Rapid determination of the activity of bacteriolytic factors of milk against bacteria of three different families

This study proposes a method for determining the total content of bacteriolytic factors using cow’s milk samples. Bacteriolytic factors (lysozymes, lactoferrins, cationic antimicrobial peptides) play a crucial role in the mammalian immune system. Measuring bacteriolytic activity by turbidimetry, based on the rate of bacterial suspension clarification, is simple and rapid. Three bacteria types from different families were used in the study: gram-positive Micrococcus luteus (a representative of human symbiotic flora), gram-negative Escherichia coli (a representative of human symbiotic flora and an analogue of dangerous pathogens from the same family), and spore-forming gram-negative bacilli, Priestia megaterium (a nonpathogenic analogue of the anthrax pathogen). Activity values for 50 cow’s milk samples against each of the bacteria were obtained. The ratios of the obtained values characterize the parameters of milk varieties obtained from 50 animals of the same species and breed. Some types of milk have been identified that exhibit antimicrobial activity against different groups of bacteria. The rapid nature of the method allows formation of a large database and, with its help, the development of a rapid and accessible diagnostic system for pathologies in dairy cattle. The same groups of antimicrobial factors are present in human milk, so further application of the proposed method holds great promise in veterinary and medical diagnostics.