Extensive microbiological respiratory tract specimen characterization in critically ill COVID‐19 patients

Thomsen, Kim; Pedersen, Henrik Planck; Iversen, Susanne; Wiese, Lothar; Fuursted, Kurt; Nielsen, Henrik Vedel; Christensen, Jens Jørgen Elmer; Nielsen, Xiaohui Chen

Microbial co‐infections may contribute to the pulmonary deterioration in COVID‐19 patients needing intensive care treatment. The present study portrays the extent of co‐infections in COVID‐19 ICU patients. Conventional culture, molecular detections for atypical aetiologies, QiaStat‐Dx® respiratory panel V2 detecting 21 respiratory pathogens and ribosomal DNA genes 16S/18S amplicon‐based microbiome analyses were performed on respiratory samples from 34 COVID‐19 patients admitted to the ICU. Potential pathogens were detected in seven patients (21%) by culturing, in four patients (12%) by microbiome analysis and in one patient (3%) by respiratory panel. Among 20 patients receiving antibiotics prior to ICU admission, fungi (3 Candida albicans, 1 C. tropicalis, 1 C. dubliniensis) were cultured in 5 (15%) endotracheal aspirates. Among 14 patients who were antibiotic‐naive at ICU admission, two patients (6%) had bacterial respiratory pathogens (Staphylococcus aureus, Streptococcus pseudopneumoniae) cultured in their endotracheal aspirates. Microbiome analysis recognized four potential respiratory pathogens (3 Haemophilus influenza, 1 Fusobacterium necrophorum) isolated in samples from four other patients (12%). QiaStat‐Dx® respiratory panel V2 detected adenovirus in one patient (3%). The prevalence of pulmonary microbial co‐infections is modest among COVID‐19 patients upon admission to ICU. Microbiome analysis complements conventional microbial diagnostics in characterization of respiratory co‐infections.