Identification of class 1 integrons-associated gene cassettes in Escherichia coli isolated from Varanus spp. in Indonesia

1Department of Biology, Faculty of Science and Mathematics, IUC Biotechnology, Bogor Agricultural University; 3South East Asian Regional Centre for Tropical Biology (SEAMEO-BIOTROP), Bogor, Indonesia; 2Institut für Tierzucht, Bundesforschungsanstalt für Landwirtschaft (FAL), Höltystr. 10, 31535 Neustadt-Mariensee, Germany; 4Natural Sciences UNESCO, 1 rue Miollis, 75732 Paris, Cedex 15, France Sir, Escherichia coli isolates play a major role in the horizontal gene transfer of resistance genes located on mobile genetic elements between intestinal bacteria of different species and genera.1 While data on antimicrobial resistance in E. coli are commonly obtained from clinical isolates of humans, food-producing animals or pets, little is known about the antimicrobial resistance of E. coli from free-living animals in remote geographical areas. In this study, we investigated 28 E. coli isolates obtained from faecal samples of monitor lizards (Varanus spp.) for the presence of antimicrobial resistance-mediating gene cassettes located in class 1 integrons. The 28 E. coli isolates were obtained from free-living individual animals of different monitor lizard species captured alive in various regions in Indonesia. Antimicrobial resistance testing by disc diffusion was performed and evaluated according to the NCCLS document M31-A.2 Of the 28 E. coli isolates, 21 proved to be resistant to tetracycline (75.0%), 20 to streptomycin (71.4%), 19 to sulfamethoxazole (67.9%), 18 to ampicillin (64.3%), seven to kanamycin or chloramphenicol (25.0%) and five to gentamicin or trimethoprim (17.9%). Many of the E. coli isolates showed multiresistance to the antimicrobial agents tested. In this regard, E. coli from the intestinal flora of lizards did not differ distinctly from the E. coli isolates commonly found in mammals where they represented the main carrier of antimicrobial resistance in the intestinal flora.3