Surface properties of cells of some methicillin-resistant strains of Staphylococcus aureus.

Methicillin-sensitive (MS) cells of Staphylococcus aureus had a minimum electrophoretic mobility at pH 4.5, whereas methicillin-resistant (MR) strains showed only a slight plateau effect. Trypsin removed the trough effect of the MS Oxford strain. There was no correlation between surface lipid and resistance in MR strains. Cell walls of MS strains contained much more teichoic acid than walls of MR strains. Lysostaphin lysed all MR and MS strains, and mucopeptide does not appear to be involved in resistance to methicillin.