Extended-spectrum β-lactamase detection and antibiotic resistance analysis of Escherichia coli in Macao

Objective To determine the distribution of the antibiotic resistance and the extended-spectrum beta-lactamase(ESBLs) producing of Escherichia coli(E.coli) in Macao,and to clarify the mechanism of E.coli resistant to single or multiple antibiotics in Macao.Methods A total of 209 clinical isolates of E.coli were collected from Conde S Januario Hospital and Kiang Wu hospital from both out-patients and hospitalized patients.The susceptibility tests of 17 routine antibiotics were conducted by disk diffusion method for gram-negative strains.The ESBLs phenotypes were determined by CLSI 2006 criteria.Results The sensitivity of 209 E.coli strains was 100% for imipenem and meropenem,91.3% for piperacillin/tazobactam,and 70.7% for amoxicillin/lavulanic acid.The drug resistance rates of E.coli were 81.3%,31.3%,66.8%,51.4%,50.2% and 49.5% for ampicillin,amikacin,tetracycline,ciprofloxacin,trimethoprim+ sulfamethoxazole and gentamicin,respectively.Among the group of cephalosporin,the resistance rates were 44.9%,45.0%,39.4%,32.0%,31.6% and 4.8% for cefpodoxime,cefazolin,cefuroxime,ceftriaxone,cefotaxime,and ceftazidime,respectively.The resistance rate was 24.4% for aztreonamand.The positive rate of ESBLs detection was 30.1%.Compared to the Non-ESBLs-producing group,ESBLs-producing group had significantly higher resistance rate to 13 routine antibiotics(P0.01),except to imipenem,meropenem,piperacillin/tazobactam,and tetracycline.Conclusions Except to imipenem and meropenem,E.coli resisted to other 15 routine antibiotics in different degrees,either in single or multiple drug resistance.Positive rate of ESBLs detected from E.coli was higher.This may be one of the most important reasons of E.coli multidrug resistance in Macao.