Aeromonas hydrophila in chlorinated water supplies.

Methods for the isolation and enumeration of Aeromonas hydrophila in water supplies are described. Examination of 286 chlorinated samples collected between July and October showed that 19% of otherwise uncontaminated waters contained Aerom. hydrophila, rising to 71% of those from which Escherichia coli was isolated. The isolation rate during January and February was only 7% for all samples. On the basis of these results, tap water is a likely source of the aeromonads found in human intestinal flora.