Variations in the virulence, for pregnant guinea pigs, of campylobacters isolated from man.

Pregnant guinea pigs were used to compare the virulence of four human isolates of Campylobacter fetus ss. fetus and four of C. jejuni on the basis of their ability to cause abortion and bacteraemia. Of the four strains of C. fetus ss. fetus two produced abortion readily after intramuscular injection. The four C. jejuni isolates were, however, of comparatively low virulence and no differences between them were demonstrated. Some of the isolates differed in their ability to survive in vitro in human and guinea-pig serum. It is suggested that campylobacters vary in their virulence for man and that this may influence the outcome of infections. Guinea pigs may prove useful in studying the pathogenesis of systemic campylobacter infections.