Routine disinfection of patients' environmental surfaces. Myth or reality?

We have evaluated the need for daily disinfection of environmental surfaces not contaminated by biological fluids, in patient areas of a medical unit with two wings [North (N) and South (S)] at the University Hospitals of Gen eva, Switzerland. Weekly bacteriological monitoring of surfaces was carried out at random (N = 1356 samples). In the S wing (control), we used deterge nt/disinfectant for daily cleaning of the floors and furniture. In the N wi ng we began by using a detergent for floors and furniture; after four weeks the results suggested changing to a rotation of detergent, dust attracting disposable dry mops and disinfectant. During this period the furniture was cleaned with an active oxygen-based compound. The average differences in c ontamination before and after cleaning floors were (mean reduction in bacte rial counts and 95% confidence intervals; CI95): disposable mops: 92.7 cfu/ 24 cm(2) (CI95; 74-112), active oxygen based compound 111.1 (90-133), and q uaternary ammonium compound -0.6 (-27-26). Use of detergent alone was assoc iated with a significant increase in bacterial colony counts: on average by 103.6 cfu (CI95 73-134). The quaternary ammonium compound was inadequate f or disinfecting bathrooms and toilets but the active oxygen based compound was satisfactory. For furniture, there was a significant reduction in bacte rial counts with both the methods using disinfectants. As the detergent was contaminated, by using it alone for cleaning, we were actually seeding sur faces with bacteria. A total of 1117 patients was studied and we observed no change in the incid ence of nosocomial infections during the four months of the trial. In concl usion, uncontrolled routine disinfection of environmental surfaces does not necessarily make it safe for the patient and could seed the environment wi th potential pathogens.