Report on an intrafamiliar outbreak of Campylobacter enteritis.

An intrafamiliar campylobacter enteritis outbreak is described. From stools of three adults and two children, 5 Campylobacter jejuni strains resistant to erythromycin, lincomycin, and tetracycline, were isolated. From the sixth member of the family, a boy, a susceptible strain was isolated. Serological responses, measured using a serum bactericidal assay, against autologous and heterologous campylobacters have shown that one strain only, the resistant one, caused the outbreak. The source of infection was unknown.