the growth and the frequency of mutations to antibiotic resistance in the model organism Staphylococcus epidermidis strain ATCC12228 was investigated. Six cultures of the test organism were cultivated in biological research in canisters–Petri dish fixation units for 122 h on orbit in the International Space Station (ISS) as part of the SpaceX-3 resupply mission. Asynchronous ground controls (GCs) consisted of identical sets of cultures cultivated for 122 h in the ISS Environmental Simulator at Kennedy Space Center. S. epidermidis exhibited significantly lower viable counts but significantly higher frequencies of mutation to rifampicin (Rif) resistance in space vs. GC cultures. The spectrum of mutations in the rpoB gene leading to RifR was altered in S. epidermidis isolates cultivated in the ISS compared to GCs. The results suggest that the human spaceflight environment induces unique physiologic stresses on growing bacterial cells leading to changes in mutagenic potential. PMID:27446039

Cultivation of Staphylococcus epidermidis in the Human Spaceflight Environment Leads to Alterations in the Frequency and Spectrum of Spontaneous Rifampicin-Resistance Mutations in the rpoB Gene.

PubMed

Fajardo-Cavazos, Patricia; Nicholson, Wayne L

2016-01-01

Bacteria of the genus Staphylococcus are persistent inhabitants of human spaceflight habitats and represent potential opportunistic pathogens. The effect of the human spaceflight environment on the growth and the frequency of mutations to antibiotic resistance in the model organism Staphylococcus epidermidis strain ATCC12228 was investigated. Six cultures of the test organism were cultivated in biological research in canisters-Petri dish fixation units for 122 h on orbit in the International Space Station (ISS) as part of the SpaceX-3 resupply mission. Asynchronous ground controls (GCs) consisted of identical sets of cultures cultivated for 122 h in the ISS Environmental Simulator at Kennedy Space Center. S. epidermidis exhibited significantly lower viable counts but significantly higher frequencies of mutation to rifampicin (Rif) resistance in space vs. GC cultures. The spectrum of mutations in the rpoB gene leading to Rif(R) was altered in S. epidermidis isolates cultivated in the ISS compared to GCs. The results suggest that the human spaceflight environment induces unique physiologic stresses on growing bacterial cells leading to changes in mutagenic potential.

Staphylococcus aureus toxin gene hitchhikes on a transferable antibiotic resistance element.

PubMed

Otto, Michael

2010-01-01

Virulence and antibiotic resistance of the dangerous human pathogen Staphylococcus aureus are to large extent determined by the acquisition of mobile genetic elements (MGEs). Up to now, these elements were known to comprise either resistance or virulence determinants, but not a mixture of the two. Queck et al. now found a cytolysin gene of the phenol-soluble modulin (PSM) family within SCCmec elements, which contain methicillin resistance genes and are largely responsible for the spread of methicillin-resistant S. aureus (MRSA). The novel gene, called psm-mec, had a significant impact on virulence in MRSA strains that do not produce high levels of genome-encoded PSMs. This first example of a combination of toxin and resistance genes on one staphylococcal MGE shows that such bundling is possible and may lead to an even faster acquisition of toxin and resistance genes by S. aureus and other staphylococcal pathogens.

Antibacterial and Antifungal Activities of Spices

PubMed Central

Liu, Qing; Meng, Xiao; Li, Ya; Zhao, Cai-Ning; Tang, Guo-Yi; Li, Hua-Bin

2017-01-01

Infectious diseases caused by pathogens and food poisoning caused by spoilage microorganisms are threatening human health all over the world. The efficacies of some antimicrobial agents, which are currently used to extend shelf-life and increase the safety of food products in food industry and to inhibit disease-causing microorganisms in medicine, have been weakened by microbial resistance. Therefore, new antimicrobial agents that could overcome this resistance need to be discovered. Many spices—such as clove, oregano, thyme, cinnamon, and cumin—possessed significant antibacterial and antifungal activities against food spoilage bacteria like Bacillus subtilis and Pseudomonas fluorescens, pathogens like Staphylococcus aureus and Vibrio parahaemolyticus, harmful fungi like Aspergillus flavus, even antibiotic resistant microorganisms such as methicillin resistant Staphylococcus aureus. Therefore, spices have a great potential to be developed as new and safe antimicrobial agents. This review summarizes scientific studies on the antibacterial and antifungal activities of several spices and their derivatives. PMID:28621716

Antibacterial and Antifungal Activities of Spices.

PubMed

Liu, Qing; Meng, Xiao; Li, Ya; Zhao, Cai-Ning; Tang, Guo-Yi; Li, Hua-Bin

2017-06-16

Infectious diseases caused by pathogens and food poisoning caused by spoilage microorganisms are threatening human health all over the world. The efficacies of some antimicrobial agents, which are currently used to extend shelf-life and increase the safety of food products in food industry and to inhibit disease-causing microorganisms in medicine, have been weakened by microbial resistance. Therefore, new antimicrobial agents that could overcome this resistance need to be discovered. Many spices-such as clove, oregano, thyme, cinnamon, and cumin-possessed significant antibacterial and antifungal activities against food spoilage bacteria like Bacillus subtilis and Pseudomonas fluorescens , pathogens like Staphylococcus aureus and Vibrio parahaemolyticus, harmful fungi like Aspergillus flavus, even antibiotic resistant microorganisms such as methicillin resistant Staphylococcus aureus. Therefore, spices have a great potential to be developed as new and safe antimicrobial agents. This review summarizes scientific studies on the antibacterial and antifungal activities of several spices and their derivatives.

Staphylococcus aureus Manipulates Innate Immunity through Own and Host-Expressed Proteases.

PubMed

Pietrocola, Giampiero; Nobile, Giulia; Rindi, Simonetta; Speziale, Pietro

2017-01-01

Neutrophils, complement system and skin collectively represent the main elements of the innate immune system, the first line of defense of the host against many common microorganisms. Bacterial pathogens have evolved strategies to counteract all these defense activities. Specifically, Staphylococcus aureus , a major human pathogen, secretes a variety of immune evasion molecules including proteases, which cleave components of the innate immune system or disrupt the integrity of extracellular matrix and intercellular connections of tissues. Additionally, S. aureus secretes proteins that can activate host zymogens which, in turn, target specific defense components. Secreted proteins can also inhibit the anti-bacterial function of neutrophils or complement system proteases, potentiating S. aureus chances of survival. Here, we review the current understanding of these proteases and modulators of host proteases in the functioning of innate immunity and describe the importance of these mechanisms in the pathology of staphylococcal diseases.

Staphylococcus aureus Manipulates Innate Immunity through Own and Host-Expressed Proteases

PubMed Central

Pietrocola, Giampiero; Nobile, Giulia; Rindi, Simonetta; Speziale, Pietro

2017-01-01

Neutrophils, complement system and skin collectively represent the main elements of the innate immune system, the first line of defense of the host against many common microorganisms. Bacterial pathogens have evolved strategies to counteract all these defense activities. Specifically, Staphylococcus aureus, a major human pathogen, secretes a variety of immune evasion molecules including proteases, which cleave components of the innate immune system or disrupt the integrity of extracellular matrix and intercellular connections of tissues. Additionally, S. aureus secretes proteins that can activate host zymogens which, in turn, target specific defense components. Secreted proteins can also inhibit the anti-bacterial function of neutrophils or complement system proteases, potentiating S. aureus chances of survival. Here, we review the current understanding of these proteases and modulators of host proteases in the functioning of innate immunity and describe the importance of these mechanisms in the pathology of staphylococcal diseases. PMID:28529927

Bacteria from Animals as a Pool of Antimicrobial Resistance Genes

PubMed Central

Argudín, Maria Angeles; Deplano, Ariane; Meghraoui, Alaeddine; Dodémont, Magali; Heinrichs, Amelie; Denis, Olivier; Nonhoff, Claire; Roisin, Sandrine

2017-01-01

Antimicrobial agents are used in both veterinary and human medicine. The intensive use of antimicrobials in animals may promote the fixation of antimicrobial resistance genes in bacteria, which may be zoonotic or capable to transfer these genes to human-adapted pathogens or to human gut microbiota via direct contact, food or the environment. This review summarizes the current knowledge of the use of antimicrobial agents in animal health and explores the role of bacteria from animals as a pool of antimicrobial resistance genes for human bacteria. This review focused in relevant examples within the ESC(K)APE (Enterococcus faecium, Staphylococcus aureus, Clostridium difficile (Klebsiella pneumoniae), Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacteriaceae) group of bacterial pathogens that are the leading cause of nosocomial infections throughout the world. PMID:28587316

Antimicrobial activity of extracts from macroalgae Ulva lactuca against clinically important Staphylococci is impacted by lunar phase of macroalgae harvest.

PubMed

Deveau, A M; Miller-Hope, Z; Lloyd, E; Williams, B S; Bolduc, C; Meader, J M; Weiss, F; Burkholder, K M

2016-05-01

Staphylococcus aureus is a common human bacterial pathogen that causes skin and soft tissue infections. Methicillin-resistant Staph. aureus (MRSA) are increasingly drug-resistant, and thus there is great need for new therapeutics to treat Staph. aureus infections. Attention has focused on potential utility of natural products, such as extracts of marine macroalgae, as a source of novel antimicrobial compounds. The green macroalgae Ulva lactuca produces compounds inhibitory to human pathogens, although the effectiveness of U. lactuca extracts against clinically relevant strains of Staph. aureus is poorly understood. In addition, macroalgae produce secondary metabolites that may be influenced by exogenous factors including lunar phase, but whether lunar phase affects U. lactuca antimicrobial capacity is unknown. We sought to evaluate the antibacterial properties of U. lactuca extracts against medically important Staphylococci, and to determine the effect of lunar phase on antimicrobial activity. We report that U. lactuca methanolic extracts inhibit a range of Staphylococci, and that lunar phase of macrolagae harvest significantly impacts antimicrobial activity, suggesting that antimicrobial properties can be maximized by manipulating time of algal harvest. These findings provide useful parameters for future studies aimed at isolating and characterizing U. lactuca anti-Staphylococcal agents. The growing prevalence of antibiotic-resistant human pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) has intensified efforts towards discovery and development of novel therapeutics. Marine macroalgae like Ulva lactuca are increasingly recognized as potential sources of antimicrobials, but the efficacy of U. lactuca extracts against common, virulent strains of Staph. aureus is poorly understood. We demonstrate that U. lactuca methanolic extracts inhibit a variety of clinically relevant Staphylococcus strains, and that the antimicrobial activity can be maximized by optimizing time of algal harvest. These findings provide potentially useful parameters for future work of isolating and identifying novel antimicrobial agents from macroalgae. © 2016 The Society for Applied Microbiology.

Virulence Factor Targeting of the Bacterial Pathogen Staphylococcus aureus for Vaccine and Therapeutics

PubMed Central

Kane, Trevor L.; Carothers, Katelyn E.; Lee, Shaun W.

2018-01-01

Background Staphylococcus aureus is a major bacterial pathogen capable of causing a range of infections in humans from gastrointestinal disease, skin and soft tissue infections, to severe outcomes such as sepsis. Staphylococcal infections in humans can be frequent and recurring, with treatments becoming less effective due to the growing persistence of antibiotic resistant S. aureus strains. Due to the prevalence of antibiotic resistance, and the current limitations on antibiotic development, an active and highly promising avenue of research has been to develop strategies to specifically inhibit the activity of virulence factors produced S. aureus as an alternative means to treat disease. Objective In this review we specifically highlight several major virulence factors produced by S. aureus for which recent advances in antivirulence approaches may hold promise as an alternative means to treating diseases caused by this pathogen. Strategies to inhibit virulence factors can range from small molecule inhibitors, to antibodies, to mutant and toxoid forms of the virulence proteins. Conclusion The major prevalence of antibiotic resistant strains of S. aureus combined with the lack of new antibiotic discoveries highlight the need for vigorous research into alternative strategies to combat diseases caused by this highly successful pathogen. Current efforts to develop specific antivirulence strategies, vaccine approaches, and alternative therapies for treating severe disease caused by S. aureus have the potential to stem the tide against the limitations that we face in the post-antibiotic era. PMID:27894236

Bacteriocin production of Lactobacillus sp. from intestines of ducks (Anas domesticus L.) incubated at room temperature and antibacterial effectivity against pathogen

NASA Astrophysics Data System (ADS)

Arfani, Nurfitri; Nur, Fatmawati; Hafsan, Azrianingsih, Rodiyati

2017-05-01

Bacteriocin is a peptide that is easily degraded by proteolytic enzymes in the digestive systems of animals, including humans. It has antimicrobial activity against pathogenic bacteria. Lactobacillus sp. is one type of lactic acid bacteria (LAB) that occupies the intestines of ducks (Anas domesticus L.). The purpose of this research was to determine the optimum time of the highest protein production by Lactobacillus sp. and to determine inhibitory activity of bacteriocin against pathogenic bacteria (Escherichia coli and Staphylococcus aureus). Using the Bradford method, the results showed that the optimum time of highest bacteriocin production was after 36 hours of incubation, with a protein content of 0.93 mg/ml. The bacteriocin inhibitory activity against Escherichia coli showed that a protein concentration of 30% gave a maximum inhibition index of 1.1 mm, while for Staphylococcus aureus, a concentration of 70% gave a maximum inhibition index of 0.3 mm. Further research is required to determine the stationary state of bacteriocin production in this circumstance.

Synergistic Photothermal and Antibiotic Killing of Biofilm-Associated Staphylococcus aureus Using Targeted Antibiotic-Loaded Gold Nanoconstructs.

PubMed

Meeker, Daniel G; Jenkins, Samir V; Miller, Emily K; Beenken, Karen E; Loughran, Allister J; Powless, Amy; Muldoon, Timothy J; Galanzha, Ekaterina I; Zharov, Vladimir P; Smeltzer, Mark S; Chen, Jingyi

2016-04-08

Resistance to conventional antibiotics is a growing public health concern that is quickly outpacing the development of new antibiotics. This has led the Infectious Diseases Society of America (IDSA) to designate Enterococcus faecium , Staphylococcus aureus , Klebsiella pneumoniae , Acinetobacter baumannii , Pseudomonas aeruginosa , and Enterobacter species as "ESKAPE pathogens" on the basis of the rapidly decreasing availability of useful antibiotics. This emphasizes the urgent need for alternative therapeutic strategies to combat infections caused by these and other bacterial pathogens. In this study, we used Staphylococcus aureus ( S. aureus ) as a proof-of-principle ESKAPE pathogen to demonstrate that an appropriate antibiotic (daptomycin) can be incorporated into polydopamine-coated gold nanocages (AuNC@PDA) and that daptomycin-loaded AuNC@PDA can be conjugated to antibodies targeting a species-specific surface protein (staphylococcal protein A; Spa) as a means of achieving selective delivery of the nanoconstructs directly to the bacterial cell surface. Targeting specificity was confirmed by demonstrating a lack of binding to mammalian cells, reduced photothermal and antibiotic killing of the Spa-negative species Staphylococcus epidermidis , and reduced killing of S. aureus in the presence of unconjugated anti-Spa antibodies. We demonstrate that laser irradiation at levels within the current safety standard for use in humans can be used to achieve both a lethal photothermal effect and controlled release of the antibiotic, thus resulting in a degree of therapeutic synergy capable of eradicating viable S. aureus cells. The system was validated using planktonic bacterial cultures of both methicillin-sensitive and methicillin-resistant S. aureus strains and subsequently shown to be effective in the context of an established biofilm, thus indicating that this approach could be used to facilitate the effective treatment of intrinsically resistant biofilm infections.

Staphylococcus lugdunensis, a serious pathogen in periprosthetic joint infections: comparison to Staphylococcus aureus and Staphylococcus epidermidis.

PubMed

Lourtet-Hascoët, J; Bicart-See, A; Félicé, M P; Giordano, G; Bonnet, E

2016-10-01

The aim of this study was to assess the characteristics of periprosthetic joint infection (PJI) due to Staphylococcus lugdunensis and to compare these to the characteristics of PJI due to Staphylococcus aureus and Staphylococcus epidermidis. A retrospective multicentre study including all consecutive cases of S. lugdunensis PJI (2000-2014) was performed. Eighty-eight cases of staphylococcal PJI were recorded: 28 due to S. lugdunensis, 30 to S. aureus, and 30 to S. epidermidis, as identified by Vitek 2 or API Staph (bioMérieux). Clinical symptoms were more often reported in the S. lugdunensis group, and the median delay between surgery and infection was shorter for the S. lugdunensis group than for the S. aureus and S. epidermidis groups. Regarding antibiotic susceptibility, the S. lugdunensis strains were susceptible to antibiotics and 61% of the patients could be treated with levofloxacin + rifampicin. The outcome of the PJI was favourable for 89% of patients with S. lugdunensis, 83% with S. aureus, and 97% with S. epidermidis. S. lugdunensis is an emerging pathogen with a pathogenicity quite similar to that of S. aureus. This coagulase-negative Staphylococcus must be identified precisely in PJI, in order to select the appropriate surgical treatment and antibiotics . Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Biochemical and Molecular Analysis of Staphylococcus aureus Clinical Isolates from Hospitalized Patients.

PubMed

Karmakar, Amit; Dua, Parimal; Ghosh, Chandradipa

2016-01-01

Staphylococcus aureus is opportunistic human as well as animal pathogen that causes a variety of diseases. A total of 100 Staphylococcus aureus isolates were obtained from clinical samples derived from hospitalized patients. The presumptive Staphylococcus aureus clinical isolates were identified phenotypically by different biochemical tests. Molecular identification was done by PCR using species specific 16S rRNA primer pairs and finally 100 isolates were found to be positive as Staphylococcus aureus. Screened isolates were further analyzed by several microbiological diagnostics tests including gelatin hydrolysis, protease, and lipase tests. It was found that 78%, 81%, and 51% isolates were positive for gelatin hydrolysis, protease, and lipase activities, respectively. Antibiogram analysis of isolated Staphylococcus aureus strains with respect to different antimicrobial agents revealed resistance pattern ranging from 57 to 96%. Our study also shows 70% strains to be MRSA, 54.3% as VRSA, and 54.3% as both MRSA and VRSA. All the identified isolates were subjected to detection of mecA, nuc, and hlb genes and 70%, 84%, and 40% were found to harbour mecA, nuc, and hlb genes, respectively. The current investigation is highly important and informative for the high level multidrug resistant Staphylococcus aureus infections inclusive also of methicillin and vancomycin.

Occurrence of virulence-associated genes among Staphylococcus saprophyticus isolated from different sources.

PubMed

de Paiva-Santos, Weslley; de Sousa, Viviane Santos; Giambiagi-deMarval, Marcia

2018-03-28

Staphylococcus saprophyticus is an important pathogen responsible for community urinary tract infections (UTI). Besides composing the human microbiota, this species is widely distributed in the environment and the origins of this organism for human infection is not fully characterized. Although some virulence determinants are known, such as d-serine deaminase (DsdA), urease and cell-wall associated proteins, few studies investigated the distribution of virulence-associated genes and analyzed the pathogenic potential of S. saprophyticus strains from different sources. The aim of the present study was to detect the presence of S. saprophyticus genes encoding surface proteins UafA, Aas, Ssp, SdrI, SssF as well as the DsdA and urease enzymes. A total of 142 S. saprophyticus strains were obtained from four sources: UTI, colonization, water and food. It was found, in every tested strain, the presence of genes encoding the surface proteins UafA, Aas, Ssp and SssF and the DsdA and urease enzymes. In contrast, the gene encoding SdrI surface protein was not detected in any of the strains of S. saprophyticus. These results provide a better understanding of the characteristics of S. saprophyticus strains and suggest that isolates from non-human sources have a potential to colonize the urinary tract. Copyright © 2018 Elsevier Ltd. All rights reserved.

The multifaceted resources and microevolution of the successful human and animal pathogen methicillin-resistant Staphylococcus aureus

PubMed Central

Figueiredo, Agnes Marie Sá; Ferreira, Fabienne Antunes

2014-01-01

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most important bacterial pathogens based on its incidence and the severity of its associated infections. In addition, severe MRSA infections can occur in hospitalised patients or healthy individuals from the community. Studies have shown the infiltration of MRSA isolates of community origin into hospitals and variants of hospital-associated MRSA have caused infections in the community. These rapid epidemiological changes represent a challenge for the molecular characterisation of such bacteria as a hospital or community-acquired pathogen. To efficiently control the spread of MRSA, it is important to promptly detect the mecA gene, which is the determinant of methicillin resistance, using a polymerase chain reaction-based test or other rapidly and accurate methods that detect the mecA product penicillin-binding protein (PBP)2a or PBP2’. The recent emergence of MRSA isolates that harbour a mecA allotype, i.e., the mecC gene, infecting animals and humans has raised an additional and significant issue regarding MRSA laboratory detection. Antimicrobial drugs for MRSA therapy are becoming depleted and vancomycin is still the main choice in many cases. In this review, we present an overview of MRSA infections in community and healthcare settings with focus on recent changes in the global epidemiology, with special reference to the MRSA picture in Brazil. PMID:24789555

Antimicrobial resistance in human and animal pathogens in Zambia, Democratic Republic of Congo, Mozambique and Tanzania: an urgent need of a sustainable surveillance system.

PubMed

Mshana, Stephen E; Matee, Mecky; Rweyemamu, Mark

2013-10-12

A review of the published and unpublished literature on bacterial resistance in human and animals was performed. Sixty-eight articles/reports from the Democratic Republic of Congo (DRC), Mozambique, Tanzania and Zambia were reviewed. The majority of these articles were from Tanzania. There is an increasing trend in the incidence of antibiotic resistance; of major concern is the increase in multidrug- resistant Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Vibrio cholera, non-typhoid Salmonella and other pathogens responsible for nosocomial infections. The increase in methicillin- resistant Staphylococcus aureus and extended-spectrum beta-lactamase (ESBL) producers in the countries under review confirms the spread of these clones worldwide. Clinical microbiology services in these countries need to be strengthened in order to allow a coordinated surveillance for antimicrobial resistance and provide data for local treatment guidelines and for national policies to control antimicrobial resistance. While the present study does not provide conclusive evidence to associate the increasing trend in antibiotic resistance in humans with the use of antibiotics in animals, either as feed additives or veterinary prescription, we strongly recommend a one-health approach of systematic surveillance across the public and animal health sectors, as well as the adherence to the FAO (Food and Agriculture Organization)-OIE (World Organization of animal Health) -WHO(World Health Organization) recommendations for non-human antimicrobial usage.

Inhibition of growth of highly resistant bacterial and fungal pathogens by a natural product.

PubMed

Hafidh, Rand R; Abdulamir, Ahmed S; Vern, Law Se; Abu Bakar, Fatimah; Abas, Faridah; Jahanshiri, Fatemeh; Sekawi, Zamberi

2011-01-01

The continuous escalation of resistant bacteria against a wide range of antibiotics necessitates discovering novel unconventional sources of antibiotics. B. oleracea L (red cabbage) is health-promoting food with proven anticancer and anti-inflammatory activities. However, it has not been researched adequately for its antimicrobial activity on potential resistant pathogens. The methanol crude extract of B. oleracea L. was investigated for a possible anti-microbial activity. The screening method was conducted using disc diffusion assay against 22 pathogenic bacteria and fungi. It was followed by evaluation of the minimum inhibitory concentration (MIC). Moreover, the antibacterial and the antifungal activities were confirmed using the minimum bactericidal concentration (MBC) and the minimum fungicidal concentration (MFC), respectively. Remarkable, antibacterial activity was evident particularly against highly infectious microorganisms such as Methicillin-resistant Staphylococcus aureus, Escherichia coli O157:H7, Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus, and Salmonella enterica serovar Typhimurium as well as against human fungal pathogens, Trichophyton rubrum and Aspergillus terreus. Red cabbage is a rich source of phenolic compounds, anthocyanins being the most abundant class, which might explain its potent antimicrobial action. This extract is potentially novel for future antimicrobials, inexpensive, and readily available at a large scale for pharmaceutical companies for further investigation and processing.

Inhibition of Growth of Highly Resistant Bacterial and Fungal Pathogens by a Natural Product

PubMed Central

Hafidh, Rand R; Abdulamir, Ahmed S; Vern, Law Se; Abu Bakar, Fatimah; Abas, Faridah; Jahanshiri, Fatemeh; Sekawi, Zamberi

2011-01-01

The continuous escalation of resistant bacteria against a wide range of antibiotics necessitates discovering novel unconventional sources of antibiotics. B. oleracea L (red cabbage) is health-promoting food with proven anticancer and anti-inflammatory activities. However, it has not been researched adequately for its antimicrobial activity on potential resistant pathogens. The methanol crude extract of B. oleracea L. was investigated for a possible anti-microbial activity. The screening method was conducted using disc diffusion assay against 22 pathogenic bacteria and fungi. It was followed by evaluation of the minimum inhibitory concentration (MIC). Moreover, the antibacterial and the antifungal activities were confirmed using the minimum bactericidal concentration (MBC) and the minimum fungicidal concentration (MFC), respectively. Remarkable, antibacterial activity was evident particularly against highly infectious microorganisms such as Methicillin-resistant Staphylococcus aureus, Escherichia coli O157:H7, Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus, and Salmonella enterica serovar Typhimurium as well as against human fungal pathogens, Trichophyton rubrum and Aspergillus terreus. Red cabbage is a rich source of phenolic compounds, anthocyanins being the most abundant class, which might explain its potent antimicrobial action. This extract is potentially novel for future antimicrobials, inexpensive, and readily available at a large scale for pharmaceutical companies for further investigation and processing. PMID:21915230

Run-off studies demonstrate parallel transport behaviour for a marker of poultry fecal contamination and Staphylococcus aureus.

PubMed

Weidhaas, J; Garner, E; Basden, T; Harwood, V J

2014-08-01

To determine whether poultry litter marker gene LA35 is correlated with pathogens and fecal indicator bacteria (FIB) in run-off from poultry litter-amended plots. A rainfall simulator with various vegetative filter strip lengths was employed to evaluate the correlation of a microbial source tracking (MST) marker for poultry feces/litter (the 16S rRNA gene of Brevibacterium sp. LA35 [LA35] measured by quantitative PCR) with pathogens and FIB in run-off. LA35 was correlated with Staphylococcus aureus, Escherichia coli, Enterococcus spp. and Bacteroidales levels. Salmonella was present at low concentration in litter, but became undetectable by qPCR in run-off. Escherichia coli, LA35 and Staph. aureus exhibited mass-based first flush behaviour in the run-off. Correlation of LA35 with FIB and pathogens in run-off from poultry litter-amended fields suggest comparable transport mechanisms and that LA35 is a useful tracer for harmful bacteria in the environment released from poultry litter. To protect human health, an effective marker for poultry fecal contamination should exhibit similar fate and transport characteristics compared to pathogens. This study is among the first to demonstrate such a relationship in run-off for a MST marker. © 2014 The Society for Applied Microbiology.

Apoptosis, Toll-like, RIG-I-like and NOD-like Receptors Are Pathways Jointly Induced by Diverse Respiratory Bacterial and Viral Pathogens

PubMed Central

Martínez, Isidoro; Oliveros, Juan C.; Cuesta, Isabel; de la Barrera, Jorge; Ausina, Vicente; Casals, Cristina; de Lorenzo, Alba; García, Ernesto; García-Fojeda, Belén; Garmendia, Junkal; González-Nicolau, Mar; Lacoma, Alicia; Menéndez, Margarita; Moranta, David; Nieto, Amelia; Ortín, Juan; Pérez-González, Alicia; Prat, Cristina; Ramos-Sevillano, Elisa; Regueiro, Verónica; Rodriguez-Frandsen, Ariel; Solís, Dolores; Yuste, José; Bengoechea, José A.; Melero, José A.

2017-01-01

Lower respiratory tract infections are among the top five leading causes of human death. Fighting these infections is therefore a world health priority. Searching for induced alterations in host gene expression shared by several relevant respiratory pathogens represents an alternative to identify new targets for wide-range host-oriented therapeutics. With this aim, alveolar macrophages were independently infected with three unrelated bacterial (Streptococcus pneumoniae, Klebsiella pneumoniae, and Staphylococcus aureus) and two dissimilar viral (respiratory syncytial virus and influenza A virus) respiratory pathogens, all of them highly relevant for human health. Cells were also activated with bacterial lipopolysaccharide (LPS) as a prototypical pathogen-associated molecular pattern. Patterns of differentially expressed cellular genes shared by the indicated pathogens were searched by microarray analysis. Most of the commonly up-regulated host genes were related to the innate immune response and/or apoptosis, with Toll-like, RIG-I-like and NOD-like receptors among the top 10 signaling pathways with over-expressed genes. These results identify new potential broad-spectrum targets to fight the important human infections caused by the bacteria and viruses studied here. PMID:28298903

Comparative genome-scale modelling of Staphylococcus aureus strains identifies strain-specific metabolic capabilities linked to pathogenicity

PubMed Central

Bosi, Emanuele; Monk, Jonathan M.; Aziz, Ramy K.; Fondi, Marco; Nizet, Victor; Palsson, Bernhard Ø.

2016-01-01

Staphylococcus aureus is a preeminent bacterial pathogen capable of colonizing diverse ecological niches within its human host. We describe here the pangenome of S. aureus based on analysis of genome sequences from 64 strains of S. aureus spanning a range of ecological niches, host types, and antibiotic resistance profiles. Based on this set, S. aureus is expected to have an open pangenome composed of 7,411 genes and a core genome composed of 1,441 genes. Metabolism was highly conserved in this core genome; however, differences were identified in amino acid and nucleotide biosynthesis pathways between the strains. Genome-scale models (GEMs) of metabolism were constructed for the 64 strains of S. aureus. These GEMs enabled a systems approach to characterizing the core metabolic and panmetabolic capabilities of the S. aureus species. All models were predicted to be auxotrophic for the vitamins niacin (vitamin B3) and thiamin (vitamin B1), whereas strain-specific auxotrophies were predicted for riboflavin (vitamin B2), guanosine, leucine, methionine, and cysteine, among others. GEMs were used to systematically analyze growth capabilities in more than 300 different growth-supporting environments. The results identified metabolic capabilities linked to pathogenic traits and virulence acquisitions. Such traits can be used to differentiate strains responsible for mild vs. severe infections and preference for hosts (e.g., animals vs. humans). Genome-scale analysis of multiple strains of a species can thus be used to identify metabolic determinants of virulence and increase our understanding of why certain strains of this deadly pathogen have spread rapidly throughout the world. PMID:27286824

The Spl Serine Proteases Modulate Staphylococcus aureus Protein Production and Virulence in a Rabbit Model of Pneumonia

PubMed Central

Salgado-Pabon, Wilmara; Meyerholz, David K.; White, Mark J.; Schlievert, Patrick M.

2016-01-01

ABSTRACT The Spl proteases are a group of six serine proteases that are encoded on the νSaβ pathogenicity island and are unique to Staphylococcus aureus. Despite their interesting biochemistry, their biological substrates and functions in virulence have been difficult to elucidate. We found that an spl operon mutant of the community-associated methicillin-resistant S. aureus USA300 strain LAC induced localized lung damage in a rabbit model of pneumonia, characterized by bronchopneumonia observed histologically. Disease in the mutant-infected rabbits was restricted in distribution compared to that in wild-type USA300-infected rabbits. We also found that SplA is able to cleave the mucin 16 glycoprotein from the surface of the CalU-3 lung cell line, suggesting a possible mechanism for wild-type USA300 spreading pneumonia to both lungs. Investigation of the secreted and surface proteomes of wild-type USA300 and the spl mutant revealed multiple alterations in metabolic proteins and virulence factors. This study demonstrates that the Spls modulate S. aureus physiology and virulence, identifies a human target of SplA, and suggests potential S. aureus targets of the Spl proteases. IMPORTANCE Staphylococcus aureus is a versatile human pathogen that produces an array of virulence factors, including several proteases. Of these, six proteases called the Spls are the least characterized. Previous evidence suggests that the Spls are expressed during human infection; however, their function is unknown. Our study shows that the Spls are required for S. aureus to cause disseminated lung damage during pneumonia. Further, we present the first example of a human protein cut by an Spl protease. Although the Spls were predicted not to cut staphylococcal proteins, we also show that an spl mutant has altered abundance of both secreted and surface-associated proteins. This work provides novel insight into the function of Spls during infection and their potential ability to degrade both staphylococcal and human proteins. PMID:27747296

In-vitro screening of Malaysian honey from different floral sources for antibacterial activity on human pathogenic bacteria.

PubMed

Ng, Wen-Jie; Ken, Khai-Wei; Kumar, Roshani-Vijaya; Gunasagaran, Hemamalani; Chandramogan, Vanaysha; Lee, Ying-Yee

2014-01-01

Different researches on therapeutic effects of honey have been conducted in different regions; however the study on the potential antibacterial activity of Malaysian honey is still limited. In this study, antibacterial activities of different monofloral honey samples were tested against several common human pathogenic bacteria. The well-diffusion method, minimum inhibitory concentrations (MIC) and minimum bactericidal concentration (MBC) techniques were employed to investigate the putative antibacterial activity of Malaysian monofloral honey from Koompassia excelsa (Becc.) Taub (Tualang), Melaleuca cajuputi Powell (Gelam) and Durio zibethinus Murr. (Durian). Honey samples were tested against Staphylococcus aureus ATCC6518 and ATCC25923, Staphylococcus epidermidis ATCC12228, Enterococcus faecium LMG16192, Enterococcus faecalis LMG16216 and ATCC29212, Escherichia coli ATCC25922, Salmonella enterica serovar Typhimurium ATCC14028 and Klebsiella pneumoniae ATCC13883. Marked variations were observed in the antibacterial activity of these honey samples. Durian honey failed to produce substantial antibacterial activity, whereas Tualang and Gelam honey showed a spectrum of antibacterial activity with their growth inhibitory effects against all of the tested bacterial species including vancomycin-resistant enterococci (VRE). Present findings suggested Gelam honey possesses highest antibacterial effect among the tested Malaysian honey samples.

Characterization of Micrococcus strains isolated from indoor air.

PubMed

Kooken, Jennifer M; Fox, Karen F; Fox, Alvin

2012-02-01

The characterization of microbes, such as opportunists and pathogens (e.g., methicillin resistant Staphylococcus aureus [MRSA]), in indoor air is important for understanding disease transmission from person-to-person. Common genera found in the human skin microbiome include Micrococcus and Staphylococcus, but there only a limited number of tests to differentiate these genera and/or species. Both genera are believed to be released into indoor air from the shedding of human skin and are morphologically difficult to distinguish. In the current work, after the extraction of proteins from micrococci and the separation of these proteins on one dimensional electrophoretic gels, tryptic peptides were analyzed by MALDI TOF MS and the mass profiles compared with those of a reference strain (ATCC 4698). The results confirmed that all strains were consistent in identity with Micrococcus luteus. Copyright © 2011 Elsevier Ltd. All rights reserved.

Characterization of Micrococcus strains isolated from indoor air

PubMed Central

Kooken, Jennifer M.; Fox, Karen F.; Fox, Alvin

2014-01-01

The characterization of microbes, such as of opportunists and pathogens (e.g. methicillin resistant Staphylococcus aureus [MRSA]), in indoor air is important for understanding disease transmission from person-to-person. Common genera found in the human skin microbiome include Micrococcus and Staphylococcus, but there only a limited number of tests to differentiate these genera and/or species. Both genera are believed to be released into indoor air from the shedding of human skin and are morphologically difficult to distinguish. In the current work, after the extraction of proteins from micrococci and the separation of these proteins on one dimensional electrophoretic gels, tryptic peptides were analyzed by MALDI TOF MS and the mass profiles compared with those of a reference strain (ATCC 4698). The results confirmed that all strains were consistent in identity with Micrococcus luteus. PMID:21963944

Metastatic Complications from Staphylococcus intermedius, a Zoonotic Pathogen

PubMed Central

Sree, Aruna; Tirrell, Sandra; Torres, Brenda; Rothman, Alan L.

2012-01-01

Metastatic infection is an infrequent complication of non-Staphylococcus aureus staphylococcal infection. Here we report a case of bloodstream infection due to Staphylococcus intermedius. To our knowledge, ours is the only known case of metastatic infection with S. intermedius. PMID:22170938

Future challenges in the elimination of bacterial meningitis.

PubMed

Bottomley, Matthew J; Serruto, Davide; Sáfadi, Marco Aurélio Palazzi; Klugman, Keith P

2012-05-30

Despite the widespread implementation of several effective vaccines over the past few decades, bacterial meningitis caused by Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis and Group B Streptococcus (GBS) still results in unacceptably high levels of human mortality and morbidity. A residual disease burden due to bacterial meningitis is also apparent due to a number of persistent or emerging pathogens, including Mycobacterium tuberculosis, Escherichia coli, Staphylococcus aureus, Salmonella spp. and Streptococcus suis. Here, we review the current status of bacterial meningitis caused by these pathogens, highlighting how past and present vaccination programs have attempted to counter these pathogens. We discuss how improved pathogen surveillance, implementation of current vaccines, and development of novel vaccines may be expected to further reduce bacterial meningitis and related diseases in the future. Copyright © 2011 Elsevier Ltd. All rights reserved.

Presence of foodborne pathogens, extended-spectrum β-lactamase -producing Enterobacteriaceae, and methicillin-resistant Staphylococcus aureus in slaughtered reindeer in northern Finland and Norway.

PubMed

Laaksonen, Sauli; Oksanen, Antti; Julmi, Jérôme; Zweifel, Claudio; Fredriksson-Ahomaa, Maria; Stephan, Roger

2017-01-03

Various food-producing animals were recognized in recent years as healthy carriers of bacterial pathogens causing human illness. In northern Fennoscandia, the husbandry of semi-domesticated reindeer (Rangifer tarandus tarandus) is a traditional livelihood and meat is the main product. This study determined the presence of selected foodborne pathogens, methicillin-resistant Staphylococcus aureus (MRSA), and extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae in healthy semi-domesticated reindeer at slaughter in northern Finland and Norway. All 470 reindeer fecal samples tested negative for Salmonella spp., whereas L. monocytogenes was detected in 3%, Yersinia spp. in 10%, and Shiga toxins genes (stx1 and/or stx2) in 33% of the samples. Listeria monocytogenes isolates belonged to the serotype 1/2a (14/15) and 4b, Yersinia spp. were identified mainly as Y. kristensenii (30/46) and Y. enterocolitica (8/46), and stx2 predominated among the Shiga toxin genes (stx2 alone or in combination with stx1 was found in 25% of the samples). With regard to the frequency and distribution of stx1/stx2, striking differences were evident among the 10 different areas of origin. Hence, reindeer could constitute a reservoir for Shiga toxin-producing E. coli (STEC), but strain isolation and characterization is required for verification purposes and to assess the potential human pathogenicity of strains. On the other hand, the favorable antibiotic resistance profiles (only 5% of 95 E. coli isolates were resistant to one or more of the tested antibiotics) and the absence of MRSA and ESBL-producing Enterobacteriaceae (when applying selective methods) suggest only a limited risk of transmission to humans. Healthy semi-domesticated reindeer in northern Finland and Norway can be carriers of certain bacterial foodborne pathogens. Strict compliance with good hygiene practices during any step of slaughter (in particular during dehiding and evisceration) is therefore of central importance to avoid carcass contamination and to prevent foodborne pathogens from entering the food chain.

Identification of causative pathogens in mouse eyes with bacterial keratitis by sequence analysis of 16S rDNA libraries

PubMed Central

Song, Hong-Yan; Qiu, Bao-Feng; Liu, Chun; Zhu, Shun-Xing; Wang, Sheng-Cun; Miao, Jin; Jing, Jing; Shao, Yi-Xiang

2014-01-01

The clone library method using PCR amplification of the 16S ribosomal RNA (rRNA) gene was used to identify pathogens from corneal scrapings of C57BL/6-corneal opacity (B6-Co) mice with bacterial keratitis. All 10 samples from the eyes with bacterial keratitis showed positive PCR results. All 10 samples from the normal cornea showed negative PCR results. In all 10 PCR-positive samples, the predominant and second most predominant species accounted for 20.9 to 40.6% and 14.7 to 26.1%, respectively, of each clone library. The predominant species were Staphylococcus lentus, Pseudomonas aeruginosa, and Staphylococcus epidermidis. The microbiota analysis detected a diverse group of microbiota in the eyes of B6-Co mice with bacterial keratitis and showed that the causative pathogens could be determined based on percentages of bacterial species in the clone libraries. The bacterial species detected in this study were mostly in accordance with results of studies on clinical bacterial keratitis in human eyes. Based on the results of our previous studies and this study, the B6-Co mouse should be considered a favorable model for studying bacterial keratitis. PMID:25312507

Neonatal Staphylococcus lugdunensis urinary tract infection.

PubMed

Hayakawa, Itaru; Hataya, Hiroshi; Yamanouchi, Hanako; Sakakibara, Hiroshi; Terakawa, Toshiro

2015-08-01

Staphylococcus lugdunensis is a known pathogen of infective endocarditis, but not of urinary tract infection. We report a previously healthy neonate without congenital anomalies of the kidney and urinary tract who developed urinary tract infection due to Staphylococcus lugdunensis, illustrating that Staphylococcus lugdunensis can cause urinary tract infection even in those with no urinary tract complications. © 2015 Japan Pediatric Society.

Immunopathogenesis of Staphylococcus aureus pulmonary infection

PubMed Central

Parker, Dane; Prince, Alice

2013-01-01

Staphylococcus aureus is a common human pathogen highly evolved as both a component of the commensal flora and as a major cause of invasive infection. Severe respiratory infection due to staphylococci has been increasing due to the prevalence of more virulent USA300 CA-MRSA strains in the general population. The ability of S. aureus to adapt to the milieu of the respiratory tract has facilitated its emergence as a respiratory pathogen. Its metabolic versatility, the ability to scavenge iron, coordinate gene expression, and the horizontal acquisition of useful genetic elements have all contributed to its success as a component of the respiratory flora, in hospitalized patients, as a complication of influenza and in normal hosts. The expression of surface adhesins facilitates its persistence in the airways. In addition, the highly sophisticated interactions of the multiple S. aureus virulence factors, particularly the α-hemolysin and protein A, with diverse immune effectors in the lung such as ADAM10, TNFR1, EGFR, immunoglobulin, and complement all contribute to the pathogenesis of staphylococcal pneumonia. PMID:22037948

Community-associated and healthcare-associated methicillin-resistant Staphylococcus aureus virulence toward Caenorhabditis elegans compared.

PubMed

Day, Shandra R; Moore, Christopher M; Kundzins, John R; Sifri, Costi D

2012-11-15

Community-associated (CA) methicillin-resistant Staphylococcus aureus (MRSA) strains have emerged as major human pathogens. CA-MRSA virulence appears to be distinct from healthcare-associated (HA) MRSA with several factors [α-hemolysin (Hla), Panton-Valentine leukocidin (PVL), α-type phenol soluble modulins (PSMα) and SCCmec IV] postulated to enhance virulence or fitness. Using the Caenorhabditis elegans infection model, we compared the virulence of clinical and laboratory isolates of CA-MRSA and HA-MRSA and explored the contribution of CA-MRSA associated virulence factors to nematode killing. All CA-MRSA strains were highly pathogenic to nematodes, while HA-MRSA strains demonstrated variable nematode killing. Nematode killing by isogenic mutants of hla or the loci for PVL, PSMα, PSMβ, PSMδ or SCCmec IV was not different than the parental strains. These results demonstrate that CA-MRSA is highly virulent, shows some strains of HA-MRSA are equally virulent toward nematodes and suggests CA-MRSA virulence in C. elegans is not linked to a single virulence factor.

Community-associated and healthcare-associated methicillin-resistant Staphylococcus aureus virulence toward Caenorhabditis elegans compared

PubMed Central

Day, Shandra R.; Moore, Christopher M.; Kundzins, John R.; Sifri, Costi D.

2012-01-01

Community-associated (CA) methicillin-resistant Staphylococcus aureus (MRSA) strains have emerged as major human pathogens. CA-MRSA virulence appears to be distinct from healthcare-associated (HA) MRSA with several factors [α-hemolysin (Hla), Panton-Valentine leukocidin (PVL), α-type phenol soluble modulins (PSMα) and SCCmec IV] postulated to enhance virulence or fitness. Using the Caenorhabditis elegans infection model, we compared the virulence of clinical and laboratory isolates of CA-MRSA and HA-MRSA and explored the contribution of CA-MRSA associated virulence factors to nematode killing. All CA-MRSA strains were highly pathogenic to nematodes, while HA-MRSA strains demonstrated variable nematode killing. Nematode killing by isogenic mutants of hla or the loci for PVL, PSMα, PSMβ, PSMδ or SCCmec IV was not different than the parental strains. These results demonstrate that CA-MRSA is highly virulent, shows some strains of HA-MRSA are equally virulent toward nematodes and suggests CA-MRSA virulence in C. elegans is not linked to a single virulence factor. PMID:23076331

Transcriptional specialization of human dendritic cell subsets in response to microbial vaccines

PubMed Central

Banchereau, Romain; Baldwin, Nicole; Cepika, Alma-Martina; Athale, Shruti; Xue, Yaming; Yu, Chun I; Metang, Patrick; Cheruku, Abhilasha; Berthier, Isabelle; Gayet, Ingrid; Wang, Yuanyuan; Ohouo, Marina; Snipes, LuAnn; Xu, Hui; Obermoser, Gerlinde; Blankenship, Derek; Oh, Sangkon; Ramilo, Octavio; Chaussabel, Damien; Banchereau, Jacques; Palucka, Karolina; Pascual, Virginia

2014-01-01

The mechanisms by which microbial vaccines interact with human APCs remain elusive. Herein, we describe the transcriptional programs induced in human DCs by pathogens, innate receptor ligands and vaccines. Exposure of DCs to influenza, Salmonella enterica and Staphylococcus aureus allows us to build a modular framework containing 204 transcript clusters. We use this framework to characterize the responses of human monocytes, monocyte-derived DCs and blood DC subsets to 13 vaccines. Different vaccines induce distinct transcriptional programs based on pathogen type, adjuvant formulation and APC targeted. Fluzone, Pneumovax and Gardasil, respectively, activate monocyte-derived DCs, monocytes and CD1c+ blood DCs, highlighting APC specialization in response to vaccines. Finally, the blood signatures from individuals vaccinated with Fluzone or infected with influenza reveal a signature of adaptive immunity activation following vaccination and symptomatic infections, but not asymptomatic infections. These data, offered with a web interface, may guide the development of improved vaccines. PMID:25335753

Vesicle formation as a result of interaction between polymorphonuclear neutrophils and Staphylococcus aureus biofilm.

PubMed

Chebotar, Igor' V; Konchakova, Evgenia D; Maianskii, Andrey N

2013-08-01

Staphylococcus aureus, a major opportunistic pathogen, is a leading cause of biofilm-related infections in clinical practice. Staphylococcal biofilms are highly resistant to antibacterial medicines and immune effector cells. The main result of our work is the discovery of nano-vesicles in the supernatant of the human neutrophil-S. aureus biofilm system. We also found that phospholipase C treatment causes complete destruction of these vesicles. While the addition of proteinase K led to a partial structural disorganization of the vesicles, DNase treatment did not influence the vesicle structure. These observations allowed us to conclude that phospholipids and proteins play a structure-forming role in the formation of these nano-vesicles. The vesicles demonstrated anti-biofilm activities when tested against Staphylococcus epidermidis (strains 178M and 328/5) biofilms, but were ineffective for S. aureus (strains 5983/2, 5663 and 18A) biofilms.

Detection of hepatitis E virus and other livestock-related pathogens in Iowa streams

USGS Publications Warehouse

Givens, Carrie E.; Kolpin, Dana W.; Borchardt, Mark A.; Duris, Joseph W.; Moorman, Thomas B.; Spencer, Susan K.

2016-01-01

Manure application is a source of pathogens to the environment. Through overland runoff and tile drainage, zoonotic pathogens can contaminate surface water and streambed sediment and could affect both wildlife and human health. This study examined the environmental occurrence of gene markers for livestock-related bacterial, protozoan, and viral pathogens and antibiotic resistance in surface waters within the South Fork Iowa River basin before and after periods of swine manure application on agricultural land. Increased concentrations of indicator bacteria after manure application exceeding Iowa's state bacteria water quality standards suggest that swine manure contributes to diminished water quality and may pose a risk to human health. Additionally, the occurrence of HEV and numerous bacterial pathogen genes for Escherichia coli, Enterococcus spp., Salmonella sp., and Staphylococcus aureus in both manure samples and in corresponding surface water following periods of manure application suggests a potential role for swine in the spreading of zoonotic pathogens to the surrounding environment. During this study, several zoonotic pathogens were detected including Shiga-toxin producing E. coli, Campylobacter jejuni, pathogenic enterococci, and S. aureus; all of which can pose mild to serious health risks to swine, humans, and other wildlife. This research provides the foundational understanding required for future assessment of the risk to environmental health from livestock-related zoonotic pathogen exposures in this region. This information could also be important for maintaining swine herd biosecurity and protecting the health of wildlife near swine facilities.

Staphylococcus aureus, phagocyte NADPH oxidase and chronic granulomatous disease.

PubMed

Buvelot, Helene; Posfay-Barbe, Klara M; Linder, Patrick; Schrenzel, Jacques; Krause, Karl-Heinz

2017-03-01

Dysfunction of phagocytes is a relevant risk factor for staphylococcal infection. The most common hereditary phagocyte dysfunction is chronic granulomatous disease (CGD), characterized by impaired generation of reactive oxygen species (ROS) due to loss of function mutations within the phagocyte NADPH oxidase NOX2. Phagocytes ROS generation is fundamental to eliminate pathogens and to regulate the inflammatory response to infection. CGD is characterized by recurrent and severe bacterial and fungal infections, with Staphylococcus aureus as the most frequent pathogen, and skin and lung abscesses as the most common clinical entities. Staphylococcus aureus infection may occur in virtually any human host, presumably because of the many virulence factors of the bacterium. However, in the presence of functional NOX2, staphylococcal infections remain rare and are mainly linked to breaches of the skin barrier. In contrast, in patients with CGD, S. aureus readily survives and frequently causes clinically apparent disease. Astonishingly, little is known why S. aureus, which possesses a wide range of antioxidant enzymes (e.g. catalase, SOD), is particularly sensitive to control through NOX2. In this review, we will evaluate the discovery of CGD and our present knowledge of the role of NOX2 in S. aureus infection. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Linoleic acid salt with ultrapure soft water as an antibacterial combination against dermato-pathogenic Staphylococcus spp.

PubMed

Jang, H; Makita, Y; Jung, K; Ishizaka, S; Karasawa, K; Oida, K; Takai, M; Matsuda, H; Tanaka, A

2016-02-01

Skin colonization of Staphylococcus spp. critically affects the severity of dermatitis in humans and animals. We examined different types of fatty acid salts for their antibacterial activity against Staphylococcus spp. when used in ultrapure soft water (UPSW). We also evaluated their therapeutic effect on a spontaneous canine model of dermatitis. UPSW, in which Ca(++) and Mg(++) were replaced with Na(+) , was generated using a water softener with cation-exchange resin. Staphylococcus aureus (Staph. aureus), Staphylococcus intermedius (Staph. intermedius), and Staphylococcus pseudintermedius (Staph. pseudintermedius) were incubated with various fatty acid salts in distilled water (DW) or UPSW and the number of bacteria was counted. Among the fatty acids, oleic acid salt and linoleic acid (LA) salt reduced the number of these bacteria. Also, UPSW enhanced the antibacterial effect of LA on Staph. spp. In spontaneously developed itchy dermatitis in companion dogs, shampoo treatment with liquid soap containing 10% LA in UPSW improved skin conditions. LA salt showed antibacterial activity against Staph. spp. Treatment with soap containing LA with UPSW reduced clinical conditions in dogs with dermatitis. Because colonization of Staph. spp. on the skin exacerbates dermatitis, the use of LA-containing soap in UPSW may reduce unpleasant clinical symptoms of the skin. © 2015 The Society for Applied Microbiology.

A Shared Population of Epidemic Methicillin-Resistant Staphylococcus aureus 15 Circulates in Humans and Companion Animals

PubMed Central

Harrison, Ewan M.; Weinert, Lucy A.; Holden, Matthew T. G.; Welch, John J.; Wilson, Katherine; Morgan, Fiona J. E.; Harris, Simon R.; Loeffler, Anette; Boag, Amanda K.; Peacock, Sharon J.; Paterson, Gavin K.; Waller, Andrew S.; Parkhill, Julian

2014-01-01

ABSTRACT Methicillin-resistant Staphylococcus aureus (MRSA) is a global human health problem causing infections in both hospitals and the community. Companion animals, such as cats, dogs, and horses, are also frequently colonized by MRSA and can become infected. We sequenced the genomes of 46 multilocus sequence type (ST) 22 MRSA isolates from cats and dogs in the United Kingdom and compared these to an extensive population framework of human isolates from the same lineage. Phylogenomic analyses showed that all companion animal isolates were interspersed throughout the epidemic MRSA-15 (EMRSA-15) pandemic clade and clustered with human isolates from the United Kingdom, with human isolates basal to those from companion animals, suggesting a human source for isolates infecting companion animals. A number of isolates from the same veterinary hospital clustered together, suggesting that as in human hospitals, EMRSA-15 isolates are readily transmitted in the veterinary hospital setting. Genome-wide association analysis did not identify any host-specific single nucleotide polymorphisms (SNPs) or virulence factors. However, isolates from companion animals were significantly less likely to harbor a plasmid encoding erythromycin resistance. When this plasmid was present in animal-associated isolates, it was more likely to contain mutations mediating resistance to clindamycin. This finding is consistent with the low levels of erythromycin and high levels of clindamycin used in veterinary medicine in the United Kingdom. This study furthers the “one health” view of infectious diseases that the pathogen pool of human and animal populations are intrinsically linked and provides evidence that antibiotic usage in animal medicine is shaping the population of a major human pathogen. PMID:24825010

Gold Nanoparticles: An Efficient Antimicrobial Agent against Enteric Bacterial Human Pathogen

PubMed Central

Shamaila, Shahzadi; Zafar, Noshin; Riaz, Saira; Sharif, Rehana; Nazir, Jawad; Naseem, Shahzad

2016-01-01

Enteric bacterial human pathogens, i.e., Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Klebsiella pneumoniae, are the major cause of diarrheal infections in children and adults. Their structure badly affects the human immune system. It is important to explore new antibacterial agents instead of antibiotics for treatment. This project is an attempt to explain how gold nanoparticles affect these bacteria. We investigated the important role of the mean particle size, and the inhibition of a bacterium is dose-dependent. Ultra Violet (UV)-visible spectroscopy revealed the size of chemically synthesized gold nanoparticle as 6–40 nm. Atomic force microscopy (AFM) analysis confirmed the size and X-ray diffractometry (XRD) analysis determined the polycrystalline nature of gold nanoparticles. The present findings explained how gold nanoparticles lyse Gram-negative and Gram-positive bacteria. PMID:28335198

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

In vitro comparison of nitroethane, 2-nitro-1-propanol, lauric acid, Lauricidin(R), and the Hawaiian marine algae, Chaetoceros, activity against anaerobically grown Staphylococcus aureus

USDA-ARS?s Scientific Manuscript database

The gastrointestinal tract of bovines often contains bacteria that contribute to disorders of the rumen and may also contain foodborne or opportunistic human pathogens as well as causative agents of mastitis in cows. Thus, there is a need to develop broad-spectrum therapies that are effective while...

Identification, typing, ecology and epidemiology of coagulase negative staphylococci associated with ruminants.

PubMed

Vanderhaeghen, Wannes; Piepers, Sofie; Leroy, Frédéric; Van Coillie, Els; Haesebrouck, Freddy; De Vliegher, Sarne

2015-01-01

Since phenotypic methods to identify coagulase negative staphylococci (CNS) from the milk of ruminants often yield unreliable results, methods for molecular identification based on gene sequencing or fingerprinting techniques have been developed. In addition to culture-based detection of isolates, culture-independent methods may be of interest. On the basis of molecular studies, the five CNS species commonly causing intramammary infections (IMI) are Staphylococcus chromogenes, Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus simulans and Staphylococcus xylosus. Current knowledge suggests that S. chromogenes is a bovine-adapted species, with most cases of IMI due to this bacterium being opportunistic. S. haemolyticus also appears to be an opportunistic pathogen, but this bacterium occupies a variety of habitats, the importance of which as a source of IMI remains to be elucidated. S. xylosus appears to be a versatile species, but little is known of its epidemiology. S. epidermidis is considered to be a human-adapted species and most cases of IMI appear to arise from human sources, but the organism is capable of residing in other habitats. S. simulans typically causes contagious IMI, but opportunistic cases also occur and the ecology of this bacterium requires further study. Further studies of the ecology and epidemiology of CNS as a cause of IMI in cattle are required, along with careful attention to classification of these bacteria and the diseases they cause. Copyright © 2014 Elsevier Ltd. All rights reserved.

Staphylococcus chromogenes, a Coagulase-Negative Staphylococcus Species That Can Clot Plasma.

PubMed

Dos Santos, Danielle Cabral; Lange, Carla Christine; Avellar-Costa, Pedro; Dos Santos, Katia Regina Netto; Brito, Maria Aparecida Vasconcelos Paiva; Giambiagi-deMarval, Marcia

2016-05-01

Staphylococcus chromogenes is one of the main coagulase-negative staphylococci isolated from mastitis of dairy cows. We describe S. chromogenes isolates that can clot plasma. Since the main pathogen causing mastitis is coagulase-positive Staphylococcus aureus, the coagulase-positive phenotype of S. chromogenes described here can easily lead to misidentification. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Modeling antibiotic and cytotoxic effects of the dimeric isoquinoline IQ-143 on metabolism and its regulation in Staphylococcus aureus, Staphylococcus epidermidis and human cells

PubMed Central

2011-01-01

Background Xenobiotics represent an environmental stress and as such are a source for antibiotics, including the isoquinoline (IQ) compound IQ-143. Here, we demonstrate the utility of complementary analysis of both host and pathogen datasets in assessing bacterial adaptation to IQ-143, a synthetic analog of the novel type N,C-coupled naphthyl-isoquinoline alkaloid ancisheynine. Results Metabolite measurements, gene expression data and functional assays were combined with metabolic modeling to assess the effects of IQ-143 on Staphylococcus aureus, Staphylococcus epidermidis and human cell lines, as a potential paradigm for novel antibiotics. Genome annotation and PCR validation identified novel enzymes in the primary metabolism of staphylococci. Gene expression response analysis and metabolic modeling demonstrated the adaptation of enzymes to IQ-143, including those not affected by significant gene expression changes. At lower concentrations, IQ-143 was bacteriostatic, and at higher concentrations bactericidal, while the analysis suggested that the mode of action was a direct interference in nucleotide and energy metabolism. Experiments in human cell lines supported the conclusions from pathway modeling and found that IQ-143 had low cytotoxicity. Conclusions The data suggest that IQ-143 is a promising lead compound for antibiotic therapy against staphylococci. The combination of gene expression and metabolite analyses with in silico modeling of metabolite pathways allowed us to study metabolic adaptations in detail and can be used for the evaluation of metabolic effects of other xenobiotics. PMID:21418624

The poultry red mite (Dermanyssus gallinae): a potential vector of pathogenic agents.

PubMed

Valiente Moro, Claire; De Luna, Carlos J; Tod, Alexander; Guy, Jonathan H; Sparagano, Olivier A E; Zenner, Lionel

2009-06-01

The poultry red mite, D. gallinae has been involved in the transmission of many pathogenic agents, responsible for serious diseases both in animals and humans. Nowadays, few effective methods are available to control the ectoparasite in poultry farms. Consequently, this is an emerging problem which must be taken into account to maintain good health in commercial egg production. This paper addresses the vector capacity of the ectoparasite with special emphasis on salmonellae, pathogenic agents responsible for many of the most important outbreaks of food-borne diseases worlwide. It has been experimentally shown that D. gallinae could act as a biological vector of S. enteritidis and natural carriage of these bacteria by the mite on poultry premises has also been reported. It was also found that D. gallinae carried other pathogens such as E. coli, Shigella sp., and Staphylococcus, thus increasing the list of pathogenic agents potentially transmitted by the mite.

Live Attenuated Influenza Vaccine Enhances Colonization of Streptococcus pneumoniae and Staphylococcus aureus in Mice

PubMed Central

Mina, Michael J.; McCullers, Jonathan A.; Klugman, Keith P.

2014-01-01

ABSTRACT Community interactions at mucosal surfaces between viruses, like influenza virus, and respiratory bacterial pathogens are important contributors toward pathogenesis of bacterial disease. What has not been considered is the natural extension of these interactions to live attenuated immunizations, and in particular, live attenuated influenza vaccines (LAIVs). Using a mouse-adapted LAIV against influenza A (H3N2) virus carrying the same mutations as the human FluMist vaccine, we find that LAIV vaccination reverses normal bacterial clearance from the nasopharynx and significantly increases bacterial carriage densities of the clinically important bacterial pathogens Streptococcus pneumoniae (serotypes 19F and 7F) and Staphylococcus aureus (strains Newman and Wright) within the upper respiratory tract of mice. Vaccination with LAIV also resulted in 2- to 5-fold increases in mean durations of bacterial carriage. Furthermore, we show that the increases in carriage density and duration were nearly identical in all aspects to changes in bacterial colonizing dynamics following infection with wild-type (WT) influenza virus. Importantly, LAIV, unlike WT influenza viruses, had no effect on severe bacterial disease or mortality within the lower respiratory tract. Our findings are, to the best of our knowledge, the first to demonstrate that vaccination with a live attenuated viral vaccine can directly modulate colonizing dynamics of important and unrelated human bacterial pathogens, and does so in a manner highly analogous to that seen following wild-type virus infection. PMID:24549845

Characterization of Methicillin Resistant Staphylococcus aureus isolated from human and animal samples in Egypt.

PubMed

Bendary, M M; Solyman, S M; Azab, M M; Mahmoud, N F; Hanora, A M

2016-02-29

Staphylococcus aureus (S. aureus) has been one of the most problematic pathogens. Methicillin Resistant S. aureus (MRSA) has emerged as a major concern for both human and animal. Antibiotic resistance genes dissemination might be possible between human and animal bacteria. The aim of this study is to show phenotypic and genotypic diversity of human and animal MRSA isolates. Antibiogram typing and biofilm production were used as a primary phenotypic typing tool for the characterization of (40) animal and (38) human MRSA isolates. Genetic typing based on sequencing of 16S rRNA gene and virulence gene profiles were done. Antimicrobial resistance profiles of the animal isolates showed little evidence of widespread of resistance, although this was seen in many human isolates. The biofilm production was detected in higher percentage among animal isolates. Based on the genetic typing and multiple antibiotic resistance (MAR) index, the majority of animal isolates clustered into lineages that were not found in human isolates. Animal and human MRSA isolates showed diversity in antibiotic resistance and virulence gene profiles may be due to host adaptation or chances for contamination between the two hosts were not present in our study.

Methicillin-Resistant Staphylococcus aureus Associated with Animals and Its Relevance to Human Health

PubMed Central

Pantosti, Annalisa

2012-01-01

Staphylococcus aureus is a typical human pathogen. Some animal S. aureus lineages have derived from human strains following profound genetic adaptation determining a change in host specificity. Due to the close relationship of animals with the environmental microbiome and resistome, animal staphylococcal strains also represent a source of resistance determinants. Methicillin-resistant S. aureus (MRSA) emerged 50 years ago as a nosocomial pathogen but in the last decade it has also become a frequent cause of infections in the community. The recent finding that MRSA frequently colonizes animals, especially livestock, has been a reason for concern, as it has revealed an expanded reservoir of MRSA. While MRSA strains recovered from companion animals are generally similar to human nosocomial MRSA, MRSA strains recovered from food animals appear to be specific animal-adapted clones. Since 2005, MRSA belonging to ST398 was recognized as a colonizer of pigs and human subjects professionally exposed to pig farming. The “pig” MRSA was also found to colonize other species of farmed animals, including horses, cattle, and poultry and was therefore designated livestock-associated (LA)-MRSA. LA-MRSA ST398 can cause infections in humans in contact with animals, and can infect hospitalized people, although at the moment this occurrence is relatively rare. Other animal-adapted MRSA clones have been detected in livestock, such as ST1 and ST9. Recently, ST130 MRSA isolated from bovine mastitis has been found to carry a novel mecA gene that eludes detection by conventional PCR tests. Similar ST130 strains have been isolated from human infections in UK, Denmark, and Germany at low frequency. It is plausible that the increased attention to animal MRSA will reveal other strains with peculiar characteristics that can pose a risk to human health. PMID:22509176

Antimicrobial resistance of Staphylococcus aureus isolates from dairy cows and genetic diversity of resistant isolates

USDA-ARS?s Scientific Manuscript database

Staphylococcus aureus is a frequent and major contagious mastitis bacterial pathogen. The antibiotic treatment cure rates vary considerably from 4% to 92%. Staphylococcus aureus readily becomes resistant to antibiotics, resulting in persistent noncurable intramammary infection that usually results i...

Genomic epidemiology of methicillin-susceptible Staphylococcus aureus across colonisation and skin and soft tissue infection.

PubMed

Grinberg, Alex; Biggs, Patrick J; Zhang, Ji; Ritchie, Stephen; Oneroa, Zachary; O'Neill, Charlotte; Karkaba, Ali; Velathanthiri, Niluka S; Coombs, Geoffrey W

2017-10-01

Staphylococcus aureus skin and soft tissue infection (Sa-SSTI) places a significant burden on healthcare systems. New Zealand has a high incidence of Sa-SSTI, and here most morbidity is caused by a polyclonal methicillin-susceptible (MSSA) bacterial population. However, MSSA also colonise asymptomatically the cornified epithelia of approximately 20% of the population, and their divide between commensalism and pathogenicity is poorly understood. We aimed to see whether MSSA are genetically differentiated across colonisation and SSTI; and given the close interactions between people and pets, whether strains isolated from pets differ from human strains. We compared the genomes of contemporaneous colonisation and clinical MSSA isolates obtained in New Zealand from humans and pets. Core and accessory genome comparisons revealed a homogeneous bacterial population across colonisation, disease, humans, and pets. The rate of MSSA colonisation in dogs was comparatively low (5.4%). In New Zealand, most Sa-SSTI morbidity is caused by a random sample of the colonising MSSA population, consistent with the opportunistic infection model rather than the paradigm distinguishing strains according to their pathogenicity. Thus, studies of the factors determining colonisation and immune-escape may be more beneficial than comparative virulence studies. Contact with house-hold pets may pose low zoonotic risk. Copyright © 2017 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

Extensive Horizontal Gene Transfer during Staphylococcus aureus Co-colonization In Vivo

PubMed Central

McCarthy, Alex J.; Loeffler, Anette; Witney, Adam A.; Gould, Katherine A.; Lloyd, David H.; Lindsay, Jodi A.

2014-01-01

Staphylococcus aureus is a commensal and major pathogen of humans and animals. Comparative genomics of S. aureus populations suggests that colonization of different host species is associated with carriage of mobile genetic elements (MGE), particularly bacteriophages and plasmids capable of encoding virulence, resistance, and immune evasion pathways. Antimicrobial-resistant S. aureus of livestock are a potential zoonotic threat to human health if they adapt to colonize humans efficiently. We utilized the technique of experimental evolution and co-colonized gnotobiotic piglets with both human- and pig-associated variants of the lineage clonal complex 398, and investigated growth and genetic changes over 16 days using whole genome sequencing. The human isolate survived co-colonization on piglets more efficiently than in vitro. During co-colonization, transfer of MGE from the pig to the human isolate was detected within 4 h. Extensive and repeated transfer of two bacteriophages and three plasmids resulted in colonization with isolates carrying a wide variety of mobilomes. Whole genome sequencing of progeny bacteria revealed no acquisition of core genome polymorphisms, highlighting the importance of MGE. Staphylococcus aureus bacteriophage recombination and integration into novel sites was detected experimentally for the first time. During colonization, clones coexisted and diversified rather than a single variant dominating. Unexpectedly, each piglet carried unique populations of bacterial variants, suggesting limited transmission of bacteria between piglets once colonized. Our data show that horizontal gene transfer occurs at very high frequency in vivo and significantly higher than that detectable in vitro. PMID:25260585

Recombinant Endolysins as Potential Therapeutics against Antibiotic-Resistant Staphylococcus aureus: Current Status of Research and Novel Delivery Strategies.

PubMed

Haddad Kashani, Hamed; Schmelcher, Mathias; Sabzalipoor, Hamed; Seyed Hosseini, Elahe; Moniri, Rezvan

2018-01-01

Staphylococcus aureus is one of the most common pathogens of humans and animals, where it frequently colonizes skin and mucosal membranes. It is of major clinical importance as a nosocomial pathogen and causative agent of a wide array of diseases. Multidrug-resistant strains have become increasingly prevalent and represent a leading cause of morbidity and mortality. For this reason, novel strategies to combat multidrug-resistant pathogens are urgently needed. Bacteriophage-derived enzymes, so-called endolysins, and other peptidoglycan hydrolases with the ability to disrupt cell walls represent possible alternatives to conventional antibiotics. These lytic enzymes confer a high degree of host specificity and could potentially replace or be utilized in combination with antibiotics, with the aim to specifically treat infections caused by Gram-positive drug-resistant bacterial pathogens such as methicillin-resistant S. aureus . LysK is one of the best-characterized endolysins with activity against multiple staphylococcal species. Various approaches to further enhance the antibacterial efficacy and applicability of endolysins have been demonstrated. These approaches include the construction of recombinant endolysin derivatives and the development of novel delivery strategies for various applications, such as the production of endolysins in lactic acid bacteria and their conjugation to nanoparticles. These novel strategies are a major focus of this review. Copyright © 2017 American Society for Microbiology.

Celecoxib Enhances the Efficacy of Low-Dose Antibiotic Treatment against Polymicrobial Sepsis in Mice and Clinical Isolates of ESKAPE Pathogens

PubMed Central

Annamanedi, Madhavi; Varma, Gajapati Y. N.; Anuradha, K.; Kalle, Arunasree M.

2017-01-01

Treatment of multidrug resistant bacterial infections has been a great challenge globally. Previous studies including our study have highlighted the use of celecoxib, a non-steroidal anti-inflammatory drug in combination with antibiotic has decreased the minimal inhibitory concentration to limit Staphylococcus aureus infection. However, the efficacy of this combinatorial treatment against various pathogenic bacteria is not determined. Therefore, we have evaluated the potential use of celecoxib in combination with low doses of antibiotic in limiting Gram-positive and Gram-negative bacteria in vivo in murine polymicrobial sepsis developed by cecum ligation and puncture (CLP) method and against clinically isolated human ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species). The in vivo results clearly demonstrated a significant reduction in the bacterial load in different organs and in the inflammatory markers such as COX-2 and NF-κB via activation of SIRT1 in mice treated with imipenem, a choice of antibiotic for polymicrobial sepsis treatment. Combinatorial treatment of ampicillin and celecoxib was effective on clinical isolates of ESKAPE pathogens, 45% of tested clinical isolates showed more than 50% reduction in the colony forming units when compared to ampicillin alone. In conclusion, this non-traditional treatment strategy might be effective in clinic to reduce the dose of antibiotic to treat drug-resistant bacterial infections. PMID:28533769

Celecoxib Enhances the Efficacy of Low-Dose Antibiotic Treatment against Polymicrobial Sepsis in Mice and Clinical Isolates of ESKAPE Pathogens.

PubMed

Annamanedi, Madhavi; Varma, Gajapati Y N; Anuradha, K; Kalle, Arunasree M

2017-01-01

Treatment of multidrug resistant bacterial infections has been a great challenge globally. Previous studies including our study have highlighted the use of celecoxib, a non-steroidal anti-inflammatory drug in combination with antibiotic has decreased the minimal inhibitory concentration to limit Staphylococcus aureus infection. However, the efficacy of this combinatorial treatment against various pathogenic bacteria is not determined. Therefore, we have evaluated the potential use of celecoxib in combination with low doses of antibiotic in limiting Gram-positive and Gram-negative bacteria in vivo in murine polymicrobial sepsis developed by cecum ligation and puncture (CLP) method and against clinically isolated human ESKAPE pathogens ( Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa , and Enterobacter species). The in vivo results clearly demonstrated a significant reduction in the bacterial load in different organs and in the inflammatory markers such as COX-2 and NF-κB via activation of SIRT1 in mice treated with imipenem, a choice of antibiotic for polymicrobial sepsis treatment. Combinatorial treatment of ampicillin and celecoxib was effective on clinical isolates of ESKAPE pathogens, 45% of tested clinical isolates showed more than 50% reduction in the colony forming units when compared to ampicillin alone. In conclusion, this non-traditional treatment strategy might be effective in clinic to reduce the dose of antibiotic to treat drug-resistant bacterial infections.

Antimicrobial activity of broccoli (Brassica oleracea var. italica) cultivar Avenger against pathogenic bacteria, phytopathogenic filamentous fungi and yeast.

PubMed

Pacheco-Cano, R D; Salcedo-Hernández, R; López-Meza, J E; Bideshi, D K; Barboza-Corona, J E

2018-01-01

The objective of this study was to show whether the edible part of broccoli has antibacterial and antifungal activity against micro-organism of importance in human health and vegetable spoilage, and to test if this effect was partially due to antimicrobial peptides (AMPs). Crude extracts were obtained from florets and stems of broccoli cultivar Avenger and the inhibitory effect was demonstrated against pathogenic bacteria (Bacillus cereus, Staphylococcus xylosus, Staphylococcus aureus, Shigella flexneri, Shigella sonnei, Proteus vulgaris), phytopathogenic fungi (Colletotrichum gloeosporioides, Asperigillus niger) and yeasts (Candida albicans and Rhodotorula sp.). It was shown that samples treated with proteolytic enzymes had a reduction of approximately 60% in antibacterial activity against Staph. xylosus, suggesting that proteinaceous compounds might play a role in the inhibitory effect. Antimicrobial components in crude extracts were thermoresistant and the highest activity was observed under acidic conditions. It was shown that antifungal activity of broccoli's crude extracts might not be attributed to chitinases. Organic broccoli cultivar Avenger has antimicrobial activity against pathogenic bacteria, yeast and phytophatogenic fungi. Data suggest that this effect is partially due to AMPs. Broccoli's crude extracts have activity not only against pathogenic bacteria but also against phytophatogenic fungi of importance in agriculture. We suggest for first time that the inhibitory effect is probably due to AMPs. © 2017 The Society for Applied Microbiology.

Novel Strategy to Control the Warfighter’s Exposure to Polymicrobial Environments

DTIC Science & Technology

2015-09-30

RELEASE 13. SUPPLEMENTARY NOTES 14. ABSTRACT Bacteriocins active against clinically-relevant Pseudomonas aeruginosa, Staphylococcus aureus ...SUBJECT TERMS Bacteriocins, Antimicrobials, Pseudomonas aeruginosa, Staphylococcus aureus , Acinetobacter baumanii, Bacillus cereus 16. SECURITY...Pseudomonas aeruginosa, Staphylococcus aureus , Acinetobacter baumanni and Bacillus cereus (target pathogens for the proposed research). Summary

Multidrug resistant pathogens respond differently to the presence of co-pathogen, commensal, probiotic and host cells.

PubMed

Chan, Agnes P; Choi, Yongwook; Brinkac, Lauren M; Krishnakumar, Radha; DePew, Jessica; Kim, Maria; Hinkle, Mary K; Lesho, Emil P; Fouts, Derrick E

2018-06-05

In light of the ongoing antimicrobial resistance crisis, there is a need to understand the role of co-pathogens, commensals, and the local microbiome in modulating virulence and antibiotic resistance. To identify possible interactions that influence the expression of virulence or survival mechanisms in both the multidrug-resistant organisms (MDROs) and human host cells, unique cohorts of clinical isolates were selected for whole genome sequencing with enhanced assembly and full annotation, pairwise co-culturing, and transcriptome profiling. The MDROs were co-cultured in pairwise combinations either with: (1) another MDRO, (2) skin commensals (Staphylococcus epidermidis and Corynebacterium jeikeium), (3) the common probiotic Lactobacillus reuteri, and (4) human fibroblasts. RNA-Seq analysis showed distinct regulation of virulence and antimicrobial resistance gene responses across different combinations of MDROs, commensals, and human cells. Co-culture assays demonstrated that microbial interactions can modulate gene responses of both the target and pathogen/commensal species, and that the responses are specific to the identity of the pathogen/commensal species. In summary, bacteria have mechanisms to distinguish between friends, foe and host cells. These results provide foundational data and insight into the possibility of manipulating the local microbiome when treating complicated polymicrobial wound, intra-abdominal, or respiratory infections.

Longitudinal surveillance on antibiogram of important Gram-positive pathogens in Southern China, 2001 to 2015.

PubMed

Xu, Zhenbo; Xie, Jinhong; Peters, Brian M; Li, Bing; Li, Lin; Yu, Guangchao; Shirtliff, Mark E

2017-02-01

A longitudinal surveillance aimed to investigate the antibiogram of three genus of important Gram-positive pathogens in Southern China during 2001-2015. A total of 3849 Staphylococcus, Enterococcus and Streptococcus strains were isolated from Southern China during 2001-2015. Bacteria identification was performed by colony morphology, Gram staining, the API commercial kit and the Vitek 2 automated system. Antimicrobial susceptibility testing was determined by disk diffusion method and MIC method. As sampling site was concerned, 51.4% of Staphylococcus strains were isolated from sputum, whereas urinary tract remained the dominant infection site among Enterococcus and Streptococcus. According to the antimicrobial susceptibility, three genus of important Gram-positive pathogens showed high resistance against erythromycin, tetracycline, ciprofloxacin and clindamycin. Resistance rates to penicillins (penicillin, oxacillin, ampicillin) were high as well, with the exception of E. faecalis and Streptococcus. Overall, resistance rates against methicillin (oxacillin) were 63.2% in S. aureus and 76.2% in coagulase-negative Staphylococcus (CNS), along with continuous increases during the study. VRSA and vancomycin-resistant coagulase-negative Staphylococcus only appeared in 2011-2015. Sight decline was obtained for the vancomycin resistance of E. faecalis, while vancomycin-resistant E. faecium only appeared in 2011-2015, with its intermediate rate decreasing. Significant decrease in penicillin-resistant Streptococcus pneumonia (PRSP) was observed during studied period. Glycopeptide antibiotic remained highly effective to Staphylococcus, Enterococcus and Streptococcus (resistance rates <5%). Despite decline obtained for some antibiotic agents resistance during 2001-2015, antimicrobial resistance among Gram-positive pathogens still remained high in Southern China. This study may aid in the guidance for appropriate therapeutic strategy of infections caused by nosocomial pathogens. Copyright © 2016 Elsevier Ltd. All rights reserved.

Neighborhood diversity of potentially pathogenic bacteria in drinking water from the city of Maroua, Cameroon.

PubMed

Healy-Profitós, Jessica; Lee, Seungjun; Mouhaman, Arabi; Garabed, Rebecca; Moritz, Mark; Piperata, Barbara; Lee, Jiyoung

2016-06-01

This study examined the spatial variation of potential gastrointestinal pathogens within drinking water sources and home storage containers in four neighborhoods in Maroua, Cameroon. Samples were collected from source (n = 28) and home containers (n = 60) in each study neighborhood. Pathogen contamination was assessed using quantitative polymerase chain reaction, targeting Campylobacter spp., Shiga toxin producing Escherichia coli (virulence genes, stx1 and stx2), and Salmonella spp. Microbial source tracking (MST) targeted three different host-specific markers: HF183 (human), Rum2Bac (ruminant) and GFD (poultry) to identify contamination sources. Staphylococcus aureus and the tetracycline-resistance gene (tetQ) were assessed to measure human hand contact and presence of antibiotic-resistant bacteria. Pathogen/MST levels were compared statistically and spatially, and neighborhood variation was compared with previously collected demographic information. All the test fecal markers and pathogens (except Arcobacter) were detected in home and source samples. Two neighborhoods tested positive for most pathogens/MST while the others only tested positive for one or two. Spatial variation of pathogens/MST existed between sources, storage containers, and neighborhoods. Differing population density and ethno-economic characteristics could potentially explain variation. Future research should explore the influence of demographic and ethno-economic factors on water quality during microbial risk assessments in urban Africa.

Draft Genome Sequences of Escherichia coli Isolates from Wounded Military Personnel.

PubMed

Arivett, Brock A; Ream, Dave C; Fiester, Steven E; Kidane, Destaalem; Actis, Luis A

2016-08-11

Members of the Escherichia coli bacterial family have been grouped as ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogens because of their extensive drug resistance phenotypes and increasing threat to human health. The genomes of six extended-spectrum β-lactamase (ESBL)-producing E. coli strains isolated from wounded military personnel were sequenced and annotated. Copyright © 2016 Arivett et al.

The secreted polyketide boydone A is responsible for the anti-Staphylococcus aureus activity of Scedosporium boydii.

PubMed

Staerck, Cindy; Landreau, Anne; Herbette, Gaëtan; Roullier, Catherine; Bertrand, Samuel; Siegler, Benjamin; Larcher, Gérald; Bouchara, Jean-Philippe; Fleury, Maxime J J

2017-12-01

Usually living as a soil saprophyte, the filamentous fungus Scedosporium boydii may also cause various infections in human. Particularly, it is one of the major causative agents of fungal colonization of the airways in patients with cystic fibrosis (CF). To compete with other microorganisms in the environment, fungi have evolved sophisticated strategies, including the production of secondary metabolites with antimicrobial activity that may also help them to establish successfully within the respiratory tract of receptive hosts. Here, the culture filtrate from a human pathogenic strain of S. boydii was investigated searching for an antibacterial activity, mainly against the major CF bacterial pathogens. A high antibacterial activity against Staphylococcus aureus, including methicillin-resistant strains of this species, was observed. Bio-guided fractionation and analysis of the active fractions by nuclear magnetic resonance or by high-performance liquid chromatography and high-resolution electrospray ionization-mass spectrometry allowed us to identify boydone A as responsible for this antibacterial activity. Together, these results suggest that this six-membered cyclic polyketide could be one of the virulence factors of the fungus. Genes involved in the synthesis of this secreted metabolite are currently being identified in order to confirm the role of this polyketide in pathogenesis. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Primary lung abscess caused by Staphylococcus lugdunensis.

PubMed

Chou, Deng-Wei; Lee, Chao-Tai

2017-11-01

Staphylococcus lugdunensis, a strain of coagulase-negative staphylococci, is part of the normal flora of human skin but can cause multiple infections at various sites. This microorganism has emerged as a major human pathogen. However, no study has reported primary lung abscess caused by S. lugdunensis. A 54-year-old alcoholic man without relevant past medical history was admitted because of primary lung abscesses. Empirical amoxicillin/clavulanate therapy was initially administered; however, the patient had persistent pleuritic chest pain and fever. He subsequently underwent resection of the lung abscess and removal of exudative pleural effusion on the fourth hospital day. Histopathologic examination confirmed the diagnosis of lung abscess, and colonies of gram-positive bacteria were identified. The culture specimen from the abscess was positive for S. lugdunensis, which was susceptible to amoxicillin/clavulanate, cefazolin, ciprofloxacin, clindamycin, erythromycin, oxacillin, teicoplanin, tetracycline, and vancomycin. Following resection and 3 weeks of amoxicillin/clavulanate therapy, the patient eventually recovered well without relapse. This case report is the first to describe S. lugdunensis as a cause of primary lung abscess; this microorganism should be considered a potential monomicrobial pathogen in primary lung abscess. Copyright © 2017 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Staphylococcus aureus activates type I IFN signaling in mice and humans through the Xr repeated sequences of protein A

PubMed Central

Martin, Francis J.; Gomez, Marisa I.; Wetzel, Dawn M.; Memmi, Guido; O’Seaghdha, Maghnus; Soong, Grace; Schindler, Christian; Prince, Alice

2009-01-01

The activation of type I IFN signaling is a major component of host defense against viral infection, but it is not typically associated with immune responses to extracellular bacterial pathogens. Using mouse and human airway epithelial cells, we have demonstrated that Staphylococcus aureus activates type I IFN signaling, which contributes to its virulence as a respiratory pathogen. This response was dependent on the expression of protein A and, more specifically, the Xr domain, a short sequence–repeat region encoded by DNA that consists of repeated 24-bp sequences that are the basis of an internationally used epidemiological typing scheme. Protein A was endocytosed by airway epithelial cells and subsequently induced IFN-β expression, JAK-STAT signaling, and IL-6 production. Mice lacking IFN-α/β receptor 1 (IFNAR-deficient mice), which are incapable of responding to type I IFNs, were substantially protected against lethal S. aureus pneumonia compared with wild-type control mice. The profound immunological consequences of IFN-β signaling, particularly in the lung, may help to explain the conservation of multiple copies of the Xr domain of protein A in S. aureus strains and the importance of protein A as a virulence factor in the pathogenesis of staphylococcal pneumonia. PMID:19603548

Nfu facilitates the maturation of iron-sulfur proteins and participates in virulence in Staphylococcus aureus

PubMed Central

Mashruwala, Ameya A.; Pang, Yun Y.; Rosario-Cruz, Zuelay; Chahal, Harsimranjit K.; Benson, Meredith A.; Anzaldi-Mike, Laura L.; Skaar, Eric P.; Torres, Victor J.; Nauseef, William M.; Boyd, Jeffrey M.

2015-01-01

Summary The acquisition and metabolism of iron (Fe) by the human pathogen Staphylococcus aureus is critical for disease progression. S. aureus requires Fe to synthesize inorganic cofactors called iron-sulfur (Fe-S) clusters, which are required for functional Fe-S proteins. In this study we investigated the mechanisms utilized by S. aureus to metabolize Fe-S clusters. We identified that S. aureus utilizes the Suf biosynthetic system to synthesize Fe-S clusters and we provide genetic evidence suggesting that the sufU and sufB gene products are essential. Additional biochemical and genetic analyses identified Nfu as a Fe-S cluster carrier, which aids in the maturation of Fe-S proteins. We find that deletion of the nfu gene negatively impacts staphylococcal physiology and pathogenicity. A nfu mutant accumulates both increased intracellular non-incorporated Fe and endogenous reactive oxygen species (ROS) resulting in DNA damage. In addition, a strain lacking Nfu is sensitive to exogenously supplied ROS and reactive nitrogen species. Congruous with ex vivo findings, a nfu mutant strain is more susceptible to oxidative killing by human polymorphonuclear leukocytes and displays decreased tissue colonization in a murine model of infection. We conclude that Nfu is necessary for staphylococcal pathogenesis and establish Fe-S cluster metabolism as an attractive antimicrobial target. PMID:25388433

Evolution of community- and healthcare-associated methicillin-resistant Staphylococcus aureus☆

PubMed Central

Uhlemann, Anne-Catrin; Otto, Michael; Lowy, Franklin D.; DeLeo, Frank R.

2013-01-01

Staphylococcus aureus is a prominent cause of human infections globally. The high prevalence of infections is compounded by antibiotic resistance—a significant problem for treatment. Methicillin-resistant S. aureus (MRSA) is endemic in hospitals and healthcare facilities worldwide, and is an increasingly common cause of community-associated bacterial infections in industrialized countries. Although much focus is placed on the role of S. aureus as a human pathogen, it is in fact a human commensal organism that has had a relatively long coexistence with the human host. Many S. aureus infections can be explained by host susceptibility or other predisposing risk factors. On the other hand, the emergence/re-emergence of successful S. aureus clones (referred to as epidemic waves) suggests a rapid bacterial adaption and evolution, which includes the emergence of antibiotic resistance and increased virulence and/or transmissibility. It is within this context that we review our understanding of selected S. aureus epidemic waves, and highlight the use of genome sequencing as a means to better understand the evolution of each lineage. PMID:23648426

Virulence regulation in Staphylococcus aureus: the need for in vivo analysis of virulence factor regulation.

PubMed

Pragman, Alexa A; Schlievert, Patrick M

2004-10-01

Staphylococcus aureus is a pathogenic microorganism that is responsible for a wide variety of clinical infections. These infections can be relatively mild, but serious, life-threatening infections may result from the expression of staphylococcal virulence factors that are coordinated by virulence regulators. Much work has been done to characterize the actions of staphylococcal virulence regulators in broth culture. Recently, several laboratories showed that transcriptional analyses of virulence regulators in in vivo animal models or in human infection did not correlate with transcriptional analyses accomplished in vitro. In describing the differences between in vitro and in vivo transcription of staphylococcal virulence regulators, we hope to encourage investigators to study virulence regulators using infection models whenever possible.

Adhesion, invasion and evasion: the many functions of the surface proteins of Staphylococcus aureus

PubMed Central

Foster, Timothy J.; Geoghegan, Joan A.; Ganesh, Vannakambadi K.; Höök, Magnus

2014-01-01

Staphylococcus aureus is an important opportunistic pathogen and persistently colonizes about 20% of the human population. Its surface is ‘decorated’ with proteins that are covalently anchored to the cell wall peptidoglycan. Structural and functional analysis has identified four distinct classes of surface proteins, of which microbial surface component recognizing adhesive matrix molecules (MSCRAMMs) are the largest class. These surface proteins have numerous functions, including adhesion to and invasion of host cells and tissues, evasion of immune responses and biofilm formation. Thus, cell wall-anchored proteins are essential virulence factors for the survival of S. aureus in the commensal state and during invasive infections, and targeting them with vaccines could combat S. aureus infections. PMID:24336184

Improved understanding of factors driving methicillin-resistant Staphylococcus aureus epidemic waves

PubMed Central

Chatterjee, Som S; Otto, Michael

2013-01-01

Methicillin-resistant Staphylococcus aureus (MRSA) remains one of the most important causes of nosocomial infections worldwide. Since the global spread of MRSA in the 1960s, MRSA strains have evolved with increased pathogenic potential. Notably, some strains are now capable of causing persistent infections not only in hospitalized patients but also in healthy individuals in the community. Furthermore, MRSA is increasingly associated with infections among livestock-associated workers, primarily because of transmission from animals to humans. Moreover, many MRSA strains have gained resistance to most available antibiotics. In this review, we will present current knowledge on MRSA epidemiology and discuss new endeavors being undertaken to understand better the molecular and epidemiological underpinnings of MRSA outbreaks. PMID:23861600

Emerging Functions for the Staphylococcus aureus RNome

PubMed Central

Felden, Brice

2013-01-01

Staphylococcus aureus is a leading pathogen for animals and humans, not only being one of the most frequently isolated bacteria in hospital-associated infections but also causing diseases in the community. To coordinate the expression of its numerous virulence genes for growth and survival, S. aureus uses various signalling pathways that include two-component regulatory systems, transcription factors, and also around 250 regulatory RNAs. Biological roles have only been determined for a handful of these sRNAs, including cis, trans, and cis-trans acting RNAs, some internally encoding small, functional peptides and others possessing dual or multiple functions. Here we put forward an inventory of these fascinating sRNAs; the proteins involved in their activities; and those involved in stress response, metabolisms, and virulence. PMID:24348246

Presence of Laminin Receptors in Staphylococcus aureus

NASA Astrophysics Data System (ADS)

Lopes, J. D.; Dos Reis, M.; Brentani, R. R.

1985-07-01

A characteristic feature of infection by Staphylococcus aureus is bloodstream invasion and widespread metastatic abscess formation. The ability to extravasate, which entails crossing the vascular basement membrane, appears to be critical for the organism's pathogenicity. Extravasation by normal and neoplastic mammalian cells has been correlated with the presence of specific cell surface receptors for the basement membrane glycoprotein laminin. Similar laminin receptors were found in Staphylococcus aureus but not in Staphylococcus epidermidis, a noninvasive pathogen. There were about 100 binding sites per cell, with an apparent binding affinity of 2.9 nanomolar. The molecular weight of the receptor was 50,000 and pI was 4.2. Eukaryotic laminin receptors were visualized by means of the binding of S. aureus in the presence of laminin. Prokaryotic and eukaryotic invasive cells might utilize similar, if not identical, mechanisms for invasion.

Brucella sp. vertebral osteomyelitis with intercurrent fatal Staphylococcus aureus toxigenic enteritis in a bottlenose dolphin (Tursiops truncatus)

PubMed Central

Goertz, Caroline E. C.; Frasca, Salvatore; Bohach, Gregory A.; Cowan, Daniel F.; Buck, John D.; French, Richard A.; De Guise, Sylvain; Maratea, Jennifer; Hinckley, Lynn; Ewalt, Darla; Schlievert, Patrick M.; Karst, Sheila M.; Deobald, Claudia F.; St. Aubin, David J.; Dunn, J. Lawrence

2013-01-01

A previously beach-stranded, juvenile, male, bottlenose dolphin (Tursiops truncatus) was diagnosed with vertebral osteomyelitis of unknown etiology. Antemortem serological testing suggested past or current Brucella sp. infection; however, this could not be confirmed prior to death despite multiple isolation attempts from aspirates, blood, and biopsies. Systemic antibiotics were administered for over a year to control the suspected infection; however, the animal succumbed peracutely to a highly pathogenic, enterotoxin-secreting Staphylococcus sp. Gross necropsy findings included a fistulous tract leading to locally extensive osteomyelitis of a coccygeal vertebra with sequestra and osteophytes from which a Brucella species was isolated. Histopathological examination of intestine revealed pseudomembranous enteritis with a uniform population of intraluminal Gram-positive cocci. Staphylococcus aureus was isolated in pure culture from the intestine and tested positive for the staphylococcal enterotoxin A gene by polymerase chain reaction analysis. Serum taken shortly before death had endotoxin and elevated antibody titers to staphylococcal enterotoxin A when compared to samples collected during a period of apparent good health eighteen months earlier. The isolation of a pyrogenic toxin superantigen-producing staphylococcal isolate, clinical signs, and diagnostic findings in this animal resembled some of those noted in human toxic shock syndrome. The present case highlights the clinical challenges of treating chronic illnesses, complications of long-term antibiotic use, and promotion of pathogenic strains in cases of prolonged rehabilitation of marine mammals. PMID:21908337

Selection of suitable reference genes for gene expression studies in Staphylococcus capitis during growth under erythromycin stress.

PubMed

Cui, Bintao; Smooker, Peter M; Rouch, Duncan A; Deighton, Margaret A

2016-08-01

Accurate and reproducible measurement of gene transcription requires appropriate reference genes, which are stably expressed under different experimental conditions to provide normalization. Staphylococcus capitis is a human pathogen that produces biofilm under stress, such as imposed by antimicrobial agents. In this study, a set of five commonly used staphylococcal reference genes (gyrB, sodA, recA, tuf and rpoB) were systematically evaluated in two clinical isolates of Staphylococcus capitis (S. capitis subspecies urealyticus and capitis, respectively) under erythromycin stress in mid-log and stationary phases. Two public software programs (geNorm and NormFinder) and two manual calculation methods, reference residue normalization (RRN) and relative quantitative (RQ), were applied. The potential reference genes selected by the four algorithms were further validated by comparing the expression of a well-studied biofilm gene (icaA) with phenotypic biofilm formation in S. capitis under four different experimental conditions. The four methods differed considerably in their ability to predict the most suitable reference gene or gene combination for comparing icaA expression under different conditions. Under the conditions used here, the RQ method provided better selection of reference genes than the other three algorithms; however, this finding needs to be confirmed with a larger number of isolates. This study reinforces the need to assess the stability of reference genes for analysis of target gene expression under different conditions and the use of more than one algorithm in such studies. Although this work was conducted using a specific human pathogen, it emphasizes the importance of selecting suitable reference genes for accurate normalization of gene expression more generally.

Penicillin binding protein 3 of Staphylococcus aureus NCTC 8325-4 binds and activates human plasminogen.

PubMed

Kylväjä, Riikka; Ojalehto, Tuomas; Kainulainen, Veera; Virkola, Ritva; Westerlund-Wikström, Benita

2016-08-04

Staphylococcus aureus is a versatile pathogen expressing a number of virulence-associated adhesive molecules. In a previous study, we generated in a secretion-competent Escherichia coli strain a library of random FLAG-tag positive (FTP) polypeptides of S. aureus. To identify adhesive proteins and gain additional knowledge on putative virulence factors of S. aureus, we here screened the FTP library against human serum proteins. Staphylococcus aureus NCTC 8325-4, origin of the FTP library, adhered to immobilized plasminogen in vitro. In an enzyme-linked immunoassay a C-terminal part of penicillin binding protein 3 (PBP3), included in the FTP library, bound to immobilized plasminogen. We expressed and purified full-length PBP3 and its C-terminal fragments as recombinant proteins. In a time-resolved fluorometry-based assay the PBP3 polypeptides bound to immobilized plasminogen. The polypeptides enhanced formation of plasmin from plasminogen as analyzed by cleavage of a chromogenic plasmin substrate. The present findings, although preliminary, demonstrate reliably that S. aureus NCTC 8325-4 adheres to immobilized plasminogen in vitro and that the adhesion may be mediated by a C-terminal fragment of the PBP3 protein. The full length PBP3 and the penicillin binding C-terminal domain of PBP3 expressed as recombinant proteins bound plasminogen and activated plasminogen to plasmin. These phenomena were inhibited by the lysine analogue ε-aminocaproic acid suggesting that the binding is mediated by lysine residues. A detailed molecular description of surface molecules enhancing the virulence of S. aureus will aid in understanding of its pathogenicity and help in design of antibacterial drugs in the future.

Human platelet gel supernatant inactivates opportunistic wound pathogens on skin.

PubMed

Edelblute, Chelsea M; Donate, Amy L; Hargrave, Barbara Y; Heller, Loree C

2015-01-01

Activation of human platelets produces a gel-like substance referred to as platelet rich plasma or platelet gel. Platelet gel is used clinically to promote wound healing; it also exhibits antimicrobial properties that may aid in the healing of infected wounds. The purpose of this study was to quantify the efficacy of human platelet gel against the opportunistic bacterial wound pathogens Acinetobacter baumannii, Pseudomonas aeruginosa, and Staphylococcus aureus on skin. These opportunistic pathogens may exhibit extensive antibiotic resistance, necessitating the development of alternative treatment options. The antimicrobial efficacy of platelet gel supernatants was quantified using an in vitro broth dilution assay, an ex vivo inoculated skin assay, and in an in vivo skin decontamination assay. Human platelet gel supernatants were highly bactericidal against A. baumannii and moderately but significantly bactericidal against S. aureus in vitro and in the ex vivo skin model. P. aeruginosa was not inactivated in vitro; a low but significant inactivation level was observed ex vivo. These supernatants were quite effective at inactivating a model organism on skin in vivo. These results suggest application of platelet gel has potential clinical applicability, not only in the acceleration of wound healing, but also against relevant bacteria causing wound infections.

Extensive horizontal gene transfer during Staphylococcus aureus co-colonization in vivo.

PubMed

McCarthy, Alex J; Loeffler, Anette; Witney, Adam A; Gould, Katherine A; Lloyd, David H; Lindsay, Jodi A

2014-09-25

Staphylococcus aureus is a commensal and major pathogen of humans and animals. Comparative genomics of S. aureus populations suggests that colonization of different host species is associated with carriage of mobile genetic elements (MGE), particularly bacteriophages and plasmids capable of encoding virulence, resistance, and immune evasion pathways. Antimicrobial-resistant S. aureus of livestock are a potential zoonotic threat to human health if they adapt to colonize humans efficiently. We utilized the technique of experimental evolution and co-colonized gnotobiotic piglets with both human- and pig-associated variants of the lineage clonal complex 398, and investigated growth and genetic changes over 16 days using whole genome sequencing. The human isolate survived co-colonization on piglets more efficiently than in vitro. During co-colonization, transfer of MGE from the pig to the human isolate was detected within 4 h. Extensive and repeated transfer of two bacteriophages and three plasmids resulted in colonization with isolates carrying a wide variety of mobilomes. Whole genome sequencing of progeny bacteria revealed no acquisition of core genome polymorphisms, highlighting the importance of MGE. Staphylococcus aureus bacteriophage recombination and integration into novel sites was detected experimentally for the first time. During colonization, clones coexisted and diversified rather than a single variant dominating. Unexpectedly, each piglet carried unique populations of bacterial variants, suggesting limited transmission of bacteria between piglets once colonized. Our data show that horizontal gene transfer occurs at very high frequency in vivo and significantly higher than that detectable in vitro. © The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Antibiotic Resistant and Virulence Determinants of Staphylococcus haemolyticus C10A as Revealed by Whole Genome Sequencing.

PubMed

Chan, Kok-Gan; Ng, Kim Tien; Chong, Teik Min; Pang, Yong Kek; Kamarulzaman, Adeeba; Yin, Wai-Fong; Tee, Kok Keng

2015-01-01

Staphylococcus haemolyticus is one of the pathogens that harbor a high level of antibiotic resistance. Here, we highlighted the potential determinants for multidrug resistance and virulence from the draft genome of Staphylococcus haemolyticus strain C10A, isolated from a patient with chronic obstructive pulmonary disease exacerbation.

Staphylococcus epidermidis Biofilms: Functional Molecules, Relation to Virulence, and Vaccine Potential

NASA Astrophysics Data System (ADS)

Mack, Dietrich; Davies, Angharad P.; Harris, Llinos G.; Knobloch, Johannes K. M.; Rohde, Holger

Medical device-associated infections, most frequently caused by Staphylococcus epidermidis and Staphylococcus aureus, are of increasing importance in modern medicine. The formation of adherent, multilayered bacterial biofilms is crucial in the pathogenesis of these infections. Polysaccharide intercellular adhesin (PIA), a homoglycan of β-1,6-linked 2-acetamido-2-deoxy-d-glucopyranosyl residues, of which about 15% are non-N-acetylated, is central to biofilm accumulation in staphylococci. It transpires that polysaccharides - structurally very similar to PIA - are also key to biofilm formation in a number of other organisms including the important human pathogens Escherichia coli, Aggregatibacter (Actinobacillus) actinomycetemcomitans, Yersinia pestis, and Bordetella spp. Apparently, synthesis of PIA and related polysaccharides is a general feature important for biofilm formation in diverse bacterial genera. Current knowledge about the structure and biosynthesis of PIA and related polysaccharides is reviewed. Additionally, information on their role in pathogenesis of biomaterial-related and other type of infections and the potential use of PIA and related compounds for prevention of infection is evaluated.

Draft Genome Sequences of Pseudomonas aeruginosa Isolates from Wounded Military Personnel.

PubMed

Arivett, Brock A; Ream, Dave C; Fiester, Steven E; Kidane, Destaalem; Actis, Luis A

2016-08-11

Pseudomonas aeruginosa, a Gram-negative bacterium that causes severe hospital-acquired infections, is grouped as an ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogen because of its extensive drug resistance phenotypes and effects on human health worldwide. Five multidrug resistant P. aeruginosa strains isolated from wounded military personnel were sequenced and annotated in this work. Copyright © 2016 Arivett et al.

Draft Genome Sequences of Acinetobacter baumannii Isolates from Wounded Military Personnel.

PubMed

Arivett, Brock A; Ream, Dave C; Fiester, Steven E; Kidane, Destaalem; Actis, Luis A

2016-08-25

Acinetobacter baumannii is a Gram-negative bacterium capable of causing hospital-acquired infections that has been grouped with Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species as ESKAPE pathogens because of their extensive drug resistance phenotypes and increasing risk to human health. Twenty-four multidrug-resistant A. baumannii strains isolated from wounded military personnel were sequenced and annotated. Copyright © 2016 Arivett et al.

Global analysis of community-associated methicillin-resistant Staphylococcus aureus exoproteins reveals molecules produced in vitro and during infection

PubMed Central

Burlak, Christopher; Hammer, Carl H; Robinson, Mary-Ann; Whitney, Adeline R; McGavin, Martin J; Kreiswirth, Barry N; DeLeo, Frank R

2007-01-01

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is a threat to human health worldwide. Although progress has been made, mechanisms of CA-MRSA pathogenesis are poorly understood and a comprehensive analysis of CA-MRSA exoproteins has not been conducted. To address that deficiency, we used proteomics to identify exoproteins made by MW2 (USA400) and LAC (USA300) during growth in vitro. Two hundred and fifty unique exoproteins were identified by 2-dimensional gel electrophoresis coupled with automated direct infusion-tandem mass spectrometry (ADI-MS/MS) analysis. Eleven known virulence-related exoproteins differed in abundance between the strains, including alpha-haemolysin (Hla), collagen adhesin (Cna), staphylokinase (Sak), coagulase (Coa), lipase (Lip), enterotoxin C3 (Sec3), enterotoxin Q (Seq), V8 protease (SspA) and cysteine protease (SspB). Mice infected with MW2 or LAC produced antibodies specific for known or putative virulence factors, such as autolysin (Atl), Cna, Ear, ferritin (Ftn), Lip, 1-phosphatidylinositol phosphodiesterase (Plc), Sak, Sec3 and SspB, indicating the exoproteins are made during infection in vivo. We used confocal microscopy to demonstrate aureolysin (Aur), Hla, SspA and SspB are produced following phagocytosis by human neutrophils, thereby linking exoprotein production in vitro with that during host–pathogen interaction. We conclude that the exoproteins identified herein likely account in part for the success of CA-MRSA as a human pathogen. PMID:17217429

A peptide resource for the analysis of Staphylococcus aureus in host pathogen interaction studies

PubMed Central

Depke, Maren; Michalik, Stephan; Rabe, Alexander; Surmann, Kristin; Brinkmann, Lars; Jehmlich, Nico; Bernhardt, Jörg; Hecker, Michael; Wollscheid, Bernd; Sun, Zhi; Moritz, Robert L.; Völker, Uwe; Schmidt, Frank

2016-01-01

Staphylococcus aureus is an opportunistic human pathogen, which can cause life-threatening disease. Proteome analyses of the bacterium can provide new insights into its pathophysiology and important facets of metabolic adaptation and, thus, aid the recognition of targets for intervention. However, the value of such proteome studies increases with their comprehensiveness. We present an MS–driven, proteome-wide characterization of the strain S. aureus HG001. Combining 144 high precision proteomic data sets, we identified 19 109 peptides from 2088 distinct S. aureus HG001 proteins, which account for 72% of the predicted ORFs. Peptides were further characterized concerning pI, GRAVY, and detectability scores in order to understand the low peptide coverage of 8.7% (19 109 out of 220 245 theoretical peptides). The high quality peptide-centric spectra have been organized into a comprehensive peptide fragmentation library (SpectraST) and used for identification of S. aureus-typic peptides in highly complex host–pathogen interaction experiments, which significantly improved the number of identified S. aureus proteins compared to a MASCOT search. This effort now allows the elucidation of crucial pathophysiological questions in S. aureus-specific host–pathogen interaction studies through comprehensive proteome analysis. The S. aureus-specific spectra resource developed here also represents an important spectral repository for SRM or for data-independent acquisition MS approaches. All MS data have been deposited in the ProteomeXchange with identifier PXD000702 (http://proteomecentral.proteomexchange.org/dataset/PXD000702). PMID:26224020

A peptide resource for the analysis of Staphylococcus aureus in host-pathogen interaction studies.

PubMed

Depke, Maren; Michalik, Stephan; Rabe, Alexander; Surmann, Kristin; Brinkmann, Lars; Jehmlich, Nico; Bernhardt, Jörg; Hecker, Michael; Wollscheid, Bernd; Sun, Zhi; Moritz, Robert L; Völker, Uwe; Schmidt, Frank

2015-11-01

Staphylococcus aureus is an opportunistic human pathogen, which can cause life-threatening disease. Proteome analyses of the bacterium can provide new insights into its pathophysiology and important facets of metabolic adaptation and, thus, aid the recognition of targets for intervention. However, the value of such proteome studies increases with their comprehensiveness. We present an MS-driven, proteome-wide characterization of the strain S. aureus HG001. Combining 144 high precision proteomic data sets, we identified 19 109 peptides from 2088 distinct S. aureus HG001 proteins, which account for 72% of the predicted ORFs. Peptides were further characterized concerning pI, GRAVY, and detectability scores in order to understand the low peptide coverage of 8.7% (19 109 out of 220 245 theoretical peptides). The high quality peptide-centric spectra have been organized into a comprehensive peptide fragmentation library (SpectraST) and used for identification of S. aureus-typic peptides in highly complex host-pathogen interaction experiments, which significantly improved the number of identified S. aureus proteins compared to a MASCOT search. This effort now allows the elucidation of crucial pathophysiological questions in S. aureus-specific host-pathogen interaction studies through comprehensive proteome analysis. The S. aureus-specific spectra resource developed here also represents an important spectral repository for SRM or for data-independent acquisition MS approaches. All MS data have been deposited in the ProteomeXchange with identifier PXD000702 (http://proteomecentral.proteomexchange.org/dataset/PXD000702). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nonribosomal peptide synthetase biosynthetic clusters of ESKAPE pathogens.

PubMed

Gulick, Andrew M

2017-08-02

Covering: up to 2017.Natural products are important secondary metabolites produced by bacterial and fungal species that play important roles in cellular growth and signaling, nutrient acquisition, intra- and interspecies communication, and virulence. A subset of natural products is produced by nonribosomal peptide synthetases (NRPSs), a family of large, modular enzymes that function in an assembly line fashion. Because of the pharmaceutical activity of many NRPS products, much effort has gone into the exploration of their biosynthetic pathways and the diverse products they make. Many interesting NRPS pathways have been identified and characterized from both terrestrial and marine bacterial sources. Recently, several NRPS pathways in human commensal bacterial species have been identified that produce molecules with antibiotic activity, suggesting another source of interesting NRPS pathways may be the commensal and pathogenic bacteria that live on the human body. The ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) have been identified as a significant cause of human bacterial infections that are frequently multidrug resistant. The emerging resistance profile of these organisms has prompted calls from multiple international agencies to identify novel antibacterial targets and develop new approaches to treat infections from ESKAPE pathogens. Each of these species contains several NRPS biosynthetic gene clusters. While some have been well characterized and produce known natural products with important biological roles in microbial physiology, others have yet to be investigated. This review catalogs the NRPS pathways of ESKAPE pathogens. The exploration of novel NRPS products may lead to a better understanding of the chemical communication used by human pathogens and potentially to the discovery of novel therapeutic approaches.

[New insight into bacterial zoonotic pathogens posing health hazards to humans].

PubMed

Ciszewski, Marcin; Czekaj, Tomasz; Szewczyk, Eligia Maria

2014-01-01

This article presents the problem of evolutionary changes of zoonotic pathogens responsible for human diseases. Everyone is exposed to the risk of zoonotic infection, particularly employees having direct contact with animals, i.e. veterinarians, breeders, butchers and workers of animal products' processing industry. The article focuses on pathogens monitored by the European Centre for Disease Prevention and Control (ECDC), which has been collecting statistical data on zoonoses from all European Union countries for 19 years and publishing collected data in annual epidemiological reports. Currently, the most important 11 pathogens responsible for causing human zoonotic diseases are being monitored, of which seven are bacteria: Salmonella spp., Campylobacter spp., Listeria monocytogenes, Mycobacterium bovis, Brucella spp., Coxiella burnetti and Verotoxin-producing E. coli (VTEC)/Shiga-like toxin producing E. coli (STEC). As particularly important are considered foodborne pathogens. The article also includes new emerging zoonotic bacteria, which are not currently monitored by ECDC but might pose a serious epidemiological problem in a foreseeable future: Streptococcus iniae, S. suis, S. dysgalactiae and staphylococci: Staphylococcus intermedius, S. pseudintermedius. Those species have just crossed the animal-human interspecies barrier. The exact mechanism of this phenomenon remains unknown, it is connected, however, with genetic variability, capability to survive in changing environment. These abilities derive from DNA rearrangement and horizontal gene transfer between bacterial cells. Substantial increase in the number of scientific publications on this subject, observed over the last few years, illustrates the importance of the problem.

Phenol-Soluble Modulin Toxins of Staphylococcus haemolyticus

PubMed Central

Da, Fei; Joo, Hwang-Soo; Cheung, Gordon Y. C.; Villaruz, Amer E.; Rohde, Holger; Luo, Xiaoxing; Otto, Michael

2017-01-01

Coagulase-negative staphylococci (CoNS) are important nosocomial pathogens and the leading cause of sepsis. The second most frequently implicated species, after Staphylococcus epidermidis, is Staphylococcus haemolyticus. However, we have a significant lack of knowledge about what causes virulence of S. haemolyticus, as virulence factors of this pathogen have remained virtually unexplored. In contrast to the aggressive pathogen Staphylococcus aureus, toxin production has traditionally not been associated with CoNS. Recent findings have suggested that phenol-soluble modulins (PSMs), amphipathic peptide toxins with broad cytolytic activity, are widespread in staphylococci, but there has been no systematic assessment of PSM production in CoNS other than S. epidermidis. Here, we identified, purified, and characterized PSMs of S. haemolyticus. We found three PSMs of the β-type, which correspond to peptides that before were described to have anti-gonococcal activity. We also detected an α-type PSM that has not previously been described. Furthermore, we confirmed that S. haemolyticus does not produce a δ-toxin, as results from genome sequencing had indicated. All four S. haemolyticus PSMs had strong pro-inflammatory activity, promoting neutrophil chemotaxis. Notably, we identified in particular the novel α-type PSM, S. haemolyticus PSMα, as a potent hemolysin and leukocidin. For the first time, our study describes toxins of this important staphylococcal pathogen with the potential to have a significant impact on virulence during blood infection and sepsis. PMID:28596942

Phenol-Soluble Modulin Toxins of Staphylococcus haemolyticus.

PubMed

Da, Fei; Joo, Hwang-Soo; Cheung, Gordon Y C; Villaruz, Amer E; Rohde, Holger; Luo, Xiaoxing; Otto, Michael

2017-01-01

Coagulase-negative staphylococci (CoNS) are important nosocomial pathogens and the leading cause of sepsis. The second most frequently implicated species, after Staphylococcus epidermidis , is Staphylococcus haemolyticus . However, we have a significant lack of knowledge about what causes virulence of S. haemolyticus , as virulence factors of this pathogen have remained virtually unexplored. In contrast to the aggressive pathogen Staphylococcus aureus , toxin production has traditionally not been associated with CoNS. Recent findings have suggested that phenol-soluble modulins (PSMs), amphipathic peptide toxins with broad cytolytic activity, are widespread in staphylococci, but there has been no systematic assessment of PSM production in CoNS other than S. epidermidis . Here, we identified, purified, and characterized PSMs of S. haemolyticus . We found three PSMs of the β-type, which correspond to peptides that before were described to have anti-gonococcal activity. We also detected an α-type PSM that has not previously been described. Furthermore, we confirmed that S. haemolyticus does not produce a δ-toxin, as results from genome sequencing had indicated. All four S. haemolyticus PSMs had strong pro-inflammatory activity, promoting neutrophil chemotaxis. Notably, we identified in particular the novel α-type PSM, S. haemolyticus PSMα, as a potent hemolysin and leukocidin. For the first time, our study describes toxins of this important staphylococcal pathogen with the potential to have a significant impact on virulence during blood infection and sepsis.

MICROBIOLOGICAL ASSESSMENT OF LETTUCE SALADS AND ANTIMICROBIAL RESISTANCE OF STAPHYLOCOCCUS SPP.

PubMed

Guimarães César, Josi; Madruga Peres, Andriele; Pereira das Neves, Caroline; Tupiniquim Freitas de Abreu, Érica; Fagundes de Mello, Jozi; Nunes Moreira, Ângela; Lameiro Rodrigues, Kelly

2015-11-01

self-service restaurants in which food is served ready to be consumed are liable to have some products contaminated by pathogenic microorganisms causing food-transmitted diseases. evaluates the microbiological quality of lettuce salads in restaurants in Pelotas RS Brazil by counts of thermo-tolerant coliforms, E. coli, Staphylococcus spp. and detection of Salmonella spp. Antimicrobial resistance of Staphylococcus spp. isolates are also assessed. thirty-six samples of lettuce salads were collected from nine restaurants and thermotolerant coliforms, Escherichia coli and Staphylococcus spp. were quantified, coupled to a research on Salmonella spp., following methodology by the Bacteriological Analytical Manual. Staphylococcus spp. isolates underwent antimicrobial resistance test by the disc-diffusion method. results showed that 61.1% of the salad samples contained more thermotolerant coliforms than allowed by Brazilian legislation and E. coli was confirmed in 5.6% of the samples. Positive and negative coagulase Staphylococcus occurred respectively in 5.6% and 77.8% of isolates, but no sample had Salmonella spp. Further, 56.7% of the thirty isolates of Staphylococcus spp. tested were resistant to penicillin; 46.7% to oxacillin; 26.7% to erythromycin and 23.3% were multi- resistant. inadequate quality of the salad was due to pathogenic microorganisms, while Staphylococcus spp. isolates had a high percentage of antimicrobial resistance. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

Cigarette smoke increases Staphylococcus aureus biofilm formation via oxidative stress.

PubMed

Kulkarni, Ritwij; Antala, Swati; Wang, Alice; Amaral, Fábio E; Rampersaud, Ryan; Larussa, Samuel J; Planet, Paul J; Ratner, Adam J

2012-11-01

The strong epidemiological association between cigarette smoke (CS) exposure and respiratory tract infections is conventionally attributed to immunosuppressive and irritant effects of CS on human cells. Since pathogenic bacteria such as Staphylococcus aureus are members of the normal microbiota and reside in close proximity to human nasopharyngeal cells, we hypothesized that bioactive components of CS might affect these organisms and potentiate their virulence. Using Staphylococcus aureus as a model organism, we observed that the presence of CS increased both biofilm formation and host cell adherence. Analysis of putative molecular pathways revealed that CS exposure decreased expression of the quorum-sensing agr system, which is involved in biofilm dispersal, and increased transcription of biofilm inducers such as sarA and rbf. CS contains bioactive compounds, including free radicals and reactive oxygen species, and we observed transcriptional induction of bacterial oxidoreductases, including superoxide dismutase, following exposure. Moreover, pretreatment of CS with an antioxidant abrogated CS-mediated enhancement of biofilms. Exposure of bacteria to hydrogen peroxide alone increased biofilm formation. These observations are consistent with the hypothesis that CS induces staphylococcal biofilm formation in an oxidant-dependent manner. CS treatment induced transcription of fnbA (encoding fibronectin binding protein A), leading to increased binding of CS-treated staphylococci to immobilized fibronectin and increased adherence to human cells. These observations indicate that the bioactive effects of CS may extend to the resident microbiota of the nasopharynx, with implications for the pathogenesis of respiratory infection in CS-exposed humans.

Screening of antibacterial activity of lactic acid bacteria against different pathogens found in vacuum-packaged meat products.

PubMed

Awaisheh, Saddam S; Ibrahim, Salam A

2009-11-01

The objective of this work was to screen the antibacterial activity of lactic acid bacteria (LAB) isolated from different sources against different pathogens found in ready-to-eat vacuum-packaged meat products (RTE-VPMP). LAB were isolated from human, RTE-VPMP, fermented vegetables, and dairy samples. These isolates were assessed for their antibacterial activity against Escherichia coli O157:H7, Salmonella spp., Listeria monocytogenes, and Staphylococcus aureus using spot on lawn technique. Six LAB isolates-three from a human source, two from a RTE-VPMP source, and one from a fermented vegetable source-were found to be effective against all pathogenic strains. Antibacterial activities of cell-free neutral supernatant broths of these isolates were assessed against the different pathogenic strains to confirm bacteriocin production. All six isolates were effective against all pathogenic strains. LAB isolates from the human source had the highest antibacterial activity and were significantly more effective than other LAB isolates, with the inhibition zone ranging from 14 to 22 mm. Inhibition zones of RTE-VPMP LAB isolates were lower than those of human origin (inhibition zone range, 11-17 mm). The lowest activities were for the fermented vegetable isolate, for which inhibition zones ranged from 11 to 15 mm. The three isolates of human origin were identified as L. acidophilus, L. casei, and L. reuteri; the two isolates from RTE-VPMP source were both L. sake; and the one isolate of fermented vegetable origin was L. plantarum. Our results showed that nonmeat product-sourced LAB were effective against several foodborne pathogens, which suggests that they could be used as natural biopreservatives in many RTE-VPMP produced in Jordan.

A Rapid and Simple Real-Time PCR Assay for Detecting Foodborne Pathogenic Bacteria in Human Feces.

PubMed

Hanabara, Yutaro; Ueda, Yutaka

2016-11-22

A rapid, simple method for detecting foodborne pathogenic bacteria in human feces is greatly needed. Here, we examined the efficacy of a method that employs a combination of a commercial PCR master mix, which is insensitive to PCR inhibitors, and a DNA extraction method which used sodium dodecyl benzene sulfonate (SDBS), and Tween 20 to counteract the inhibitory effects of SDBS on the PCR assay. This method could detect the target genes (stx1 and stx2 of enterohemorrhagic Escherichia coli, invA of Salmonella Enteritidis, tdh of Vibrio parahaemolyticus, gyrA of Campylobacter jejuni, ceuE of Campylobacter coli, SEA of Staphylococcus aureus, ces of Bacillus cereus, and cpe of Clostridium perfringens) in a fecal suspension containing 1.0 × 10 1 to 1.0 × 10 3 CFU/ml. Furthermore, the assay was neither inhibited nor influenced by individual differences among the fecal samples of 10 subjects or fecal concentration (40-160 mg/ml in the fecal suspension). When we attempted to detect the genes of pathogenic bacteria in 4 actual clinical cases, we found that this method was more sensitive than standard culture method. These results showed that this assay is a rapid, simple detection method for foodborne pathogenic bacteria in human feces.

Community-acquired methicillin-resistant Staphylococcus aureus: an emerging cause of acute bacterial parotitis.

PubMed

Nicolasora, Nelson P; Zacharek, Mark A; Malani, Anurag N

2009-02-01

Staphylococcus aureus has long been recognized as a cause of acute bacterial parotitis. A case of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) parotitis is presented, highlighting the emergence of this increasingly important pathogen to cause a wide variety of infections. Also reviewed are the salient clinical and microbiologic features of this novel infection.

Fibrinogen-binding and platelet-aggregation activities of a Lactobacillus salivarius septicaemia isolate are mediated by a novel fibrinogen-binding protein.

PubMed

Collins, James; van Pijkeren, Jan-Peter; Svensson, Lisbeth; Claesson, Marcus J; Sturme, Mark; Li, Yin; Cooney, Jakki C; van Sinderen, Douwe; Walker, Alan W; Parkhill, Julian; Shannon, Oonagh; O'Toole, Paul W

2012-09-01

The marketplace for probiotic foods is burgeoning, measured in billions of euro per annum. It is imperative, however, that all bacterial strains are fully assessed for human safety. The ability to bind fibrinogen is considered a potential pathogenicity trait that can lead to platelet aggregation, serious medical complications, and in some instances, death. Here we examined strains from species frequently used as probiotics for their ability to bind human fibrinogen. Only one strain (CCUG 47825), a Lactobacillus salivarius isolate from a case of septicaemia, was found to strongly adhere to fibrinogen. Furthermore, this strain was found to aggregate human platelets at a level comparable to the human pathogen Staphylococcus aureus. By sequencing the genome of CCUG 47825, we were able to identify candidate genes responsible for fibrinogen binding. Complementing the genetic analysis with traditional molecular microbiological techniques enabled the identification of the novel fibrinogen receptor, CCUG_2371. Although only strain CCUG 47825 bound fibrinogen under laboratory conditions, homologues of the novel fibrinogen binding gene CCUG_2371 are widespread among L. salivarius strains, maintaining their potential to bind fibrinogen if expressed. We highlight the fact that without a full genetic analysis of strains for human consumption, potential pathogenicity traits may go undetected. © 2012 Blackwell Publishing Ltd.

Study of Staphylococcus aureus N315 Pathogenic Genes by Text Mining and Enrichment Analysis of Pathways and Operons.

PubMed

Yang, Chun-Feng; Gou, Wei-Hui; Dai, Xin-Lun; Li, Yu-Mei

2018-06-01

Staphylococcus aureus (S. aureus) is a versatile pathogen found in many environments and can cause nosocomial infections in the community and hospitals. S. aureus infection is an increasingly serious threat to global public health that requires action across many government bodies, medical and health sectors, and scientific research institutions. In the present study, S. aureus N315 genes that have been shown in the literature to be pathogenic were extracted using a bibliometric method for functional enrichment analysis of pathways and operons to statistically discover novel pathogenic genes associated with S. aureus N315. A total of 383 pathogenic genes were mined from the literature using bibliometrics, and subsequently a few new pathogenic genes of S. aureus N315 were identified by functional enrichment analysis of pathways and operons. The discovery of these novel S. aureus N315 pathogenic genes is of great significance to treat S. aureus induced diseases and identify potential diagnostic markers, thus providing theoretical fundamentals for epidemiological prevention.

A human pathogenic bacterial infection model using the two-spotted cricket, Gryllus bimaculatus.

PubMed

Kochi, Yuto; Miyashita, Atsushi; Tsuchiya, Kohsuke; Mitsuyama, Masao; Sekimizu, Kazuhisa; Kaito, Chikara

2016-08-01

Invertebrate animal species that can withstand temperatures as high as 37°C, the human body temperature, are limited. In the present study, we utilized the two-spotted cricket, Gryllus bimaculatus, which lives in tropical and subtropical regions, as an animal model of human pathogenic bacterial infection. Injection of Pseudomonas aeruginosa or Staphylococcus aureus into the hemolymph killed crickets. Injected P. aeruginosa or S. aureus proliferated in the hemolymph until the cricket died. The ability of these pathogenic bacteria to kill the crickets was blocked by the administration of antibiotics. S. aureus gene-knockout mutants of virulence factors, including cvfA, agr and srtA, exhibited decreased killing ability compared with the parent strain. The dose at which 50% of crickets were killed by P. aeruginosa or S. aureus was not decreased at 37°C compared with that at 27°C. Injection of Listeria monocytogenes, which upregulates toxin expression at 37°C, killed crickets, and the dose at which 50% of crickets were killed was decreased at 37°C compared with that at 27°C. These findings suggest that the two-spotted cricket is a useful model animal for evaluating the virulence properties of various human pathogenic bacteria at variable temperature including 37°C. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Microbiology and foodborne pathogens in honey.

PubMed

Grabowski, N T; Klein, G

2017-06-13

Honey has been considered a relatively safe foodstuff due to its compositional properties, with infant botulism caused by Clostridium botulinum being the most prominent health risk associated with it. Our review is focused on the honey microflora along the food chain and evaluates the pathogenic potential of those microorganisms found in honey. This product may contain a great variety of bacteria and, particularly, fungi that eventually entered the food chain at an early stage (e.g., via pollen). For many of these microorganisms, opportunistic infections in humans have been recorded (e.g., infections by Staphylococcus spp., Citrobacter spp., Escherichia coli, Hafnia alvei, Aspergillus spp., Fusarium spp., Trichoderma spp., Chaetomium spp.), although direct infections via honey were not registered.

Characterization of multiple antibiotic resistance of culturable microorganisms and metagenomic analysis of total microbial diversity of marine fish sold in retail shops in Mumbai, India.

PubMed

Naik, Onkar A; Shashidhar, Ravindranath; Rath, Devashish; Bandekar, Jayant R; Rath, Archana

2018-03-01

Marine fish species were analyzed for culturable and total metagenomic microbial diversity, antibiotic resistance (AR) pattern, and horizontal gene transfer in culturable microorganisms. We observed a high AR microbial load of 3 to 4 log CFU g -1 . Many fish pathogens like Providencia, Staphylococcus, Klebsiella pneumoniae, Enterobacter, Vagococcus, and Aeromonas veronii were isolated. Photobacterium and Vibrio were two major fish and human pathogens which were identified in the fish metagenome. Other pathogens that were identified were Shewanella, Acinetobacter, Psychrobacter, and Flavobacterium. Most of these pathogens were resistant to multiple antibiotics such as erythromycin, kanamycin, neomycin, streptomycin, penicillin, cefotaxime, bacitracin, rifampicin, trimethoprim, ciprofloxacin, and doxycycline with a high multiple antibiotic resistance index of 0.54-0.77. The fish microflora showed high prevalence of AR genes like bla TEM , Class I integron, tetA, aph(3')-IIIa, ermB, aadA, and sul1. Nineteen of 26 AR isolates harbored Class I integrons showing high co-resistance to trimethoprim, kanamycin, doxycycline, and cefotaxime. Mobile R-plasmids from 6 of the 12 AR pathogens were transferred to recipient E. coli after conjugation. The transconjugants harbored the same R-plasmid carrying bla CTX-M , dfr1, tetA, bla TEM , and cat genes. This study confirms that fish is a potential carrier of AR pathogens which can enter the human gut via food chain. To the best of our knowledge, this is the first study in the Indian subcontinent reporting a direct evidence of spread of AR pathogens to humans from specific marine fish consumption.

Design and fabrication of an electrochemical aptasensor using Au nanoparticles/carbon nanoparticles/cellulose nanofibers nanocomposite for rapid and sensitive detection of Staphylococcus aureus.

PubMed

Ranjbar, Saba; Shahrokhian, Saeed

2018-04-27

Since that pathogenic bacteria are major threats to human health, this paper describes the fabrication of an effective and durable sensing platform based on gold nanoparticles/carbon nanoparticles/cellulose nanofibers nanocomposite (AuNPs/CNPs/CNFs) at the surface of glassy carbon electrode for sensitive and selective detection of Staphylococcus aureus (S. aureus). The AuNPs/CNPs/CNFs nanocomposite with the high surface area, excellent conductivity, and good biocompatibility was used for self-assembled of the thiolated specific S. aureus aptamer as a sensing element. The surface morphology of AuNPs/CNPs/CNFs nanocomposite was characterized with field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), dynamic light scattering (DLS) and ultraviolet-visible (UV-Vis) spectrophotometric methods. Each aptasensor modification step was monitored with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. The fabricated aptasensor exhibited a wide linear dynamic range (1.2 × 10 1 to 1.2 × 10 8 ) CFU mL -1 with a LOD of 1 CFU mL -1 and was be capable to accurate detection and determination of Staphylococcus aureus in human blood serum as a clinical sample with a complex matrix. Copyright © 2018 Elsevier B.V. All rights reserved.

Is the Colonisation of Staphylococcus aureus in Pets Associated with Their Close Contact with Owners?

PubMed Central

Bierowiec, Karolina; Płoneczka-Janeczko, Katarzyna; Rypuła, Krzysztof

2016-01-01

In human beings and animals, staphylococci constitute part of the normal microbial population. Staphylococcus aureus could be classified as an opportunistic pathogen because the bacteria are noted in clinically healthy individuals, but when the immune system becomes compromised, they can also cause a wide range of infections. The objective of this study was to test the hypothesis that cats who are in close contact with their owners are at the greatest risk of being colonised with S. aureus. Two groups of cats were investigated: single, pet (domestic) cats that do not have outdoor access; and a local population of feral cats living in urban areas. The prevalence of S. aureus in domestic cats was 19.17%, while it’s prevalence in the feral cat population was only 8.3%; which was statistically significant. Analysis of antibiotic resistance, at the genotypic as well as phenotypic level, showed that S. aureus isolates from pet cats were more likely to harbour antibiotic resistant determinants. The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in households was 10.21%, while in feral cats it was only 1.4%. In conclusion, this study has revealed a correlation between close contact with humans and a higher risk of the cats being colonised with S. aureus and harbouring the antibiotic resistant determinants. PMID:27227897

Quantification and risks associated with bacterial aerosols near domestic greywater-treatment systems.

PubMed

Benami, Maya; Busgang, Allison; Gillor, Osnat; Gross, Amit

2016-08-15

Greywater (GW) reuse can alleviate water stress by lowering freshwater consumption. However, GW contains pathogens that may compromise public health. During the GW-treatment process, bioaerosols can be produced and may be hazardous to human health if inhaled, ingested, or come in contact with skin. Using air-particle monitoring, BioSampler®, and settle plates we sampled bioaerosols emitted from recirculating vertical flow constructed wetlands (RVFCW) - a domestic GW-treatment system. An array of pathogens and indicators were monitored using settle plates and by culturing the BioSampler® liquid. Further enumeration of viable pathogens in the BioSampler® liquid utilized a newer method combining the benefits of enrichment with molecular detection (MPN-qPCR). Additionally, quantitative microbial risk assessment (QMRA) was applied to assess risks of infection from a representative skin pathogen, Staphylococcus aureus. According to the settle-plate technique, low amounts (0-9.7×10(4)CFUm(-2)h(-1)) of heterotrophic bacteria, Staphylococcus spp., Pseudomonas spp., Klebsiella pneumoniae, Enterococcus spp., and Escherichia coli were found to aerosolize up to 1m away from the GW systems. At the 5m distance amounts of these bacteria were not statistically different (p>0.05) from background concentrations tested over 50m away from the systems. Using the BioSampler®, no bacteria were detected before enrichment of the GW-aerosols. However, after enrichment, using an MPN-qPCR technique, viable indicators and pathogens were occasionally detected. Consequently, the QMRA results were below the critical disability-adjusted life year (DALY) safety limits, a measure of overall disease burden, for S. aureus under the tested exposure scenarios. Our study suggests that health risks from aerosolizing pathogens near RVFCW GW-treatment systems are likely low. This study also emphasizes the growing need for standardization of bioaerosol-evaluation techniques to provide more accurate quantification of small amounts of viable, aerosolized bacterial pathogens. Copyright © 2016 Elsevier B.V. All rights reserved.

In vitro characterization of the antivirulence target of Gram-positive pathogens, peptidoglycan O-acetyltransferase A (OatA)

DOE PAGES

Sychantha, David; Jones, Carys S.; Little, Dustin J.; ...

2017-10-27

The O-acetylation of the essential cell wall polymer peptidoglycan occurs in most Gram-positive bacterial pathogens, including species of Staphylococcus, Streptococcus and Enterococcus. This modification to peptidoglycan protects these pathogens from the lytic action of the lysozymes of innate immunity systems and, as such, is recognized as a virulence factor. The key enzyme involved, peptidoglycan O-acetyltransferase A (OatA) represents a particular challenge to biochemical study since it is a membrane associated protein whose substrate is the insoluble peptidoglycan cell wall polymer. OatA is predicted to be bimodular, being comprised of an N-terminal integral membrane domain linked to a C-terminal extracytoplasmic domain.more » We present herein the first biochemical and kinetic characterization of the C-terminal catalytic domain of OatA from two important human pathogens, Staphylococcus aureus and Streptococcus pneumoniae. Using both pseudosubstrates and novel biosynthetically-prepared peptidoglycan polymers, we characterized distinct substrate specificities for the two enzymes. In addition, the high resolution crystal structure of the C-terminal domain reveals an SGNH/GDSL-like hydrolase fold with a catalytic triad of amino acids but with a non-canonical oxyanion hole structure. Site-specific replacements confirmed the identity of the catalytic and oxyanion hole residues. A model is presented for the O-acetylation of peptidoglycan whereby the translocation of acetyl groups from a cytoplasmic source across the cytoplasmic membrane is catalyzed by the N-terminal domain of OatA for their transfer to peptidoglycan by its C-terminal domain. This study on the structure-function relationship of OatA provides a molecular and mechanistic understanding of this bacterial resistance mechanism opening the prospect for novel chemotherapeutic exploration to enhance innate immunity protection against Gram-positive pathogens.« less

In vitro characterization of the antivirulence target of Gram-positive pathogens, peptidoglycan O-acetyltransferase A (OatA)

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

Sychantha, David; Jones, Carys S.; Little, Dustin J.

The O-acetylation of the essential cell wall polymer peptidoglycan occurs in most Gram-positive bacterial pathogens, including species of Staphylococcus, Streptococcus and Enterococcus. This modification to peptidoglycan protects these pathogens from the lytic action of the lysozymes of innate immunity systems and, as such, is recognized as a virulence factor. The key enzyme involved, peptidoglycan O-acetyltransferase A (OatA) represents a particular challenge to biochemical study since it is a membrane associated protein whose substrate is the insoluble peptidoglycan cell wall polymer. OatA is predicted to be bimodular, being comprised of an N-terminal integral membrane domain linked to a C-terminal extracytoplasmic domain.more » We present herein the first biochemical and kinetic characterization of the C-terminal catalytic domain of OatA from two important human pathogens, Staphylococcus aureus and Streptococcus pneumoniae. Using both pseudosubstrates and novel biosynthetically-prepared peptidoglycan polymers, we characterized distinct substrate specificities for the two enzymes. In addition, the high resolution crystal structure of the C-terminal domain reveals an SGNH/GDSL-like hydrolase fold with a catalytic triad of amino acids but with a non-canonical oxyanion hole structure. Site-specific replacements confirmed the identity of the catalytic and oxyanion hole residues. A model is presented for the O-acetylation of peptidoglycan whereby the translocation of acetyl groups from a cytoplasmic source across the cytoplasmic membrane is catalyzed by the N-terminal domain of OatA for their transfer to peptidoglycan by its C-terminal domain. This study on the structure-function relationship of OatA provides a molecular and mechanistic understanding of this bacterial resistance mechanism opening the prospect for novel chemotherapeutic exploration to enhance innate immunity protection against Gram-positive pathogens.« less

Protective Effect of Vaginal Lactobacillus paracasei CRL 1289 against Urogenital Infection Produced by Staphylococcus aureus in a Mouse Animal Model

PubMed Central

Zárate, Gabriela; Santos, Viviana; Nader-Macias, María Elena

2007-01-01

Urogenital infections of bacterial origin have a high incidence among the world female population at reproductive age. Lactobacilli, the predominant microorganisms of the healthy vaginal microbiota, have shown a protective effect against the colonization and overgrowth of urogenital pathogens that increased the interest for including them into probiotics products assigned to restore the urogenital balance. In the present work, we determined in a mouse animal model the capability of Lactobacillus paracasei CRL 1289, a human vaginal strain with probiotic properties, to prevent the vaginal colonization of a uropathogenic strain of Staphylococcus aureus. Six-week-old female BALB/c mice, synchronized in their estral cycle, were intravaginally inoculated with two doses of 109 lactobacilli before challenging them with a single dose of 105 or 107 CFU of S. aureus. The vaginal colonization of both microorganisms and the effect on the vaginal structure were determined at 2, 5, and 7 days after pathogen inoculation. Control mice and those challenged only with the pathogen showed an insignificant lactobacilli population, whereas 105 lactobacilli/mL of vaginal homogenate were recovered at 2 days after challenge from the L. paracasei CRL 1289 and the probiotic + pathogen groups, decreasing this number on the following days. The treatment with L. paracasei CRL 1289 decreased significantly the number of staphylococci recovered at 2 and 5 days when mice were challenged only with 105 CFU of pathogen. The inoculation of S. aureus produced a remarkable inflammatory response and structural alterations in the vaginal mucosa that decreases in a significant manner when the mice were protected with L. paracasei CRL 1289. The results obtained suggest that this particular Lactobacillus strain could prevent the onset of urogenital infections by interfering with the epithelial colonization by uropathogenic S. aureus. PMID:17485818

In vitro characterization of the antivirulence target of Gram-positive pathogens, peptidoglycan O-acetyltransferase A (OatA)

PubMed Central

Sychantha, David; Jones, Carys S.; Little, Dustin J.; Howell, P. Lynne

2017-01-01

The O-acetylation of the essential cell wall polymer peptidoglycan occurs in most Gram-positive bacterial pathogens, including species of Staphylococcus, Streptococcus and Enterococcus. This modification to peptidoglycan protects these pathogens from the lytic action of the lysozymes of innate immunity systems and, as such, is recognized as a virulence factor. The key enzyme involved, peptidoglycan O-acetyltransferase A (OatA) represents a particular challenge to biochemical study since it is a membrane associated protein whose substrate is the insoluble peptidoglycan cell wall polymer. OatA is predicted to be bimodular, being comprised of an N-terminal integral membrane domain linked to a C-terminal extracytoplasmic domain. We present herein the first biochemical and kinetic characterization of the C-terminal catalytic domain of OatA from two important human pathogens, Staphylococcus aureus and Streptococcus pneumoniae. Using both pseudosubstrates and novel biosynthetically-prepared peptidoglycan polymers, we characterized distinct substrate specificities for the two enzymes. In addition, the high resolution crystal structure of the C-terminal domain reveals an SGNH/GDSL-like hydrolase fold with a catalytic triad of amino acids but with a non-canonical oxyanion hole structure. Site-specific replacements confirmed the identity of the catalytic and oxyanion hole residues. A model is presented for the O-acetylation of peptidoglycan whereby the translocation of acetyl groups from a cytoplasmic source across the cytoplasmic membrane is catalyzed by the N-terminal domain of OatA for their transfer to peptidoglycan by its C-terminal domain. This study on the structure-function relationship of OatA provides a molecular and mechanistic understanding of this bacterial resistance mechanism opening the prospect for novel chemotherapeutic exploration to enhance innate immunity protection against Gram-positive pathogens. PMID:29077761

Cross-Talk between Staphylococcus aureus and Other Staphylococcal Species via the agr Quorum Sensing System

PubMed Central

Canovas, Jaime; Baldry, Mara; Bojer, Martin S.; Andersen, Paal S.; Gless, Bengt H.; Grzeskowiak, Piotr K.; Stegger, Marc; Damborg, Peter; Olsen, Christian A.; Ingmer, Hanne

2016-01-01

Staphylococci are associated with both humans and animals. While most are non-pathogenic colonizers, Staphylococcus aureus is an opportunistic pathogen capable of causing severe infections. S. aureus virulence is controlled by the agr quorum sensing system responding to secreted auto-inducing peptides (AIPs) sensed by AgrC, a two component histidine kinase. agr loci are found also in other staphylococcal species and for Staphylococcus epidermidis, the encoded AIP represses expression of agr regulated virulence genes in S. aureus. In this study we aimed to better understand the interaction between staphylococci and S. aureus, and show that this interaction may eventually lead to the identification of new anti-virulence candidates to target S. aureus infections. Here we show that culture supernatants of 37 out of 52 staphylococcal isolates representing 17 different species inhibit S. aureus agr. The dog pathogen, Staphylococcus schleiferi, expressed the most potent inhibitory activity and was active against all four agr classes found in S. aureus. By employing a S. aureus strain encoding a constitutively active AIP receptor we show that the activity is mediated via agr. Subsequent cloning and heterologous expression of the S. schleiferi AIP in S. aureus demonstrated that this molecule was likely responsible for the inhibitory activity, and further proof was provided when pure synthetic S. schleiferi AIP was able to completely abolish agr induction of an S. aureus reporter strain. To assess impact on S. aureus virulence, we co-inoculated S. aureus and S. schleiferi in vivo in the Galleria mellonella wax moth larva, and found that expression of key S. aureus virulence factors was abrogated. Our data show that the S. aureus agr locus is highly responsive to other staphylococcal species suggesting that agr is an inter-species communication system. Based on these results we speculate that interactions between S. aureus and other colonizing staphylococci will significantly influence the ability of S. aureus to cause infection, and we propose that other staphylococci are potential sources of compounds that can be applied as anti-virulence therapy for combating S. aureus infections. PMID:27877157

Diversity of Bacterial Communities of Fitness Center Surfaces in a U.S. Metropolitan Area

PubMed Central

Mukherjee, Nabanita; Dowd, Scot E.; Wise, Andy; Kedia, Sapna; Vohra, Varun; Banerjee, Pratik

2014-01-01

Public fitness centers and exercise facilities have been implicated as possible sources for transmitting community-acquired bacterial infections. However, the overall diversity of the bacterial community residing on the surfaces in these indoor environments is still unknown. In this study, we investigated the overall bacterial ecology of selected fitness centers in a metropolitan area (Memphis, TN, USA) utilizing culture-independent pyrosequencing of the 16S rRNA genes. Samples were collected from the skin-contact surfaces (e.g., exercise instruments, floor mats, handrails, etc.) within fitness centers. Taxonomical composition revealed the abundance of Firmicutes phyla, followed by Proteobacter and Actinobacteria, with a total of 17 bacterial families and 25 bacterial genera. Most of these bacterial genera are of human and environmental origin (including, air, dust, soil, and water). Additionally, we found the presence of some pathogenic or potential pathogenic bacterial genera including Salmonella, Staphylococcus, Klebsiella, and Micrococcus. Staphylococcus was found to be the most prevalent genus. Presence of viable forms of these pathogens elevates risk of exposure of any susceptible individuals. Several factors (including personal hygiene, surface cleaning and disinfection schedules of the facilities) may be the reasons for the rich bacterial diversity found in this study. The current finding underscores the need to increase public awareness on the importance of personal hygiene and sanitation for public gym users. PMID:25479039

Application of bacteriophages in post-harvest control of human pathogenic and food spoiling bacteria.

PubMed

Pérez Pulido, Rubén; Grande Burgos, Maria José; Gálvez, Antonio; Lucas López, Rosario

2016-10-01

Bacteriophages have attracted great attention for application in food biopreservation. Lytic bacteriophages specific for human pathogenic bacteria can be isolated from natural sources such as animal feces or industrial wastes where the target bacteria inhabit. Lytic bacteriophages have been tested in different food systems for inactivation of main food-borne pathogens including Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O157:H7, Salmonella enterica, Shigella spp., Campylobacter jejuni and Cronobacter sakazkii, and also for control of spoilage bacteria. Application of lytic bacteriophages could selectively control host populations of concern without interfering with the remaining food microbiota. Bacteriophages could also be applied for inactivation of bacteria attached to food contact surfaces or grown as biofilms. Bacteriophages may receive a generally recognized as safe status based on their lack of toxicity and other detrimental effects to human health. Phage preparations specific for L. monocytogenes, E. coli O157:H7 and S. enterica serotypes have been commercialized and approved for application in foods or as part of surface decontamination protocols. Phage endolysins have a broader host specificity compared to lytic bacteriophages. Cloned endolysins could be used as natural preservatives, singly or in combination with other antimicrobials such as bacteriocins.

Loofah sponges as reservoirs and vehicles in the transmission of potentially pathogenic bacterial species to human skin.

PubMed Central

Bottone, E J; Perez, A A; Oeser, J L

1994-01-01

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. Images PMID:8150959

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.

Biosynthesis of Cu, ZVI, and Ag nanoparticles using Dodonaea viscosa extract for antibacterial activity against human pathogens

NASA Astrophysics Data System (ADS)

Kiruba Daniel, S. C. G.; Vinothini, G.; Subramanian, N.; Nehru, K.; Sivakumar, M.

2013-01-01

Biosynthesis of copper, zero-valent iron (ZVI), and silver nanoparticles using leaf extract of Dodonaea viscosa has been investigated in this report. There are no additional surfactants/polymers used as capping or reducing agents for these syntheses. The synthesized nanoparticles were characterized by UV-Vis spectroscopy, X-ray diffraction, atomic force microscopy, and high-resolution transmission electron microscopy. The phase analysis was performed using selected area electron diffraction. The pH dependence of surface plasmon resonance and subsequent size variation has been determined. The synthesized nanoparticles showed spherical morphology and the average size of 29, 27, and 16 nm for Cu, ZVI, and Ag nanoparticles, respectively. Finally, biosynthesized Cu, ZVI, and Ag nanoparticles were tested against human pathogens viz. Gram-negative Escherichia coli, Klebsiella pneumonia, Pseudomonas fluorescens and Gram-positive Staphylococcus aureus and Bacillus subtilis, and showed good antimicrobial activity.

Pulsed-field gel electrophoresis typing of Staphylococcus aureus isolates

USDA-ARS?s Scientific Manuscript database

Pulsed-field gel electrophoresis (PFGE) is the most applied and effective genetic typing method for epidemiological studies and investigation of foodborne outbreaks caused by different pathogens, including Staphylococcus aureus. The technique relies on analysis of large DNA fragments generated by th...

Staphylococcus aureus Shifts toward Commensalism in Response to Corynebacterium Species

PubMed Central

Ramsey, Matthew M.; Freire, Marcelo O.; Gabrilska, Rebecca A.; Rumbaugh, Kendra P.; Lemon, Katherine P.

2016-01-01

Staphylococcus aureus–human interactions result in a continuum of outcomes from commensalism to pathogenesis. S. aureus is a clinically important pathogen that asymptomatically colonizes ~25% of humans as a member of the nostril and skin microbiota, where it resides with other bacteria including commensal Corynebacterium species. Commensal Corynebacterium spp. are also positively correlated with S. aureus in chronic polymicrobial diabetic foot infections, distinct from acute monomicrobial S. aureus infections. Recent work by our lab and others indicates that microbe–microbe interactions between S. aureus and human skin/nasal commensals, including Corynebacterium species, affect S. aureus behavior and fitness. Thus, we hypothesized that S. aureus interactions with Corynebacterium spp. diminish S. aureus virulence. We tested this by assaying for changes in S. aureus gene expression during in vitro mono- versus coculture with Corynebacterium striatum, a common skin and nasal commensal. We observed a broad shift in S. aureus gene transcription during in vitro growth with C. striatum, including increased transcription of genes known to exhibit increased expression during human nasal colonization and decreased transcription of virulence genes. S. aureus uses several regulatory pathways to transition between commensal and pathogenic states. One of these, the quorum signal accessory gene regulator (agr) system, was strongly inhibited in response to Corynebacterium spp. Phenotypically, S. aureus exposed to C. striatum exhibited increased adhesion to epithelial cells, reflecting a commensal state, and decreased hemolysin activity, reflecting an attenuation of virulence. Consistent with this, S. aureus displayed diminished fitness in experimental in vivo coinfection with C. striatum when compared to monoinfection. These data support a model in which S. aureus shifts from virulence toward a commensal state when exposed to commensal Corynebacterium species. PMID:27582729

Antimicrobial peptides effectively kill a broad spectrum of Listeria monocytogenes and Staphylococcus aureus strains independently of origin, sub-type, or virulence factor expression.

PubMed

Gottlieb, Caroline Trebbien; Thomsen, Line Elnif; Ingmer, Hanne; Mygind, Per Holse; Kristensen, Hans-Henrik; Gram, Lone

2008-11-26

Host defense peptides (HDPs), or antimicrobial peptides (AMPs), are important components of the innate immune system that bacterial pathogens must overcome to establish an infection and HDPs have been suggested as novel antimicrobial therapeutics in treatment of infectious diseases. Hence it is important to determine the natural variation in susceptibility to HDPs to ensure a successful use in clinical treatment regimes. Strains of two human bacterial pathogens, Listeria monocytogenes and Staphylococcus aureus, were selected to cover a wide range of origin, sub-type, and phenotypic behavior. Strains within each species were equally sensitive to HDPs and oxidative stress representing important components of the innate immune defense system. Four non-human peptides (protamine, plectasin, novicidin, and novispirin G10) were similar in activity profile (MIC value spectrum) to the human beta-defensin 3 (HBD-3). All strains were inhibited by concentrations of hydrogen peroxide between 0.1% - 1.0%. Sub-selections of both species differed in expression of several virulence-related factors and in their ability to survive in human whole blood and kill the nematode virulence model Caenorhabditis elegans. For L. monocytogenes, proliferation in whole blood was paralleled by high invasion in Caco-2 cells and fast killing of C. elegans, however, no such pattern in phenotypic behavior was observed for S. aureus and none of the phenotypic differences were correlated to sensitivity to HDPs. Strains of L. monocytogenes and S. aureus were within each species equally sensitive to a range of HDPs despite variations in subtype, origin, and phenotypic behavior. Our results suggest that therapeutic use of HDPs will not be hampered by occurrence of naturally tolerant strains of the two species investigated in the present study.

Lysionotin attenuates Staphylococcus aureus pathogenicity by inhibiting α-toxin expression.

PubMed

Teng, Zihao; Shi, Dongxue; Liu, Huanyu; Shen, Ziying; Zha, Yonghong; Li, Wenhua; Deng, Xuming; Wang, Jianfeng

2017-09-01

α-Toxin, one of the best known pore-forming proteins produced by Staphylococcus aureus (S. aureus), is a critical virulence factor in multiple infections. The necessity of α-toxin for S. aureus pathogenicity suggests that this toxin is an important target for the development of a potential treatment strategy. In this study, we showed that lysionotin, a natural compound, can inhibit the hemolytic activity of culture supernatants by S. aureus by reducing α-toxin expression. Using real-time PCR analysis, we showed that transcription of hla (the gene encoding α-toxin) and agr (the locus regulating hla) was significantly inhibited by lysionotin. Lactate dehydrogenase and live/dead assays indicated that lysionotin effectively protected human alveolar epithelial cells against S. aureus, and in vivo studies also demonstrated that lysionotin can protect mice from pneumonia caused by S. aureus. These findings suggest that lysionotin is an efficient inhibitor of α-toxin expression and shows significant protection against S. aureus in vitro and in vivo. This study supports a potential strategy for the treatment of S. aureus infection by inhibiting the expression of virulence factors and indicates that lysionotin may be a potential treatment for S. aureus pneumonia.

Intracellular Survival of Staphylococcus aureus in Endothelial Cells: A Matter of Growth or Persistence

PubMed Central

Rollin, Guillaume; Tan, Xin; Tros, Fabiola; Dupuis, Marion; Nassif, Xavier; Charbit, Alain; Coureuil, Mathieu

2017-01-01

The Gram-positive human pathogen Staphylococcus aureus is a leading cause of severe bacterial infections. Recent studies have shown that various cell types could readily internalize S. aureus and infected cells have been proposed to serve as vehicle for the systemic dissemination of the pathogen. Here we focused on the intracellular behavior of the Community-Associated Methicillin-Resistant S. aureus strain USA300. Supporting earlier observations, we found that wild-type S. aureus strain USA300 persisted for longer period within endothelial cells than within macrophages and that a mutant displaying the small colony variant phenotype (ΔhemDBL) had increased intracellular persistence. Time-lapse microscopy revealed that initial persistence of wild-type bacteria in endothelial cells corresponded to distinct single cell events, ranging from active intracellular bacterial proliferation, leading to cell lysis, to non-replicating bacterial persistence even 1 week after infection. In sharp contrast, ΔhemDBL mutant bacteria were essentially non-replicating up to 10 days after infection. These findings suggest that internalization of S. aureus in endothelial cells triggers its persistence and support the notion that endothelial cells might constitute an intracellular persistence niche responsible for reported relapse of infection after antibiotic therapy. PMID:28769913

Role of quorum sensing in bacterial infections

PubMed Central

Castillo-Juárez, Israel; Maeda, Toshinari; Mandujano-Tinoco, Edna Ayerim; Tomás, María; Pérez-Eretza, Berenice; García-Contreras, Silvia Julieta; Wood, Thomas K; García-Contreras, Rodolfo

2015-01-01

Quorum sensing (QS) is cell communication that is widely used by bacterial pathogens to coordinate the expression of several collective traits, including the production of multiple virulence factors, biofilm formation, and swarming motility once a population threshold is reached. Several lines of evidence indicate that QS enhances virulence of bacterial pathogens in animal models as well as in human infections; however, its relative importance for bacterial pathogenesis is still incomplete. In this review, we discuss the present evidence from in vitro and in vivo experiments in animal models, as well as from clinical studies, that link QS systems with human infections. We focus on two major QS bacterial models, the opportunistic Gram negative bacteria Pseudomonas aeruginosa and the Gram positive Staphylococcus aureus, which are also two of the main agents responsible of nosocomial and wound infections. In addition, QS communication systems in other bacterial, eukaryotic pathogens, and even immune and cancer cells are also reviewed, and finally, the new approaches proposed to combat bacterial infections by the attenuation of their QS communication systems and virulence are also discussed. PMID:26244150

Linezolid-resistant mucoid Staphylococcus haemolyticus from a tertiary-care centre in Delhi.

PubMed

Matlani, M; Shende, T; Bhandari, V; Dawar, R; Sardana, R; Gaind, R

2016-05-01

We report an unusual morphological mucoid variant of Staphylococcus haemolyticus associated with linezolid resistance from a patient with sepsis. Linezolid resistance and mucoid character together made this pathogen difficult to treat. To our knowledge this is the first such report.

Characterization of Staphylococcus aureus strains involved in human and bovine mastitis.

PubMed

Delgado, Susana; García, Pilar; Fernández, Leonides; Jiménez, Esther; Rodríguez-Baños, Mercedes; del Campo, Rosa; Rodríguez, Juan M

2011-07-01

Staphylococcus aureus is one of the main etiological agents of mastitis in different mammalian species. At present, it is unknown whether strains isolated from human mastitis cases share phenotypic properties and genetic background with those obtained from animal mastitis cases. Therefore, the objective of this study was to characterize S. aureus strains isolated from women with lactational mastitis and to compare them with the strains responsible for bovine mastitis and noninfectious strains. All the strains were genotyped by both pulsed field gel electrophoresis and multilocus sequence typing and submitted to a characterization scheme that included diverse assays related to pathogenic potential and antibiotic resistance. Apart from siderophore production, no significant association was observed between the strains from bovine and human mastitis. Statistical differences between human- and bovine-mastitis-associated strains were detected for some traits and virulence determinants, such as the presence of prophages and cna and hlb genes, which were more frequently found within the bovine group. On the contrary, resistance to penicillin was significantly higher among strains isolated from human lactational mastitis, probably related to the common presence of the blaZ gene. A high genetic diversity was found among the strains involved in mastitis in breastfeeding women. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Human SAP is a novel peptidoglycan recognition protein that induces complement- independent phagocytosis of Staphylococcus aureus

PubMed Central

An, Jang-Hyun; Kurokawa, Kenji; Jung, Dong-Jun; Kim, Min-Jung; Kim, Chan-Hee; Fujimoto, Yukari; Fukase, Koichi; Coggeshall, K. Mark; Lee, Bok Luel

2014-01-01

The human pathogen Staphylococcus aureus is responsible for many community-acquired and hospital-associated infections and is associated with high mortality. Concern over the emergence of multidrug-resistant strains has renewed interest in the elucidation of host mechanisms that defend against S. aureus infection. We recently demonstrated that human serum mannose-binding lectin (MBL) binds to S. aureus wall teichoic acid (WTA), a cell wall glycopolymer, a discovery that prompted further screening to identify additional serum proteins that recognize S. aureus cell wall components. In this report, we incubated human serum with 10 different S. aureus mutants and determined that serum amyloid P component (SAP) bound specifically to a WTA-deficient S. aureus ΔtagO mutant, but not to tagO-complemented, WTA-expressing cells. Biochemical characterization revealed that SAP recognizes bacterial peptidoglycan as a ligand and that WTA inhibits this interaction. Although SAP binding to peptidoglycan was not observed to induce complement activation, SAP-bound ΔtagO cells were phagocytosed by human polymorphonuclear leukocytes in an Fcγ receptor-dependent manner. These results indicate that SAP functions as a host defense factor, similar to other peptidoglycan recognition proteins and nucleotide-binding oligomerization domain (NOD)-like receptors. PMID:23966633

Epidemiology, Clinical Characteristics, and Antimicrobial Susceptibility Profiles of Human Clinical Isolates of Staphylococcus intermedius Group.

PubMed

Yarbrough, Melanie L; Lainhart, William; Burnham, C A

2018-03-01

The veterinary pathogens in the Staphylococcus intermedius group (SIG) are increasingly recognized as causes of human infection. Shared features between SIG and Staphylococcus aureus may result in the misidentification of SIG in human clinical cultures. This study examined the clinical and microbiological characteristics of isolates recovered at a tertiary-care academic medical center. From 2013 to 2015, 81 SIG isolates were recovered from 62 patients. Patients were commonly ≥50 years old, diabetic, and/or immunocompromised. Documentation of dog exposure in the electronic medical record was not common. Of the 81 SIG isolates, common sites of isolation included 37 (46%) isolates from wound cultures and 17 (21%) isolates from respiratory specimens. Although less common, 10 (12%) bloodstream infections were documented in 7 unique patients. The majority of SIG (65%) isolates were obtained from polymicrobial cultures. In comparison to S. aureus isolates from the same time period, significant differences were noted in proportion of SIG isolates that were susceptible to doxycycline (74% versus 97%, respectively; P < 0.001), trimethoprim-sulfamethoxazole (65% versus 97%, respectively; P < 0.001), and ciprofloxacin (78% versus 59%, respectively; P < 0.01). Methicillin resistance (MR) was detected in 12 (15%) of 81 SIG isolates. All MR isolates detected by an oxacillin disk diffusion test would have been misclassified as methicillin susceptible using a cefoxitin disk diffusion test. Thus, SIG is recovered from human clinical specimens, and distinction of SIG from S. aureus is critical for the accurate characterization of MR status in these isolates. Copyright © 2018 American Society for Microbiology.

Antimicrobial therapy of selected diseases in turkeys, laying hens, and minor poultry species in Canada

PubMed Central

Agunos, Agnes; Carson, Carolee; Léger, Dave

2013-01-01

This paper identifies common poultry diseases requiring antimicrobial therapy, antimicrobials deemed efficacious to treat these diseases, and antimicrobial resistance (AMR) in these commodity-pathogen combinations, and describes current residue issues and minor use minor species (MUMS) guidelines. Veterinarians with turkey/layer expertise and diagnosticians were surveyed to determine the bacterial and protozoal diseases diagnosed in the last 5 years. Avian pathogenic Escherichia coli, Staphylococcus aureus, and Ornithobacterium rhinotracheale were the 3 most frequently diagnosed pathogens of turkeys. In layers, E. coli-peritonitis, and Clostridium perfringens/Eimeria spp. infections were the most common diagnoses. A literature review identified 32 antimicrobials as efficacious and/or recommended for treating these diseases. Surveillance and monitoring indicate the presence of enteric resistant organisms from some of these avian species (including resistance to antimicrobials of very high importance to human medicine). This paper highlights the need for surveillance of pathogen frequency, antimicrobial use (AMU), and AMR particularly in turkeys. PMID:24179239

Matrix-assisted laser desorption ionization time of flight mass spectrometry and diagnostic testing for prosthetic joint infection in the clinical microbiology laboratory.

PubMed

Peel, Trisha N; Cole, Nicolynn C; Dylla, Brenda L; Patel, Robin

2015-03-01

Identification of pathogen(s) associated with prosthetic joint infection (PJI) is critical for patient management. Historically, many laboratories have not routinely identified organisms such as coagulase-negative staphylococci to the species level. The advent of matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) has enhanced clinical laboratory capacity for accurate species-level identification. The aim of this study was to describe the species-level identification of microorganisms isolated from periprosthetic tissue and fluid specimens using MALDI-TOF MS alongside other rapid identification tests in a clinical microbiology laboratory. Results of rapid identification of bacteria isolated from periprosthetic joint fluid and/or tissue specimens were correlated with clinical findings at Mayo Clinic, Rochester, Minnesota, between May 2012 and May 2013. There were 178 PJI and 82 aseptic failure (AF) cases analyzed, yielding 770 organisms (median, 3/subject; range, 1-19/subject). MALDI-TOF MS was employed for the identification of 455 organisms (59%) in 197 subjects (123 PJIs and 74 AFs), with 89% identified to the species level using this technique. Gram-positive bacteria accounted for 68% and 93% of isolates in PJI and AF, respectively. However, the profile of species associated with infection compared to specimen contamination differed. Staphylococcus aureus and Staphylococcus caprae were always associated with infection, Staphylococcus epidermidis and Staphylococcus lugdunensis were equally likely to be a pathogen or a contaminant, whereas the other coagulase-negative staphylococci were more frequently contaminants. Most streptococcal and Corynebacterium isolates were pathogens. The likelihood that an organism was a pathogen or contaminant differed with the prosthetic joint location, particularly in the case of Propionibacterium acnes. MALDI-TOF MS is a valuable tool for the identification of bacteria isolated from patients with prosthetic joints, providing species-level identification that may inform culture interpretation of pathogens versus contaminants. Copyright © 2015 Elsevier Inc. All rights reserved.

Effect of Pneumococcal Vaccination on Nasopharyngeal Carriage of Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Staphylococcus aureus in Fijian Children

PubMed Central

Manning, Jayne; Russell, Fiona M.; Robins-Browne, Roy M.; Mulholland, E. Kim; Satzke, Catherine

2012-01-01

The 7-valent pneumococcal conjugate vaccine (PCV7) reduces carriage of vaccine type Streptococcus pneumoniae but leads to replacement by nonvaccine serotypes and may affect carriage of other respiratory pathogens. We investigated nasopharyngeal carriage of S. pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Staphylococcus aureus in Fijian infants participating in a pneumococcal vaccine trial using quantitative PCR. Vaccination did not affect pathogen carriage rates or densities, whereas significant differences between the two major ethnic groups were observed. PMID:22170924

The blow fly, Chrysomya megacephala, and the house fly, Musca domestica, as mechanical vectors of pathogenic bacteria in Northeast Thailand.

PubMed

Chaiwong, T; Srivoramas, T; Sueabsamran, P; Sukontason, K; Sanford, M R; Sukontason, K L

2014-06-01

The Oriental latrine fly, Chrysomya megacephala (Fabricius) (Diptera: Calliphoridae) and the house fly, Musca domestica L., (Diptera: Muscidae) are synanthropic flies which are adapted to live in close association with human habitations, thereby making them likely mechanical vectors of several pathogens to humans. There were two main aims of this study. The first aim was to determine the prevalence of these two fly species from five types of human habitations including: fresh-food markets, garbage piles, restaurants, school cafeterias and paddy fields, in the Muang Ubon Ratchathani and Warinchamrap districts of Ubon Ratchathani province of Northeast Thailand. Flies collection were conducted monthly from September 2010-October 2011 using a reconstructable funnel trap, containing 1 day-tainted beef offal as bait. A total of 7 750 flies (6 401 C. megacephala and 1 349 M.domestica) were collected. The second aim was to examine the potential of these flies to carry pathogenic bacteria. Bacteria were isolated from 994 individual flies collected using a sweep net (555 C. megacephala and 439 M. domestica). A total of 15 bacterial genera were isolated from the external surfaces, comprising ten genera of gram-negative bacteria and five gram-positive bacteria. The most common bacteria isolated from both species were coagulase-negative staphylococci, followed by Streptococcus group D non-enterococci. Human pathogenic enteric bacteria isolated were Salmonella sp., Shigella sp., Escherichia coli O157:H7, Salmonella typhi, Bacillus sp., and Enterococcus sp., of which S. typhi is the first report of isolation from these fly species. Other human pathogens included Staphylococcus aureus and Pseudomonas aeruginosa. Not only were the number of C. megacephala positive for bacteria significantly higher than for M. domestica, but they were also carrying ~11-12 times greater bacterial load than M. domestica. These data suggest that both fly species should be considered potential mechanical vectors of bacterial pathogens associated with human habitations year-round in this region of Northeast Thailand.

Innate Immune Signaling Activated by MDR Bacteria in the Airway

PubMed Central

Parker, Dane; Ahn, Danielle; Cohen, Taylor; Prince, Alice

2015-01-01

Health care-associated bacterial pneumonias due to multiple-drug resistant (MDR) pathogens are an important public health problem and are major causes of morbidity and mortality worldwide. In addition to antimicrobial resistance, these organisms have adapted to the milieu of the human airway and have acquired resistance to the innate immune clearance mechanisms that normally prevent pneumonia. Given the limited efficacy of antibiotics, bacterial clearance from the airway requires an effective immune response. Understanding how specific airway pathogens initiate and regulate innate immune signaling, and whether this response is excessive, leading to host-induced pathology may guide future immunomodulatory therapy. We will focus on three of the most important causes of health care-associated pneumonia, Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae, and review the mechanisms through which an inappropriate or damaging innate immune response is stimulated, as well as describe how airway pathogens cause persistent infection by evading immune activation. PMID:26582515

Interplay Between Antibiotic Resistance and Virulence During Disease Promoted by Multidrug-Resistant Bacteria

PubMed Central

Geisinger, Edward

2017-01-01

Abstract Diseases caused by antibiotic-resistant bacteria in hospitals are the outcome of complex relationships between several dynamic factors, including bacterial pathogenicity, the fitness costs of resistance in the human host, and selective forces resulting from interventions such as antibiotic therapy. The emergence and fate of mutations that drive antibiotic resistance are governed by these interactions. In this review, we will examine how different forms of antibiotic resistance modulate bacterial fitness and virulence potential, thus influencing the ability of pathogens to evolve in the context of nosocomial infections. We will focus on 3 important multidrug-resistant pathogens that are notoriously problematic in hospitals: Pseudomonas aeruginosa, Acinetobacter baumannii, and Staphylococcus aureus. An understanding of how antibiotic resistance mutations shape the pathobiology of multidrug-resistant infections has the potential to drive novel strategies that can control the development and spread of drug resistance. PMID:28375515

Multidrug-resistant opportunistic pathogens challenging veterinary infection control.

PubMed

Walther, Birgit; Tedin, Karsten; Lübke-Becker, Antina

2017-02-01

Although the problems associated with healthcare-associated infections (HAI) and the emergence of zoonotic and multidrug-resistant pathogens in companion animal (dogs, cats and horses) medicine have been well-known for decades, current progress with respect to practical implementation of infection control programs in veterinary clinics has been limited. Clinical outbreak events reported for methicillin-resistant Staphylooccus aureus (MRSA) and Staphylococcus pseudintermedius (MRSP), extended spectrum beta-lactamase (ESBL)-producing Escherichia coli and multidrug-resistant (MDR) Salmonella Serovars indicate the necessity of infection control strategies for protecting animal patients at risk as well as veterinary personnel. The close bond between humans and their companion animals provides opportunities for exchange of microorganisms, including MDR pathogens. This particular aspect of the "One Health" idea requires more representative surveillance efforts and infection control strategies with respect to animal-species specific characters. Copyright © 2016 Elsevier B.V. All rights reserved.

Using open-access taxonomic and spatial information to create a comprehensive database for the study of mammalian and avian livestock and pet infections.

PubMed

McIntyre, K M; Setzkorn, C; Wardeh, M; Hepworth, P J; Radford, A D; Baylis, M

2014-10-01

What are all the species of pathogen that affect our livestock? As 6 out of every 10 human pathogens came from animals, with a good number from livestock and pets, it seems likely that the majority that emerge in the future, and which could threaten or devastate human health, will come from animals. Only 10 years ago, the first comprehensive pathogen list was compiled for humans; we still have no equivalent for animals. Here we describe the creation of a novel pathogen database, and present outputs from the database that demonstrate its value. The ENHanCEd Infectious Diseases database (EID2) is open-access and evidence-based, and it describes the pathogens of humans and animals, their host and vector species, and also their global occurrence. The EID2 systematically collates information on pathogens into a single resource using evidence from the NCBI Taxonomy database, the NCBI Nucleotide database, the NCBI MeSH (Medical Subject Headings) library and PubMed. Information about pathogens is assigned using data-mining of meta-data and semi-automated literature searches. Here we focus on 47 mammalian and avian hosts, including humans and animals commonly used in Europe as food or kept as pets. Currently, the EID2 evidence suggests that: • Within these host species, 793 (30.5%) pathogens were bacteria species, 395 (15.2%) fungi, 705 (27.1%) helminths, 372 (14.3%) protozoa and 332 (12.8%) viruses. • The odds of pathogens being emerging compared to not emerging differed by taxonomic division, and increased when pathogens had greater numbers of host species associated with them, and were zoonotic rather than non-zoonotic. • The odds of pathogens being zoonotic compared to non-zoonotic differed by taxonomic division and also increased when associated with greater host numbers. • The pathogens affecting the greatest number of hosts included: Escherichia coli, Giardia intestinalis, Toxoplasma gondii, Anaplasma phagocytophilum, Cryptosporidium parvum, Rabies virus, Staphylococcus aureus, Neospora caninum and Echinococcus granulosus. • The pathogens of humans and domestic animal hosts are characterised by 4223 interactions between pathogen and host species, with the greatest number found in: humans, sheep/goats, cattle, small mammals, pigs, dogs and equids. • The number of pathogen species varied by European country. The odds of a pathogen being found in Europe compared to the rest of the world differed by taxonomic division, and increased if they were emerging compared to not emerging, or had a larger number of host species associated with them. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

Whole-Genome Sequences of Staphylococcus haemolyticus Isolated from Infected Eyes and Healthy Conjunctiva in Bhubaneswar, India.

PubMed

Panda, Sasmita; Singh, Durg V

2016-03-17

Staphylococcus haemolyticus, an opportunistic pathogen, is known to exhibit multidrug resistance and produce biofilm. We sequenced the genome of four multidrug resistant, biofilm forming isolates from infected eyes and asymptomatic healthy conjunctiva. Copyright © 2016 Panda and Singh.

Staphylococcus aureus Strain Newman Photoinactivation and Cellular Response to Sunlight Exposure.

PubMed

McClary, Jill S; Sassoubre, Lauren M; Boehm, Alexandria B

2017-09-01

Sunlight influences microbial water quality of surface waters. Previous studies have investigated photoinactivation mechanisms and cellular photostress responses of fecal indicator bacteria (FIB), including Escherichia coli and enterococci, but further work is needed to characterize photostress responses of bacterial pathogens. Here we investigate the photoinactivation of Staphylococcus aureus (strain Newman), a pigmented, waterborne pathogen of emerging concern. We measured photodecay using standard culture-based assays and cellular membrane integrity and investigated photostress response by measuring the relative number of mRNA transcripts of select oxidative stress, DNA repair, and metabolism genes. Photoinactivation experiments were performed in both oxic and anoxic systems to further investigate the role of oxygen-mediated and non-oxygen-mediated photoinactivation mechanisms. S. aureus lost culturability much faster in oxic systems than in anoxic systems, indicating an important role for oxygen in photodecay mechanisms. S. aureus cell membranes were damaged by sunlight exposure in anoxic systems but not in oxic systems, as measured by cell membrane permeability to propidium iodide. After sunlight exposure, S. aureus increased expression of a gene coding for methionine sulfoxide reductase after 12 h of sunlight exposure in the oxic system and after 6 h of sunlight exposure in the anoxic system, suggesting that methionine sulfoxide reductase is an important enzyme for defense against both oxygen-dependent and oxygen-independent photostresses. This research highlights the importance of oxygen in bacterial photoinactivation in environmentally relevant systems and the complexity of the bacterial photostress response with respect to cell structure and transcriptional regulation. IMPORTANCE Staphylococcus aureus is a pathogenic bacterium that causes gastrointestinal, respiratory, and skin infections. In severe cases, S. aureus infection can lead to life-threatening diseases, including pneumonia and sepsis. Cases of community-acquired S. aureus infection have been increasing in recent years, pointing to the importance of considering S. aureus transmission pathways outside the hospital environment. Associations have been observed between recreational water contact and staphylococcal skin infections, suggesting that recreational waters may be an important environmental transmission pathway for S. aureus However, prediction of human health risk in recreational waters is hindered by incomplete knowledge of pathogen sources, fate, and transport in this environment. This study is an in-depth investigation of the inactivation of a representative strain of S. aureus by sunlight exposure, one of the most important factors controlling the fate of microbial contaminants in clear waters, which will improve our ability to predict water quality changes and human health risk in recreational waters. Copyright © 2017 American Society for Microbiology.

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

PubMed

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

2011-06-01

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

Solonamide B Inhibits Quorum Sensing and Reduces Staphylococcus aureus Mediated Killing of Human Neutrophils

PubMed Central

Nielsen, Anita; Månsson, Maria; Bojer, Martin S.; Gram, Lone; Larsen, Thomas O.; Novick, Richard P.; Frees, Dorte; Frøkiær, Hanne; Ingmer, Hanne

2014-01-01

Methicillin-resistant Staphylococcus aureus (MRSA) continues to be a serious human pathogen, and particularly the spread of community associated (CA)-MRSA strains such as USA300 is a concern, as these strains can cause severe infections in otherwise healthy adults. Recently, we reported that a cyclodepsipeptide termed Solonamide B isolated from the marine bacterium, Photobacterium halotolerans strongly reduces expression of RNAIII, the effector molecule of the agr quorum sensing system. Here we show that Solonamide B interferes with the binding of S. aureus autoinducing peptides (AIPs) to sensor histidine kinase, AgrC, of the agr two-component system. The hypervirulence of USA300 has been linked to increased expression of central virulence factors like α-hemolysin and the phenol soluble modulins (PSMs). Importantly, in strain USA300 Solonamide B dramatically reduced the activity of α-hemolysin and the transcription of psma encoding PSMs with an 80% reduction in toxicity of supernatants towards human neutrophils and rabbit erythrocytes. To our knowledge this is the first report of a compound produced naturally by a Gram-negative marine bacterium that interferes with agr and affects both RNAIII and AgrA controlled virulence gene expression in S. aureus. PMID:24416329

Prevalence and Risk Factors of Colonization with Staphylococcus aureus in Healthy Pet Cats Kept in the City Households

PubMed Central

Płoneczka-Janeczko, Katarzyna; Rypuła, Krzysztof

2016-01-01

Staphylococcus aureus, especially methicillin-resistant S. aureus (MRSA), is a significant pathogen in both human medicine and veterinary medicine. The importance of pets as reservoirs of human infections is still poorly understood. This article provides detailed information of a cross-sectional study of a S. aureus colonization in clinically healthy indoor cats. The study systematically assessed a number of different anatomical locations for the S. aureus colonization and the influence of a range of potential risk factors on the value of the final S. aureus colonization rate. The incidence rates observed for cats with at least one site positive for S. aureus or MRSA were 17.5% and 6.63%, respectively. The following risk factors were identified: one or more owners working in the healthcare industry (human or veterinary); dogs being kept with the cat under investigation; treatment of the cat under investigation with antibiotics or chemotherapeutics during the previous year. In conclusion, this study revealed a higher prevalence of MRSA than what has previously been reported in healthy pets. A combination of anatomical locations from which the samples were collected had a major influence on the final value of the S. aureus colonization rate. PMID:27766257

Sensitization of Staphylococcus aureus to methicillin and other antibiotics in vitro and in vivo in the presence of HAMLET.

PubMed

Marks, Laura R; Clementi, Emily A; Hakansson, Anders P

2013-01-01

HAMLET (human alpha-lactalbumin made lethal to tumor cells) is a protein-lipid complex from human milk with both tumoricidal and bactericidal activities. HAMLET exerts a rather specific bactericidal activity against some respiratory pathogens, with highest activity against Streptococcus pneumoniae, but lacks activity against most other bacterial pathogens, including Staphylococci. Still, ion transport associated with death in S. pneumoniae is also detected to a lower degree in insensitive organisms. In this study we demonstrate that HAMLET acts as an antimicrobial adjuvant that can increase the activity of a broad spectrum of antibiotics (methicillin, vancomycin, gentamicin and erythromycin) against multi-drug resistant Staphylococcus aureus, to a degree where they become sensitive to those same antibiotics, both in antimicrobial assays against planktonic and biofilm bacteria and in an in vivo model of nasopharyngeal colonization. We show that HAMLET exerts these effects specifically by dissipating the proton gradient and inducing a sodium-dependent calcium influx that partially depolarizes the plasma membrane, the same mechanism induced during pneumococcal death. These effects results in an increased cell associated binding and/or uptake of penicillin, gentamicin and vancomycin, especially in resistant stains. Finally, HAMLET inhibits the increased resistance of methicillin seen under antibiotic pressure and the bacteria do not become resistant to the adjuvant, which is a major advantageous feature of the molecule. These results highlight HAMLET as a novel antimicrobial adjuvant with the potential to increase the clinical usefulness of antibiotics against drug resistant strains of S. aureus.

Infectious Risk Assessment of Unsafe Handling Practices and Management of Clinical Solid Waste

PubMed Central

Hossain, Md. Sohrab; Rahman, Nik Norulaini Nik Ab; Balakrishnan, Venugopal; Puvanesuaran, Vignesh R.; Sarker, Md. Zaidul Islam; Kadir, Mohd Omar Ab

2013-01-01

The present study was undertaken to determine the bacterial agents present in various clinical solid wastes, general waste and clinical sharp waste. The waste was collected from different wards/units in a healthcare facility in Penang Island, Malaysia. The presence of bacterial agents in clinical and general waste was determined using the conventional bacteria identification methods. Several pathogenic bacteria including opportunistic bacterial agent such as Pseudomonas aeruginosa, Salmonella spp., Klebsiella pneumoniae, Serratia marcescens, Acinetobacter baumannii, Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Streptococcus pyogenes were detected in clinical solid wastes. The presence of specific pathogenic bacterial strains in clinical sharp waste was determined using 16s rDNA analysis. In this study, several nosocomial pathogenic bacteria strains of Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Lysinibacillus sphaericus, Serratia marcescens, and Staphylococcus aureus were detected in clinical sharp waste. The present study suggests that waste generated from healthcare facilities should be sterilized at the point of generation in order to eliminate nosocomial infections from the general waste or either of the clinical wastes. PMID:23435587

Surface adhesion and confinement variation of Staphylococcus aurius on SAM surfaces

NASA Astrophysics Data System (ADS)

Amroski, Alicia; Olsen, Morgan; Calabrese, Joseph; Senevirathne, Reshani; Senevirathne, Indrajith

2012-02-01

Controlled surface adhesion of non - pathogenic gram positive strain, Staphylococcus aureus is interesting as a model system due to possible development of respective biosensors for prevention and detection of the pathogenic strain methicillin resistant Staphylococcus aureus (MRSA) and further as a study for bio-machine interfacing. Self Assembled Monolayers (SAM) with engineered surfaces of linear thiols on Au(111) were used as the substrate. Sub cultured S. aureus were used for the analysis. The SAM layered surfaces were dipped in 2 -- 4 Log/ml S. aureus solution. Subsequent surface adhesion at different bacterial dilutions on surfaces will be discussed, and correlated with quantitative and qualitative adhesion properties of bacteria on the engineered SAM surfaces. The bacteria adhered SAM surfaces were investigated using intermittent contact, noncontact, lateral force and contact modes of Atomic Force Microscopy (AFM).

Staphylococcus aureus utilizes host-derived lipoprotein particles as sources of exogenous fatty acids.

PubMed

Delekta, Phillip C; Shook, John C; Lydic, Todd A; Mulks, Martha H; Hammer, Neal D

2018-03-26

Methicillin-resistant Staphylococcus aureus (MRSA) is a threat to global health. Consequently, much effort has focused on the development of new antimicrobials that target novel aspects of S. aureus physiology. Fatty acids are required to maintain cell viability, and bacteria synthesize fatty acids using the type II fatty acid synthesis pathway (FASII). FASII is significantly different from human fatty acid synthesis, underscoring the therapeutic potential of inhibiting this pathway. However, many Gram-positive pathogens incorporate exogenous fatty acids, bypassing FASII inhibition and leaving the clinical potential of FASII inhibitors uncertain. Importantly, the source(s) of fatty acids available to pathogens within the host environment remains unclear. Fatty acids are transported throughout the body by lipoprotein particles in the form of triglycerides and esterified cholesterol. Thus, lipoproteins, such as low-density lipoprotein (LDL) represent a potentially rich source of exogenous fatty acids for S. aureus during infection. We sought to test the ability of LDLs to serve as a fatty acid source for S. aureus and show that cells cultured in the presence of human LDLs demonstrate increased tolerance to the FASII inhibitor, triclosan. Using mass spectrometry, we observed that host-derived fatty acids present in the LDLs are incorporated into the staphylococcal membrane and that tolerance to triclosan is facilitated by the fatty acid kinase A, FakA, and Geh, a triacylglycerol lipase. Finally, we demonstrate that human LDLs support the growth of S. aureus fatty acid auxotrophs. Together, these results suggest that human lipoprotein particles are a viable source of exogenous fatty acids for S. aureus during infection. IMPORTANCE Inhibition of bacterial fatty acid synthesis is a promising approach to combating infections caused by S. aureus and other human pathogens. However, S. aureus incorporates exogenous fatty acids into its phospholipid bilayer. Therefore, the clinical utility of targeting bacterial fatty acid synthesis is debated. Moreover, the fatty acid reservoir(s) exploited by S. aureus are not well understood. Human low-density lipoprotein particles represent a particularly abundant in vivo source of fatty acids and are present in tissues S. aureus colonizes. Herein, we establish that S. aureus is capable of utilizing the fatty acids present in low-density lipoproteins to bypass both chemical and genetic inhibition of fatty acid synthesis. These findings imply that S. aureus targets LDLs as a source of fatty acids during pathogenesis. Copyright © 2018 American Society for Microbiology.

Comparative Genomics and Identification of an Enterotoxin-Bearing Pathogenicity Island, SEPI-1/SECI-1, in Staphylococcus epidermidis Pathogenic Strains.

PubMed

Argemi, Xavier; Nanoukon, Chimène; Affolabi, Dissou; Keller, Daniel; Hansmann, Yves; Riegel, Philippe; Baba-Moussa, Lamine; Prévost, Gilles

2018-02-25

Staphylococcus epidermidis is a leading cause of nosocomial infections, majorly resistant to beta-lactam antibiotics, and may transfer several mobile genetic elements among the members of its own species, as well as to Staphylococcus aureus ; however, a genetic exchange from S. aureus to S. epidermidis remains controversial. We recently identified two pathogenic clinical strains of S. epidermidis that produce a staphylococcal enterotoxin C3-like (SEC) similar to that by S. aureus pathogenicity islands. This study aimed to determine the genetic environment of the SEC-coding sequence and to identify the mobile genetic elements. Whole-genome sequencing and annotation of the S. epidermidis strains were performed using Illumina technology and a bioinformatics pipeline for assembly, which provided evidence that the SEC-coding sequences were located in a composite pathogenicity island that was previously described in the S. epidermidis strain FRI909, called SePI-1/SeCI-1, with 83.8-89.7% nucleotide similarity. Various other plasmids were identified, particularly p_3_95 and p_4_95, which carry antibiotic resistance genes ( hsrA and dfrG , respectively), and share homologies with SAP085A and pUSA04-2-SUR11, two plasmids described in S. aureus . Eventually, one complete prophage was identified, ΦSE90, sharing 30 out of 52 coding sequences with the Acinetobacter phage vB_AbaM_IME200. Thus, the SePI-1/SeCI-1 pathogenicity island was identified in two pathogenic strains of S. epidermidis that produced a SEC enterotoxin causing septic shock. These findings suggest the existence of in vivo genetic exchange from S. aureus to S. epidermidis .

Comparative Genomics and Identification of an Enterotoxin-Bearing Pathogenicity Island, SEPI-1/SECI-1, in Staphylococcus epidermidis Pathogenic Strains

PubMed Central

Nanoukon, Chimène; Affolabi, Dissou; Keller, Daniel; Hansmann, Yves; Riegel, Philippe; Baba-Moussa, Lamine; Prévost, Gilles

2018-01-01

Staphylococcus epidermidis is a leading cause of nosocomial infections, majorly resistant to beta-lactam antibiotics, and may transfer several mobile genetic elements among the members of its own species, as well as to Staphylococcus aureus; however, a genetic exchange from S. aureus to S. epidermidis remains controversial. We recently identified two pathogenic clinical strains of S. epidermidis that produce a staphylococcal enterotoxin C3-like (SEC) similar to that by S. aureus pathogenicity islands. This study aimed to determine the genetic environment of the SEC-coding sequence and to identify the mobile genetic elements. Whole-genome sequencing and annotation of the S. epidermidis strains were performed using Illumina technology and a bioinformatics pipeline for assembly, which provided evidence that the SEC-coding sequences were located in a composite pathogenicity island that was previously described in the S. epidermidis strain FRI909, called SePI-1/SeCI-1, with 83.8–89.7% nucleotide similarity. Various other plasmids were identified, particularly p_3_95 and p_4_95, which carry antibiotic resistance genes (hsrA and dfrG, respectively), and share homologies with SAP085A and pUSA04-2-SUR11, two plasmids described in S. aureus. Eventually, one complete prophage was identified, ΦSE90, sharing 30 out of 52 coding sequences with the Acinetobacter phage vB_AbaM_IME200. Thus, the SePI-1/SeCI-1 pathogenicity island was identified in two pathogenic strains of S. epidermidis that produced a SEC enterotoxin causing septic shock. These findings suggest the existence of in vivo genetic exchange from S. aureus to S. epidermidis. PMID:29495323

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

PubMed

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

2000-05-01

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

Antimicrobial resistance profile of Staphylococcus aureus isolated from clinical samples and foods of animal origin.

PubMed

Yucel, Nihal; Citak, Sumru; Bayhün, Sinem

2011-03-01

Staphylococcus aureus has been well established as a clinical and epidemiological pathogen and can cause infections at many anatomical sites. Increasing insusceptibility to β-lactams and the glycopeptides complicates the treatment of these infections. We isolated 584 strains of S. aureus from various clinical and animal origin food samples during (from January 2006 to December 2007) the survey. Resistance to 15 antibiotics frequently used in human medicine and veterinary practice was also determined. A remarkable level of penicillin resistance was detected in both clinical (98.3%) and food (92.0%) S. aureus isolates. But, there were no S. aureus strains that were resistant to vancomycin, teicoplanin, linezolid, and quinupristin/dalfobristin. The rate of resistance to tetracycline, ciprofloxacin, levofloxacin, methicillin, gentamicin, tobramycin, norfloxacin, and moxifloxacin among the human and foods S. aureus isolates ranged from 50.3% to 56.3% and 1.4% to 9.5%, respectively. In our survey, in vitro susceptibility data suggested that the incidence of resistance among the S. aureus strains isolated from food were not remarkably high, excluding penicillin. Although the transfer of antibiotic resistance of S. aureus from foods to humans probably occurs less frequently than is generally assumed, the increasing prevalence of resistance in the strains of human origin may have important therapeutic implications.

Disinfection of the Water Borne Pathogens Escherichia coli and Staphylococcus aureus by Solar Photocatalysis Using Sonochemically Synthesized Reusable Ag@ZnO Core-Shell Nanoparticles.

PubMed

Das, Sourav; Ranjana, Neha; Misra, Ananyo Jyoti; Suar, Mrutyunjay; Mishra, Amrita; Tamhankar, Ashok J; Lundborg, Cecilia Stålsby; Tripathy, Suraj K

2017-07-10

Water borne pathogens present a threat to human health and their disinfection from water poses a challenge, prompting the search for newer methods and newer materials. Disinfection of the Gram-negative bacterium Escherichia coli and the Gram-positive coccal bacterium Staphylococcus aureus in an aqueous matrix was achieved within 60 and 90 min, respectively, at 35 °C using solar-photocatalysis mediated by sonochemically synthesized Ag@ZnO core-shell nanoparticles. The efficiency of the process increased with the increase in temperature and at 55 °C the disinfection for the two bacteria could be achieved in 45 and 60 min, respectively. A new ultrasound-assisted chemical precipitation technique was used for the synthesis of Ag@ZnO core-shell nanoparticles. The characteristics of the synthesized material were established using physical techniques. The material remained stable even at 400 °C. Disinfection efficiency of the Ag@ZnO core-shell nanoparticles was confirmed in the case of real world samples of pond, river, municipal tap water and was found to be better than that of pure ZnO and TiO₂ (Degussa P25). When the nanoparticle- based catalyst was recycled and reused for subsequent disinfection experiments, its efficiency did not change remarkably, even after three cycles. The sonochemically synthesized Ag@ZnO core-shell nanoparticles thus have a good potential for application in solar photocatalytic disinfection of water borne pathogens.

In vitro synergistic activities of cefazolin and nisin A against mastitis pathogens.

PubMed

Kitazaki, Kohei; Koga, Shoko; Nagatoshi, Kohei; Kuwano, Koichi; Zendo, Takeshi; Nakayama, Jiro; Sonomoto, Kenji; Ano, Hitoshi; Katamoto, Hiromu

2017-09-12

First-generation cephalosporins such as cefazolin (CEZ) have been widely used for mastitis treatment in dairy cattle. However, the use of antibiotics results in the presence of antibiotic residues in milk, which is used for human consumption. Nisin A, a bacteriocin produced by Lactococcus lactis, has been used as a broad-spectrum food preservative for over 50 years. Therefore, a combination of CEZ and nisin A might provide an extended activity spectrum against mastitis pathogens and reduce the antibiotic dose for mastitis treatment. This study aimed to evaluate the combined effect of CEZ and nisin A against mastitis pathogens using the checkerboard and time-kill assays. In the checkerboard assay, the CEZ-nisin A combination exhibited a synergistic effect against Staphylococcus aureus (n=20/20) and Enterococcus faecalis (n=13/18), and meanwhile exhibited a mostly additive effect against Staphylococcus intermedius (n=12/20), Streptococcus agalactiae (n=10/10), Streptococcus dysgalactiae (n=18/18), and Escherichia coli (n=14/18). There were no indifferent or antagonistic effects between CEZ and nisin A. In the time-kill assay, the CEZ-nisin A combination at 0.5 × or 1 × minimum inhibitory concentration exhibited synergistic reduction of bacterial growth by over 3 log 10 colony forming units per ml relative to that observed with either antimicrobial substance alone. These results suggest that the CEZ-nisin A combination can be used for developing an intramammary infusion for mastitis treatment, with lower antibiotic concentrations than normal.

In vitro synergistic activities of cefazolin and nisin A against mastitis pathogens

PubMed Central

KITAZAKI, Kohei; KOGA, Shoko; NAGATOSHI, Kohei; KUWANO, Koichi; ZENDO, Takeshi; NAKAYAMA, Jiro; SONOMOTO, Kenji; ANO, Hitoshi; KATAMOTO, Hiromu

2017-01-01

First-generation cephalosporins such as cefazolin (CEZ) have been widely used for mastitis treatment in dairy cattle. However, the use of antibiotics results in the presence of antibiotic residues in milk, which is used for human consumption. Nisin A, a bacteriocin produced by Lactococcus lactis, has been used as a broad-spectrum food preservative for over 50 years. Therefore, a combination of CEZ and nisin A might provide an extended activity spectrum against mastitis pathogens and reduce the antibiotic dose for mastitis treatment. This study aimed to evaluate the combined effect of CEZ and nisin A against mastitis pathogens using the checkerboard and time-kill assays. In the checkerboard assay, the CEZ-nisin A combination exhibited a synergistic effect against Staphylococcus aureus (n=20/20) and Enterococcus faecalis (n=13/18), and meanwhile exhibited a mostly additive effect against Staphylococcus intermedius (n=12/20), Streptococcus agalactiae (n=10/10), Streptococcus dysgalactiae (n=18/18), and Escherichia coli (n=14/18). There were no indifferent or antagonistic effects between CEZ and nisin A. In the time-kill assay, the CEZ-nisin A combination at 0.5 × or 1 × minimum inhibitory concentration exhibited synergistic reduction of bacterial growth by over 3 log10 colony forming units per ml relative to that observed with either antimicrobial substance alone. These results suggest that the CEZ-nisin A combination can be used for developing an intramammary infusion for mastitis treatment, with lower antibiotic concentrations than normal. PMID:28757508

Disinfection of the Water Borne Pathogens Escherichia coli and Staphylococcus aureus by Solar Photocatalysis Using Sonochemically Synthesized Reusable Ag@ZnO Core-Shell Nanoparticles

PubMed Central

Das, Sourav; Ranjana, Neha; Misra, Ananyo Jyoti; Suar, Mrutyunjay; Mishra, Amrita; Tripathy, Suraj K.

2017-01-01

Water borne pathogens present a threat to human health and their disinfection from water poses a challenge, prompting the search for newer methods and newer materials. Disinfection of the Gram-negative bacterium Escherichia coli and the Gram-positive coccal bacterium Staphylococcus aureus in an aqueous matrix was achieved within 60 and 90 min, respectively, at 35 °C using solar-photocatalysis mediated by sonochemically synthesized Ag@ZnO core-shell nanoparticles. The efficiency of the process increased with the increase in temperature and at 55 °C the disinfection for the two bacteria could be achieved in 45 and 60 min, respectively. A new ultrasound-assisted chemical precipitation technique was used for the synthesis of Ag@ZnO core-shell nanoparticles. The characteristics of the synthesized material were established using physical techniques. The material remained stable even at 400 °C. Disinfection efficiency of the Ag@ZnO core-shell nanoparticles was confirmed in the case of real world samples of pond, river, municipal tap water and was found to be better than that of pure ZnO and TiO2 (Degussa P25). When the nanoparticle- based catalyst was recycled and reused for subsequent disinfection experiments, its efficiency did not change remarkably, even after three cycles. The sonochemically synthesized Ag@ZnO core-shell nanoparticles thus have a good potential for application in solar photocatalytic disinfection of water borne pathogens. PMID:28698514

Antimicrobial activity of Ulva reticulata and its endophytes

NASA Astrophysics Data System (ADS)

Dhanya, K. I.; Swati, V. I.; Vanka, Kanth Swaroop; Osborne, W. J.

2016-04-01

Seaweeds are known to exhibit various antimicrobial properties, since it harbours an enormous range of indigenous bioactive compounds. The emergence of drug resistant strains has directed to the identification of prospective metabolites from seaweed and its endophytes, thereby exploiting the properties in resisting bacterial diseases. The current study was aimed to assess the antimicrobial activity of extracts obtained from Ulva reticulate, for which metabolites of Ulva reticulata and its endophytes were extracted and assessed against human pathogens like Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, and Bacillus subtilis. It was observed that the hexane extract of isolate VITDSJ2 was effective against all the tested pathogens but a significant inhibition was observed for Staphylococcus aureus and Escherichia coli. Further, Gas chromatography coupled with Mass spectroscopy (GC-MS) revealed the existence of phenol, 3, 5-bis (1, 1-dimethylethyl) in the crude hexane extract which is well-known to possess antibacterial activity. The effective isolate VITDSJ2 was identified to be the closest neighbour of Pseudomonas stutzeri by phenotypic and genotypic methods. The crude extracts of the seaweed Ulva reticulata was also screened for antibacterial activity and the hexane extract was effective in showing inhibition against all the tested pathogens. The compound in the crude extract of Ulva reticulata was identified as hentriacontane using GC-MS. The extracts obtained from dichloromethane did not show significant activity in comparison with the hexane extracts. Hence the metabolites of Ulva reticulata and the bacterial secondary metabolites of the endophytes could be used in the treatment of bacterial infections.

Evaluation of High-Resolution Melting Curve Analysis of Ligation-Mediated Real-Time PCR, a Rapid Method for Epidemiological Typing of ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter Species) Pathogens

PubMed Central

Ryberg, Anna; Billström, Hanna; Hällgren, Anita; Nilsson, Lennart E.; Marklund, Britt-Inger; Olsson-Liljequist, Barbro; Schön, Thomas

2014-01-01

A single-tube method, ligation-mediated real-time PCR high-resolution melt analysis (LMqPCR HRMA), was modified for the rapid typing of Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp. (ESKAPE) pathogens. A 97% agreement (60/62 isolates) was achieved in comparison to pulsed-field gel electrophoresis (PFGE) results, which indicates that LMqPCR HRMA is a rapid and accurate screening tool for monitoring nosocomial outbreaks. PMID:25232168

Molecular Mechanisms of Bacterial Pathogenicity

NASA Astrophysics Data System (ADS)

Fuchs, Thilo Martin

Cautious optimism has arisen over recent decades with respect to the long struggle against bacteria, viruses, and parasites. This has been offset, however, by a fatal complacency stemming from previous successes such as the development of antimicrobial drugs, the eradication of smallpox, and global immunization programs. Infectious diseases nevertheless remain the world's leading cause of death, killing at least 17 million persons annually [61]. Diarrheal diseases caused by Vibrio cholerae or Shigella dysenteriae kill about 3 million persons every year, most of them young children: Another 4 million die of tuberculosis or tetanus. Outbreaks of diphtheria in Eastern Europe threatens the population with a disease that had previously seemed to be overcome. Efforts to control infectious diseases more comprehensively are undermined not only by socioeconomic conditions but also by the nature of the pathogenic organisms itself; some isolates of Staphylococcus aureus and Enterobacter have become so resistant to drugs by horizontal gene transfer that they are almost untreatable. In addition, the mechanism of genetic variability helps pathogens to evade the human immune system, thus compromising the development of powerful vaccines. Therefore detailed knowledge of the molecular mechanisms of microbial pathogenicity is absolutely necessary to develop new strategies against infectious diseases and thus to lower their impact on human health and social development.

Effect of United States buckwheat honey on antibiotic-resistant hospital acquired pathogens

PubMed Central

Hammond, Eric Nee-Armah; Duster, Megan; Musuuza, Jackson Ssentalo; Safdar, Nasia

2016-01-01

Introduction Due to an upsurge in antibiotic-resistant infections and lack of therapeutic options, new approaches are needed for treatment. Honey may be one such potential therapeutic option. We investigated the susceptibility of hospital acquired pathogens to four honeys from Wisconsin, United States, and then determined if the antibacterial effect of each honey against these pathogens is primarily due to the high sugar content. Methods Thirteen pathogens including: four Clostridium difficile, two Methicillin-resistant Staphylococcus aureus, two Pseudomonas aeruginosa, one Methicillin-Susceptible Staphylococcus aureus, two Vancomycin-resistance Enterococcus, one Enterococcus faecalis and one Klebsiella pneumoniae were exposed to 1-50% (w/v) four Wisconsin honeys and Artificial honey to determine their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using the broth dilution method. Results Buckwheat honey predominantly exhibited a bactericidal mode of action against the tested pathogens, and this varied with each pathogen. C. difficile isolates were more sensitive to the Wisconsin buckwheat honey as compared to the other pathogens. Artificial honey at 50% (w/v) failed to kill any of the pathogens. The high sugar content of Wisconsin buckwheat honey is not the only factor responsible for its bactericidal activity. Conclusion Wisconsin buckwheat honey has the potential to be an important addition to therapeutic armamentarium against resistant pathogens and should be investigated further. PMID:28292167

Methicillin-resistant food-related Staphylococcus aureus: a review of current knowledge and biofilm formation for future studies and applications.

PubMed

Doulgeraki, Agapi I; Di Ciccio, Pierluigi; Ianieri, Adriana; Nychas, George-John E

2017-01-01

There is increasing concern about the public health impact of methicillin-resistant Staphylococcus aureus. Food and animal are vectors of transmission, but the contribution of a contaminated environment is not well characterized. With regard to this, staphylococcal biofilms serve as a virulence factor, allowing MRSA strains to adhere to surfaces and other materials used in the food industry. Methicillin resistance and biofilm-forming capacity may contribute to the success of S. aureus as a human pathogen in both health care and community settings and the food production chain. This review summarizes current knowledge about the significance of food- and animal-derived MRSA strains and provides data on attachment and biofilm formation of MRSA. In addition, the impact of quorum sensing on MRSA gene expression and biofilm formation is examined. Copyright © 2016. Published by Elsevier Masson SAS.

Vancomycin-Resistant Gram-Positive Cocci Isolated from the Saliva of Wild Songbirds

PubMed Central

Ishihara, Shingo; Bitner, Jessica J.; Farley, Greg H.

2014-01-01

We analyzed highly vancomycin-resistant Gram-positive bacteria isolated from the saliva of migratory songbirds captured, sampled, and released from a birdbanding station in western Kansas. Individual bacterial isolates were identified by partial 16S rRNA sequencing. Most of the bacteria in this study were shown to be Staphylococcus succinus with the majority being isolated from the American Robin. Some of these bacteria were shown to carry vanA, vanB, and vanC vancomycin-resistance genes and have the ability to form biofilms. One of the van gene-carrying isolates is also coagulase positive, which is normally considered a virulence factor. Other organisms isolated included Staphylococcus saprophyticus as well as Enterococcus gallinarum. Given the wide range of the American Robin and ease of horizontal gene transfer between Gram-positive cocci, we postulate that these organisms could serve as a reservoir of vancomycin-resistance genes capable of transferring to human pathogens. PMID:23224296

Vancomycin-resistant gram-positive cocci isolated from the saliva of wild songbirds.

PubMed

Ishihara, Shingo; Bitner, Jessica J; Farley, Greg H; Gillock, Eric T

2013-04-01

We analyzed highly vancomycin-resistant Gram-positive bacteria isolated from the saliva of migratory songbirds captured, sampled, and released from a bird-banding station in western Kansas. Individual bacterial isolates were identified by partial 16S rRNA sequencing. Most of the bacteria in this study were shown to be Staphylococcus succinus with the majority being isolated from the American Robin. Some of these bacteria were shown to carry vanA, vanB, and vanC vancomycin-resistance genes and have the ability to form biofilms. One of the van gene-carrying isolates is also coagulase positive, which is normally considered a virulence factor. Other organisms isolated included Staphylococcus saprophyticus as well as Enterococcus gallinarum. Given the wide range of the American Robin and ease of horizontal gene transfer between Gram-positive cocci, we postulate that these organisms could serve as a reservoir of vancomycin-resistance genes capable of transferring to human pathogens.

Molecular coordination of Staphylococcus aureus cell division

PubMed Central

Cotterell, Bryony E; Walther, Christa G; Fenn, Samuel J; Grein, Fabian; Wollman, Adam JM; Leake, Mark C; Olivier, Nicolas; Cadby, Ashley; Mesnage, Stéphane; Jones, Simon

2018-01-01

The bacterial cell wall is essential for viability, but despite its ability to withstand internal turgor must remain dynamic to permit growth and division. Peptidoglycan is the major cell wall structural polymer, whose synthesis requires multiple interacting components. The human pathogen Staphylococcus aureus is a prolate spheroid that divides in three orthogonal planes. Here, we have integrated cellular morphology during division with molecular level resolution imaging of peptidoglycan synthesis and the components responsible. Synthesis occurs across the developing septal surface in a diffuse pattern, a necessity of the observed septal geometry, that is matched by variegated division component distribution. Synthesis continues after septal annulus completion, where the core division component FtsZ remains. The novel molecular level information requires re-evaluation of the growth and division processes leading to a new conceptual model, whereby the cell cycle is expedited by a set of functionally connected but not regularly distributed components. PMID:29465397

Dipeptide cis-cyclo(Leucyl-Tyrosyl) produced by sponge associated Penicillium sp. F37 inhibits biofilm formation of the pathogenic Staphylococcus epidermidis.

PubMed

Scopel, Marina; Abraham, Wolf-Rainer; Henriques, Amélia T; Macedo, Alexandre J

2013-02-01

Infections associated to microbial biofilms are involved in 80% of human infections and became a challenge concerning public health. Infections related to Staphylococcus epidermidis biofilms are presently commonly associated to medical devices, increasing treatment costs for this type of infection. Alternatives to eliminate this kind of disease have been employed in screening programs using diverse marine-derived fungi source of bioactive compounds capable to combat biofilm formation. In this work was isolated the dipeptide cis-cyclo(Leucyl-Tyrosyl) from a sponge associated Penicillium sp. possessing a remarkable inhibition up to 85% of biofilm formation without interfering with bacterial growth, confirmed by scanning electron microscopy. This is the first demonstration that cis-cyclo(Leucyl-Tyrosyl) is able to specifically inhibit biofilm formation adding another aspect to the broad spectrum of bioactivities of cyclic dipeptides. Copyright © 2012 Elsevier Ltd. All rights reserved.

Sensory deprivation in Staphylococcus aureus.

PubMed

Villanueva, Maite; García, Begoña; Valle, Jaione; Rapún, Beatriz; Ruiz de Los Mozos, Igor; Solano, Cristina; Martí, Miguel; Penadés, José R; Toledo-Arana, Alejandro; Lasa, Iñigo

2018-02-06

Bacteria use two-component systems (TCSs) to sense and respond to environmental changes. The core genome of the major human pathogen Staphylococcus aureus encodes 16 TCSs, one of which (WalRK) is essential. Here we show that S. aureus can be deprived of its complete sensorial TCS network and still survive under growth arrest conditions similarly to wild-type bacteria. Under replicating conditions, however, the WalRK system is necessary and sufficient to maintain bacterial growth, indicating that sensing through TCSs is mostly dispensable for living under constant environmental conditions. Characterization of S. aureus derivatives containing individual TCSs reveals that each TCS appears to be autonomous and self-sufficient to sense and respond to specific environmental cues, although some level of cross-regulation between non-cognate sensor-response regulator pairs occurs in vivo. This organization, if confirmed in other bacterial species, may provide a general evolutionarily mechanism for flexible bacterial adaptation to life in new niches.

Staphylococcus aureus Infections: Epidemiology, Pathophysiology, Clinical Manifestations, and Management

PubMed Central

Davis, Joshua S.; Eichenberger, Emily; Holland, Thomas L.

2015-01-01

SUMMARY Staphylococcus aureus is a major human pathogen that causes a wide range of clinical infections. It is a leading cause of bacteremia and infective endocarditis as well as osteoarticular, skin and soft tissue, pleuropulmonary, and device-related infections. This review comprehensively covers the epidemiology, pathophysiology, clinical manifestations, and management of each of these clinical entities. The past 2 decades have witnessed two clear shifts in the epidemiology of S. aureus infections: first, a growing number of health care-associated infections, particularly seen in infective endocarditis and prosthetic device infections, and second, an epidemic of community-associated skin and soft tissue infections driven by strains with certain virulence factors and resistance to β-lactam antibiotics. In reviewing the literature to support management strategies for these clinical manifestations, we also highlight the paucity of high-quality evidence for many key clinical questions. PMID:26016486

Mobile genetic elements of Staphylococcus aureus.

PubMed

Malachowa, Natalia; DeLeo, Frank R

2010-09-01

Bacteria such as Staphylococcus aureus are successful as commensal organisms or pathogens in part because they adapt rapidly to selective pressures imparted by the human host. Mobile genetic elements (MGEs) play a central role in this adaptation process and are a means to transfer genetic information (DNA) among and within bacterial species. Importantly, MGEs encode putative virulence factors and molecules that confer resistance to antibiotics, including the gene that confers resistance to beta-lactam antibiotics in methicillin-resistant S. aureus (MRSA). Inasmuch as MRSA infections are a significant problem worldwide and continue to emerge in epidemic waves, there has been significant effort to improve diagnostic assays and to develop new antimicrobial agents for treatment of disease. Our understanding of S. aureus MGEs and the molecules they encode has played an important role toward these ends and has provided detailed insight into the evolution of antimicrobial resistance mechanisms and virulence.

Pathogenesis of Staphylococcus aureus Bloodstream Infections

PubMed Central

Thomer, Lena; Schneewind, Olaf; Missiakas, Dominique

2016-01-01

Staphylococcus aureus , a Gram-positive bacterium colonizing nares, skin, and the gastrointestinal tract, frequently invades the skin, soft tissues, and bloodstreams of humans. Even with surgical and antibiotic therapy, bloodstream infections are associated with significant mortality. The secretion of coagulases, proteins that associate with and activate the host hemostatic factor prothrombin, and the bacterial surface display of agglutinins, proteins that bind polymerized fibrin, are key virulence strategies for the pathogenesis of S. aureus bloodstream infections, which culminate in the establishment of abscess lesions. Pathogen-controlled processes, involving a wide spectrum of secreted factors, are responsible for the recruitment and destruction of immune cells, transforming abscess lesions into purulent exudate, with which staphylococci disseminate to produce new infectious lesions or to infect new hosts. Research on S. aureus bloodstream infections is a frontier for the characterization of protective vaccine antigens and the development of immune therapeutics aiming to prevent disease or improve outcomes. PMID:26925499

Can routine surveillance samples from tracheal aspirate predict bacterial flora in cases of ventilator-associated pneumonia?

PubMed

Lampati, L; Maggioni, E; Langer, M; Malacarne, P; Mozzo, R; Pesenti, A; Fumagalli, R

2009-10-01

The aim of this study was to investigate the hypothesis that periodical sampling of the tracheo-bronchial tree in the absence of clinical suspicion of pneumonia is useful to identify bacteria responsible for subsequent late ventilator associated pneumonia (VAP). This was a retrospective observational human study carried out in two medical-surgical intensive care units of two different hospitals. From January 1999 to December 2000, 559 patients, who received invasive respiratory support for more than 48 hours, were screened. Tracheal aspiration (TA) was performed once or twice weekly in all mechanically ventilated patients. The microbiological findings from TA surveillance cultures done in the eight days before suspicion of VAP were compared to those isolated from the positive diagnostic samples done for late onset VAP (after more than four days of mechanical ventilation). The sensitivity, specificity, and positive/negative predictive values of the ability of the surveillance sample to anticipate the VAP pathogen were calculated. Among the microorganisms isolated from TA, 68% were retrieved from diagnostic samples. All VAP pathogens previously isolated were from 43% of the TA samples. If TA was collected 2-4 days before the clinical diagnosis of VAP, pathogens were detected in 58% of samples. In contrast, only 27% were collected more than four days earlier (P<0.05). The positive predictive values for Pseudomonas aeruginosa and methicillin resistant Staphylococcus aureus from routine TA samples were 92% and 90%, respectively. The negative predictive values for Pseudomonas aeruginosa and methicillin resistant Staphylococcus aureus from routine TA samples were 75% and 89%, respectively. TA cultures in ventilated patients may help to predict pathogens. Early detection may lead to earlier treatment in long term ventilated patients when VAP is suspected.

An Update on Clinical Burden, Diagnostic Tools, and Therapeutic Options of Staphylococcus aureus

PubMed Central

Reddy, Prakash Narayana; Srirama, Krupanidhi; Dirisala, Vijaya R

2017-01-01

Staphylococcus aureus is an important pathogen responsible for a variety of diseases ranging from mild skin and soft tissue infections, food poisoning to highly serious diseases such as osteomyelitis, endocarditis, and toxic shock syndrome. Proper diagnosis of pathogen and virulence factors is important for providing timely intervention in the therapy. Owing to the invasive nature of infections and the limited treatment options due to rampant spread of antibiotic-resistant strains, the trend for development of vaccines and antibody therapy is increasing at rapid rate than development of new antibiotics. In this article, we have discussed elaborately about the host-pathogen interactions, clinical burden due to S aureus infections, status of diagnostic tools, and treatment options in terms of prophylaxis and therapy. PMID:28579798

Characterization of Antibacterial Activities of Eastern Subterranean Termite, Reticulitermes flavipes, against Human Pathogens

PubMed Central

Zeng, Yuan; Hu, Xing Ping

2016-01-01

The emergence and dissemination of multidrug resistant bacterial pathogens necessitate research to find new antimicrobials against these organisms. We investigated antimicrobial production by eastern subterranean termites, Reticulitermes flavipes, against a panel of bacteria including three multidrug resistant (MDR) and four non-MDR human pathogens. We determined that the crude extract of naïve termites had a broad-spectrum activity against the non-MDR bacteria but it was ineffective against the three MDR pathogens Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus (MRSA), and Acinetobacter baumannii. Heat or trypsin treatment resulted in a complete loss of activity suggesting that antibacterial activity was proteinaceous in nature. The antimicrobial activity changed dramatically when the termites were fed with either heat-killed P. aeruginosa or MRSA. Heat-killed P. aeruginosa induced activity against P. aeruginosa and MRSA while maintaining or slightly increasing activity against non-MDR bacteria. Heat-killed MRSA induced activity specifically against MRSA, altered the activity against two other Gram-positive bacteria, and inhibited activity against three Gram-negative bacteria. Neither the naïve termites nor the termites challenged with heat-killed pathogens produced antibacterial activity against A. baumannii. Further investigation demonstrated that hemolymph, not the hindgut, was the primary source of antibiotic activity. This suggests that the termite produces these antibacterial activities and not the hindgut microbiota. Two-dimensional gel electrophoretic analyses of 493 hemolymph protein spots indicated that a total of 38 and 65 proteins were differentially expressed at least 2.5-fold upon being fed with P. aeruginosa and MRSA, respectively. Our results provide the first evidence of constitutive and inducible activities produced by R. flavipes against human bacterial pathogens. PMID:27611223

Methicillin-Resistant "Staphylococcus aureus" on Campus: A New Challenge to College Health

ERIC Educational Resources Information Center

Weiner, H. Richard

2008-01-01

As new drugs to control bacterial pathogens are developed, the organisms evolve to survive. "Staphylococcus aureus", a common organism, has steadily developed resistance to antibiotics. For more than 40 years, resistant "S. aureus" presented a formidable problem to hospitalized patients; in the past decade, however, it has begun to appear outside…

Growth of Staphylococcus aureus in cooked potato and potato salad – A one-step kinetic analysis

USDA-ARS?s Scientific Manuscript database

Staphylococcus aureus is a Gram-positive spherically-shaped bacterium capable of producing heat-stable enterotoxins that cause acute gastrointestinal diseases. The growth of this pathogen in food is a major threat to public health worldwide. Potato salad is a frequent vehicle for infection and foo...

Virulence factors and genetic variability of Staphylococcus aureus strains isolated from raw sheep's milk cheese.

PubMed

Spanu, Vincenzo; Spanu, Carlo; Virdis, Salvatore; Cossu, Francesca; Scarano, Christian; De Santis, Enrico Pietro Luigi

2012-02-01

Contamination of dairy products with Staphylococcus aureus can be of animal or human origin. The host pathogen relationship is an important factor determining genetic polymorphism of the strains and their potential virulence. The aim of the present study was to carry out an extensive characterization of virulence factors and to study the genetic variability of S. aureus strains isolated from raw ewe's milk cheese. A total of 100 S. aureus strains isolated from cheese samples produced in 10 artisan cheese factories were analyzed for the presence of enterotoxins (sea-see) and enterotoxins-like genes (seh, sek, sel, sem, seo, sep), leukocidins, exfoliatins, haemolysins, toxic shock syndrome toxin 1 (TSST-1) and the accessory gene regulator alleles (agr). Strains were also typed using pulsed-field gel electrophoresis (PFGE). AMOVA analysis carried out on PFGE and PCR data showed that the major component explaining genetic distance between strains was the dairy of origin. Of the total isolates 81% had a pathogenicity profile ascribable to "animal" biovar while 16% could be related to "human" biovar. The biovar allowed to estimate the most likely origin of the contamination. Minimum inhibitory concentrations (MICs) of nine antimicrobial agents and the presence of the corresponding genes coding for antibiotic resistance was also investigated. 18 strains carrying blaZ gene showed resistance to ampicillin and penicillin and 6 strains carrying tetM gene were resistant to tetracycline. The presence of mecA gene and methicillin resistance, typical of strains of human origin, was never detected. The results obtained in the present study confirm that S. aureus contamination in artisan cheese production is mainly of animal origin. Copyright © 2011. Published by Elsevier B.V.

Heme Recognition By a Staphylococcus Aureus IsdE

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

Grigg, J.C.; Vermeiren, C.L.; Heinrichs, D.E.

Staphylococcus aureus is a Gram-positive bacterial pathogen and a leading cause of hospital acquired infections. Because the free iron concentration in the human body is too low to support growth, S. aureus must acquire iron from host sources. Heme iron is the most prevalent iron reservoir in the human body and a predominant source of iron for S. aureus. The iron-regulated surface determinant (Isd) system removes heme from host heme proteins and transfers it to IsdE, the cognate substrate-binding lipoprotein of an ATP-binding cassette transporter, for import and subsequent degradation. Herein, we report the crystal structure of the soluble portionmore » of the IsdE lipoprotein in complex with heme. The structure reveals a bi-lobed topology formed by an N- and C-terminal domain bridged by a single {alpha}-helix. The structure places IsdE as a member of the helical backbone metal receptor superfamily. A six-coordinate heme molecule is bound in the groove established at the domain interface, and the heme iron is coordinated in a novel fashion for heme transporters by Met{sup 78} and His{sup 229}. Both heme propionate groups are secured by H-bonds to IsdE main chain and side chain groups. Of these residues, His{sup 299} is essential for IsdE-mediated heme uptake by S. aureus when growth on heme as a sole iron source is measured. Multiple sequence alignments of homologues from several other Gram-positive bacteria, including the human pathogens pyogenes, Bacillus anthracis, and Listeria monocytogenes, suggest that these other systems function equivalently to S. aureus IsdE with respect to heme binding and transport.« less

Clinical significance of the isolation of Staphylococcus epidermidis from bone biopsy in diabetic foot osteomyelitis.

PubMed

Aragón-Sánchez, Javier; Lázaro-Martínez, Jose Luis; Hernández-Herrero, María José; Quintana-Marrero, Yurena; Cabrera-Galván, Juan J

2010-01-01

Coagulase-negative staphylococci are considered as microorganisms with little virulence and usually as contaminants. In order to establish the role of Staphylococcus epidermidis as a pathogen in diabetic foot osteomyelitis, in addition to the isolation of the sole bacterium from the bone it will be necessary to demonstrate the histopathological changes caused by the infection. A consecutive series of 222 diabetic patients with foot osteomyelitis treated surgically in the Diabetic Foot Unit at La Paloma Hospital (Las Palmas de Gran Canaria, Canary Islands, Spain) between 1 October 2002 and 31 October 2008. From the entire series including 213 bone cultures with 241 isolated organisms, we have analyzed only the 139 cases where Staphylococci were found. We analyzed several variables between the two groups: Staphylococcus aureus versus Staphylococcus epidermidis. Of the 134 patients included in this study, Staphlylococcus epidermidis was found as the sole bacterium isolated in 11 cases and accompanied by other bacteria in 12 cases. Staphlylococcus aureus was found as the sole bacterium isolated in 72 cases and accompanied by other bacteria in 39 cases. Histopathological changes were found in the cases of osteomyelitis where Staphylococcus epidermidis was the sole bacterium isolated. Acute osteomyelitis was found to a lesser extent when Staphylococcus epidermidis was the sole bacterium isolated but without significant differences with the cases where Staphylococcus aureus was the sole bacterium isolated. Staphylococcus epidermidis should be considered as a real pathogen, not only a contaminant, in diabetic patients with foot osteomyelitis when the bacterium is isolated from the bone. No differences in the outcomes of surgical treatment have been found with cases which Staphlylococcus aureus was isolated.

Clinical significance of the isolation of Staphylococcus epidermidis from bone biopsy in diabetic foot osteomyelitis

PubMed Central

Aragón-Sánchez, Javier; Lázaro-Martínez, Jose Luis; Hernández-Herrero, María José; Quintana-Marrero, Yurena; Cabrera-Galván, Juan J.

2010-01-01

Introduction Coagulase-negative staphylococci are considered as microorganisms with little virulence and usually as contaminants. In order to establish the role of Staphylococcus epidermidis as a pathogen in diabetic foot osteomyelitis, in addition to the isolation of the sole bacterium from the bone it will be necessary to demonstrate the histopathological changes caused by the infection. Methods A consecutive series of 222 diabetic patients with foot osteomyelitis treated surgically in the Diabetic Foot Unit at La Paloma Hospital (Las Palmas de Gran Canaria, Canary Islands, Spain) between 1 October 2002 and 31 October 2008. From the entire series including 213 bone cultures with 241 isolated organisms, we have analyzed only the 139 cases where Staphylococci were found. We analyzed several variables between the two groups: Staphylococcus aureus versus Staphylococcus epidermidis. Results Of the 134 patients included in this study, Staphlylococcus epidermidis was found as the sole bacterium isolated in 11 cases and accompanied by other bacteria in 12 cases. Staphlylococcus aureus was found as the sole bacterium isolated in 72 cases and accompanied by other bacteria in 39 cases. Histopathological changes were found in the cases of osteomyelitis where Staphylococcus epidermidis was the sole bacterium isolated. Acute osteomyelitis was found to a lesser extent when Staphylococcus epidermidis was the sole bacterium isolated but without significant differences with the cases where Staphylococcus aureus was the sole bacterium isolated. Conclusion Staphylococcus epidermidis should be considered as a real pathogen, not only a contaminant, in diabetic patients with foot osteomyelitis when the bacterium is isolated from the bone. No differences in the outcomes of surgical treatment have been found with cases which Staphlylococcus aureus was isolated. PMID:22396808

An Intracellular Peptidyl-Prolyl cis/trans Isomerase Is Required for Folding and Activity of the Staphylococcus aureus Secreted Virulence Factor Nuclease.

PubMed

Wiemels, Richard E; Cech, Stephanie M; Meyer, Nikki M; Burke, Caleb A; Weiss, Andy; Parks, Anastacia R; Shaw, Lindsey N; Carroll, Ronan K

2017-01-01

Staphylococcus aureus is an important human pathogen that relies on a large repertoire of secreted and cell wall-associated proteins for pathogenesis. Consequently, the ability of the organism to cause disease is absolutely dependent on its ability to synthesize and successfully secrete these proteins. In this study, we investigate the role of peptidyl-prolyl cis/trans isomerases (PPIases) on the activity of the S. aureus secreted virulence factor nuclease (Nuc). We identify a staphylococcal cyclophilin-type PPIase (PpiB) that is required for optimal activity of Nuc. Disruption of ppiB results in decreased nuclease activity in culture supernatants; however, the levels of Nuc protein are not altered, suggesting that the decrease in activity results from misfolding of Nuc in the absence of PpiB. We go on to demonstrate that PpiB exhibits PPIase activity in vitro, is localized to the bacterial cytosol, and directly interacts with Nuc in vitro to accelerate the rate of Nuc refolding. Finally, we demonstrate an additional role for PpiB in S. aureus hemolysis and demonstrate that the S. aureus parvulin-type PPIase PrsA also plays a role in the activity of secreted virulence factors. The deletion of prsA leads to a decrease in secreted protease and phospholipase activity, similar to that observed in other Gram-positive pathogens. Together, these results demonstrate, for the first time to our knowledge, that PPIases play an important role in the secretion of virulence factors in S. aureus IMPORTANCE: Staphylococcus aureus is a highly dangerous bacterial pathogen capable of causing a variety of infections throughout the human body. The ability of S. aureus to cause disease is largely due to an extensive repertoire of secreted and cell wall-associated proteins, including adhesins, toxins, exoenzymes, and superantigens. These virulence factors, once produced, are typically transported across the cell membrane by the secretory (Sec) system in a denatured state. Consequently, once outside the cell, they must refold into their active form. This step often requires the assistance of bacterial folding proteins, such as PPIases. In this work, we investigate the role of PPIases in S. aureus and uncover a cyclophilin-type enzyme that assists in the folding/refolding of staphylococcal nuclease. Copyright © 2016 American Society for Microbiology.

Synthesis and anti-microbial activity of hydroxylammonium ionic liquids.

PubMed

Ismail Hossain, M; El-Harbawi, Mohanad; Noaman, Yousr Abdulhadi; Bustam, Mohd Azmi B; Alitheen, Noorjahan Banu Mohamed; Affandi, Nor Azrin; Hefter, Glenn; Yin, Chun-Yang

2011-06-01

Eight hydroxylammonium-based room temperature ionic liquids (ILs) have been synthesized by acid-base neutralization of ethanolamines with organic acids. The ILs were characterized by infrared and nuclear magnetic resonance spectroscopies and elemental analysis. Their anti-microbial activities were determined using the well-diffusion method. All eight ILs were toxic to Staphylococcus aureus, while 2-hydroxyethylammonium lactate and 2-hydroxy-N-(2-hydroxyethyl)-N-methylethanaminium acetate showed high anti-microbial activity against a wide range of human pathogens. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

[Advances in the study of anti-MRSA natural products].

PubMed

Song, Hao; Qin, Yong

2016-05-01

Methicillin-resistant Staphylococcus aureus (MRSA) is a multi-drug resistant pathogenic bacteria, which has seriously threatened human health for a long time. Discovery of novel anti-MRSA lead compounds with high efficiency and low toxicity represents an important research focus in the realm of antibiotic studies. Owing to their structural diversity and complexity, natural products have exhibited unique advantages and great potential in the development of anti-MRSA new drugs.This review summarizes the studies of anti-MRSA natural products and their relevant medicinal chemistry reported since 2010.

Identification and antimicrobial resistance of pathogens in neonatal septicemia in China-A meta-analysis.

PubMed

Li, Jing-Yang; Chen, Shang-Qin; Yan, Yan-Yan; Hu, Ying-Ying; Wei, Jia; Wu, Qiu-Ping; Lin, Zhen-Lang; Lin, Jing

2018-06-01

The purpose of this study was to analyze the distribution and antimicrobial resistance of common bacterial pathogens causing neonatal septicemia based on a systematic review of published studies in China. Articles on neonatal sepsis published in the Chinese literature from 2009 to 2014 were identified according to the inclusion and exclusion criteria. Data were extracted and analyzed using Comprehensive Meta-Analysis software. A total of 71 studies were included, in which a total of 8080 bacterial species were isolated from culture-positive blood samples. The pooled distribution rates of common bacterial pathogens were as follows: Staphylococcus 67.1% (95% confidence interval (CI) 63.3-70.6%), Enterococcus 4.1% (95% CI 3.5-4.8%), Streptococcus 2.3% (95% CI 1.6-3.2%), Escherichia coli 7.4% (95% CI 6.4-8.7%), Klebsiella 6.5% (95% CI 5.2-8.2%), Enterobacterium 2.3% (95% CI 1.9-2.8%), Acinetobacter 1.6% (95% CI 1.3-2.0%), Pseudomonas 1.7% (95% CI 1.3-2.2%). Among the Staphylococcus aureus strains isolated, more than 60% were methicillin-resistant (MRSA). In addition, over 50% of the Gram-negative isolates, including Escherichia and Klebsiella, were resistant to the commonly used third-generation cephalosporins. Most of the Gram-positive and Gram-negative bacteria isolated were sensitive to aminoglycosides, especially amikacin. It is concluded that Staphylococcus, especially coagulase-negative Staphylococcus, continues to be the principal organism responsible for neonatal septicemia in China; Enterobacteriaceae are common among the Gram-negative isolates. Significant numbers of MRSA and multidrug-resistant Gram-negative bacteria are being isolated as pathogens responsible for neonatal septicemia in China. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

[Molecular study of methicillin-resistant Staphylococcus haemolyticus in a Mexican hospital].

PubMed

Castro, Natividad; Loaiza-Loeza, María Salomé; Calderón-Navarro, Amparo; Sánchez, Alejandro; Silva-Sánchez, Jesús

2006-01-01

To perform the molecular characterization of methicillin-resistant Staphylococcus haemolyticus (MRSH) clinical isolates from patients in a Mexican hospital. Sixty three Staphylococcus ssp. isolates collected from September 2000 to October 2002 were analyzed. Antimicrobial susceptibility was determined by disk diffusion method and the presence of the mecA gene was detected by PCR technique. Isolates characterization was carried out by pulsed field gel electrophoresis (PFGE). The frequency of S. haemolyticus was 25.5% (18 of 63 clinical isolates), all S. haemolyticus isolates were methicillin-resistant and they were positive for the mecA gene. A major pattern (A) with 8 subtypes was identified. This clone was distributed during the 20 months period. Most of them were isolated from the surgery (55%) and pediatric services (27.5%). The methicillin-resistant S. haemolyticus permanence as pathogen in this hospital, suggest the implementation of control programs in order to decrease the prevalence of this multiresistant pathogen.

Emergence of Nasal Carriage of ST80 and ST152 PVL+ Staphylococcus aureus Isolates from Livestock in Algeria

PubMed Central

Agabou, Amir; Ouchenane, Zouleikha; Ngba Essebe, Christelle; Khemissi, Salim; Chehboub, Mohamed Tedj Eddine; Chehboub, Ilyes Bey; Dunyach-Remy, Catherine

2017-01-01

The spread of toxinogenic Staphylococcus aureus is a public health problem in Africa. The objectives of the study were to investigate the rate of S. aureus nasal carriage and molecular characteristics of these strains in livestock and humans in three Algerian provinces. Nasal samples were collected from camels, horses, cattle, sheep and monkeys, as well as humans in contact with them. S. aureus isolates were genotyped using DNA microarray. The rate of S. aureus nasal carriage varied between species: camels (53%), humans and monkeys (50%), sheep (44.2%), horses (15.2%) and cattle (15%). Nine methicillin-resistant S. aureus (MRSA) isolates (7.6%) were identified, isolated from camels and sheep. The S. aureus isolates belonged to 15 different clonal complexes. Among them, PVL+ (Panton–Valentine Leukocidin) isolates belonging to ST80-MRSA-IV and ST152-MSSA were identified in camels (n = 3, 13%) and sheep (n = 4, 21.1%). A high prevalence of toxinogenic animal strains was noted containing TSST-1- (22.2%), EDINB- (29.6%) and EtD- (11.1%) encoding genes. This study showed the dispersal of the highly human pathogenic clones ST152-MSSA and ST-80-MRSA in animals. It suggests the ability of some clones to cross the species barrier and jump between humans and several animal species. PMID:28946704

Selective inhibition of Biotin Protein Ligase from Staphylococcus aureus*

PubMed Central

Soares da Costa, Tatiana P.; Tieu, William; Yap, Min Y.; Pendini, Nicole R.; Polyak, Steven W.; Sejer Pedersen, Daniel; Morona, Renato; Turnidge, John D.; Wallace, John C.; Wilce, Matthew C. J.; Booker, Grant W.; Abell, Andrew D.

2012-01-01

There is a well documented need to replenish the antibiotic pipeline with new agents to combat the rise of drug resistant bacteria. One strategy to combat resistance is to discover new chemical classes immune to current resistance mechanisms that inhibit essential metabolic enzymes. Many of the obvious drug targets that have no homologous isozyme in the human host have now been investigated. Bacterial drug targets that have a closely related human homologue represent a new frontier in antibiotic discovery. However, to avoid potential toxicity to the host, these inhibitors must have very high selectivity for the bacterial enzyme over the human homolog. We have demonstrated that the essential enzyme biotin protein ligase (BPL) from the clinically important pathogen Staphylococcus aureus could be selectively inhibited. Linking biotin to adenosine via a 1,2,3 triazole yielded the first BPL inhibitor selective for S. aureus BPL over the human equivalent. The synthesis of new biotin 1,2,3-triazole analogues using click chemistry yielded our most potent structure (Ki 90 nm) with a >1100-fold selectivity for the S. aureus BPL over the human homologue. X-ray crystallography confirmed the mechanism of inhibitor binding. Importantly, the inhibitor showed cytotoxicity against S. aureus but not cultured mammalian cells. The biotin 1,2,3-triazole provides a novel pharmacophore for future medicinal chemistry programs to develop this new antibiotic class. PMID:22437830

Selective inhibition of biotin protein ligase from Staphylococcus aureus.

PubMed

Soares da Costa, Tatiana P; Tieu, William; Yap, Min Y; Pendini, Nicole R; Polyak, Steven W; Sejer Pedersen, Daniel; Morona, Renato; Turnidge, John D; Wallace, John C; Wilce, Matthew C J; Booker, Grant W; Abell, Andrew D

2012-05-18

There is a well documented need to replenish the antibiotic pipeline with new agents to combat the rise of drug resistant bacteria. One strategy to combat resistance is to discover new chemical classes immune to current resistance mechanisms that inhibit essential metabolic enzymes. Many of the obvious drug targets that have no homologous isozyme in the human host have now been investigated. Bacterial drug targets that have a closely related human homologue represent a new frontier in antibiotic discovery. However, to avoid potential toxicity to the host, these inhibitors must have very high selectivity for the bacterial enzyme over the human homolog. We have demonstrated that the essential enzyme biotin protein ligase (BPL) from the clinically important pathogen Staphylococcus aureus could be selectively inhibited. Linking biotin to adenosine via a 1,2,3 triazole yielded the first BPL inhibitor selective for S. aureus BPL over the human equivalent. The synthesis of new biotin 1,2,3-triazole analogues using click chemistry yielded our most potent structure (K(i) 90 nM) with a >1100-fold selectivity for the S. aureus BPL over the human homologue. X-ray crystallography confirmed the mechanism of inhibitor binding. Importantly, the inhibitor showed cytotoxicity against S. aureus but not cultured mammalian cells. The biotin 1,2,3-triazole provides a novel pharmacophore for future medicinal chemistry programs to develop this new antibiotic class.

A rapid method for selecting suitable animal species for studying pathogen interactions with plasma protein ligands in vivo.

PubMed

Naudin, Clément; Schumski, Ariane; Salo-Ahen, Outi M H; Herwald, Heiko; Smeds, Emanuel

2017-05-01

Species tropism constitutes a serious problem for developing relevant animal models of infection. Human pathogens can express virulence factors that show specific selectivity to human proteins, while their affinity for orthologs from other species can vary significantly. Suitable animal species must be used to analyse whether virulence factors are potential targets for drug development. We developed an assay that rapidly predicts applicable animal species for studying virulence factors binding plasma proteins. We used two well-characterized Staphylococcus aureus proteins, SSL7 and Efb, to develop an ELISA-based inhibition assay using plasma from different animal species. The interaction between SSL7 and human C5 and the binding of Efb to human fibrinogen and human C3 was studied. Affinity experiments and Western blot analyses were used to validate the assay. Human, monkey and cat plasma interfered with binding of SSL7 to human C5. Binding of Efb to human fibrinogen was blocked in human, monkey, gerbil and pig plasma, while human, monkey, gerbil, rabbit, cat and guinea pig plasma inhibited the binding of Efb to human C3. These results emphasize the importance of choosing correct animal models, and thus, our approach is a rapid and cost-effective method that can be used to prevent unnecessary animal experiments. © 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Staphylococcus aureus requires less virulence to establish an infection in diabetic hosts.

PubMed

Tuchscherr, Lorena; Korpos, Èva; van de Vyver, Hélène; Findeisen, Clais; Kherkheulidze, Salome; Siegmund, Anke; Deinhardt-Emmer, Stefanie; Bach, Olaf; Rindert, Martin; Mellmann, Alexander; Sunderkötter, Cord; Peters, Georg; Sorokin, Lydia; Löffler, Bettina

2018-05-22

Staphylococcus aureus is the most frequent pathogen causing diabetic foot infections. Here, we investigated the degree of bacterial virulence required to establish invasive tissue infections in diabetic organisms. Staphylococcal isolates from diabetic and non-diabetic foot ulcers were tested for their virulence in in vitro functional assays of host cell invasion and cytotoxicity. Isolates from diabetes mellitus type I/II patients exhibited less virulence than isolates from non-diabetic patients, but were nevertheless able to establish severe infections. In some cases, non-invasive isolates were detected deep within diabetic wounds, even though the strains were non-pathogenic in cell culture models. Testing of defined isolates in murine footpad injection models revealed that both low- and high-virulent bacterial strains persisted in higher numbers in diabetic compared to non-diabetic hosts, suggesting that hyperglycemia favors bacterial survival. Additionally, the bacterial load was higher in NOD mice, which have a compromised immune system, compared to C57Bl/6 mice. Our results reveal that high as well as low-virulent staphylococcal strains are able to cause soft tissue infections and to persist in diabetic humans and mice, suggesting a reason for the frequent and endangering infections in patients with diabetes. Copyright © 2018 Elsevier GmbH. All rights reserved.

Development and validation of a loop mediated isothermal amplification (LAMP) assay for the detection of Staphylococcus aureus in bovine mastitis milk samples.

PubMed

Sheet, O H; Grabowski, N T; Klein, G; Abdulmawjood, A

2016-10-01

Staphylococcus (S.) aureus is one of the most important animal pathogens causing bovine mastitis. Also, it is a major human pathogen that may produce a variety of toxins which cause staphylococcal food poisoning. In the present study a LAMP assay based on gene nuc to identify S. aureus was developed and validated. The specificity of the LAMP assay was confirmed by using 70 S. aureus isolates and 21 non-S. aureus strains. The optimal temperature-time combination to amplify gene nuc successfully was 65 °C and 30 min. The analytical sensitivity of the developed LAMP assay was 0.26 pg of S. aureus DNA per reaction. The limit of detection evaluated with milk spiked with S. aureus was 9 × 10 2  CFU mL -1 . The final results of this assay were available within less than 2 h. The present study showed that the LAMP assay based on gene nuc appeared to be rapid and simple, and could also be used to identify S. aureus isolates from mastitis milk of dairy cows. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cell differentiation defines acute and chronic infection cell types in Staphylococcus aureus.

PubMed

García-Betancur, Juan-Carlos; Goñi-Moreno, Angel; Horger, Thomas; Schott, Melanie; Sharan, Malvika; Eikmeier, Julian; Wohlmuth, Barbara; Zernecke, Alma; Ohlsen, Knut; Kuttler, Christina; Lopez, Daniel

2017-09-12

A central question to biology is how pathogenic bacteria initiate acute or chronic infections. Here we describe a genetic program for cell-fate decision in the opportunistic human pathogen Staphylococcus aureus , which generates the phenotypic bifurcation of the cells into two genetically identical but different cell types during the course of an infection. Whereas one cell type promotes the formation of biofilms that contribute to chronic infections, the second type is planktonic and produces the toxins that contribute to acute bacteremia. We identified a bimodal switch in the agr quorum sensing system that antagonistically regulates the differentiation of these two physiologically distinct cell types. We found that extracellular signals affect the behavior of the agr bimodal switch and modify the size of the specialized subpopulations in specific colonization niches. For instance, magnesium-enriched colonization niches causes magnesium binding to S. aureus teichoic acids and increases bacterial cell wall rigidity. This signal triggers a genetic program that ultimately downregulates the agr bimodal switch. Colonization niches with different magnesium concentrations influence the bimodal system activity, which defines a distinct ratio between these subpopulations; this in turn leads to distinct infection outcomes in vitro and in an in vivo murine infection model. Cell differentiation generates physiological heterogeneity in clonal bacterial infections and helps to determine the distinct infection types.

Cell differentiation defines acute and chronic infection cell types in Staphylococcus aureus

PubMed Central

García-Betancur, Juan-Carlos; Goñi-Moreno, Angel; Horger, Thomas; Schott, Melanie; Sharan, Malvika; Eikmeier, Julian; Wohlmuth, Barbara; Zernecke, Alma; Ohlsen, Knut; Kuttler, Christina

2017-01-01

A central question to biology is how pathogenic bacteria initiate acute or chronic infections. Here we describe a genetic program for cell-fate decision in the opportunistic human pathogen Staphylococcus aureus, which generates the phenotypic bifurcation of the cells into two genetically identical but different cell types during the course of an infection. Whereas one cell type promotes the formation of biofilms that contribute to chronic infections, the second type is planktonic and produces the toxins that contribute to acute bacteremia. We identified a bimodal switch in the agr quorum sensing system that antagonistically regulates the differentiation of these two physiologically distinct cell types. We found that extracellular signals affect the behavior of the agr bimodal switch and modify the size of the specialized subpopulations in specific colonization niches. For instance, magnesium-enriched colonization niches causes magnesium binding to S. aureusteichoic acids and increases bacterial cell wall rigidity. This signal triggers a genetic program that ultimately downregulates the agr bimodal switch. Colonization niches with different magnesium concentrations influence the bimodal system activity, which defines a distinct ratio between these subpopulations; this in turn leads to distinct infection outcomes in vitro and in an in vivo murine infection model. Cell differentiation generates physiological heterogeneity in clonal bacterial infections and helps to determine the distinct infection types. PMID:28893374

Transformation of Human Cathelicidin LL-37 into Selective, Stable, and Potent Antimicrobial Compounds

PubMed Central

2015-01-01

This Letter reports a family of novel antimicrobial compounds obtained by combining peptide library screening with structure-based design. Library screening led to the identification of a human LL-37 peptide resistant to chymotrypsin. This d-amino-acid-containing peptide template was active against Escherichia coli but not methicillin-resistant Staphylococcus aureus (MRSA). It possesses a unique nonclassic amphipathic structure with hydrophobic defects. By repairing the hydrophobic defects, the peptide (17BIPHE2) gained activity against the ESKAPE pathogens, including Enterococcus faecium, S. aureus, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa, and Enterobacter species. In vitro, 17BIPHE2 could disrupt bacterial membranes and bind to DNA. In vivo, the peptide prevented staphylococcal biofilm formation in a mouse model of catheter-associated infection. Meanwhile, it boosted the innate immune response to further combat the infection. Because these peptides are potent, cell-selective, and stable to several proteases, they may be utilized to combat one or more ESKAPE pathogens. PMID:25061850

Survival of human pathogenic bacteria in different types of natural mineral water.

PubMed

Serrano, Concepción; Romero, Margarita; Alou, Luis; Sevillano, David; Corvillo, Iluminada; Armijo, Francisco; Maraver, Francisco

2012-09-01

The aim of this study was to determine the survival of human pathogens (Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa) in five natural mineral waters (NMWs) with different properties and mineralization levels. Five NMWs from four Spanish spas with different dry residue at 110 °C were used: A = 76,935 mg/L; B = 1,827 mg/L; C = 808.4 mg/L; D = 283.8 mg/L; and E = 170.4 mg/L. An initial inoculum of 1 × 10(6) colony forming units (cfu)/mL was used for survival studies. Distilled water, chlorinated tap water and Mueller-Hinton broth were used as controls. Colony counts in all different waters were lower than those achieved with Mueller-Hinton broth over all incubation periods. A direct effect between the bacterial survival and the level of mineralization water was observed. The NMW E with low mineralization level along with the radioactive properties showed the highest antibacterial activity among all NMWs.

Concentration of airborne Staphylococcus aureus (MRSA and MSSA), total bacteria, and endotoxins in pig farms.

PubMed

Masclaux, Frederic G; Sakwinska, Olga; Charrière, Nicole; Semaani, Eulalia; Oppliger, Anne

2013-06-01

Pigs are very often colonized by Staphylococcus aureus and transmission of such pig-associated S. aureus to humans can cause serious medical, hygiene, and economic problems. The transmission route of zoonotic pathogens colonizing farm animals to humans is not well established and bioaerosols could play an important role. The aim of this study was to assess the potential occupational risk of working with S. aureus-colonized pigs in Switzerland. We estimated the airborne contamination by S. aureus in 37 pig farms (20 nursery and 17 fattening units; 25 in summer, 12 in winter). Quantification of total airborne bacterial DNA, airborne Staphylococcus sp. DNA, fungi, and airborne endotoxins was also performed. In this experiment, the presence of cultivable airborne methicillin-resistant S. aureus (MRSA) CC398 in a pig farm in Switzerland was reported for the first time. Airborne methicillin-sensitive S. aureus (MSSA) was found in ~30% of farms. The average airborne concentration of DNA copy number of total bacteria and Staphylococcus sp. measured by quantitative polymerase chain reaction was very high, respectively reaching values of 75 (± 28) × 10(7) and 35 (± 9.8) × 10(5) copy numbers m(-3) in summer and 96 (± 19) × 10(8) and 40 (± 12) × 10(6) copy numbers m(-3) in winter. Total mean airborne concentrations of endotoxins (1298 units of endotoxin m(-3)) and fungi (5707 colony-forming units m(-3)) exceeded the Swiss recommended values and were higher in winter than in summer. In conclusion, Swiss pig farmers will have to tackle a new emerging occupational risk, which could also have a strong impact on public health. The need to inform pig farmers about biological occupational risks is therefore crucial.

Presence of environmental coagulase-positive staphylococci, their clonal relationship, resistance factors and ability to form biofilm.

PubMed

Velázquez-Guadarrama, Norma; Olivares-Cervantes, Alma L; Salinas, Eva; Martínez, Leticia; Escorcia, Magdalena; Oropeza, Ricardo; Rosas, Irma

Coagulase-positive staphylococci (CoPS) are opportunistic pathogens carrying various mechanisms of resistance that have a large number of virulence factors, and whose ability to induce illness is associated with the host. This study aimed to investigate the presence of environmental coagulase-positive staphylococci, their susceptibility profile, clonal relationship and ability to form biofilm. The 16S rRNA genes from CoPS isolates were analyzed, and their antibiotic susceptibility was evaluated using the agar dilution method in accordance with Clinical and Laboratory Standards Institute guidelines. The clonal profile was obtained by pulsed-field gel electrophoresis (PFGE) and biofilm formation was measured by a crystal violet retention assay. A total of 72 Staphylococcus spp. strains were isolated from air, metal surfaces, and nostrils from humans, dogs, cats, and birds. Three species were identified: Staphylococcus aureus (17%), Staphylococcus intermedius (63%), and Staphylococcus pseudintermedius (21%). Ninety three percent (93%) of the strains were resistant to at least one of 13 tested antibiotics. S. pseudintermedius strains were the only resistant ones to methicillin while most of these isolates were multidrug-resistant, had significantly higher ability to form biofilm and PFGE grouped into seven different patterns, without showing clonal dispersion among animals and environmental isolates. This study suggests that dogs, cat, and air are environmental sources potentially carrying multidrug-resistant S. pseudintermedius, which survives in different environments through biofilm formation and multidrug resistance, characteristics that can be transmitted horizontally to other bacteria and exacerbate the problem of antibiotic resistance in humans. Copyright © 2016 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

Pathogenic bacteria carried by companion animals and their susceptibility to antibacterial agents.

PubMed

Buma, Ryoko; Maeda, Takuya; Kamei, Masaharu; Kourai, Hiroki

2006-03-01

Results of the investigation showed that there was a difference in the bacteria isolated from dogs, cats and their living environment. The number and species isolated from the hair and front paw samples from dogs kept outdoors and from cats were greater and more varied than those from the samples from dogs kept indoors. Staphylococcus, Micrococcus and Bacillus were frequently detected from skin surfaces. On the other hand, Escherichia, Pseudomonas, Proteus and others were detected on each sampling area on dogs kept outdoors and on cats. About 60% of the bacteria commonly causes infectious diseases and carries a risk of food poisoning. Moreover, Pasteurella multocida, which causes pasteurellasis, a kind of zoonosis, was isolated from dogs and cats. These pathogenic bacteria were transmitted from animals to humans by direct contact. This result suggests that direct contact with dogs and cats and contact with aerosols can possibly transmit infectious diseases. Most of the isolates (75.9%, 60/79) were resistant to antibacterial agents. We then investigated the effect of household detergents and pet care deodorant sprays containing antibacterial agents on isolates from dogs and cats. They were effective in preventing the transmission of pathogens from dogs and cats to humans.

Lipolytic activity of Staphylococcus aureus from human wounds, animals, foods, and food-contact surfaces in Brazil.

PubMed

dos Santos Rodrigues, Jessica Bezerra; Pinto, Taiz Siqueira; de Oliveira, Cybelle Pereira; de Sousa Freitas, Francisca Inês; Vieira Pereira, Maria do Socorro; de Souza, Evandro Leite; de Siqueria-Júnior, Jose Pinto

2014-08-13

S. aureus is of great importance to public health due to its pathogenicity. This study aimed to evaluate lipase production by S. aureus isolates from different sources. Lipolytic activity was determined using Tween-Calcium agar (48 hours; 35°C). Eighty-six percent of the isolates from human wounds were positive for lipase production. The frequencies of isolates positive for lipase production were 33.3% from cow udders, 15.4% from the nasal cavities of cattle, 82.9% from ricotta cheeses, and 100% and 91.7% from meat- and vegetable-contact surfaces, respectively. The production of lipase varied among the isolates according to their source.

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

PubMed

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

2015-05-01

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

Topical Antimicrobial Treatments Can Elicit Shifts to Resident Skin Bacterial Communities and Reduce Colonization by Staphylococcus aureus Competitors

PubMed Central

SanMiguel, Adam J.; Meisel, Jacquelyn S.; Horwinski, Joseph; Zheng, Qi

2017-01-01

ABSTRACT The skin microbiome is a complex ecosystem with important implications for cutaneous health and disease. Topical antibiotics and antiseptics are often employed to preserve the balance of this population and inhibit colonization by more pathogenic bacteria. However, despite their widespread use, the impact of these interventions on broader microbial communities remains poorly understood. Here, we report the longitudinal effects of topical antibiotics and antiseptics on skin bacterial communities and their role in Staphylococcus aureus colonization resistance. In response to antibiotics, cutaneous populations exhibited an immediate shift in bacterial residents, an effect that persisted for multiple days posttreatment. By contrast, antiseptics elicited only minor changes to skin bacterial populations, with few changes to the underlying microbiota. While variable in scope, both antibiotics and antiseptics were found to decrease colonization by commensal Staphylococcus spp. by sequencing- and culture-based methods, an effect which was highly dependent on baseline levels of Staphylococcus. Because Staphylococcus residents have been shown to compete with the skin pathogen S. aureus, we also tested whether treatment could influence S. aureus levels at the skin surface. We found that treated mice were more susceptible to exogenous association with S. aureus and that precolonization with the same Staphylococcus residents that were previously disrupted by treatment reduced S. aureus levels by over 100-fold. In all, the results of this study indicate that antimicrobial drugs can alter skin bacterial residents and that these alterations can have critical implications for cutaneous host defense. PMID:28630195

Commensal coagulase-negative Staphylococcus from the udder of healthy cows inhibits biofilm formation of mastitis-related pathogens.

PubMed

Isaac, Paula; Bohl, Luciana Paola; Breser, María Laura; Orellano, María Soledad; Conesa, Agustín; Ferrero, Marcela Alejandra; Porporatto, Carina

2017-08-01

Bovine mastitis, considered the most important cause of economic losses in the dairy industry, is a major concern in veterinary medicine. Staphylococcus aureus and coagulase-negative staphylococci (CNS) are the main pathogens associated with intramammary infections, and bacterial biofilms are suspected to be responsible for the persistence of this disease. CNS from the udder are not necessarily associated with intramammary infections. In fact, some commensal CNS have been shown to have biological activities. This issue led us to screen exoproducts from commensal Staphylococcus chromogenes for anti-biofilm activity against different mastitis pathogens. The cell-free supernatant from S. chromogenes LN1 (LN1-CFS) was confirmed to display a non-biocidal inhibition of pathogenic biofilms. The supernatant was subjected to various treatments to estimate the nature of the biofilm-inhibiting compounds. The results showed that the bioactive compound >5KDa in mass is sensitive to thermal treatment and proteinase K digestion, suggesting its protein properties. LN1-CFS was able to significantly inhibit S. aureus and CNS biofilm formation in a dose-independent manner and without affecting the viability of bovine cells. These findings reveal a new activity of the udder microflora of healthy animals. Studies are underway to purify and identify the anti-biofilm biocompound and to evaluate its biological activity in vivo. Copyright © 2017 Elsevier B.V. All rights reserved.

Microstructures as IR-sensors with Staphylococcus aureus bacteria

NASA Astrophysics Data System (ADS)

Baikova, T. V.; Danilov, P. A.; Gonchukov, S. A.; Yermachenko, V. M.; Ionin, A. A.; Khmelnitskii, R. A.; Kudryashov, S. I.; Nguyen, T. T. H.; Rudenko, A. A.; Saraeva, I. N.; Svistunova, T. S.; Zayarny, D. A.

2017-09-01

Using a micro-hole grating in a supported silver film as a laser-fabricated novel optical platform for surface-enhanced IR absoprtion/reflection spectroscopy, characteristic absorption bands of Staphylococcus aureus, especially - its buried carotenoid fragments - were detected in FT-IR spectra with 10-fold analytical enhancement, paving the way to spectral express-identification of the pathogenic microorganisms.

Structure of the Anthrax Research Literature

DTIC Science & Technology

2006-01-01

4; identification 4; staphylococcus - aureus 3; pharmacology & pharmacy 3; microbiology 3; pharmacology & pharmacy 2; biotechnology & applied...proteins 4; microbiology 4; escherichia-coli 4; bacillus-anthracis 4; cell-wall 3; staphylococcus - aureus 3 Country usa 9; france 7; england 2...pathogen detection using a microchip PCR array Instrument 199 In vitro selection of DNA aptamers to anthrax spores with electrochemiluminescence

Genome Sequences of Four Staphylococcus aureus Strains Isolated from Bovine Mastitis

PubMed Central

Taponen, Suvi; Koort, Joanna; Paulin, Lars; Åvall-Jääskeläinen, Silja

2015-01-01

Staphylococcus aureus is a major causative agent of mastitis in dairy cows. The pathogenicity of S. aureus may vary; it is able to cause severe clinical mastitis, but most often it is associated with chronic subclinical mastitis. Here, we present the genome assemblies of four S. aureus strains from bovine mastitis. PMID:25908141

Identification and characterization of peptidoglycan hydrolase constructs with activity in cow milk as potential antimicrobials for treatment of staphylococcal bovine mastitis

USDA-ARS?s Scientific Manuscript database

Mastitis in dairy cows is a widespread infection of the mammary glands that leads to high losses in dairy production. Most members of the Gram-positive genus Staphylococcus can cause mastitis, with Staphylococcus S. aureus being one of the major pathogens. Intramammary application of antibiotics i...

Rapid detection and differentiation of Staphylococcus colonies using an optical scattering technology.

PubMed

Alsulami, Tawfiq S; Zhu, Xingyue; Abdelhaseib, Maha Usama; Singh, Atul K; Bhunia, Arun K

2018-05-24

Staphylococcus species are a major pathogen responsible for nosocomial infections and foodborne illnesses. We applied a laser-based BARDOT (bacterial rapid detection using optical scattering technology) for rapid colony screening and detection of Staphylococcus on an agar plate and differentiate these from non-Staphylococcus spp. Among the six growth media tested, phenol red mannitol agar (PRMA) was found most suitable for building the Staphylococcus species scatter image libraries. Scatter image library for Staphylococcus species gave a high positive predictive value (PPV 87.5-100%) when tested against known laboratory strains of Staphylococcus spp., while the PPV against non-Staphylococcus spp. was 0-38%. A total of nine naturally contaminated bovine raw milk and ready-to-eat chicken salad samples were tested, and BARDOT detected Staphylococcus including Staphylococcus aureus with 80-100% PPV. Forty-five BARDOT-identified bacterial isolates from naturally contaminated foods were further confirmed by tuf and nuc gene-specific PCR and 16S rRNA gene sequence. This label-free, non-invasive on-plate colony screening technology can be adopted by the food industries, biotechnology companies, and public health laboratories for Staphylococcus species detection including S. aureus from various samples for food safety and public health management. Graphical abstract.

Evaluation of high-resolution melting curve analysis of ligation-mediated real-time PCR, a rapid method for epidemiological typing of ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter Species) pathogens.

PubMed

Woksepp, Hanna; Ryberg, Anna; Billström, Hanna; Hällgren, Anita; Nilsson, Lennart E; Marklund, Britt-Inger; Olsson-Liljequist, Barbro; Schön, Thomas

2014-12-01

A single-tube method, ligation-mediated real-time PCR high-resolution melt analysis (LMqPCR HRMA), was modified for the rapid typing of Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp. (ESKAPE) pathogens. A 97% agreement (60/62 isolates) was achieved in comparison to pulsed-field gel electrophoresis (PFGE) results, which indicates that LMqPCR HRMA is a rapid and accurate screening tool for monitoring nosocomial outbreaks. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Genome Analysis of Staphylococcus agnetis, an Agent of Lameness in Broiler Chickens

PubMed Central

Ojha, Sohita; Pummill, Jeff F.; Koon, Joseph A.; Wideman, Robert F.; Rhoads, Douglas D.

2015-01-01

Lameness in broiler chickens is a significant animal welfare and financial issue. Lameness can be enhanced by rearing young broilers on wire flooring. We have identified Staphylococcus agnetis as significantly involved in bacterial chondronecrosis with osteomyelitis (BCO) in proximal tibia and femorae, leading to lameness in broiler chickens in the wire floor system. Administration of S. agnetis in water induces lameness. Previously reported in some cases of cattle mastitis, this is the first report of this poorly described pathogen in chickens. We used long and short read next generation sequencing to assemble single finished contigs for the genome and a large plasmid from the chicken pathogen. Comparison of the S. agnetis genome to those of other pathogenic Staphylococci shows that S.agnetis contains a distinct repertoire of virulence determinants. Additionally, the S. agnetis genome has several regions that differ substantially from the genomes of other pathogenic Staphylococci. Comparison of our finished genome to a recent draft genome for a cattle mastitis isolate suggests that future investigations focus on the evolutionary epidemiology of this emerging pathogen of domestic animals. PMID:26606420

Eliciting antibiotics active against the ESKAPE pathogens in a collection of actinomycetes isolated from mountain soils.

PubMed

Zhu, Hua; Swierstra, Jasper; Wu, Changsheng; Girard, Geneviève; Choi, Young Hae; van Wamel, Willem; Sandiford, Stephanie K; van Wezel, Gilles P

2014-08-01

The rapid emergence of multidrug-resistant (MDR) bacterial pathogens poses a major threat for human health. In recent years, genome sequencing has unveiled many poorly expressed antibiotic clusters in actinomycetes. Here, we report a well-defined ecological collection of >800 actinomycetes obtained from sites in the Himalaya and Qinling mountains, and we used these in a concept study to see how efficiently antibiotics can be elicited against MDR pathogens isolated recently from the clinic. Using 40 different growth conditions, 96 actinomycetes were identified - predominantly Streptomyces - that produced antibiotics with efficacy against the MDR clinical isolates referred to as ESKAPE pathogens: Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and/or Enterobacter cloacae. Antimicrobial activities that fluctuated strongly with growth conditions were correlated with specific compounds, including borrelidin, resistomycin, carbomethoxy-phenazine, and 6,7,8- and 5,6,8-trimethoxy-3-methylisocoumarin, of which the latter was not described previously. Our work provided insights into the potential of actinomycetes as producers of drugs with efficacy against clinical isolates that have emerged recently and also underlined the importance of targeting a specific pathogen. © 2014 The Authors.

Staphylococcus spp., Streptococcus canis, and Arcanobacterium phocae of healthy Canadian farmed mink and mink with pododermatitis.

PubMed

Chalmers, Gabhan; McLean, John; Hunter, D Bruce; Brash, Marina; Slavic, Durda; Pearl, David L; Boerlin, Patrick

2015-04-01

Pododermatitis is a disease of concern for mink breeders in Canada and worldwide, as it causes discomfort and lowers the breeding rates on farms affected by the disease. Unfortunately, the etiology and pathogenesis of pododermatitis are still unknown. In this study, we compared Staphylococcus spp. and Streptococcus canis isolates from healthy mink with isolates from animals with pododermatitis on 2 farms in Ontario. Almost all hemolytic Staphylococcus spp. isolated were shown to be Staphylococcus delphini Group A by 16S ribosomal ribonucleic acid (rRNA) sequence analysis and polymerase chain reaction (PCR). Pulsed-field gel electrophoresis (PFGE) did not reveal any S. delphini or S. canis clonal lineages specifically associated with pododermatitis, which suggests that these bacteria do not act as primary pathogens, but does not dismiss their potential roles as opportunistic pathogens. While S. delphini and S. canis were the most prevalent bacterial pathogens in mink pododermatitis, they were also present in samples from healthy mink. Arcanobacterium phocae is occasionally isolated from pododermatitis cases, but is difficult to recover with conventional culture methods due to its slow growth. A quantitative real-time PCR was developed for the detection of A. phocae and was tested on 138 samples of footpad tissues from 14 farms. The bacterium was detected only in pododermatitis-endemic farms in Canada and was at higher concentrations in tissues from infected footpads than in healthy tissues. This finding suggests that A. phocae is involved in the pathogenesis of pododermatitis.

Staphylococcus spp., Streptococcus canis, and Arcanobacterium phocae of healthy Canadian farmed mink and mink with pododermatitis

PubMed Central

Chalmers, Gabhan; McLean, John; Hunter, D. Bruce; Brash, Marina; Slavic, Durda; Pearl, David L.; Boerlin, Patrick

2015-01-01

Pododermatitis is a disease of concern for mink breeders in Canada and worldwide, as it causes discomfort and lowers the breeding rates on farms affected by the disease. Unfortunately, the etiology and pathogenesis of pododermatitis are still unknown. In this study, we compared Staphylococcus spp. and Streptococcus canis isolates from healthy mink with isolates from animals with pododermatitis on 2 farms in Ontario. Almost all hemolytic Staphylococcus spp. isolated were shown to be Staphylococcus delphini Group A by 16S ribosomal ribonucleic acid (rRNA) sequence analysis and polymerase chain reaction (PCR). Pulsed-field gel electrophoresis (PFGE) did not reveal any S. delphini or S. canis clonal lineages specifically associated with pododermatitis, which suggests that these bacteria do not act as primary pathogens, but does not dismiss their potential roles as opportunistic pathogens. While S. delphini and S. canis were the most prevalent bacterial pathogens in mink pododermatitis, they were also present in samples from healthy mink. Arcanobacterium phocae is occasionally isolated from pododermatitis cases, but is difficult to recover with conventional culture methods due to its slow growth. A quantitative real-time PCR was developed for the detection of A. phocae and was tested on 138 samples of footpad tissues from 14 farms. The bacterium was detected only in pododermatitis-endemic farms in Canada and was at higher concentrations in tissues from infected footpads than in healthy tissues. This finding suggests that A. phocae is involved in the pathogenesis of pododermatitis. PMID:25852228

Ventilator-associated pneumonia caused by ESKAPE organisms: cause, clinical features, and management.

PubMed

Sandiumenge, Alberto; Rello, Jordi

2012-05-01

Despite important geographical variations, Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter species (ESKAPE) pathogens constitute more than 80% of ventilator-associated pneumonia (VAP) episodes. Their clinical importance relies on their virulence and ability in developing mechanisms to decrease susceptibility to antimicrobials, increasing inappropriate therapy and affecting negatively on ICU patients' outcome. This review updates information on VAP due to ESKAPE pathogens. Although methicillin-resistant Staphylococcus aureus VAP may be clinically similar to that caused by susceptible strains, it is associated with poorer outcomes despite adequate treatment. Local colonization determines treatment options. The contribution of tracheobronchitis is an important issue. Minimum inhibitory concentration should be considered for nonfermentative Gram-negative bacteria VAP to prescribe extended infusion β-lactam treatment due to an increase of resistant strains. Strategies promoting antimicrobial diversity may protect against emergence and spread of resistance by ESKAPE pathogens. VAP due to ESKAPE pathogens represents a global challenge that can be prevented using stewardship programmes promoting diversity.

In vitro bactericidal activity of 465-470 nm blue light phototherapy and aminolevulinic acid on Staphylococcus pseudintermedius.

PubMed

Bae, Seulgi; Oh, Taeho

2018-05-30

Staphylococcus pseudintermedius is the principal pathogen causing bacterial skin infections in dogs. Photodynamic therapy (PDT) involving the combination of light and a topical photosensitizer is used to treat human skin infections. Although the antimicrobial effects of PDT have been demonstrated using in vivo and in vitro studies in humans, its effects on dogs and their pathogens are unclear. The aim of this study was to demonstrate the in vitro efficacy of PDT over a 465-470 nm spectrum to kill S. pseudintermedius using δ-aminolevulinic acid (ALA) as the photosensitizer. Six S. pseudintermedius isolates from canine skin were exposed to blue light-emitting diodes (LEDs) at 465-470 nm, with or without ALA. The light doses were 18.4, 36.8 and 55.2 J/cm 2 . The number of colony-forming units and optical densities of broth cultures were measured and then compared with Dunnett's test. Bacterial viability was monitored using fluorescence microscopy and the fluorescence intensity values were compared with a paired Student's t-test. Blue light inhibited the growth of S. pseudintermedius; the effect significantly increased with the addition of ALA as a photosensitizer and with increasing light doses. Live/dead staining confirmed that PDT reduced bacterial viability and exerted an antibacterial effect. Blue light has a strong antibacterial effect on S. pseudintermedius in a light dose-dependent manner. ALA alone did not exhibit bactericidal action, but its combination with blue light increased the effect of PDT compared to blue light alone. © 2018 ESVD and ACVD.

Broad-range lytic bacteriophages that kill Staphylococcus aureus local field strains

PubMed Central

Boncompain, Carina A.; Amadio, Ariel A.; Carrasco, Soledad; Suárez, Cristian A.

2017-01-01

Staphylococcus aureus is a very successful opportunistic pathogen capable of causing a variety of diseases ranging from mild skin infections to life-threatening sepsis, meningitis and pneumonia. Its ability to display numerous virulence mechanisms matches its skill to display resistance to several antibiotics, including β-lactams, underscoring the fact that new anti-S. aureus drugs are urgently required. In this scenario, the utilization of lytic bacteriophages that kill bacteria in a genus -or even species- specific way, has become an attractive field of study. In this report, we describe the isolation, characterization and sequencing of phages capable of killing S. aureus including methicillin resistant (MRSA) and multi-drug resistant S. aureus local strains from environmental, animal and human origin. Genome sequencing and bio-informatics analysis showed the absence of genes encoding virulence factors, toxins or antibiotic resistance determinants. Of note, there was a high similarity between our set of phages to others described in the literature such as phage K. Considering that reported phages were obtained in different continents, it seems plausible that there is a commonality of genetic features that are needed for optimum, broad host range anti-staphylococcal activity of these related phages. Importantly, the high activity and broad host range of one of our phages underscores its promising value to control the presence of S. aureus in fomites, industry and hospital environments and eventually on animal and human skin. The development of a cocktail of the reported lytic phages active against S. aureus–currently under way- is thus, a sensible strategy against this pathogen. PMID:28742812

Broad-range lytic bacteriophages that kill Staphylococcus aureus local field strains.

PubMed

Abatángelo, Virginia; Peressutti Bacci, Natalia; Boncompain, Carina A; Amadio, Ariel F; Carrasco, Soledad; Suárez, Cristian A; Morbidoni, Héctor R

2017-01-01

Staphylococcus aureus is a very successful opportunistic pathogen capable of causing a variety of diseases ranging from mild skin infections to life-threatening sepsis, meningitis and pneumonia. Its ability to display numerous virulence mechanisms matches its skill to display resistance to several antibiotics, including β-lactams, underscoring the fact that new anti-S. aureus drugs are urgently required. In this scenario, the utilization of lytic bacteriophages that kill bacteria in a genus -or even species- specific way, has become an attractive field of study. In this report, we describe the isolation, characterization and sequencing of phages capable of killing S. aureus including methicillin resistant (MRSA) and multi-drug resistant S. aureus local strains from environmental, animal and human origin. Genome sequencing and bio-informatics analysis showed the absence of genes encoding virulence factors, toxins or antibiotic resistance determinants. Of note, there was a high similarity between our set of phages to others described in the literature such as phage K. Considering that reported phages were obtained in different continents, it seems plausible that there is a commonality of genetic features that are needed for optimum, broad host range anti-staphylococcal activity of these related phages. Importantly, the high activity and broad host range of one of our phages underscores its promising value to control the presence of S. aureus in fomites, industry and hospital environments and eventually on animal and human skin. The development of a cocktail of the reported lytic phages active against S. aureus-currently under way- is thus, a sensible strategy against this pathogen.

Antibiofilm activity of Vetiveria zizanioides root extract against methicillin-resistant Staphylococcus aureus.

PubMed

Kannappan, Arunachalam; Gowrishankar, Shanmugaraj; Srinivasan, Ramanathan; Pandian, Shunmugiah Karutha; Ravi, Arumugam Veera

2017-09-01

Methicillin-resistant Staphylococcus aureus (MRSA) is a leading human pathogen responsible for causing chronic clinical manifestation worldwide. In addition to antibiotic resistance genes viz. mecA and vanA, biofilm formation plays a prominent role in the pathogenicity of S. aureus by enhancing its resistance to existing antibiotics. Considering the role of folk medicinal plants in the betterment of human health from the waves of multidrug resistant bacterial infections, the present study was intended to explore the effect of Vetiveria zizanioides root on the biofilm formation of MRSA and its clinical counterparts. V. zizanioides root extract (VREX) showed a concentration-dependent reduction in biofilm formation without hampering the cellular viability of the tested strains. Micrographs of scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) portrayed the devastating impact of VREX on biofilm formation. In addition to antibiofilm activity, VREX suppresses the production of biofilm related phenotypes such as exopolysaccharide, slime and α-hemolysin toxin. Furthermore, variation in FT-IR spectra evidenced the difference in cellular factors of untreated and VREX treated samples. Result of mature biofilm disruption assay and down regulation of genes like fnbA, fnbB, clfA suggested that VREX targets these adhesin genes responsible for initial adherence. GC-MS analysis revealed the presence of sesquiterpenes as a major constituent in VREX. Thus, the data of present study strengthen the ethnobotanical value of V. zizanioides and concludes that VREX contain bioactive molecules that have beneficial effect over the biofilm formation of MRSA and its clinical isolates. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sensitization of Staphylococcus aureus to Methicillin and Other Antibiotics In Vitro and In Vivo in the Presence of HAMLET

PubMed Central

Marks, Laura R.; Clementi, Emily A.; Hakansson, Anders P.

2013-01-01

HAMLET (human alpha-lactalbumin made lethal to tumor cells) is a protein-lipid complex from human milk with both tumoricidal and bactericidal activities. HAMLET exerts a rather specific bactericidal activity against some respiratory pathogens, with highest activity against Streptococcus pneumoniae, but lacks activity against most other bacterial pathogens, including Staphylococci. Still, ion transport associated with death in S. pneumoniae is also detected to a lower degree in insensitive organisms. In this study we demonstrate that HAMLET acts as an antimicrobial adjuvant that can increase the activity of a broad spectrum of antibiotics (methicillin, vancomycin, gentamicin and erythromycin) against multi-drug resistant Staphylococcus aureus, to a degree where they become sensitive to those same antibiotics, both in antimicrobial assays against planktonic and biofilm bacteria and in an in vivo model of nasopharyngeal colonization. We show that HAMLET exerts these effects specifically by dissipating the proton gradient and inducing a sodium-dependent calcium influx that partially depolarizes the plasma membrane, the same mechanism induced during pneumococcal death. These effects results in an increased cell associated binding and/or uptake of penicillin, gentamicin and vancomycin, especially in resistant stains. Finally, HAMLET inhibits the increased resistance of methicillin seen under antibiotic pressure and the bacteria do not become resistant to the adjuvant, which is a major advantageous feature of the molecule. These results highlight HAMLET as a novel antimicrobial adjuvant with the potential to increase the clinical usefulness of antibiotics against drug resistant strains of S. aureus. PMID:23650551

Repurposing Clinical Molecule Ebselen to Combat Drug Resistant Pathogens.

PubMed

Thangamani, Shankar; Younis, Waleed; Seleem, Mohamed N

2015-01-01

Without a doubt, our current antimicrobials are losing the battle in the fight against newly-emerged multidrug-resistant pathogens. There is a pressing, unmet need for novel antimicrobials and novel approaches to develop them; however, it is becoming increasingly difficult and costly to develop new antimicrobials. One strategy to reduce the time and cost associated with antimicrobial innovation is drug repurposing, which is to find new applications outside the scope of the original medical indication of the drug. Ebselen, an organoselenium clinical molecule, possesses potent antimicrobial activity against clinical multidrug-resistant Gram-positive pathogens, including Staphylococcus, Streptococcus, and Enterococcus, but not against Gram-negative pathogens. Moreover, the activity of ebselen against Gram-positive pathogens exceeded those activities determined for vancomycin and linezolid, drugs of choice for treatment of Enterococcus and Staphylococcus infections. The minimum inhibitory concentrations of ebselen at which 90% of clinical isolates of Enterococcus and Staphylococcus were inhibited (MIC90) were found to be 0.5 and 0.25 mg/L, respectively. Ebselen showed significant clearance of intracellular methicillin-resistant S. aureus (MRSA) in comparison to vancomycin and linezolid. We demonstrated that ebselen inhibits the bacterial translation process without affecting mitochondrial biogenesis. Additionally, ebselen was found to exhibit excellent activity in vivo in a Caenorhabditis elegans MRSA-infected whole animal model. Finally, ebselen showed synergistic activities with conventional antimicrobials against MRSA. Taken together, our results demonstrate that ebselen, with its potent antimicrobial activity and safety profiles, can be potentially used to treat multidrug resistant Gram-positive bacterial infections alone or in combination with other antibiotics and should be further clinically evaluated.

Molecular and Culture-Based Assessment of the Microbial Diversity of Diabetic Chronic Foot Wounds and Contralateral Skin Sites

PubMed Central

Oates, Angela; Bowling, Frank L.; Boulton, Andrew J. M.

2012-01-01

Wound debridement samples and contralateral (healthy) skin swabs acquired from 26 patients attending a specialist foot clinic were analyzed by differential isolation and eubacterium-specific PCR-denaturing gradient gel electrophoresis (DGGE) in conjunction with DNA sequencing. Thirteen of 26 wounds harbored pathogens according to culture analyses, with Staphylococcus aureus being the most common (13/13). Candida (1/13), pseudomonas (1/13), and streptococcus (7/13) were less prevalent. Contralateral skin was associated with comparatively low densities of bacteria, and overt pathogens were not detected. According to DGGE analyses, all wounds contained significantly greater eubacterial diversity than contralateral skin (P < 0.05), although no significant difference in total eubacterial diversity was detected between wounds from which known pathogens had been isolated and those that were putatively uninfected. DGGE amplicons with homology to Staphylococcus sp. (8/13) and S. aureus (2/13) were detected in putatively infected wound samples, while Staphylococcus sp. amplicons were detected in 11/13 noninfected wounds; S. aureus was not detected in these samples. While a majority of skin-derived DGGE consortial fingerprints could be differentiated from wound profiles through principal component analysis (PCA), a large minority could not. Furthermore, wounds from which pathogens had been isolated could not be distinguished from putatively uninfected wounds on this basis. In conclusion, while chronic wounds generally harbored greater eubacterial diversity than healthy skin, the isolation of known pathogens was not associated with qualitatively distinct consortial profiles or otherwise altered diversity. The data generated support the utility of both culture and DGGE for the microbial characterization of chronic wounds. PMID:22553231

Isolation and identification of local bacteria endophyte and screening of its antimicrobial property against pathogenic bacteria and fungi

NASA Astrophysics Data System (ADS)

Fikri, Ahmad Syairazie Ibrahim; Rahman, Irman Abdul; Nor, Norefrina Shafinaz Md; Hamzah, Ainon

2018-04-01

Endophytes are organisms, often fungi and bacteria that live in living plant cells. These organisms reside in the living tissues of the host plant in a variety of relationships, ranging from symbiotic to slightly pathogenic. The endophytes may produce a plethora of substances that have potential to be used in modern medicine, agriculture and industry. The aims of this study are to isolate, identify and screening antimicrobial activity of bacterial endophytes. The endophytes were isolated using nutrient agar, incubated at 37°C for 48 hours. Identification of the isolates were done based on morphological characteristics, biochemical tests and 16S rDNA molecular analysis. Disk diffusion method was used to screen for antimicrobial activity of metabolites from endophytes against pathogenic bacteria. Screening for antifungal activity of selected endophytes was done using dual culture method againts pathogenic fungi followed by Kirby-Bauer method. Results showed endophytes designated as B2c and B7b have positive antimicrobial activity. The metabolites from isolate B2c showed antimicrobial activity against pathogenic bacteria methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus aureus and Staphylococcus epidermis, while isolate B7b have positive activities againts MRSA, S. aureus and Pseudomonas aeruginosa. Isolates B2c displayed antifungal activity against Fusarium oxysporum, Fusarium solani, Phytophthora palmivora and Colletotrichum gloeosporioides. Identification using biochemical tests and 16S rDNA sequences identified isolate B2c as Pseudomonas resinovorans with 97% homology and isolate B7b as Bacillus subtilis with 98% homology.

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. Copyright © 2015 Elsevier B.V. All rights reserved.

Rational Design of Broad Spectrum Antibacterial Activity Based on a Clinically Relevant Enoyl-Acyl Carrier Protein (ACP) Reductase Inhibitor*

PubMed Central

Schiebel, Johannes; Chang, Andrew; Shah, Sonam; Lu, Yang; Liu, Li; Pan, Pan; Hirschbeck, Maria W.; Tareilus, Mona; Eltschkner, Sandra; Yu, Weixuan; Cummings, Jason E.; Knudson, Susan E.; Bommineni, Gopal R.; Walker, Stephen G.; Slayden, Richard A.; Sotriffer, Christoph A.; Tonge, Peter J.; Kisker, Caroline

2014-01-01

Determining the molecular basis for target selectivity is of particular importance in drug discovery. The ideal antibiotic should be active against a broad spectrum of pathogenic organisms with a minimal effect on human targets. CG400549, a Staphylococcus-specific 2-pyridone compound that inhibits the enoyl-acyl carrier protein reductase (FabI), has recently been shown to possess human efficacy for the treatment of methicillin-resistant Staphylococcus aureus infections, which constitute a serious threat to human health. In this study, we solved the structures of three different FabI homologues in complex with several pyridone inhibitors, including CG400549. Based on these structures, we rationalize the 65-fold reduced affinity of CG400549 toward Escherichia coli versus S. aureus FabI and implement concepts to improve the spectrum of antibacterial activity. The identification of different conformational states along the reaction coordinate of the enzymatic hydride transfer provides an elegant visual depiction of the relationship between catalysis and inhibition, which facilitates rational inhibitor design. Ultimately, we developed the novel 4-pyridone-based FabI inhibitor PT166 that retained favorable pharmacokinetics and efficacy in a mouse model of S. aureus infection with extended activity against Gram-negative and mycobacterial organisms. PMID:24739388

Methicillin resistant Staphylococcus aureus (MRSA) carriage in different free-living wild animal species in Spain.

PubMed

Porrero, M Concepción; Mentaberre, Gregorio; Sánchez, Sergio; Fernández-Llario, Pedro; Gómez-Barrero, Susana; Navarro-Gonzalez, Nora; Serrano, Emmanuel; Casas-Díaz, Encarna; Marco, Ignasi; Fernández-Garayzabal, José-Francisco; Mateos, Ana; Vidal, Dolors; Lavín, Santiago; Domínguez, Lucas

2013-10-01

Methicillin-resistant Staphylococcus aureus (MRSA) is a life-threatening pathogen in humans and its presence in animals is a public health concern. The aim of this study was to measure the prevalence of MRSA in free-living wild animals. Samples from red deer (n=273), Iberian ibex (n=212), Eurasian Griffon vulture (n=40) and wild boar (n=817) taken from different areas in Spain between June 2008 and November 2011 were analyzed. Characterization of the isolates was performed by spa typing, multi-locus sequence typing (MLST) and antimicrobial susceptibility testing. A low prevalence of MRSA was found with 13 isolates obtained from 12 animals (0.89%; 95% CI: 0.46-1.56). All MRSA sequence types belonged to ST398 (t011 and t1451) and ST1 (t127). Genotypes and antimicrobial susceptibility patterns (tetracycline resistance in ST398 and clindamycin-erythromycin-tetracycline resistance in ST1) suggest that the MRSA found probably originated in livestock (ST398) or humans (ST1). This is the first report of MRSA carriers in free-living wild animals in Europe. Although our data showed that MRSA prevalence is currently low, free-living wild animals might act as reservoir and represent a potential risk for human health. Copyright © 2013 Elsevier Ltd. All rights reserved.

Rational design of broad spectrum antibacterial activity based on a clinically relevant enoyl-acyl carrier protein (ACP) reductase inhibitor.

PubMed

Schiebel, Johannes; Chang, Andrew; Shah, Sonam; Lu, Yang; Liu, Li; Pan, Pan; Hirschbeck, Maria W; Tareilus, Mona; Eltschkner, Sandra; Yu, Weixuan; Cummings, Jason E; Knudson, Susan E; Bommineni, Gopal R; Walker, Stephen G; Slayden, Richard A; Sotriffer, Christoph A; Tonge, Peter J; Kisker, Caroline

2014-06-06

Determining the molecular basis for target selectivity is of particular importance in drug discovery. The ideal antibiotic should be active against a broad spectrum of pathogenic organisms with a minimal effect on human targets. CG400549, a Staphylococcus-specific 2-pyridone compound that inhibits the enoyl-acyl carrier protein reductase (FabI), has recently been shown to possess human efficacy for the treatment of methicillin-resistant Staphylococcus aureus infections, which constitute a serious threat to human health. In this study, we solved the structures of three different FabI homologues in complex with several pyridone inhibitors, including CG400549. Based on these structures, we rationalize the 65-fold reduced affinity of CG400549 toward Escherichia coli versus S. aureus FabI and implement concepts to improve the spectrum of antibacterial activity. The identification of different conformational states along the reaction coordinate of the enzymatic hydride transfer provides an elegant visual depiction of the relationship between catalysis and inhibition, which facilitates rational inhibitor design. Ultimately, we developed the novel 4-pyridone-based FabI inhibitor PT166 that retained favorable pharmacokinetics and efficacy in a mouse model of S. aureus infection with extended activity against Gram-negative and mycobacterial organisms. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

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

PubMed Central

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

2013-01-01

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

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

PubMed Central

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

2014-01-01

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

A novel cysteine-free venom peptide with strong antimicrobial activity against antibiotics-resistant pathogens from the scorpion Opistophthalmus glabrifrons.

PubMed

Bao, Aorigele; Zhong, Jie; Zeng, Xian-Chun; Nie, Yao; Zhang, Lei; Peng, Zhao Feng

2015-10-01

Antibiotic-resistant bacteria, such as methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus, pose serious threat to human health. The outbreak of antibiotic-resistant pathogens in recent years emphasizes once again the urgent need for the development of new antimicrobial agents. Here, we discovered a novel antimicrobial peptide from the scorpion Opistophthalmus glabrifrons, which was referred to as Opisin. Opisin consists of 19 amino acid residues without disulfide bridges. It is a cationic, amphipathic, and α-helical molecule. Protein sequence homology search revealed that Opisin shares 42.1-5.3% sequence identities to the 17/18-mer antimicrobial peptides from scorpions. Antimicrobial assay showed that Opisin is able to potently inhibit the growth of the tested Gram-positive bacteria with the minimal inhibitory concentration (MIC) values of 4.0-10.0 μM; in contrast, it possesses much lower activity against the tested Gram-negative bacteria and a fungus. It is interesting to see that Opisin is able to strongly inhibit the growth of methicillin- and vancomycin-resistant pathogens with the MICs ranging from 2.0 to 4.0 μM and from 4.0 to 6.0 μM, respectively. We found that at a concentration of 5 × MIC, Opisin completely killed all the cultured methicillin-resistant Staphylococcus aureus. These results suggest that Opisin is a promising therapeutic candidate for the treatment of the antibiotic-resistant bacterial infections. Copyright © 2015 European Peptide Society and John Wiley & Sons, Ltd.

Geographic setting influences Great Lakes beach microbiological water quality

USGS Publications Warehouse

Haack, Sheridan K.; Fogarty, Lisa R.; Stelzer, Erin A.; Fuller, Lori M.; Brennan, Angela K.; Isaacs, Natasha M.; Johnson, Heather E.

2013-01-01

Understanding of factors that influence Escherichia coli (EC) and enterococci (ENT) concentrations, pathogen occurrence, and microbial sources at Great Lakes beaches comes largely from individual beach studies. Using 12 representative beaches, we tested enrichment cultures from 273 beach water and 22 tributary samples for EC, ENT, and genes indicating the bacterial pathogens Shiga-toxin producing E. coli (STEC), Shigella spp., Salmonella spp, Campylobacter jejuni/coli, and methicillin-resistant Staphylococcus aureus, and 108–145 samples for Bacteroides human, ruminant, and gull source-marker genes. EC/ENT temporal patterns, general Bacteroides concentration, and pathogen types and occurrence were regionally consistent (up to 40 km), but beach catchment variables (drains/creeks, impervious surface, urban land cover) influenced exceedances of EC/ENT standards and detections of Salmonella and STEC. Pathogen detections were more numerous when the EC/ENT Beach Action Value (but not when the Geometric Mean and Statistical Threshold Value) was exceeded. EC, ENT, and pathogens were not necessarily influenced by the same variables. Multiple Bacteroides sources, varying by date, occurred at every beach. Study of multiple beaches in different geographic settings provided new insights on the contrasting influences of regional and local variables, and a broader-scale perspective, on significance of EC/ENT exceedances, bacterial sources, and pathogen occurrence.

Interaction of human, rat, and mouse immunoglobulin A (IgA) with Staphylococcal superantigen-like 7 (SSL7) decoy protein and leukocyte IgA receptor.

PubMed

Wines, Bruce D; Ramsland, Paul A; Trist, Halina M; Gardam, Sandra; Brink, Robert; Fraser, John D; Hogarth, P Mark

2011-09-23

Host survival depends on an effective immune system and pathogen survival on the effectiveness of immune evasion mechanisms. Staphylococcus aureus utilizes a number of molecules to modulate host immunity, including the SSL family of which SSL7 binds IgA and inhibits Fcα receptor I (FcαRI)-mediated function. Other Gram-positive bacterial pathogens produce IgA binding proteins, which, similar to SSL7, also bind the Fc at the CH2/CH3 interface (the junction between constant domains 2 and 3 of the heavy chain). The opposing activities of the host FcαRI-IgA receptor ligand pair and the pathogen decoy proteins select for host and pathogen variants, which exert stronger protection or evasion, respectively. Curiously, mouse but not rat IgA contains a putative N-linked glycosylation site in the center of this host receptor and pathogen-binding site. Here, we demonstrate that this site is glycosylated and that the effect of amino acid changes and glycosylation of the CH2/CH3 interface inhibits interaction with the pathogen IgA binding protein SSL7, while maintaining binding of pIgR, essential to the biosynthesis and transport of SIgA.

Strain Specific Phage Treatment for Staphylococcus aureus Infection Is Influenced by Host Immunity and Site of Infection.

PubMed

Pincus, Nathan B; Reckhow, Jensen D; Saleem, Danial; Jammeh, Momodou L; Datta, Sandip K; Myles, Ian A

2015-01-01

The response to multi-drug resistant bacterial infections must be a global priority. While mounting resistance threatens to create what the World Health Organization has termed a "post-antibiotic era", the recent discovery that antibiotic use may adversely impact the microbiome adds further urgency to the need for new developmental approaches for anti-pathogen treatments. Methicillin-resistant Staphylococcus aureus (MRSA), in particular, has declared itself a serious threat within the United States and abroad. A potential solution to the problem of antibiotic resistance may not entail looking to the future for completely novel treatments, but instead looking into our history of bacteriophage therapy. This study aimed to test the efficacy, safety, and commercial viability of the use of phages to treat Staphylococcus aureus infections using the commercially available phage SATA-8505. We found that SATA-8505 effectively controls S. aureus growth and reduces bacterial viability both in vitro and in a skin infection mouse model. However, this killing effect was not observed when phage was cultured in the presence of human whole blood. SATA-8505 did not induce inflammatory responses in peripheral blood mononuclear cultures. However, phage did induce IFN gamma production in primary human keratinocyte cultures and induced inflammatory responses in our mouse models, particularly in a mouse model of chronic granulomatous disease. Our findings support the potential efficacy of phage therapy, although regulatory and market factors may limit its wider investigation and use.

Draft Genome Sequences of 12 Clinical and Environmental Methicillin-Resistant Strains of Staphylococcus pseudintermedius Isolated from a Veterinary Teaching Hospital in Washington State

PubMed Central

Shah, Devendra H.; Jones, Lisa P.; Paul, Narayan

2018-01-01

ABSTRACT Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is a globally emergent multidrug-resistant pathogen of dogs associated with nosocomial transmission in dogs and with potential zoonotic impacts. Here, we report the draft whole-genome sequences of 12 hospital-associated MRSP strains and their resistance genotypes and phenotypes. PMID:29650582

Structural Insights into SraP-Mediated Staphylococcus aureus Adhesion to Host Cells

PubMed Central

Zhang, Juan; Wang, Lei; Bai, Xiao-Hui; Zhang, Shi-Jie; Ren, Yan-Min; Li, Na; Zhang, Yong-Hui; Zhang, Zhiyong; Gong, Qingguo; Mei, Yide; Xue, Ting; Zhang, Jing-Ren; Chen, Yuxing; Zhou, Cong-Zhao

2014-01-01

Staphylococcus aureus, a Gram-positive bacterium causes a number of devastating human diseases, such as infective endocarditis, osteomyelitis, septic arthritis and sepsis. S. aureus SraP, a surface-exposed serine-rich repeat glycoprotein (SRRP), is required for the pathogenesis of human infective endocarditis via its ligand-binding region (BR) adhering to human platelets. It remains unclear how SraP interacts with human host. Here we report the 2.05 Å crystal structure of the BR of SraP, revealing an extended rod-like architecture of four discrete modules. The N-terminal legume lectin-like module specifically binds to N-acetylneuraminic acid. The second module adopts a β-grasp fold similar to Ig-binding proteins, whereas the last two tandem repetitive modules resemble eukaryotic cadherins but differ in calcium coordination pattern. Under the conditions tested, small-angle X-ray scattering and molecular dynamic simulation indicated that the three C-terminal modules function as a relatively rigid stem to extend the N-terminal lectin module outwards. Structure-guided mutagenesis analyses, in addition to a recently identified trisaccharide ligand of SraP, enabled us to elucidate that SraP binding to sialylated receptors promotes S. aureus adhesion to and invasion into host epithelial cells. Our findings have thus provided novel structural and functional insights into the SraP-mediated host-pathogen interaction of S. aureus. PMID:24901708

Genetic Variation among Staphylococcus aureus Strains from Bovine Milk and Their Relevance to Methicillin-Resistant Isolates from Humans ▿

PubMed Central

Hata, Eiji; Katsuda, Ken; Kobayashi, Hideki; Uchida, Ikuo; Tanaka, Kiyoshi; Eguchi, Masashi

2010-01-01

In genetic analysis of bovine Staphylococcus aureus isolates that are recognized as an important pathogenic bacterium in bovine mastitis, multilocus sequence typing (MLST) showed strong correlation to the results of pulsed-field gel electrophoresis, coa PCR-restriction fragment length polymorphism (RFLP), spa typing, and the coagulase serotyping method. According to MLST results, strains derived from sequence type 97 (ST97) and ST705 were suggested as not only dominant bovine S. aureus lineages in Japan but also pandemic bovine S. aureus lineages. Although both lineages seem to be distantly related to each other by phylogenetic analysis, both had common characteristics, i.e., lukM/lukF′-PV and coagulase serotype VI. These characteristics were very rare among minor bovine strains and human strains and may contribute to the host specificity of these lineages. Four methicillin-resistant S. aureus (MRSA) isolates were first confirmed from bovine milk in Japan; these isolates showed geno- and serotypes that were identical or similar to those of human MRSA isolates in Japan (ST5, staphylococcal cassette chromosome mec type II [SCCmec II], Spa type t002 or t375, and coagulase serotype II, and ST89, SCCmec IIIa, Spa type t5266, and coagulase serotype I). ST5 and ST89 are uncommon among bovine isolates in the world, whereas these STs are common among human MRSA isolates in Japan. PMID:20392913

Duckweed (Lemna minor) as a model plant system for the study of human microbial pathogenesis.

PubMed

Zhang, Yong; Hu, Yangbo; Yang, Baoyu; Ma, Fang; Lu, Pei; Li, Lamei; Wan, Chengsong; Rayner, Simon; Chen, Shiyun

2010-10-25

Plant infection models provide certain advantages over animal models in the study of pathogenesis. However, current plant models face some limitations, e.g., plant and pathogen cannot co-culture in a contained environment. Development of such a plant model is needed to better illustrate host-pathogen interactions. We describe a novel model plant system for the study of human pathogenic bacterial infection on a large scale. This system was initiated by co-cultivation of axenic duckweed (Lemna minor) plants with pathogenic bacteria in 24-well polystyrene cell culture plate. Pathogenesis of bacteria to duckweed was demonstrated with Pseudomonas aeruginosa and Staphylococcus aureus as two model pathogens. P. aeruginosa PAO1 caused severe detriment to duckweed as judged from inhibition to frond multiplication and chlorophyll formation. Using a GFP-marked PAO1 strain, we demonstrated that bacteria colonized on both fronds and roots and formed biofilms. Virulence of PAO1 to duckweed was attenuated in its quorum sensing (QS) mutants and in recombinant strains overexpressing the QS quenching enzymes. RN4220, a virulent strain of S. aureus, caused severe toxicity to duckweed while an avirulent strain showed little effect. Using this system for antimicrobial chemical selection, green tea polyphenols exhibited inhibitory activity against S. aureus virulence. This system was further confirmed to be effective as a pathogenesis model using a number of pathogenic bacterial species. Our results demonstrate that duckweed can be used as a fast, inexpensive and reproducible model plant system for the study of host-pathogen interactions, could serve as an alternative choice for the study of some virulence factors, and could also potentially be used in large-scale screening for the discovery of antimicrobial chemicals.

Presence of Pathogens and Indicator Microbes at a Non-Point Source Subtropical Recreational Marine Beach ▿ †

PubMed Central

Abdelzaher, Amir M.; Wright, Mary E.; Ortega, Cristina; Solo-Gabriele, Helena M.; Miller, Gary; Elmir, Samir; Newman, Xihui; Shih, Peter; Bonilla, J. Alfredo; Bonilla, Tonya D.; Palmer, Carol J.; Scott, Troy; Lukasik, Jerzy; Harwood, Valerie J.; McQuaig, Shannon; Sinigalliano, Chris; Gidley, Maribeth; Plano, Lisa R. W.; Zhu, Xiaofang; Wang, John D.; Fleming, Lora E.

2010-01-01

Swimming in ocean water, including ocean water at beaches not impacted by known point sources of pollution, is an increasing health concern. This study was an initial evaluation of the presence of indicator microbes and pathogens and the association among the indicator microbes, pathogens, and environmental conditions at a subtropical, recreational marine beach in south Florida impacted by non-point sources of pollution. Twelve water and eight sand samples were collected during four sampling events at high or low tide under elevated or reduced solar insolation conditions. The analyses performed included analyses of fecal indicator bacteria (FIB) (fecal coliforms, Escherichia coli, enterococci, and Clostridium perfringens), human-associated microbial source tracking (MST) markers (human polyomaviruses [HPyVs] and Enterococcus faecium esp gene), and pathogens (Vibrio vulnificus, Staphylococcus aureus, enterovirus, norovirus, hepatitis A virus, Cryptosporidium spp., and Giardia spp.). The enterococcus concentrations in water and sand determined by quantitative PCR were greater than the concentrations determined by membrane filtration measurement. The FIB concentrations in water were below the recreational water quality standards for three of the four sampling events, when pathogens and MST markers were also generally undetectable. The FIB levels exceeded regulatory guidelines during one event, and this was accompanied by detection of HPyVs and pathogens, including detection of the autochthonous bacterium V. vulnificus in sand and water, detection of the allochthonous protozoans Giardia spp. in water, and detection of Cryptosporidium spp. in sand samples. The elevated microbial levels were detected at high tide and under low-solar-insolation conditions. Additional sampling should be conducted to further explore the relationships between tidal and solar insolation conditions and between indicator microbes and pathogens in subtropical recreational marine waters impacted by non-point source pollution. PMID:19966020

Duckweed (Lemna minor) as a Model Plant System for the Study of Human Microbial Pathogenesis

PubMed Central

Zhang, Yong; Hu, Yangbo; Yang, Baoyu; Ma, Fang; Lu, Pei; Li, Lamei; Wan, Chengsong; Rayner, Simon; Chen, Shiyun

2010-01-01

Background Plant infection models provide certain advantages over animal models in the study of pathogenesis. However, current plant models face some limitations, e.g., plant and pathogen cannot co-culture in a contained environment. Development of such a plant model is needed to better illustrate host-pathogen interactions. Methodology/Principal Findings We describe a novel model plant system for the study of human pathogenic bacterial infection on a large scale. This system was initiated by co-cultivation of axenic duckweed (Lemna minor) plants with pathogenic bacteria in 24-well polystyrene cell culture plate. Pathogenesis of bacteria to duckweed was demonstrated with Pseudomonas aeruginosa and Staphylococcus aureus as two model pathogens. P. aeruginosa PAO1 caused severe detriment to duckweed as judged from inhibition to frond multiplication and chlorophyll formation. Using a GFP-marked PAO1 strain, we demonstrated that bacteria colonized on both fronds and roots and formed biofilms. Virulence of PAO1 to duckweed was attenuated in its quorum sensing (QS) mutants and in recombinant strains overexpressing the QS quenching enzymes. RN4220, a virulent strain of S. aureus, caused severe toxicity to duckweed while an avirulent strain showed little effect. Using this system for antimicrobial chemical selection, green tea polyphenols exhibited inhibitory activity against S. aureus virulence. This system was further confirmed to be effective as a pathogenesis model using a number of pathogenic bacterial species. Conclusions/Significance Our results demonstrate that duckweed can be used as a fast, inexpensive and reproducible model plant system for the study of host-pathogen interactions, could serve as an alternative choice for the study of some virulence factors, and could also potentially be used in large-scale screening for the discovery of antimicrobial chemicals. PMID:21049039

Antibiotic-resistant bacteria: prevalence in food and inactivation by food-compatible compounds and plant extracts.

PubMed

Friedman, Mendel

2015-04-22

Foodborne antibiotic-resistant pathogenic bacteria such as Campylobacter jejuni, Bacillus cereus, Clostridium perfringens, Escherichia coli, Salmonella enterica, Staphylococcus aureus, Vibrio cholerae, and Vibrio parahemolyticus can adversely affect animal and human health, but a better understanding of the factors involved in their pathogenesis is needed. To help meet this need, this overview surveys and interprets much of our current knowledge of antibiotic (multidrug)-resistant bacteria in the food chain and the implications for microbial food safety and animal and human health. Topics covered include the origin and prevalence of resistant bacteria in the food chain (dairy, meat, poultry, seafood, and herbal products, produce, and eggs), their inactivation by different classes of compounds and plant extracts and by the use of chlorine and physicochemical methods (heat, UV light, pulsed electric fields, and high pressure), the synergistic antimicrobial effects of combinations of natural antimicrobials with medicinal antibiotics, and mechanisms of antimicrobial activities and resistant effects. Possible areas for future research are suggested. Plant-derived and other safe natural antimicrobial compounds have the potential to control the prevalence of both susceptible and resistant pathogens in various environments. The collated information and suggested research will hopefully contribute to a better understanding of approaches that could be used to minimize the presence of resistant pathogens in animal feed and human food, thus reducing adverse effects, improving microbial food safety, and helping to prevent or treat animal and human infections.

Characterization of a Staphylococcus aureus surface virulence factor that promotes resistance to oxidative killing and infectious endocarditis.

PubMed

Malachowa, Natalia; Kohler, Petra L; Schlievert, Patrick M; Chuang, Olivia N; Dunny, Gary M; Kobayashi, Scott D; Miedzobrodzki, Jacek; Bohach, Gregory A; Seo, Keun Seok

2011-01-01

Staphylococcus aureus is a prominent human pathogen and a leading cause of community- and hospital-acquired bacterial infections worldwide. Herein, we describe the identification and characterization of the S. aureus 67.6-kDa hypothetical protein, named for the surface factor promoting resistance to oxidative killing (SOK) in this study. Sequence analysis showed that the SOK gene is conserved in all sequenced S. aureus strains and homologous to the myosin cross-reactive antigen of Streptococcus pyogenes. Immunoblotting and immunofluorescence analysis showed that SOK was copurified with membrane fractions and was exposed on the surface of S. aureus Newman and RN4220. Comparative analysis of wild-type S. aureus and an isogenic deletion strain indicated that SOK contributes to both resistance to killing by human neutrophils and to oxidative stress. In addition, the S. aureus sok deletion strain showed dramatically reduced aortic valve vegetation and bacterial cell number in a rabbit endocarditis model. These results, plus the suspected role of the streptococcal homologue in certain diseases such as acute rheumatic fever, suggest that SOK plays an important role in cardiovascular and other staphylococcal infections.

Metabolic Mitigation of Staphylococcus aureus Vancomycin Intermediate-Level Susceptibility.

PubMed

Gardner, Stewart G; Marshall, Darrell D; Daum, Robert S; Powers, Robert; Somerville, Greg A

2018-01-01

Staphylococcus aureus is a major human pathogen whose infections are increasingly difficult to treat due to increased antibiotic resistance, including resistance to vancomycin. Vancomycin-intermediate S. aureus (VISA) strains develop resistance to vancomycin through adaptive changes that are incompletely understood. Central to this adaptation are metabolic changes that permit growth in the presence of vancomycin. To define the metabolic changes associated with adaptive resistance to vancomycin in S. aureus , the metabolomes of a vancomycin-sensitive and VISA strain pair isolated from the same patient shortly after vancomycin therapy began and following vancomycin treatment failure were analyzed. The metabolic adaptations included increases in acetogenesis, carbon flow through the pentose phosphate pathway, wall teichoic acid and peptidoglycan precursor biosynthesis, purine biosynthesis, and decreased tricarboxylic acid (TCA) cycle activity. The significance of these metabolic pathways for vancomycin-intermediate susceptibility was determined by assessing the synergistic potential of human-use-approved inhibitors of these pathways in combination with vancomycin against VISA strains. Importantly, inhibitors of amino sugar and purine biosynthesis acted synergistically with vancomycin to kill a diverse set of VISA strains, suggesting that combinatorial therapy could augment the efficacy of vancomycin even in patients infected with VISA strains. Copyright © 2017 American Society for Microbiology.

Study on antibacterial effect of medlar and hawthorn compound extract in vitro.

PubMed

Niu, Yang; Nan, Yi; Yuan, Ling; Wang, Rong

2013-01-01

This paper evaluated the antibacterial effect of medlar and hawthorn compound extract in vitro. Water extract method and ethanol extraction method was adopted to prepare the compound extracts, and disc diffusion method and improved test tube doubling dilution method were used to conduct the antibacterial test on the two common pathogenic bacteria, Staphylococcus aureus and Klebsiella pneumonia, in vitro. The results showed that medlar and hawthorn compound extract was moderately sensitive to Staphylococcus aureus, while its inhibiting effect on Klebsiella pneumoniae was particularly significant, moreover, the antibacterial effect of ethanol extract was better than water extract. Medlar and hawthorn compounds had good antibacterial effect on the two pathogenic bacteria.

Topical Antimicrobial Treatments Can Elicit Shifts to Resident Skin Bacterial Communities and Reduce Colonization by Staphylococcus aureus Competitors.

PubMed

SanMiguel, Adam J; Meisel, Jacquelyn S; Horwinski, Joseph; Zheng, Qi; Grice, Elizabeth A

2017-09-01

The skin microbiome is a complex ecosystem with important implications for cutaneous health and disease. Topical antibiotics and antiseptics are often employed to preserve the balance of this population and inhibit colonization by more pathogenic bacteria. However, despite their widespread use, the impact of these interventions on broader microbial communities remains poorly understood. Here, we report the longitudinal effects of topical antibiotics and antiseptics on skin bacterial communities and their role in Staphylococcus aureus colonization resistance. In response to antibiotics, cutaneous populations exhibited an immediate shift in bacterial residents, an effect that persisted for multiple days posttreatment. By contrast, antiseptics elicited only minor changes to skin bacterial populations, with few changes to the underlying microbiota. While variable in scope, both antibiotics and antiseptics were found to decrease colonization by commensal Staphylococcus spp. by sequencing- and culture-based methods, an effect which was highly dependent on baseline levels of Staphylococcus Because Staphylococcus residents have been shown to compete with the skin pathogen S. aureus , we also tested whether treatment could influence S. aureus levels at the skin surface. We found that treated mice were more susceptible to exogenous association with S. aureus and that precolonization with the same Staphylococcus residents that were previously disrupted by treatment reduced S. aureus levels by over 100-fold. In all, the results of this study indicate that antimicrobial drugs can alter skin bacterial residents and that these alterations can have critical implications for cutaneous host defense. Copyright © 2017 American Society for Microbiology.

A pilot study of an anti-MRSA bio-engineered lacteal complex (anti-MRSA BLC) in a murine septicemia model.

PubMed

Stoff, Jesse A; Nix, David E; DeYoung, D W

2006-01-01

Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen of humans and other animals, causing septicemia, abcessation, toxemia, and other infectious diseases. Refined bioengineered lacteal complex (BLC), made specifically against MRSA, is a novel complex of low molecular weight immunogenic and antimicrobial molecules. It was evaluated in vivo using a mouse model of MRSA-induced peritonitis. Intraperitoneal dosing of anti-MRSA BLC demonstrated a therapeutic effect (83% survival) against an intraperitoneal MRSA challenge that caused 100% mortality in untreated animals. Anti-MRSA BLC is a promising therapeutic modality for MRSA infection.

Transfer of mupirocin resistance from Staphylococcus haemolyticus clinical strains to Staphylococcus aureus through conjugative and mobilizable plasmids.

PubMed

Rossi, Ciro C; Ferreira, Natália C; Coelho, Marcus L V; Schuenck, Ricardo P; Bastos, Maria do Carmo de F; Giambiagi-deMarval, Marcia

2016-07-01

Coagulase-negative staphylococci are thought to act as reservoirs of antibiotic resistance genes that can be transferred to Staphylococcus aureus, thus hindering the combat of this bacterium. In this work, we analyzed the presence of plasmids conferring resistance to the antibiotic mupirocin-widely used to treat and prevent S. aureus infections in hospital environments-in nosocomial S. haemolyticus strains. About 12% of the 75 strains tested were resistant to mupirocin, and this phenotype was correlated with the presence of plasmids. These plasmids were shown to be diverse, being either conjugative or mobilizable, and capable of transferring mupirocin resistance to S. aureus Our findings reinforce that S. haemolyticus, historically and mistakenly considered as a less important pathogen, is a reservoir of resistance genes which can be transferred to other bacteria, such as S. aureus, emphasizing the necessity of more effective strategies to detect and combat this emergent opportunistic pathogen. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Prevalence of contagious mastitis pathogens in bulk tank milk in Québec

PubMed Central

Francoz, David; Bergeron, Luc; Nadeau, Marie; Beauchamp, Guy

2012-01-01

The objective of this study was to estimate the prevalence of mycoplasma, Staphylococcus aureus, and Streptococcus agalactiae in bulk tank milk (BTM) in Québec dairy herds. BTM was sampled 3 times a month in 117 randomly selected dairy herds. Samples were submitted for S. aureus, S. agalactiae, and mycoplasma and for direct mycoplasma detection by polymerase chain reaction (PCR). Mycoplasma spp. was identified at least once in 3 herds (2.6%) by primary culture and/or PCR and in 4 herds (3.4%) by enrichment culture and/or PCR. Staphylococcus aureus was isolated at least once in 99 (84.6%) and 112 (95.7%) herds in primary culture and after enrichment, respectively. Streptococcus agalactiae was isolated at least once in 9 (7.7%) and 10 (8.6%) herds in primary culture and after enrichment, respectively. Herd prevalence of mycoplasma was similar to that previously reported in Canada. Staphylococcus aureus is still by far the most important contagious mastitis pathogen. PMID:23543925

East and West African milk products are reservoirs for human and livestock-associated Staphylococcus aureus.

PubMed

Jans, Christoph; Merz, Axel; Johler, Sophia; Younan, Mario; Tanner, Sabine A; Kaindi, Dasel Wambua Mulwa; Wangoh, John; Bonfoh, Bassirou; Meile, Leo; Tasara, Taurai

2017-08-01

Staphylococcus aureus frequently isolated from milk products in sub-Saharan Africa (SSA) is a major pathogen responsible for food intoxication, human and animal diseases. SSA hospital-derived strains are well studied but data on the population structure of foodborne S. aureus required to identify possible staphylococcal food poisoning sources is lacking. Therefore, the aim was to assess the population genetic structure, virulence and antibiotic resistance genes associated with milk-derived S. aureus isolates from Côte d'Ivoire, Kenya and Somalia through spa-typing, MLST, and DNA microarray analysis. Seventy milk S. aureus isolates from the three countries were assigned to 27 spa (7 new) and 23 (12 new) MLST sequence types. Milk-associated S. aureus of the three countries is genetically diverse comprising human and livestock-associated clonal complexes (CCs) predominated by the CC5 (n = 10) and CC30 (n = 9) isolates. Panton-Valentine leukocidin, toxic shock syndrome toxin and enterotoxin encoding genes were predominantly observed among human-associated CCs. Penicillin, fosfomycin and tetracycline, but not methicillin resistance genes were frequently detected. Our findings indicate that milk-associated S. aureus in SSA originates from human and animal sources alike highlighting the need for an overarching One Health approach to reduce S. aureus disease burdens through improving production processes, animal care and hygienic measures. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Analysis of the pathogenic characteristics of 162 severely burned patients with bloodstream infection].

PubMed

Gong, Y L; Yang, Z C; Yin, S P; Liu, M X; Zhang, C; Luo, X Q; Peng, Y Z

2016-09-20

To analyze the distribution and drug resistance of pathogen isolated from severely burned patients with bloodstream infection, so as to provide reference for the clinical treatment of these patients. Blood samples of 162 severely burned patients (including 120 patients with extremely severe burn) with bloodstream infection admitted into our burn ICU from January 2011 to December 2014 were collected. Pathogens were cultured by fully automatic blood culture system, and API bacteria identification panels were used to identify pathogen. Kirby-Bauer paper disk diffusion method was used to detect the drug resistance of major Gram-negative and -positive bacteria to 37 antibiotics including ampicillin, piperacillin and teicoplanin, etc. (resistance to vancomycin was detected by E test), and drug resistance of fungi to 5 antibiotics including voriconazole and amphotericin B, etc. Modified Hodge test was used to further identify imipenem and meropenem resistant Klebsiella pneumonia. D test was used to detect erythromycin-induced clindamycin resistant Staphylococcus aureus. The pathogen distribution and drug resistance rate were analyzed by WHONET 5.5. Mortality rate and infected pathogens of patients with extremely severe burn and patients with non-extremely severe burn were recorded. Data were processed with Wilcoxon rank sum test. (1) Totally 1 658 blood samples were collected during the four years, and 339 (20.4%) strains of pathogens were isolated. The isolation rate of Gram-negative bacteria, Gram-positive bacteria, and fungi were 68.4% (232/339), 24.5% (83/339), and 7.1% (24/339), respectively. The top three pathogens with isolation rate from high to low were Acinetobacter baumannii, Staphylococcus aureus, and Pseudomonas aeruginosa in turn. (2) Except for the low drug resistance rate to polymyxin B and minocycline, drug resistance rate of Acinetobacter baumannii to the other antibiotics were relatively high (81.0%-100.0%). Pseudomonas aeruginosa was sensitive to polymyxin B but highly resistant to other antibiotics (57.7%-100.0%). Enterobacter cloacae was sensitive to imipenem and meropenem, while its drug resistance rates to ciprofloxacin, levofloxacin, cefoperazone/sulbactam, cefepime, piperacillin/tazobactam were 25.0%-49.0%, and those to the other antibiotics were 66.7%-100.0%. Drug resistance rates of Klebsiella pneumoniae to cefoperazone/sulbactam, imipenem, and meropenem were low (5.9%-15.6%, two imipenem- and meropenem-resistant strains were identified by modified Hodge test), while its drug resistance rates to amoxicillin/clavulanic acid, piperacillin/tazobactam, cefepime, cefoxitin, amikacin, levofloxacin were 35.3%-47.1%, and those to the other antibiotics were 50.0%-100.0%. (3) Drug resistance rates of methicillin-resistant Staphylococcus aureus (MRSA) to most of the antibiotics were higher than those of the methicillin-sensitive Staphylococcus aureus (MSSA). MRSA was sensitive to linezolid, vancomycin, and teicoplanin, while its drug resistance rates to compound sulfamethoxazole, clindamycin, minocycline, and erythromycin were 5.3%-31.6%, and those to the other antibiotics were 81.6%-100.0%. Except for totally resistant to penicillin G and tetracycline, MSSA was sensitive to the other antibiotics. Fourteen Staphylococcus aureus strains were resistant to erythromycin-induced clindamycin. Enterococcus was sensitive to vancomycin and teicoplanin, while its drug resistance rates to linezolid, chloramphenicol, nitrofurantoin, and high unit gentamicin were low (10.0%-30.0%), and those to ciprofloxacin, erythromycin, minocycline, and ampicillin were high (60.0%-80.0%). Enterococcus was fully resistant to rifampicin. (4) Fungi was sensitive to amphotericin B, and drug resistance rates of fungi to voriconazole, fluconazole, itraconazole, and ketoconazole were 7.2%-12.5%. (5) The mortality of patients with extremely severe burn was higher than that of patients with non-extremely severe burn. The variety of infected pathogens in patients with extremely severe burn significantly outnumbered that in patients with non-extremely severe burn (Z=-2.985, P=0.005). The variety of pathogen in severely burned patients with bloodstream infection is wide, with the main pathogens as Acinetobacter baumannii, Staphylococcus aureus, and Pseudomonas aeruginosa, and the drug resistance situation is grim. The types of infected pathogen in patients with extremely severe burn are more complex, and the mortality of these patients is higher when compared with that of patients with non-extremely severe burn.

Clinical Characteristics and In-Hospital Prognosis of Infective Endocarditis in Two Eastern Counties of Taiwan

PubMed Central

Hsieh, Jen-Che; Wang, Ling-Yi; Chang, Huai-Ren; Chao, Shen-Feng; Wang, Ji-Hung

2014-01-01

Background Infective endocarditis (IE) is a common and potentially serious disease. Although it is an illness that affects populations around the world, narrower descriptions of this disease as it impacts specific regions are uncommon. We analyzed the clinical characteristics of IE patients from two eastern counties in Taiwan and studied the relationship between the isolated pathogens and clinical outcomes in these patients. Methods This is a retrospective chart review study which enrolled patients who received services between January 2007 and December 2010. Subsequent to chart review, IE was confirmed in a total of 55 patients by the modified Duke criteria. Results Of these patients, 17 (31%) had previous traumatic open skin wounds. Pre-existing cardiac abnormalities were found in 47 (85%) patients, 28 of whom had valvular abnormalities. Staphylococcus aureus was isolated from the blood as the leading pathogen in 25 (45%) patients (including 23 methicillin-sensitive and 2 methicillin-resistant). Septic emboli and shock occurred in 27 (49%) of 55 patients; surgery was performed on 11 (20%) of those patients, and 4 (36%) of them died post-operatively. The total in-hospital mortality rate was 40% (n = 22). Staphylococcus aureus infection was associated with significantly higher complication and mortality rate than non-Staphylococcus aureus infection (59% vs. 41% and 64% vs. 36%, respectively; p < 0.05). In addition, patients with complications had a very high mortality rate (81.5%). Conclusions We found that Staphylococcus aureus was the most common pathogen of IE in Eastern Taiwan, and was associated with higher rates of morbidities and mortality. PMID:27122782

Staphylococcus haemolyticus as an important hospital pathogen and carrier of methicillin resistance genes.

PubMed

Barros, E M; Ceotto, H; Bastos, M C F; Dos Santos, K R N; Giambiagi-Demarval, M

2012-01-01

Phenotypic and molecular methods were used to characterize the antibiotic resistance of 64 clinical isolates of Staphylococcus haemolyticus. By PCR of the mecA gene, 87% were found to be methicillin resistant. Approximately 55% harbored staphylococcal cassette chromosome mec element (SCCmec) type V, and only one SCCmec type IV. Many isolates (75%) displayed multiresistance, and pulsotype analysis showed a high diversity.

Draft Genome Sequences of 12 Clinical and Environmental Methicillin-Resistant Staphylococcus pseudintermedius Strains Isolated from a Veterinary Teaching Hospital in Washington State.

PubMed

Shah, Devendra H; Jones, Lisa P; Paul, Narayan; Davis, Margaret A

2018-04-12

Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is a globally emergent multidrug-resistant pathogen of dogs associated with nosocomial transmission in dogs and with potential zoonotic impacts. Here, we report the draft whole-genome sequences of 12 hospital-associated MRSP strains and their resistance genotypes and phenotypes. Copyright © 2018 Shah et al.

Selected Pathogens of Concern to Industrial Food Processors: Infectious, Toxigenic, Toxico-Infectious, Selected Emerging Pathogenic Bacteria

NASA Astrophysics Data System (ADS)

Behling, Robert G.; Eifert, Joseph; Erickson, Marilyn C.; Gurtler, Joshua B.; Kornacki, Jeffrey L.; Line, Erick; Radcliff, Roy; Ryser, Elliot T.; Stawick, Bradley; Yan, Zhinong

This chapter, written by several contributing authors, is devoted to discussing selected microbes of contemporary importance. Microbes from three categories are described by the following: (1) infectious invasive agents like Salmonella, Listeria monocytogenes, and Campylobacter; (2) toxigenic pathogens such as Staphylococcus aureus, Bacillus cereus, and Clostridium botulinum; and (3) toxico-infectious agents like enterohemorrhagic Escherichia coli and Clostridium perfringens. In addition, emerging pathogens, like Cronobacter (Enterobacter) sakazakii, Arcobacter spp., and Mycobacterium avium subspecies paratuberculosis are also described.

From clinical microbiology to infection pathogenesis: how daring to be different works for Staphylococcus lugdunensis.

PubMed

Frank, Kristi L; Del Pozo, José Luis; Patel, Robin

2008-01-01

Staphylococcus lugdunensis has gained recognition as an atypically virulent pathogen with a unique microbiological and clinical profile. S. lugdunensis is coagulase negative due to the lack of production of secreted coagulase, but a membrane-bound form of the enzyme present in some isolates can result in misidentification of the organism as Staphylococcus aureus in the clinical microbiology laboratory. S. lugdunensis is a skin commensal and an infrequent pathogen compared to S. aureus and S. epidermidis, but clinically, infections caused by this organism resemble those caused by S. aureus rather than those caused by other coagulase-negative staphylococci. S. lugdunensis can cause acute and highly destructive cases of native valve endocarditis that often require surgical treatment in addition to antimicrobial therapy. Other types of S. lugdunensis infections include abscess and wound infection, urinary tract infection, and infection of intravascular catheters and other implanted medical devices. S. lugdunensis is generally susceptible to antimicrobial agents and shares CLSI antimicrobial susceptibility breakpoints with S. aureus. Virulence factors contributing to this organism's heightened pathogenicity remain largely unknown. Those characterized to date suggest that the organism has the ability to bind to and interact with host cells and to form biofilms on host tissues or prosthetic surfaces.

From Clinical Microbiology to Infection Pathogenesis: How Daring To Be Different Works for Staphylococcus lugdunensis

PubMed Central

Frank, Kristi L.; del Pozo, José Luis; Patel, Robin

2008-01-01

Staphylococcus lugdunensis has gained recognition as an atypically virulent pathogen with a unique microbiological and clinical profile. S. lugdunensis is coagulase negative due to the lack of production of secreted coagulase, but a membrane-bound form of the enzyme present in some isolates can result in misidentification of the organism as Staphylococcus aureus in the clinical microbiology laboratory. S. lugdunensis is a skin commensal and an infrequent pathogen compared to S. aureus and S. epidermidis, but clinically, infections caused by this organism resemble those caused by S. aureus rather than those caused by other coagulase-negative staphylococci. S. lugdunensis can cause acute and highly destructive cases of native valve endocarditis that often require surgical treatment in addition to antimicrobial therapy. Other types of S. lugdunensis infections include abscess and wound infection, urinary tract infection, and infection of intravascular catheters and other implanted medical devices. S. lugdunensis is generally susceptible to antimicrobial agents and shares CLSI antimicrobial susceptibility breakpoints with S. aureus. Virulence factors contributing to this organism's heightened pathogenicity remain largely unknown. Those characterized to date suggest that the organism has the ability to bind to and interact with host cells and to form biofilms on host tissues or prosthetic surfaces. PMID:18202439

Rapid single cell detection of Staphylococcus aureus by aptamer-conjugated gold nanoparticles

PubMed Central

Chang, Yi-Chung; Yang, Chia-Ying; Sun, Ruei-Lin; Cheng, Yi-Feng; Kao, Wei-Chen; Yang, Pan-Chyr

2013-01-01

Staphylococcus aureus is one of the most important human pathogens, causing more than 500,000 infections in the United States each year. Traditional methods for bacterial culture and identification take several days, wasting precious time for patients who are suffering severe bacterial infections. Numerous nucleic acid-based detection methods have been introduced to address this deficiency; however, the costs and requirement for expensive equipment may limit the widespread use of such technologies. Thus, there is an unmet demand of new platform technology to improve the bacterial detection and identification in clinical practice. In this study, we developed a rapid, ultra-sensitive, low cost, and non-polymerase chain reaction (PCR)-based method for bacterial identification. Using this method, which measures the resonance light-scattering signal of aptamer-conjugated gold nanoparticles, we successfully detected single S. aureus cell within 1.5 hours. This new platform technology may have potential to develop a rapid and sensitive bacterial testing at point-of-care. PMID:23689505

Rapid single cell detection of Staphylococcus aureus by aptamer-conjugated gold nanoparticles.

PubMed

Chang, Yi-Chung; Yang, Chia-Ying; Sun, Ruei-Lin; Cheng, Yi-Feng; Kao, Wei-Chen; Yang, Pan-Chyr

2013-01-01

Staphylococcus aureus is one of the most important human pathogens, causing more than 500,000 infections in the United States each year. Traditional methods for bacterial culture and identification take several days, wasting precious time for patients who are suffering severe bacterial infections. Numerous nucleic acid-based detection methods have been introduced to address this deficiency; however, the costs and requirement for expensive equipment may limit the widespread use of such technologies. Thus, there is an unmet demand of new platform technology to improve the bacterial detection and identification in clinical practice. In this study, we developed a rapid, ultra-sensitive, low cost, and non-polymerase chain reaction (PCR)-based method for bacterial identification. Using this method, which measures the resonance light-scattering signal of aptamer-conjugated gold nanoparticles, we successfully detected single S. aureus cell within 1.5 hours. This new platform technology may have potential to develop a rapid and sensitive bacterial testing at point-of-care.

Life and death of proteins: a case study of glucose-starved Staphylococcus aureus.

PubMed

Michalik, Stephan; Bernhardt, Jörg; Otto, Andreas; Moche, Martin; Becher, Dörte; Meyer, Hanna; Lalk, Michael; Schurmann, Claudia; Schlüter, Rabea; Kock, Holger; Gerth, Ulf; Hecker, Michael

2012-09-01

The cellular amount of proteins not only depends on synthesis but also on degradation. Here, we expand the understanding of differential protein levels by complementing synthesis data with a proteome-wide, mass spectrometry-based stable isotope labeling with amino acids in cell culture analysis of protein degradation in the human pathogen Staphylococcus aureus during glucose starvation. Monitoring protein stability profiles in a wild type and an isogenic clpP protease mutant revealed that 1) proteolysis mainly affected proteins with vegetative functions, anabolic and selected catabolic enzymes, whereas the expression of TCA cycle and gluconeogenesis enzymes increased; 2) most proteins were prone to aggregation in the clpP mutant; 3) the absence of ClpP correlated with protein denaturation and oxidative stress responses, deregulation of virulence factors and a CodY repression. We suggest that degradation of redundant, inactive proteins disintegrated from functional complexes and thereby amenable to proteolytic attack is a fundamental cellular process in all organisms to regain nutrients and guarantee protein homeostasis.

Life and Death of Proteins: A Case Study of Glucose-starved Staphylococcus aureus*

PubMed Central

Michalik, Stephan; Bernhardt, Jörg; Otto, Andreas; Moche, Martin; Becher, Dörte; Meyer, Hanna; Lalk, Michael; Schurmann, Claudia; Schlüter, Rabea; Kock, Holger; Gerth, Ulf; Hecker, Michael

2012-01-01

The cellular amount of proteins not only depends on synthesis but also on degradation. Here, we expand the understanding of differential protein levels by complementing synthesis data with a proteome-wide, mass spectrometry-based stable isotope labeling with amino acids in cell culture analysis of protein degradation in the human pathogen Staphylococcus aureus during glucose starvation. Monitoring protein stability profiles in a wild type and an isogenic clpP protease mutant revealed that 1) proteolysis mainly affected proteins with vegetative functions, anabolic and selected catabolic enzymes, whereas the expression of TCA cycle and gluconeogenesis enzymes increased; 2) most proteins were prone to aggregation in the clpP mutant; 3) the absence of ClpP correlated with protein denaturation and oxidative stress responses, deregulation of virulence factors and a CodY repression. We suggest that degradation of redundant, inactive proteins disintegrated from functional complexes and thereby amenable to proteolytic attack is a fundamental cellular process in all organisms to regain nutrients and guarantee protein homeostasis. PMID:22556279

Crystal structure and substrate specificity of the [beta]-ketoacyl-acyl carrier protein synthase III (FabH) from Staphylococcus aureus

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

Qiu, Xiayang; Choudhry, Anthony E.; Janson, Cheryl A.

{beta}-Ketoacyl-ACP synthase III (FabH), an essential enzyme for bacterial viability, catalyzes the initiation of fatty acid elongation by condensing malonyl-ACP with acetyl-CoA. We have determined the crystal structure of FabH from Staphylococcus aureus, a Gram-positive human pathogen, to 2 {angstrom} resolution. Although the overall structure of S. aureus FabH is similar to that of Escherichia coli FabH, the primer binding pocket in S. aureus FabH is significantly larger than that present in E. coli FabH. The structural differences, which agree with kinetic parameters, provide explanation for the observed varying substrate specificity for E. coli and S. aureus FabH. The rankmore » order of activity of S. aureus FabH with various acyl-CoA primers was as follows: isobutyryl- > hexanoyl- > butyryl- > isovaleryl- >> acetyl-CoA. The availability of crystal structure may aid in designing potent, selective inhibitors of S. aureus FabH.« less

The effect of temperature and Pasteurization time on Staphylococcus aureus isolates from dairy products

NASA Astrophysics Data System (ADS)

Yaniarti, Maria Nia; Amarantini, Charis; Budiarso, Tri Yahya

2017-11-01

Staphylococcus aureus is a potential pathogenic bacterial cause of disease in humans and animals due to the ability of adhesion to epithelial tissue. Many cases of food poisoning are caused by S. aureus bacteria. Therefore, the purpose of this study was to determine the effect of temperature and time on the growth of S. aureus isolates from milk products. The samples are derived from previous research namely pasteurized milk, street vendor and café milk, milk powder, and sweetened condensed milk products. The treatment temperatures and times studied were temperature 60 °C, 65 °C, 70 °C, 75 °C, 80 °C, and 30, 35, 40, 45, 50, 55, and 60 minutes. The results show that at temperatures of 60 °C and 65 °C, S. aureus isolates did not grow at 60 minutes. All isolates of S. aureus died when the temperatures were increased to 70 °C and 80 °C, at 50 and 20 minutes, respectively.

Triclosan Promotes Staphylococcus aureus Nasal Colonization

PubMed Central

Syed, Adnan K.; Ghosh, Sudeshna; Love, Nancy G.; Boles, Blaise R.

2014-01-01

ABSTRACT The biocide triclosan is used in many personal care products, including toothpastes, soaps, clothing, and medical equipment. Consequently, it is present as a contaminant in the environment and has been detected in some human fluids, including serum, urine, and milk. Staphylococcus aureus is an opportunistic pathogen that colonizes the noses and throats of approximately 30% of the population. Colonization with S. aureus is known to be a risk factor for several types of infection. Here we demonstrate that triclosan is commonly found in the nasal secretions of healthy adults and the presence of triclosan trends positively with nasal colonization by S. aureus. We demonstrate that triclosan can promote the binding of S. aureus to host proteins such as collagen, fibronectin, and keratin, as well as inanimate surfaces such as plastic and glass. Lastly, triclosan-exposed rats are more susceptible to nasal colonization with S. aureus. These data reveal a novel factor that influences the ability of S. aureus to bind surfaces and alters S. aureus nasal colonization. PMID:24713325

Staphylococcus aureus secretes a unique class of neutrophil serine protease inhibitors

PubMed Central

Stapels, Daphne A. C.; Ramyar, Kasra X.; Bischoff, Markus; von Köckritz-Blickwede, Maren; Milder, Fin J.; Ruyken, Maartje; Eisenbeis, Janina; McWhorter, William J.; Herrmann, Mathias; van Kessel, Kok P. M.; Geisbrecht, Brian V.; Rooijakkers, Suzan H. M.

2014-01-01

Neutrophils are indispensable for clearing infections with the prominent human pathogen Staphylococcus aureus. Here, we report that S. aureus secretes a family of proteins that potently inhibits the activity of neutrophil serine proteases (NSPs): neutrophil elastase (NE), proteinase 3, and cathepsin G. The NSPs, but not related serine proteases, are specifically blocked by the extracellular adherence protein (Eap) and the functionally orphan Eap homologs EapH1 and EapH2, with inhibitory-constant values in the low-nanomolar range. Eap proteins are together essential for NSP inhibition by S. aureus in vitro and promote staphylococcal infection in vivo. The crystal structure of the EapH1/NE complex showed that Eap molecules constitute a unique class of noncovalent protease inhibitors that occlude the catalytic cleft of NSPs. These findings increase our insights into the complex pathogenesis of S. aureus infections and create opportunities to design novel treatment strategies for inflammatory conditions related to excessive NSP activity. PMID:25161283

The inhibition of methicillin-resistant Staphylococcus aureus by essential oils isolated from leaves and fruits of Schinus areira depending on their chemical compositions.

PubMed

Celaya, Liliana S; Alabrudzińska, Marta H; Molina, Ana C; Viturro, Carmen I; Moreno, Silvia

2014-01-01

Schinus areira L. is a native plant from South America used for centuries in traditional medicine. Here, we investigate the antimicrobial activity of four essential oils extracted from leaves and fruits of S. areira exhibiting different chemical profiles. The antibacterial activity against the human pathogenic bacteria Staphylococcus aureus susceptible as well as methicillin resistant strain was assessed by the broth microdilution assay. The results showed that the limonene-rich oil extracted from the leaves and fruits have potent antibacterial effect on S. aureus ATCC 25923, while the α-phellandrene-rich fruit oil having a lower content of limonene showed the lowest antibacterial efficacy. In this work, for the first time, we demonstrated the bactericidal activity of essential oils isolated from fruits and leaves of S. areira against susceptible and methicillin resistant S. aureus strains. All results point out the potential use of the S. areira oils as antimicrobial agents to be used, at least against Staphylococcal infections.

A retrospective analysis of antimicrobial resistance in bacterial pathogens in an equine hospital (2012-2015).

PubMed

van Spijk, J N; Schmitt, S; Fürst, A E; Schoster, A

2016-06-01

Antimicrobial resistance has become an important concern in veterinary medicine. The aim of this study was to describe the rate of antimicrobial resistance in common equine pathogens and to determine the occurrence of multidrug-resistant isolates. A retrospective analysis of all susceptibility testing results from bacterial pathogens cultured from horses at the University of Zurich Equine Hospital (2012-2015) was performed. Strains exhibiting resistance to 3 or more antimicrobial categories were defined as multidrug-resistant. Susceptibility results from 303 bacterial pathogens were analyzed, most commonly Escherichia coli (60/303, 20%) and Staphylococcus aureus (40/303, 13%). High rates of acquired resistance against commonly used antimicrobials were found in most of the frequently isolated equine pathogens. The highest rate of multidrug resistance was found in isolates of Acinetobacter baumannii (23/24, 96%), followed by Enterobacter cloacae complex (24/28, 86%) and Escherichia coli (48/60, 80%). Overall, 60% of Escherichia coli isolates were phenotypically ESBL-producing and 68% of Staphylococcus spp. were phenotypically methicillin-resistant. High rates of acquired antimicrobial resistance towards commonly used antibiotics are concerning and underline the importance of individual bacteriological and antimicrobial susceptibility testing to guide antimicrobial therapy. Minimizing and optimizing antimicrobial therapy in horses is needed.

Short communication: Outbreak of methicillin-resistant Staphylococcus aureus (MRSA)-associated mastitis in a closed dairy herd.

PubMed

Guimarães, F F; Manzi, M P; Joaquim, S F; Richini-Pereira, V B; Langoni, H

2017-01-01

Cows are probably the main source of contamination of raw milk with Staphylococcus aureus. Mammary glands with subclinical mastitis can shed large numbers of Staph. aureus in milk. Because of the risk of this pathogen to human health as well as animal health, the aim of this paper was to describe an outbreak of mastitis caused by methicillin-resistant Staph. aureus (MRSA), oxacillin-susceptible mecA-positive Staph. aureus (OS-MRSA), and methicillin-susceptible Staph. aureus (MSSA) on a dairy farm. Milk samples were obtained from all quarters, showing an elevated somatic cell count by the California Mastitis Test. The isolates were identified by phenotypic and genotypic methods. Staphylococcus spp. were isolated from 53% (61/115) of the milk samples, with 60 isolates identified as Staph. aureus (98.4%) and 1 isolate identified as Staphylococcus epidermidis (1.6%). The presence of the mecA gene was verified in 48.3% of Staph. aureus isolates. Of the Staph. aureus isolates, 23.3% were MRSA and 25.0% were OS-MRSA. The total of mastitis cases infected with MRSA was 12.2%. The detection of this large percentage of mastitis cases caused by MRSA and OS-MRSA is of great concern for the animals' health, because β-lactams are still the most important antimicrobials used to treat mastitis. In addition, Staph. aureus isolates causing bovine mastitis represent a public health risk. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

[Epidemiology of Staphylococcus aureus nosocomial infections in a high-risk neonatal unit].

PubMed

Velazco, Elsa; Nieves, Beatriz; Araque, María; Calderas, Zoila

2002-01-01

Nosocomial infections are a significant cause of morbidity and mortality throughout the world. In developing countries it is difficult to carry out effective surveillance and control programs for this type of infection because of the cost in both human and material resources. These considerations prompted us to perform a prospective study to determine the epidemiologic and microbiologic characteristics of nosocomial infections due to Staphylococcus aureus in the High-risk Neonatal Unit (HRNU) of the Instituto Autónomo Hospital Universitario de Los Andes (IAHULA), during the period of November 1997 to October 1998. Among a total of 120 microorganisms, 24 (20%) strains of Staphylococcus aureus were isolated; 47% were recovered from blood and 33% from conjunctive samples. Among the cases of conjunctivitis, S. aureus was the only pathogen isolated in 42%. Twenty of the 24 Staphylococcus aureus strains (83%) were methicillin-resistant (MRSA). According to their resistance profiles, we established 12 groups of strains from neonates with nosocomial infections and 1 group of strains from the two carriers among the healthcare personnel detected by microbiological screening. The MeRGmR pattern was the most frequent. Plasmid analysis disclosed two profiles, each having a plasmid molecular weight over 23.130 bp. The MRSA strains isolated from the neonates and those isolated from the carriers showed the same plasmid profile. This suggests that the healthcare personnel may have acted as reservoirs of the MRSA strains found in neonates with nosocomial infection.

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. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Comparison of antibiotic resistance, virulence gene profiles, and pathogenicity of methicillin-resistant and methicillin-susceptible Staphylococcus aureus using a Caenorhabditis elegans infection model

PubMed Central

Thompson, Terissa; Brown, Paul D

2014-01-01

Objectives: This study compared the presence of 35 virulence genes, resistance phenotypes to 11 anti-staphylococcal antibiotics, and pathogenicity in methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S. aureus (MSSA). Methods: Multiplex PCR analysis was used to differentiate Staphylococcus aureus isolates (n = 102) based on characterization of the Staphylococcal Cassette Chromosome mec (SCCmec). Singleplex and multiplex PCR assays targeting 35 virulence determinants were used to analyze the virulence repertoire of S. aureus. In vitro activities of the antibiotics were determined by the disk-diffusion method. The pathogenicity of representative isolates was assessed using Caenorhabditis elegans survival assays. Significance in virulence distribution and antibiotic resistance phenotypes was assessed using the Chi-squared tests. Kaplan–Meier survival estimates were used to analyze nematode survival and significance of survival rates evaluated using the log-rank test. Results: Except for sei (staphylococcal enterotoxin I) (P  =  0.027), all other virulence genes were not significantly associated with MRSA. Resistance to clindamycin (P  =  0.03), tetracycline (P  =  0.048), trimethoprim/sulfamethoxazole (P  =  0.038), and oxacillin (P  =  0.004) was significantly associated with MRSA. Survival assay showed MSSA having a lower median lifespan of 3 days than MRSA that had a median lifespan of 6 days. The difference in the killing time of MRSA and MSSA was significant (P < 0.001). Conclusion: While antibiotic resistance was significantly associated with MRSA, there was no preferential distribution of the virulence genes. The quicker killing potential of MSSA compared to MRSA suggests that carriage of virulence determinants per se does not determine pathogenicity in S. aureus. Pathogenicity is impacted by other factors, possibly antibiotic resistance. PMID:25319852

Survival of human-associated bacteria in SLS

NASA Astrophysics Data System (ADS)

Fu, Yuming; Tikhomirov, Alexander A.; Nickolay Manukovsky, D..; Khizhnyak, Sergey; Kovalev, Vladimir

2016-07-01

Management of microbial communities to minimize the potential for risk to the crew and to the plants to be used for supporting the crew is an essential component of successful bioregenerative life support systems (BLSS). Previously it was shown that soil-like substrate (SLS), obtained as a result of bioconversion of non-edible plant biomass in the higher plants based BLSS, demonstrates strong anti-fungal activity against soil-borne plant pathogens (Nesterenko et al., 2009). The present study is devoted to the estimation of anti-bacterial activity of SLS against gram-negative (presented with Escherichia coli) and gram-positive (presented with Staphylococcus aureus) human-associated bacteria, both of which belong to the group of opportunistic pathogen. In vitro effects of different types of SLS on E. coli and S. aureus and in situ survival curves of the bacteria with corresponding math models are presented. Additionally we have examined the influence of community richness (the indigenous community of SLS) on the ability of introduced human-associated bacteria to persist within SLS. The work was carried out within the frames of the state task on the subject No 56.1.4 of the Basic Research Program (Section VI) of Russian State Academies for 2013-2020.

Haem Recognition By a Staphylococcus Aureus NEAT Domain

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

Grigg, J.C.; Vermeiren, C.; Heinrichs, D.E.

2009-06-01

Successful pathogenic organisms have developed mechanisms to thrive under extreme levels of iron restriction. Haem-iron represents the largest iron reservoir in the human body and is a significant source of iron for some bacterial pathogens. NEAT (NEAr Transporter) domains are found exclusively in a family of cell surface proteins in Gram-positive bacteria. Many NEAT domain-containing proteins, including IsdA in Staphylococcus aureus, are implicated in haem binding. Here, we show that overexpression of IsdA in S. aureus enhances growth and an inactivation mutant of IsdA has a growth defect, compared with wild type, when grown in media containing haem as themore » sole iron source. Furthermore, the haem-binding property of IsdA is contained within the NEAT domain. Crystal structures of the apo-IsdA NEAT domain and in complex with haem were solved and reveal a clathrin adapter-like beta-sandwich fold with a large hydrophobic haem-binding pocket. Haem is bound with the propionate groups directed at the molecular surface and the iron is co-ordinated solely by Tyr(166). The phenol groups of Tyr(166) and Tyr(170) form an H-bond that may function in regulating haem binding and release. An analysis of IsdA structure-sequence alignments indicate that conservation of Tyr(166) is a predictor of haem binding by NEAT domains.« less

LukMF′ is the major secreted leukocidin of bovine Staphylococcus aureus and is produced in vivo during bovine mastitis

PubMed Central

Vrieling, Manouk; Boerhout, Eveline M.; van Wigcheren, Glenn F.; Koymans, Kirsten J.; Mols-Vorstermans, Tanja G.; de Haas, Carla J. C.; Aerts, Piet C.; Daemen, Ineke J. J. M.; van Kessel, Kok P. M.; Koets, Ad P.; Rutten, Victor P. M. G.; Nuijten, Piet J.M.; van Strijp, Jos A. G.; Benedictus, Lindert

2016-01-01

Staphylococcus aureus is a major human and animal pathogen and a common cause of mastitis in cattle. S. aureus secretes several leukocidins that target bovine neutrophils, crucial effector cells in the defence against bacterial pathogens. In this study, we investigated the role of staphylococcal leukocidins in the pathogenesis of bovine S. aureus disease. We show that LukAB, in contrast to the γ-hemolysins, LukED, and LukMF′, was unable to kill bovine neutrophils, and identified CXCR2 as a bovine receptor for HlgAB and LukED. Furthermore, we assessed functional leukocidin secretion by bovine mastitis isolates and observed that, although leukocidin production was strain dependent, LukMF′ was most abundantly secreted and the major toxin killing bovine neutrophils. To determine the role of LukMF′ in bovine mastitis, cattle were challenged with high (S1444) or intermediate (S1449, S1463) LukMF′-producing isolates. Only animals infected with S1444 developed severe clinical symptoms. Importantly, LukM was produced in vivo during the course of infection and levels in milk were associated with the severity of mastitis. Altogether, these findings underline the importance of LukMF′ as a virulence factor and support the development of therapeutic approaches targeting LukMF′ to control S. aureus mastitis in cattle. PMID:27886237

Design, synthesis and antibacterial evaluation of honokiol derivatives.

PubMed

Wu, Bo; Fu, Su-Hong; Tang, Huan; Chen, Kai; Zhang, Qiang; Peng, Ai-Hua; Ye, Hao-Yu; Cheng, Xing-Jun; Lian, Mao; Wang, Zhen-Ling; Chen, Li-Juan

2018-02-15

Staphylococcus aureus is a major and dangerous human pathogen that causes a range of clinical manifestations of varying severity, and is the most commonly isolated pathogen in the setting of skin and soft tissue infections, pneumonia, suppurative arthritis, endovascular infections, foreign-body associated infections, septicemia, osteomyelitis, and toxic shocksyndrome. Honokiol, a pharmacologically active natural compound derived from the bark of Magnolia officinalis, has antibacterial activity against Staphylococcus aureus which provides a great inspiration for the discovery of potential antibacterial agents. Herein, honokiol derivatives were designed, synthesized and evaluated for their antibacterial activity by determining the minimum inhibitory concentration (MIC) against S. aureus ATCC25923 and Escherichia coli ATCC25922 in vitro. 7c exhibited better antibacterial activity than other derivatives and honokiol. The structure-activity relationships indicated piperidine ring with amino group is helpful to improve antibacterial activity. Further more, 7c showed broad spectrum antibacterial efficiency against various bacterial strains including eleven gram-positive and seven gram-negative species. Time-kill kinetics against S. aureus ATCC25923 in vitro revealed that 7c displayed a concentration-dependent effect and more rapid bactericidal kinetics better than linezolid and vancomycin with the same concentration. Gram staining assays of S. aureus ATCC25923 suggested that 7c could destroy the cell walls of bacteria at 1×MIC and 4×MIC. Copyright © 2017. Published by Elsevier Ltd.

Isolation and characterization of three benzylisoquinoline alkaloids from Thalictrum minus L. and their antibacterial activity against bovine mastitis.

PubMed

Mushtaq, Saleem; Rather, Muzafar Ahmad; Qazi, Parvaiz H; Aga, Mushtaq A; Shah, Aabid Manzoor; Shah, Aiyatullah; Ali, Md Niamat

2016-12-04

The roots of Thalictrum minus are traditionally used in the treatment of inflammation and infectious diseases such as bovine mastitis. However, there are no reports available in literature till date regarding the antibacterial studies of T. minus against bovine mastitis. The present study was undertaken to evaluate the antibacterial potential of crude extract of T. minus (root) and some of its isolated constituents against bovine mastitis in order to scientifically validate its traditional use. A total of three alkaloid compounds were isolated from the DCM: MeOH extract of roots of T. minus using silica gel column chromatography. Structural elucidation of the isolated compounds was done by using spectroscopic techniques like mass spectrometry and NMR spectroscopy. Pathogens were isolated from cases of bovine mastitis and identified by using 16S rRNA gene sequencing. The broth micro-dilution method was used to evaluate the antibacterial activities of DCM: MeOH extract and isolated compounds against mastitis pathogens. The three isolated compounds were identified as benzylisoquinoline alkaloids (1) 5'-Hydroxythalidasine, (2) Thalrugosaminine and (3) O-Methylthalicberine. Compounds (2) and (3) are reported for the first time from the roots of T. minus. Five mastitis pathogens viz., Staphylococcus xylosus, Staphylococcus lentus, Staphylococcus equorum, Enterococcus faecalis and Pantoea agglomerans were identified on the basis of sequence analysis of isolates using the nucleotide BLAST algorithm. This study reports for the first time the isolation and molecular characterization of mastitis pathogens from Kashmir valley, India. The DCM: MeOH extract exhibited broad spectrum antibacterial activities that varied between the bacterial species (MIC=250-500µg/ml). 5'-Hydroxythalidasine and Thalrugosaminine showed promising antibacterial activity with MIC values of 64-128µg/ml while Staphylococcus species were found to be the most sensitive strains. The antibacterial activities of the DCM: MeOH extract and isolated compounds support the traditional use of T. minus in the treatment of bovine mastitis. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Effect of starter cultures on survival of Listeria monocytogenes in Čajna sausage

NASA Astrophysics Data System (ADS)

Bošković, M.; Tadić, V.; Đorđević, J.; Glišić, M.; Lakićević, B.; Dimitrijević, M.; Baltić, M. Ž.

2017-09-01

The aim of the study was to evaluate the survival of Listeria monocytogenes during the production of Čajna sausage with short maturation time. Sausage batter was inoculated with three different serotypes 4b and serotype 1/2a of L. monocytogenes. Control sausages were without any starter culture added; the second batch was inoculated with strains of Lactobacillus sakei, Staphylococcus carnosus and Staphylococcus xylosus, and the third batch was inoculated with strains of Debaryomyces hansenii, Lactobacillus sakei, Pediococcus acidilactici, Pediococcus pentosaceus, Staphylococcus carnosus and Staphylococcus xylosus. After 18 days of ripening, L. monocytogenes was not detected in any of the sausages, but during this fermentation and drying, the numbers of this pathogen was lower in the sausages inoculated with starter cultures.

Characterization of a novel composite staphylococcal cassette chromosome mec (SCCmec-SCCcad/ars/cop) in the neonatal sepsis-associated Staphylococcus capitis pulsotype NRCS-A.

PubMed

Martins Simões, P; Rasigade, J-P; Lemriss, H; Butin, M; Ginevra, C; Lemriss, S; Goering, R V; Ibrahimi, A; Picaud, J C; El Kabbaj, S; Vandenesch, F; Laurent, F

2013-12-01

Multiresistant Staphylococcus capitis pulsotype NRCS-A has been reported to be a major pathogen causing nosocomial bacteremia in preterm infants. We report that the NRCS-A strain CR01 harbors a novel 60.9-kb composite staphylococcal cassette chromosome mec (SCCmec) element, composed of an SCCmec with strong homologies to Staphylococcus aureus ST398 SCCmec and of an SCCcad/ars/cop harboring resistance genes for cadmium, arsenic, and copper. Whole-genome-based comparisons of published S. capitis strains suggest that strain CR01 acquired the two elements independently.

Identification of Emerging Human Mastitis Pathogens by MALDI-TOF and Assessment of Their Antibiotic Resistance Patterns

PubMed Central

Marín, María; Arroyo, Rebeca; Espinosa-Martos, Irene; Fernández, Leónides; Rodríguez, Juan M.

2017-01-01

Lactational mastitis constitutes one of the main causes of undesired weaning, depriving the mother–infant pair from the benefits of breastfeeding; therefore, this condition should be considered a relevant public health issue. The role of specific microorganisms remains unclear since human milk cultures and antibiotic susceptibility testing (AST) are not routinely performed, despite the fact that this would be key to ensure an early and effective diagnosis and treatment. The objective of this study was to describe the culturable microbial diversity in 647 milk samples from breastfeeding women with clinical symptoms of mastitis by Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF) VITEK MS technology and to analyze the antimicrobial susceptibility profiles of a collection of isolates from these samples by the VITEK 2 AST system. Staphylococcus epidermidis was the most common species isolated from mastitis samples (87.6%), while Staphylococcus aureus was detected in 22.1%. Streptococci constituted the second (68.6%) most prevalent bacterial group, with Streptococcus mitis/oralis, Streptococcus salivarius, and Streptococcus parasanguinis detected with frequencies of 40.8, 36.8, and 14.4%, respectively. The antibiotic susceptibility profiles of 642 staphylococcal isolates indicated a remarkable resistance to benzylpenicillin (88.3%) and erythromycin (67.3%) with differences between species. A high percentage of Staphylococcus isolates were resistant to at least one antibiotic (Staphylococcus hominis, 100%; S. epidermidis, 98.2%; S. aureus, 92.9%; Staphylococcus lugdunensis, 90.5%) and the percentage of multidrug-resistance (MDR) isolates was noticeable (S. hominis, 81%; S. epidermidis, 64.4%; S. aureus, 11.5%; S. lugdunensis, 10.5%). In relation to streptococcal isolates (n = 524), AST revealed high or moderate percentages of resistance to erythromycin (68.7%), benzylpenicillin (63.7%), ampicillin (51.5%), and tetracycline (30.8%). Antibiotic resistance to at least one antibiotic was detected in 97.6% of S. parasanguinis, 92.6% of S. salivarius, 83.3% of S. mitis/oralis, and 72.4% of Streptococcus vestibularis isolates. A significant number of MDR streptococcal isolates was also found (S. parasanguinis, 51.2%; S. salivarius, 39.3%; S. mitis/oralis, 34.6%; and S. vestibularis, 19%). The results highlight the important role of coagulase-negative staphylococci and streptococci as human mastitis-causing agents. Moreover, the high rates of antimicrobial resistance among these microorganisms must be contemplated as an issue of clinical relevance in relation to treatment options. PMID:28747897

Distribution of non-aureus staphylococci species in udder quarters with low and high somatic cell count, and clinical mastitis.

PubMed

Condas, Larissa A Z; De Buck, Jeroen; Nobrega, Diego B; Carson, Domonique A; Roy, Jean-Philippe; Keefe, Greg P; DeVries, Trevor J; Middleton, John R; Dufour, Simon; Barkema, Herman W

2017-07-01

The effect of non-aureus staphylococci (NAS) in bovine mammary health is controversial. Overall, NAS intramammary infections (IMI) increase somatic cell count (SCC), with an effect categorized as mild, mostly causing subclinical or mild to moderate clinical mastitis. However, based on recent studies, specific NAS may affect the udder more severely. Some of these apparent discrepancies could be attributed to the large number of species that compose the NAS group. The objectives of this study were to determine (1) the SCC of quarters infected by individual NAS species compared with NAS as a group, culture-negative, and major pathogen-infected quarters; (2) the distribution of NAS species isolated from quarters with low SCC (<200,000 cells/mL) and high SCC (≥200,000 cells/mL), and clinical mastitis; and (3) the prevalence of NAS species across quarters with low and high SCC. A total of 5,507 NAS isolates, 3,561 from low SCC quarters, 1,873 from high SCC quarters, and 73 from clinical mastitis cases, were obtained from the National Cohort of Dairy Farms of the Canadian Bovine Mastitis Research Network. Of quarters with low SCC, high SCC, or clinical mastitis, 7.6, 18.5, and 4.3% were NAS positive, respectively. The effect of NAS IMI on SCC was estimated using mixed-effect linear regression; prevalence of NAS IMI was estimated using Bayesian analyses. Mean SCC of NAS-positive quarters was 70,000 cells/mL, which was higher than culture-negative quarters (32,000 cells/mL) and lower than major pathogen-positive quarters (129,000 to 183,000 cells/mL). Compared with other NAS species, SCC was highest in quarters positive for Staphylococcus capitis, Staphylococcus gallinarum, Staphylococcus hyicus, Staphylococcus agnetis, or Staphylococcus simulans. In NAS-positive quarters, Staphylococcus xylosus (12.6%), Staphylococcus cohnii (3.1%), and Staphylococcus equorum (0.6%) were more frequently isolated from quarters with low SCC than other NAS species, whereas Staphylococcus sciuri (14%) was most frequently isolated from clinical mastitis cases. Finally, in NAS-positive quarters, Staphylococcus chromogenes, S. simulans, Staphylococcus epidermidis, and Staphylococcus haemolyticus were isolated with similar frequency from among low SCC and high SCC quarters and clinical mastitis cases. Staphylococcus chromogenes, S. simulans, S. xylosus, S. haemolyticus, S. epidermidis, S. agnetis, Staphylococcus arlettae, S. capitis, S. gallinarum, S. sciuri, and Staphylococcus warneri were more prevalent in high than in low SCC quarters. Because the NAS are a large, heterogeneous group, considering them as a single group rather than at the species, or even subspecies level, has undoubtedly contributed to apparent discrepancies among studies as to their distribution and importance in IMI and mastitis. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Within-herd prevalence thresholds for herd-level detection of mastitis pathogens using multiplex real-time PCR in bulk tank milk samples.

PubMed

Soltau, J B; Einax, E; Klengel, K; Katholm, J; Failing, K; Wehrend, A; Donat, K

2017-10-01

The objective of the study was to assess the value of quantitative multiplex real-time PCR examination of bulk tank milk samples for bovine mastitis pathogens as a tool for herd level diagnosis. Using a logistic regression model, this study is aimed at calculating the threshold level of the apparent within-herd prevalence as determined by quarter milk sample cultivation of all lactating cows, thus allowing the detection of a herd positive for a specific pathogen within certain probability levels. A total of 6,335 quarter milk samples were collected and cultured from 1,615 cows on 51 farms in Germany. Bulk tank milk samples were taken from each farm and tested by bacterial culture as well as the commercial PCR assay Mastit 4A (DNA Diagnostic A/S, Risskov, Denmark) identifying Staphylococcus aureus, Streptococcus dysgalactiae, Streptococcus agalactiae, and Streptococcus uberis. In addition, PCR was performed on pooled herd milk samples containing milk aliquots from all lactating cows in each of the 51 herds. Only 1 out of the 51 herds was found PCR positive for Streptococcus agalactiae in bulk tank and pooled herd milk samples, and cultured quarter milk samples. Spearman's rank correlations between the cycle threshold value of bulk tank milk PCR and the apparent within-herd prevalence were calculated in regard to Staphylococcus aureus, Streptococcus dysgalactiae, and Streptococcus uberis. For these pathogens, significant correlations were found. If 1 bulk tank milk sample per herd was tested, the estimated within-herd prevalence thresholds for 90% probability of detection were 27.6% for Staphylococcus aureus, 9.2% for Streptococcus dysgalactiae, and 13.8% for Streptococcus uberis on the cow level. On the quarter level, the within-herd prevalence had to be at least 32.6% for Staphylococcus aureus, 1.7% for Streptococcus dysgalactiae, and 4.3% for Streptococcus uberis to detect a herd as positive using a single bulk milk sample. The results indicate that mastitis pathogens in bulk tank milk can be identified by the applied PCR assay. Bulk tank milk examination is not a reliable tool for the identification of the named pathogens by single testing, but might be a valuable monitoring tool when used frequently with repeated testing. Furthermore, this approach could be a useful monitoring tool for detecting new pathogen occurrence in the herd. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Coagulase-Negative Staphylococci in Human Milk From Mothers of Preterm Compared With Term Neonates.

PubMed

Soeorg, Hiie; Metsvaht, Tuuli; Eelmäe, Imbi; Metsvaht, Hanna Kadri; Treumuth, Sirli; Merila, Mirjam; Ilmoja, Mari-Liis; Lutsar, Irja

2017-05-01

Human milk is the preferred nutrition for neonates and a source of bacteria. Research aim: The authors aimed to characterize the molecular epidemiology and genetic content of staphylococci in the human milk of mothers of preterm and term neonates. Staphylococci were isolated once per week in the 1st month postpartum from the human milk of mothers of 20 healthy term and 49 preterm neonates hospitalized in the neonatal intensive care unit. Multilocus variable-number tandem-repeats analysis and multilocus sequence typing were used. The presence of the mecA gene, icaA gene of the ica-operon, IS 256, and ACME genetic elements was determined by PCR. The human milk of mothers of preterm compared with term neonates had higher counts of staphylococci but lower species diversity. The human milk of mothers of preterm compared with term neonates more often contained Staphylococcus epidermidis mecA (32.7% vs. 2.6%), icaA (18.8% vs. 6%), IS 256 (7.9% vs. 0.9%), and ACME (15.4% vs. 5.1%), as well as Staphylococcus haemolyticus mecA (90.5% vs. 10%) and IS 256 (61.9% vs. 10%). The overall distribution of multilocus variable-number tandem-repeats analysis (MLVA) types and sequence types was similar between the human milk of mothers of preterm and term neonates, but a few mecA-IS 256-positive MLVA types colonized only mothers of preterm neonates. Maternal hospitalization within 1 month postpartum and the use of an arterial catheter or antibacterial treatment in the neonate increased the odds of harboring mecA-positive staphylococci in human milk. Limiting exposure of mothers of preterm neonates to the hospital could prevent human milk colonization with more pathogenic staphylococci.

Bacteriological profiling of diphenylureas as a novel class of antibiotics against methicillin-resistant Staphylococcus aureus

PubMed Central

Younis, Waleed; Ezzat, Hany G.; Peters, Christine E.; AbdelKhalek, Ahmed; Cooper, Bruce; Pogliano, Kit; Pogliano, Joe; Mayhoub, Abdelrahman S.; Seleem, Mohamed N.

2017-01-01

Bacterial resistance to antibiotics remains an imposing global public health challenge. Of the most serious pathogens, methicillin-resistant Staphylococcus aureus (MRSA) is problematic given strains have emerged that exhibit resistance to several antibiotic classes including β-lactams and agents of last resort such as vancomycin. New antibacterial agents composed of unique chemical scaffolds are needed to counter this public health challenge. The present study examines two synthetic diphenylurea compounds 1 and 2 that inhibit growth of clinically-relevant isolates of MRSA at concentrations as low as 4 µg/mL and are non-toxic to human colorectal cells at concentrations up to 128 μg/mL. Both compounds exhibit rapid bactericidal activity, completely eliminating a high inoculum of MRSA within four hours. MRSA mutants exhibiting resistance to 1 and 2 could not be isolated, indicating a low likelihood of rapid resistance emerging to these compounds. Bacterial cytological profiling revealed the diphenylureas exert their antibacterial activity by targeting bacterial cell wall synthesis. Both compounds demonstrate the ability to resensitize vancomycin-resistant Staphylococcus aureus to the effect of vancomycin. The present study lays the foundation for further investigation and development of diphenylurea compounds as a new class of antibacterial agents. PMID:28797064

Dormant Cells of Staphylococcus aureus Are Resuscitated by Spent Culture Supernatant

PubMed Central

Pascoe, Ben; Dams, Lucy; Wilkinson, Tom S.; Harris, Llinos G.; Bodger, Owen; Mack, Dietrich; Davies, Angharad P.

2014-01-01

We describe the first in vitro model of dormancy in Staphylococcus aureus, showing that cells are generated which can be resuscitated by addition of spent medium supernatant taken from cultures of the same organism. Over 30 days, culturable counts in dormant cultures of S. aureus SH1000 fell from 106–107 cfu/ml to <10 cfu/ml as measured by the Most Probable Number method in liquid culture, while total counts as determined by microscopy, and supported by data from RT-qPCR, remained around 106–107 cells/ml. Supplementing cultures with 25–50% spent medium resulted in a >600-fold increase in bacterial growth. Resuscitation was a specific effect, greatly reduced by boiling or addition of trypsin to the spent supernatant. Supernatant also effected a reduction in lag phase of dormant cultures. SEM demonstrated the presence of small coccoid cells in dormant cultures. The results are similar to those seen with resuscitation promoting factors (Rpfs) in actinobacteria. This is the first time resuscitation has been demonstrated in Staphylococcus aureus, which is an important human pathogen. A better understanding of control and reactivation of dormant cells could lead to major improvements in managing staphylococcal infections; resuscitation could be an important step in restoring susceptibility to antibiotic treatment. PMID:24523858

Population structure and antimicrobial profile of Staphylococcus aureus strains associated with bovine mastitis in China.

PubMed

Zhang, Lili; Li, Yuchen; Bao, Hongduo; Wei, Ruicheng; Zhou, Yan; Zhang, Hui; Wang, Ran

2016-08-01

Staphylococcus aureus is a significant bacterial pathogen associated with bovine mastitis. The aim of the present study was to investigate and characterize of S. aureus strains isolated from the milk of cows suffering from mastitis in the mid-east of China. Among the 200 milk samples analyzed, 58 were positive for S. aureus, of these isolates, 11 isolates were methicillin-resistant Staphylococcus aureus (MRSA). All of the 58 S. aureus strains were classified in agr group I, while seven different sequence type (ST) patterns were identified and among them the most common was ST630 followed by ST188. All of the S. aureus isolates belonging to ST630 were resistant to more than four antimicrobials, and 22.2% of isolates belonging to ST188 were resistant to eight antimicrobials. Interestingly, while strong biofilm producers demonstrated higher resistance to multiple antimicrobials, they exhibited lower intracellular survival rates. The results of this study illustrated the distribution, antimicrobial susceptibility profiles, genotype, and the ability of biofilm production and mammary epithelial cells invasion of these S. aureus isolates. This study can provide the basis for the development of a disease prevention program in dairy farms to reduce the potential risk in both animal and human health. Copyright © 2016 Elsevier Ltd. All rights reserved.

In vitro transfer of methicillin resistance determinants mecA from methicillin resistant Staphylococcus aureus (MRSA) to methicillin susceptible Staphylococcus aureus (MSSA).

PubMed

Bitrus, Asinamai Athliamai; Zunita, Zakaria; Bejo, Siti Khairani; Othman, Sarah; Nadzir, Nur Adilah Ahmad

2017-04-04

Staphylococcus aureus more than any other human pathogen is a better model for the study of the adaptive evolution of bacterial resistance to antibiotics, as it has demonstrated a remarkable ability in its response to new antibiotics. This study was designed to investigate the in vitro transfer of mecA gene from methicillin resistant S. aureus to methicillin susceptible S. aureus. The recipient transconjugants were resistant to erythromycin, cefpodoxime and were mecA positive. PCR amplification of mecA after mix culture plating on Luria Bertani agar containing 100 μg/mL showed that 75% of the donor and 58.3% of the recipient transconjugants were mecA positive. Additionally, 61.5% of both the donor cells and recipient transconjugants were mecA positive, while 46.2% and 41.75% of both donor and recipient transconjugants were mecA positive on LB agar containing 50 μg/mL and 30 μg/mL respectively. In this study, the direction of transfer of phenotypic resistance as well as mecA was observed to have occurred from the donor to the recipient strains. This study affirmed the importance of horizontal transfer events in the dissemination of antibiotics resistance among different strains of MRSA.

Antimicrobial Activities of Bacteria Associated with the Brown Alga Padina pavonica

PubMed Central

Ismail, Amel; Ktari, Leila; Ahmed, Mehboob; Bolhuis, Henk; Boudabbous, Abdellatif; Stal, Lucas J.; Cretoiu, Mariana Silvia; El Bour, Monia

2016-01-01

Macroalgae belonging to the genus Padina are known to produce antibacterial compounds that may inhibit growth of human- and animal pathogens. Hitherto, it was unclear whether this antibacterial activity is produced by the macroalga itself or by secondary metabolite producing epiphytic bacteria. Here we report antibacterial activities of epiphytic bacteria isolated from Padina pavonica (Peacocks tail) located on northern coast of Tunisia. Eighteen isolates were obtained in pure culture and tested for antimicrobial activities. Based on the 16S rRNA gene sequences the isolates were closely related to Proteobacteria (12 isolates; 2 Alpha- and 10 Gammaproteobacteria), Firmicutes (4 isolates) and Actinobacteria (2 isolates). The antimicrobial activity was assessed as inhibition of growth of 12 species of pathogenic bacteria (Aeromonas salmonicida, A. hydrophila, Enterobacter xiangfangensis, Enterococcus faecium, Escherichia coli, Micrococcus sp., Salmonella typhimurium, Staphylococcus aureus, Streptococcus sp., Vibrio alginoliticus, V. proteolyticus, V. vulnificus) and one pathogenic yeast (Candida albicans). Among the Firmicutes, isolate P8, which is closely related to Bacillus pumilus, displayed the largest spectrum of growth inhibition of the pathogenic bacteria tested. The results emphasize the potential use of P. pavonica associated antagonistic bacteria as producers of novel antibacterial compounds. PMID:27462308

Antibacterial potential of Calotropis procera (flower) extract against various pathogens.

PubMed

Ali, Abid; Ansari, Asma; Qader, Shah Ali Ul; Mumtaz, Majid; Saied, Sumayya; Mahboob, Tabassum

2014-09-01

Increased bacterial resistance towards commonly used antibiotics has become a debated issue all over the world in a last few decades. Due to this, consumer demand towards natural anti-microbial agents is increasing day by day. Natural anti-microbial agents have gained enormous attention as an alternative therapeutic agent in pharmaceutical industry. Current study is an effort to explore and identify a bactericidal potential of various solvent extracts of Calotropis procera flower. Flowers of C. procera were extracted with hexane, butanol, ethyl acetate and aqua to evaluate the antibacterial activity by agar well diffusion method against the various human pathogens. The microorganisms used in this study includes Salmonella typhi, Escherichia coli (O157:H7), Micrococcus luteus KIBGE-IB20 (Gen Bank accession: JQ250612) and methicillin resistant Staphylococcus aureus (MRSA) KIBGE-IB23 (Gen Bank accession: KC465400). Zones of inhibition were observed against all four pathogenic strains. Fraction soluble in hexane showed broad spectrum of inhibition against all the studied pathogens. However, fractions soluble in ethyl acetate inhibited the growth of E. coli, MRSA, and M. luteus. In case of butanol and aqueous extracts only growth of M. luteus was inhibited. Results revealed that the flower extracts of C. procera have a potential to be used as an antibacterial agent against these pathogenic organisms.

Synthesis of nano-cuboidal gold particles for effective antimicrobial property against clinical human pathogens.

PubMed

Murphin Kumar, Paskalis Sahaya; MubarakAli, Davoodbasha; Saratale, Rijuta Ganesh; Saratale, Ganesh Dattatraya; Pugazhendhi, Arivalagan; Gopalakrishnan, Kumar; Thajuddin, Nooruddin

2017-12-01

Algae could offer a potential source of fine chemicals, pharmaceuticals and biofuels. In this study, a green synthesis of dispersed cuboidal gold nanoparticles (AuNPs) was achieved using red algae, Gelidium amansii reacted with HAuCl 4 . It was found to be 4-7 nm sized cubical nanoparticles with aspect ratio of 1.4 were synthesized using 0.5 mM of HAuCl 4 by HRSEM analysis. The crystalline planes (111), (200), (220), (311) and elemental signal of gold was observed by XRD and EDS respectively. The major constitutes, galactose and 3,6-anhydrogalactose in the alga played a critical role in the synthesis of crystalline AuNPs with cubical dimension. Further, the antibacterial potential of synthesized AuNPs was tested against human pathogens, Escherichia coli and Staphylococcus aureus. The synthesized AuNPs found biocompatible up to 100 ppm and high concentration showed an inhibition against cancer cell. This novel report could be helped to exploration of bioresources to material synthesis for the application of biosensor and biomedical application. Copyright © 2017 Elsevier Ltd. All rights reserved.

Green synthesis of silver nanoparticles using marine algae Caulerpa racemosa and their antibacterial activity against some human pathogens

NASA Astrophysics Data System (ADS)

Kathiraven, T.; Sundaramanickam, A.; Shanmugam, N.; Balasubramanian, T.

2015-04-01

We present the synthesis and antibacterial activity of silver nanoparticles using Caulerpa racemosa, a marine algae. Fresh C. racemosa was collected from the Gulf of Mannar, Southeast coast of India. The seaweed extract was used for the synthesis of AgNO3 at room temperature. UV-visible spectrometry study revealed surface plasmon resonance at 413 nm. The characterization of silver nanoparticle was carried out using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and transmission electron microscope (TEM). FT-IR measurements revealed the possible functional groups responsible for reduction and stabilization of the nanoparticles. X-ray diffraction analysis showed that the particles were crystalline in nature with face-centered cubic geometry.TEM micrograph has shown the formation of silver nanoparticles with the size in the range of 5-25 nm. The synthesized AgNPs have shown the best antibacterial activity against human pathogens such as Staphylococcus aureus and Proteus mirabilis. The above eco-friendly synthesis procedure of AgNPs could be easily scaled up in future for the industrial and therapeutic needs.

Host plasma proteins on the surface of pathogenic Trichomonas vaginalis.

PubMed

Peterson, K M; Alderete, J F

1982-08-01

Sodium dodecyl sulfate-gel electrophoresis and fluorography and fluorography technology revealed that pathogenic Trichomonas vaginalis was able to acquire numerous loosely associated plasma proteins during incubation in normal human plasma. These proteins were readily removed by repeated washing of the parasite in phosphate-buffered saline. Plasma proteins avidly bound to the surface of T. vaginalis were also detected using a highly sensitive and specific agglutination assay with protein A-bearing Staphylococcus aureus pretreated with monospecific antiserum directed against individual human serum proteins. These avidly associated plasma proteins could not be removed by repeated washing in phosphate-buffered saline or by treatment of washed, live organisms with surface-modifying reagents such as trypsin and periodate. A combined radioimmunoprecipitation-gel electrophoresis-fluorography methodology indicated that parasite biosynthesis of hostlike macromolecules was not responsible for the observed agglutination and reinforced the idea of trichosomal acquisition of plasma components. Finally, incubation of trichomonads with plasma in various buffers at different pH values did not alter the agglutination patterns. These and other data suggest that specific membrane sites trichomonal binding of host proteins. The biological significance of our results is discussed.

Antibiofilm Activity of the Brown Alga Halidrys siliquosa against Clinically Relevant Human Pathogens

PubMed Central

Busetti, Alessandro; Thompson, Thomas P.; Tegazzini, Diana; Megaw, Julianne; Maggs, Christine A.; Gilmore, Brendan F.

2015-01-01

The marine brown alga Halidrys siliquosa is known to produce compounds with antifouling activity against several marine bacteria. The aim of this study was to evaluate the antimicrobial and antibiofilm activity of organic extracts obtained from the marine brown alga H. siliquosa against a focused panel of clinically relevant human pathogens commonly associated with biofilm-related infections. The partially fractionated methanolic extract obtained from H. siliquosa collected along the shores of Co. Donegal; Ireland; displayed antimicrobial activity against bacteria of the genus Staphylococcus; Streptococcus; Enterococcus; Pseudomonas; Stenotrophomonas; and Chromobacterium with MIC and MBC values ranging from 0.0391 to 5 mg/mL. Biofilms of S. aureus MRSA were found to be susceptible to the algal methanolic extract with MBEC values ranging from 1.25 mg/mL to 5 mg/mL respectively. Confocal laser scanning microscopy using LIVE/DEAD staining confirmed the antimicrobial nature of the antibiofilm activity observed using the MBEC assay. A bioassay-guided fractionation method was developed yielding 10 active fractions from which to perform purification and structural elucidation of clinically-relevant antibiofilm compounds. PMID:26058011

Real-Time Imaging of the Bacillithiol Redox Potential in the Human Pathogen Staphylococcus aureus Using a Genetically Encoded Bacilliredoxin-Fused Redox Biosensor.

PubMed

Loi, Vu Van; Harms, Manuela; Müller, Marret; Huyen, Nguyen Thi Thu; Hamilton, Chris J; Hochgräfe, Falko; Pané-Farré, Jan; Antelmann, Haike

2017-05-20

Bacillithiol (BSH) is utilized as a major thiol-redox buffer in the human pathogen Staphylococcus aureus. Under oxidative stress, BSH forms mixed disulfides with proteins, termed as S-bacillithiolation, which can be reversed by bacilliredoxins (Brx). In eukaryotes, glutaredoxin-fused roGFP2 biosensors have been applied for dynamic live imaging of the glutathione redox potential. Here, we have constructed a genetically encoded bacilliredoxin-fused redox biosensor (Brx-roGFP2) to monitor dynamic changes in the BSH redox potential in S. aureus. The Brx-roGFP2 biosensor showed a specific and rapid response to low levels of bacillithiol disulfide (BSSB) in vitro that required the active-site Cys of Brx. Dynamic live imaging in two methicillin-resistant S. aureus (MRSA) USA300 and COL strains revealed fast and dynamic responses of the Brx-roGFP2 biosensor under hypochlorite and hydrogen peroxide (H 2 O 2 ) stress and constitutive oxidation of the probe in different BSH-deficient mutants. Furthermore, we found that the Brx-roGFP2 expression level and the dynamic range are higher in S. aureus COL compared with the USA300 strain. In phagocytosis assays with THP-1 macrophages, the biosensor was 87% oxidized in S. aureus COL. However, no changes in the BSH redox potential were measured after treatment with different antibiotics classes, indicating that antibiotics do not cause oxidative stress in S. aureus. Conclusion and Innovation: This Brx-roGFP2 biosensor catalyzes specific equilibration between the BSH and roGFP2 redox couples and can be applied for dynamic live imaging of redox changes in S. aureus and other BSH-producing Firmicutes. Antioxid. Redox Signal. 26, 835-848.

Genomics of Staphylococcus

NASA Astrophysics Data System (ADS)

Lindsay, Jodi A.

The staphylococci are Gram-positive cocci that divide to form clusters that look like grapes. By 16S ribosomal sequencing, they are most closely related to the Gram-positive, low G+C content Bacillus-Lactobacillus-Staphylococcus genera (Woese, 1987). There are over 30 species of staphylococci identified, and they are typically found on the skin and mucous membranes of mammals. About a dozen species are frequently carried on humans, including Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus capitis, Staphylococcus hominis, Staphylococcus cohnii, Staphylococcus lugdunensis, Staphylococcus schleiferi, Staphylococcus saprophyticus, Staphylococcus simulans, Staphylococcus warneri and Staphylococcus xylosus.

In vitro selection of RNA aptamer specific to Salmonella typhimurium.

PubMed

Han, Seung Ryul; Lee, Seong-Wook

2013-06-28

Salmonella is a major foodborne pathogen that causes a variety of human diseases. Development of ligands directly and specifically binding to the Salmonella will be crucial for the rapid detection of, and thus for efficient protection from, the virulent bacteria. In this study, we identified a RNA aptamer-based ligand that can specifically recognize Salmonella Typhimurium through SELEX technology. To this end, we isolated and characterized an RNase-resistant RNA aptamer that bound to the OmpC protein of Salmonella Typhimurium with high specificity and affinity (Kd ~ 20 nM). Of note, the selected aptamer was found to specifically bind to Salmonella Typhimurium, but neither to Gram-positive bacteria (Staphylococcus aureus) nor to other Gram-negative bacteria (Escherichia coli O157:H7). This was evinced by aptamer-immobilized ELISA and aptamer-linked precipitation experiments. This Salmonella species-specific aptamer could be useful as a diagnostic ligand against pathogen-caused foodborne sickness.

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

Antimicrobial activity of cream incorporated with silver nanoparticles biosynthesized from Withania somnifera

PubMed Central

Marslin, Gregory; Selvakesavan, Rajendran K; Franklin, Gregory; Sarmento, Bruno; Dias, Alberto CP

2015-01-01

We report on the antimicrobial activity of a cream formulation of silver nanoparticles (AgNPs), biosynthesized using Withania somnifera extract. Aqueous extracts of leaves promoted efficient green synthesis of AgNPs compared to fruits and root extracts of W. somnifera. Biosynthesized AgNPs were characterized for their size and shape by physical-chemical techniques such as UV-visible spectroscopy, laser Doppler anemometry, transmission electron microscopy, scanning electron microscopy, atomic force microscopy, X-ray diffraction, and X-ray energy dispersive spectroscopy. After confirming the antimicrobial potential of AgNPs, they were incorporated into a cream. Cream formulations of AgNPs and AgNO3 were prepared and compared for their antimicrobial activity against human pathogens (Staphylococcus aureus, Pseudomonas aeruginosa, Proteus vulgaris, Escherichia coli, and Candida albicans) and a plant pathogen (Agrobacterium tumefaciens). Our results show that AgNP creams possess significantly higher antimicrobial activity against the tested organisms. PMID:26445537

Whole Genome Sequencing of Danish Staphylococcus argenteus Reveals a Genetically Diverse Collection with Clear Separation from Staphylococcus aureus.

PubMed

Hansen, Thomas A; Bartels, Mette D; Høgh, Silje V; Dons, Lone E; Pedersen, Michael; Jensen, Thøger G; Kemp, Michael; Skov, Marianne N; Gumpert, Heidi; Worning, Peder; Westh, Henrik

2017-01-01

Staphylococcus argenteus ( S. argenteus ) is a newly identified Staphylococcus species that has been misidentified as Staphylococcus aureus ( S. aureus ) and is clinically relevant. We identified 25 S. argenteus genomes in our collection of whole genome sequenced S. aureus . These genomes were compared to publicly available genomes and a phylogeny revealed seven clusters corresponding to seven clonal complexes. The genome of S. argenteus was found to be different from the genome of S. aureus and a core genome analysis showed that ~33% of the total gene pool was shared between the two species, at 90% homology level. An assessment of mobile elements shows flow of SCC mec cassettes, plasmids, phages, and pathogenicity islands, between S. argenteus and S. aureus . This dataset emphasizes that S. argenteus and S. aureus are two separate species that share genetic material.

Staphylococcus haemolyticus as an Important Hospital Pathogen and Carrier of Methicillin Resistance Genes

PubMed Central

Barros, E. M.; Ceotto, H.; Bastos, M. C. F.; dos Santos, K. R. N.

2012-01-01

Phenotypic and molecular methods were used to characterize the antibiotic resistance of 64 clinical isolates of Staphylococcus haemolyticus. By PCR of the mecA gene, 87% were found to be methicillin resistant. Approximately 55% harbored staphylococcal cassette chromosome mec element (SCCmec) type V, and only one SCCmec type IV. Many isolates (75%) displayed multiresistance, and pulsotype analysis showed a high diversity. PMID:21976766

New drugs for methicillin-resistant Staphylococcus aureus: an update.

PubMed

Kumar, Krishan; Chopra, Sidharth

2013-07-01

Methicillin-resistant Staphylococcus aureus (MRSA) remains a leading cause of bacterial infections worldwide, with a dwindling repertoire of effective antimicrobials active against it. This review aims to provide an update on novel anti-MRSA molecules currently under pre-clinical and clinical development, with emphasis on their mechanism of action. This review is limited to molecules that target the pathogen directly and does not detail immunomodulatory anti-infectives.

Microbiological Assessment of Moringa Oleifera Extracts and Its Incorporation in Novel Dental Remedies against Some Oral Pathogens

PubMed Central

Elgamily, Hanaa; Moussa, Amani; Elboraey, Asmaa; EL-Sayed, Hoda; Al-Moghazy, Marwa; Abdalla, Aboelfetoh

2016-01-01

AIM: To assess the antibacterial and antifungal potentials of different parts of Moringa oleifera plant using different extraction methods in attempts to formulate natural dental remedies from this plant. MATERIAL AND METHODS: Three solvents extracts (Ethanol, acetone, and ethyl acetate) of different parts of Egyptian Moringa tree were prepared and tested against oral pathogens: Staphylococcus aureus, Streptococcus mutans, and Candida albicans using disc diffusion method; As well as to incorporate the plant extract to formulate experimental toothpaste and mouthwash. The two dental remedies were assessed against the same microbial strains. Statistical analysis was performed using One-Way ANOVA test to compare the inhibition zone diameter and t-test. RESULTS: Ethanol extracts as well as leaves extracts demonstrated the highest significant mean inhibition zone values (P ≤ 0.05) against Staphylococcus aureus and Streptococcus mutans growth. However, all extracts revealed no inhibition zone against Candida albicans. For dental remedies, experimental toothpaste exhibited higher mean inhibition than the mouthwash against Staphylococcus aureus, Streptococcus mutans and only the toothpaste revealed antifungal effect against Candida albicans. CONCLUSION: The different extracts of different parts of Moringa showed an antibacterial effect against Staphylococcus aureus and Streptococcus mutans growth. The novel toothpaste of ethanolic leaves extract has antimicrobial and antifungal potential effects all selected strains. PMID:28028395

Alternative fluorescent labeling strategies for characterizing gram-positive pathogenic bacteria: Flow cytometry supported counting, sorting, and proteome analysis of Staphylococcus aureus retrieved from infected host cells.

PubMed

Hildebrandt, Petra; Surmann, Kristin; Salazar, Manuela Gesell; Normann, Nicole; Völker, Uwe; Schmidt, Frank

2016-10-01

Staphylococcus aureus is a Gram-positive opportunistic pathogen that is able to cause a broad range of infectious diseases in humans. Furthermore, S. aureus is able to survive inside nonprofessional phagocytic host cell which serve as a niche for the pathogen to hide from the immune system and antibiotics therapies. Modern OMICs technologies provide valuable tools to investigate host-pathogen interactions upon internalization. However, these experiments are often hampered by limited capabilities to retrieve bacteria from such an experimental setting. Thus, the aim of this study was to develop a labeling strategy allowing fast detection and quantitation of S. aureus in cell lysates or infected cell lines by flow cytometry for subsequent proteome analyses. Therefore, S. aureus cells were labeled with the DNA stain SYTO ® 9, or Vancomycin BODIPY ® FL (VMB), a glycopeptide antibiotic binding to most Gram-positive bacteria which was conjugated to a fluorescent dye. Staining of S. aureus HG001 with SYTO 9 allowed counting of bacteria from pure cultures but not in cell lysates from infection experiments. In contrast, with VMB it was feasible to stain bacteria from pure cultures as well as from samples of infection experiments. VMB can also be applied for histocytochemistry analysis of formaldehyde fixed cell layers grown on coverslips. Proteome analyses of S. aureus labeled with VMB revealed that the labeling procedure provoked only minor changes on proteome level and allowed cell sorting and analysis of S. aureus from infection settings with sensitivity similar to continuous gfp expression. Furthermore, VMB labeling allowed precise counting of internalized bacteria and can be employed for downstream analyses, e.g., proteomics, of strains not easily amendable to genetic manipulation such as clinical isolates. © 2016 International Society for Advancement of Cytometry. © 2016 International Society for Advancement of Cytometry.

Characterisation of nasal Staphylococcus delphini and Staphylococcus pseudintermedius isolates from healthy donkeys in Tunisia.

PubMed

Gharsa, H; Slama, K Ben; Gómez-Sanz, E; Gómez, P; Klibi, N; Zarazaga, M; Boudabous, A; Torres, C

2015-07-01

Staphylococcus intermedius group (SIG) bacteria can colonise the nares of some animals but are also emerging pathogens in humans and animals. To analyse SIG nasal carriage in healthy donkeys destined for food consumption in Tunisia and to characterise recovered isolates. Nasal swabs from 100 healthy donkeys were tested for SIG recovery, and isolates were identified by biochemical and molecular methods. Antimicrobial susceptibility of isolates was tested and detection of antimicrobial resistance and virulence genes was performed. Isolates were typed at the clonal level by multilocus sequence typing and SmaI pulsed-field gel electrophoresis. Staphylococcus delphini and Staphylococcus pseudintermedius (included in SIG) were obtained in 19% and 2% of the tested samples, respectively, and one isolate per sample was characterised. All isolates were meticillin susceptible and mecA negative. Most S. delphini and S. pseudintermedius isolates showed susceptibility to all antimicrobials tested, with the exception of 2 isolates resistant to tetracycline (tet(M) gene) or fusidic acid. The following toxin genes were identified (percentage of isolates): lukS-I (100%), lukF-I (9.5%), siet (100%), se-int (90%), seccanine (19%) and expA (9.5%). Thirteen different pulsed-field gel electrophoresis profiles were identified among the 21 SIG isolates. Additionally, the following 9 different sequence types (STs) were detected by multilocus sequence typing, 6 of them new: ST219 (6 isolates), ST12 (5 isolates), ST220 (3 isolates), ST13, ST50, ST193, ST196, ST218 and ST221 (one isolate each). Staphylococcus delphini and S. pseudintermedius are common nasal colonisers of donkeys, generally susceptible to the antimicrobials tested; nevertheless, these SIG isolates contain virulence genes, including the recently described exfoliative gene (expA) and several enterotoxin genes, with potential implications for public health. This is the first description of S. delphini in Tunisia. The Summary is available in Chinese - see Supporting information. © 2014 EVJ Ltd.

Detection of mecC-Positive Staphylococcus aureus (CC130-MRSA-XI) in Diseased European Hedgehogs (Erinaceus europaeus) in Sweden

PubMed Central

Monecke, Stefan; Gavier-Widen, Dolores; Mattsson, Roland; Rangstrup-Christensen, Lena; Lazaris, Alexandros; Coleman, David C.; Shore, Anna C.; Ehricht, Ralf

2013-01-01

Recently, a novel mec gene conferring beta-lactam resistance in Staphylococcus aureus has been discovered. This gene, mecC, is situated on a SCCmec XI element that has to date been identified in clonal complexes 49, 130, 425, 599 and 1943. Some of the currently known isolates have been identified from animals. This, and observations of mecA alleles that do not confer beta-lactam resistance, indicate that mec genes might have a reservoir in Staphylococcus species from animals. Thus it is important also to screen wildlife isolates for mec genes. Here, we describe mecC-positive Staphylococcus aureus (ST130-MRSA-XI) and the lesions related to the infection in two diseased free-ranging European hedgehogs (Erinaceus europaeus). One was found dead in 2003 in central Sweden, and suffered from S. aureus septicaemia. The other one, found on the island of Gotland in the Baltic Sea in 2011, showed a severe dermatitis and was euthanised. ST130-MRSA-XI isolates were isolated from lesions from both hedgehogs and were essentially identical to previously described isolates from humans. Both isolates carried the complete SCCmec XI element. They lacked the lukF-PV/lukS-PV and lukM/lukF-P83 genes, but harboured a gene for an exfoliative toxin homologue previously described from Staphylococcus hyicus, Staphylococcus pseudintermedius and other S. aureus of the CC130 lineage. To the best of our knowledge, these are the first reported cases of CC130-MRSA-XI in hedgehogs. Given that one of the samples was taken as early as 2003, this was the earliest detection of this strain and of mecC in Sweden. This and several other recent observations suggest that CC130 might be a zoonotic lineage of S. aureus and that SCCmec XI/mecC may have originated from animal pathogens. PMID:23776626

Detection of mecC-positive Staphylococcus aureus (CC130-MRSA-XI) in diseased European hedgehogs (Erinaceus europaeus) in Sweden.

PubMed

Monecke, Stefan; Gavier-Widen, Dolores; Mattsson, Roland; Rangstrup-Christensen, Lena; Lazaris, Alexandros; Coleman, David C; Shore, Anna C; Ehricht, Ralf

2013-01-01

Recently, a novel mec gene conferring beta-lactam resistance in Staphylococcus aureus has been discovered. This gene, mecC, is situated on a SCCmec XI element that has to date been identified in clonal complexes 49, 130, 425, 599 and 1943. Some of the currently known isolates have been identified from animals. This, and observations of mecA alleles that do not confer beta-lactam resistance, indicate that mec genes might have a reservoir in Staphylococcus species from animals. Thus it is important also to screen wildlife isolates for mec genes. Here, we describe mecC-positive Staphylococcus aureus (ST130-MRSA-XI) and the lesions related to the infection in two diseased free-ranging European hedgehogs (Erinaceus europaeus). One was found dead in 2003 in central Sweden, and suffered from S. aureus septicaemia. The other one, found on the island of Gotland in the Baltic Sea in 2011, showed a severe dermatitis and was euthanised. ST130-MRSA-XI isolates were isolated from lesions from both hedgehogs and were essentially identical to previously described isolates from humans. Both isolates carried the complete SCCmec XI element. They lacked the lukF-PV/lukS-PV and lukM/lukF-P83 genes, but harboured a gene for an exfoliative toxin homologue previously described from Staphylococcus hyicus, Staphylococcus pseudintermedius and other S. aureus of the CC130 lineage. To the best of our knowledge, these are the first reported cases of CC130-MRSA-XI in hedgehogs. Given that one of the samples was taken as early as 2003, this was the earliest detection of this strain and of mecC in Sweden. This and several other recent observations suggest that CC130 might be a zoonotic lineage of S. aureus and that SCCmec XI/mecC may have originated from animal pathogens.

Evaluation of an Immunochromatographic Assay for Rapid Detection of Penicillin-Binding Protein 2a in Human and Animal Staphylococcus intermedius Group, Staphylococcus lugdunensis, and Staphylococcus schleiferi Clinical Isolates.

PubMed

Arnold, A R; Burnham, C-A D; Ford, B A; Lawhon, S D; McAllister, S K; Lonsway, D; Albrecht, V; Jerris, R C; Rasheed, J K; Limbago, B; Burd, E M; Westblade, L F

2016-03-01

The performance of a rapid penicillin-binding protein 2a (PBP2a) detection assay, the Alere PBP2a culture colony test, was evaluated for identification of PBP2a-mediated beta-lactam resistance in human and animal clinical isolates of Staphylococcus intermedius group, Staphylococcus lugdunensis, and Staphylococcus schleiferi. The assay was sensitive and specific, with all PBP2a-negative and PBP2a-positive strains testing negative and positive, respectively. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Biological Activities and Secondary Metabolite Screening of Rumex hastatus Extract through Fourier Transform Infrared and Raman Spectroscopy.

PubMed

Andleeb, Saiqa; Naseer, Anum; Ali, Shaukat; Mustafa, Rozina Ghulam; Zafar, Atiya; Shafique, Irsa; Ihsan-Ul-Haq; Ismail, Muhammad; Saleem, Muhammad; Mansoor, Qaiser

2018-01-01

Human infectious diseases are caused by various pathogens including bacteria, fungi, viruses, parasites, and protozoans. These infectious agents are controlled by using synthetic drugs as well as natural sources. The aim of current study was to evaluate the antibacterial effect of Rumex hastatus against clinical bacterial pathogens. In current research antibacterial effect of Rumex hastatus was analyzed against seven clinical pathogenic bacteria such as Escherichia coli, Serratia marcescens, Streptococcus pyogenes, Staphylococcus epidermidis, Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa through agar well diffusion method. The boiled extract was used for the phytochemical screening, antioxidant potential, thin layer chromatography, bio-autography, and spot screening. Genomic DNA was extracted to find the DNA protection effect of R. hastatus. Antibacterial results showed that diethyl ether extract has the maximum inhibition of S. pyogenes (9.66 ± 0.57 mm). Acetone and diethyl ether extracts showed moderate inhibition of K. pneumoniae (6.33 ± 1.52 mm and 5.66 ±1.15 mm) and S. aureus (6.33 ± 1.52 mm and 5.66 ± 0.57 mm). Similarly, chloroform extract indicated moderate inhibition of S. pyogenes (5.66 ± 1.15 mm). Ethanol extract had low or even no effect on the growth of bacteria. Genomic DNA extraction also encouraged the antibacterial effect of R. hastatus. Various phytochemical constituents such as ketoses, oligosaccharides, amino acids, amines, sugars, flavonoids, and antioxidant constituents were detected. TLC-Bioautography and spot screening results revealed the potential use of R. hustatus as an antibacterial agent. It was concluded that most of the tested fractions appeared as an important source for the discovery of new antimicrobial drugs. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Vaccine potential of poly-1-6 beta-D-N-succinylglucosamine, an immunoprotective surface polysaccharide of Staphylococcus aureus and Staphylococcus epidermidis.

PubMed

Mckenney, D; Pouliot, K; Wang, Y; Murthy, V; Ulrich, M; Döring, G; Lee, J C; Goldmann, D A; Pier, G B

2000-09-29

Staphylococcus aureus and S. epidermidis are among the most common causes of nosocomial infection, and S. aureus is also of major concern to human health due to its occurrence in community-acquired infections. These staphylococcal species are also major pathogens for domesticated animals. We have previously identified poly-N-succinyl beta-1-6 glucosamine (PNSG) as the chemical form of the S. epidermidis capsular polysaccharide/adhesin (PS/A) which mediates adherence of coagulase-negative staphylococci (CoNS) to biomaterials, serves as the capsule for strains of CoNS that express PS/A, and is a target for protective antibodies. We have recently found that PNSG is made by S. aureus as well, where it is an environmentally regulated, in vivo-expressed surface polysaccharide and similarly serves as a target for protective immunity. Only a minority of fresh human clinical isolates of S. aureus elaborate PNSG in vitro but most could be induced to do so under specific in vitro growth conditions. However, by immunofluorescence microscopy, S. aureus cells in infected human sputa and lung elaborated PNSG. The ica genes, previously shown to encode proteins in CoNS that synthesize PNSG, were found by PCR in all S. aureus strains examined, and immunogenic and protective PNSG could be isolated from S. aureus. Active and passive immunization of mice with PNSG protected them against metastatic kidney infections after intravenous inoculation with eight phenotypically PNSG-negative S. aureus. Isolates recovered from kidneys expressed PNSG, but expression was lost with in vitro culture. Strong antibody responses to PNSG were elicited in S. aureus infected mice, and a PNSG-capsule was observed by electron microscopy on isolates directly plated from infected kidneys. PNSG represents a previously unidentified surface polysaccharide of S. aureus that is elaborated during human and animal infection and is a prominent target for protective antibodies.

Rapid Screening of Natural Plant Extracts with Calcium Diacetate for Differential Effects Against Foodborne Pathogens and a Probiotic Bacterium.

PubMed

Colonna, William; Brehm-Stecher, Byron; Shetty, Kalidas; Pometto, Anthony

2017-12-01

This study focused on advancing a rapid turbidimetric bioassay to screen antimicrobials using specific cocktails of targeted foodborne bacterial pathogens. Specifically, to show the relevance of this rapid screening tool, the antimicrobial potential of generally recognized as safe calcium diacetate (DAX) and blends with cranberry (NC) and oregano (OX) natural extracts was evaluated. Furthermore, the same extracts were evaluated against beneficial lactic acid bacteria. The targeted foodborne pathogens evaluated were Escherichia coli O157:H7, Salmonella spp., Listeria monocytogenes, and Staphylococcus aureus using optimized initial cocktails (∼10 8 colony-forming unit/mL) containing strains isolated from human food outbreaks. Of all extracts evaluated, 0.51% (w/v) DAX in ethanol was the most effective against all four pathogens. However, DAX when reduced to 0.26% and with added blends from ethanol extractions consisting of DAX:OX (3:1), slightly outperformed or was equal to same levels of DAX alone. Subculture of wells in which no growth occurred after 1 week indicated that all water and ethanol extracts were bacteriostatic against the pathogens tested. All the targeted antimicrobials had no effect on the probiotic organism Lactobacillus plantarum. The use of such rapid screening methods combined with the use of multistrain cocktails of targeted foodborne pathogens from outbreaks will allow rapid large-scale screening of antimicrobials and enable further detailed studies in targeted model food systems.

Cyclic dipeptides from rhabditid entomopathogenic nematode-associated Bacillus cereus have antimicrobial activities.

PubMed

Nishanth Kumar, S; Nath, Vishnu Sukumari; Pratap Chandran, R; Nambisan, Bala

2014-02-01

The cell free culture filtrate of Bacillus cereus associated with an entomopathogenic nematode, Rhabditis (Oscheius) sp. exhibited strong antimicrobial activity. The ethyl acetate extract of the bacterial culture filtrate was purified by silica gel column chromatography to obtain four bioactive compounds. The structure and absolute stereochemistry of these compounds were determined based on extensive spectroscopic analyses (FABMS, (1)H NMR, (13)C NMR, (1)H-(1)H COSY, (1)H-(13)C HMBC) and Marfey's method. The compounds were identified as cyclic dipeptides (CDPs): cyclo(L-Pro-L-Trp), cyclo(L-Leu-L-Val), cyclo(D-Pro-D-Met), and cyclo(D-Pro-D-Phe), respectively. Compounds recorded significant antibacterial activity against all the test bacteria (Staphylococcus epidermidis, Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa and methicillin-resistant S. aureus) except cyclo(L-Leu-L-Val). Cyclo(L-Leu-L-Val) recorded activity only against Gram positive bacteria. Best antibacterial activity was recorded by cyclo(L-Pro-L-Trp) against S. aureus (4 μg/ml). The four compounds were active against all the five fungi tested (Trichophyton rubrum, Aspergillus flavus, Candida albicans, Candida tropicalis and Cryptococcus neoformans) and the activity was compared with amphotericin B, the standard fungicide. The highest activity of 1 μg/ml by cyclo(L-Pro-L-Trp) was recorded against T. rubrum, a human pathogen responsible for causing athlete's foot, jock itch, and ringworm. The activity of cyclo(L-Pro-L-Trp) against T. rubrum, C. neoformans and C. albicans were better than amphotericin B, the standard antifungal agent. To our knowledge, this is the first report of antifungal activity of CDPs against the human pathogenic fungi T. rubrum and C. neoformans. The four CDPs are nontoxic to healthy human cell line up to 200 μg/ml. We conclude that the bacterium associated with entomopathogenic nematode is promising sources of natural antimicrobial secondary metabolites, which may receive greater benefit as potential sources of new drugs in the pharmaceutical industry.

The clinical impact of livestock-associated methicillin-resistant Staphylococcus aureus of the clonal complex 398 for humans.

PubMed

Becker, Karsten; Ballhausen, Britta; Kahl, Barbara C; Köck, Robin

2017-02-01

In the past decade, livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) strains in particular of the clonal complex (CC) 398 have emerged in many parts of the world especially in areas with a high density of pig farming. In those regions, farmworkers and other individuals with professional contact to livestock are very frequently colonized with LA-MRSA. These persons are the presumably source for LA-MRSA transmission to household members and other parts of the human population. Altogether, colonization and/or infection of these individuals lead to the introduction of LA-MRSA into hospitals and other healthcare facilities. Since LA-MRSA CC398 have been found to be specifically adapted to their animal hosts in terms of the equipment with virulence factors, their pathogenicity to human patients is a matter of debate with first reports about clinical cases. Meanwhile, case reports, case series and few studies have demonstrated the capability of LA-MRSA to cause all types of infections attributed to S. aureus in general including fatal courses. Human infections observed comprise e.g. bacteremia, pneumonia, osteomyelitis, endocarditis and many manifestations of skin and soft tissue infections. However, inpatients affected by MRSA CC398 generally show different demographic (e.g. younger, shorter length of hospital stay) and clinical characteristics (e.g. less severe complications) which may explain or at least contribute to a lower disease burden of LA-MRSA compared to other MRSA clonal lineages. Copyright © 2015 Elsevier B.V. All rights reserved.

Preclinical Investigations Reveal the Broad-Spectrum Neutralizing Activity of Peptide Pep19-2.5 on Bacterial Pathogenicity Factors

PubMed Central

Sánchez-Gómez, Susana; Martinez de Tejada, Guillermo; Dömming, Sabine; Brandenburg, Julius; Kaconis, Yani; Hornef, Mathias; Dupont, Aline; Marwitz, Sebastian; Goldmann, Torsten; Ernst, Martin; Gutsmann, Thomas; Schürholz, Tobias

2013-01-01

Bacterial infections are known to cause severe health-threatening conditions, including sepsis. All attempts to get this disease under control failed in the past, and especially in times of increasing antibiotic resistance, this leads to one of the most urgent medical challenges of our times. We designed a peptide to bind with high affinity to endotoxins, one of the most potent pathogenicity factors involved in triggering sepsis. The peptide Pep19-2.5 reveals high endotoxin neutralization efficiency in vitro, and here, we demonstrate its antiseptic/anti-inflammatory effects in vivo in the mouse models of endotoxemia, bacteremia, and cecal ligation and puncture, as well as in an ex vivo model of human tissue. Furthermore, we show that Pep19-2.5 can bind and neutralize not only endotoxins but also other bacterial pathogenicity factors, such as those from the Gram-positive bacterium Staphylococcus aureus. This broad neutralization efficiency and the additive action of the peptide with common antibiotics makes it an exceptionally appropriate drug candidate against bacterial sepsis and also offers multiple other medication opportunities. PMID:23318793

Visible-Light-Induced Bactericidal Activity of a Nitrogen-Doped Titanium Photocatalyst against Human Pathogens

PubMed Central

Wong, Ming-Show; Chu, Wen-Chen; Sun, Der-Shan; Huang, Hsuan-Shun; Chen, Jiann-Hwa; Tsai, Pei-Jane; Lin, Nien-Tsung; Yu, Mei-Shiuan; Hsu, Shang-Feng; Wang, Shih-Lien; Chang, Hsin-Hou

2006-01-01

The antibacterial activity of photocatalytic titanium dioxide (TiO2) substrates is induced primarily by UV light irradiation. Recently, nitrogen- and carbon-doped TiO2 substrates were shown to exhibit photocatalytic activities under visible-light illumination. Their antibacterial activity, however, remains to be quantified. In this study, we demonstrated that nitrogen-doped TiO2 substrates have superior visible-light-induced bactericidal activity against Escherichia coli compared to pure TiO2 and carbon-doped TiO2 substrates. We also found that protein- and light-absorbing contaminants partially reduce the bactericidal activity of nitrogen-doped TiO2 substrates due to their light-shielding effects. In the pathogen-killing experiment, a significantly higher proportion of all tested pathogens, including Shigella flexneri, Listeria monocytogenes, Vibrio parahaemolyticus, Staphylococcus aureus, Streptococcus pyogenes, and Acinetobacter baumannii, were killed by visible-light-illuminated nitrogen-doped TiO2 substrates than by pure TiO2 substrates. These findings suggest that nitrogen-doped TiO2 has potential application in the development of alternative disinfectants for environmental and medical usages. PMID:16957236

High diversity of Staphylococcus aureus and Staphylococcus pseudintermedius lineages and toxigenic traits in healthy pet-owning household members. Underestimating normal household contact?

PubMed

Gómez-Sanz, Elena; Torres, Carmen; Lozano, Carmen; Zarazaga, Myriam

2013-01-01

Forty-three unrelated pet-owning households were screened in Spain to study the Staphylococcus aureus and Staphylococcus pseudintermedius nasal carriage, their genetic lineages and virulence traits. Sixty-seven healthy owners and 66 healthy pets were investigated. Isolates characterization was performed and potential interspecies transmission was assessed. S. aureus was present in 51.2% of households studied while S. pseudintermedius in 30.2%. Twenty-eight owners (41.8%) carried S. aureus: one methicillin-resistant S. aureus (MRSA) [t5173-ST8-SCCmecIVa] and 27 methicillin-susceptible S. aureus (MSSA). Three owners (4.5%) were colonized by methicillin-susceptible S. pseudintermedius (MSSP). Fifteen pets (22.7%) carried S. pseudintermedius: two methicillin-resistant S. pseudintermedius (MRSP) [ST71-SCCmecII/III; ST92-SCCmecV] and 13 MSSP; in addition, 8 pets (12.1%) presented MSSA. High diversity of spa and sequence types (STs) was detected. Typical livestock-associated S. aureus lineages (CC398, CC9) were observed in humans and/or companion animals and hospital and/or community-acquired S. aureus lineages (CC45, CC121, CC5, CC8) were detected among pets. Almost 40% of S. pseudintermedius were multidrug-resistant. S. aureus isolates harboured a remarkable high number of virulence genes. The expA gene was detected in 3 S. pseudintermedius isolates. Identical strains from both owners and their pets were identified in 5 households (11.6%): (a) four MSSA (t073-ST45/CC45, t159-ST121/CC121, t209-ST109/CC9, t021-ST1654([new])/singleton) and (b) one multidrug-resistant MSSP (ST142([new])). Highly clonally diverse and toxigenic S. aureus and S. pseudintermedius are common colonizers of healthy humans and pets. The presence of these bacterial species, virulence genes, and interspecies transmission detected, points out to consider pet ownership as a risk factor to acquire, maintain and spread, potential pathogenic bacteria. Copyright © 2012 Elsevier Ltd. All rights reserved.

Antimicrobial role of human meibomian lipids at the ocular surface.

PubMed

Mudgil, Poonam

2014-10-14

Human meibomian lipids form the outermost lipid layer of the tear film and serve many important functions to maintain its integrity. Although not investigated earlier, these lipids may have antimicrobial properties that help in strengthening the innate host defense of tears at the ocular surface. The aim of this study was to investigate the antimicrobial role of human meibomian lipids. Ocular pathogenic bacteria, Staphylococcus aureus 31, Pseudomonas aeruginosa 19, Pseudomonas aeruginosa 20, and Serratia marcescens 35, were grown in the presence and absence of human meibomian lipids in an artificial tear solution at the physiological temperature. Viable counts were obtained to note the number of bacteria surviving the treatment with meibomian lipids. Bacterial cells were imaged using scanning electron microscopy to observe the damages caused by meibomian lipids. Viable count results showed that in the presence of meibomian lipids, growth of all bacteria was considerably lower. Scanning electron microscopy showed that meibomian lipids caused extensive cellular damage to bacteria as manifested in smaller size, loss of aggregation, abnormal phenotype, cellular distortion, damaged cell wall, and cell lysis. This is the first-ever report of the antimicrobial role of human meibomian lipids. These lipids possess antimicrobial properties against both Gram-positive and Gram-negative bacteria and are involved in the innate host defense of tears in protecting the ocular surface against microbial pathogens. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

Methicillin-resistant Staphylococcus aureus as a cause of neonatal suppurative parotitis: a report of two cases and review of the literature.

PubMed

Donovan, Sean T; Rohman, Grant T; Selph, John P; Rajan, Roy; Stocks, Rosemary M; Thompson, Jerome W

2013-06-01

Suppurative parotitis is an uncommon entity identified in newborns. While Staphylococcus aureus has been frequently identified as the causative pathogen among the few patients diagnosed with neonatal suppurative parotitis (NSP), there has only been one prior case described in the literature that was due to methicillin-resistant Staphylococcus aureus (MRSA). Because of its virulence, MRSA presents new and substantial challenges for the surgeon; we describe two cases of NSP caused by MRSA and the subsequent surgical intervention necessitated for cure. We also include a review of all cases of NSP described in the English-language literature.

Animal production food safety: priority pathogens for standard setting by the World Organisation for Animal Health.

PubMed

Knight-Jones, T J D; Mylrea, G E; Kahn, S

2010-12-01

In this short study, expert opinion and a literature review were used to identify the pathogens that should be prioritised by the World Organisation for Animal Health (OIE) for the development of future standards for animal production food safety. Prioritisation was based on a pathogen's impact on human health and amenability to control using on-farm measures. As the OIE mandate includes alleviation of global poverty, the study focused on developing countries and those with 'in-transition' economies. The regions considered were Eastern Europe, Asia, the Middle East, Africa and South America. Salmonella (from species other than poultry) and pathogenic Escherichia coli were considered to be top priorities. Brucella spp., Echinococcus granulosus and Staphylococcus aureus were also mentioned by experts. As Salmonella, and to a lesser extent pathogenic E. coli, can be controlled by on-farm measures, these pathogens should be considered for prioritisation in future standard setting. On-farm control measures for Brucella spp. will be addressed in 2010-2011 in a review of the OLE Terrestrial Animal/Health Code chapter on brucellosis. In Africa, E. granulosus, the causative agent of hydatidosis, was estimated to have the greatest impact of all pathogens that could potentially be transmitted by food (i.e. via contamination). It was also listed for the Middle East and thought to be of importance by both South American experts consulted. Taenia saginata was thought to be of importance in South America and Africa and by one expert in the Middle East.

Identification of two proline transport systems in Staphylococcus aureus and their possible roles in osmoregulation.

PubMed

Bae, J H; Miller, K J

1992-02-01

The food-borne pathogen Staphylococcus aureus is distinguished from other food-borne pathogens by its ability to grow at water activity values below 0.90. Previous studies have indicated that proline accumulation mediated by transport represents a primary osmoregulatory strategy utilized by this bacterium (C. B. Anderson and L. D. Witter, Appl. Environ, Microbiol. 43:1501-1503, 1982; I. Koujima, H. Hayashi, K. Tomochika, A. Okabe, and Y. Kanemasa, Appl. Environ. Microbiol. 35:467-470, 1978; K. J. Miller, S. C. Zelt, and J.-H. Bae, Curr. Microbiol. 23:131-137, 1991). In this study, we demonstrate the presence of two proline transport systems within whole cells of S. aureus, a high-affinity transport system (Km, 7 microM) and a low-affinity transport system (Km, 420 microM). Our results indicate that the low-affinity proline transport system is osmotically activated and is the primary system responsible for the accumulation of proline by this pathogen during growth at low water activity.

Potential Role for Telavancin in Bacteremic Infections Due to Gram-Positive Pathogens: Focus on Staphylococcus aureus

PubMed Central

Corey, G. Ralph; Rubinstein, Ethan; Stryjewski, Martin E.; Bassetti, Matteo; Barriere, Steven L.

2015-01-01

Staphylococcus aureus bacteremia (SAB) is one of the most common serious bacterial infections and the most frequent invasive infection due to methicillin-resistant S. aureus (MRSA). Treatment is challenging, particularly for MRSA, because of limited treatment options. Telavancin is a bactericidal lipoglycopeptide antibiotic that is active against a range of clinically relevant gram-positive pathogens including MRSA. In experimental animal models of sepsis telavancin was shown to be more effective than vancomycin. In clinically evaluable patients enrolled in a pilot study of uncomplicated SAB, cure rates were 88% for telavancin and 89% for standard therapy. Among patients with infection due to only gram-positive pathogens enrolled in the 2 phase 3 studies of telavancin for treatment of hospital-acquired pneumonia, cure rates for those with bacteremic S. aureus pneumonia were 41% (9/22, telavancin) and 40% (10/25, vancomycin) with identical mortality rates. These data support further evaluation of telavancin in larger, prospective studies of SAB. PMID:25472944

Intracellular survival of Staphylococcus aureus during persistent infection in the insect Tenebrio molitor.

PubMed

McGonigle, John E; Purves, Joanne; Rolff, Jens

2016-06-01

Survival of bacteria within host cells and tissues presents a challenge to the immune systems of higher organisms. Escape from phagocytic immune cells compounds this issue, as immune cells become potential vehicles for pathogen dissemination. However, the duration of persistence within phagocytes and its contribution to pathogen load has yet to be determined. We investigate the immunological significance of intracellular persistence within the insect model Tenebrio molitor, assessing the extent, duration and location of bacterial recovery during a persistent infection. Relative abundance of Staphylococcus aureus in both intracellular and extracellular fractions was determined over 21 days, and live S. aureus were successfully recovered from both the hemolymph and within phagocytic immune cells across the entire time course. The proportion of bacteria recovered from within phagocytes also increased over time. Our results show that to accurately estimate pathogen load it is vital to account for bacteria persisting within immune cells. Copyright © 2016 Elsevier Ltd. All rights reserved.

Antibacterial and cytotoxic activities of the sesquiterpene lactones cnicin and onopordopicrin.

PubMed

Bach, Sandra M; Fortuna, Mario A; Attarian, Rodgoun; de Trimarco, Juliana T; Catalán, César A N; Av-Gay, Yossef; Bach, Horacio

2011-02-01

The antimicrobial and cytotoxic activities of chloroform extracts from the weeds Centaurea tweediei and C. diffusa, and the main sesquiterpene lactones isolated from these species, onopordopicrin and cnicin, respectively, were assayed. Results show that the chloroform extracts from both Centaurea species possess antibacterial activities against a panel of Gram-positive and Gram-negative bacteria. Remarkable antibacterial activity against methicillin-resistant Staphylococcus aureus was also measured. Both the extracts and the purified sesquiterpene lactones show high cytotoxicity against human-derived macrophages. Despite this cytotoxicity, C. diffusa chloroform extract and cnicin are attractive candidates for evaluation as antibiotics in topical preparations against skin-associated pathogens.

The Systemic and Pulmonary Immune Response to Staphylococcal Enterotoxins

PubMed Central

Kumar, Sanjeev; Ménoret, Antoine; Ngoi, Soo-Mun; Vella, Anthony T.

2010-01-01

In response to environmental cues the human pathogen Staphylococcus aureus synthesizes and releases proteinaceous enterotoxins. These enterotoxins are natural etiologic entities of severe food poisoning, toxic shock syndrome, and acute diseases. Staphylococcal enterotoxins are currently listed as Category B Bioterrorism Agents by the Center for Disease Control and Prevention. They are associated with respiratory illnesses, and may contribute to exacerbation of pulmonary disease. This likely stems from the ability of Staphylococcal enterotoxins to elicit powerful episodes of T cell stimulation resulting in release of pro-inflammatory cytokines. Here, we discuss the role of the immune system and potential mechanisms of disease initiation and progression. PMID:22069664

Antimicrobial Activity of Pantothenol against Staphylococci Possessing a Prokaryotic Type II Pantothenate Kinase

PubMed Central

Chohnan, Shigeru; Murase, Misa; Kurikawa, Kota; Higashi, Kodai; Ogata, Yuta

2014-01-01

Pantothenol is a provitamin of pantothenic acid (vitamin B5) that is widely used in healthcare and cosmetic products. This analog of pantothenate has been shown to markedly inhibit the phosphorylation activity of the prokaryotic type II pantothenate kinase of Staphylococcus aureus, which catalyzes the first step of the coenzyme A biosynthetic pathway. Since type II enzymes are found exclusively in staphylococci, pantothenol suppresses the growth of S. aureus, S. epidermidis, and S. saprophyticus, which inhabit the skin of humans. Therefore, the addition of this provitamin to ointment and skincare products may be highly effective in preventing infections by opportunistic pathogens. PMID:24759689

A New Class of Quorum Quenching Molecules from Staphylococcus Species Affects Communication and Growth of Gram-Negative Bacteria

PubMed Central

Chu, Ya-Yun; Nega, Mulugeta; Wölfle, Martina; Plener, Laure; Grond, Stephanie; Jung, Kirsten; Götz, Friedrich

2013-01-01

The knowledge that many pathogens rely on cell-to-cell communication mechanisms known as quorum sensing, opens a new disease control strategy: quorum quenching. Here we report on one of the rare examples where Gram-positive bacteria, the ‘Staphylococcus intermedius group’ of zoonotic pathogens, excrete two compounds in millimolar concentrations that suppress the quorum sensing signaling and inhibit the growth of a broad spectrum of Gram-negative beta- and gamma-proteobacteria. These compounds were isolated from Staphylococcus delphini. They represent a new class of quorum quenchers with the chemical formula N-[2-(1H-indol-3-yl)ethyl]-urea and N-(2-phenethyl)-urea, which we named yayurea A and B, respectively. In vitro studies with the N-acyl homoserine lactone (AHL) responding receptor LuxN of V. harveyi indicated that both compounds caused opposite effects on phosphorylation to those caused by AHL. This explains the quorum quenching activity. Staphylococcal strains producing yayurea A and B clearly benefit from an increased competitiveness in a mixed community. PMID:24098134

Exploration of Fungal Association From Hard Coral Against Pathogen MDR Staphylococcus haemolyticus

NASA Astrophysics Data System (ADS)

Cristianawati, O.; Radjasa, O. K.; Sabdono, A.; Trianto, A.; Sabdaningsih, A.; Sibero, M. T.; Nuryadi, H.

2017-02-01

Staphylococcus haemolyticus are opportunistic bacteria and as the second leading cause of nosocomial infections. It is a disease causing septicemia, peritonitis, otitis, and urinary tract infections and infections of the eye. It also a phenotype resistant to multiple antibiotics commercial. There is now an urgency to find an alternative antibiotics to combat this bacteria. It has been widely reported that many bioactive marine natural products from marine invertebrate have striking similarities to metabolites of their associated microorganisms including fungi. Hard coral associated microorganisms are among of the most interesting and promising marine natural product sources, which produce with various biological activities. The proposed work focused on the discovery of bioactive compounds and also estimated the phylogenetic diversity from fungal association of hard coral against pathogen MDR Staphylococcus haemolyticus. A total of 32 fungal association, FHP 7 which were isolated from Favia sp. capable of inhibiting the growth MDR. Molecular identification based on 18S rRNA gene sequences revealed that the active fungal association belonged 100% to the members from one of the genera Trichoderma longibrachiatum. Accession Number LC185084.1.

NORMAL FLORA OF THE NOSE, THROAT, AND LOWER INTESTINE OF DOGS

PubMed Central

Clapper, W. E.; Meade, G. H.

1963-01-01

Clapper, W. E. (The Lovelace Foundation for Medical Education and Research, Albuquerque, N.M.) and G. H. Meade. Normal flora of the nose, throat, and lower intestine of dogs. J. Bacteriol. 85:643–648. 1963.—An attempt was made to isolate and identify the complete normal flora of the rectum, nose, and throat of beagles. For primary isolation, 12 different kinds of media were used. Incubation of blood agar plates and slants anaerobically, and of thioglycolate broth aerobically, allowed the growth of obligate anaerobes. From the rectal specimens, 20 species of bacteria and 10 species of fungi were isolated and identified. The organisms were similar to those found in the human intestine. Escherichia coli, Streptococcus mitis, enterococci, S. lactis, Bacillus species, and coliforms other than E. coli were most frequently encountered. The frequency of occurrence was approximately the same at both samplings in more commonly cultured bacteria. Pathogenic E. coli were isolated from nearly one-third of the first specimens. These were the only human pathogens observed. In the throat cultures, 29 species of bacteria and 2 species of yeasts were identified, and 27 species of bacteria were identified from the nasal cultures. S. mitis, Neisseria, and coagulase-negative Staphylococcus were most often isolated. The flora was similar to that found in human nose and throat cultures, except that more Haemophilus and pneumococcus and fewer coliforms are generally found in human throats. Organisms resembling human pathogens were group A streptococci and coagulase-positive staphylococci. These were isolated infrequently. It appears that this kind of examination would reveal any significant changes in normal flora that might be related to the health of the animal. PMID:14042944

Manuka honey inhibits adhesion and invasion of medically important wound bacteria in vitro.

PubMed

Maddocks, Sarah Elizabeth; Jenkins, Rowena Eleri; Rowlands, Richard Samuel; Purdy, Kevin John; Cooper, Rose Agnes

2013-12-01

To characterize the effect of manuka honey on medically important wound bacteria in vitro, focusing on its antiadhesive properties. Crystal violet biofilm assays, fluorescent microscopy, protein adhesion assay and gentamicin protection assay were used to determine the impact of manuka honey on biofilm formation, human protein binding and adherence to/invasion into human keratinocytes. Manuka honey effectively disrupted and caused extensive cell death in biofilms of Staphylococcus aureus, Pseudomonas aeruginosa and Streptococcus pyogenes. Sublethal doses of manuka honey inhibited bacterial adhesion to the fibronectin, fibrinogen and collagen. Manuka honey impaired adhesion of laboratory and clinical isolates of S. aureus, P. aeruginosa and S. pyogenes to human keratinocytes in vitro, and inhibited invasion by S. pyogenes and homogeneous vancomycin intermediate S. aureus. Manuka honey can directly affect bacterial cells embedded in a biofilm and exhibits antiadhesive properties against three common wound pathogens.

High incidence of oxacillin-susceptible mecA-positive Staphylococcus aureus (OS-MRSA) associated with bovine mastitis in China.

PubMed

Pu, WanXia; Su, Yang; Li, JianXi; Li, ChunHui; Yang, ZhiQiang; Deng, HaiPing; Ni, ChunXia

2014-01-01

Staphylococcus aureus is a main cause of bovine mastitis and a major pathogen affecting human health. The emergence and spread of methicillin-resistant Staphylococcus aureus (MRSA) has become a significant concern for both animal health and public health. This study investigated the incidence of MRSA in milk samples collected from dairy cows with clinical mastitis and characterized the MRSA isolates using antimicrobial susceptibility tests and genetic typing methods. In total, 103 S. aureus isolates were obtained from dairy farms in 4 different provinces in China, including Gansu, Shanghai, Sichuan, and Guizhou. Antimicrobial susceptibility testing of these isolates revealed that the resistance rates to penicillin and sulfamethoxazole were high, while the resistance rates to ciprofloxacin and vancomycin were low. Among the 103 isolates, 49 (47.6%) were found to be mecA-positive, indicating the high incidence of MRSA. However, 37 of the 49 mecA-positive isolates were susceptible to oxacillin as determined by antimicrobial susceptibility assays and were thus classified as oxacillin-susceptible mecA-positive S. aureus (OS-MRSA). These isolates could be misclassified as methicillin susceptible Staphylococcus aureus (MSSA) if genetic detection of mecA was not performed. Molecular characterization of selected mecA-positive isolates showed that they were all negative with Panton-Valentine leukocidin (PVL), but belonged to different spa types and SCCmec types. These results indicate that OS-MRSA is common in bovine mastitis in China and underscore the need for genetic methods (in addition to phenotypic tests) to accurately identify MRSA.

The impact of CodY on virulence determinant production in community-associated methicillin-resistant Staphylococcus aureus.

PubMed

Rivera, Frances E; Miller, Halie K; Kolar, Stacey L; Stevens, Stanley M; Shaw, Lindsey N

2012-01-01

Staphylococcus aureus is a leading human pathogen of both hospital and community-associated diseases worldwide. This organism causes a wealth of infections within the human host as a result of the vast arsenal of toxins encoded within its genome. Previous transcriptomic studies have shown that toxin production in S. aureus can be strongly impacted by the negative regulator CodY. CodY acts by directly, and indirectly (via Agr), repressing toxin production during times of plentiful nutrition. In this study, we use iTRAQ-based proteomics for the first time to study virulence determinant production in S. aureus, so as to correlate transcriptional observations with actual changes in protein synthesis. Using a codY mutant in the epidemic CA-MRSA clone USA300 we demonstrate that deletion of this transcription factor results in a major upregulation of toxin synthesis in both post-exponential and stationary growth. Specifically, we observe hyper-production of secreted proteases, leukocidins and hemolysins in both growth phases in the USA300 codY mutant. Our findings demonstrate the power of mass spectrometry-based quantitative proteomics for studying toxin production in S. aureus, and the importance of CodY to this central process in disease causation and infection. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Transmission Dynamics of Methicillin-Resistant Staphylococcus aureus in Pigs

PubMed Central

Crombé, Florence; Argudín, M. Angeles; Vanderhaeghen, Wannes; Hermans, Katleen; Haesebrouck, Freddy; Butaye, Patrick

2013-01-01

From the mid-2000s on, numerous studies have shown that methicillin-resistant Staphylococcus aureus (MRSA), renowned as human pathogen, has a reservoir in pigs and other livestock. In Europe and North America, clonal complex (CC) 398 appears to be the predominant lineage involved. Especially worrisome is its capacity to contaminate humans in close contact with affected animals. Indeed, the typical multi-resistant phenotype of MRSA CC398 and its observed ability of easily acquiring genetic material suggests that MRSA CC398 strains with an increased virulence potential may emerge, for which few therapeutic options would remain. This questions the need to implement interventions to control the presence and spread of MRSA CC398 among pigs. MRSA CC398 shows a high but not fully understood transmission potential in the pig population and is able to persist within that population. Although direct contact is probably the main route for MRSA transmission between pigs, also environmental contamination, the presence of other livestock, the herd size, and farm management are factors that may be involved in the dissemination of MRSA CC398. The current review aims at summarizing the research that has so far been done on the transmission dynamics and risk factors for introduction and persistence of MRSA CC398 in farms. PMID:23518663

A peptide factor secreted by Staphylococcus pseudintermedius exhibits properties of both bacteriocins and virulence factors.

PubMed

Wladyka, Benedykt; Piejko, Marcin; Bzowska, Monika; Pieta, Piotr; Krzysik, Monika; Mazurek, Łukasz; Guevara-Lora, Ibeth; Bukowski, Michał; Sabat, Artur J; Friedrich, Alexander W; Bonar, Emilia; Międzobrodzki, Jacek; Dubin, Adam; Mak, Paweł

2015-09-28

Staphylococcus pseudintermedius is a common commensal bacterium colonizing the skin and mucosal surfaces of household animals. However, it has recently emerged as a dangerous opportunistic pathogen, comparable to S. aureus for humans. The epidemiological situation is further complicated by the increasing number of methicillin-resistant S. pseudintermedius infections and evidence of gene transmission driving antibiotic resistance between staphylococci colonizing human and zoonotic hosts. In the present study, we describe a unique peptide, BacSp222, that possesses features characteristic of both bacteriocins and virulence factors. BacSp222 is secreted in high quantities by S. pseudintermedius strain 222 isolated from dog skin lesions. This linear, fifty-amino-acid highly cationic peptide is plasmid-encoded and does not exhibit significant sequence similarities to any other known peptides or proteins. BacSp222 kills gram-positive bacteria (at doses ranging from 0.1 to several micromol/l) but also demonstrates significant cytotoxic activities towards eukaryotic cells at slightly higher concentrations. Moreover, at nanomolar concentrations, the peptide also possesses modulatory properties, efficiently enhancing interferon gamma-induced nitric oxide release in murine macrophage-like cell lines. BacSp222 appears to be one of the first examples of multifunctional peptides that breaks the convention of splitting bacteriocins and virulence factors into two unrelated groups.

A peptide factor secreted by Staphylococcus pseudintermedius exhibits properties of both bacteriocins and virulence factors

PubMed Central

Wladyka, Benedykt; Piejko, Marcin; Bzowska, Monika; Pieta, Piotr; Krzysik, Monika; Mazurek, Łukasz; Guevara-Lora, Ibeth; Bukowski, Michał; Sabat, Artur J.; Friedrich, Alexander W.; Bonar, Emilia; Międzobrodzki, Jacek; Dubin, Adam; Mak, Paweł

2015-01-01

Staphylococcus pseudintermedius is a common commensal bacterium colonizing the skin and mucosal surfaces of household animals. However, it has recently emerged as a dangerous opportunistic pathogen, comparable to S. aureus for humans. The epidemiological situation is further complicated by the increasing number of methicillin-resistant S. pseudintermedius infections and evidence of gene transmission driving antibiotic resistance between staphylococci colonizing human and zoonotic hosts. In the present study, we describe a unique peptide, BacSp222, that possesses features characteristic of both bacteriocins and virulence factors. BacSp222 is secreted in high quantities by S. pseudintermedius strain 222 isolated from dog skin lesions. This linear, fifty-amino-acid highly cationic peptide is plasmid-encoded and does not exhibit significant sequence similarities to any other known peptides or proteins. BacSp222 kills gram-positive bacteria (at doses ranging from 0.1 to several micromol/l) but also demonstrates significant cytotoxic activities towards eukaryotic cells at slightly higher concentrations. Moreover, at nanomolar concentrations, the peptide also possesses modulatory properties, efficiently enhancing interferon gamma-induced nitric oxide release in murine macrophage-like cell lines. BacSp222 appears to be one of the first examples of multifunctional peptides that breaks the convention of splitting bacteriocins and virulence factors into two unrelated groups. PMID:26411997

Neutrophil-generated oxidative stress and protein damage in Staphylococcus aureus

PubMed Central

Beavers, William N.; Skaar, Eric P.

2016-01-01

Staphylococcus aureus is a ubiquitous, versatile and dangerous pathogen. It colonizes over 30% of the human population, and is one of the leading causes of death by an infectious agent. During S. aureus colonization and invasion, leukocytes are recruited to the site of infection. To combat S. aureus, leukocytes generate an arsenal of reactive species including superoxide, hydrogen peroxide, nitric oxide and hypohalous acids that modify and inactivate cellular macromolecules, resulting in growth defects or death. When S. aureus colonization cannot be cleared by the immune system, antibiotic treatment is necessary and can be effective. Yet, this organism quickly gains resistance to each new antibiotic it encounters. Therefore, it is in the interest of human health to acquire a deeper understanding of how S. aureus evades killing by the immune system. Advances in this field will have implications for the design of future S. aureus treatments that complement and assist the host immune response. In that regard, this review focuses on how S. aureus avoids host-generated oxidative stress, and discusses the mechanisms used by S. aureus to survive oxidative damage including antioxidants, direct repair of damaged proteins, sensing oxidant stress and transcriptional changes. This review will elucidate areas for studies to identify and validate future antimicrobial targets. PMID:27354296

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

Current methodologies on genotyping for nosocomial pathogen methicillin-resistant Staphylococcus aureus (MRSA).

PubMed

Miao, Jian; Chen, Lequn; Wang, Jingwen; Wang, Wenxin; Chen, Dingqiang; Li, Lin; Li, Bing; Deng, Yang; Xu, Zhenbo

2017-06-01

Methicillin-resistant Staphylococcus aureus (MRSA) is a common pathogen in hospitals and the community. As the rapid spread and wide distribution of antimicrobial resistance (such as MRSA), treatment for infectious diseases caused by microorganisms has become a vital threat. Thus, early identification and genotyping are essential for further therapeutic treatment and the control of rapid expansion of MRSA. In combination with applications and data feedbacks, this review focused on the currently available molecular-based assays on their utility and performance for rapid typing of MRSA, especially on effective molecular-based methods. Besides, a common mobile element SCCmec and prevalence of HA-MRSA, LA-MRSA and CA-MRSA were introduced in this review in order to provide a more complete profile of MRSA. Copyright © 2017 Elsevier Ltd. All rights reserved.

Inactivation of Staphylococcus aureus and Salmonella enteritidis in tryptic soy broth and caviar samples by high pressure processing.

PubMed

Fioretto, F; Cruz, C; Largeteau, A; Sarli, T A; Demazeau, G; El Moueffak, A

2005-08-01

We studied the action of high pressure processing on the inactivation of two foodborne pathogens, Staphylococcus aureus ATCC 6538 and Salmonella enteritidis ATCC 13076, suspended in a culture medium and inoculated into caviar samples. The baroresistance of the two pathogens in a tryptic soy broth suspension at a concentration of 10(8)-10(9) colony-forming units/ml was tested for continuous and cycled pressurization in the 150- to 550-MPa range and for 15-min treatments at room temperature. The increase of cycle number permitted the reduction of the pressure level able to totally inactivate both microorganisms in the tryptic soy broth suspension, whereas the effect of different procedure times on complete inactivation of the microorganisms inoculated into caviar was similar.

Surveillance of bacteriological examinations at hospitalization in a pediatric surgical ward.

PubMed

Ohno, Koichi; Nakamura, Tetsuro; Azuma, Takashi; Yoshida, Tatsuyuki; Yamada, Hiroto; Hayashi, Hiroaki; Masahata, Kazunori

2008-08-01

Bacteriological examinations at hospitalization were monitored to identify carriers of pathogenic bacteria and prevent the outbreak of nosocomial and postoperative infections. In 557 patients, bacteriological examinations were performed within 48 hours after hospitalization. All people were instructed to wash their hands before and after treating carriers of methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant Staphylococcus epidermidis (MRSE), and/or Pseudomonas aeruginosa (PA). The disposal of stool and urine of carriers was segregated instead of administration of sensitive antibiotics. The 1176 samples comprised 557 throat swabs, 532 stool samples, and 87 other samples. At hospitalization, 9.2% of the patients were carriers of MRSA; 22.3% of the patients were carriers of MRSA, MRSE, PA, and/or other pathogenic bacteria. This percentage increased to 29.3% in 352 patients with a history of hospitalization, and 35.2% in 244 patients who were hospitalized within 1 year after previous hospitalization. Nosocomial and postoperative infections did not occur during the study period. Many patients were detected as carriers of pathogenic bacteria at hospitalization. A history of hospitalization was found to be a risk factor for carrying pathogenic bacteria; hospitalization within 1 year after previous hospitalization was a high-risk factor.

[The microbiology and antimicrobial susceptibility of the infected knee arthroplasty].

PubMed

Peng, Hui-ming; Weng, Xi-sheng; Zhai, Ji-liang; Bian, Yan-yan; Lin, Jin; Jin, Jin; Qian, Wen-wei; Zhao, Li-juang

2013-05-01

To describe the microbiology, antimicrobial susceptibility of patients proven prosthetic joint infection (PJI) after primary total knee arthroplasty (TKA)and to provide reference for the diagnosis and treatment of this complication. The medical data of the patients with infected knee arthroplasty, who were managed with revision surgery between January 1995 to December 2011 were reviewed. Twenty-nine cases were identified and majority of the patients were female (23/29). Diagnosis of PJI after primary TKA was between 1 week and 10 years (average 24.3 months). The microbiology and antimicrobial susceptibility were analyzed. The overall positive rate of cultures was 65.5% (19/29). The most common organisms identified were Coagulase-negative Staphylococcus (CNS) (7/19) and Staphylococcus Aureus (SA) (5/19). Rare pathogens of Mycobacterium (2/19) and fungi (1/19) were also identified. Vancomycin was the most effective antibiotics with overall sensitivity rates of 100%.Resistant and rare pathogens were all in type IV infection. Gram-positive bacterias are the main pathogen, resistant and rare pathogens should be payed attention to. Antibiotic treatment for infected TKA should be based on the results of drug susceptibility. Vancomycin allows infected knee arthroplasties before the result.

Isolation and identification of Staphylococcus sp. in powdered infant milk

NASA Astrophysics Data System (ADS)

Palilu, Prayolga Toban; Budiarso, Tri Yahya

2017-05-01

Staphylococcus sp. is one of the most dangerous bacteria that could cause food poisoning. It is a pathogenic bacterium which is able to produce enterotoxin in foods. Milk is an ideal growth medium for Staphylococcus sp., that may cause problem if it is to be consumed, especially by infant. It is the objective of this research to detect the presence of Staphylococcus sp. in powdered infant milk. As many as 14 samples obtained from market were used as samples for bacterial isolation. The isolation were done by employing enrichment step on BHI-broth, continued with Baird-Parker Agar which will produce a typical colony. It is then picked and grown on Mannitol Salt Agar, and gram staining, coagulase assay, and fermentation tests. The confirmation step was done by using API-Staph which gives the identification of Staphylococcus hemoliticus, Staphylococcus aureus and Staphylococcus epidermidis, with a percentage of identity ranging from 65.9-97.7%. Two isolates with the highest identification similarity values were then picked for molecular detection. A PCR primer pair targeting gene coding for enterotoxin A was used, and it gives positive result for the two isolates being tested. It is then concluded that the two isolates belong to Staphylococcus sp., and further research need to be done to correctly identify these isolates.

Effect of Ultraviolet Light Irradiation Combined with Riboflavin on Different Bacterial Pathogens from Ocular Surface Infection.

PubMed

Shen, Jing; Liang, Qingfeng; Su, Guanyu; Zhang, Yang; Wang, Zhiqun; Liang, Hong; Baudouin, Christophe; Labbé, Antoine

2017-01-01

In order to study Staphylococcus epidermis and Staphylococcus aureus in vitro viability after the exposure to ultraviolet (UV) light and riboflavin, twelve strains of Staphylococcus epidermis and twelve strains of Staphylococcus aureus were isolated from patients with bacterial keratitis. The growth situation of Staphylococcus epidermidis and Staphylococcus aureus under different experimental conditions was qualitatively observed. The number of colonies surviving bacteria was counted under different UV light power and different exposure time. The experiment showed that there was no inhibition effect on the growth of bacteria using riboflavin alone. In UV alone group and UV-riboflavin group, inhibition effect on the bacteria growth was found. The UV-riboflavin combination had better inhibition effect on bacteria than UV irradiation alone. The amount of bacteria in the UV-riboflavin group was decreased by 99.1%~99.5% and 54.8%~64.6% in the UV alone group, when the UV light power was 10.052 mW/cm 2 and the irradiation time was 30 min. Moreover, with the increase of the UV power or irradiation time, the survival rates of bacteria were rapidly reduced. Compared with Staphylococcus aureus , Staphylococcus epidermis was more easily to be killed under the action of UV light combined with riboflavin.

Closely related methicillin-resistant Staphylococcus aureus isolates from retail meat, cows with mastitis, and humans in Japan.

PubMed

Sato, Tomomi; Usui, Masaru; Konishi, Noriko; Kai, Akemi; Matsui, Hidehito; Hanaki, Hideaki; Tamura, Yutaka

2017-01-01

Methicillin-resistant Staphylococcus aureus (MRSA) is a pervasive healthcare-acquired (HA) pathogen with recent emergence as a community-acquired (CA) pathogen. To elucidate whether meat mediates MRSA transmission between animals and humans in Japan, this study examined MRSA isolates from retail meat (n = 8), cows with mastitis (n = 7), and humans (HA-MRSA = 46 and CA-MRSA = 54) by molecular typing, virulence gene analyses, and antimicrobial susceptibility testing. MRSA isolates from retail meat were classified into sequence type (ST) 8/spa type t1767 (n = 4), ST8/t4133 (n = 1), ST59/t3385 (n = 1), ST88/t375 (n = 1), and ST509/t375 (n = 1). All seven MRSA isolates from cows with mastitis were ST8/t1767. 46 HA-MRSA were clonal complex (CC) 5, divided into t002 (n = 30), t045 (n = 12), and t7455 (n = 4). 54 CA-MRSA were classified into 6 different CCs: CC1 (n = 14), CC5 (n = 7), CC8 (n = 29), CC45 (n = 1), CC89 (n = 1), CC509 (n = 1), and into 16 different spa types including newly identified t17177, t17193, and t17194. The majority were CC8/t1767 (n = 16). CC of one CA-MRSA isolate (spa type t1767) was not classified. Among 41 CC8 MRSA (five from meat, seven from cows with mastitis, and 29 CA-MRSA), 14 ST8/SCCmec IVl isolates (three from meat, one from a cow with mastitis, and 10 CA-MRSA) had identical pulsed-field gel electrophoresis patterns and similar spa type (t1767, t4133, and t17177), and were typed as CA-MRSA/J (ST8/SCCmec IVl, positive for sec + sel + tst but negative for Panton-Valentine leukocidin and the arginine catabolic mobile element). These results suggest that there is a transmission cycle of CA-MRSA/J among meat, cows, and humans in Japan, although it is unclear whether the origin is cow.

Closely related methicillin-resistant Staphylococcus aureus isolates from retail meat, cows with mastitis, and humans in Japan

PubMed Central

Konishi, Noriko; Kai, Akemi; Matsui, Hidehito; Hanaki, Hideaki

2017-01-01

Methicillin-resistant Staphylococcus aureus (MRSA) is a pervasive healthcare-acquired (HA) pathogen with recent emergence as a community-acquired (CA) pathogen. To elucidate whether meat mediates MRSA transmission between animals and humans in Japan, this study examined MRSA isolates from retail meat (n = 8), cows with mastitis (n = 7), and humans (HA-MRSA = 46 and CA-MRSA = 54) by molecular typing, virulence gene analyses, and antimicrobial susceptibility testing. MRSA isolates from retail meat were classified into sequence type (ST) 8/spa type t1767 (n = 4), ST8/t4133 (n = 1), ST59/t3385 (n = 1), ST88/t375 (n = 1), and ST509/t375 (n = 1). All seven MRSA isolates from cows with mastitis were ST8/t1767. 46 HA-MRSA were clonal complex (CC) 5, divided into t002 (n = 30), t045 (n = 12), and t7455 (n = 4). 54 CA-MRSA were classified into 6 different CCs: CC1 (n = 14), CC5 (n = 7), CC8 (n = 29), CC45 (n = 1), CC89 (n = 1), CC509 (n = 1), and into 16 different spa types including newly identified t17177, t17193, and t17194. The majority were CC8/t1767 (n = 16). CC of one CA-MRSA isolate (spa type t1767) was not classified. Among 41 CC8 MRSA (five from meat, seven from cows with mastitis, and 29 CA-MRSA), 14 ST8/SCCmec IVl isolates (three from meat, one from a cow with mastitis, and 10 CA-MRSA) had identical pulsed-field gel electrophoresis patterns and similar spa type (t1767, t4133, and t17177), and were typed as CA-MRSA/J (ST8/SCCmec IVl, positive for sec + sel + tst but negative for Panton–Valentine leukocidin and the arginine catabolic mobile element). These results suggest that there is a transmission cycle of CA-MRSA/J among meat, cows, and humans in Japan, although it is unclear whether the origin is cow. PMID:29084288

Clinical relevance of the ESKAPE pathogens.

PubMed

Pendleton, Jack N; Gorman, Sean P; Gilmore, Brendan F

2013-03-01

In recent years, the Infectious Diseases Society of America has highlighted a faction of antibiotic-resistant bacteria (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp.) - acronymically dubbed 'the ESKAPE pathogens' - capable of 'escaping' the biocidal action of antibiotics and mutually representing new paradigms in pathogenesis, transmission and resistance. This review aims to consolidate clinically relevant background information on the ESKAPE pathogens and provide a contemporary summary of bacterial resistance, alongside pertinent microbiological considerations necessary to face the mounting threat of antimicrobial resistance.

The first case report of non-nosocomial healthcare-associated infective endocarditis due to methicillin-resistant Staphylococcus aureus USA400 in Rio de Janeiro, Brazil.

PubMed

Damasco, P V; Cavalcante, F S; Chamon, R C; Ferreira, D C; Rioja, S S; Potsch, M V; Pastura, M P; Marques, V D; Castier, M B; Marques, E A; Santos, K R N

2013-08-01

Staphylococcus aureus is the main causal pathogen of infective endocarditis (IE), which may have distinct origins, namely, community, nosocomial, or non-nosocomial healthcare-associated (NNHCA). We report the first case of NNHCA-IE caused by methicillin-resistant S. aureus strain USA400/SCCmec IV in which the combination therapy of rifampin and vancomycin had a favorable outcome for the patient.

Current studies on bacterospermia the leading cause of male infertility: a protégé and potential threat towards mans extinction.

PubMed

Isaiah, Ibeh Nnana; Nche, Bikwe Thomas; Nwagu, Ibeh Georgina; Nnanna, Ibeh Isaiah

2011-12-01

The current rise of male infertility associated with bacterospermia and urogenital infection has been on the increase amongst adult married males in Benin metropolis and a major cause of concern to male fertility and reproduction in Nigeria. To microbiologically isolate and study the infectious agent that has led to male infertility and also to study the percentage occurrence of bacteropsermia and urogenital caused infertility in adult married males in Benin metropolis using standard microbiological methods of isolating and identifying the organism, specimen was collected and processed which includes the susceptibility profile of isolates and sperm quality. In this study a total of 140 sperm samples was collected from patient who were referred from the consultant outpatient department of the University of Benin Teaching Hospital and then evaluated bacteriologically using standard bacterial cultural methods Among the total cases, 92 (65.7%) showed at least one pathogen. Staphylococcus aureus (28.3%), Staphylococcus Saprophyticus (13.0%), Pseudomonas aerouginosa (6.5%), Escherichia Coli (19.6%) Proteus mirabilis (10.8%) Klebsiella spp (10.8%) and Proteus vulgaris (10.8%). There was an outstanding significant relationship between bacteriospermia and the rate of total motility and morphologically abnormal sperms, The percentage of morphologically normal sperm was lower in this study. Staphylococcus aureus Staphylococcus saprohyticus and Escherichia coli were the most common pathogen having negative effects on sperm motility and morphology in this study.

Induction of Attachment-Independent Biofilm Formation and Repression of hfq Expression by Low-Fluid-Shear Culture of Staphylococcus aureus ▿

PubMed Central

Castro, Sarah L.; Nelman-Gonzalez, Mayra; Nickerson, Cheryl A.; Ott, C. Mark

2011-01-01

The opportunistic pathogen Staphylococcus aureus encounters a wide variety of fluid shear levels within the human host, and they may play a key role in dictating whether this organism adopts a commensal interaction with the host or transitions to cause disease. By using rotating-wall vessel bioreactors to create a physiologically relevant, low-fluid-shear environment, S. aureus was evaluated for cellular responses that could impact its colonization and virulence. S. aureus cells grown in a low-fluid-shear environment initiated a novel attachment-independent biofilm phenotype and were completely encased in extracellular polymeric substances. Compared to controls, low-shear-cultured cells displayed slower growth and repressed virulence characteristics, including decreased carotenoid production, increased susceptibility to oxidative stress, and reduced survival in whole blood. Transcriptional whole-genome microarray profiling suggested alterations in metabolic pathways. Further genetic expression analysis revealed downregulation of the RNA chaperone Hfq, which parallels low-fluid-shear responses of certain Gram-negative organisms. This is the first study to report an Hfq association with fluid shear in a Gram-positive organism, suggesting an evolutionarily conserved response to fluid shear among structurally diverse prokaryotes. Collectively, our results suggest S. aureus responds to a low-fluid-shear environment by initiating a biofilm/colonization phenotype with diminished virulence characteristics, which could lead to insight into key factors influencing the divergence between infection and colonization during the initial host-pathogen interaction. PMID:21803898

First description of PVL-positive methicillin-resistant Staphylococcus aureus (MRSA) in wild boar meat.

PubMed

Kraushaar, Britta; Fetsch, Alexandra

2014-09-01

Staphylococcus aureus is an important food-borne pathogen due to the ability of enterotoxigenic strains to produce staphylococcal enterotoxins (SEs) in food. Methicillin-resistant S. aureus (MRSA) is also an important pathogen for humans, causing severe and hard to treat diseases in hospitals and in the community due to its multiresistance against antimicrobials. In particular, strains harbouring genes encoding for the Panton-Valentine leukocidin (PVL) toxin are of concern from a public health perspective as they are usually capable of causing severe skin and soft tissue infections (sSSTIs) and occasionally necrotizing pneumonia which is associated with high mortality. This is the first report on the detection of MRSA with genes encoding for PVL in wild boar meat. Among the 28 MRSA isolated from wild boar meat in the course of a national monitoring programme in Germany, seven harboured PVL-encoding genes. Six of the isolates were identical according to the results of spa-, MLST-, microarray- and PFGE-typing. They could be assigned to the epidemic MRSA clone USA300. Epidemiological investigations revealed that people handling the food were the most likely common source of contamination with these MRSA. These findings call again for suitable hygienic measures at all processing steps of the food production chain. The results of the study underline that monitoring along the food chain is essential to closely characterise the total burden of MRSA for public health. Copyright © 2014. Published by Elsevier B.V.

Carnobacterium divergens - a dominating bacterium of pork meat juice.

PubMed

Rieder, Gabriele; Krisch, Linda; Fischer, Harald; Kaufmann, Maria; Maringer, Adolf; Wessler, Silja

2012-07-01

Nonspoiled food that nevertheless contains bacterial pathogens constitutes a much more serious health problem than spoiled food, as the consumer is not warned beforehand. However, data on the diversity of bacterial species in meat juice are rare. To study the bacterial load of fresh pork from ten different distributors, we applied a combination of the conventional culture-based and molecular methods for detecting and quantifying the microbial spectrum of fresh pork meat juice samples. Altogether, we identified 23 bacterial species of ten different families analyzed by 16S rRNA gene sequencing. The majority of isolates were belonging to the typical spoilage bacterial population of lactic acid bacteria (LAB), Enterococcaceae, and Pseudomonadaceae. Several additional isolates were identified as Staphylococcus spp. and Bacillus spp. originating from human and animal skin and other environmental niches including plants, soil, and water. Carnobacterium divergens, a LAB contributing to the spoilage of raw meat even at refrigeration temperature, was the most frequently isolated species in our study (5/10) with a bacterial load of 10(3) - 10(7) CFU mL(-1). In several of the analyzed pork meat juice samples, two bacterial faecal indicators, Serratia grimesii and Serratia proteamaculans, were identified together with another opportunistic food-borne pathogen, Staphylococcus equorum. Our data reveal a high bacterial load of fresh pork meat supporting the potential health risk of meat juice for the end consumer even under refrigerated conditions. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Assessment of Fecal Indicator Bacteria and Potential Pathogen Co-Occurrence at a Shellfish Growing Area

PubMed Central

Leight, Andrew K.; Crump, Byron C.; Hood, Raleigh R.

2018-01-01

Routine monitoring of shellfish growing waters for bacteria indicative of human sewage pollution reveals little about the bacterial communities that co-occur with these indicators. This study investigated the bacterial community, potential pathogens, and fecal indicator bacteria in 40 water samples from a shellfish growing area in the Chesapeake Bay, USA. Bacterial community composition was quantified with deep sequencing of 16S rRNA gene amplicons, and absolute gene abundances were estimated with an internal standard (Thermus thermophilus genomes). Fecal coliforms were quantified by culture, and Vibrio vulnificus and V. parahaemolyticus with quantitative PCR. Fecal coliforms and V. vulnificus were detected in most samples, and a diverse assemblage of potential human pathogens were detected in all samples. These taxa followed two general patterns of abundance. Fecal coliforms and 16S rRNA genes for Enterobacteriaceae, Aeromonas, Arcobacter, Staphylococcus, and Bacteroides increased in abundance after a 1.3-inch rain event in May, and, for some taxa, after smaller rain events later in the season, suggesting that these are allochthonous organisms washed in from land. Clostridiaceae and Mycobacterium 16S rRNA gene abundances increased with day of the year and were not positively related to rainfall, suggesting that these are autochthonous organisms. Other groups followed both patterns, such as Legionella. Fecal coliform abundance did not correlate with most other taxa, but were extremely high following the large rainstorm in May when they co-occurred with a broad range of potential pathogen groups. V. vulnificus were absent during the large rainstorm, and did not correlate with 16S rRNA abundances of Vibrio spp. or most other taxa. These results highlight the complex nature of bacterial communities and the limited utility of using specific bacterial groups as indicators of pathogen presence. PMID:29593669

Lactic acid bacterial symbionts in honeybees - an unknown key to honey's antimicrobial and therapeutic activities.

PubMed

Olofsson, Tobias C; Butler, Èile; Markowicz, Pawel; Lindholm, Christina; Larsson, Lennart; Vásquez, Alejandra

2016-10-01

Could honeybees' most valuable contribution to mankind besides pollination services be alternative tools against infections? Today, due to the emerging antibiotic-resistant pathogens, we are facing a new era of searching for alternative tools against infections. Natural products such as honey have been applied against human's infections for millennia without sufficient scientific evidence. A unique lactic acid bacterial (LAB) microbiota was discovered by us, which is in symbiosis with honeybees and present in large amounts in fresh honey across the world. This work investigates if the LAB symbionts are the source to the unknown factors contributing to honey's properties. Hence, we tested the LAB against severe wound pathogens such as methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa and vancomycin-resistant Enterococcus (VRE) among others. We demonstrate a strong antimicrobial activity from each symbiont and a synergistic effect, which counteracted all the tested pathogens. The mechanisms of action are partly shown by elucidating the production of active compounds such as proteins, fatty acids, anaesthetics, organic acids, volatiles and hydrogen peroxide. We show that the symbionts produce a myriad of active compounds that remain in variable amounts in mature honey. Further studies are now required to investigate if these symbionts have a potential in clinical applications as alternative tools against topical human and animal infections. © 2014 The Authors. International Wound Journal published by Medicalhelplines.com Inc and John Wiley & Sons Ltd.

[Prevalence and features of pathogenic bacteria in the department of hematology without bone marrow transplantation in Peking Union Medical College Hospital from 2010 to 2012].

PubMed

Wnag, Lu; Yang, Chen; Zhang, Qian; Han, Bing; Zhuang, Jun-jing; Chen, Miao; Zou, Nong; Li, Jian; Duan, Ming-hui; Zhang, Wei; Zhu, Tie-nan; Xu, Ying; Wang, Shu-jie; Zhou, Dao-bin; Zhao, Yong-qiang; Zhang, Hui; Wang, Peng; Xu, Ying-chun

2014-08-01

To investigate the incidence, pathogens, and clinical features of infection in consecutive cases from 2010 to 2012 in Peking Union Medical College Hospital. The incidence, pathogen, treatment, and outcomes of patients with hematological diseases who had positive findings of bacterium in their samples from 2010 to 2012 were retrospectively analyzed. There were 449 positive samples (5.8%) from 4 890 patients during this period, among which 388 were proved to be with pathogenic bacteria. Samples separated from patients with community-aquired infections accounted for 8.4% of all positive samples. Most community-aquired infections were caused by Gram-negative bacteria (75%), although no multidrug-resistant bacteria was observed. Samples separated from patients with nosocomial infections accounted for 91.6% of all positive samples. Respiratory tract (49.4%) and peripheral blood (32.6%) were the most common samples with positive results. Skin soft tissues (10.4%), and urine (3.7%) were less common samples. Most of the pathogenic bacteria of the nosocomial infections were Gram-negative (66.9%). The most common Gram-negative bacteria included Escherichia coli (13.8%), Pseudomonas aeruginosa (12.1%), and Klebsiella pneumonia (12.1%), while Staphylococcus aureus (10.4%), Enterococcus faecium (7.0%), and Staphylococcus epidermidis (5.1%) were the most common Gram-positive bacteria. Gram-negative bacteria consisted of most of sputum samples and peripheral blood samples. Samples from the surface of skin wound and anal swab were composed largely by Gram-positive bacteria (63.8%). The detection rates of extended-spectrum beta-lactamase-producing Klebsiella pneumonia/Klebsiella oxytoca, Escherichia coli, and Proteus mirabilis were 24.0%, 87.9% and 38.4%, respectively. The resistance to Acinetobacter baumannii was serious. Multidrug-resistant, extensive drug resistant and pan drug resistant A. baumannii acountted for 74% of all A. Baumannii infections. Stenotrophomonas maltophilia showed low resistance to sulfamethoxazole/trimethoprim, levofloxacin and minocycline. Also, 22 methicillin-resistant Staphylococcus aureus and 9 methicillin-resistant Staphylococcus Epidermidis were detected, which were only sensitive to vancomycin, teicoplanin, and linezolid. All patients were treated in the haematology wards and most of them were under agranulocytosis or immunosuppression. Finally, 22 patients reached clinical recovery through anti-infective therapy, whereas 49 patients died. Among those deaths, 42 patients attributed to severe infections and infection-associated complications. Fourteen of all the deaths might be infected with drug-resistance bacteria. There were 61 samples proved to be bacteria colonization. Nonfermenters such as Acinetobacter baumannii and Stenotrophomonas maltophilia made up for a large amount of bacteria colonization. The pathogens of nosocomial infections in the hematology ward are mainly Gram-negative bacteria. The incidences and pathogens vary from different infection sites. Nosocomial infection still has a higher mortality rate. Once nonfermenters are detected positive, the pathogenic or colonial bacteria should be distinguished.

Staphylococcus haemolyticus prophage ΦSH2 endolysin relies on Cysteine, Histidine-dependent Amidohydrolases/Peptidases activity for lysis ‘from without’

PubMed Central

Schmelcher, Mathias; Korobova, Olga; Schischkova, Nina; Kiseleva, Natalia; Kopylov, Paul; Pryamchuk, Sergey; Donovan, David M.; Abaev, Igor

2014-01-01

Staphylococcus aureus is an important pathogen, with methicillin-resistant (MRSA) and multi-drug resistant strains becoming increasingly prevalent in both human and veterinary clinics. S. aureus causing bovine mastitis yields high annual losses to the dairy industry. Conventional treatment of mastitis by broad range antibiotics is often not successful and may contribute to development of antibiotic resistance. Bacteriophage endolysins present a promising new source of antimicrobials. The endolysin of prophage ΦSH2 of Staphylococcus haemolyticus strain JCSC1435 (ΦSH2 lysin) is a peptidoglycan hydrolase consisting of two catalytic domains (CHAP and amidase) and an SH3b cell wall binding domain. In this work, we demonstrated its lytic activity against live staphylococcal cells and investigated the contribution of each functional module to bacterial lysis by testing a series of deletion constructs in zymograms and turbidity reduction assays. The CHAP domain exhibited three-fold higher activity than the full length protein and optimum activity in physiological saline. This activity was further enhanced by the presence of bivalent calcium ions. The SH3b domain was shown to be required for full activity of the complete ΦSH2 lysin. The full length enzyme and the CHAP domain showed activity against multiple staphylococcal strains, including MRSA strains, mastitis isolates, and CoNS. PMID:23026556

Staphylococcus haemolyticus prophage ΦSH2 endolysin relies on cysteine, histidine-dependent amidohydrolases/peptidases activity for lysis 'from without'.

PubMed

Schmelcher, Mathias; Korobova, Olga; Schischkova, Nina; Kiseleva, Natalia; Kopylov, Paul; Pryamchuk, Sergey; Donovan, David M; Abaev, Igor

2012-12-31

Staphylococcus aureus is an important pathogen, with methicillin-resistant (MRSA) and multi-drug resistant strains becoming increasingly prevalent in both human and veterinary clinics. S. aureus causing bovine mastitis yields high annual losses to the dairy industry. Conventional treatment of mastitis by broad range antibiotics is often not successful and may contribute to development of antibiotic resistance. Bacteriophage endolysins present a promising new source of antimicrobials. The endolysin of prophage ΦSH2 of Staphylococcus haemolyticus strain JCSC1435 (ΦSH2 lysin) is a peptidoglycan hydrolase consisting of two catalytic domains (CHAP and amidase) and an SH3b cell wall binding domain. In this work, we demonstrated its lytic activity against live staphylococcal cells and investigated the contribution of each functional module to bacterial lysis by testing a series of deletion constructs in zymograms and turbidity reduction assays. The CHAP domain exhibited three-fold higher activity than the full length protein and optimum activity in physiological saline. This activity was further enhanced by the presence of bivalent calcium ions. The SH3b domain was shown to be required for full activity of the complete ΦSH2 lysin. The full length enzyme and the CHAP domain showed activity against multiple staphylococcal strains, including MRSA strains, mastitis isolates, and CoNS. Published by Elsevier B.V.

The impact of Staphylococcus aureus-associated molecular patterns on staphylococcal superantigen-induced toxic shock syndrome and pneumonia.

PubMed

Tilahun, Ashenafi Y; Karau, Melissa; Ballard, Alessandro; Gunaratna, Miluka P; Thapa, Anusa; David, Chella S; Patel, Robin; Rajagopalan, Govindarajan

2014-01-01

Staphylococcus aureus is capable of causing a spectrum of human illnesses. During serious S. aureus infections, the staphylococcal pathogen-associated molecular patterns (PAMPs) such as peptidoglycan, lipoteichoic acid, and lipoproteins and even intact S. aureus, are believed to act in conjunction with the staphylococcal superantigens (SSAg) to activate the innate and adaptive immune system, respectively, and cause immunopathology. However, recent studies have shown that staphylococcal PAMPs could suppress inflammation by several mechanisms and protect from staphylococcal toxic shock syndrome, a life-threatening systemic disease caused by toxigenic S. aureus. Given the contradictory pro- and anti-inflammatory roles of staphylococcal PAMPs, we examined the effects of S. aureus-derived molecular patterns on immune responses driven by SSAg in vivo using HLA-DR3 and HLA-DQ8 transgenic mice. Our study showed that neither S. aureus-derived peptidoglycans (PGN), lipoteichoic acid (LTA), nor heat-killed Staphylococcus aureus (HKSA) inhibited SSAg-induced T cell proliferation in vitro. They failed to antagonize the immunostimulatory effects of SSAg in vivo as determined by their inability to attenuate systemic cytokine/chemokine response and reduce SSAg-induced T cell expansion. These staphylococcal PAMPs also failed to protect HLA-DR3 as well as HLA-DQ8 transgenic mice from either SSAg-induced toxic shock or pneumonia induced by a SSAg-producing strain of S. aureus.

Microbial Air and Surface Monitoring Results from International Space Station Samples

NASA Technical Reports Server (NTRS)

Ott, C. Mark; Bruce, Rebekah J.; Castro, Victoria A.; Novikova, Natalia D.; Pierson, D. L.

2005-01-01

Over the course of long-duration spaceflight, spacecraft develop a microbial ecology that directly interacts with the crew of the vehicle. While most microorganisms are harmless or beneficial to the inhabitants of the vehicle, the presence of medically significant organisms appearing in this semi-closed environment could adversely affect crew health and performance. The risk of exposure of the crew to medically significant organisms during a mission is estimated using information gathered during nominal and contingency environmental monitoring. Analysis of the air and surface microbiota in the habitable compartments of the International Space Station (ISS) over the last four years indicate a high presence of Staphylococcus species reflecting the human inhabitants of the vehicle. Generally, air and surface microbial concentrations are below system design specifications, suggesting a lower risk of contact infection or biodegradation. An evaluation of sample frequency indicates a decrease in the identification of new species, suggesting a lower potential for unknown microorganisms to be identified. However, the opportunistic pathogen, Staphylococcus aureus, has been identified in 3 of the last 5 air samples and 5 of the last 9 surface samples. In addition, 47% of the coagulase negative Staphylococcus species that were isolated from the crew, ISS, and its hardware were found to be methicillin resistance. In combination, these observations suggest the potential of methicillin resistant infectious agents over time.

Identification of Staphylococcus saprophyticus isolated from patients with urinary tract infection using a simple set of biochemical tests correlating with 16S-23S interspace region molecular weight patterns.

PubMed

Ferreira, Adriano Martison; Bonesso, Mariana Fávero; Mondelli, Alessandro Lia; da Cunha, Maria de Lourdes Ribeiro de Souza

2012-12-01

The emergence of Staphylococcus spp. not only as human pathogens, but also as reservoirs of antibiotic resistance determinants, requires the development of methods for their rapid and reliable identification in medically important samples. The aim of this study was to compare three phenotypic methods for the identification of Staphylococcus spp. isolated from patients with urinary tract infection using the PCR of the 16S-23S interspace region generating molecular weight patterns (ITR-PCR) as reference. All 57 S. saprophyticus studied were correctly identified using only the novobiocin disk. A rate of agreement of 98.0% was obtained for the simplified battery of biochemical tests in relation to ITR-PCR, whereas the Vitek I system and novobiocin disk showed 81.2% and 89.1% agreement, respectively. No other novobiocin-resistant non-S. saprophyticus strain was identified. Thus, the novobiocin disk is a feasible alternative for the identification of S. saprophyticus in urine samples in laboratories with limited resources. ITR-PCR and the simplified battery of biochemical tests were more reliable than the commercial systems currently available. This study confirms that automated systems are still unable to correctly differentiate CoNS species and that simple, reliable and inexpensive methods can be used for routine identification. Copyright © 2012 Elsevier B.V. All rights reserved.

In vitro assay of Staphylococcus aureus enterotoxin A activity in food.

PubMed Central

Rasooly, L; Rose, N R; Shah, D B; Rasooly, A

1997-01-01

Staphylococcus aureus enterotoxin A (SEA) is a leading cause of food poisoning. The current test for functional activity of SEA requires monkeys or kittens. The major drawbacks of animal assays are lack of quantitation, poor reproducibility, low sensitivity, and high cost. In this report we describe and evaluate an alternative assay using T-cell proliferation to measure SEA activity in food. Human and rat lymphocytes proliferate in response to concentrations of SEA as low as 1 pg/ml, well below the pathogenic dose of 100 ng. This proliferation assay is highly sensitive, quantitative, and simple. Nonradioactive assays of T-cell proliferation were also suitable for detecting and measuring SEA, although with a 10-fold lower sensitivity. To evaluate the utility of this assay for food testing, four different food samples were mixed with SEA. In each sample, SEA was detected at a concentration of 1 ng/ml. Heat-inactivated SEA produced no detectable proliferation. These results demonstrate that an in vitro cell proliferation assay is an advantageous alternative to existing animal assays for measuring SEA activity in food. PMID:9172356

Structural basis of Staphylococcus epidermidis biofilm formation: mechanisms and molecular interactions

PubMed Central

Büttner, Henning; Mack, Dietrich; Rohde, Holger

2015-01-01

Staphylococcus epidermidis is a usually harmless commensal bacterium highly abundant on the human skin. Under defined predisposing conditions, most importantly implantation of a medical device, S. epidermidis, however, can switch from a colonizing to an invasive life style. The emergence of S. epidermidis as an opportunistic pathogen is closely linked to the biofilm forming capability of the species. During the past decades, tremendous advance regarding our understanding of molecular mechanisms contributing to surface colonization has been made, and detailed information is available for several factors active during the primary attachment, accumulative or dispersal phase of biofilm formation. A picture evolved in which distinct factors, though appearing to be redundantly organized, take over specific and exclusive functions during biofilm development. In this review, these mechanisms are described in molecular detail, with a highlight on recent insights into multi-functional S. epidermidis cell surface proteins contributing to surface adherence and intercellular adhesion. The integration of distinct biofilm-promoting factors into regulatory networks is summarized, with an emphasis on mechanism that could allow S. epidermidis to flexibly adapt to changing environmental conditions present during colonizing or invasive life-styles. PMID:25741476

A nanoparticulate injectable hydrogel as a tissue engineering scaffold for multiple growth factor delivery for bone regeneration.

PubMed

Dyondi, Deepti; Webster, Thomas J; Banerjee, Rinti

2013-01-01

Gellan xanthan gels have been shown to be excellent carriers for growth factors and as matrices for several tissue engineering applications. Gellan xanthan gels along with chitosan nanoparticles of 297 ± 61 nm diameter, basic fibroblast growth factor (bFGF), and bone morphogenetic protein 7 (BMP7) were employed in a dual growth factor delivery system to promote the differentiation of human fetal osteoblasts. An injectable system with ionic and temperature gelation was optimized and characterized. The nanoparticle loaded gels showed significantly improved cell proliferation and differentiation due to the sustained release of growth factors. A differentiation marker study was conducted, analyzed, and compared to understand the effect of single vs dual growth factors and free vs encapsulated growth factors. Dual growth factor loaded gels showed a higher alkaline phosphatase and calcium deposition compared to single growth factor loaded gels. The results suggest that encapsulation and stabilization of growth factors within nanoparticles and gels are promising for bone regeneration. Gellan xanthan gels also showed antibacterial effects against Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis, the common pathogens in implant failure.

Propyl-5-hydroxy-3-methyl-1-phenyl-1H-pyrazole-4-carbodithioate (HMPC): a new bacteriostatic agent against methicillin-resistant Staphylococcus aureus.

PubMed

Johnston, Tatiana; Van Tyne, Daria; Chen, Roy F; Fawzi, Nicolas L; Kwon, Bumsup; Kelso, Michael J; Gilmore, Michael S; Mylonakis, Eleftherios

2018-05-04

The emergence of Staphylococcus aureus strains resistant to 'last resort' antibiotics compels the development of new antimicrobials against this important human pathogen. We found that propyl 5-hydroxy-3-methyl-1-phenyl-1H-pyrazole-4-carbodithioate (HMPC) shows bacteriostatic activity against S. aureus (MIC = 4 μg/ml) and rescues Caenorhabditis elegans from S. aureus infection. Whole-genome sequencing of S. aureus mutants resistant to the compound, along with screening of a S. aureus promoter-lux reporter array, were used to explore possible mechanisms of action. All mutants resistant to HMPC acquired missense mutations at distinct codon positions in the global transcriptional regulator mgrA, followed by secondary mutations in the phosphatidylglycerol lysyltransferase fmtC/mprF. The S. aureus promoter-lux array treated with HMPC displayed a luminescence profile that was unique but showed similarity to DNA-damaging agents and/or DNA replication inhibitors. Overall, HMPC is a new anti-staphylococcal compound that appears to act via an unknown mechanism linked to the global transcriptional regulator MgrA.

Staphylococcus lugdunensis IsdG Liberates Iron from Host Heme▿

PubMed Central

Haley, Kathryn P.; Janson, Eric M.; Heilbronner, Simon; Foster, Timothy J.; Skaar, Eric P.

2011-01-01

Staphylococcus lugdunensis is often found as part of the normal flora of human skin but has the potential to cause serious infections even in healthy individuals. It remains unclear what factors enable S. lugdunensis to transition from a skin commensal to an invasive pathogen. Analysis of the complete genome reveals a putative iron-regulated surface determinant (Isd) system encoded within S. lugdunensis. In other bacteria, the Isd system permits the utilization of host heme as a source of nutrient iron to facilitate bacterial growth during infection. In this study, we establish that S. lugdunensis expresses an iron-regulated IsdG-family heme oxygenase that binds and degrades heme. Heme degradation by IsdG results in the release of free iron and the production of the chromophore staphylobilin. IsdG-mediated heme catabolism enables the use of heme as a sole source of iron, establishing IsdG as a pathophysiologically relevant heme oxygenase in S. lugdunensis. Together these findings offer insight into how S. lugdunensis fulfills its nutritional requirements while invading host tissues and establish the S. lugdunensis Isd system as being involved in heme-iron utilization. PMID:21764939

Mechanisms of antibiotic resistance in Staphylococcus aureus.

PubMed

Pantosti, Annalisa; Sanchini, Andrea; Monaco, Monica

2007-06-01

Staphylococcus aureus can exemplify better than any other human pathogen the adaptive evolution of bacteria in the antibiotic era, as it has demonstrated a unique ability to quickly respond to each new antibiotic with the development of a resistance mechanism, starting with penicillin and methicillin, until the most recent, linezolid and daptomycin. Resistance mechanisms include enzymatic inactivation of the antibiotic (penicillinase and aminoglycoside-modification enzymes), alteration of the target with decreased affinity for the antibiotic (notable examples being penicillin-binding protein 2a of methicillin-resistant S. aureus and D-Ala-D-Lac of peptidoglycan precursors of vancomycin-resistant strains), trapping of the antibiotic (for vancomycin and possibly daptomycin) and efflux pumps (fluoroquinolones and tetracycline). Complex genetic arrays (staphylococcal chromosomal cassette mec elements or the vanA operon) have been acquired by S. aureus through horizontal gene transfer, while resistance to other antibiotics, including some of the most recent ones (e.g., fluoroquinolones, linezolid and daptomycin) have developed through spontaneous mutations and positive selection. Detection of the resistance mechanisms and their genetic basis is an important support to antibiotic susceptibility surveillance in S. aureus.

Identification of structural traits that increase the antimicrobial activity of a chimeric peptide of human β-defensins 2 and 3.

PubMed

Spudy, Björn; Sönnichsen, Frank D; Waetzig, Georg H; Grötzinger, Joachim; Jung, Sascha

2012-10-12

Antimicrobial peptides participate in the first line of defence of many organisms against pathogens. In humans, the family of β-defensins plays a pivotal role in innate immunity. Two human β-defensins, β-defensin-2 and -3 (HBD2 and HBD3), show substantial sequence identity and structural similarity. However, HBD3 kills Staphylococcus (S.) aureus with a 4- to 8-fold higher efficiency compared to HBD2, whereas their activities against Escherichia (E.) coli are very similar. The generation of six HBD2/HBD3-chimeric molecules led to the identification of distinct molecular regions which mediate their divergent killing properties. One of the chimeras (chimera C3) killed both E. coli and S. aureus with an even higher efficacy compared to the wild-type molecules. Due to the broad spectrum of its antimicrobial activity against many human multidrug-resistant pathogens, this HBD2/HBD3-chimeric peptide represents a promising candidate for a new class of antibiotics. In order to investigate the structural basis of its exceptional antimicrobial activity, the peptide's tertiary structure was determined by NMR spectroscopy, which allowed its direct comparison to the published structures of HBD2 and HBD3 and the identification of the activity-increasing molecular features. Copyright © 2012 Elsevier Inc. All rights reserved.

Comparison of microbial DNA enrichment tools for metagenomic whole genome sequencing.

PubMed

Thoendel, Matthew; Jeraldo, Patricio R; Greenwood-Quaintance, Kerryl E; Yao, Janet Z; Chia, Nicholas; Hanssen, Arlen D; Abdel, Matthew P; Patel, Robin

2016-08-01

Metagenomic whole genome sequencing for detection of pathogens in clinical samples is an exciting new area for discovery and clinical testing. A major barrier to this approach is the overwhelming ratio of human to pathogen DNA in samples with low pathogen abundance, which is typical of most clinical specimens. Microbial DNA enrichment methods offer the potential to relieve this limitation by improving this ratio. Two commercially available enrichment kits, the NEBNext Microbiome DNA Enrichment Kit and the Molzym MolYsis Basic kit, were tested for their ability to enrich for microbial DNA from resected arthroplasty component sonicate fluids from prosthetic joint infections or uninfected sonicate fluids spiked with Staphylococcus aureus. Using spiked uninfected sonicate fluid there was a 6-fold enrichment of bacterial DNA with the NEBNext kit and 76-fold enrichment with the MolYsis kit. Metagenomic whole genome sequencing of sonicate fluid revealed 13- to 85-fold enrichment of bacterial DNA using the NEBNext enrichment kit. The MolYsis approach achieved 481- to 9580-fold enrichment, resulting in 7 to 59% of sequencing reads being from the pathogens known to be present in the samples. These results demonstrate the usefulness of these tools when testing clinical samples with low microbial burden using next generation sequencing. Copyright © 2016 Elsevier B.V. All rights reserved.

Automated analysis of food-borne pathogens using a novel microbial cell culture, sensing and classification system.

PubMed

Xiang, Kun; Li, Yinglei; Ford, William; Land, Walker; Schaffer, J David; Congdon, Robert; Zhang, Jing; Sadik, Omowunmi

2016-02-21

We hereby report the design and implementation of an Autonomous Microbial Cell Culture and Classification (AMC(3)) system for rapid detection of food pathogens. Traditional food testing methods require multistep procedures and long incubation period, and are thus prone to human error. AMC(3) introduces a "one click approach" to the detection and classification of pathogenic bacteria. Once the cultured materials are prepared, all operations are automatic. AMC(3) is an integrated sensor array platform in a microbial fuel cell system composed of a multi-potentiostat, an automated data collection system (Python program, Yocto Maxi-coupler electromechanical relay module) and a powerful classification program. The classification scheme consists of Probabilistic Neural Network (PNN), Support Vector Machines (SVM) and General Regression Neural Network (GRNN) oracle-based system. Differential Pulse Voltammetry (DPV) is performed on standard samples or unknown samples. Then, using preset feature extractions and quality control, accepted data are analyzed by the intelligent classification system. In a typical use, thirty-two extracted features were analyzed to correctly classify the following pathogens: Escherichia coli ATCC#25922, Escherichia coli ATCC#11775, and Staphylococcus epidermidis ATCC#12228. 85.4% accuracy range was recorded for unknown samples, and within a shorter time period than the industry standard of 24 hours.

Animal venoms as antimicrobial agents.

PubMed

Perumal Samy, Ramar; Stiles, Bradley G; Franco, Octavio L; Sethi, Gautam; Lim, Lina H K

2017-06-15

Hospitals are breeding grounds for many life-threatening bacteria worldwide. Clinically associated gram-positive bacteria such as Staphylococcus aureus/methicillin-resistant S. aureus and many others increase the risk of severe mortality and morbidity. The failure of antibiotics to kill various pathogens due to bacterial resistance highlights the urgent need to develop novel, potent, and less toxic agents from natural sources against various infectious agents. Currently, several promising classes of natural molecules from snake (terrestrial and sea), scorpion, spider, honey bee and wasp venoms hold promise as rich sources of chemotherapeutics against infectious pathogens. Interestingly, snake venom-derived synthetic peptide/snake cathelicidin not only has potent antimicrobial and wound-repair activity but is highly stable and safe. Such molecules are promising candidates for novel venom-based drugs against S. aureus infections. The structure of animal venom proteins/peptides (cysteine rich) consists of hydrophobic α-helices or β-sheets that produce lethal pores and membrane-damaging effects on bacteria. All these antimicrobial peptides are under early experimental or pre-clinical stages of development. It is therefore important to employ novel tools for the design and the development of new antibiotics from the untapped animal venoms of snake, scorpion, and spider for treating resistant pathogens. To date, snail venom toxins have shown little antibiotic potency against human pathogens. Copyright © 2017 Elsevier Inc. All rights reserved.

Crystal structure of Staphylococcus aureus Zn-glyoxalase I: new subfamily of glyoxalase I family

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

Chirgadze, Yuri N.; Boshkova, Eugenia A.; Battaile, Kevin P.

The crystal structures of protein SA0856 from Staphylococcus aureus in its apo-form and in complex with a Zn2+-ion have been presented. The 152 amino acid protein consists of two similar domains with α + β topology. In both crystalline state and in solution, the protein forms a dimer with monomers related by a twofold pseudo-symmetry rotation axis. A sequence homology search identified the protein as a member of the structural family Glyoxalase I. We have shown that the enzyme possesses glyoxalase I activity in the presence of Zn2+, Mg2+, Ni2+, and Co2+, in this order of preference. Sequence and structuremore » comparisons revealed that human glyoxalase I should be assigned to a subfamily A, while S. aureus glyoxalase I represents a new subfamily B, which includes also proteins from other bacteria. Both subfamilies have a similar protein chain fold but rather diverse sequences. The active sites of human and staphylococcus glyoxalases I are also different: the former contains one Zn-ion per chain; the latter incorporates two of these ions. In the active site of SA0856, the first Zn-ion is well coordinated by His58, Glu60 from basic molecule and Glu40*, His44* from adjacent symmetry-related molecule. The second Zn3-ion is coordinated only by residue His143 from protein molecule and one acetate ion. We suggest that only single Zn1-ion plays the role of catalytic center. The newly found differences between the two subfamilies could guide the design of new drugs against S. aureus, an important pathogenic micro-organism.« less

Label-Free 3D Ag Nanoflower-Based Electrochemical Immunosensor for the Detection of Escherichia coli O157:H7 Pathogens

NASA Astrophysics Data System (ADS)

Huang, He; Liu, Minghuan; Wang, Xiangsheng; Zhang, Wenjie; Yang, Da-Peng; Cui, Lianhua; Wang, Xiansong

2016-11-01

It is highly desirable to develop a rapid and simple method to detect pathogens. Combining nanomaterials with electrochemical techniques is an efficient way for pathogen detection. Herein, a novel 3D Ag nanoflower was prepared via a biomineralization method by using bovine serum albumin (BSA) as a template. It was adopted as a sensing interface to construct an electrochemical bacteria immunosensor for the rapid detection of foodborne pathogens Escherichia coli ( E. coli) O157:H7. Bacterial antibody was immobilized onto the surface of Ag nanoflowers through covalent conjugation. Electrochemical impedance spectroscopy (EIS) was used to detect and validate the resistance changes, where [Fe(CN)6]3-/4- acted as the redox probe. A linear relation between R et and E. coli concentration was obtained in the E. coli concentration range of 3.0 × 102-3.0 × 108 cfu mL-1. The as-prepared biosensor gave rise to an obvious response to E. coli but had no distinct response to Cronobacter sakazakii, methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus albus, Lactobacillus easei, and Shigella flexneri, revealing a high selectivity for the detection of the pathogens down to 100 cfu mL-1 in a short time. We believe that this BSA-conjugated 3D Ag nanoflowers could be used as a powerful interface material with good conductivity and biocompatibility for improving pathogen detection and treatment in the field of medicine, environment, and food safety.

Programmed Pathogen Sense and Destroy Circuits

DTIC Science & Technology

2009-02-18

detection and the peptide-mediated Com QS system of Bacillus subtilis for gram-positive detection. Together these two prototype sentinel circuits cover a...and E. coli. We are currently in the process of constructing receivers for a gram-positive pathogen, Bacillus subtilis . Gram-negative...QS signals. Figure 11: Gram positive QS systems. Agr QS of Staphylococcus aureus (left) and Com QS of Bacillus subtilis . Following the successful

Prevalence of the Antibiotic Resistance Genes in Coagulase-Positive-and Negative-Staphylococcus in Chicken Meat Retailed to Consumers

PubMed Central

Osman, Kamelia; Badr, Jihan; Al-Maary, Khalid S.; Moussa, Ihab M. I.; Hessain, Ashgan M.; Girah, Zeinab M. S. Amin; Abo-shama, Usama H.; Orabi, Ahmed; Saad, Aalaa

2016-01-01

The use of antibiotics in farm management (growing crops and raising animals) has become a major area of concern. Its implications is the consequent emergence of antibiotic resistant bacteria (ARB) and accordingly their access into the human food chain with passage of antibiotic resistance genes (ARG) to the normal human intestinal microbiota and hence to other pathogenic bacteria causative human disease. Therefore, we pursued in this study to unravel the frequency and the quinolone resistance determining region, mecA and cfr genes of methicillin-susceptible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA), methicillin-resistant coagulase-negative staphylococci (MRCNS) and methicillin-susceptible coagulase-negative staphylococci (MSCNS) isolated from the retail trade of ready-to-eat raw chicken meat samples collected during 1 year and sold across the Great Cairo area. The 50 Staphylococcus isolated from retail raw chicken meat were analyzed for their antibiotic resistance phenotypic profile on 12 antibiotics (penicillin, oxacillin, methicillin, ampicillin-sulbactam, erythromycin, tetracycline, clindamycin, gentamicin, ciprofloxacin, chloramphenicol, sulfamethoxazole-trimethoprim, and vancomycin) and their endorsement of the quinolone resistance determining region, mecA and cfr genes. The isolation results revealed 50 isolates, CPS (14) and CNS (36), representing ten species (S. aureus, S. hyicus, S. epidermedius, S. lugdunensis, S. haemolyticus, S. hominus, S. schleiferi, S. cohnii, S. intermedius, and S. lentus). Twenty seven isolates were methicillin-resistant. Out of the characterized 50 staphylococcal isolates, three were MRSA but only 2/3 carried the mecA gene. The ARG that bestows resistance to quinolones, β-lactams, macrolides, lincosamides, and streptogramin B [MLS(B)] in MRSA and MR-CNS were perceived. According to the available literature, the present investigation was a unique endeavor into the identification of the quinolone-resistance-determining-regions, the identification of MRSA and MR-CNS from retail chicken meat in Egypt. In addition, these isolates might indicate the promulgation of methicillin, oxacillin and vancomycin resistance in the community and imply food safety hazards. PMID:27920760

Periorbital Necrotizing Fasciitis Secondary to Candida parapsilosis and Streptococcus pyogenes.

PubMed

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

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

Molecular mechanisms of methicillin resistance in Staphylococcus aureus.

PubMed

Domínguez, M A; Liñares, J; Martín, R

1997-09-01

Methicillin-resistant Staphylococcus aureus (MRSA) strains are among the most common nosocomial pathogens. The most significant mechanism of resistance to methicillin in this-species is the acquisition of a genetic determinant (mecA gene). However, resistance seems to have a more complex molecular basis, since additional chromosomal material is involved in such resistance. Besides, overproduction of penicillinase and/or alterations in the PBPs can contribute to the formation of resistance phenotypes. Genetic and environmental factors leading to MRSA are reviewed.

Staphylococcus aureus synthesizes adenosine to escape host immune responses

PubMed Central

Thammavongsa, Vilasack; Kern, Justin W.; Missiakas, Dominique M.

2009-01-01

Staphylococcus aureus infects hospitalized or healthy individuals and represents the most frequent cause of bacteremia, treatment of which is complicated by the emergence of methicillin-resistant S. aureus. We examined the ability of S. aureus to escape phagocytic clearance in blood and identified adenosine synthase A (AdsA), a cell wall–anchored enzyme that converts adenosine monophosphate to adenosine, as a critical virulence factor. Staphylococcal synthesis of adenosine in blood, escape from phagocytic clearance, and subsequent formation of organ abscesses were all dependent on adsA and could be rescued by an exogenous supply of adenosine. An AdsA homologue was identified in the anthrax pathogen, and adenosine synthesis also enabled escape of Bacillus anthracis from phagocytic clearance. Collectively, these results suggest that staphylococci and other bacterial pathogens exploit the immunomodulatory attributes of adenosine to escape host immune responses. PMID:19808256

Quorum Sensing Inhibitors for Staphylococcus aureus from Italian Medicinal Plants

PubMed Central

Quave, Cassandra L.; Plano, Lisa R.W.; Bennett, Bradley C.

2010-01-01

Morbidity and mortality estimates due to methicillin-resistant Staphylococcus aureus (MRSA) infections continue to rise. Therapeutic options are limited by antibiotic resistance. Anti-pathogenic compounds, which inhibit quorum sensing (QS) pathways, may be a useful alternative to antibiotics. Staphylococcal QS is encoded by the agr locus and is responsible for the production of δ-hemolysin. Quantification of δ-hemolysin found in culture supernatants permits the analysis of agr activity at the translational, rather than transcriptional, level. We employed RP-HPLC techniques to investigate the anti-QS activity of 168 extracts from 104 Italian plants through quantification of δ-hemolysin. Extracts from three medicinal plants (Ballota nigra, Castanea sativa, and Sambucus ebulus) exhibited a dose-dependent response in the production of δ-hemolysin, indicating strong anti-QS activity in a pathogenic MRSA isolate. PMID:20645243

Mannose-binding lectin binds to a range of clinically relevant microorganisms and promotes complement deposition.

PubMed

Neth, O; Jack, D L; Dodds, A W; Holzel, H; Klein, N J; Turner, M W

2000-02-01

Mannose-binding lectin (MBL) is a collagenous serum lectin believed to be of importance in innate immunity. Genetically determined low levels of the protein are known to predispose to infections. In this study the binding of purified MBL to pathogens isolated from immunocompromised children was investigated by flow cytometry. Diverse Candida species, Aspergillus fumigatus, Staphylococcus aureus, and beta-hemolytic group A streptococci exhibited strong binding of MBL, whereas Escherichia coli, Klebsiella species, and Haemophilus influenzae type b were characterized by heterogeneous binding patterns. In contrast, beta-hemolytic group B streptococci, Streptococcus pneumoniae, and Staphylococcus epidermidis showed low levels of binding. Bound MBL was able to promote C4 deposition in a concentration-dependent manner. We conclude that MBL may be of importance in first-line immune defense against several important pathogens.

Sulfide Homeostasis and Nitroxyl Intersect via Formation of Reactive Sulfur Species in Staphylococcus aureus.

PubMed

Peng, Hui; Shen, Jiangchuan; Edmonds, Katherine A; Luebke, Justin L; Hickey, Anne K; Palmer, Lauren D; Chang, Feng-Ming James; Bruce, Kevin A; Kehl-Fie, Thomas E; Skaar, Eric P; Giedroc, David P

2017-01-01

Staphylococcus aureus is a commensal human pathogen and a major cause of nosocomial infections. As gaseous signaling molecules, endogenous hydrogen sulfide (H 2 S) and nitric oxide (NO·) protect S. aureus from antibiotic stress synergistically, which we propose involves the intermediacy of nitroxyl (HNO). Here, we examine the effect of exogenous sulfide and HNO on the transcriptome and the formation of low-molecular-weight (LMW) thiol persulfides of bacillithiol, cysteine, and coenzyme A as representative of reactive sulfur species (RSS) in wild-type and Δ cstR strains of S. aureus . CstR is a per- and polysulfide sensor that controls the expression of a sulfide oxidation and detoxification system. As anticipated, exogenous sulfide induces the cst operon but also indirectly represses much of the CymR regulon which controls cysteine metabolism. A zinc limitation response is also observed, linking sulfide homeostasis to zinc bioavailability. Cellular RSS levels impact the expression of a number of virulence factors, including the exotoxins, particularly apparent in the Δ cstR strain. HNO, like sulfide, induces the cst operon as well as other genes regulated by exogenous sulfide, a finding that is traced to a direct reaction of CstR with HNO and to an endogenous perturbation in cellular RSS, possibly originating from disassembly of Fe-S clusters. More broadly, HNO induces a transcriptomic response to Fe overload, Cu toxicity, and reactive oxygen species and reactive nitrogen species and shares similarity with the sigB regulon. This work reveals an H 2 S/NO· interplay in S. aureus that impacts transition metal homeostasis and virulence gene expression. IMPORTANCE Hydrogen sulfide (H 2 S) is a toxic molecule and a recently described gasotransmitter in vertebrates whose function in bacteria is not well understood. In this work, we describe the transcriptomic response of the major human pathogen Staphylococcus aureus to quantified changes in levels of cellular organic reactive sulfur species, which are effector molecules involved in H 2 S signaling. We show that nitroxyl (HNO), a recently described signaling intermediate proposed to originate from the interplay of H 2 S and nitric oxide, also induces changes in cellular sulfur speciation and transition metal homeostasis, thus linking sulfide homeostasis to an adaptive response to antimicrobial reactive nitrogen species.

Sulfide Homeostasis and Nitroxyl Intersect via Formation of Reactive Sulfur Species in Staphylococcus aureus

PubMed Central

Peng, Hui; Shen, Jiangchuan; Edmonds, Katherine A.; Luebke, Justin L.; Hickey, Anne K.; Palmer, Lauren D.; Chang, Feng-Ming James; Bruce, Kevin A.; Kehl-Fie, Thomas E.; Skaar, Eric P.

2017-01-01

ABSTRACT Staphylococcus aureus is a commensal human pathogen and a major cause of nosocomial infections. As gaseous signaling molecules, endogenous hydrogen sulfide (H2S) and nitric oxide (NO·) protect S. aureus from antibiotic stress synergistically, which we propose involves the intermediacy of nitroxyl (HNO). Here, we examine the effect of exogenous sulfide and HNO on the transcriptome and the formation of low-molecular-weight (LMW) thiol persulfides of bacillithiol, cysteine, and coenzyme A as representative of reactive sulfur species (RSS) in wild-type and ΔcstR strains of S. aureus. CstR is a per- and polysulfide sensor that controls the expression of a sulfide oxidation and detoxification system. As anticipated, exogenous sulfide induces the cst operon but also indirectly represses much of the CymR regulon which controls cysteine metabolism. A zinc limitation response is also observed, linking sulfide homeostasis to zinc bioavailability. Cellular RSS levels impact the expression of a number of virulence factors, including the exotoxins, particularly apparent in the ΔcstR strain. HNO, like sulfide, induces the cst operon as well as other genes regulated by exogenous sulfide, a finding that is traced to a direct reaction of CstR with HNO and to an endogenous perturbation in cellular RSS, possibly originating from disassembly of Fe-S clusters. More broadly, HNO induces a transcriptomic response to Fe overload, Cu toxicity, and reactive oxygen species and reactive nitrogen species and shares similarity with the sigB regulon. This work reveals an H2S/NO· interplay in S. aureus that impacts transition metal homeostasis and virulence gene expression. IMPORTANCE Hydrogen sulfide (H2S) is a toxic molecule and a recently described gasotransmitter in vertebrates whose function in bacteria is not well understood. In this work, we describe the transcriptomic response of the major human pathogen Staphylococcus aureus to quantified changes in levels of cellular organic reactive sulfur species, which are effector molecules involved in H2S signaling. We show that nitroxyl (HNO), a recently described signaling intermediate proposed to originate from the interplay of H2S and nitric oxide, also induces changes in cellular sulfur speciation and transition metal homeostasis, thus linking sulfide homeostasis to an adaptive response to antimicrobial reactive nitrogen species. PMID:28656172

Staphylococcus epidermidis in the human skin microbiome mediates fermentation to inhibit the growth of Propionibacterium acnes: Implications of probiotics in acne vulgaris

PubMed Central

Wang, Yanhan; Kuo, Sherwin; Shu, Muya; Yu, Jinghua; Huang, Stephen; Dai, Ashley; Two, Aimee; Gallo, Richard L.; Huang, Chun-Ming

2014-01-01

Increasing evidence demonstrates that commensal microorganisms in the human skin microbiome help fight pathogens and maintain homeostasis of the microbiome. However, it is unclear how these microorganisms maintain biological balance when one of them overgrows. The overgrowth of Propionibacterium acnes (P. acnes), a commensal skin bacterium, has been associated with the progression of acne vulgaris. Our results demonstrate that skin microorganisms can mediate fermentation of glycerol, which is naturally produced in skin, to enhance their inhibitory effects on P. acnes growth. The skin microorganisms, most of which have been identified as Staphylococcus epidermidis (S. epidermidis), in the microbiome of human fingerprints can ferment glycerol and create inhibition zones to repel a colony of overgrown P. acnes. Succinic acid, one of four short-chain fatty acids (SCFAs) detected in fermented media by nuclear magnetic resonance (NMR) analysis, effectively inhibits the growth of P. acnes in vitro and in vivo. Both intralesional injection and topical application of succinic acid to P. acnes-induced lesions markedly suppress the P. acnes-induced inflammation in mice. We demonstrate for the first time that bacterial members in the skin microbiome can undergo fermentation to rein in the overgrowth of P. acnes. The concept of bacterial interference between P. acnes and S. epidermidis via fermentation can be applied to develop probiotics against acne vulgaris and other skin diseases. In addition, it will open up an entirely new area of study for the biological function of the skin microbiome in promoting human health. PMID:24265031

Flow cytofluorometric assay of human whole blood leukocyte DNA degradation in response to Yersinia pestis and Staphylococcus aureus

NASA Astrophysics Data System (ADS)

Kravtsov, Alexander L.; Grebenyukova, Tatyana P.; Bobyleva, Elena V.; Golovko, Elena M.; Malyukova, Tatyana A.; Lyapin, Mikhail N.; Kostyukova, Tatyana A.; Yezhov, Igor N.; Kuznetsov, Oleg S.

2001-05-01

Human leukocytes containing less than 2C DNA per cell (damaged or dead cells) were detected and quantified by flow cytometry and DNA-specific staining with ethidium bromide and mithramycin in whole blood infected with Staphylococcus aureus or Yersinia pestis. Addition of live S. aureus to the blood (100 microbe cells per one leukocyte) resulted in rapid degradation of leukocyte DNA within 3 to 6 hours of incubation at 37 degree(s)C. However, only about 50 percent cells were damaged and the leukocytes with the intact genetic apparatus could be found in the blood for a period up to 24 hours. The leukocyte injury was preceded by an increase of DNA per cell content (as compared to the normal one) that was likely to be connected with the active phagocytosis of S. aureus by granulocytes (2C DNA of diploid phagocytes plus the all bacterial DNA absorbed). In response to the same dose of actively growing (at 37 degree(s)C) virulent Y. pestis cells, no increase in DNA content per cell could be observed in the human blood leukocytes. The process of the leukocyte DNA degradation started after a 6-hour incubation, and between 18 to 24 hours of incubation about 90 percent leukocytes (phagocytes and lymphocytes) lost their specific DNA fluorescence. These results demonstrated a high potential of flow cytometry in comparative analysis in vitro of the leukocyte DNA degradation process in human blood in response to bacteria with various pathogenic properties. They agree with the modern idea of an apoptotic mechanism of immunosuppression in plague.

The δ Subunit of RNA Polymerase Guides Promoter Selectivity and Virulence in Staphylococcus aureus

PubMed Central

Weiss, Andy; Ibarra, J. Antonio; Paoletti, Jessica; Carroll, Ronan K.

2014-01-01

In Gram-positive bacteria, and particularly the Firmicutes, the DNA-dependent RNA polymerase (RNAP) complex contains an additional subunit, termed the δ factor, or RpoE. This enigmatic protein has been studied for more than 30 years for various organisms, but its function is still not well understood. In this study, we investigated its role in the major human pathogen Staphylococcus aureus. We showed conservation of important structural regions of RpoE in S. aureus and other species and demonstrated binding to core RNAP that is mediated by the β and/or β′ subunits. To identify the impact of the δ subunit on transcription, we performed transcriptome sequencing (RNA-seq) analysis and observed 191 differentially expressed genes in the rpoE mutant. Ontological analysis revealed, quite strikingly, that many of the downregulated genes were known virulence factors, while several mobile genetic elements (SaPI5 and prophage ϕSA3usa) were strongly upregulated. Phenotypically, the rpoE mutant had decreased accumulation and/or activity of a number of key virulence factors, including alpha toxin, secreted proteases, and Panton-Valentine leukocidin (PVL). We further observed significantly decreased survival of the mutant in whole human blood, increased phagocytosis by human leukocytes, and impaired virulence in a murine model of infection. Collectively, our results demonstrate that the δ subunit of RNAP is a critical component of the S. aureus transcription machinery and plays an important role during infection. PMID:24491578

The δ subunit of RNA polymerase guides promoter selectivity and virulence in Staphylococcus aureus.

PubMed

Weiss, Andy; Ibarra, J Antonio; Paoletti, Jessica; Carroll, Ronan K; Shaw, Lindsey N

2014-04-01

In Gram-positive bacteria, and particularly the Firmicutes, the DNA-dependent RNA polymerase (RNAP) complex contains an additional subunit, termed the δ factor, or RpoE. This enigmatic protein has been studied for more than 30 years for various organisms, but its function is still not well understood. In this study, we investigated its role in the major human pathogen Staphylococcus aureus. We showed conservation of important structural regions of RpoE in S. aureus and other species and demonstrated binding to core RNAP that is mediated by the β and/or β' subunits. To identify the impact of the δ subunit on transcription, we performed transcriptome sequencing (RNA-seq) analysis and observed 191 differentially expressed genes in the rpoE mutant. Ontological analysis revealed, quite strikingly, that many of the downregulated genes were known virulence factors, while several mobile genetic elements (SaPI5 and prophage SA3usa) were strongly upregulated. Phenotypically, the rpoE mutant had decreased accumulation and/or activity of a number of key virulence factors, including alpha toxin, secreted proteases, and Panton-Valentine leukocidin (PVL). We further observed significantly decreased survival of the mutant in whole human blood, increased phagocytosis by human leukocytes, and impaired virulence in a murine model of infection. Collectively, our results demonstrate that the δ subunit of RNAP is a critical component of the S. aureus transcription machinery and plays an important role during infection.

Methicillin-resistant Staphylococcus aureus among animals: current overview.

PubMed

Aires-de-Sousa, M

2017-06-01

Currently, methicillin-resistant Staphylococcus aureus (MRSA) is a universal threat. After being well established in the healthcare setting, it has emerged in the community among people with no risk factors for MRSA acquisition, therefore imposing a new threat. The subsequent detection of MRSA colonizing or infecting animals as well as in food of animal origin was of major concern, revealing new reservoirs for MRSA. The major MRSA clonal lineages circulating in the different settings, i.e. in hospitals, in the community and among animals, are described here, differentiating between clones colonizing companion and food-chain animals. Particular attention is given to the widely spread livestock-associated MRSA clonal complex (CC) 398, which is mainly associated with professional exposure but may be of high pathogenicity. The recent detection of a mecA homologue, designated mecC, with a wide geographical distribution in Europe, and including a large diversity of hosts (food-chain, companion and wildlife animals and also detected in water samples) adds to the threat. Domestication as well as globalization of the livestock industry have intensified exchanges between human and animal bacteria. We report here several cases of transmission of MRSA between companion or food-chain animals and humans, as well as some MRSA clones of human origin that have adapted to new animal hosts eventually by losing useless virulence factors or acquiring new mobile genetic elements. Copyright © 2016 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

Changing characteristics of livestock-associated meticillin-resistant Staphylococcus aureus isolated from humans - emergence of a subclade transmitted without livestock exposure, the Netherlands, 2003 to 2014.

PubMed

Bosch, Thijs; van Luit, Martijn; Pluister, Gerlinde N; Frentz, Dineke; Haenen, Anja; Landman, Fabian; Witteveen, Sandra; van Marm-Wattimena, Naomi; van der Heide, Han G; Schouls, Leo M

2016-05-26

Since 2007, livestock-associated meticillin-resistant Staphylococcus aureus (LA-MRSA) has become the predominant MRSA clade isolated from humans in the Netherlands. To assess possible temporal changes, we molecularly characterised over 9,000 LA-MRSA isolates submitted from 2003 to 2014 to the Dutch MRSA surveillance. After an initial rapid increase with a peak in 2009 (n = 1,368), the total number of submitted LA-MRSA isolates has been slowly decreasing to 968 in 2014 and over 80% of LA-MRSA belonged to one of three predominant MLVA/spa-types. Next generation sequencing (n=118) showed that MT569/t034 isolates were genetically more diverse than MT398/t011 and MT572/t108. Concurrent with the decrease in LA-MRSA, fewer people reported having contact with livestock and this was most prominent for people carrying MT569/t034 LA-MRSA. The proportion of LA-MRSA isolated from infection-related materials increased from 6% in 2009, to 13% in 2014 and most of these isolates originated from patients older than 50 years of age. Remarkably, 83% of these patients reported not having contact with livestock. The results reveal an ongoing change in the genotypic and epidemiological characteristics of Dutch LA-MRSA isolated from humans with the emergence of a LA-MRSA subclade independent of livestock exposure, suggesting LA-MRSA starts to resemble non-LA-MRSA in terms of transmissibility and pathogenicity.

Silver nanoparticles: Antimicrobial activity, cytotoxicity, and synergism with N-acetyl cysteine.

PubMed

Hamed, Selwan; Emara, Mohamed; Shawky, Riham M; El-Domany, Ramadan A; Youssef, Tareq

2017-08-01

The fast progression of nanotechnology has led to novel therapeutic interventions. Antimicrobial activities of silver nanoparticles (Ag NPs) were tested against standard ATCC strains of Staphylococcus aureus (ATCC 9144), Escherichia coli (O157:H7), Pseudomonas aeruginosa (ATCC 27853), and Candida albicans (ATCC 90028) in addition to 60 clinical isolates collected from cancer patients. Antimicrobial activity was tested by disk diffusion method and MIC values for Ag NPs alone and in combination with N-acetylcysteine (NAC) against tested pathogens were determined by broth microdilution method. Ag NPs showed a robust antimicrobial activity against all tested pathogens and NAC substantially enhanced the antimicrobial activity of Ag NPs against all tested pathogens. Synergism between Ag NPs and NAC has been confirmed by checkerboard assay. The effect of Ag NPs on tested pathogens was further scrutinized by Transmission Electron Microscope (TEM) which showed disruption of cell wall in both bacteria and fungi. Ag NPs abrogated the activity of respiratory chain dehydrogenase of all tested pathogens and released muramic acid content from S. aureus in culture. The cytotoxic effect of Ag NPs alone and in combination with NAC was examined using human HepG2 cells and this revealed no cytotoxicity at MIC values of Ag NPs and interestingly, NAC reduced the cytotoxic effect of Ag NPs at concentrations higher than their MIC values. Taken together, Ag NPs have robust antimicrobial activity and NAC substantially enhances their antimicrobial activities against MDR pathogens which would provide a novel safe, effective, and inexpensive therapeutic approach to control the prevalence of MDR pathogens. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Invited review: effect, persistence, and virulence of coagulase-negative Staphylococcus species associated with ruminant udder health.

PubMed

Vanderhaeghen, W; Piepers, S; Leroy, F; Van Coillie, E; Haesebrouck, F; De Vliegher, S

2014-09-01

The aim of this review is to assess the effect of coagulase-negative staphylococci (CNS) species on udder health and milk yield in ruminants, and to evaluate the capacity of CNS to cause persistent intramammary infections (IMI). Furthermore, the literature on factors suspected of playing a role in the pathogenicity of IMI-associated CNS, such as biofilm formation and the presence of various putative virulence genes, is discussed. The focus is on the 5 CNS species that have been most frequently identified as causing bovine IMI using reliable molecular identification methods (Staphylococcus chromogenes, Staphylococcus simulans, Staphylococcus haemolyticus, Staphylococcus xylosus, and Staphylococcus epidermidis). Although the effect on somatic cell count and milk production is accepted to be generally limited or nonexistent for CNS as a group, indications are that the typical effects differ between CNS species and perhaps even strains. It has also become clear that many CNS species can cause persistent IMI, contrary to what has long been believed. However, this trait appears to be quite complicated, being partly strain dependent and partly dependent on the host's immunity. Consistent definitions of persistence and more uniform methods for testing this phenomenon will benefit future research. The factors explaining the anticipated differences in pathogenic behavior appear to be more difficult to evaluate. Biofilm formation and the presence of various staphylococcal virulence factors do not seem to (directly) influence the effect of CNS on IMI but the available information is indirect or insufficient to draw consistent conclusions. Future studies on the effect, persistence, and virulence of the different CNS species associated with IMI would benefit from using larger and perhaps even shared strain collections and from adjusting study designs to a common framework, as the large variation currently existing therein is a major problem. Also within-species variation should be investigated. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Effectiveness of a Glycylcycline Antibiotic for Reducing the Pathogenicity of Superantigen-Producing Methicillin-Resistant Staphylococcus aureus in Burn Wounds

PubMed Central

Nosanov, Lauren B.; Jo, Daniel Y.; Randad, Pranay R.; Moffatt, Lauren T.; Carney, Bonnie C.; Ortiz, Rachel T.

2017-01-01

Objective: Burn-injured patients are highly susceptible to infectious complications, which are often associated with increased morbidity and mortality. Rates of antibiotic resistance have increased, and resistant species such as methicillin-resistant Staphylococcus aureus provide additional challenges in the form of virulence factors. Proteins can disrupt local healing, leading to systemic immune disruption. To optimize outcomes, treatments that reduce pathogenicity must be identified. This study aims to compare a glycylcycline antibiotic—tigecycline—with clindamycin for effectiveness in treating superantigenic methicillin-resistant Staphylococcus aureus in burn wounds. Methods: Sprague-Dawley rats received paired 2 × 2-cm burn wounds, which were subsequently inoculated with known virulence factor–producing methicillin-resistant Staphylococcus aureus or media alone on postinjury day 1. Infected animals received twice-daily tigecycline (high or low dose), twice-daily clindamycin (high or low dose), or saline alone (positive controls). Daily sampling and imaging assessments were performed. Results: Bacterial counts and toxin levels were reduced significantly in antibiotic-treated groups relative to positive controls (P < .001). Results from day 7 showed measurable toxin levels in clindamycin-treated, but not tigecycline-treated, wounds. Imaging analysis revealed a return of wound perfusion in tigecycline-treated animals similar to the sham animals. Transcript analysis using polymerase chain reaction and polymerase chain reaction arrays demonstrated downregulation of gene expression in antibiotic-treated animals as compared with positive controls. Conclusions: Overall, this study supports the use of tigecycline in the treatment of methicillin-resistant Staphylococcus aureus–infected burn wounds. While both protein synthesis inhibitors are effective, tigecycline appears to be superior in controlling toxin levels, enabling better wound healing. PMID:28943993

Effectiveness of a Glycylcycline Antibiotic for Reducing the Pathogenicity of Superantigen-Producing Methicillin-Resistant Staphylococcus aureus in Burn Wounds.

PubMed

Nosanov, Lauren B; Jo, Daniel Y; Randad, Pranay R; Moffatt, Lauren T; Carney, Bonnie C; Ortiz, Rachel T; Shupp, Jeffrey W

2017-01-01

Objective : Burn-injured patients are highly susceptible to infectious complications, which are often associated with increased morbidity and mortality. Rates of antibiotic resistance have increased, and resistant species such as methicillin-resistant Staphylococcus aureus provide additional challenges in the form of virulence factors. Proteins can disrupt local healing, leading to systemic immune disruption. To optimize outcomes, treatments that reduce pathogenicity must be identified. This study aims to compare a glycylcycline antibiotic-tigecycline-with clindamycin for effectiveness in treating superantigenic methicillin-resistant Staphylococcus aureus in burn wounds. Methods : Sprague-Dawley rats received paired 2 × 2-cm burn wounds, which were subsequently inoculated with known virulence factor-producing methicillin-resistant Staphylococcus aureus or media alone on postinjury day 1. Infected animals received twice-daily tigecycline (high or low dose), twice-daily clindamycin (high or low dose), or saline alone (positive controls). Daily sampling and imaging assessments were performed. Results : Bacterial counts and toxin levels were reduced significantly in antibiotic-treated groups relative to positive controls ( P < .001). Results from day 7 showed measurable toxin levels in clindamycin-treated, but not tigecycline-treated, wounds. Imaging analysis revealed a return of wound perfusion in tigecycline-treated animals similar to the sham animals. Transcript analysis using polymerase chain reaction and polymerase chain reaction arrays demonstrated downregulation of gene expression in antibiotic-treated animals as compared with positive controls. Conclusions : Overall, this study supports the use of tigecycline in the treatment of methicillin-resistant Staphylococcus aureus -infected burn wounds. While both protein synthesis inhibitors are effective, tigecycline appears to be superior in controlling toxin levels, enabling better wound healing.

Molecular mechanisms of mucocutaneous immunity against Candida and Staphylococci

PubMed Central

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

2013-01-01

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

Indolo[3,2-a]carbazoles from a deep-water sponge of the genus Asteropus.

PubMed

Russell, Floyd; Harmody, Dedra; McCarthy, Peter J; Pomponi, Shirley A; Wright, Amy E

2013-10-25

Two new indolo[3,2-a]carbazoles (1, 2) were isolated from a deep-water collection of a sponge of the genus Asteropus. The structures of 1 and 2 were determined through the analysis of spectroscopic data including mass spectrometry and 2D-NMR. Compound 1 showed minimum inhibitory concentrations of 25 μg/mL against the fungal pathogen Candida albicans and 50 μg/mL against methicillin-resistant Staphylococcus aureus (MRSA). Compounds 1 and 2 showed no cytotoxicity against the PANC1 human pancreatic carcinoma and NCI/ADR-RES ovarian adenocarcinoma cell lines at our standard test concentration of 5 μg/mL.

Indolo[3,2-a]carbazoles from a Deep-Water Sponge of the Genus Asteropus

PubMed Central

2013-01-01

Two new indolo[3,2-a]carbazoles (1, 2) were isolated from a deep-water collection of a sponge of the genus Asteropus. The structures of 1 and 2 were determined through the analysis of spectroscopic data including mass spectrometry and 2D-NMR. Compound 1 showed minimum inhibitory concentrations of 25 μg/mL against the fungal pathogen Candida albicans and 50 μg/mL against methicillin-resistant Staphylococcus aureus (MRSA). Compounds 1 and 2 showed no cytotoxicity against the PANC1 human pancreatic carcinoma and NCI/ADR-RES ovarian adenocarcinoma cell lines at our standard test concentration of 5 μg/mL. PMID:24063539

Antibacterial Activity of Lactic Acid Bacteria Isolated from Gastrointestinal Tract of “Ayam Kampung” Chicken Against Food Pathogens

NASA Astrophysics Data System (ADS)

Nur Jannah, Siti; Rini Saraswati, Tyas; Handayani, Dwi; Pujiyanto, Sri

2018-05-01

Food borne disease results from ingestion of water and wide variety of food contaminated with pathogenic organisms. The main causes of food borne diseases are bacteria, such as Escherichia coli and Staphylococcus aureus. The objective of this study was to determine antimicrobial activity of lactic acid bacteria (LAB) isolated from local chicken gastrointestinal tract with an emphasis on their probiotic properties. The colonies of bacteria that producing clear zone on MRSA plus 0.5% CaCO3, Gram-positive and catalase-negative were isolated as lactic acid bacteria. Some of the strains (10 isolates) were tested for their ability to inhibit growth of Escherichia coli and Staphylococcus aureus, and for acid pH and bile salt tolerance. The results showed that the all selected isolates producing antimicrobial compounds inhibits the growth of Escherichia coli and Staphylococcus aureus, both in the supernatant and supernatant plus 2M NaOH, and still growing in medium condition with pH 2.0 and 0.1% bile salt. It revealing the potential use of the lactic acid bacteria from chicken gastrointestinal tract for probiotics in food.

Differentiation between Staphylococcus aureus and coagulase-negative Staphylococcus species by real-time PCR including detection of methicillin resistants in comparison to conventional microbiology testing.

PubMed

Klaschik, Sven; Lehmann, Lutz E; Steinhagen, Folkert; Book, Malte; Molitor, Ernst; Hoeft, Andreas; Stueber, Frank

2015-03-01

Staphylococcus aureus has long been recognized as a major pathogen. Methicillin-resistant strains of S. aureus (MRSA) and methicillin-resistant strains of S. epidermidis (MRSE) are among the most prevalent multiresistant pathogens worldwide, frequently causing nosocomial and community-acquired infections. In the present pilot study, we tested a polymerase chain reaction (PCR) method to quickly differentiate Staphylococci and identify the mecA gene in a clinical setting. Compared to the conventional microbiology testing the real-time PCR assay had a higher detection rate for both S. aureus and coagulase-negative Staphylococci (CoNS; 55 vs. 32 for S. aureus and 63 vs. 24 for CoNS). Hands-on time preparing DNA, carrying out the PCR, and evaluating results was less than 5 h. The assay is largely automated, easy to adapt, and has been shown to be rapid and reliable. Fast detection and differentiation of S. aureus, CoNS, and the mecA gene by means of this real-time PCR protocol may help expedite therapeutic decision-making and enable earlier adequate antibiotic treatment. © 2014 Wiley Periodicals, Inc.

A Tick Antivirulence Protein Potentiates Antibiotics against Staphylococcus aureus

PubMed Central

Abraham, Nabil M.; Liu, Lei; Jutras, Brandon L.; Murfin, Kristen; Acar, Ali; Yarovinsky, Timur O.; Sutton, Erica; Heisig, Martin; Jacobs-Wagner, Christine

2017-01-01

ABSTRACT New strategies are needed to combat antibiotic resistance, especially against pathogens such as methicillin-resistant Staphylococcus aureus. A tick antifreeze glycoprotein, IAFGP, possesses potent antibiofilm properties against a variety of clinical pathogens, including S. aureus. Synergy between IAFGP, or a peptide (P1) representative of a repeat region of the protein, with different antibiotics was assessed in vitro. Antibiotics that synergized with either IAFPG or P1 were further evaluated in vivo using vertebrate and invertebrate infection models. IAFGP readily enhanced the efficacy of antibiotics against S. aureus. Synergy with daptomycin, an antibiotic used to treat methicillin-resistant S. aureus, was observed in vitro and in vivo using iafgp-transgenic mice and flies. Furthermore, synergy with ciprofloxacin or gentamicin, antibiotics not generally used to treat S. aureus, was also perceived. The combined effect of the antibiotic and IAFGP was associated with improved permeation of the antibiotic into the cell. Our results highlight that synergy of IAFGP with antibiotics traditionally used to treat this pathogen, and enhancement of the potency of antibiotics not commonly used against this microbe, can provide novel alternative therapeutic strategies to combat bacterial infections. PMID:28438938

Semi-quantitative MALDI-TOF for antimicrobial susceptibility testing in Staphylococcus aureus.

PubMed

Maxson, Tucker; Taylor-Howell, Cheryl L; Minogue, Timothy D

2017-01-01

Antibiotic resistant bacterial infections are a significant problem in the healthcare setting, in many cases requiring the rapid administration of appropriate and effective antibiotic therapy. Diagnostic assays capable of quickly and accurately determining the pathogen resistance profile are therefore crucial to initiate or modify care. Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) is a standard method for species identification in many clinical microbiology laboratories and is well positioned to be applied towards antimicrobial susceptibility testing. One recently reported approach utilizes semi-quantitative MALDI-TOF MS for growth rate analysis to provide a resistance profile independent of resistance mechanism. This method was previously successfully applied to Gram-negative pathogens and mycobacteria; here, we evaluated this method with the Gram-positive pathogen Staphylococcus aureus. Specifically, we used 35 strains of S. aureus and four antibiotics to optimize and test the assay, resulting in an overall accuracy rate of 95%. Application of the optimized assay also successfully determined susceptibility from mock blood cultures, allowing both species identification and resistance determination for all four antibiotics within 3 hours of blood culture positivity.

Targeting Staphylococcus aureus Toxins: A Potential form of Anti-Virulence Therapy

PubMed Central

Kong, Cin; Neoh, Hui-min; Nathan, Sheila

2016-01-01

Staphylococcus aureus is an opportunistic pathogen and the leading cause of a wide range of severe clinical infections. The range of diseases reflects the diversity of virulence factors produced by this pathogen. To establish an infection in the host, S. aureus expresses an inclusive set of virulence factors such as toxins, enzymes, adhesins, and other surface proteins that allow the pathogen to survive under extreme conditions and are essential for the bacteria’s ability to spread through tissues. Expression and secretion of this array of toxins and enzymes are tightly controlled by a number of regulatory systems. S. aureus is also notorious for its ability to resist the arsenal of currently available antibiotics and dissemination of various multidrug-resistant S. aureus clones limits therapeutic options for a S. aureus infection. Recently, the development of anti-virulence therapeutics that neutralize S. aureus toxins or block the pathways that regulate toxin production has shown potential in thwarting the bacteria’s acquisition of antibiotic resistance. In this review, we provide insights into the regulation of S. aureus toxin production and potential anti-virulence strategies that target S. aureus toxins. PMID:26999200

Passive therapy with humanized anti-staphylococcal enterotoxin B antibodies attenuates systemic inflammatory response and protects from lethal pneumonia caused by staphylococcal enterotoxin B-producing Staphylococcus aureus.

PubMed

Karau, Melissa J; Tilahun, Mulualem E; Krogman, Ashton; Osborne, Barbara A; Goldsby, Richard A; David, Chella S; Mandrekar, Jayawant N; Patel, Robin; Rajagopalan, Govindarajan

2017-10-03

Drugs such as linezolid that inhibit bacterial protein synthesis may be beneficial in treating infections caused by toxigenic Staphylococcus aureus. As protein synthesis inhibitors have no effect on preformed toxins, neutralization of pathogenic exotoxins with anti-toxin antibodies may be beneficial in conjunction with antibacterial therapy. Herein, we evaluated the efficacy of human-mouse chimeric high-affinity neutralizing anti-staphylococcal enterotoxin B (SEB) antibodies in the treatment of experimental pneumonia caused by SEB-producing S. aureus. Since HLA class II transgenic mice mount a stronger systemic immune response following challenge with SEB and are more susceptible to SEB-induced lethal toxic shock than conventional mice strains, HLA-DR3 transgenic mice were used. Lethal pneumonia caused by SEB-producing S. aureus in HLA-DR3 transgenic mice was characterized by robust T cell activation and elevated systemic levels of several pro-inflammatory cytokines and chemokines. Prophylactic administration of a single dose of linezolid 30 min prior to the onset of infection attenuated the systemic inflammatory response and protected from mortality whereas linezolid administered 60 min after the onset of infection failed to confer significant protection. Human-mouse chimeric high-affinity neutralizing anti-SEB antibodies alone, but not polyclonal human IgG, mitigated this response and protected from death when administered immediately after initiation of infection. Further, anti-SEB antibodies as well as intact polyclonal human IgG, but not its Fab or Fc fragments, protected from lethal pneumonia when followed with linezolid therapy 60 min later. In conclusion, neutralization of superantigens with high-affinity antibodies may have beneficial effects in pneumonia.

Antimicrobial resistance and population structure of Staphylococcus epidermidis recovered from animals and humans.

PubMed

Argudín, M Angeles; Vanderhaeghen, Wannes; Vandendriessche, Stien; Vandecandelaere, Ilse; André, François-Xavier; Denis, Olivier; Coenye, Tom; Butaye, Patrick

2015-07-09

While Staphylococcus epidermidis, as part of the commensal flora, is a well-known human opportunistic pathogen, only little is known about the genetic relatedness of S. epidermidis carriage isolates from animal and human origin. This study aimed to compare S. epidermidis recovered from livestock, livestock-farmers and humans associated with the hospital environment. A total of 193 S. epidermidis isolates from three populations [animals (n=33), farmers (n=86) and hospital-associated (n=74)] were characterized by broth microdilution antimicrobial susceptibility testing, staphylococcal cassette chromosome mec (SCCmec) typing, pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). The overall S. epidermidis nasal colonization rate was low in animals (1-9%) but high among farmers (75%). High levels of multi-resistance were found in all populations. Tetracycline resistance was high in animal and farmer isolates; resistance to erythromycin, clindamycin and trimethoprim was high in animal and hospital-associated isolates. Methicillin-resistant S. epidermidis - MRSE isolates were found in all collections, with 22 (67%) MRSE in animals, 44 (51%) MRSE in farmers and 42 (57%) MRSE associated with the hospital-setting. Known SCCmec types and variants were detected in 79% of MRSE; the rest were non-typeable cassettes. In total 79 PFGE-types were found, of which 22 were shared between livestock, farmers and the hospital settings. Clonal complex 2 was predominant in all three populations and most STs corresponded to types previously observed in community and nosocomial S. epidermidis populations. S. epidermidis isolates from livestock, farmers and hospital-setting showed a high level of diversity, but some clones can be found in humans as well as in animals. Copyright © 2015 Elsevier B.V. All rights reserved.

Bioactivity of Malva Sylvestris L., a Medicinal Plant from Iran

PubMed Central

Razavi, Seyed Mehdi; Zarrini, Gholamreza; Molavi, Ghader; Ghasemi, Ghader

2011-01-01

Objective(s) Malva sylvestris L. (Malvaceae), an annual plant, has been already commonly used as a medicinal plant in Iran. In the present work, we evaluate some bioactivities of the plant extracts. Materials and Methods The aired-dried plant flowers and leaves were extracted by soxhlet apparatus with n-hexane, dichloromethane and methanol. The antimicrobial, cytotoxic, and phytotoxic of the plant extracts were evaluated using disk diffusion method, MTT, and Lettuce assays, respectively. Results Both flowers and leaves of M. sylvestris methanol extracts exhibited strong antibacterial effects against Erwinia carotovora, a plant pathogen, with MIC value of 128 and 256 µg/ml, respectively. The flowers extract also showed high antibacterial effects against some human pathogen bacteria strains such as Staphylococcus aureus, Streptococcus agalactiae, Entrococcus faecalis, with MIC value of 192, 200 and 256 µg/ml, respectively. The plant methanol extracts had relatively high cytotoxic activity against MacCoy cell line. Conclusion We concluded that Malva sylvestris can be candidated as an antiseptic, a chemopreventive or a chemotherapeutic agent. PMID:23493458

Isolation, characterization and chromatography based purification of antibacterial compound isolated from rare endophytic actinomycetes Micrococcus yunnanensis.

PubMed

Ranjan, Ravi; Jadeja, Vasantba

2017-10-01

Endophytic actinomycetes are considered as one of the relatively unexplored potential sources in search of antibiotic producer against antibiotic resistant pathogens. A potent strain isolated from Catharanthus roseus that displays antibacterial potential against antibiotic resistant human pathogen Staphylococcus aureus was characterized and designated as Micrococcus yunnanensis strain rsk5. Rsk5 is capable of producing optimum antibacterial metabolites on starch casein medium at 30 °C, pH 5 and 2% NaCl condition. The crude antibacterial agent was extracted from fermentation broth by ethyl acetate and separated by TLC using chloroform-methanol (24:1, v/v) solvent system with R f value of 0.26. It was partially purified by flash chromatography, followed by HPLC and analyzed by ultraviolet visible spectrophotometer to get absorption maxima at 208.4 nm. The ESI-MS spectra showed molecular ion peaks at m / z 472.4 [M-H], which does not match with any known antibacterial compound.

Systematic Review of the Human Milk Microbiota.

PubMed

Fitzstevens, John L; Smith, Kelsey C; Hagadorn, James I; Caimano, Melissa J; Matson, Adam P; Brownell, Elizabeth A

2017-06-01

Human milk-associated microbes are among the first to colonize the infant gut and may help to shape both short- and long-term infant health outcomes. We performed a systematic review to characterize the microbiota of human milk. Relevant primary studies were identified through a comprehensive search of PubMed (January 1, 1964, to June 31, 2015). Included studies were conducted among healthy mothers, were written in English, identified bacteria in human milk, used culture-independent methods, and reported primary results at the genus level. Twelve studies satisfied inclusion criteria. All varied in geographic location and human milk collection/storage/analytic methods. Streptococcus was identified in human milk samples in 11 studies (91.6%) and Staphylococcus in 10 (83.3%); both were predominant genera in 6 (50%). Eight of the 12 studies used conventional ribosomal RNA (rRNA) polymerase chain reaction (PCR), of which 7 (87.5%) identified Streptococcus and 6 (80%) identified Staphylococcus as present. Of these 8 studies, 2 (25%) identified Streptococcus and Staphylococcus as predominant genera. Four of the 12 studies used next-generation sequencing (NGS), all of which identified Streptococcus and Staphylococcus as present and predominant genera. Relative to conventional rRNA PCR, NGS is a more sensitive method to identify/quantify bacterial genera in human milk, suggesting the predominance of Streptococcus and Staphylococcus may be underestimated in studies using older methods. These genera, Streptococcus and Staphylococcus, may be universally predominant in human milk, regardless of differences in geographic location or analytic methods. Primary studies designed to evaluate the effect of these 2 genera on short- and long-term infant outcomes are warranted.

Bio-Sensing of Cadmium(II) Ions Using Staphylococcus aureus†

PubMed Central

Sochor, Jiri; Zitka, Ondrej; Hynek, David; Jilkova, Eva; Krejcova, Ludmila; Trnkova, Libuse; Adam, Vojtech; Hubalek, Jaromir; Kynicky, Jindrich; Vrba, Radimir; Kizek, Rene

2011-01-01

Cadmium, as a hazardous pollutant commonly present in the living environment, represents an important risk to human health due to its undesirable effects (oxidative stress, changes in activities of many enzymes, interactions with biomolecules including DNA and RNA) and consequent potential risk, making its detection very important. New and unique technological and biotechnological approaches for solving this problems are intensely sought. In this study, we used the commonly occurring potential pathogenic microorganism Staphylococcus aureus for the determination of markers which could be used for sensing of cadmium(II) ions. We were focused on monitoring the effects of different cadmium(II) ion concentrations (0, 1.25, 2.5, 5, 10, 15, 25 and 50 μg mL−1) on the growth and energetic metabolism of Staphylococcus aureus. Highly significant changes have been detected in the metabolism of thiol compounds—specifically the protein metallothionein (0.79–26.82 mmol/mg of protein), the enzyme glutathione S-transferase (190–5,827 μmol/min/mg of protein), and sulfhydryl groups (9.6–274.3 μmol cysteine/mg of protein). The ratio of reduced and oxidized glutathione indicated marked oxidative stress. In addition, dramatic changes in urease activity, which is connected with resistance of bacteria, were determined. Further, the effects of cadmium(II) ions on the metabolic pathways of arginine, β-glucosidase, phosphatase, N-acetyl β-d-glucosamine, sucrose, trehalose, mannitol, maltose, lactose, fructose and total proteins were demonstrated. A metabolomic profile of Staphylococcus aureus under cadmium(II) ion treatment conditions was completed seeking data about the possibility of cadmium(II) ion accumulation in cells. The results demonstrate potential in the application of microorganisms as modern biosensor systems based on biological components. PMID:22346664

A novel hybrid SCCmec-mecC region in Staphylococcus sciuri

PubMed Central

Harrison, Ewan M.; Paterson, Gavin K.; Holden, Matthew T. G.; Ba, Xiaoliang; Rolo, Joana; Morgan, Fiona J. E.; Pichon, Bruno; Kearns, Angela; Zadoks, Ruth N.; Peacock, Sharon J.; Parkhill, Julian; Holmes, Mark A.

2014-01-01

Objectives Methicillin resistance in Staphylococcus spp. results from the expression of an alternative penicillin-binding protein 2a (encoded by mecA) with a low affinity for β-lactam antibiotics. Recently, a novel variant of mecA known as mecC (formerly mecALGA251) was identified in Staphylococcus aureus isolates from both humans and animals. In this study, we identified two Staphylococcus sciuri subsp. carnaticus isolates from bovine infections that harbour three different mecA homologues: mecA, mecA1 and mecC. Methods We subjected the two isolates to whole-genome sequencing to further understand the genetic context of the mec-containing region. We also used PCR and RT–PCR to investigate the excision and expression of the SCCmec element and mec genes, respectively. Results Whole-genome sequencing revealed a novel hybrid SCCmec region at the orfX locus consisting of a class E mec complex (mecI-mecR1-mecC1-blaZ) located immediately downstream of a staphylococcal cassette chromosome mec (SCCmec) type VII element. A second SCCmec attL site (attL2), which was imperfect, was present downstream of the mecC region. PCR analysis of stationary-phase cultures showed that both the SCCmec type VII element and a hybrid SCCmec-mecC element were capable of excision from the genome and forming a circular intermediate. Transcriptional analysis showed that mecC and mecA, but not mecA1, were both expressed in liquid culture supplemented with oxacillin. Conclusions Overall, this study further highlights that a range of staphylococcal species harbour the mecC gene and furthers the view that coagulase-negative staphylococci associated with animals may act as reservoirs of antibiotic resistance genes for more pathogenic staphylococcal species. PMID:24302651

Stethoscopes as potential intrahospital carriers of pathogenic microorganisms.

PubMed

Campos-Murguía, Alejandro; León-Lara, Ximena; Muñoz, Juan M; Macías, Alejandro E; Alvarez, José A

2014-01-01

Stethoscopes can take part in the transmission of health care-associated infections. We cultured 112 stethoscopes by direct imprint on blood agar to estimate the prevalence of potentially pathogenic microorganisms. Forty-eight (47%) produced 50 potentially pathogenic microorganisms; from these, 43 (86%) were Staphylococcus aureus, of which 18 (42%) were methicillin-resistant S. aureus. We concluded that stethoscopes should be considered as potential fomites and must be disinfected routinely before and after each patient contact. Copyright © 2014 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

A potent synthetic inorganic antibiotic with activity against drug-resistant pathogens.

PubMed

Hubick, Shelby; Jayaraman, Arumugam; McKeen, Alexander; Reid, Shelby; Alcorn, Jane; Stavrinides, John; Sterenberg, Brian T

2017-02-06

The acronymously named "ESKAPE" pathogens represent a group of bacteria that continue to pose a serious threat to human health, not only due to their propensity for repeated emergence, but also due to their ability to "eskape" antibiotic treatment. The evolution of multi-drug resistance in these pathogens alone has greatly outpaced the development of new therapeutics, necessitating an alternative strategy for antibiotic development that considers the evolutionary mechanisms driving antibiotic resistance. In this study, we synthesize a novel inorganic antibiotic, phosphopyricin, which has antibiotic activity against the Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VRE). We show that this potent antibiotic is bactericidal, and exhibits low toxicity in an acute dose assay in mice. As a synthetic compound that does not occur naturally, phosphopyricin would be evolutionarily foreign to microbes, thereby slowing the evolution of resistance. In addition, it loses antibiotic activity upon exposure to light, meaning that the active antibiotic will not accumulate in the general environment where strong selective pressures imposed by antibiotic residuals are known to accelerate resistance. Phosphopyricin represents an innovation in antimicrobials, having a synthetic core, and a photosensitive chemical architecture that would reduce accumulation in the environment.

A potent synthetic inorganic antibiotic with activity against drug-resistant pathogens

PubMed Central

Hubick, Shelby; Jayaraman, Arumugam; McKeen, Alexander; Reid, Shelby; Alcorn, Jane; Stavrinides, John; Sterenberg, Brian T.

2017-01-01

The acronymously named “ESKAPE” pathogens represent a group of bacteria that continue to pose a serious threat to human health, not only due to their propensity for repeated emergence, but also due to their ability to “eskape” antibiotic treatment12. The evolution of multi-drug resistance in these pathogens alone has greatly outpaced the development of new therapeutics, necessitating an alternative strategy for antibiotic development that considers the evolutionary mechanisms driving antibiotic resistance. In this study, we synthesize a novel inorganic antibiotic, phosphopyricin, which has antibiotic activity against the Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VRE). We show that this potent antibiotic is bactericidal, and exhibits low toxicity in an acute dose assay in mice. As a synthetic compound that does not occur naturally, phosphopyricin would be evolutionarily foreign to microbes, thereby slowing the evolution of resistance. In addition, it loses antibiotic activity upon exposure to light, meaning that the active antibiotic will not accumulate in the general environment where strong selective pressures imposed by antibiotic residuals are known to accelerate resistance. Phosphopyricin represents an innovation in antimicrobials, having a synthetic core, and a photosensitive chemical architecture that would reduce accumulation in the environment. PMID:28165020

Effects of Lactobacillus rhamnosus and Lactobacillus acidophilus on bacterial vaginal pathogens.

PubMed

Bertuccini, Lucia; Russo, Rosario; Iosi, Francesca; Superti, Fabiana

2017-06-01

The human vagina is colonized by a variety of microbes. Lactobacilli are the most common, mainly in healthy women; however, the microbiota composition can change rapidly, leading to infection or to a state in which potential pathogenic microorganisms co-exist with other commensals. In premenopausal women, urogenital infections, such as bacterial vaginosis and aerobic vaginitis, remain an important health problem. Treatment of these infections involves different kind of antibiotics; however, the recurrence rate remains high, and it must be also underlined that antibiotics are unable to spontaneously restore normal flora characterized by an abundant community of Lactobacilli. The main limitation is the inability to offer a long-term defensive barrier, thus facilitating relapses and recurrences. We report here the antimicrobial activities of two commercially existing Lactobacillus strains, Lactobacillus rhamnosus HN001 and Lactobacillus acidophilus GLA-14 strains and their combination (Respecta® probiotic blend) against four different pathogens responsible for both bacterial vaginosis ( Gardenerella vaginalis and Atopobium vaginae) and aerobic vaginitis ( Staphylococcus aureus and Escherichia coli) by co-culturing assay. The probiotic combination, even if resulting in a different microbicidal activity against the different strains tested, demonstrated the efficacy of combined Lactobacillus strain treatment.

Effects of Lactobacillus rhamnosus and Lactobacillus acidophilus on bacterial vaginal pathogens

PubMed Central

Bertuccini, Lucia; Russo, Rosario; Iosi, Francesca; Superti, Fabiana

2017-01-01

The human vagina is colonized by a variety of microbes. Lactobacilli are the most common, mainly in healthy women; however, the microbiota composition can change rapidly, leading to infection or to a state in which potential pathogenic microorganisms co-exist with other commensals. In premenopausal women, urogenital infections, such as bacterial vaginosis and aerobic vaginitis, remain an important health problem. Treatment of these infections involves different kind of antibiotics; however, the recurrence rate remains high, and it must be also underlined that antibiotics are unable to spontaneously restore normal flora characterized by an abundant community of Lactobacilli. The main limitation is the inability to offer a long-term defensive barrier, thus facilitating relapses and recurrences. We report here the antimicrobial activities of two commercially existing Lactobacillus strains, Lactobacillus rhamnosus HN001 and Lactobacillus acidophilus GLA-14 strains and their combination (Respecta® probiotic blend) against four different pathogens responsible for both bacterial vaginosis (Gardenerella vaginalis and Atopobium vaginae) and aerobic vaginitis (Staphylococcus aureus and Escherichia coli) by co-culturing assay. The probiotic combination, even if resulting in a different microbicidal activity against the different strains tested, demonstrated the efficacy of combined Lactobacillus strain treatment. PMID:28580872

Diversity, evolution and medical applications of insect antimicrobial peptides

PubMed Central

Mylonakis, Eleftherios; Podsiadlowski, Lars; Muhammed, Maged

2016-01-01

Antimicrobial peptides (AMPs) are short proteins with antimicrobial activity. A large portion of known AMPs originate from insects, and the number and diversity of these molecules in different species varies considerably. Insect AMPs represent a potential source of alternative antibiotics to address the limitation of current antibiotics, which has been caused by the emergence and spread of multidrug-resistant pathogens. To get more insight into AMPs, we investigated the diversity and evolution of insect AMPs by mapping their phylogenetic distribution, allowing us to predict the evolutionary origins of selected AMP families and to identify evolutionarily conserved and taxon-specific families. Furthermore, we highlight the use of the nematode Caenorhabditis elegans as a whole-animal model in high-throughput screening methods to identify AMPs with efficacy against human pathogens, including Acinetobacter baumanii and methicillin-resistant Staphylococcus aureus. We also discuss the potential medical applications of AMPs, including their use as alternatives for conventional antibiotics in ectopic therapies, their combined use with antibiotics to restore the susceptibility of multidrug-resistant pathogens, and their use as templates for the rational design of peptidomimetic drugs that overcome the disadvantages of therapeutic peptides. The article is part of the themed issue ‘Evolutionary ecology of arthropod antimicrobial peptides’. PMID:27160593

Hiding in Fresh Fruits and Vegetables: Opportunistic Pathogens May Cross Geographical Barriers

PubMed Central

Al-Kharousi, Zahra S.; Al-Sadi, Abdullah M.; Al-Bulushi, Ismail M.; Shaharoona, Baby

2016-01-01

Different microbial groups of the microbiome of fresh produce can have diverse effects on human health. This study was aimed at identifying some microbial communities of fresh produce by analyzing 105 samples of imported fresh fruits and vegetables originated from different countries in the world including local samples (Oman) for aerobic plate count and the counts of Enterobacteriaceae, Enterococcus, and Staphylococcus aureus. The isolated bacteria were identified by molecular (PCR) and biochemical methods (VITEK 2). Enterobacteriaceae occurred in 60% of fruits and 91% of vegetables. Enterococcus was isolated from 20% of fruits and 42% of vegetables. E. coli and S. aureus were isolated from 22% and 7% of vegetables, respectively. Ninety-seven bacteria comprising 21 species were similarly identified by VITEK 2 and PCR to species level. E. coli, Klebsiella pneumoniae, Enterococcus casseliflavus, and Enterobacter cloacae were the most abundant species; many are known as opportunistic pathogens which may raise concern to improve the microbial quality of fresh produce. Phylogenetic trees showed no relationship between clustering of the isolates based on the 16S rRNA gene and the original countries of fresh produce. Intercountry passage of opportunistic pathogens in fresh produce cannot be ruled out, which requires better management. PMID:26989419

Tailoring shape and size of biogenic silver nanoparticles to enhance antimicrobial efficacy against MDR bacteria.

PubMed

Kumari, Madhuree; Pandey, Shipra; Giri, Ved Prakash; Bhattacharya, Arpita; Shukla, Richa; Mishra, Aradhana; Nautiyal, C S

2017-04-01

Spherical, rectangular, penta, and hexagonal silver nanoparticles of different dimensions were biosynthesized in an eco-friendly manner by biocontrol agent, Trichoderma viride by manipulating physical parameters, pH, temperature, and reaction time. The particles were characterized by UV-vis spectroscopy; Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM) and Fourier Transform Infra-red Spectroscopy (FTIR). Shape and size dependent antimicrobial activity of nanoparticles against human pathogens was observed. Maximum inhibition was found with spherical nanoparticles (2-5 nm) showing 40, 51, 43, 53.9 and 55.8% against Shigella sonnei, Escherichia coli, Serratia marcescens, Staphylococcus. aureus and Pseudomonas aeruginosa respectively, where as pentagonal and hexagonal nanoparticles (50-100 nm) demonstrated 32, 41, 31, 42.84 and 42.80% of inhibition as compared to control. Nanoparticles of different geometry and dimension established enhanced antagonistic activity against pathogens with all the tested antibiotics. Excellent antimicrobial efficacy was obtained with spherical nanoparticles of 2-5 nm with ampicillin and penicillin. Shape and size played major role in enhancing antimicrobial potential of silver nanoparticles, both singly and synergistically with antibiotics which can be exploited to combat the spread of multidrug resistant pathogens. Copyright © 2016. Published by Elsevier Ltd.