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ABSTRACT:
PROVIDER: PRJNA702288 | ENA |
REPOSITORIES: ENA
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Project description:Staphylococcus aureus (S. aureus) is a known pathogen able to infect humans and animals. Human S. aureus isolates are often associated with carriage of Sa3int prophages combined with loss of beta-hemolysin production due to gene disruption, whereas animal isolates are positive for beta-hemolysin associated with absence of Sa3int prophages. Sa3int prophages are known to contribute to staphylococcal fitness and virulence in human host by providing human-specific virulence factors encoded on the prophage genome. Strain-specific differences in regard to phage transfer, lysogenization and induction are attributable to yet unknown staphylococcal factors specifically influencing prophage gene expression. In this work we used tagRNA-sequencing approach to specifically search for these unknown host factors and differences in prophage gene expression. For this purpose, we established a workflow revealing the first direct comparison for differential gene expression analysis on two distinct single-lysogenic S. aureus isolates. Further, global gene expression patterns were investigated in two S. aureus isolates upon mitomycin C treatment and compared to uninduced conditions. This provides new insights into the tightly linked host-phage interaction network.
2022-10-03 | GSE214523 | GEO
Project description:S. aureus and S. epidermidis were challenged with D-sphingosine, an antimicrobial lipid similar to sphingosines found in the major staphylococcal niche- human skin. Comparison of responses was used to identify resistance mechanisms and likely mode of action
2020-10-01 | E-MTAB-9272 | biostudies-arrayexpress
Project description:Atopic dermatitis (AD) is a chronic pruritic inflammatory skin disease. We recently described an animal model in which repeated epicutaneous applications of a house dust mite extract and Staphylococcal enterotoxin B induced eczematous skin lesions. In this study we showed that global gene expression patterns are very similar between human AD skin and allergen/staphylococcal enterotoxin B–induced mouse skin lesions, particularly in the expression of genes related to epidermal growth/differentiation, skin barrier, lipid/energy metabolism, immune response, or extracellular matrix. In this model, mast cells and T cells, but not B cells or eosinophils, were shown to be required for the full expression of dermatitis, as revealed by reduced skin inflammation and reduced serum IgE levels in mice lacking mast cells or T cells (TCRb-/- or Rag1-/-). The clinical severity of dermatitis correlated with the numbers of mast cells, but not eosinophils. Consistent with the idea that T helper type 2 (Th2) cells play a predominant role in allergic diseases, the receptor for the Th2-promoting cytokine thymic stromal lymphopoietin and the high-affinity IgE receptor, FceRI, were required to attain maximal clinical scores. Therefore, this clinically relevant model provides mechanistic insights into the pathogenic mechanism of human AD. A total of six samples were analyzed. Back skin samples from healthy or AD-induced C57BL/6, PLC-beta 3 KO (C57BL/6 background), and NC/Nga mice were collected for total RNA extraction. Pooled RNA from 2-4 mice per condition were used for analysis.
2013-12-10 | E-GEOD-53132 | biostudies-arrayexpress
Project description:The present work comprises the study of wound pathogenic bacteria as part of a community. It considers the interactions of two different S. aureus isolates with B. thuringiensis and K. oxytoca; all of them isolated from the same chronic wound of a patient with epidermolysis bullosa. Particular focus has been given on the interactions of S. aureus with other microbes due to its high prevalence among chronic wounds. During cultivation, no species performed as dominant or inhibited the growth of one another. Mass spectrometry was used to explore the inherent relationships between the staphylococcal strains and the coexisting bacteria exproteomes. The analysis showed an important reduction in the amount of staphylococcal cytoplasmic proteins when co-cultured with K. oxytoca and B. thuringiensis, this decrement did not occur with klebsiella and bacillus proteins. Interestingly, K. oxytoca and B. thuringiensis seemed to have a more evident response towards the presence of S. aureus in the culture, while the opposite was not observed with the staphylococcal isolates. Genomic analysis revealed isolate t13595 hypermutable characteristics, placing the interactions between staphylococcal isolates in the context of a chronic wound. Overall, the nature of the exoproteome variations among cultures suggests that adaptive mechanisms differ in all strains.
2018-10-17 | PXD005596 | Pride
Project description:Atopic dermatitis (AD) is a chronic pruritic inflammatory skin disease. We recently described an animal model in which repeated epicutaneous applications of a house dust mite extract and Staphylococcal enterotoxin B induced eczematous skin lesions. In this study we showed that global gene expression patterns are very similar between human AD skin and allergen/staphylococcal enterotoxin B–induced mouse skin lesions, particularly in the expression of genes related to epidermal growth/differentiation, skin barrier, lipid/energy metabolism, immune response, or extracellular matrix. In this model, mast cells and T cells, but not B cells or eosinophils, were shown to be required for the full expression of dermatitis, as revealed by reduced skin inflammation and reduced serum IgE levels in mice lacking mast cells or T cells (TCRb-/- or Rag1-/-). The clinical severity of dermatitis correlated with the numbers of mast cells, but not eosinophils. Consistent with the idea that T helper type 2 (Th2) cells play a predominant role in allergic diseases, the receptor for the Th2-promoting cytokine thymic stromal lymphopoietin and the high-affinity IgE receptor, FceRI, were required to attain maximal clinical scores. Therefore, this clinically relevant model provides mechanistic insights into the pathogenic mechanism of human AD.
2013-12-10 | GSE53132 | GEO
Project description:Methicillin-resistant Staphylococcus aureus (MRSA) is the causative agent of serious hospital- and community-associated infections. Due to the global rise in community-associated MRSA, the respective lineages are increasingly introduced into hospitals. This raises the question whether and, if so, how they adapt to this new environment. The present study was aimed at investigating how MRSA isolates of the USA300 lineage, infamous for causing infections in the general population, have adapted to the hospital environment. To this end, a collection of community- and hospital-associated USA300 isolates was compared by RNA-sequencing. Here we report that merely 460 genes were differentially expressed between these two epidemiologically distinct groups, including genes for virulence factors, oxidative stress responses and the purine, pyrimidine and fatty acid biosynthetic pathways. Differentially regulated virulence factors included leukotoxins and phenol-soluble modulins, implicated in staphylococcal escape from immune cells. We therefore investigated the ability of the studied isolates to survive internalization by human neutrophils. This showed that the community-associated isolates have the highest neutrophil-killing activity, while the hospital-associated isolates are better adapted to intra-neutrophil survival. Importantly, the latter trait protects internalized staphylococci against a challenge with antibiotics. We therefore conclude that prolonged intra-neutrophil survival serves as a relatively simple early adaptation of S. aureus USA300 to the hospital environment where antibiotic pressure is high.
2016-11-02 | GSE89394 | GEO
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.
2011-12-31 | E-GEOD-26585 | biostudies-arrayexpress
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