Detection of Extended-Spectrum β-Lactamases and Analysis of Antibiotic Resistance in Clinical Isolates of Enterobacter cloacae

OBJECTIVE To determine the productive rates of extended spectrum β lactamases (ESBLs) in the clinical isolates of Enterobacter cloacae, and investigate their resistance to 11 kinds of antibiotics. METHODS To detect ESBLs, 47 strains of E. cloacae were determined by the double disk synergy tests which placing disks of ceftazidime, cefotaxime, ceftriaxone, aztreonam, and cefepime at distance of 20 mm (center to center) from disk containing amoxicillin plus clavulanate. Antibiotic susceptibility test was performed by Kirby Bauer disk diffusion method. The WHONET 5 software was used to analyze test results. RESULTS In this sample, the productive rate of ESBLs was 38.3%. ESBLs producing strains had higher resistance rate than that of non ESBLs producing ones. The resistance rates of antibiotics that could be used in empiric therapy to deal with E. cloacae infection were imipenem(0), amikacin(17.0%), ciprofloxacin(29.8%) and cefepime(38.3%). CONCLUSIONS The antibiotic resistance of E. cloacae in our hospital was very serious, and ESBLs were one of the major mechanisms. Imipenem, amikacin and ciproflozacin were recommended in empiric therapy to deal with E.cloacae infections.