COMPARISON OF SELECTIVE AGARS FOR THE ISOLATION AND IDENTIFICATION OFKLEBSIELLA-OXYTOCA AND ESCHERICHIA-COLI FROM ENVIRONMENTAL DRINKING-WATER SAMPLES

Various selective media were assessed for their ability to detect and differentiate Klebsiella oxytoca and Escherichia coli in environmental water samples. Only two, Membrane Lauryl Sulphate agar and Deoxychola te Agar, could differentiate the two coliforms from each other and fro m the 'background' heterotrophs in water and this was a consequence of E. coli's ability to grow at 44 degrees C and 37 degrees C whereas Kl . oxytoca could only grow at 37 degrees C. Modified M-FC medium effect ively differentiated KI. oxytoca but not E. coli in environmental samp les. Other media characterized the different coliforms in pure culture but failed to do likewise in environmental samples. For example, pure cultures of E. coli fluoresced when MUG was added to the medium but s ingle colonies on a mixed species plate failed to do so. MT7 agar dist inguished the two coliforms from water heterotrophs but not from each other.