Persistence of PCR-detectable Bacteroides distasonis from human feces in river water.

To evaluate the persistence of PCR-detectable Bacteroides distasonis in surface water, whole human feces were dispersed into water from the Ohio River and incubated in flasks in the laboratory or in diffusion chambers in situ. Duplicate samples were taken daily, and material that pelleted at 16,000 x g was assayed by PCR. Persistence of PCR-detectable DNA from this anaerobe depended upon temperature and predation, two of the factors shown by others to influence the survival of aerobic bacteria detected by culture. B. distasonis was detected by PCR for at least 2 weeks at 4 degrees C but for only 4 to 5 days at 14 degrees C, 1 to 2 days at 24 degrees C, and 1 day at 30 degrees C. In filtered water or in the presence of cycloheximide, a eukaryotic inhibitor, persistence at 24 degrees C was extended by at least a week.