Determination of Antibiotic Resistance in Bacillus Isolated from Soil

Abstract

In order to determine antibiotic resistance in Bacillus, Gram positive bacilli were isolated from soil collected from a number of different sites in Frederick County, Md. The Bacillus strains were then tested by the standard agar dilution method for determining antibiotic resistance. Several strains which showed apparently high levels of resistance by this method were subsequently tested quantitatively. The titration of the number of surviving cells against increasing concentrations of antibiotic did not correlate with the Minimal Inhibitory Concentration (NI) determined by the agar dilution method. There was in fact no significant degree of drug resistance demonstrated in any strain of Bacillus isolated.