PREVALENCE OF NEISSERIA-MENINGITIDIS RELATIVELY RESISTANT TO PENICILLIN IN THE UNITED-STATES, 1991

To estimate the prevalence of Neisseria meningitidis relatively resist ant to penicillin in the United States, antimicrobial susceptibility t esting was performed on all US meningococcal isolates submitted to the Centers for Disease Control and Prevention in 1991, including isolate s identified through population-based surveillance for invasive mening ococcal disease in selected areas of the United States. Three of the 1 00 isolates tested had MICs of penicillin of 0.125 mu g/mL. All were s erogroup B, beta-lactamase-negative, and unique by multilocus enzyme e lectrophoresis subtyping. None of the 3 patients had been treated sole ly with penicillin; all recovered completely. About 4% of the isolates obtained from the population-based surveillance system were relativel y penicillin-resistant. Given the low prevalence and uncertain clinica l significance of infection with these organisms, routine susceptibili ty testing of meningococcal isolates is not indicated at this time; ho wever, continued surveillance is necessary to monitor trends in antimi crobial susceptibility of meningococci in the United States.