Epidemic spread of subgroup III of Neisseria meningitidis serogroup A to South Africa in 1996.

A total of 111 strains of Neisseria meningitidis isolated during a meningitis outbreak in Johannesburg, South Africa, in 1996 were analyzed by serogrouping, arbitrarily primed polymerase chain reaction analysis, ribotyping, and multilocus enzyme electrophoresis. Nineteen different clusters were identified, and typing patterns for the three techniques were comparable. Of the 111 strains analyzed, 55 (49.5%) belonged to the serogroup A clone complex designated internationally as subgroup I-1. The second largest cluster included 15 isolates (13.5%) that were identified as belonging to the pandemic clone III-1. A number of unrelated strains were also encountered. Our study provides the first documented evidence of the presence of clone III-1 in South Africa and indicates the continued spread of this clone well outside the African meningitis belt.