Quantification of Arcobacter and its Virulence Genes in Environmental Water Samples in the Kathmandu Valley, Nepal

摘要

This study aimed to determine the quantitative occurrence of Arcobacter along with its 5 virulence genes (ciaB, cadF, mviN, pldA, and tlyA) in water samples. A total of 288 water samples were collected from deep tube wells (n = 33), rivers (n = 14), pond (n = 1), shallow dug wells (n = 165), shallow tube wells (n = 32), springs (n = 21), and stone spouts (n = 22), in the Kathmandu Valley, Nepal, in February-March and August 2016. Bacterial DNA was extracted from the water samples, which was subjected to quantitative PCR for Arcobacter and its virulence genes. Arcobacter was detected in 35% (100/288) of water samples tested, with concentrations ranging from 4.4 to 10.8 log copies/100 mL. Eighty-four (84%), 17 (17%), 19 (19%), 23 (23%), and 17 (17%) of the 100 Arcobacter-positive samples were also positive for ciaB, cadF, mviN, pldA, and tlyA, respectively. At least one virulence gene was detected in 87 samples. The presence of Arcobacter and its virulence genes in water samples shows persistence of pathogenic bacteria in the environment and suggests importance of regular monitoring of pathogens in the water sources.