Identification of Pathogenic Bacteria in Water Samples in the Kathmandu Valley, Nepal, Using DNA Microarray Analysis

摘要

A high demand for livestock products led to discharge of feces into the environment. Fecal pathogens, when discharged into the water environment, can survive for a long period, serving as a potential source and reservoir of waterborne diseases. This study investigated the presence of pathogenic bacteria using a DNA microarray targeting 941 pathogenic bacterial species/groups in water samples in the Kathmandu Valley, Nepal. Sixteen water samples were collected from 13 shallow dug wells, a deep tube well, a spring, and a river. The number of pathogenic bacterial species/groups detected in each of the 16 water samples tested ranged from 31 to 213. Thirty biosafety level (BSL) 2 pathogens and 1 BSL 3 pathogen were detected in >70% of the water samples. Waterborne pathogenic bacteria that could be transmitted through the fecal-oral route were identified, whereby Vibrio cholerae, Klebsiella spp., and Salmonella enterica serovars were detected in 63%, 38%, and 31% of the water samples tested, respectively. Detection of various waterborne pathogenic bacteria in groundwater and river water samples indicates that there is a serious risk of pathogen infection through consumption of contaminated groundwater.