The pathogenicity of environmental campylobacters--a human volunteer experiment.

Three human volunteer experiments were performed in which river water expected to contain campylobacter organisms was ingested. Despite the ingestion of over 44,000 organisms in one experiment, the subject did not suffer any symptoms, nor were campylobacter organisms excreted, nor was an antibody response to the ingested strains detected. The campylobacter organisms ingested resembled Campylobacter jejuni on colonial and microscopic morphology but were hippurate negative, and were distinct from C. coli. These environmental campylobacter strains appear to be non-pathogenic, however they may be mistaken for C. jejuni or C. coli if they are not fully identified.