Antimicrobial susceptibilities of Neisseria gonorrhoeae strains representing five distinct resistance phenotypes.

The susceptibilities of 109 strains of Neisseria gonorrhoeae to penicillin G, tetracycline, amoxicillin-clavulanic acid, cefotetan, cefoxitin, ceftriaxone, ciprofloxacin, and fleroxacin were determined. The activities of cefmetazole, cefuroxime, cefixime, and ofloxacin were also determined against 62 of these strains. Strains represented penicillin-susceptible (Pen(s)) N. gonorrhoeae; penicillinase-producing N. gonorrhoeae (PPNG) possessing 2.9-, 3.05-, 3.2-, or 4.4-MDa beta-lactamase plasmids; strains with high-level, plasmid-mediated tetracycline resistance (TRNG); strains with plasmid-mediated resistance to penicillin and tetracycline; and strains with chromosomally mediated resistance to penicillin and tetracycline (CMRNG). Ceftriaxone, cefixime, and ciprofloxacin were the most active agents tested against all strains. Pen(s), TRNG, and PPNG strains possessing a 3.2-MDa beta-lactamase plasmid were more susceptible to amoxicillin-clavulanic acid, extended- and broad-spectrum cephalosporins, and quinolones than were either PPNG strains possessing a 2.9-, a 3.05-, or a 4.4-MDa beta-lactamase plasmid or CMRNG strains.