Effect of Sodium Chloride on Growth, Glucose Utilization, and Acid Production in Proteus Vulgaris.

During an evaluation of selective plating media for identification of coagulase-positive staphylococci in foods, two strains of Proteus vulgaris produced wider zones of acidity on plates containing NaCl than on those without the salt. Subsequent experiments showed that NaCl was responsible and that it also increased acid production in broth. Because P. vulgaris frequently interferes with the isolation from foods of organisms of public health significance, the effect of NaCl on the growth of the organism was thought worthy of further study. The response of P. vulgaris ATCC 4669 to 0.5% NaCl, a commonly employed concentration, was studied in a 1.8% solution of N-Z Amine YT (Sheffield Chemical Co., Norwich, N.Y.) in "Nephalo-flasks" (Bellco Glass Co.,