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. This study aims to analyze the impact of the pandemic on the spread of multi-drug 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 discharged from the hospital between 01/01/2018-31/12/2021. Hospital Discharge Cards were linked with microbiological laboratory reports to assess MDRO isolations. SARS-CoV-2 positivity during hospitalization was evaluated using the National Institute of Health's surveillance system. Results This study evaluated 58,427 hospitalizations, where half of the patients were over 65 years old (N=26,984) and most admissions were in the medical area (N=31,716). During the hospitalization period, the isolated MDRO were 2,681(5%), whereas there were 946 subjects (2%) positive for SARS-CoV-2. In the multivariable analyses, during 2020 and 2021 there was a significant 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 to a higher risk of MDRO isolation. Conclusion Our 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 increase the risk of MDRO isolation. Thus, it is imperative to improve and follow hospital protocols to prevent healthcare-associated infections.