[The phenotypic heterogeneity of meningococcal strains by their serogroup trait].
It is shown that heterogeneity of meningococci of the outlined serogroups is formed due to appearance of nonagglutinable individuals in subpopulations but heterogeneity of polyagglutinable strains is characterized by incorporation not only of cross-reacting cells, but also microcommunities of each separate group which make a total feature. Serologically inactive strains either may be homogeneous or may form variants with low (to 20%) and high (to 44%) specific weight of agglutinable colonies. Strains in the centres embrace different concentrations of microcommunities which are identical by their serogroup properties to subpopulations of the meningitis pathogen.