Coenen, et al. (2021) defined the frequency of respiratory community-acquired bacterial co-infection in patients with COVID-19, i.e. patients with a positive SARS-CoV-2 PCR or a COVID-19 Reporting and Data System (CO-RADS) score ≥ 4, based on a complete clinical assessment, including prior antibiotic use, clinical characteristics, inflammatory markers, chest computed tomography (CT) results and microbiological test results.

The researchers'  retrospective study was conducted within a cohort of prospectively included patients admitted for COVID-19 in our tertiary medical centers between Jan. 3-6, 2020. A multidisciplinary study team developed a diagnostic protocol to retrospectively categorize patients as unlikely, possible or probable bacterial co-infection based on clinical, radiological and microbiological parameters in the first 72 hours of admission. Within the three categories, the researchers summarized patient characteristics and antibiotic consumption.

Among 281 included COVID-19 patients, bacterial co-infection was classified as unlikely in 233 patients (82.9%), possible in 35 patients (12.4%) and probable in three patients (1.1%). Ten patients (3.6%) could not be classified due to inconclusive data. Within 72 hours of hospital admission, 81% of the total study population and 78% of patients classified as unlikely bacterial co-infection received antibiotics.

COVID-19 patients are unlikely to have a respiratory community-acquired bacterial co-infection. This study underpins recommendations for restrictive use of antibacterial drugs in patients with COVID-19.

Reference: Coenen S, et al. Low frequency of community-acquired bacterial co-infection in patients hospitalized for COVID-19 based on clinical, radiological and microbiological criteria: a retrospective cohort study. Antimicrobial Resistance & Infection Control. Vol. 10, article number 155 (2021).