Ontology highlight
ABSTRACT:
PROVIDER: PRJNA547605 | ENA |
REPOSITORIES: ENA
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Project description:Methicillin-resistant Staphylococcus aureus (MRSA) has evolved numerous antimicrobial resistance mechanisms and is identified as a serious public health threat by the World Health Organization and U.S. Centers for Disease Control and Prevention. The glycopeptide vancomycin (VAN) remains a cornerstone of therapy for severe MRSA infections despite increasing reports of therapeutic failure in hospitalized patients with bacteremia or pneumonia. Here we examined the effectiveness of MVs-derived methicillin-resistant SA (MRSA) to counteract vancomycin (VAN). We found that supplementation of a typical MIC assay using bacteriologic and tissue-mimicking media with purified MVs attenuated MRSA susceptibility to VAN but no other examined cell-wall targeting antibiotics. In addition, the purified MVs protected MRSA challenged with sub-therapeutic dosage of VAN against the host’s innate immune system. Additionally, the proteome of MV peptides from VAN exposed MRSA was characterized to determine if protein expression was altered.
2021-11-03 | PXD024232 | Pride
Project description:BACKGROUND: Meticillin-resistant Staphylococcus aureus (MRSA) infections remain important medical and veterinary challenges. The MRSA isolated from dogs and cats typically belong to dominant hospital-associated clones, in the UK mostly EMRSA-15 (CC22 SCCmecIV), suggesting original human-to-animal transmission. Nevertheless, little is known about host-specific genetic variation within the same S. aureus lineage. HYPOTHESIS/OBJECTIVES: To identify host-specific variation amongst MRSA CC22 SCCmecIV by comparing isolates from pets with those from in-contact humans using whole-genome microarray. METHODS: Six pairs of MRSA CC22 SCCmecIV from human carriers (owners and veterinary staff) and their respective infected in-contact pets were compared using a 62-strain whole-genome S. aureus microarray (SAM-62). The presence of putative host-specific genes was subsequently determined in a larger number of human (n = 47) and pet isolates (n = 93) by PCR screening. RESULTS: Variation in mobile genetic elements (MGEs) occurred frequently and appeared largE: The variation found amongst MGEs highlights that genetic adaptation in MRSA continues. However, host-specific MGEs were not detected, which supports the hypothesis that pets may not be natural hosts of MRSA CC22 and emphasizes that rigorous hygiene measures are critical to prevent contamination and infection of dogs and cats. The host specificity of individual heavy-metal resistance genes warrants further investigation into different selection pressures in humans and animals.
2013-11-02 | E-BUGS-138 | biostudies-arrayexpress
Project description:Methicillin-resistant Staphylococcus aureus (MRSA) is a major threat to human health. Rather than depend on creating new antibiotics (to which bacteria will eventually become resistant), we are employing antibiotic adjuvants that potentiate existing antibiotics. Based on our previous work, loratadine, the FDA-approvide antihistamine, effectively potentiates cell-wall active antibiotics in multiple strains of MRSA. Furthermore, loratadine and oxacillin helped disrupt preformed biofilms and stop them from initially forming in vitro. To gain biological insight into how this potentiation and biofilm inhibition occurs, we used RNA-seq on treated MRSA 43300 cultures to examine antibiotic adjuvant affects transcritome-wide.
2023-03-23 | GSE227099 | GEO
Project description:Staphylococcus aureus has been recognized as an important cause of human disease for more than 100 years. Resistance to multiple classes of antibiotics is becoming an increasingly difficult problem in the management of methicillin-resistant S. aureus (MRSA) and vancomycin-intermediate resistant S. aureus (VISA) infections. One approach to the MRSA and VISA problem, involves the discovery and development of new natural antimicrobials. The antimicrobial properties of essential oils of plant origin have been recognized for many years. In this study 0.1% of commercial cold pressed terpeneless Valencia orange oil (CPV) showed inhibitory and lytic activity against MRSA and VISA. To identify the mechanisms of action of CPV genomic response of CPV treated MRSA was analyzed by transcriptional profiling. Results showed alteration in the expression of cell wall peptidoglycan biosynthesis associated genes in the CPV treated cells. Transmission electron microscopic observation of CPV treated MRSA cells exhibited cell wall damage and cell lysis. Overall results of this study suggest that CPV may be a potential anti-staphylococcal agent for MRSA.
2011-11-08 | GSE33465 | 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) infections result in more than 200,000 hospitalizations and 10,000 deaths in the United States each year and remain an important medical challenge. To better understand the transcriptome of Staphylococcus aureus USA300 NRS384, a community-acquired MRSA strain, we have conducted an RNA-Seq experiment on WT samples.
2017-11-15 | GSE102279 | 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 Wild type vs mutant agr strains.
2011-03-29 | E-GEOD-18793 | biostudies-arrayexpress
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: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