Sustained decline in healthcare-associated infections despite stabilized antimicrobial use: a 10-year study in Southwestern China.

Healthcare-associated infections (HAIs) and antimicrobial use (AMU) remain major patient safety challenges worldwide, particularly in low- and middle-income settings. However, long-term population-based evidence describing their joint temporal evolution in relation to diagnostic stewardship remains limited. We conducted a 10-year repeated cross-sectional study using annual point-prevalence survey (PPS) data from secondary and tertiary hospitals and other voluntarily participating institutions in Yunnan Province, China, between 2015 and 2024. Temporal trends in HAI prevalence, AMU prevalence, overall culture rate, and pre-prescription culture rate were evaluated using interrupted time series (ITS) analysis as the primary method, supplemented by exploratory segmented regression. Hospital size–stratified analyses were performed to assess differential improvement trajectories across facilities. A total of 1,135,037 inpatients from up to 381 hospitals were included. Overall HAI prevalence declined from 2.11% to 0.92%, representing a 56.4% relative reduction (p for trend < 0.001), with an accelerated decrease observed after 2020. In contrast, AMU prevalence stabilized around 33% after 2020, showing a biphasic pattern with pre-pandemic decline followed by post-pandemic stabilization. The overall culture rate increased from 59.6% in 2015 to 74.5% in 2024. Meanwhile, the pre-prescription culture rate increased substantially, from 49.1% in 2017 to 68.4% in 2024. This divergence between HAI and AMU trends was accompanied by a shift toward more rational prescribing patterns, characterized by higher proportions of therapeutic use and single-agent regimens. Improvements were more pronounced among smaller hospitals, resulting in a narrowing of inter-hospital disparities. Sustained reductions in HAI prevalence were achieved despite stabilization of overall antimicrobial consumption. These findings suggest that pre-prescription culture testing was associated with improved AMU quality and reduced HAI prevalence and strengthened infection prevention efforts. This 10-year real-world evidence supports prioritizing diagnostic stewardship as a core component of long-term infection control strategies, especially in resource-constrained settings.