Incidence of multiple potentially pathogenic bacteria in tap water from different restaurants in Dhaka city, Bangladesh

This study was conducted to determine the presence of potentially pathogenic bacteria in 20 tap water sources used in different restaurants in Dhaka city. A questionnaire was used to determine the aesthetic quality and extent of use of these sources. In the microbiological examination, all samples were found to be contaminated with coliforms. Although fecal coliforms could not be detected in samples 5, 12 and 16, these samples were found to be contaminated with coliforms and pathogenic bacteria such as, Vibrio spp., Shigella spp. and Salmonella spp. Concentrations of total heterotrophic bacteria were beyond the recommendation suggested by the World Health Organization (1.2 × 10⁴ and 5.4 × 10⁴ cfu/ml). These contaminated waters pose threats to the health of the consumers. It is possible that deep tube well water is cross contaminated from underground sewerage lines which require repair and amendment of water supply system.