Microbiological quality assessment (including antibiogram and threat assessment) of bottled water

Water pollution is a major global problem that has been the leading cause of morbidity and mortality. This study was carried out to assess the microbiological quality of popular domestic brands of bottled water available in the Kathmandu Valley in Nepal. For the study of bottled water, a total of 50 samples each of different volumes (20 and 1 L) were selected. The samples were processed at the Microbiology laboratory at St. Xavier's College, Maitighar, Kathmandu. The microbiological assessments were performed as per the methods described in the American Public Health Association, 2005. Out of 100 samples, 48% of samples were found to be contaminated with total coliform. Escherichia coli was the predominant strain among the coliforms. Multidrug-resistant E. coli, Enterobacter aerogenes, and Pseudomonas aeruginosa were isolated from the 48 bottled water. Treat assessment test revealed that 88.23% of the isolated E. coli produced β hemolytic colonies, while 11.77% did not show hemolytic colonies, 100% E. aerogenes colonies were not able to develop hemolytic colonies and 100%, P. aeruginosa colonies gave β hemolytic colonies, respectively. Chi-square test shows that there is a significant association (p ≤ .05) between fecal coliform and volume of the vessel (i.e., 20 and 1 L), bottle type (i.e., unscratched and undented and scratched and/or dented), season (i.e., monsoon and postmonsoon), and total coliform. Chi-square test shows that there is no significant (p > .05) association between Pseudomonas spp and season (i.e., monsoon and postmonsoon). Out of 100 samples, 48% of samples were found to be contaminated with total coliform. Microorganisms survive in bottled water as they have many nutrients required for the microorganism in ionic form. Surveillance is lacking by the license-providing organizations followed by governmental organizations.