In vitro adhesion of Staphylococcus strains to rabbit tissues

Differences in the in vitro adhesion of Staphylococcus strains on rabbit tissues were evaluated by viable unit counts and radio-labeling. Among coagulase-positive strains, two freshly isolated strains and the Cowan I strain adhered much more than the Wood 46 strain especially to peritoneum. In addition, the Smith strain, which is coagulase-positive and encapsulated, showed on rabbit peritoneum a degree of adhesion smaller than that of the Cowan I strain and similar to that of the Wood 46 strain. These quantitative results were corroborated by examination of the bacteria on thin sections of peritoneum or on whole mesentery samples with fluorescence microscopy. With fluorochroming either with acridine orange or fluorescent homologous antibodies, we could detect a preferential localization of the bacteria on the epithelium and also on fibers of the mesentery. Even if the Cowan I strain produces Protein A, this substance does not seem to have been involved in the adhesion of this strain to rabbit tissues, since IgG did not affect the degree of its adhesion. Treatment by Na metaperiodate of the peritoneum had an inhibitory effect of about 50% on the degree of adhesion; several other known inhibitors had no effect. The higher affinity of the Cowan I strain for the peritoneum or the mesentery, when compared with the Wood 46 strain, is an observation which could contribute to the study and understanding of adhesion, presumably an element of the experimental pathogenicity of Staphylococcus.