Selective Media for the Isolation of Gram-Negative Anerobic Rods

Part II. Distribution of Gram-Negative Anaerobic Rods in Feces of Normal Human Beings

Abstract

By means of CNBGT medium for Bacteroides and a modified FM medium for Sphaerophorus, many strains were isolated from the feces of ten normal human beings. They were identified with the following results.
1) In human feces, 10^8-11 cells of Bacteroides and 10^8-10 cells of Sphaerophorus were found per gram. The former were always predominant over the later.
2) Of the species of Bacteroides, B. convexus was the most predominant and followed by B. thetaiotaomicron, B. terebrans, B. putidus, B. melaninogenicus, and B. fragilis in this order of frequency.
3) Of the species of Sphaerophorus, Sph. necrophorus was the most predominant. Some unidentified strains, Sph. freundii, Sph. siccus, Sph. varius, and Sph. pyogenes followed it in this order of frequency.