In vitro activity of rosamicin, josamycin, erythromycin, and clindamycin against beta-lactamase-nagative and beta-lactamase-positive strains of Neisseria gonorrhoeae.

Randomly selected strains of beta-lactamase-negative and beta-lactamase-positive Neisseria 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 two 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.