Isolation of moderately penicillin-susceptible strains of Neisseria meningitidis in Argentina.

Four strains that were moderately susceptible to penicillin and/or ampicillin were found among 54 consecutive isolates of meningococci recovered from patients in one pediatric hospital in Argentina from October 1991 to December 1992. Disk diffusion tests performed with 2 U of penicillin failed to detect one strain. These findings suggest that attention should be paid to changes in the susceptibility patterns of meningococci in order to anticipate therapeutic failures in the future.