Antibiotic-resistant bacteria in drinking water

Publisher Website
Google Scholar
Abstract
Drinking waters were analyzed from 7 communities for multiply antibiotic-resistant (MAR) bacteria (bacteria resistant to 2 or more antibiotics) and the MAR bacterial isolates obtained were screened against 5 antibiotics by replica plating. Overall, 33.9% of 2653 standard plate count bacteria from treated drinking waters were MAR. Two different raw water supplies for 2 communities carried MAR standard plate count bacteria at frequencies of 20.4 and 18.6%; 36.7 and 67.8% of the standard plate count populations from sites within the repective distribution systems were MAR. Isolate identification revealed that MAR gram-positive cocci (Staphylococcus) and MAR gram-negative, nonfermentaive rods (Pseudomonas, Alcaligenes, Moraxella-like group M and Acinetobacter) were more common in drinking waters than in untreated source waters. Site-to-site variations in generic types and differences in the incidences of MAR organisms indicated that shedding of MAR bacteria living in pipelines may have contributed to the MAR populations in tap water. The treatment of raw water and its subsequent distribution apparently select for standard plate count bacteria exhibiting the MAR phenotype.