[Effect of heavy metals and pesticides on the antigenic behavior of mastitis staphylococci isolated from cows and sheep].

Evaluated was the effect produced by some heavy metals and pesticides on the antigenic behaviour of Staphylococcus aureus strains isolated from cows and sheep with mastitis. The experiments were carried out with 9 strains, their antigenic structure being determined with the use of 16 factor sera prior to and after being gradually acted upon with lead acetate, copper sulfate, zinc sulfate, cadmium, and herbazin-50. It was found that under the effect of these chemical factors the capsule-resembling layer grew. In connection with this the staphylococci grew within the nutrient media, forming mucoid colonies. The serologic analysis revealed lower agglutinin ability due to the release of deeply set antigens. The growth of the capsular layer was associated with the increase in the virulence of staphylococci, which was established in the conditions of the practice on a dairy farm adjacent to a Copper producing Works.