Isolation of enterotoxigenic Vibrio cholerae non-01 from the Buriganga river and two ponds of Dhaka, Bangladesh

Abstract

Vibrio cholerae 01 is usually considered the most toxigenic member of the Vibrionaceae and V. cholerae non-01 isolated from the environment is non-toxigenic. In our survey of the pollution of some aquatic environments in and around Dhaka, Bangladesh, we wanted to investigate the toxigenicity of V. cholerae non-01 isolated from water and sediment samples of the Buriganga river and two ponds in Dhaka, in the rabbit ileal loop (RIL) model. Fluid accumulation was induced by 18 of 28 live cultures and five of 18 cell-free culture filtrates in RIL. Seven of ten V. cholerae non-01 which failed to induce fluid in RIL were subjected to repeated passage in rabbit gut. Within two consecutive passages, all the strains could induce fluid in rabbit gut. Both toxigenic and non-toxigenic strains were uniformly sensitive to chloramphenicol and gentamicin but resistant to neomycin, novobiocin, polymyxin-B, streptomycin and vancomycin. Tetracycline sensitivity was found among eight of 17 toxigenic and six of 12 non-toxigenic strains. Sensitivity to trimethoprime-sulfa-methoxazole was noted among seven of 17 toxigenic and six of 12 non-toxigenic strains. Occurrence of enterotoxigenic and drug-resistant V. cholerae non-01 in the surface water is a public health hazard.