Increased mortality and Acinetobacter baumannii predominance despite stable healthcare-associated infection rates during the COVID-19 pandemic

BACKGROUND: Coronavirus disease 2019 (COVID-19), first identified in Wuhan, China, in December 2019, rapidly evolved into a global pandemic with substantial morbidity and mortality. Severe COVID-19 cases, particularly those with pneumonia requiring intensive care unit (ICU) admission, posed significant challenges for healthcare systems. This study aimed to evaluate and compare healthcare-associated infections (HAIs) developing in the ICU during the pre-pandemic and pandemic periods. METHODS: This retrospective observational study was conducted at Sakarya Yenikent State Hospital, a secondary-care hospital with 50 ICU beds. Active surveillance data collected by the infection control team were analyzed for two periods: pre-pandemic (May 2018-February 2020) and pandemic (March 2020-December 2021). The number of ICU patients, patient-days, HAI rates, causative microorganisms, antimicrobial resistance patterns, and mortality rates were compared between periods. Statistical analyses were performed using Epi Info™ version 7.2.5.0, with p < 0.05 considered statistically significant. RESULTS: A total of 1,840 patients (16,572 patient-days) in the pre-pandemic period and 2,119 patients (12,460 patient-days) in the pandemic period were followed. Mortality significantly increased during the pandemic period compared to the pre-pandemic period (40.96% vs. 24.94%, p = 0.00001). Although the overall HAI rate did not differ significantly between periods (3.26% vs. 2.73%, p = 0.333), Although the overall HAI rate did not differ significantly between periods (3.26% vs. 2.73%, p = 0.333), HAI density was higher during the pandemic. Notably, Acinetobacter baumannii-related HAIs increased significantly during the pandemic period (58.89% vs. 35.00%, p = 0.016), while distributions of other pathogens remained similar. Antimicrobial resistance patterns were more pronounced during the pandemic period. CONCLUSION: Despite similar HAIs rates, in-hospital mortality increased during the pandemic. This was accompanied by higher disease severity, reflected by increased cardiopulmonary resuscitation rates, and a shift toward Acinetobacter baumannii infections. Although mortality was high among COVID-19-positive patients, COVID-19 status was not an independent predictor. Overall, worse outcomes during the pandemic were associated with increased disease severity and pathogen distribution rather than changes in HAI incidence. CLINICAL TRIAL NUMBER: Not applicable.