Pulmonary bacterial infections in patients hospitalized for COVID-19: a retrospective observational study

Abstract

Backround During the COVID-19 pandemic, antibiotics use was very common. However, bacterial co/secondary infections with coronaviruses remain largely unknown, especially outside of intensive care. The aim of this study was to investigate the pulmonary bacterial infections characteristics associated with COVID-19 in hospitalized patients. Methods A retrospective monocentric observational study was conducted in Bichat hospital in France, between February 26 and April 22, 2020. All patients hospitalized in standard wards with COVID-19 (positive nasopharyngeal PCR and/or typical aspect on CT scan) and diagnosed with a pulmonary bacterial infection (positive bacteriological samples) were included. Bacteriological and clinical data were collected from the microbiology laboratories and the patient's medical records. Results Twenty-three bacteriological samples from 22 patients were positive out of 2075 screened samples (1.1%) from 784 patients (2.8%). Bacterial infection occurred with a median of ten days after COVID-19 onset. Diagnosis of pulmonary bacterial infection was suspected on the increase of oxygen requirements (20/22), productive cough or modification of sputum (17/22), or fever (10/22). Positive samples included 13 sputum cultures, one Film Array® on sputum, one bronchoalveolar lavage, six blood cultures and two pneumococcal antigenuria. The most frequent bacteria were Pseudomonas aeruginosa (6/23), Staphylococcus aureus (5/23), Streptococcus pneumoniae (4/23), Enterococcus faecalis (3/23) and Klebsiella aerogenes (3/23). No Legionella antigenuria was positive. Four out of 496 nasopharyngeal PCR (0.8%) were positive for intracellular bacteria (two Bordetella pertussis and two Mycoplasma pneumonia). Conclusions Pulmonary bacterial secondary infections and co-infections with SARS-CoV-2 are uncommon. Antibiotic use should remain limited in the management of COVID-19.