Pulmonary bacterial infections in adult patients hospitalized for COVID-19 in standard wards.

OBJECTIVES: During the COVID-19 pandemic, antibiotic use was very common. However, bacterial co-/secondary infections with coronaviruses remain largely unknown in standard wards. We aimed to investigate the characteristics of pulmonary bacterial infections associated with COVID-19 in hospitalized patients. METHODS: A retrospective monocentric observational study was conducted in Bichat hospital, 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 pulmonary bacterial infection (positive bacteriological samples) were included. Bacteriological and clinical data were collected from the microbiology laboratories and 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 within a median of 10 days after COVID-19 onset. Diagnosis of pulmonary bacterial infection was suspected on increase of oxygen requirements (20/22), productive cough or modification of sputum aspect (17/22), or fever (10/22). Positive samples included 13 sputum cultures, one FilmArray® assay on sputum samples, one bronchoalveolar lavage, six blood cultures, and two pneumococcal urinary antigen tests. 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 urinary antigen test was positive. Four out of 496 nasopharyngeal PCR tests (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.

Identification of group A streptococcal emm types commonly associated with invasive infections and antimicrobial resistance by the use of multiplex PCR and high-resolution melting analysis.

M/emm typing, based either on serotyping of the M protein or on sequencing of the emm gene, is a major tool for epidemiological studies of group A streptococci (GAS). In order to simplify M/emm typing, we designed two multiplex polymerase chain reaction (PCR) formats capable of identifying the most frequent GAS M/emm types involved in invasive infections and antimicrobial resistance. A heptaplex PCR procedure was first developed in a conventional format coupled with gel electrophoresis to identify emm types 1, 3, 4, 6, 12, 28, and 89, based on the size of the amplification products. The other method, designed to identify the same seven emm types, together with emm11, was based on a real-time PCR format coupled with high-resolution melting (HRM) analysis, allowing the rapid typing of large strain collections.