Distribution of ESBLs-producing Escherichia coliinfections and drug resistance during 1999-2010

OBJECTIVE To investigate the clinical distribution and the drug resistance of ESBLs-producing Escherichia coli(E.coli) and thereafter provide bases for reasonable selection of antibiotics in the clinical practice.METHODS We retrospectively analyzed 5106 clinical isolates of E.coli from Jan 1999 to Dec 2010,the strains were identified by API and VITEK-2 system of Bio-Merieux of France,the drug susceptibility testing was determined by Kirby-Bauer method,the antimicrobial resistance was analyzed by WHONET 5.4 software.Double-disc synergy test and disk diffusion confirmatory test were employed to detect extended-spectrum β-lactamases.RESULTS The detection rate of ESBLs-producing E.coli increased from 16.27% in 1999 to 55.70% in 2010,respectively;E.coli strains were mainly isolated from urine,accounting for 29.13%,followed by the blood(20.06%) and sputum(18.36%);the majority of the strains were isolated from surgery and medicine wards;as compared with non-ESBLs-producing E.coli,the resistance rates of ESBLs-producing E.coli to non-β-lactamase antibiotics such as amikacin and levofloxacin significantly increased,with statistical significance(P0.01),both ESBLs-producing and non-ESBLs-producing E.coli isolates were highly susceptible to imipenem and meropenem,the drug resistance rates were less than 1.00%.CONCLUSION The detection rate of ESBLs-producing E.coli increases year by year;ESBLs-producing E.coli shows multidrug resistance to antibiotics including non-β-lactam antibiotics;the drug resistance rate of ESBLs-producing E.coli is higher than that of non-ESBLs-producing E.coli,which remain highly susceptible to carbapenems.