Selective Enumeration of Bifidobacterium bifidum, Enterococcus faecium, and Streptomycin-Resistant Lactobacillus acidophilus from a Mixed Probiotic Product

Abstract

Modified VF-Bouillon agar with 0.5 mg/ml lithium chloride, 20 μg/ml sodium lauryl sulfate, 5 mg/ml sodium propionate, and 10 μg/ml neomycin sulfate was used with a triple-layer diffusion technique to selectively enumerate Bifidobacterium bifidum. Modified Brigg's agar was used to enumerate Enterococcus faecium. Modified Brigg's agar with 1,200 μg/ml streptomycin sulfate was used in a double-layer diffusion technique to selectively enumerate a streptomycin-resistant strain of Lactobacillus acidophilus. Selective enumeration of the individual bacterial components was compared to the mixture with an average 99% recovery of each component.