Project description:USA300 Staphylococcus aureus is responsible for the current outbreak of skin abscesses in the United States. Unlike other USA types, USA300 colonizes the rectum at rates higher than the nose. The reason for the difference in colonization site preference may be related to specific adherence or attachment factors contained in the genome of these strains. Additional knowledge in this field may help design novel prophylactic and therapeutic strategies to combat staphylococcal infections. Strains of USA300 MSSA and MRSA colonizing the nose and/or rectum from children with staphylococcal skin abscesses were compared by whole genome array technology to identify bacterial genetic determinants associated with site-specific colonization. Strains isolated from different colonization sites were indistinguishable by genomic content. Site-specific colonization traits were not detected in the colonizing bacteria by this array. Either host characteristics associated with staphylococcal carriage or under represented bacterial genomic constructions need to be examined to determine the etiology of this site-specific colonization. Data is also available from <ahref=http://bugs.sgul.ac.uk/E-BUGS-102 target=_blank>BuG@Sbase</a>
Project description:Staphylococcus aureus is a Gram-positive human pathogen causing a variety of human diseases in both hospital and community settings. This bacterium is so closely associated with prophages that it is rare to find S. aureus isolates without prophages. Two phages are known to be important for staphylococcal virulence: the beta-hemolysin (hlb) converting phage and the Panton-Valentine Leukocidin (PVL) converting phage. The hlb-converting phage is found in more than 90% of clinical isolates of S. aureus. This phage produces exotoxins and immune modulatory molecules, which inhibit human innate immune responses. The PVL-converting phage produces the two-component exotoxin PVL, which can kill human leucocytes. This phage is wide-spread among community-associated methicillin resistant S. aureus (CA-MRSA). It also shows strong association with soft tissue infections and necrotizing pneumonia. Several lines of evidence suggest that staphylococcal prophages increase bacterial virulence not only by providing virulence factors but also by altering bacterial gene expression: 1) Transposon insertion into prophage regulatory genes, but not into the genes of virulence factors, reduced S. aureus killing of Caenorhabditis elegans.; 2) Although the toxins and immune modulatory molecules encoded by the hlb- converting phages do not function in the murine system, deletion of NM3, the hlb-converting phage in S. aureus Newman, reduced staphylococcal virulence in the murine abscess formation model. 3) In a preliminary microarray experiment, prophages in S. aureus Newman altered the expression of more than 300 genes. In this research proposal, using microarray and high-throughput quantitative RT-PCR (qRT-PCR) technologies, we will identify the effects of the two important staphylococcal phages on the gene expression of S. aureus in both in vitro and in vivo conditions. This project is intended to be completed within one year. All the data – microarray, qRT-PCR and all the primer sequences- will be made available to public 6 month after completion. Data from this project will help us to understand the role of prophages in the S. aureus pathogenesis and can lead to development of a strategy to interfere with the pathogenesis process. Staphylococcus aureus subsp.aureus strain Newman (reference) and Staphylococcus aureus subsp.aureus strain Newman yhcR knockout(query) were grown in TSA broth.Samples were grown under aerobic and anaerobic conditions and RNA samples harvested at mid log, stationary, and log phases.Samples were hybridized on aminosilane coated slides with 70-mer oligos.
Project description:Old yellow enzymes (OYEs) are widely found in the bacterial, fungal, and plant kingdoms but absent in humans and have been used as biocatalysts for decades. However, OYEs physiological function in bacterial stress response and infection situations remained enigmatic. In the mode of pathogen, the gram-positive bacterium Staphylococcus aureus adapts to numerous stress conditions during pathogenesis. Here we show that in S. aureus genome, two paralogous genes (ofrA and ofrB) encode for two OYEs. We conducted bioinformatic analysis and found that ofrA is conserved among all publicly available representative staphylococcal genomes and some Firmicutes. Expression of ofrA is induced by electrophilic, oxidative, and hypochlorite stress in S. aureus. Furthermore, ofrA contributes to S. aureus survival against reactive electrophilic, oxygen, and chlorine species (RES, ROS, RCS) via thiol-dependent redox homeostasis. At the host-pathogen interface, ofrA mutation affects S. aureus survival in macrophages and whole human blood and the virulence factor staphyloxanthin production. Overall, our results shed the light onto a novel stress response strategy in the bacterial kingdom especially in the important human pathogen S. aureus.
Project description:Staphylococcus aureus is a Gram-positive human pathogen causing a variety of human diseases in both hospital and community settings. This bacterium is so closely associated with prophages that it is rare to find S. aureus isolates without prophages. Two phages are known to be important for staphylococcal virulence: the beta-hemolysin (hlb) converting phage and the Panton-Valentine Leukocidin (PVL) converting phage. The hlb-converting phage is found in more than 90% of clinical isolates of S. aureus. This phage produces exotoxins and immune modulatory molecules, which inhibit human innate immune responses. The PVL-converting phage produces the two-component exotoxin PVL, which can kill human leucocytes. This phage is wide-spread among community-associated methicillin resistant S. aureus (CA-MRSA). It also shows strong association with soft tissue infections and necrotizing pneumonia. Several lines of evidence suggest that staphylococcal prophages increase bacterial virulence not only by providing virulence factors but also by altering bacterial gene expression: 1) Transposon insertion into prophage regulatory genes, but not into the genes of virulence factors, reduced S. aureus killing of Caenorhabditis elegans.; 2) Although the toxins and immune modulatory molecules encoded by the hlb- converting phages do not function in the murine system, deletion of ϕNM3, the hlb-converting phage in S. aureus Newman, reduced staphylococcal virulence in the murine abscess formation model. 3) In a preliminary microarray experiment, prophages in S. aureus Newman altered the expression of more than 300 genes. In this research proposal, using microarray and high-throughput quantitative RT-PCR (qRT-PCR) technologies, we will identify the effects of the two important staphylococcal phages on the gene expression of S. aureus in both in vitro and in vivo conditions. This project is intended to be completed within one year. All the data – microarray, qRT-PCR and all the primer sequences- will be made available to public 6 month after completion. Data from this project will help us to understand the role of prophages in the S. aureus pathogenesis and can lead to development of a strategy to interfere with the pathogenesis process.
Project description:Staphylococcus aureus is a Gram-positive human pathogen causing a variety of human diseases in both hospital and community settings. This bacterium is so closely associated with prophages that it is rare to find S. aureus isolates without prophages. Two phages are known to be important for staphylococcal virulence: the beta-hemolysin (hlb) converting phage and the Panton-Valentine Leukocidin (PVL) converting phage. The hlb-converting phage is found in more than 90% of clinical isolates of S. aureus. This phage produces exotoxins and immune modulatory molecules, which inhibit human innate immune responses. The PVL-converting phage produces the two-component exotoxin PVL, which can kill human leucocytes. This phage is wide-spread among community-associated methicillin resistant S. aureus (CA-MRSA). It also shows strong association with soft tissue infections and necrotizing pneumonia. Several lines of evidence suggest that staphylococcal prophages increase bacterial virulence not only by providing virulence factors but also by altering bacterial gene expression: 1) Transposon insertion into prophage regulatory genes, but not into the genes of virulence factors, reduced S. aureus killing of Caenorhabditis elegans.; 2) Although the toxins and immune modulatory molecules encoded by the hlb- converting phages do not function in the murine system, deletion of ϕNM3, the hlb-converting phage in S. aureus Newman, reduced staphylococcal virulence in the murine abscess formation model. 3) In a preliminary microarray experiment, prophages in S. aureus Newman altered the expression of more than 300 genes. In this research proposal, using microarray and high-throughput quantitative RT-PCR (qRT-PCR) technologies, we will identify the effects of the two important staphylococcal phages on the gene expression of S. aureus in both in vitro and in vivo conditions. This project is intended to be completed within one year. All the data – microarray, qRT-PCR and all the primer sequences- will be made available to public 6 month after completion. Data from this project will help us to understand the role of prophages in the S. aureus pathogenesis and can lead to development of a strategy to interfere with the pathogenesis process. Following strains were grown in TSA broth: Staphylococcus aureus USA300 (reference) Staphylococcus aureus USA300 with deletion of ϕSa2usa (Query) Staphylococcus aureus USA300 with deletion of ϕSa3usa (Query) Staphylococcus aureus USA300 Prophage-free mutant (Query) Staphylococcus aureus USA300 Prophage-free mutant lysogenized with ϕSa2mw (Query) Staphylococcus aureus USA300 Prophage-free mutant lysogenized with ϕSa3usa (Query) strain: Staphylococcus aureus USA300 Prophage-free mutant lysogenized with both ϕSa2mw and ϕSa3usa (Query) RNA samples were harvested at early log, midlog and stationary phase.Samples were hybridized on aminosilane coated slides with 70-mer oligos.
Project description:Staphylococcus aureus is a Gram-positive human pathogen causing a variety of human diseases in both hospital and community settings. This bacterium is so closely associated with prophages that it is rare to find S. aureus isolates without prophages. Two phages are known to be important for staphylococcal virulence: the beta-hemolysin (hlb) converting phage and the Panton-Valentine Leukocidin (PVL) converting phage. The hlb-converting phage is found in more than 90% of clinical isolates of S. aureus. This phage produces exotoxins and immune modulatory molecules, which inhibit human innate immune responses. The PVL-converting phage produces the two-component exotoxin PVL, which can kill human leucocytes. This phage is wide-spread among community-associated methicillin resistant S. aureus (CA-MRSA). It also shows strong association with soft tissue infections and necrotizing pneumonia. Several lines of evidence suggest that staphylococcal prophages increase bacterial virulence not only by providing virulence factors but also by altering bacterial gene expression: 1) Transposon insertion into prophage regulatory genes, but not into the genes of virulence factors, reduced S. aureus killing of Caenorhabditis elegans.; 2) Although the toxins and immune modulatory molecules encoded by the hlb- converting phages do not function in the murine system, deletion of NM3, the hlb-converting phage in S. aureus Newman, reduced staphylococcal virulence in the murine abscess formation model. 3) In a preliminary microarray experiment, prophages in S. aureus Newman altered the expression of more than 300 genes. In this research proposal, using microarray and high-throughput quantitative RT-PCR (qRT-PCR) technologies, we will identify the effects of the two important staphylococcal phages on the gene expression of S. aureus in both in vitro and in vivo conditions. This project is intended to be completed within one year. All the data – microarray, qRT-PCR and all the primer sequences- will be made available to public 6 month after completion. Data from this project will help us to understand the role of prophages in the S. aureus pathogenesis and can lead to development of a strategy to interfere with the pathogenesis process.
Project description:Staphylococcus aureus is a Gram-positive human pathogen causing a variety of human diseases in both hospital and community settings. This bacterium is so closely associated with prophages that it is rare to find S. aureus isolates without prophages. Two phages are known to be important for staphylococcal virulence: the beta-hemolysin (hlb) converting phage and the Panton-Valentine Leukocidin (PVL) converting phage. The hlb-converting phage is found in more than 90% of clinical isolates of S. aureus. This phage produces exotoxins and immune modulatory molecules, which inhibit human innate immune responses. The PVL-converting phage produces the two-component exotoxin PVL, which can kill human leucocytes. This phage is wide-spread among community-associated methicillin resistant S. aureus (CA-MRSA). It also shows strong association with soft tissue infections and necrotizing pneumonia. Several lines of evidence suggest that staphylococcal prophages increase bacterial virulence not only by providing virulence factors but also by altering bacterial gene expression: 1) Transposon insertion into prophage regulatory genes, but not into the genes of virulence factors, reduced S. aureus killing of Caenorhabditis elegans.; 2) Although the toxins and immune modulatory molecules encoded by the hlb- converting phages do not function in the murine system, deletion of phiNM3, the hlb-converting phage in S. aureus Newman, reduced staphylococcal virulence in the murine abscess formation model. 3) In a preliminary microarray experiment, prophages in S. aureus Newman altered the expression of more than 300 genes. In this research proposal, using microarray and high-throughput quantitative RT-PCR (qRT-PCR) technologies, we will identify the effects of the two important staphylococcal phages on the gene expression of S. aureus in both in vitro and in vivo conditions. This project is intended to be completed within one year. All the data – microarray, qRT-PCR and all the primer sequences- will be made available to public 6 month after completion. Data from this project will help us to understand the role of prophages in the S. aureus pathogenesis and can lead to development of a strategy to interfere with the pathogenesis process.
Project description:The custom-made S. epidermidis GeneChips(Shanghai Biochip Co., Ltd) included qualifiers representing open reading frame (ORF) sequences identified in the genomes of the S. epidermidis strain RP62A, as well as unique ORFs in S. epidermidis strain 12228. The GeneChips were composed of cDNA array containing PCR products of 2316 genes and oligonucleotide array containing 252 genes.Two-component regulatory systems (TCSs) play a pivotal role in bacterial adaptation, survival, and virulence by sensing changes in the external environment and modulating gene expression in response to a variety of stimuli.To investigate the regulatory role of LytSR, one of the TCSs identified in the genomes of S. epidermidis, we used the GeneChips to perform a transcriptional profile analysis of the wild strain and lytSR mutant.
Project description:The custom-made S. epidermidis GeneChips(Shanghai Biochip Co., Ltd) included qualifiers representing open reading frame (ORF) sequences identified in the genomes of the S. epidermidis strain RP62A, as well as unique ORFs in S. epidermidis strain 12228. The GeneChips were composed of cDNA array containing PCR products of 2316 genes and oligonucleotide array containing 252 genes.Two-component regulatory systems (TCSs) play a pivotal role in bacterial adaptation, survival, and virulence by sensing changes in the external environment and modulating gene expression in response to a variety of stimuli.To investigate the regulatory role of LytSR, one of the TCSs identified in the genomes of S. epidermidis, we used the GeneChips to perform a transcriptional profile analysis of the wild strain and lytSR mutant. Wild type untreated in triplicate is compared to lytSR mutant in triplicate for cDNA array and four replicates on the oligo array.
Project description:Staphylococcus aureus is the principal causative agent of osteomyelitis, a serious bacterial infection of bone that is associated with progressive inflammatory damage. Bone-forming osteoblasts have increasingly been recognized to play an important role in the initiation and progression of detrimental inflammation at sites of infection, and have been demonstrated to release an array of inflammatory mediators and factors that promote osteoclastogenesis and leukocyte recruitment following bacterial challenge. In the present study, we describe elevated bone tissue levels of the potent neutrophil-attracting chemokines, CXCL1, CXCL2, CXCL3, CXCL5, CCL3, and CCL7, in a murine model of post-traumatic staphylococcal osteomyelitis. RNA-Seq gene ontology analysis of isolated primary murine osteoblasts showed enrichment in differentially expressed genes involved in cell migration and chemokine receptor binding and chemokine activity following S. aureus infection, and a rapid increase in the expression of mRNA encoding CXCL1, CXCL2, CXCL3, CXCL5, CCL3, and CCL7, in these cells. Importantly, we have confirmed that such upregulated gene expression results in protein production with the demonstration that S. aureus challenge elicits the rapid and robust release of these chemokines by osteoblasts and does so in a bacterial dose-dependent manner. Furthermore, we have confirmed the ability of soluble osteoblast-derived chemoattractants to elicit the migration of a neutrophil-like cell line. As such, these studies demonstrate the robust production of CXCL1, CXCL2, CXCL3, CXCL5, CCL3, and CCL7, by osteoblasts in response to S. aureus infection, and the release of such neutrophil-attracting chemokines provides an additional mechanism by which osteoblasts could drive the inflammatory bone loss associated with staphylococcal osteomyelitis.