Adherence of alpha-hemolytic streptococci to human endocardial, endothelial and buccal cells

Human buccal, endothelial and endocardial cells were prepared and the adherence of different bacteria to these cells was tested in vitro. Buccal cells were scraped off immediately before use in the adherence tests. Endothelial and endocardial cells were prepared from human umbilical vein and human heart valves by using collagenase, and cultured in cell culture medium. Seventeen different bacteria were used in the adherence tests; ten strains of alpha-hemolytic streptococci, five from children with infective endocarditis (IE) and five from healthy carriers, two S. aureus, two N. meningitidis, two N. gonorrhoeae and one E. coli. The five alpha-hemolytic streptococcal strains from patients with IE showed significantly higher adherence values than those from healthy carries as well as in comparison with the remaining seven bacteria. The difference in adherence might be an expression for different bacteria surface properties. These differences might be important in explaining the infective mechanism in infective endocarditis.