Environmental cleaning to prevent hospital-acquired infections on non-intensive care units: a pragmatic, single-centre, cluster randomized controlled, crossover trial comparing soap-based, disinfection and probiotic cleaning.

Background: The impact of environmental hygiene on the occurrence of hospital-acquired infections (HAIs) remains a subject of debate. We determined the effect of three different surface-cleaning strategies on the incidence of HAIs. Methods: Between June 2017 and August 2018 we conducted a pragmatic, cluster-randomized controlled crossover trial at 18 non-ICU wards in the university hospital of Berlin, Germany. Surfaces in patient rooms on the study wards were routinely cleaned using one of three agents: Soap-based (reference), disinfectant and probiotic. Each strategy was used on each ward for four consecutive months (4m-4m-4m). There was a one-month wash-in period at the beginning of the study and after each change in strategy. The order of strategies used was randomized for each ward. Primary outcome was the incidence of HAIs. The trial was registered with the German Clinical Trials Register, DRKS00012675. Findings: 13,896 admitted patients met the inclusion criteria, including 4708 in the soap-based (reference) arm, 4535 in the disinfectant arm and 4653 in the probiotic arm. In the reference group, the incidence density of HAIs was 2.31 per 1000 exposure days. The incidence density was similar in the disinfectant arm 2.21 cases per 1000 exposure days (IRR 0.95; 95% CI 0.69-1.31; p = 0.953) and the probiotic arm 2.21 cases per 1000 exposure days (IRR 0.96; 95% CI 0.69-1.32; p = 0.955). Interpretation: In non-ICU wards, routine surface disinfection proved not superior to soap-based or probiotic cleaning in terms of HAI prevention. Thus, probiotic cleaning could be an interesting alternative, especially in terms of environmental protection. Funding: Federal Ministry of Education and Research of Germany (03Z0818C). Bill and Melinda Gates Foundation (INV-004308).