MICROTITRATION PLATE MOST-PROBABLE-NUMBER TESTS FOR THE ENUMERATION OF ESCHERICHIA-COLI IN ESTUARINE AND MARINE WATERS

Microtitration plate most-probable-number tests were developed for the estimation of Escherichia coli numbers in estuarine and marine waters . A 32-well test was adequate for testing most waters, although the en tire plate could be used for each dilution in waters containing low nu mbers of E. coli. The incorporation of 4-methylumbelliferyl-beta-D-glu curonide into modified A-1 broth facilitated the identification of E. coli. Values obtained by using microtitration plate most-probable-numb er tests correlated with those obtained by using standard 3- and 5-tub e most-probable-number tests, but were more precise and reproducible.