The initiation of many infectious diseases involves specific adhesion of ba
cteria to host tissue proteins and carbohydrates. Staphylococcus aureus is
known to bind specifically to several proteins in the extracellular matrix
(ECM). We report the quantification of the collagen and fibronectin adhesin
densities on the staphylococcal surface using flow cytometry. Our results
are in agreement with previous reports on the transcription of the respecti
ve genes and demonstrate different patterns of temporal expression for the
two adhesins in the strains studied. We demonstrate a convenient technique
for quantification of bacterial adhesins that can be used in studies aimed
at characterization of bacterial adhesion to ECM components and understandi
ng expression of adhesins during the course of an infection. (C) 2000 Acade
mic Press.