Hemagglutination by Staphylococcus aureus. Studies on strains isolated from bovine mastitis

Staphylococcus aureus strains isolated from bovine mastitis exhibited hemagglutinating activity when cultivated on nutrient-poor, solid medium. Out of 56 strains, 41 (73%) hemagglutinated. S. aureus agglutinated sheep erythrocytes to a greater extent than it agglutinated either human, bovine or equine erythrocytes. Hemagglutination was more conspicuous with erythrocytes from certain sheep individuals, indicating blood-group specificity. Receptors on sheep erythrocytes were apparently of carbohydrate nature since periodate-treated erythrocytes were not agglutinated. Hemagglutinating properties were associated with the ability to adhere to human buccal cells. Crude staphylococcal extracts were able to partially inhibit bacterial adherence to epithelial cells.