Microorganisms can colonize and proliferate on and in medical instruments under appropriate environmental conditions. They excrete slimy exopolysaccharides (EPS) and thus form a biofilm.

Microorganisms are much more resistant to antimicrobial agents in the biofilm than they are in suspension. Although physical processes (such as ultrasound and mechanical cleaning) are effective for the removal of biofilms, they are difficult to put into practice, which is why chemical processes are predominantly used.

To test chemical methods, SMP reproducibly grows artificial biofilms with Pseudomonas aeruginosa in Teflon tubing. Detergents and disinfectants can be tested for their microbiological effectiveness on the tube models. The microbiological, quantitative evaluation of the chemistry to be investigated is carried out by determining the reduction of the number of vital bacterial cells by means of plating..

In addition, the removal of the biofilm is examined by staining. The dye bound to the biofilm is subsequently eluted. The evaluation of the remaining biomass is done in the photometer by quantifying the amount of dye in the eluate.

The selection of Pseudomonas aeruginosa as a test organism according to DIN ISO/TS 15883-5.