Background and objectives: Erythromycin is a recommended treatment for penicillin-allergic pregnant women with gonorrhea, and azithromycin has been suggested as therapy for coexisting gonococcal and chlamydial infections. Although gonococcal resistance to erythromycin is not uncommon, decreased resistance to azithromycin is rare. A clinical isolate of Neisseria gonorrhoeae with in vitro resistance to erythromycin and decreased susceptibility to azithromycin is reported.
Study design: This is a case report.
Results: Antimicrobial susceptibility testing of a clinical isolate of N. gonorrhoeae revealed a minimal inhibitory concentration (MIC) of 2 micrograms/ml to azithromycin and 32 micrograms/ml to erythromycin. Five hundred other urethral isolates were tested, resulting in an MIC for erythromycin ranging from 0.015 to 2 micrograms/ml. The range for azithromycin was 0.015 to 0.5 micrograms/ml. There was a strong correlation between erythromycin and azithromycin MICs (r = 0.73; P < 0.0001).
Conclusions: Continued national monitoring is needed to detect the appearance and early dissemination of new types of gonococcal resistance.