Enzymatic characterization of Staphylococcus aureus strains: a possible role of habitat and methicillin-resistance in the determination of the differences observed.

Twenty five strains of Staphylococcus aureus of human and environmental origin were tested for their enzymatic patterns. All human strains possessed acid phosphatase, while only 25% of the environmental staphylococci demonstrated acid phosphatase activity. In addition, the enzyme alpha-glucosidase was present only in the methicillin resistant-multiresistant strains, in spite of their origin. This work suggests a possible role of the enzyme on penicillin-binding protein mediated methicillin-resistance and stresses the importance of external habitat in the expression of enzymatic activity of bacteria. The enzymatic pattern may confirm or exclude cross-infection, when a single species, with uniformly antibiotic responses, is involved.