The Significance of Sodium Chloride in Studies of Staphylococci

Abstract

75 grams NaCl added to 1 liter of Bacto phenol red mannitol agar provided an excellent medium for the isolation of staphylococci. Pathogenic types produced large colonies in 36 hrs. surrounded by yellow zones; nonpathogenic types produced small colonies without yellow zones. Other bacteria rarely grew on the medium. Proteose lactose agar containing 75 grams NaCl per 1. was excellent for stock cultures. It enhanced chromogenesis and coagulase production and reduced the proportion of "degenerate" dissociants. The recovery of plasma coagulating staphylococci was far better than by any previous method.