Background and Objective:
The pandemic has overwhelmed healthcare systems worldwide. Simultaneously, the rise in multi-drug resistant organisms (MDRO) continues to threaten global health through significant morbidity, mortality, and global economic loss. This study aims to analyze the impact of the pandemic on the spread of some specific MDRO and define the differences between the pre-pandemic and pandemic period.

Methods:
This is an observational study that included adult patients discharged from the University Hospital of Palermo from 01/01/2018 to 31/12/2021. Hospital Discharge Cards of the recruited study patients were linked with reports from the microbiological laboratory to evaluate MDRO isolations. For each patient the SARS-CoV-2 positivity during the hospitalization was evaluated by consulting the surveillance system of the National Institute of Health. The contribution of several risk factors associated with the presence of MDRO was analyzed through logistic regression analysis. 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%) who tested positive for SARS-CoV-2. No statistical difference was found in the prevalence of MDRO in COVID-19 and non-COVID-19 patients. In the multivariable analyses, during 2020 and 2012 there was a statistically significant increased risk of isolation of the following MDRO: Staphylococcus Aureus, Acinetobacter Baumannii, and Klebsiella Pneumoniae. Age, DRG-weight, and length-of-stay were associated to a higher risk of MDRO isolation.

Conclusion:
In the study period there was an increasing trend of some MDRO isolations, even more so during the pandemic period. However, SARS-CoV-2 positivity did not impact the risk of contracting MDRO. It is imperative to improve and follow hospital protocols to prevent healthcare-associated infections.