Exploring the transcriptome of Staphylococcus aureus in its environmental niche
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ABSTRACT:
ORGANISM(S): Staphylococcus aureus
PROVIDER: GSE73485 | GEO | 2016/09/19
SECONDARY ACCESSION(S): PRJNA297140
REPOSITORIES: GEO
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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>
2011-04-15 | E-BUGS-102 | biostudies-arrayexpress
Project description:Staphylococcus aureus is an important human pathogen and commensal, where the human nose is the predominant reservoir. To better understand its behavior in this environmental niche, RNA was extracted from the anterior nares of three documented S. aureus carriers and the metatranscriptome analyzed by RNAseq. In addition, the in vivo transcriptomes were compared to previously published transcriptomes of two in vitro grown S. aureus strains. None of the in vitro conditions, even growth in medium resembling the anterior nares environment, mimicked in vivo conditions. Survival in the nose was strongly controlled by the limitation of iron and evident by the expression of iron acquisition systems. S. aureus populations in different individuals clearly experience different environmental stresses, which they attempt to overcome by the expression of compatible solute biosynthetic pathways, changes in their cell wall composition and synthesis of general stress proteins. Moreover, the expression of adhesins was also important for colonization of the anterior nares. However, different S. aureus strains also showed different in vivo behavior. The assessment of general in vivo expression patterns and commonalities between different S. aureus strains will in the future result in new knowledge based strategies for controlling colonization.
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Project description:The transcription level of a rex-deficient S. aureus mutant in comparison to its parental strain S. aureus SH1000 was analyzed using DNA microarrays.
2009-12-31 | GSE17128 | GEO
Project description:in vitro comparison between two MRSA grown in rich (BHI) and poor media (SNM), compared with the nasal metatranscriptome reads of S. aureus. Global expression profile of two MRSA strains of S.aureus harvested in two different growth phases and compared with a metatranscriptome nose sample of a S. aureus carrier.
2015-01-05 | E-GEOD-56294 | biostudies-arrayexpress
Project description:The opportunistic pathogen Staphylococcus aureus is carried asymptomatically by about one-third of the human population. Body sites known to be colonized by S. aureus are the skin, nasopharynx and gut. In particular, the mechanisms that allow S. aureus to pass the gut epithelial barrier and to invade the bloodstream are poorly understood. Therefore, our present study was aimed at investigating possible differences between gut-colonizing and bacteremia isolates of S. aureus. To this end, 74 gut-colonizing isolates from healthy individuals and 144 blood-culture isolates were characterized by whole-genome sequencing. Subsequently, the cellular and extracellular proteomes of six representative isolates were examined by mass spectrometry. Lastly, the virulence potential of these isolates was evaluated using infection models based on human gut epithelial cells, blood cells, and a small animal infection model. Intriguingly, our results show that gut-colonizing and bacteremia isolates with the same sequence type (ST1 or ST5) are very similar at the genomic and proteomic levels. Nonetheless, they display differences in virulence, but gut-colonizing isolates may be more virulent than bacteremia isolates and vice versa. Importantly, we show that the main decisive factor preventing infection of gut epithelial cells in vitro is the presence of a tight barrier. Based on our present observations, we propose that the integrity of the gut epithelial layer, rather than the pathogenic potential of a gut-colonizing S. aureus strain, is the main decisive factor that determines whether this colonizer will become an invasive pathogen.
2023-03-11 | PXD030971 | Pride
Project description:Therapy of Staphylococcus aureus bacteremia is often ineffective, even under optimal conditions, and adapted subclones with attenuated agr-mediated virulence activation are associated with persistent infection and mortality. To understand how apparent loss of virulence leads to increased mortality, we sequenced complete genomes from clone pairs from colonizing and infected sites of patients in whom S. aureus demonstrated a within-host downshift in agr function in the infecting isolate. Clone pairs with a downshift in agr function showed substantial genetic divergence compared to wild-type pairs from controls. Complementation studies further identified an agr-defective bacteremic strain that was highly virulent in vivo, which we linked to a mutation that restored expression of the agr-regulated ess/Type-VII secretion system; a known virulence factor. Our results suggest that selection pressure during invasive infection is strong enough to mutationally bypass agr-deficiency associated loss of virulence, and that efforts to suppress agr function may need to be reconsidered.
2019-08-14 | GSE102637 | GEO
Project description:S. aureus has a propensity to cause endocarditis; diabetes mellitus is a frequent underlying comorbitity in patents with S. aureus endocarditis. S. aureus Affymetrix GeneChips were used to compare S. aureus expression properties in cardiac vegatations isolated from diabetic and nondiabetic rats. S. aureus Affymetrix GeneChips were also used to compare the S. aureus expression properties of cardiac vegatations (both diabetic and nondiabetic) in comparsions to planktonic cells. Few differences were observed between the expression properties of S. aureus harvested from diabetic vs. nondiabetic cardiac vegatations. Significant differences were observed between the expression properties of S. aureus harvested from cardiac vegetations in comparison to exponential and/or stationary phase planktonically grown cells.
2014-11-01 | GSE62390 | GEO
Project description:Whole-genome analysis by 62-strain microarray showed variation in resistance and virulence genes on mobile genetic elements (MGEs) between 40 isolates of methicillin-resistant Staphylococcus aureus (MRSA) strain CC22-SCCmecIV but also showed (i) detection of two previously unrecognized MRSA transmission events and (ii) that 7/8 patients were infected with a variant of their own colonizing isolate. [Data is also available from http://bugs.sgul.ac.uk/E-BUGS-128]
2012-10-29 | E-BUGS-128 | biostudies-arrayexpress
Project description:Staphylococcus aureus from healthy human nose
| PRJNA591785 | ENA
Project description:There is evidence that MRSA ST398 of animal origin is only capable of temporarily occupying the human nose, and it is therefore, often considered a poor human colonizer.We inoculated 16 healthy human volunteers with a mixture of the human MSSA strain 1036 (ST931, CC8) and the bovine MSSA strain 5062 (ST398, CC398), 7 weeks after a treatment with mupirocin and chlorhexidine-containing soap. Bacterial survival was studied by follow-up cultures over 21 days. The human strain 1036 was eliminated faster (median 14 days; range 2-21 days) than the bovine strain 5062 (median 21 days; range 7-21 days) but this difference was not significant (pM-bM-^@M-^J=M-bM-^@M-^J0.065). The bacterial loads were significantly higher for the bovine strain on day 7 and day 21. 4/14 volunteers (28.6%) showed elimination of both strains within 21 days. Of the 10 remaining volunteers, 5 showed no differences in bacterial counts between both strains, and in the other 5 the ST398 strain far outnumbered the human S. aureus strain. Within the 21 days of follow-up, neither human strain 1036 nor bovine strain 5062 appeared to acquire or lose any mobile genetic elements. In conclusion, S. aureus ST398 strain 5062 is capable of adequately competing for a niche with a human strain and survives in the human nose for at least 21 days. [Data is also available from http://bugs.sgul.ac.uk/E-BUGS-131]
2012-10-29 | E-BUGS-131 | biostudies-arrayexpress