In vitro activities of ciprofloxacin, cefotaxime, ceftriaxone, chloramphenicol, and rifampin against fully susceptible and moderately penicillin-resistant Neisseria meningitidis.

Moderately penicillin-resistant Neisseria meningitidis was responsible for an outbreak of meningococcal disease in Saskatoon, Saskatchewan, Canada in 1993. We tested fully susceptible and moderately resistant strains of N. meningitidis against ciprofloxacin, cefotaxime, ceftriaxone, chloramphenicol, penicillin, and rifampin. Eighteen percent of the isolates were moderately resistant to penicillin (MIC > or = 0.06 microgram/ml) whereas susceptibility was 100% for the other agents tested.