Identification of an Epidemic Strain of Neisseria meningitidis by Bacteriocin Typing

Meningococci of serologic groups Band C can be subclassified on the basis of their sensitivity to bacteriocins produced by indicator strains. Among organisms of group C that were studied, 11 types of meningocin were identified, while 32 distinct patterns of sensitivity to meningocin were recognized among group B isolates. Production of and sensitivity to meningocin appear to be independent of serologic classification and sensitivity to sulfonamides. However, by consideration of all of these characteristics together, precise epidemiologic studies are possible. For example, it was shown that an outbreak of meningococcal disease among military recruits was caused by a sulfisoxazole-resistant group C meningococcus of a specific meningocin type. This strain was not generally encountered among recruits entering training, but when it was introduced into closed populations, it colonized widely and caused disease in three of 46 men infected. The ability to separate strains of Neisseria menin-gitidis into broad groups on the basis of agglutina-tion reactions in immune serum has provided