Analysis of drug susceptibility and risk factors for drug resistance of Escherichia coli in elderly patients with urinary tract infection

Abstract

Objective To investigate the risk factors for drug resistance of urinary tract infections-causing Escherichia coli producing extended spectrum beta-Lactamases (ESBLs) in elderly people (≥65 years old), in order to provide evidence for rational use of antibiotics in clinic. Methods Clinical data of elderly patients diagnosed as urinary tract infections in Beijing Chao-Yang Hospital from January 2016 to December 2017 were retrospectively analyzed. According to whether ESBLs were produced by Escherichia coli isolated from urine samples, the patients were divided into the ESBLs-producing E. Coli group (ESBLs group) and the control group. Single factor analysis was performed by Chi-square test.Logistic regression analysis was used to analyze the risk factors for ESBLs-producing Escherichia coli infections in urinary tract on the basis of statistical significance. Results A total of 452 strains of Escherichia coli were isolated, including 253 strains (55.97%) producing ESBLs, and 199 strains (44.03%) not producing ESBLs. The ureteral calculi (OR=2.675, 95%CI: 1.129-6.341), urinary obstructive diseases (≥ 2 kinds) (OR=8.680, 95%CI: 2.508-30.040), indwelling catheters (OR=5.762, 95%CI: 2.698-12.155), antibiotic treatment more than 2 weeks for urinary tract infections within one year (OR=3.461, 95%CI: 1.766-6.784) were independent risk factors for ESBLs-producing Escherichia coli urinary tract infections. The incidence rate of Escherichia coli resistance to various antibiotics was higher in elderly patients with urinary tract infection than in non-elderly patients. Conclusions Escherichia coli producing ESBLs can be easily isolated from elderly patients with urinary tract obstructive diseases, indwelling catheters and repeated long-term administration of broad-spectrum antibiotics. The proportion of ESBLs Escherichia coli-caused urinary tract infections is higher in elderly patients. Thereby, carbapenems or piperacillin/tazobactam is the reasonable antibiotics. Ampicillin, piperacillin, levofloxacin and ciprofloxacin should not be the first choice for the treatment of urinary tract infections in the elderly. Key words: Urinary tract infections; Escherichia coli infections; Drug tolerance