Differentiation of strains of Staphylococcus epidermidis biotypes 1 and 4 by aminopeptidase profiles

Seven different strains of Staphylococcus epidermidis and one strain of S. aureus were catagorized by their aminopeptidase activity. Eight different profiles were obtained: five profiles for S. epidermidis biotype 4 (each representing a different known serotype), two profiles for S. epidermidis biotype 1 (one for each strain used) and one for the strain of S. aureus used. Despite some similarities, distinct patterns of the hydrolysis of 22 different amino acid-beta-naphthylamides were evident for each individual strain. The evaluation of aminopeptidase profiles provides another means for distinguishing between strains of the same species and can, therefore, be used advantageously and in combination with serotyping as an epidemiological tool.