Drug resistance and clinical characteristics of extended-spectrumβ-lactamase-producing Escherichia coli causing bloodstream infections

HE Wei-ping; DENG Feng-ying; BAO Chun-mei; JI Ying-jie; CUI En-bo; ZHANG Wen-jin; Fan Zhen-ping; QU Fen

Abstract：Objective To investigate the drug resistance and clinical characteristics of extended-spectrum β-lactamases (ESBLs)-producing Escherichia coli causing bloodstream infections, so as to provide evidence for rational use of antibiotics in clinical practice.Methods BacT/Alert 3D automated blood culture system was used for bacterial culture, and Vitek Ⅱ automated identification system for bacterial identification. ESBLs detection and confirmation and drug susceptibility were tested by Kirby-Bauer method. Clini-cal characteristics of patients with ESBLs-producing E. coli were analyzed. Results A total 235 strains of E. coli were isolated from patients with bloodstream infections, with 90 (38.3%) producing ESBLs. All of ESBLs-producing strains were resistant to ampicillin, cefotaxime and ceftriaxone,and susceptible to imipenem/cilastin. The susceptibility rates to meropenem, cefmetazole and amikacin exceeded 90% , and the resistance rates to β -lactamase inhibitors including cefoperazone/sulbactum, ticarcillin/clavulanate and piperacillin/tazobactum were 6.7%, 29.2% and 34.4%, respectively. Patients aged above 50 years old accounted for 57.8%. The onset of bloodstream infections occurred within 1 week after admission in 58.9% of the patients, and spontaneous bacterial peritonitis causing bloodstream infections was found in 46.7% of the patients. Severe complications were found in 35 patients, of whom 20 (57.1%) failed the treatment or died. Conclusions Due to the severity and poor prognosis of bloodstream infectionｓ caused by ESBLs-producing E. Coli, patients' condition,clinical characteristics and drug resistance to bacteria should be taken into consideration in clinical use of drugs, so as to make individualized treatment strategies.