MRSA pseudo-outbreak
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ABSTRACT:
PROVIDER: PRJEB58118 | ENA |
REPOSITORIES: ENA
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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:A strategy for the high-throughput screening of a peptide nucleic acid (PNA) encoded peptide library to allow the identification of MRSA and MSSA selective peptides including AMPs. This novel screening approach allows simultaneous screening of cell selective peptides with different uptake mechanisms including lytic peptides and non-lytic CPPs. MRSA and MSSA were incubated with Library-18 (50 uM; corresponding to 39 nM of each library member) under short incubation times (30 min) to ensure collection of both live and apoptotic cells, which allowed selection of lytic peptides as well as non-lytic CPPs. Incubation was followed by washing and lysis and the intracellular and membrane associated library members were extracted and purified by filter centrifugation (between 3,000 and 10,000 Da). The extracted PNA tags were hybridized onto custom designed microarrays. Each microarray consisted of 4 sub-arrays of 44,000 features each with 33 replicates of each oligonucleotide complementary to each member of the library as well as 1232 non-coding negative controls. Microarray scanning and data analysis (BlueFuse, BlueGenome) was used to extract the intensity of the FAM label, thereby giving the relative amount of PNA hybridized to each spot and the identity of the peptide.
2012-12-01 | E-MEXP-3327 | biostudies-arrayexpress
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: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:A recent study reported that daptomycin-resistant MRSA (DAPR) strain biofilm is more resistant to daptomycin and vancomycin, as compared to the WT strain biofilm. This pose a great danger since DAPR MRSA is prevalent in clinics and they often form biofilms in medical devices. In this study, we investigate the anti-biofilm activity of elasnin against DAPR MRSA biofilms, and we observed that elasnin is not only effective to eradicate the biofilm of the DAPR strain, but it shows a superior activity compared to the susceptible WT strain. Using proteomics, we compared the proteome profile of the DAPR and the WT strain biofilm cells under elasnin treatment to reveal why elasin is superior against the DAPR strain. Besides, we also employed adaptive laboratory evolution (ALE) experiment by repetitively treating MRSA culture with high dose of elasnin, and generated evolved MRSA strain with increased elasnin tolerance. Using quantitative proteomics, we compared the proteome differences in the elasnin-susceptible WT MRSA and elasnin-tolerant evolved strain.
2021-11-11 | PXD024005 | Pride
Project description:The oceanic diatom Pseudo-nitzschia granii was cultured in the laboratory under steady-state iron-replete and iron-limited conditions. Transcriptomic and proteomic analyses were performed to determine how this organism reorganizes major metabolic processes as a function of iron supply.
2018-08-21 | PXD009698 | Pride
Project description:BackgroundMethicillin resistant Staphylococcus aureus (MRSA) is a major burden for hospitals globally. However, in the Netherlands, the MRSA prevalence is relatively low due to the 'search and destroy' policy. Routine multiple-locus variable-number of tandem repeat analysis (MLVA) of MRSA isolates supports outbreak detection. However, whole genome multiple locus sequence typing (wgMLST) is superior to MLVA in identifying (pseudo-)outbreaks with MRSA. The present study describes a pseudo-outbreak of MRSA at the bacteriology laboratory of a large Dutch teaching hospital.MethodsAll staff members of the bacteriology laboratory of the Elisabeth-TweeSteden hospital were screened for MRSA carriage, after a laboratory contamination with MRSA was suspected. Clonal relatedness between the index isolate and the MRSA isolates from laboratory staff members and all previous MRSA isolates from the Elisabeth-TweeSteden hospital with the same MLVA-type as the index case was examined based on wgMLST using whole genome sequencing.ResultsOne of the staff members was identified as the probable source of the laboratory contamination, because of carriage of a MRSA possessing the same MLVA-type as the index case. Eleven other isolates with the same molecular characteristics were found in the database, of which seven were retrospectively suspected of contamination. Clonal relatedness was found between ten isolates, including the isolate found in the staff member and the MRSA found in the index patient with a maximum of eleven alleles difference. All isolates were epidemiologically linked through the laboratory staff member, who had worked on all these cultures.ConclusionsThe present study describes a MRSA pseudo-outbreak over a 2.5-year period due to laboratory contamination caused by a MRSA carrying laboratory staff member involving nine patients. In case of unexpected bacteriological findings, the possibility of a laboratory contamination should be considered.
| S-EPMC9814305 | biostudies-literature
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: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