[The resistance of Francisella tularensis to the bactericidal action of normal serum as a criterion for evaluating the virulence of the bacterium].

The study of the sensitivity of F. tularensis to the bactericidal action of normal serum (NS) revealed that all virulent cultures were resistant, while avirulent cultures were highly sensitive to NS. The synthesis of R-lipopolysaccharide (LPS) by capsule-deficient (Cap-) clones or the synthesis of S-LPS by capsule-defective (Cap+/-) clones of the avirulent phenotype of these bacteria had no influence on the sensitivity of these forms to NS, but ensured longer survival of Cap+/- variants in the serum in comparison with Cap- cells.

[Effect of subinhibitory concentrations of antibiotics on catalase activity of plague microbes].

It was shown that the presence of subinhibitory concentrations of ampicillin, cefotaxime or gentamicin in the cultivation medium had a marked inhibitory effect on the catalase activity of plague microbe. The effect depended on the characteristic features of plague microbe strains and the incubation temperature. When the cells of a virulent strain of the plague microbe Y.

[Pseudotuberculosis in the Krasnodar Territory. The clinico-epidemiological characteristics of its morbidity and the biological properties of its strains].

Group cases of pseudotuberculosis, first registered at health-restoring institutions of the health resort of Gelendzhik (the Krasnodar Territory), are described. The etiology of these cases of the disease was established on the basis of clinico-epidemiological data, specific seroconversion in 66% of the examined patients and the isolation of Yersinia pseudotuberculosis strains from the feces of four patients. The combination of signs observed in the isolated strains, viz.