Sub-lethal concentrations of aminoglycosides enhanced the adherence of Staphylococcus aureus FDA 209P to HeLa cells, whereas beta-lactams, pyridone carboxylic acid derivatives and chloramphenicol did not. Treatment with aminoglycosides also enhanced the bacterial adherence of these cells to immobilized fibronectin and laminin, and changed the bacterial cell surface to a more hydrophilic state than exists in non-treated cells. The adherence of S. aureus was not inhibited by lipoteichoic acid, extracted from the same strain, regardless of whether the bacterial cells were treated with an aminoglycoside or not. No correlation was observed between the adherence and zeta-potential of S. aureus.