Trends of HAI and AMR in Italian intensive care units: findings from the SPIN-UTI network

INTRODUCTION: Healthcare-associated infections (HAIs) and antimicrobial resistance (AMR) pose a significant burden on Public Health. Although it is undeniable that the COVID-19 pandemic provoked challenges in routine clinical practices and surveillance, especially in intensive care units (ICUs), its impact on HAIs and AMR is still highly debated. The present analysis describes trends of HAIs and multidrug-resistant (MDR) microorganisms in Italian ICUs from 2006 to 2021. METHODS: According to the European Center for Disease Prevention and Control (ECDC) protocol, we used data on nearly 22,000 patients and 4,500 isolates from the “Italian Nosocomial Infections Surveillance in Intensive Care Units, SPIN-UTI” project. The study population consists of all patients admitted to Italian ICUs for more than 48 hours. Isolates of Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli and Klebsiella pneumoniae were classified as MDR if susceptible to at least one antimicrobial agent in three or more antibiotic classes. RESULTS: Overall, the incidence density of HAIs increased from 17.1 per 1,000 patient-days in 2006-2007 to 24.1 in 2020-2021. Part of this increase can be attributed to the increasing incidence density of pneumoniae (p < 0.001). Although the proportion of MDR microorganisms did not significantly change over the years, increasing trends were evident in the incidence density of MDR isolates for A. baumannii (from 1.3 to 3.2 per 1,000 patient-days) and K. pneumoniae (from 0.5 to 3.1 per 1,000 patient-days). By contrast, the proportion of methicillin-resistant Staphylococcus aureus decreased from 46.9% in 2006 to 30.2% in 2021 (p-<0.05). CONCLUSIONS: Our analysis shows an increasing trend in the incidence of HAIs and MDR microorganisms in Italian ICUs. This scenario has been surely worsened by the COVID-19 pandemic. It is still unclear, however, if the increasing incidence of AMR can be attributed to an overall increase in HAIs or to other causes. KEY MESSAGES: • In Italian ICUs, the incidence of HAIs and MDR microorganisms increased from 2006 to 2021. • Further studies should be conducted to estimate the impact of COVID-19 pandemic on HAIs and AMR.