Risk Factors Associated with Community-Onset Infections Due to Multidrug-Resistant Organisms

<b>Background</b>: Antimicrobial Resistance (AMR) and the emergence of multidrug-resistant organisms (MDROs) represent major public health threats. Although traditionally linked to hospital-acquired infections (HAIs), MDROs are becoming gradually more prevalent in community-onset infections. <b>Objectives</b>: The objective of this study is to identify major risk factors associated with community-onset MDRO infections among patients admitted to the hospital. <b>Methods</b>: This is a retrospective study of patients admitted to the Internal Medicine Departments of the University General Hospital of Ioannina from July 2022 to August 2023 and had a microbiologically confirmed infection. Patients with HAIs were excluded. Data were extracted from both electronic and paper-based medical records and included variables such as demographics, baseline comorbidities, previous antibiotic use, previous hospitalizations, the type of MDRO and infection, and clinical outcomes. Statistical analysis included descriptive statistics, univariate analyses, and subsequently multiple binary regression models. Each regression model was adjusted for age and sex. <b>Results</b>: Our cohort included 125 participants with a mean age of 77.9 years, with the majority (58.4%) being female. The overall prevalence of MDRO infections was 43.2% (54/125). Notably, the presence of a permanent urinary catheter was associated with a nearly fourfold increase in the risk of community-onset MDRO infections (OR = 3.69; 95% CI: 1.35-10.05; <i>p</i> = 0.011), while prior hospitalization (OR = 3.33; 95% CI: 1.48-7.51; <i>p</i> = 0.004), the Charlson index score (OR = 3.08; 95% Cl: 1.1-8.68; <i>p</i> = 0.033) and previous antibiotic use (OR = 2.18; 95% CI: 0.98-4.84; <i>p</i> = 0.057) were also significant potential risk factors. <b>Conclusions</b>: The identification of key risk factors associated with community-onset MDRO infections in patients admitted to the hospital can assist clinicians in early stratification and rational selection of initial empirical antimicrobial treatment, support antimicrobial stewardship programs, promote targeted public health interventions, and encourage more judicious antibiotic use.