Prevalence of early bacterial co-infection in hospitalized patients with COVID-19 pneumonia: a retrospective study

BACKGROUND: Identification of bacterial co-infection is crucial in determining outcomes of patients with coronavirus disease 2019 (COVID-19) pneumonia. The present study aims to evaluate the prevalence and associated factors of early bacterial co-infection in patients with COVID-19 pneumonia. METHODS: The present study is a retrospective study. Patients with COVID-19 pneumonia, who were admitted to Siriraj Hospital between April 1 and August 31, 2021, were randomly enrolled and classified as the “Early bacterial co-infection” group, defined by an infection occurring within the first 48 hours after admission, and the “Unlikely early bacterial co-infection” group. RESULTS: A total of 245 patients were enrolled. The prevalence of early bacterial co-infection was 15.5%. Chest X-rays showed characteristic findings for COVID-19 pneumonia in 37.6%. The median Brixia chest X-ray scores and C-reactive protein levels were significantly higher in the Early bacterial co-infection group. The most common causative pathogens included Staphylococcus aureus, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. Patients with early bacterial co-infection had a significantly higher all-cause mortality compared to the Unlikely early bacterial co-infection group (P=0.012). The Charlson Comorbidity Index ≥4, high level of respiratory support, and mass-liked or diffuse opacities on chest X-rays were independent factors associated with the early bacterial co-infection. CONCLUSIONS: The prevalence of early bacterial co-infection in patients with COVID-19 pneumonia was low but it was associated with mortality. There is insufficient evidence to support the empirical use of antibiotics in these patients. A further prospective study is required to confirm the results of the present study.