Induction of phenotypically determined resistance of neisseria gonorrhoeae to human serum by sera from patients with gonorrhoea.

Some human sera contain factors which induce in gonococci a resistance to killing by fresh human sera. Individuals with serum containing these factors might possibly be more prone to gonorrhoea. A survey of the sera of 50 female and 50 male patients with gonorrhoea for resistance-inducing capacity showed, however, that the proportions of positive sera (24% for women, 28% for men) were not significantly different from those (16% for women, 24% for men) from an equal number of controls. Examination of the results, however, in relation to the type of gonococcal infection showed that: (a) the sera of 15 female patients with complicated (salpingitis) or successive infection or both did not induce resistance (statistically significant); (b) a greater proportion (34%) of sera from female patients with single gonococcal infections induced higher gonococcal resistance than for control sera (16%) (at the borderline of statistical significance); and (c) a greater proportion (38%) of sera from the few male patients with successive infections induced higher resistance than for control sera (24%) (not statistically significant).