EFFECT OF ALPHA-TOXIN AND CAPSULAR EXOPOLYSACCHARIDE ON THE ADHERENCEOF STAPHYLOCOCCUS-AUREUS TO CULTURED TEAT, DUCTAL AND SECRETORY MAMMARY EPITHELIAL-CELLS

Cultures of teat, ductal and secretory epithelial cells were used to s tudy the role of alpha-toxin and the capsular exopolysaccharide on the adherence of Staphylococcus aureus to mammary epithelium. The adheren ce of S aureus to the cells and their susceptibility to damage by alph a-toxin increased from teat to ductal to secretory cells. Alpha-toxin increased the susceptibility of epithelial cell monolayers to adherenc e by S aureus, and the extent of the adherence increased with the time of exposure to alpha-toxin. The exopolysaccharide capsule deterred th e adherence of S aureus to mammary epithelial cells and to collagen. O rganisms with a rigid capsule adhered to a smaller extent than those w ith a flaccid capsule. Both encapsulated and unencapsulated S aureus a dhered more readily to collagen than to either healthy monolayers of e pithelial cells or monolayers of cells damaged by alpha-toxin.