Differentiation by electrophoresis and enzymoserology of proteinases, produced by strains of Staphylococcus epidermidis biotypes 1 and 4

Electrophoretic and serologic characterization of extracellular proteinases from 111 isolates (80 biotype 1 and 31 biotype 4) of Staphylococcus epidermidis (coagulase negative) of human origin were conducted. Seventy-seven (60 of biotype 1, 17 of biotype 4) of the 111 proteinase-positive isolated of S. epidermidis were classified by serological differentiation of their proteolytic enzymes with known specific antisera. Thirty-two (18 of biotype 1, 14 of biotype 4 (isolates of S. epidermidis produced proteolytic enzymes that did not react with any of the known group antisera and were classified as NR (non-reacting). No classification of the enzymes of two other isolates was possible. The NR proteinase enzymes from the 32 cultures that could not be classified by serological differentiation with the known specific antisera fitted into one of three electrophoretic mobility patterns: NR1, NR2 or NR3. Seventy-eight isolates of S. epidermidis biotype 1 were placed into four proteinase sero-groups; 49 in F, 11 in B, 11 in NR2, and 7 in NR3. Thirty-one isolates of S. epidermidis biotype 4 were placed into one of two groups: 17 in C and 14 in NR. All enzymes tested migrated towards the anode at pH 8.6, and the order of electrophoretic mobility was NR3 greater than F greater than NR2 greater than NR1 greater than B greater than C.