Resistance Analysis And Resistant Genes Of HLGR Strain In Enterococcal Bloodstream Infection

Objective To evaluate the clinical and microbiological characteristics of enterococcal bloodstream infections,and detect the resistant genes to understand its resistant mechanisms in order to treat infection diseases rationally in clinical practice.Methods In our hospital from October 2009 to December 2014,Enterococcus strains isolated bloodstream infections were collected and indentified by VITEK microbe automatic system.And resistance genes of high-level gentamicin(HLGR)strains were detected by using PCR.Results Among 459 bacteria strains of enterococci isolated,there were 292 strains of E.Faecium(63.62%),137 strains of E.Faecalis(29.85%).Most of them were isolated from department of ICU,nephrology,hepatobiliary surgery,Pediatrics and gastroenterology.Among 47 bacteria strains of enterococci bloodstream infections isolated,there were 44 resisted HLGR,that were 34 strains of E.Faecium(72.3%),10 strains of E.Faecalis(21.3%).The spectrum of antibacterial agent-resistant E.faecalis was significant difference with the E.faecium,compared with other widely-used antibiotics,such as penicillin,ampicillin,ciprofloxacin,moxifloxacin,levofloxacin,macrodantin.The rates of resistance to vancomycin,teicoplanin and linezolid were lower.The resistant rates of E.faecium to high-level gentamicin and high-level streptomycin were respectively 79.4% and 32.4%,and those of E.faecalis were respectively 60% and 40%.In E.faecium of the HLGR strains,the detectable rates of the aac(6')/aph(2''),aph(3')-? and ant(6)-?were respectively 96.3%,33.3% and 37.0%,but in E.faecalis,the rates were respectively 100%,33.3% and 50.0%.The resistance genes owned two or more aminoglycoside modifying enzyme(AME)of E.faecium and E.faecalis were respectively 37.0% and 50.0%.Conclusion E.faeciumis and E.faecalis responsible for the enterococcal bloodstream infections.E.faecium strains have higher resistance rates to most antimicrobial agents test than E.faecalis.The resistance genes in HLGR Enterococcus were based on aac(6')/aph(2''),and two or more of them were rising tendency.Therefore the resistance antimicrobial agents of Enterococcus as conditional pathogenicbacteria is not optimistic,and its pathogenicity and drug resistance of transfer is worth attention because it are widely used as probiotics.