OCCURRENCE AND ENUMERATION OF BDELLOVIBRIO BACTERIOVORUS IN SOIL CAPABLE OF PARASITIZING ESCHERICHIA COLI AND INDIGENOUS SOIL BACTERIA

Abstract

A plating technique was developed for the enumeration of soil Bdellovibrio bacteriovorus parasitic on Escherichia coli. With this technique, the parasite was detected in all of 23 soils examined, and counted in 21 of them. Soil-derived Bd. bacteriovorus parasitic on E. coli serogroup OX9 and strain 167 were found to parasitize all of 25 other E. coli serogroups tested, as well as the smooth and rough forms of E. coli strain MGH6. Examination of the sensitivity to Bd. bacteriovorus of stock cultures of various soil-derived bacteria, and of the sensitivity of bacteria randomly isolated from soil by the Lochhead and Chase "non-biased" isolation procedure, revealed that indigenous hosts for this organism occur in the soil.