Mechanisms of Staphylococcus aureus invasion of cultured osteoblasts

Staphylococcus aureus is a bacterial pathogen causing approximately 80% of all cases of human osteomyelitis. This bacterium can adhere to and become i nternalized by osteoblasts and previous studies indicate that osteoblasts a re active in the internalization process. In the current study, we examined the roles of microfilaments, microtubules and clathrin-dependent receptor- mediated endocytosis in the internalization of S. aureus by MC3T3-E1 mouse osteoblast cells. Microfilament and microtubule polymerization was inhibite d with cytochalasin D and colchicine. Clathrin-coated pit formation was exa mined by using the transaminase inhibitor, monodanslycadaverine. The result s of this study indicate that mouse osteoblasts utilize actin microfilament s, microtubules and clathrin-coated pits in the internalization of S. aureu s; however, microfilaments seem to play the most significant role in the in vasion process. (C) 1999 Academic Press.