Susceptibility Patterns of ESBL Positive Uropathogenic Escherichia coli to CLSI Recommended Group Drugs for Enterobacteriaceae

Abstract

Bacterial pathogens causing acute infections are increasingly exhibiting resistance to the commonly used antibiotics and have thus become a great threat to public health. The failure of empirical therapy is frequently observed, even in community-acquired urinary tract infections. We, therefore, conducted a study in 2009-10 to find out what proportion of urinary tract infections with Escherichia coli were caused by ESBL producers, the assessment susceptibility pattern of ESBL positive and negative isolates to antibiotics and correlate them with possible risk factors to assist empirical decision making. Antimicrobial susceptibility testing was performed for CLSI recommended drugs Enterobacteriaceae by Kirby-Bauer disk diffusion method. Of the 404 E. coli isolates, 174 (43%) were confirmed as ESBL producers whereas 230 (56.9%) E. coli isolates were non-ESBL producers. The rate of resistance for Ciprofloxacin was 96.6% in ESBL positive E. coli isolates and 62.7% in ESBL negative E. coli isolates. Respective values were: for Levofloxacin (98%) and (66%), for Ofloxacin and Norfloxacin (92%) and (56%), (66%), for Tetracycline (94%) and (65%), for Trimethoprim-sulfamethoxazole (76.3) and (52%), Tobramycin (72%) and(44%), for Gentamycin (60%) and 44% in community acquired urinary infection caused by E. coli isolates showing high prevalence of ESBL more than 43% isolates. ESBL positive E. coli isolates exhibited high resistance to CLSI recommended antimicrobial agents when compared to non-ESBL E. coli isolates. ESBL producers are serious threat to public health necessitating continuous surveillance and use of appropriate screening tests for laboratory detection to control the further spread of resistance.