A Modified Eijkman Medium

Abstract

On a medium, consisting of Difco peptone 15 gm., glucose 3 gm., K2BPO4 4 gm., NaCl 5 gm., and water 1000 cc, the average number of Bacillus coli (so-called fecal type) isolated from 24 specimens of fresh human feces was 199.2 millions, as compared to 141.1 millions per gm., using standard lactose broth. This modification results in a final pH of approximately 5.6 after fermentation with B. coli, as compared to pH 45 with the original Eijkman medium, thus preventing death of cultures after 24 and 48 hrs. of incubation at 46[degree] C. This work confirms the fundamental value of the Eijkman test as an initial step in isolating B. coli from water, etc.