Comparison of agar-based methods for the isolation and enumeration of heterotrophic bacteria with the new Multidose IDEXX (TM) SimPlate method

摘要

Pour and spread plates are the conventional methods of choice for the isolation and enumeration of heterotrophic microorganisms in treated water supplies. The tests are performed at 22degreesC and 37degreesC for 72 h and 48 h respectively. Counts at 22degreesC are associated with pollution of water systems from external sources, while counts at 37degreesC are used as an indication of treatment plant performance and the deterioration of the general quality of water. Conventional methods using Yeast Extract Agar for a pour plate and R(2)A agar for a spread plate were compared with the multiclose IDEXX(TM) SimPlate method for the isolation and enumeration of heterotrophic bacteria in water. SimPlate gave a significantly higher count on average than the conventional methods. The R2A method showed the next highest count, being significantly higher than Yeast Extract Agar. In addition, unlike the pour and spread plate methods, SimPlate was easier to use, reduced labour, and the test results were far easier to read.