Linkage of vancomycin and high-level gentamicin resistance genes on the same plasmid in a clinical isolate of Enterococcus faecalis

Abstract

A transferable 55-MDa plasmid which encoded resistance to both vancomycin and high concentrations of gentamicin was identified in a clinical isolate of Enterococcus faecalis. The plasmid hybridized with probes for the vanB and aac6'aph2" resistance genes. This is the first report of linkage of glycopeptide and high-level aminoglycoside resistance genes in an Enterococcus sp.

Characterization of transposon Tn1549, conferring VanB-type resistance in Enterococcus spp. The GenBank accession number for the 33803 bp sequence of Tn1549 is AJ192329.

“…Transfer of vancomycin resistance from clinical isolate C68 to E. faecium GE-1 is associated with the transfer of ampicillin and tetracycline resistances and with acquisition of an approximately 130-160 kb segment of chromosomal DNA (Carias et al, 1998). In E. faecalis E93\268 and E. faecium 654 clinical isolates, resistance to vancomycin was found to be associated with a vanB gene cluster carried by plasmids pIP834 and pIP835, respectively (Woodford et al, 1995a, b).…”

“…Enterococcus faecalis E93\268, isolated from a blood culture at 0002-4032 # 2000 SGM Addenbrooke's Hospital in Cambridge, UK, was resistant to high concentrations of gentamicin (MIC 2000 mg l − ") and expressed the VanB phenotype, i.e. resistance to vancomycin (MIC 32 mg l − ") and susceptibility to teicoplanin (MIC 1 mg l − ") (Woodford et al, 1995a). E. faecium 654 was isolated in the renal unit of the Queen Elizabeth Hospital in Birmingham, UK, and is also of the VanB type (Woodford et al, 1995b).…”

“…Vancomycin-resistant E. faecalis E93\268 and E. faecium 654 were isolated in 1994 in the United Kingdom. Resistance in these strains was associated with the presence of the vanB gene, borne by conjugative plasmids (Woodford et al, 1995a, b). Here we report the characterization of the 34 kb transposon Tn1549 responsible for vancomycin resistance.…”

“…Hybridization experiments indicated that vancomycin resistance in E. faecalis 268-10 and 654-6 was associated with the presence of the vanB gene borne by conjugative plasmids (Woodford et al, 1995a, b) that were designated pIP834 and pIP835, respectively. The retransfer of vancomycin resistance from E. faecalis 268-10 and 654-6 to E. faecalis BM4110 was determined and was found to occur at frequencies of 4n4i10 −' and 4i10 −# , respectively.…”

Prevalence of Enterococcal Infections and Their Antibiotic Susceptibility Pattern With Special Reference to Hlar in South East Rajasthan

“…5,6,7 High level aminoglycoside resistant Enterococci often have plasmids, which carry determinants encoding resistance to other antibiotics. It is notable that Woodford et al demonstrated linkage of the vancomycin resistance and high-level gentamicin resistance genes on the same plasmid in a clinical isolate of E. faecalis and the presence of the gentamicin resistance gene on a variety of physically distinct conjugative and non-conjugative plasmids in E. faecalis facilitates the wide dissemination of multidrugresistant strains with characteristics that allow them not only to persist but also to spread.…”