[The biological properties of Salmonella strains isolated from adult patients at different seasons of the year].

Biological properties of Salmonella strains, isolated in different seasons from patients with the corresponding disease of moderate severity, were compared. Their morphological, biochemical, serologic properties, sensitivity to antibiotics, capacity for synthesizing O-antigen, as well as their virulence for experimental animals, have been studied. Seasonal changes in the virulence of Salmonella strains have been established: the strains isolated in autumn have proved to be more virulent than those isolated in winter. In winter the isolation rate of Salmonella strains resistant to the therapeutic doses of antibiotics is significantly higher than in other seasons. In spring and summer Salmonella O-antigen is synthesized more intensively.