Analysis of antimicrobial resistance in Enterococcus isolates from 2009 to 2013

Objective To investigate the clinical distribution and antimicrobial resistance of Enterococcus isolates in order to provide reference for rational use of antimicrobial agents.Methods The clinical data of 855 cases of nosocomial enterococcal infection were analyzed retrospectively.Bacterial identification and antimicrobial susceptibility testing were performed by automatic VITEK2 Compact system.The susceptibility of high-level gentamicin-resistant(HLGR)strains were tested by Kirby-Bauer method.The data were analyzed by WHONET software.Results A total of 465 isolates of E.faeciumand 347 isolates of E.faecalis were collected,mainly from urine,drainage fluids,sputum,and wound secretions.More than 71.4%of the E.faeciumisolates were resistant to ampicillin,ciprofloxacin,penicillin and levofloxacin,significantly higher than those of E.faecalis(≤ 37.2%).On the other hand,76.4% and 72.6% of the E.faecalis isolates were resistant to tetracycline and quinupristin/dalfopristin,respectively,significantly higher than those of E.faecium(59.4% and 5.6%,respectively)(P0.001).The results of antimicrobial susceptibility testing showed that both Enterococcus species were highly resistant to erythromycin(≥ 76.9%),but least resistant to vancomycin and teicoplanin(≤ 2.2%).Overall,537(66.1%)HLGR strains were screened out from812 strains of E.faeciumand E.faecalis.Conclusions Enterococcal infection is mainly due to E.faeciumand E.faecalis.E.faeciumstrains generally show higher resistance to antibiotics than E.faecalis.Vancomycin resistance has been identified in some clinical Enterococcus isolates.Most enterococcal strains are high-level gentamicin resistant.Appropriate antimicrobial therapy should be based on the results of antimicrobial susceptibility testing.