Serotype and sulphonamide sensitivity of meningococci isolated from 1966 to 1971.

From 1966 to 1971, 298 cultures of meningococci from clinical material (cerebrospinal fluid or blood) were examined. Eighty-nine cultures were from the Manchester area and the remainder from other parts of England or Northern Ireland. Five per cent of strains were group A, 57% group B, and 31% group C; 6% were untypable. Eighteen strains (6%) had an MIC of 6.4 mug/ml or more of sodium sulphadiazine and 10 of these (3.5%) an MIC of 50 to 100 mug/ml. The incidence of sulphonamide resistance was higher in group A strains than in group B or group C strains.