Environmental services redesign and hospital-acquired CPE acquisition in a tertiary-care hospital: an interrupted time-series study

Objective To evaluate whether a staffing-neutral redesign of hospital environmental services, involving functional separation of routine cleaning and infection control–focused disinfection, was associated with improved environmental hygiene reliability and lower hospital-acquired carbapenemase-producing Enterobacterales (CPE) acquisition. Design Retrospective quasi-experimental interrupted time-series evaluation. Setting A 2,000-bed tertiary-care hospital in Seoul, South Korea. Intervention Beginning in January 2025, environmental services were reorganized without increasing total staffing by functionally separating routine cleaning and infection control–focused disinfection into dedicated workstreams. Personnel were reallocated from routine cleaning to dedicated disinfection, ward-level disinfection frequency increased, and replacement coverage was expanded hospital-wide. Methods Monthly hospital-acquired CPE acquisition counts from January 2023 through December 2025 were analyzed using segmented Poisson regression with patient-days as an offset and calendar month indicators for seasonality. Environmental hygiene audit performance and hand hygiene compliance among environmental services workers were assessed descriptively as supportive implementation indicators. Results The pre-intervention hospital-acquired CPE acquisition rate was 1.00 per 1,000 patient-days, compared with 0.70 per 1,000 patient-days in the post-intervention period, representing a 30.3% relative reduction. In segmented Poisson interrupted time-series analysis, the redesign was associated with a significant immediate level reduction in hospital-acquired CPE acquisition (incidence rate ratio [IRR], 0.52; 95% confidence interval [CI], 0.37–0.74; P < .001). The post-intervention slope increased relative to the pre-intervention trend (IRR, 1.12; 95% CI, 1.08–1.16; P < .001), suggesting partial attenuation over time. Conclusions In this large tertiary-care hospital, a staffing-neutral redesign of environmental services was associated with lower hospital-acquired CPE acquisition without additional workforce expansion. Organizational redesign of environmental hygiene programs may represent a feasible and scalable quality improvement strategy in resource-constrained hospital settings.