RESUMO
Use of the precipitation and hemagglutination inhibition tests to determine the serological group of 114 meningococcus strains which cannot be grouped by agglutination slide permitted to establish the serological group of 56% of the strains, this pointing to the greater diagnostic value of these tests. Nevertheless, 70% of 307 strains isolated from carriers could not be referred to any of the determinable groups (A, C, X, Y, and Z). Strains (417) isolated from the cerebrospinal fluid of patients with meningitis were grouped depending on the epidemic curve: only half of the cultures could be classified in sporadic cases, but from 80 to 100% of the strains were classified at the "peak" of the meningitis incidence rise. This rise was connected with increase of the incidence of cases caused by meningococcus, group A; at the decline these strains were eliminated, and cases due to the rarely encountered serological groups and nongrouping strains occurred. Marking meningococc by serological groups proved to be of no use for detection of epidemiological relations between the infected persons.
