Diabetes Mellitus and Multidrug-Resistant Gram-Negative Bacterial Infections in Critically Ill COVID-19 Patients: A Retrospective Observational Study

<b>Background:</b> Diabetes mellitus (DM) is an independent risk factor for severe SARS-CoV-2 infection and is linked to higher incidences of infections and adverse outcomes in patients with DM. This study examines the association between DM and multidrug-resistant Gram-negative bacteria (MDR-GNB) in critically ill, intubated COVID-19 patients in the intensive care unit (ICU) and evaluates mortality rates and clinical factors contributing to unfavorable outcomes. <b>Methods:</b> This retrospective observational study included intubated COVID-19 patients diagnosed with secondary infections due to MDR-GNB. Patients were treated for acute respiratory distress syndrome (ARDS) in a tertiary care university hospital ICU between October 2020 and February 2022. Collected data included demographics, comorbidities, medication, and laboratory parameters including blood tests and culture samples. <b>Results:</b> Among 416 COVID-19 patients, 112 (26.9%) had T2DM. Cultures from lower respiratory tract specimens revealed a significantly higher likelihood of isolating <i>Acinetobacter baumannii</i> in patients with DM (OR: 2.18, 95% CI: 1.40-3.40, <i>p</i> < 0.001), and DM is an independent predictor of isolation <i>Acinetobacter baumannii</i> in bronchial secretions of COVID-19 intubated patients (OR: 2.046, 95% CI: 1.256-3.333. <i>p</i> < 0.004). DM was not significantly associated with differences in length of stay (LOS) until discharge or death (HR: 0.76, 95% CI: 0.51-1.12, <i>p</i> = 0.16; HR: 0.91, 95% CI: 0.70-1.19, <i>p</i> = 0.50) or 28-day ICU mortality (OR: 1.12, 95% CI: 0.52-2.41, <i>p</i> = 0.77). Age was linked to an increased 28-day mortality risk in patients with DM (OR: 1.10, 95% CI: 1.02-1.18, <i>p</i> = 0.011). <b>Conclusions:</b> In critically ill intubated COVID-19 patients, DM emerged as a significant and independent predictor for the isolation of <i>Acinetobacter baumannii</i> from bronchial secretions, highlighting a key link between DM and specific multidrug-resistant pathogens, even though no broader association with MDR-GNB-related secondary infections was observed.