Notes on the Relation between Coliforms and Enteric Pathogens

Abstract

The literature concerning the relative prevalence of coliforms and Eberthella typhosa in sewage and sewage-polluted waters and the quantitative data available on such prevalence have been presented as a ratio of E. typhosa per million coliforms at varying levels of typhoid fever morbidity. Evidence is presented to show that this ratio could be expected to remain constant through bact. reductions produced by natural purification processes approximating 99.9%. Data for 3 temp, ranges from about 5 to 25[degree]C are included. The theory that the minimum infectious dose of E. typhosa in man is a single bacterium, is presented. Based on this theory and the data presented it is estimated that only 1-2% of persons who ingest a single E. typhosa develop typhoid fever. These studies emphasize the basic value of the coliform test as an indicator of the possible presence of pathogens. They indicate also that a very real danger may exist when coliforms, in even moderately high cones., are present in ingested media. The factor of safety provided by the ratios given would, it is believed, take care of the usual fluctuations in the ratio of E. typhosa to coliforms provided the density of coliforms in ingested media be kept quite low.