Attempt in classification of catalase-positive staphylococci and micrococci.

Mossel, D. A. A. (Central Institute for Nutrition and Food Research T.N.O., Utrecht, The Nethrlands). Attempt in classification of catalase-positive staphylococci and micrococci. J. Bacteriol. 84:1140-1147. 1962.-About 390 strains of Staphylococcus aureus, isolated from clinical material, and about 190 strains of coagulase-negative staphylococci and micrococci from strictly nonclinical habitats were studied by the following recently recommended biochemical tests: anaerobic dissimilation ("fermentation") of mannitol, gelatin liquefaction, type of growth on tellurite-glycine agar, hydrolysis of urea, and KCN tolerance. The latter three tests appeared either not specific for, or not positive for, most S. aureus strains. Virtually all strains of S. aureus were gelatin-positive, but 71% of the other types of cocci also liquefied gelatin. Rapid anaerobic breakdown of mannitol, however, was shown by ca. 95% of the strains of S. aureus, and late fermentation by an additional 3%. Of 105 obligately aerobic coagulase tive cocci (micrococci), none fermented mannitol; of 40 facultatively anaerobic, coagulase-negative cocci (staphylococci), only 7 (18%) fermented mannitol. Oxidative metabolism of mannitol occurred in only three (<1%) strains of S. aureus but was detected in roughly half of the isolates of both groups of coagulase-negative cocci. Pigmentation was confirmed to be of little value, because roughly 50% of both coagulase-positive and -negative strains showed a pale-yellow color on Chapman's mannitol salt agar while 13% of the S. aureus strains tested were white. A key to the classification of catalase-positive cocci consistent with that currently used for Enterobacteriaceae has been based on these figures.