Abstract

Penicillinase production and minimum inhibitory concentrations (MICs) of penicillin G, amoxycillin, doxycycline, and spectinomycin were studied for 155 gonococcal strains isolated in Fukuoka, Japan, between April and December 1981. Of 155 isolates, 25 (16.1%) strains were identified as penicillinase-producing Neisseria gonorrhoeae (PPNG) by a rapid iodometric test. The antibiotic sensitivity of 130 penicillinase-negative (non-PPNG) and 25 PPNG strains was compared. The mean MIC of penicillin G for non-PPNG strains was 0.65 microgram/ml. Twenty-five PPNG strains had MICs of penicillin G between 6.25 and greater than 100 micrograms/ml. The susceptibility to amoxycillin and doxycycline of PPNG strains was significantly lower than that of non-PPNG strains. All the strains proved to be sensitive to spectinomycin. The MICs of four antibiotics for non-PPNG strains were significantly correlated.