Antibiotic Resistant Coliforms in Drinking Water of Kathmandu Valley

Abstract

Coliform in drinking water is of great importance due to its indicative value to faecal contamination. Antibiotic resistance and its dissemination in coliforms is a serious public health issue. The study was undertaken to describe drug resistant coliforms in the drinking water from different sources in Kathmandu valley. This study was conducted at Environmental Microbiology Laboratory of Central Department of Microbiology, from January to August 2011. A total of 66 water samples consisting 28 tap water, 24 well water and 14 stone spouts water were randomly collected from different location of Kathmandu valley, and subjected to microbiological analysis. Modified Kirby-Bauer Disc diffusion method was followed for antibiotic susceptibility test of coliform isolates. Temperature of all analysed water samples ranged from 10o C to 16 o C and pH ranged from 6.5 to 8.5. Higher number of stone spouts water samples 85% (n=12) were contaminated with coliforms followed by well water 79.2% (n=19) than tap water 60.7% (n=17). Similarly, the thermotolerant coliform growth was found in higher number of well water samples. 87.5% (n=21), followed by stone spouts water 71.4% (n=10) and tap water 67.9% (n=19). But no significant correlation was found between source and coliform (P>0.05), Thermotolerant coliform (P> 0.05). In this study 97 different isolates of organisms were identified as Escherichia coli 32% (n=31), Citrobacter spp 24.7% (n=24), Enterobacter spp 21.6% (n=21) and Klebsiella spp 18.6% (n=18) and Salmonella Typhi 3.1% (n=3). Higher MDR isolates were E. coli 92.3% (n=28), Citrobacter 62.5% (n=15), Klebsella 72.2% (n=13), Enterobacter spp 47.6% (10) and Salmonella spp 100% (n=3). The most of MDR were attributed to resistance towards Tetracycline and Amoxicillin. The water of different water sources were found polluted with total coliform and presence of MDR Gram negative bacteria were reported.