From Screening to Outcomes: Fourteen-Year Hospital-Wide Surveillance of Alert Pathogens and Antimicrobial Use in a Paediatric Tertiary Hospital

<b>Background/Objectives</b>: Infection prevention and control (IPC) programs combine pathogen-targeted measures (e.g., admission screening) with hospital-wide standard precautions (e.g., hand hygiene, HH). We assessed temporal associations between screening, HH, antimicrobial stewardship (AMS), and hospital-level outcomes in a tertiary paediatric hospital. <b>Methods</b>: This study was a retrospective hospital-wide ecological time-series at the Children's Memorial Health Institute. Annual aggregate data: 2011-2024 for screening, colonisation, and healthcare-associated infections (HAIs) with alert pathogens; 2016-2024 for antibiotic consumption (ATC J01, systemic antibacterials). Process indicators: number of screening tests and alcohol-based hand rub (ABHR) consumption per 1000 patient-days (PD). Outcomes: colonisations/HAIs per 1000 PD and defined daily doses (DDD) per 1000 PD overall and by class. Trends used linear regression and Spearman's rank correlation. <b>Results</b>: Screening intensity increased from 39 to 150/1000 PD (slope +8.3/year; R² = 0.90; <i>p</i> < 0.001). Detected colonisation rose (2.5 → peak 8.05/1000 PD in 2023; slope +0.39; R² = 0.81; <i>p</i> < 0.001), while multidrug-resistant-organism (MDRO)-attributable HAIs remained low/stable (0.27-0.62/1000 PD; slope -0.014; <i>p</i> = 0.023). ABHR consumption increased from 26.1 to 78.0 L/1000 PD in 2020 (<i>p</i> < 0.001) and partially normalised to 60.0 in 2024 (>2 × baseline). Overall ATC J01 showed no long-term linear trend (~278-356 DDD/1000 PD; +2.57/year; <i>p</i> = 0.46), but class mix shifted: carbapenems, fluoroquinolones, and amoxicillin-clavulanate decreased; third/fourth-generation cephalosporins, piperacillin/tazobactam, and glycopeptides increased. <b>Conclusions</b>: In this tertiary paediatric setting, expansion of risk-based admission screening and sustained implementation of horizontal IPC measures were accompanied by increased detection of colonisation with alert pathogens, while MDRO-attributable HAIs remained low and stable at the hospital level. Over the same period, AMS activity coincided with a redistribution in antibiotic class use without a clear long-term reduction in total antibiotic consumption. These hospital-level findings are descriptive and hypothesis-generating; causal inference is limited by the ecological study design, and the heterogeneous, multispecialty structure of a tertiary paediatric centre.