Identification and pathogenic (toxicogenic) potential of Staphylococcus haemolyticus and Bacillus paranthracis consortia isolated from bovine mastitis in Russia

Bovine mastitis is one of the most economically important diseases in cattle. Infectious mastitis has a viral or bacterial origin. The most common bacterial agents are Staphylococcus , Streptococcus , coliforms, and Bacillus species. These are opportunistic microorganisms that can switch to a pathogenic form, using various virulence factors with follow various pathologies, both animal and human. Three stable microbial consortia, each composed of Bacillus paranthracis and Staphylococcus haemolyticus strains, were isolated from milk of cows diagnosed with mastitis in three geographically remote regions of Russia. The composition of these consortia remained stable following multiple passages on culture media. Apparently, this stability is due to the structure of the microbial biofilms formed by the communities. The virulence of the consortia depended on the B. paranthracis strains. It seems plausible that the ability of the consortia to cause mastitis in cattle was affected by mutations of the cytK gene of B. paranthracis .