Toxigenic Vibrio cholerae from environmental sources associated with the cholera outbreak after ‘AILA’ cyclone in West Bengal, India

Abstract

West Bengal experienced a devastating storm named 'AILA' in its coastal and southern districts. We attempted to understand the transmission dynamics emphasizing on potable water to detect the presence of toxigenic strains of Vibrio cholerae, followed by the natural devastation. A total of 33 water samples (from tap, tube well and ponds) were analysed. From them, 11 (33.3%) samples were found to be contaminated with V. cholerae, among which 5 (45%) isolates were V. cholerae O1 biotype Ogawa. Antibiogram profile reveals that most of the V. cholerae O1 isolates were highly sensitive against fluroquinolone group of antibiotics, but less sensitive against cefuroxime (50%), cefotaxime (40.9%), ceftriaxone (38.63%), trimethoprim (37.3%), streptomycin (29.2%) and furazolidon (4.54%). Three (36%) V. cholerae isolates were found to be ctxB positive (2 ctxB classical). Potable water plays a crucial role in cholera transmission. Natural disasters like the reported one aided with feacal-oral contamination enhance the possibilities of drinking water contamination. The application of the modified technique, making use of the enrichment subsequently followed by culture and PCR, will help us to detect the presence of toxigenic V. cholerae contamination in different aquatic environment. Moreover, natural extremes have a direct role in increase of salinity level, followed by higher predominance of V. cholerae along with their toxicity development in terms of genetic modification.