Introduction: COVID?19 is an infectious disease caused by the SARS?CoV?2 with varying mortality based on severity and comorbidities.

Aims: To evaluate the impact on mortality and hospital stay duration of bacterial and fungal infections in patients with severe COVID?19 in an ICU and general pulmonology ward setting.

Methods: We retrospectively analyzed patients hospitalized with COVID?19 in the Department of Pulmonology in University Hospital ?St. Marina?. Data regarding demographics, comorbidities, biological samples collected, hospital and ICU stay duration, ventilatory support was gathered.

Results:  The study population included 2197 patients admitted for hospital treatment due to COVID?19 in the period from June 2020 to January 2022. All biological samples acquired and sent for microbiological testing were evaluated with the ones classified as contaminations being excluded from the final analysis. The most prevalent bacterial pathogens isolated were Gram negatives ? Acinetobacter 7.42% (n=163), Klebsiella 2.28% (n=50), Pseudomonas 1.14% (n=25). The most common Gram positives were members of genus Staphylococcus 1.91% (n=42). Candida 5.78% (n=127) was the most prevalent fungal agent isolated followed by Aspergillus 0.18% (n=4). The statistical analysis showed significantly higher incidence of bacterial infections in ICU patients and those requiring ventilation compared to patients in the general ward. The infections were associated with higher mortality and hospital stay duration.

Conclusion: Within the analyzed patient population a high incidence of bacterial co-infections was observed. These co-infections seem to independently increase the risk for poor outcomes.