Staphylococcus aureus subsp. aureus USA300
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ABSTRACT:
PROVIDER: PRJNA171298 | ENA |
REPOSITORIES: ENA
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Project description:Daptomycin is a lipopeptide antibiotic that has recently been approved for treatment of Gram-positive bacterial infections. The mode of action of daptomycin is not yet entirely clear. To further understand the mechanism transcriptomic analysis of changes in gene expression in daptomycin-treated Staphylococcus aureus was carried out. The expression profile indicated that cell wall stress stimulon member genes (B. J. Wilkinson, A. Muthaiyan, and R. K. Jayaswal. 2005. Curr. Med. Chem. Anti-Infective Agents 4: 259-276) were significantly induced by daptomycin, and by the cell wall-active antibiotics vancomycin and oxacillin. Comparison of the daptomycin response of a two-component cell wall stress stimulon regulator VraSR mutant, S. aureus KVR, to its parent N315 showed diminished expression of the cell wall stress stimulon in the mutant. Daptomycin has been proposed to cause membrane depolarization, and the transcriptional responses to carbonyl cyanide m-chlorophenylhydrazone (CCCP) and nisin were determined. Transcriptional profiles of the responses to these antimicrobial agents showed significantly different patterns compared to those of the cell wall-active antibiotics, including little or no induction of the cell wall stress stimulon. However, there were a significant number of genes induced by both CCCP and daptomycin that were not induced by oxacillin or vancomycin, such that the daptomycin transcriptome was probably reflecting a membrane depolarizing activity of this antimicrobial also. The results indicate that inhibition of peptidoglycan biosynthesis, either directly or indirectly, and membrane depolarization are parts of the mode of action of daptomycin. Keywords: mode of action, transcriptional profiling
2007-12-25 | GSE9494 | GEO
Project description:A gene encoding a putative DNA helicase from Staphylococcus aureus USA300 was cloned and expressed in Escherichia coli. The protein was purified to over 90% purity by chromatography. The purified enzyme, SauUSI, predominantly cleaves modified DNA containing 5mC and 5-hydroxymethylcytosine. Cleavage of 5mC-modified plasmids indicated that the sites S5mCNGS (S = C or G) are preferentially digested. The endonuclease activity requires the presence of adenosine triphosphate (ATP) or dATP whereas the non-hydrolyzable γ-S-ATP does not support activity. SauUSI activity was inhibited by ethylenediaminetetraacetic acid. It is most active in Mg(++) buffers. No companion methylase gene was found near the SauUSI restriction gene. The absence of a cognate methylase and cleavage of modified DNA indicate that SauUSI belongs to type IV restriction endonucleases, a group that includes EcoK McrBC and Mrr. SauUSI belongs to a family of highly similar homologs found in other sequenced S. aureus, S. epidermidis and S. carnosus genomes. More distant SauUSI orthologs can be found in over 150 sequenced bacterial/archaea genomes. Finally, we demonstrated the biological function of the type IV REase in restricting 5mC-modified plasmid DNA by transformation into clinical S. aureus strain SA564, and in restricting phage λ infection when the endonuclease is expressed in E. coli.
| S-EPMC3141236 | biostudies-literature
Project description:Expression analysis of Staphylococcus aureus USA300 LAC in response to vehicle and benzbromarone.
| PRJNA241506 | ENA
Project description:The translation inhibitor Linezolid is an important antibiotic of last resort against multiresistant gram-positive pathogens including MRSA. Linezolid is reported to specifically inhibit extracellular virulence factors, but the molecular cause is unknown. To elucidate the physiological response of S. aureus to Linezolid in general and the possible inhibition of virulence factors specifically we performed a holistic study. We added Linezolid to logarithmically growing S. aureus cells and analyzed the Linezolid stress response with transcriptomics, quantitative proteomics and microscopy experiments. As previously observed in studies on other translation inhibitors S. aureus is adapting its protein biosynthesis machinery to the reduced translation efficiency, for example the synthesis of ribosomal proteins is induced. But we also observed unexpected results like a general decline in the amount of extracellular and membrane proteins. In addition cell shape and size changed after Linezolid stress and cell division was diminished. Finally, the chromosome condensed after LZD stress and lost contact to the membrane.
2016-02-22 | GSE65209 | GEO
Project description:The translation inhibitor Linezolid is an important antibiotic of last resort against multiresistant gram-positive pathogens including MRSA. Linezolid is reported to specifically inhibit extracellular virulence factors, but the molecular cause is unknown. To elucidate the physiological response of S. aureus to Linezolid in general and the possible inhibition of virulence factors specifically we performed a holistic study. We added Linezolid to logarithmically growing S. aureus cells and analyzed the Linezolid stress response with transcriptomics, quantitative proteomics and microscopy experiments. As previously observed in studies on other translation inhibitors S. aureus is adapting its protein biosynthesis machinery to the reduced translation efficiency, for example the synthesis of ribosomal proteins is induced. But we also observed unexpected results like a general decline in the amount of extracellular and membrane proteins. In addition cell shape and size changed after Linezolid stress and cell division was diminished. Finally, the chromosome condensed after LZD stress and lost contact to the membrane. sample versus pool design (pool = mixture of equal amounts of all RNA samples analyzed), all RNA samples were isolated as biological triplicates
2016-02-22 | E-GEOD-65209 | biostudies-arrayexpress
Project description:In the United States, methicillin-resistant Staphylococcus aureus (MRSA) with the USA300 pulsed-field gel electrophoresis type causes most community-associated MRSA infections and is an increasingly common cause of health care-associated MRSA infections. USA300 probably emerged during the early 1990s. To assess the spatiotemporal diffusion of USA300 MRSA and USA100 MRSA throughout the United States, we systematically reviewed 354 articles for data on 33,543 isolates, of which 8,092 were classified as USA300 and 2,595 as USA100. Using the biomedical literature as a proxy for USA300 prevalence among genotyped MRSA samples, we found that USA300 was isolated during 2000 in several states, including California, Texas, and midwestern states. The geographic mean center of USA300 MRSA then shifted eastward from 2000 to 2013. Analyzing genotyping studies enabled us to track the emergence of a new, successful MRSA type in space and time across the country.
| S-EPMC4622244 | biostudies-literature
Project description:The translation inhibitor Linezolid is an important antibiotic of last resort against multiresistant gram-positive pathogens including MRSA. Linezolid is reported to specifically inhibit extracellular virulence factors, but the molecular cause is unknown. To elucidate the physiological response of S. aureus to Linezolid in general and the possible inhibition of virulence factors specifically we performed a holistic study. We added Linezolid to logarithmically growing S. aureus cells and analysed the Linezolid stress response with transcriptomics, quantitative proteomics and microscopy experiments.
2016-03-18 | PXD001622 | Pride
Project description:The translation inhibitor Linezolid is an important antibiotic of last resort against multiresistant gram-positive pathogens including MRSA. Linezolid is reported to specifically inhibit extracellular virulence factors, but the molecular cause is unknown. To elucidate the physiological response of S. aureus to Linezolid in general and the possible inhibition of virulence factors specifically we performed a holistic study. We added Linezolid to logarithmically growing S. aureus cells and analysed the Linezolid stress response with transcriptomics, quantitative proteomics and microscopy experiments.
2016-03-18 | PXD001659 | Pride
Project description:BackgroundCommunity-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is a significant bacterial pathogen that poses considerable clinical and public health challenges. The majority of the CA-MRSA disease burden consists of skin and soft tissue infections (SSTI) not associated with significant morbidity; however, CA-MRSA also causes severe, invasive infections resulting in significant morbidity and mortality. The broad range of disease severity may be influenced by bacterial genetic variation.ResultsWe sequenced the complete genomes of 36 CA-MRSA clinical isolates from the predominant North American community acquired clonal type USA300 (18 SSTI and 18 severe infection-associated isolates). While all 36 isolates shared remarkable genetic similarity, we found greater overall time-dependent sequence diversity among SSTI isolates. In addition, pathway analysis of non-synonymous variations revealed increased sequence diversity in the putative virulence genes of SSTI isolates.ConclusionsHere we report the first whole genome survey of diverse clinical isolates of the USA300 lineage and describe the evolution of the pathogen over time within a defined geographic area. The results demonstrate the close relatedness of clinically independent CA-MRSA isolates, which carry implications for understanding CA-MRSA epidemiology and combating its spread.
| S-EPMC3598774 | biostudies-literature
Project description:Previous studies showed that sub-MIC levels of β-lactam antibiotics stimulate biofilm formation in most methicillin-resistant Staphylococcus aureus (MRSA) strains. Here, we investigated this process by measuring the effects of sub-MIC amoxicillin on biofilm formation by the epidemic community-associated MRSA strain USA300. We found that sub-MIC amoxicillin increased the ability of USA300 cells to attach to surfaces and form biofilms under both static and flow conditions. We also found that USA300 biofilms cultured in sub-MIC amoxicillin were thicker, contained more pillar and channel structures, and were less porous than biofilms cultured without antibiotic. Biofilm formation in sub-MIC amoxicillin correlated with the production of extracellular DNA (eDNA). However, eDNA released by amoxicillin-induced cell lysis alone was evidently not sufficient to stimulate biofilm. Sub-MIC levels of two other cell wall-active agents with different mechanisms of action-d-cycloserine and fosfomycin-also stimulated eDNA-dependent biofilm, suggesting that biofilm formation may be a mechanistic adaptation to cell wall stress. Screening a USA300 mariner transposon library for mutants deficient in biofilm formation in sub-MIC amoxicillin identified numerous known mediators of S. aureus β-lactam resistance and biofilm formation, as well as novel genes not previously associated with these phenotypes. Our results link cell wall stress and biofilm formation in MRSA and suggest that eDNA-dependent biofilm formation by strain USA300 in low-dose amoxicillin is an inducible phenotype that can be used to identify novel genes impacting MRSA β-lactam resistance and biofilm formation.
| S-EPMC4862544 | biostudies-literature