ABSTRACT
Central dosing units for surface disinfectants can constitute a particular hygiene problem in hospitals if a biofilm can develop in the piping system despite the disinfectant solution that is present. In earlier studies it was able to be shown that oxygen-releasing compounds in particular were highly effective against microorganisms in generated biofilms. The purpose of the study presented was to investigate in a test simulating practical conditions whether, in addition to the described good effect, peroxide-containing solutions also have a uniform effect against all isolates from disinfectant use-solutions, or whether there are differences. The results show that a 1% H2O2 solution (C) was not sufficiently effective against all test organisms after a contact time of one hour. In contrast, the 1% test solution of A (10% perglutaric acid, 28% H2O2, < 0.5% perbenzoic acid) was highly and uniformly effective. The 3% test solution of B (10% tertiary butylhydroperoxide, 20% phenoxypropanols, 48% dipropylene glycol) exhibited weaknesses against some test organisms after the one-hour contact time. After a contact time of three hours, this solution, unlike the 1% H2O2 solution achieved a reduction in bacterial count of more than 5 log steps against all species. On the basis of these results, before cleaning piping systems it appears advisable to test the effectiveness of the solution to be used in a suitable test with the isolates.
