Abstract

It is believed that high antibiotic consumption and horizontal transfer of resistance genes are two major causes of antibiotic resistance in bacteria. To confirm or reject this belief, we studied the role of drug administration in antimicrobial resistance (AMR), prevalence of Class I and II integrons and integron-mediated resistance in Escherichia coli isolated from human and animal specimens. Recording demographic data, E. coli from different specimens including human, chicken, cattle and sheep was isolated followed by phenotypic antibiotic susceptibility testing and detection of Class I and II integrase genes. The correlation between integrons and resistance (P value) was evaluated using SPSS software. According to demographic records, chickens received the highest dose and variation of antibiotics. As expected, the most prevalent MDR strains and integrons were found in chicken strains. Chi square analysis showed a significant correlation between integrons and resistance pattern mostly in E. coli strains isolated from chicken rather than other specimens. Our survey confirmed that the use of antibiotics is strongly associated with the prevalence of antimicrobial resistance and integrons in commensal E. coli. Such results confirm that high doses of antibiotics and selection pressure may remove susceptible intestinal microorganisms followed by resistant ones.