Detection of Transposon Tn5281 Mediating High-level Gentamicin Resistance in Enterococcus faecalis / 中华医院感染学杂志

ABSTRACT

OBJECTIVE To explore the role of Tn5281 in high-level gentamicin resistance(HLGR) of Enterococcus faecalis. METHODS Fifty four strains of HLGR E.faecalis were tested for Tn5281 by PCR method.The PCR products were confirmed by dot blot hybridization and sequencing.Filter mating method was used to investigate the conjugative plasmid transfer.Antimicrobial susceptibility test was performed by agar dilution method of CLSI/NCCLS. RESULTS Of 54 HLGR E.faecalis strains,27(50.0%) carried different types of Tn5281,with 6 strains carrying complete type,17 strains carrying truncated type Ⅰ(lacked IS256 in the right flanking extremity) and 4 strains carrying truncated type Ⅱ(lacked IS256 in the left flanking extremity).All types of transposons were loaded on plasmids. Among four HLGR E.faecalis in which Tn5281 was successfully transferred to recipient strains by filter mating method,one carried complete type and three carried truncated type Ⅰ.Tn5281 carrying strains had higher resistance rates to penicillin and ampicillin and lower resistance rates to tetracycline and chloramphenicol compared to the strains not carrying Tn5281.(CONCLUSIONS Tn5281) is commonly carried by HLGR E.faecalis.It may integrate into conjugative plasmids and play an important role in the dissemination of HLGR among E.faecalis.