Filter-Passing Bacteria in Polluted Water

References to epidemics of gastro-enteritis attributable to polluted drinking water are numerous in the literature. Usually these outbreaks are followed by cases of typhoid fever; occasionally they consist only of acute intestinal distress without the subsequent development of cases of typhoid fever. A series of such epidemics in the Ohio River valley was investigated recently by Veldee. 1 He stated, “There is no epidemiological evidence to show that the ailment was produced by a viable organism contained in the water supply, unless we are to assume the sudden appearance of some bacterium or virus whose presence was not indicated by the established methods of water analysis.”

The possibility of the presence of some such microorganism in sewage-contaminated water was investigated. This report concerns the isolation and preliminary study of a form of viable organism from polluted river water, the filtrates of which were apparently sterile when tested by ordinary bacteriological methods.

A sample was taken from the Chicago River at a point where it was heavily polluted with domestic sewage. After filtration through paper, the water was filtered through a tested Berkefeld N filter and the filtrate collected aseptically. Cultures of this filtrate yielded no growth in solid or liquid media. Serial plating of the filtrate was begun, using the Hauduroy technique 2 as modified in this laboratory. 3 The method consists essentially of surface inoculation of litmus lactose agar plates, incubation for 48 hours, and inoculation of subsequent plates with the washings from the surface of the preceding plate. The inoculations are confined to a square area in the center of the plates, and the capillary pipettes and broth to be used in the operation are sterilized by autoclaving. Three series of plates were used; the first plate of each series was inoculated with a different amount of river water filtrate.