Integrons and multidrug resistance among Escherichia coli causing community-acquired urinary tract infection in southern India

Abstract

Antimicrobial resistance genes are often clustered in integrons, genetic elements capable of recombination. There is a paucity of data on the prevalence and role of integrons from community-acquired infections in developing countries where resistance to co-trimoxazole is high. We determined the prevalence of integrons among Escherichia coli causing community-acquired urinary tract infection (UTI). Consecutive isolates of E. coli obtained from UTI of pregnant women at the Christian Medical College Hospital, Vellore, India, during 2002 were included. All isolates were tested for susceptibility to 16 antimicrobials using the disc diffusion method and for integrons of classes 1 and 2 by PCR. Of the 58 isolates tested, 28 (48.3%) were resistant to co-trimoxazole and trimethoprim. All these isolates carried integrons. Three additional isolates were sulfonamide resistant but integron negative. Class 1 integrons were present in 21 (36.2%) isolates. Resistance to ampicillin (p=0.000), nalidixic acid (p=0.001), chloramphenicol (p=0.02), tetracycline (p=0.004) and gentamicin (p=0.02) was significantly more common in isolates with integrons. DNA sequencing of two isolates with integrons showed the presence of aadA, dfr1 and dfr7 genes. This study demonstrated that integrons are widely prevalent in India and that they might play a role in multidrug resistance in E. coli from community-acquired UTI.