[Model tests for effectiveness assay of disinfectants on surfaces. III. Dependence of test results on the type of substances and the test microbes (Staphylococcus aureus, Mycobacterium terrae)].

A new test method for surface disinfectants was applied to investigate the efficacy of the most important active components of disinfectants to Staphylococcus aureus and Mycobacterium terrae. The test germs were embedded in coagulated blood. Frosted glass served as test surface. The disinfection was performed by applying a fixed amount of the disinfectant and mixing it with the contamination by rubbing. The number of surviving germs was determined quantitatively. Generally, the two test germs showed a distinctly different behaviour towards the active substances applied. Mycobacteria proved to be clearly more resistant than staphylococci, except with formaldehyde and the cresol-soap solution. The formaldehyde, the mycobacteria were only a little more resistant, while to cresol-soap solution they were even a little more sensitive than were staphylococci. Compounds containing active chloride showed a sufficient effect on mycobacteria only if the consumption of the active component by blood was nearly excluded. The quaternary ammonium compound and glyoxal, even the high concentrations, showed a totally insufficient efficacy to mycobacteria. The results shall provide the basis for a new guideline to be established by the Federal Health Office concerning the efficacy testing of surface disinfectants effective against mycobacteria, especially tuberculosis bacteria.