Osaulenko O V, Maramovich A S, Veĭde A A, Vertiev Iu V, Shaginian I A
Zh Mikrobiol Epidemiol Immunobiol. 1990 Jan(1):9-13.
As the result of the study of toxin formation in 165 V. eltor strains having different virulence, most of the virulent cultures have shown stable toxin production, though 5-10% of their colonies have proved to be nontoxigenic. In faintly virulent strains toxin production was found to be unstable, which is indicative of the heterogeneity of their population composition as regards their capacity for toxin formation. The population of avirulent strains consists mainly of nontoxigenic clones (95.7%).