Association between a probiotic-based cleaning strategy and healthcare-associated infection incidence: a hospital-based quasi-experimental study.

BACKGROUND

The hospital environment contributes to the transmission of healthcare-associated infections (HAIs). Probiotic-based cleaning represents an ecological approach aimed at modulating the surface microbiota through bacterial competition rather than eliminate it.

OBJECTIVE

The aim of this study was to assess whether probiotic cleaning was associated with a change in the incidence density of microbiologically documented HAI episodes compared with conventional biocide cleaning.

METHODS

A single-centre, quasi-experimental before-and-after study compared two consecutive 12-month cleaning periods. Potential HAI episodes were identified through monthly retrospective extraction of routine laboratory data and adjudicated from medical records using European Centre for Disease Prevention and Control (ECDC) definitions. Incidence densities were expressed per 1000 patient-days and compared using an exact Poisson rate test.

RESULTS

The study included 5753 hospitalizations, representing 37,511 patient-days during the biocide period and 32,453 during the probiotic period. Among the 475 laboratory-identified potential HAI episodes, 188 episodes during the conventional biocide control period and 117 episodes during the probiotic intervention period met the relevant ECDC criteria for an HAI. Incidence density was lower during the probiotic period (3.61 vs 5.01 episodes per 1000 patient-days; crude incidence rate ratio, 0.72; 95% confidence interval, 0.57-0.91; P = 0.005), corresponding to an approximately 28% lower crude rate.

CONCLUSION

Probiotic cleaning was associated with a lower crude incidence rate of microbiologically documented HAI episodes. Given the non-randomized design, potential residual confounding, and absence of environmental sampling, causal and mechanistic conclusions cannot be drawn. Controlled multi-centre studies are needed to confirm these findings.