Biofilms disinfectant tests

Compared with suspended (planktonic) cells, bacteria on surfaces as biofilms are invariably phe-notypically more resistant to antimicrobial agents. With biofilms, suspension tests can be modified to involve biofilms produced on small pieces of an appropriate glass or metal substrate, or on the bottom of microtitre tray wells. After being immersed in, or exposed to the disinfectant solution for the appropriate time interval, the cells from the biofilm are removed, e.g. by sonication, and resuspended in a suitable neutralizing medium. Viable counts are then performed on the resulting planktonic cells. 

Johnston, M. D. and Jones, M. V., 1995. Disinfection tests with intact biofilms combined use of the Modified Robbins Device with impedance detection. Journal of Microbiological Methods 21, 15-26. 

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