Abstract
Randomly selected strains of .beta.-lactamase-negative and .beta.-lactamase-positive N. gonorrhoeae were tested by an agar dilution method for susceptibility to rosamicin, josamycin, erythromycin, clindamycin and penicillin G. Rosamicin was more active than erythromycin, which was more active than josamycin or clindamycin; the latter 2 were similar in their activity. The susceptibility to the macrolide antibiotics and clindamycin was independent of .beta.-lactamase production, but the penicillin minimal inhibitory concentrations were higher in the .beta.-lactamase-positive group because of the enzyme.