SCREENING OF GENES ENCODING POTENTIAL VIRULENCE FACTORS IN ENTEROCOCCUS FAECIUM AND GAP CLOSURE OF THE reppLG1 REPLICON CLASS PLASMID IN E. FAECIUM

摘要

The aims of this study were to obtain a circular map of a pLG1 replicon type plasmid in E. faecium (TUH 56-32), derived from the trans-conjugation between E. faecium (K60-39), donor and (BM4105-RF) recipient strains and also to detect the presence of and describe the prevalence of selected open reading frames (ORF) from a clinical and non-clinical collection of E. faecium and E. faecalis strains. The DNA sequence of E. faecium (TUH56-32) plasmid was subjected to gaps closure. Gaps closure was performed by PCR to obtain a circular map of the plasmid sequence. To detect the presence of ORFs total DNA was extracted from a clinical and non-clinical collection of 150 isolates which consisted of 116 E. faecium and 34 E. faecalis. PCR was applied to detect the presence of ORFs.The gaps closing experiment was not accomplished and therefore did not give a circular DNA. However, the screening experiment was completed and the detection and description of ORFs among E. faecium showed that isolates from blood cultures harboured more ORFs than those of other clinical and non-clinical sources. Those of non-clinical cultures however lacked three of the tested ORFs. The prevalence was higher among clinical isolates of all sources compared to non-clinical isolates. Isolates of E. faecium detected more prevalently to all ORFs than E. faecalis. The isolates derived from blood cultures were highly enriched with all four ORFs compared to isolates from other clinical sources. Blood culture isolates harbouring all ORFs differed significantly to those of other clinical sources. In summary, the tested ORFs were overrepresented in blood culture isolates of E. faecium followed by other clinical isolates.