Arun Jyothi Mathias, B. Sumitha, K.V. Deepa, C. Ramya, Deepashree G.H.M. and Smitha
Abstract
Heterotrophic bacteria, total conforms and two indicators of faecal contamination (faecal coliforms and faecal enterococci) as well as two types of pathogenic bacteria (Staphylococcus aureus and Pseudornonas aeruginosa) were enumerated from 32 drinking water samples from various residences and workplaces of Bangalore. Care was taken to include tap water, ground water, tank water and cooler water in the samples. Most of the water supplies were unsatisfactory as judged by Heterotrophic Plate Counts (HPC) of over 103/mL and the presence of Total coliforms (TC), Faecal Conforms (FC), Faecal Enterococci (FE) and Pseudornonas aeruginosa. Alarmingly the coliform contamination was greater in ground water than in tap water or stored water samples. 68% of the samples showed the presence of faecal enterococci while S. aureus was absent in all the samples tested. P. aeruginosa was prevalent in ground water and cooler water samples. Though the pH range was acceptable for drinking water samples, 80% samples exceeded the tolerable limits of total hardness. 64.2% of E.coli isolates tested were resistant to colistin while 78.5% of P.aeruginosa isolates were resistant to carbenicillin. Most of the Multiple Antibiofic Resistant (MAR) strains were from tap water. We were able to discern the dominant factors responsible for the contamination of water coolers and ground waters, but not in case of tap water.