CLOSTRIDIUM PERFRINGENS ШТАММДАРЫНЫҢ ВИРУЛЕНТТІЛІГІНЕ ӨСІРУ УАҚЫТЫНЫҢ ӘСЕРІ

This study investigated the biological properties of Clostridium perfringens strains of types B, C, and D, as well as type C isolates obtained from KazNIVI. The aim of the study was to assess the virulence of these strains using the lethal dose (LD₅₀) and to evaluate the effect of cultivation time on their biological activity in order to substantiate the critical importance of the time factor in the development of immunobiological preparations against infectious diseases. The cultures were grown in Kitt–Tarozzi medium under anaerobic conditions for 8, 16, 24, and 48 hours. The resulting suspensions were administered to white mice, and mortality was recorded. LD₅₀ values were calculated using the Kerber–Ashmarin method. The results demonstrated that the virulence of Clostridium perfringens strains is directly dependent on cultivation time. The highest virulence was observed at 8–16 hours of growth, whereas a decrease was noted at 24–48 hours, which is associated with changes in bacterial growth phases and toxin production. These findings highlight the critical importance of cultivation time when developing immunobiological preparations against infectious diseases.