Hemagglutination by Staphylococcus saprophyticus and other coagulase-negative staphylococci

Hemagglutination tests were performed to specify surface lectins (hemagglutinins) of four coagulase-negative staphylococcal species: S. saprophyticus (31 strains), S. epidermidis (5 strains), S. haemolyticus (3 strains), and S. warneri (3 strains). All strains of S. saprophyticus agglutinated sheep red blood cells (RBC) and the hemagglutination was inhibited by N-acetylglucosamine (GlcNAc) plus either N-acetylgalactosamine (GalNAc, 15 strains) or N-acetylneuraminic acid (NANA, 16 strains). Those strains showing inhibition by GalNAc also agglutinated horse RBC while those inhibited by NANA agglutinated rabbit RBC. The former type was more common among urinary tract isolates (10/15) and the second one among respiratory isolates (9/14). The eleven strains of other staphylococci agglutinated rabbit (and not sheep or horse) RBC; this hemagglutination was never inhibited by GlcNAc but instead by NANA alone or together with another sugar (7 strains) or by other sugars (4 strains, 3 different patterns of inhibition).