Fluoroquinolone resistance and active drug efflux in Enterococci / 中华检验医学杂志

ABSTRACT

Objective To investigate the effect of reserpine,an efflux pumps inhibitor,on the activities of fluoroquinolones (FQNs) against Enterococci,and the distribution of efflux pump genes emeA and its correlation with the resistance of Enterococci.To elucidate the relationship between FQN resistance in Enterococci and active efflux.Methods One hundred isolates of enterococci were identified by VITEK microbe automatic system.The antibacterial agent susceptibility tests were performed by the disc diffusion method (K-B) in accordance with the CLSI standards.The minimum inhibitory concentration (MIC) of each FQN was tested by the agar dilution method,and the MIC changes were detected after adding reserpine.The distribution of emeA in 100 isolates of Enterococci was determined by PCR.Thex2 test was used to compare the differences of statistical results.Results After reserpine was used,three-FQN resistance in Enterococci was reduced.Ciprofloxacin,gatifloxacin and levofloxacin resistance was reduced from 42％ (42/100) to 28％ (28/100),from 30％ (30/100) to 17％ (17/100),and from 33％ (33/100) to 23％ (23/100),respectively.The positive rate of emeA gene in 100 strains of Enterococci was 55％ (55/100).There were 45 positive strains(72.6％) in 62 E.faecalis and 10 positive strains (26.4％) in 38 E.faecium.The positive rate of emeA gene in the resistant strains against ciprofloxacin,gatifloxacin and levofloxacin was 73.8％ (31/42),76.7％ (23/30),75.8％ (25/33),respectively,and the positive rate of emeA gene in the susceptible strains against above 3 antibacterials were 41.4％ (24/58),45.7％ (32/70),44.8％ (30/67).Efflux pump genes emeA in resistant strains is higher than the sensitive strains,with the statistically significant difference(x2 =13.02,8.13 and 8.57,P ＜ 0.005).Conclusions Reserpine could inhibit the active efflux of in FON Enterococci and reduce the MIC for drug-resistant strains in vitro.Multidrug-resistant efflux pump gene emeA was relevant to antimicrobial drug resistance in Enterococci.