[The differentiation of Bordetella (B.) bronchiseptica strains. 8. The protective behavior of B. bronchiseptica strains in mice in relation to the loss of K factors]. / Untersuchungen zur Differenzierung von Bordetella-(B.-)bronchiseptica-Stämmen. 8. Mitteilung: Untersuchungen zum protektiven Verhalten von B.-bronchiseptica-Stämmen bei Mäusen in Beziehung zum Verlust der K-Faktoren.

K factors are phase-dependent, instable antigen components of B. bronchiseptica. Loss of K factors was induced by passaging on 10% horse blood agar. All K factors were not simultaneously eliminated. Cultures obtained from various passages were checked on white mice by Lienotox testing and in protectivity experiments. Culturing of B. bronchiseptica on 10% horse blood agar in Phase I probably had an adverse impact on expression of virulence-dependent factors. K factor expression in B. bronchiseptica was found to depend on both phase condition and culturing medium.