Copyright C) 1994, American Society for Microbiology Ribotyping as an Additional Molecular Marker for Studying

The molecular method of ribotyping was used as an additional epidemiological marker to study the epidemic strains of Neisseria meningitidis serogroup B, referred to as the ET-5 complex, responsible for the epidemic which occurred in greater Sao Paulo, Brazil. Ribotyping analysis of these strains showed only a single rRNA gene restriction pattern (Rbl), obtained with ClaI restriction enzyme. This method, as well as multilocus enzyme electrophoresis, provided useful information about the clonal characteristics of the N. meningitidis serogroup B strains isolated during this epidemic. The N. meningitidis serogroup B isolates obtained from epidemics which occurred in Norway, Chile, and Cuba also demonstrated the same pattern (Rbl). Ribotyping was a procedure which could be applied to a large number of isolates and was felt to be appropriate for routine use in laboratories, especially because of the convenience of using nonradioactive probes. Meningococcal disease (MD) is a significant cause of mor-tality and morbidity throughout the world (15, 20). Serogroup B is the most common cause of sporadic MD in developed countries (17, 18), and until recently, no effective vaccine was available for prevention of infection with this organism (11, 21). The incidence of MD in Brazil has been monitored sinc