Antimicrobial resistance of 235 strains of Escherichia coli isolated from patients with bloodstream infection / 中国感染控制杂志

ABSTRACT

Objective To investigate antimicrobial resistance of Escherichia coli (E.coli )isolated from patients with bloodstream infection,and provide evidence for rational use of antimicrobial agents in clinical practice.Methods BacT/A-lert automated blood culture system and VITEK 2 automated identification system were used for bacterial culture and identi-fication.Antimicrobial susceptibility testing and detection of extended-spectrum β-lactamases (ESBLs)-producing strains were performed by Kirby-Bauer method.Results From 2009 to 2011 ,a total of 235 strains of E.coli were isolated from patients with bloodstream infection,90 (38.30%)of which were ESBLs positive strains.The resistant rates of ESBLs-producing strains to ampicillin,cefotaxime and ceftriaxone were all 100%,but susceptibility rate to imi-penem/cilastatin and meropenem were all 100%,to cefmetazole and amikacin were >90%.The resistant rate of non-ESBLs-producing strains to ampicillin was the highest (70.63%),susceptibility rate to imipenem/cilastatin and meropenem were both 100%,to amikacin,cefotaxime,and cefmetazole were all >95%.The resistant rate of ES-BLs-producing strains was significantly higher than that of the non-ESBLs-producing strains.Ofβ-lactamase inhibi-tor,only susceptibility rate of ESBLs-producing E.coli to cefoperazone/sulbactam was>90%,susceptibility rates to piperacillin/tazobactam and ticarcillin/clavulanate were both<80%.Conclusion Antimicrobial resistant rate of ESBLs-producing strains causing bloodstream infection is high,individualized treatment strategies should be made according to antimicrobial resistance of bacteria causing infection in patients.