Detection of tetracycline resistant E. coli and Salmonella spp. in sewage, river, pond and swimming pool in Mymensingh, Bangladesh

Antibiotic resistant bacteria and resistance genes in the environment are major health problem globally. The present study was undertaken to detect antibiotic resistant Escherichia coli and Salmonella spp. in sewage, river, pond and swimming pool. Emphasis was given on tetracycline resistant phenotype and genotype, since, tetracycline is a widely used antibiotics. Isolation and identification of antibiotic resistant E. coli and Salmonella spp. were based on morphology, staining, cultural, and biochemical properties, disk diffusion test and PCR. A total of 47 samples were collected from Mymensingh, Bangladesh. Among the 47 samples, 36 (76.59%) were found positive for E. coli and 42 (89.36%) for Salmonella spp. Phenotypically, all isolates were found resistant to tetracycline as revealed by disk diffusion test. Isolated E. coli were resistant to chloramphenicol (5.5%), streptomycin (16.6%) and ampicillin (97.2%) while Salmonella spp. to chloramphenicol (07.1%), ciprofloxacin (07.1%), streptomycin (19.1%) and ampicillin (100%). All bacterial isolates were sensitive to gentamycin. PCR result showed that 77.77 and 80.95% phenotypically tetracycline resistant E. coli and Salmonella spp. were positive for tetA gene. From this study it is concluded that tetracycline resistant E. coli and Salmonella spp. widely present in sewage, river, pond and swimming pool water are of great public health concern.