Classification of Staphylococcus Epidermis Albus From Human Skin

Abstract

Staphylococci were obtained from the skin (palmer and dorsal surfaces of hand, over chest and back), under the nails at the tips of fingers and from the margins of the nail on their dorsal surface. Sterile swabs moistened with saline were used to obtain specimen. Standard technical procedures and media were used. Seventy-five strains from the skin, under the nail and the dorsal margin of the nails were classified. The production of acid upon lactose, maltose, dextrose, mannite and litmus milk and the reduction of nitrates and the liquefaction of gelatin were determined. Acid production upon lactose media proved to be the differentiating reaction. Eighty-four per cent of the skin strains of Staphylococcus epidermis albus fermented lactose, half of the same strains of staphylococci from the dorsal margin of the finger-nail fermented lactose and half did not produce acid from this sugar. Only 15% of the Staphylococcus epidermis albus isolated from under the nail at the tips of the fingers fermented lactose, 85% did not produce acid when grown in contact with this sugar.

All of the strains are practically non-pathogenic for mice, conforming to the usual findings in this respect. The work is being continued to ascertain if post-operative and other pyogenic infections contain the skin or under the nail strains of Staphylococcus epidermis albus.