Similar Datasets
Project description:Purpose: Staphylococcus aureus is a highly successful human pathogen responsible for wide range of infections. In this study, we provide insights into the virulence, pathogenicity, and antimicrobial resistance determinants of methicillin susceptible and methicillin resistant Staphylococcus aureus (MSSA; MRSA) recovered from non-healthcare environments. Experiment design: Three environmental MSSA and three environmental MRSA were selected for proteomic profiling using iTRAQ MS/MS. Gene Ontology (GO) Annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) Pathway Annotation were applied to interpret the functions of the proteins detected. Results: 792 proteins were identified in MSSA and MRSA. Comparative analysis of MRSA and MSSA revealed that 8 of out 792 proteins were up-regulated and 156 down-regulated. Differentially abundant proteins were predominantly involved in catalytic and binding activity. Among 164 proteins that had differences in abundance, 29 proteins were involved in pathogenesis, antimicrobial activities，stress response, mismatch repair and cell wall synthesis. Twenty-two proteins associated with pathogenicity, including spa, sbi, clfA and dlt were up-regulated in MRSA. Moreover, the up-regulated pathogenic protein entC2 in MSSA was determined to be a super antigen potentially capable of triggering toxic shock syndrome in the host. Conclusions: Enhanced pathogenicity, antimicrobial activity and stress response were observed in MRSA compared to MSSA.
2020-01-09 | PXD014478 | Pride
Project description:Previous studies have documented the diversity of genetic background of methicillin-resistant S. aureus (MRSA) strains associated with healthcare (HA-MRSA), community (CA-MRSA) and livestock (LA-MRSA). The accessory and core-variable genome content of those strains remain largely unknown. To compare the composition of accessory and core-variable genome of Belgian MRSA strains according to host, population setting and genetic background, representative strains of HA- (n=21), CA- (n = 13) and ST398 LA-MRSA (n = 18) were characterized by a DNA-microarray (StaphVar Array) composed of oligonucleotide probes targeting ~400 resistance, adhesion and virulence associated genes.ST398 strains displayed very homogenous hybridization profiles (>94% gene content homology) irrespective of their host origin. This “ST398-specific” genomic profile was not distantly demarked from those of certain human-associated lineages but lacked several virulence- and colonization-associated genes harbored by strains of human origin, such as genes encoding proteases, haemolysins or adhesins. No enterotoxin gene was found among ST398 strains. In conclusion, our findings are consistent with a non-human origin of this ST398 lineage but suggest that it might have the potential to adapt further to the human host.
2010-11-15 | GSE20541 | GEO
Project description:Methicillin-resistant Staph. Aureus (MRSA) is a common cause of severe pneumonia and sepsis that can lead to Acute Respiratory Distress Syndrome (ARDS). MRSA causes lung endothelial cell (EC) dysfunction, a critical step in the pathogenesis and progression of lung injury. Our previous studies have demonstrated that FTY720 S-phosphonate (Tysiponate, Tys), an analog of sphingosine-1-phosphate, ameliorates MRSA-induced lung EC activation and barrier disruption (PMID: 35015568). To advance our mechanistic understanding of MRSA and Tys effects on lung EC, we investigated associated epigenetic changes. Specifically, we studied histone lysine acetylation, which is a central epigenetic alteration that has been linked to gene transcription and functional regulation of endothelial responses to inflammatory stimuli. We therefore determined the effects of MRSA exposure in the presence or absence of Tys on lung EC acetylation at the 9th lysine residue of the histone H3 protein (H3K9ac), which is an important chromatin modification associated with active promoters and gene activation. ChIP-seq analysis was employed to perform an unbiased genome-wide profiling of H3K9ac epigenetic patterns in human lung EC. This analysis identified multiple genes that are differentially targeted by acetylation when EC are exposed to MRSA±Tys.
2025-01-28 | GSE274958 | GEO
Project description:The success of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) as pathogens is due to a combination of antibiotic resistance with high virulence. However, evolution of the exceptional virulence potential of CA-MRSA is not understood. Our previous study indicated that differential gene expression contributes substantially to this process. Thus, we here investigated the role of the pivotal virulence gene regulatory system agr in the most prevalent CA-MRSA strain USA300. Using a mouse subcutaneous infection model, we show that agr is essential for the development of CA-MRSA skin infections, the most frequent manifestation of disease caused by CA-MRSA. Furthermore, genome-wide analysis of gene expression revealed significant differences in agr-dependent virulence gene regulation between CA-MRSA, HA-MRSA, and laboratory strains. Our findings demonstrate that agr functionality is critical for CA-MRSA disease and indicate that an adaptation of the agr regulon to optimize expression of a broad set of virulence determinants may have contributed to the evolution of exceptionally pronounced virulence of CA-MRSA strains. Keywords: wild type vs mutant
2011-03-29 | GSE18793 | GEO
Project description:Staphylococcus aureus can cause a broad spectrum of diseases that vary widely in clinical presentation and disease severity[121]. Methicillin-Resistant S. aureus (MRSA) strains first described in the 1960’s[122] were hospital acquired (HA MRSA), however in the 1990’s, community-associated MRSA strains (CA MRSA) were identified and are considered to be more virulent[16]. Therapeutics and management of MRSA focuses on novel antibacterials and vaccines targeting virulence factors. To date no clinical trials for vaccines have succeeded[123] due to the poor understanding of the pathogenic mechanisms exhibited by S.aureus.We investigated the differential gene expression of four clinical MRSA strains in vitro, belonging to HA and CA MRSA, at the stationary and exponential growth phases, using RNA-seq on the Ion torrent next generation sequencing platform. This study reveals the high diversity of virulence trait expression among MRSA strains within strains as well as between different growth phases, and also suggests potential factors other than PVL that contributes to enhanced virulence in CA MRSA
2020-01-07 | GSE70636 | GEO
Project description:Methicillin-resistant Staphylococcus aureus (MRSA) is a major hospital- and community-acquired pathogen, but the mechanisms underlying host-defense to MRSA remain poorly understood. Here, we investigated the role of IL-21 in this process. When administered intra-tracheally into wild-type mice, IL-21 induced granzymes and augmented clearance of pulmonary MRSA but not when neutrophils were depleted or a granzyme B inhibitor was added. Correspondingly, IL-21 induced MRSA killing by human peripheral blood neutrophils. Unexpectedly, however, basal MRSA clearance was enhanced when IL-21 signaling was blocked, both in Il21r KO mice and in wild-type mice injected with IL-21R-Fc fusion-protein. This correlated with increased type I interferon and an IFN-related gene signature, and indeed anti-IFNAR1 treatment diminished MRSA clearance in these animals. Moreover, we found that IFNβ induced granzyme B and promoted MRSA clearance in a granzyme B-dependent fashion. These results reveal an interplay between IL-21 and type-I IFN in the innate immune response to MRSA.
2019-04-22 | GSE129093 | GEO
Project description:Staphylococcus aureus can cause serious skin, respiratory, and other life-threatening invasive infections in humans, and methicillin-resistant S. aureus (MRSA) strains have been acquiring increasing antibiotic resistance. While MRSA was once mainly considered a hospital-acquired infection, the emergence of new strains, some of which are pandemic, has resulted in community-acquired MRSA infections that often present as serious skin infections in otherwise healthy individuals. Accordingly, defining the mechanisms that govern the activation and regulation of the immune response to MRSA is clinically important and could lead to the discovery of much needed rational targets for therapeutic intervention. Because the cytokine thymic stromal lymphopoetin (TSLP) is highly expressed by keratinocytes of the skin3, we investigated its role in host-defense against MRSA. Here we demonstrate that TSLP acts on neutrophils to increase their killing of MRSA. In particular, we show that both mouse and human neutrophils express functional TSLP receptors. Strikingly, TSLP enhances mouse neutrophil killing of MRSA in both an in vitro whole blood killing assay and an in vivo skin infection model. Similarly, TSLP acts directly on purified human blood neutrophils to reduce MRSA burden. Unexpectedly, we demonstrate that TSLP mediates these effects both in vivo and in vitro by engaging the complement C5 system. Thus, TSLP increases MRSA killing in a neutrophil- and complement-dependent manner, revealing a key connection between TSLP and the innate complement system, with potentially important therapeutic implications for control of MRSA infection.
2016-11-18 | GSE73313 | GEO
Project description:Influenza-induced respiratory failure is substantially worsened by secondary bacterial infections such as methicillin-resistant Staphylococcus aureus (MRSA). The bidirectional interaction between the influenza-injured lung microenvironment and MRSA is poorly understood. By conditioning MRSA ex vivo in bronchoalveolar lavage (BAL) fluid collected from mice at various timepoints of influenza infection, we found that influenza-injured lung microenvironment induces MRSA to increase cytotoxin expression while decreasing metabolic pathways. This overall increase in MRSA virulence was dependent upon SaeRS, a bacterial two-component system. Once expressed by MRSA, these influenza-induced toxins (such as Hla and LukAB) interact with host heparan sulfate (HS) fragments shed into the airspace. Highly-sulfated HS fragments augmented Hla- and LukAB-toxicity in vitro and in vivo. Our findings indicate that post-influenza MRSA pneumonia is shaped by bidirectional host-pathogen interactions: host injury triggers changes in bacterial expression of toxins, the activity of which are then shaped by host-derived HS fragments.
2022-11-29 | GSE199708 | GEO
Project description:Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is an emerging threat to human health throughout the world. Rodent MRSA pneumonia models mainly focus on the early innate immune responses to MRSA infection. However, the molecular pattern and mechanisms of recovery from MRSA lung infection are largely unknown. In this study, a nonlethal mouse MRSA pneumonia model was employed to investigate events during lung recovery from MRSA infection. We compared lung bacterial clearance, bronchoalveolar lavage fluid (BALF) characterization, lung histology, and gene expression profiling between Day 1 and Day 3 post-MRSA infection. Compared to Day 1 post-infection, bacterial colony counts and both BALF total cell number and protein concentration significantly decreased at Day 3 post-infection. Lung cDNA microarray analysis identified 47 significantly up-regulated and 35 down-regulated genes (p<0.01, 1.5-fold change [up and down]). Changes in eight genes were confirmed by real-time PCR. The pattern of gene expression suggests lung recovery is characterized by enhanced cell division, vascularization, and wound healing and by adjustment in host adaptive immune responses. Collectively, this data helps elucidate the molecular mechanisms of lung recovery after MRSA infection.
2013-11-12 | GSE36587 | GEO