Increase of multidrug-resistant bacteria after the COVID-19 pandemic in a major teaching Hospital in Sicily (2018-2021)

Introduction: The COVID-19 pandemic has further highlighted the continuing threat of antimicrobial resistance (AMR) to global health and economic development. In the last two decades, AMR has raised increasing concern, with an estimated 4.95 million deaths globally due to bacterial AMR in 2019 alone. The aim of this study was to analyse the impact of the pandemic on the spread of multidrug-resistant organisms (MDROs) using data from the Hospital "P. Giaccone" in Palermo, comparing pre-pandemic and pandemic periods. Methods: This observational study involved adult patients who were discharged from the hospital between 01 January 2018 and 31 December 2021. Hospital Discharge Cards were linked with microbiological laboratory reports to assess MDRO isolations. SARS-CoV-2 positivity during hospitalisation was evaluated using the National Institute of Health surveillance system. Results: A total of 58 427 hospitalisations were evaluated in this study. Half the patients were aged over 65 years (N=26 984) and most admissions were in the medical area (N=31 716). During the hospitalisation period, there were 2681 patients (5%) with MDROs isolations, and 946 patients (2%) were positive for SARS-CoV-2. Multivariable analyses showed that during 2020 and 2021, there was a significantly increased risk of isolation of Staphylococcus aureus, Acinetobacter baumannii, and Klebsiella pneumoniae. Age, weight of the Diagnosis-Related Group (DRG), wards with higher intensity of care, and length-of-stay were associated with a higher risk of MDRO isolation. Conclusion: This study provides new insights into the impact of the COVID-19 pandemic on MDRO isolation and has important implications for infection control and prevention efforts in healthcare facilities. Age, DRG-weight, and longer hospital stays further increased the risk of MDRO isolation. Thus, it is imperative to improve and follow hospital protocols to prevent healthcare-associated infections.