Evaluation of integrons classes 1–3 in extended spectrum beta-lactamases and multi drug resistant Escherichia coli isolates in the North of Iran

Abstract

Antimicrobial resistance of Escherichia coli is an increasing problem that makes treatment complicated. Integrons may help bacteria to acquire novel combinations of resistance genes which can play an important role in antibiotic resistance. This study aimed to determine the prevalence of class I-III integrons in clinical isolates of E. coli and their probable relation to multi-drug resistant (MDR) and extended-spectrum beta-lactamases (ESBLs). During the eight months from November 2014 to July 2015, plasmid DNA of 193 E. coli isolates was extracted after determining their resistance pattern and ESBL production by disk diffusion method. To detect the presence of class I–III integrons polymerase chain reaction (PCR) was performed for all isolates. Among 193 isolates, 37.3% of isolates were ESBL-producing. Also, 79.3% and 13% were positive for intl I and intl II genes, respectively; while intl III gene was not detected. Overall, 65.9% and 81.8% of isolates were MDR which isolated from urinary and non-urinary samples respectively. Our results indicated a negative association between the presence of class I and II integrons and resistance to some of the studied antibiotics. The contrary results may be due to empty or nonfunctional integrons or presence of gene cassettes on prophages or transposons instead of integrons.