Project description:Staphylococcus haemolyticus is a skin commensal emerging as an opportunistic pathogen. Nosocomial isolates of S. haemolyticus are the most antibiotic resistant members of the coagulase negative staphylococci (CoNS), but information about other S.haemolyticus virulence factors is scarce. Bacterial virulence is mediated by membrane vesicles (MVs) which enable secretion and long distance delivery of bacterial effector molecules while protecting the cargo from proteolytic degradation from the environment. We wanted to determine if the MV protein cargo of S.haemolyticus is strain specific and enriched in certain MV associated proteins compared to the totalsecretome. The present study shows that both clinical and commensal S. haemolyticus isolates produce membrane vesicles. The MV cargo of both strains was enriched in proteins involved in adhesion and in acquisition of iron. The MV cargo of the clinical strain was further enriched in antimicrobial resistance proteins.
Project description:In this study, the adhesive and biofilm forming properties of ten clinical and ten commensal S. haemolyticus isolates were examined using standard adhesion and biofilm assays, in addition we selected one clinical S. haemolyticus isolate for bacterial surface shaving. The surface shaving approach was used to identify upregulated S. haemolyticus proteins subsequent to human keratinocyte colonization. Relative quantification of up and downregulated proteins was performed by labelling proteins with tandem mass tags (TMT), prior to Mass Spectrometry analysis.
Project description:BackgroundWe have compared the effects of conventional lactate-based peritoneal dialysis fluid (CPDF) with respect to bicarbonate/lactate-based fluid on peritoneal ultrafiltration (UF) and peritoneal permeability, and on variations on gene expression in cells isolated from effluents of patients' peritoneal bags.MethodsThis was a non-randomized sequential prospective study including all incident peritoneal dialysis (PD) patients (n?=?40) recruited in our centre. Peritoneal equilibration tests (PETs) were performed using CPDF or BPDF both containing 2.27% glucose during a 48-h interval in four different sequences. Gene expression variation of selected genes was measured by reverse transcription polymerase chain reaction in mesothelial cells obtained from the total drained fluid during the PET.ResultsIn the overall study, the use of BPDF was associated with significantly lower mass transfer area coefficient for urea and creatinine, longer accelerated peritoneal examination test times for urea and creatinine, lower total pore area available for exchange over diffusion distance and lower UF. There were no differences in the gene expression of aquaporins 1-3, endothelial and inducible nitric oxide synthase (NOS3 and NOS2), or interleukin-6. The SNAIL and E-CADHERIN gene expression normalized ratio was evaluated in peritoneal effluents of cells obtained from CPDF and BPDF. We observed that the SNAIL/E-CADHERIN mRNA ratio decreased when the dialysis sequence started with BPDF and went on to CPDF, but not when the sequence was the opposite.ConclusionThis study shows that those patients who started PD treatment with BPDF were characterized by a better biocompatibility profile. BPDF associates with lower peritoneal permeability to small molecules and lower UF.