Concomitant viral and bacterial pneumonia among patients in ICU with mechanical respiratory support

The use of mechanical ventilators in the intensive care unit (ICU) is often associated with higher risk of respiratory tract infections, including ventilator-associated pneumonia (VAP). Concomitant bacterial-viral infection was reported to worsen patient's clinical condition. This study evaluated the rate of concomitant bacterial-viral infections in patients with VAP and analyzed their clinical outcomes.

In this retrospective observational study 107 patients diagnosed with VAP and admitted in ICU with mechanical ventilator support between April 2018 and May 2019 in the Department of Respiratory Medicine, Dachang Hospital, Shanghai, China were included. 27 most commonly involved lower respiratory tract infection (LRTI) pathogens (bacteria and virus) and seven genetic markers of antibiotic resistance were detected and analyzed using Biofire® FilmArray® Pneumonia Panel plus (bioMérieux SA, Paris, France).

Of the 107 patients, 45 (42.1%) patients had bacterial infection alone (bacterial group), 26 (24.3%) had virus infection alone (viral group) and 24 (22.4%) patients had concomitant bacterial-viral infection (mixed group). Sixty-nine (64.5%) and 50 (46.7%) patient samples were positive for bacterial (bacterial and mixed groups) and viral (viral and mixed groups) detection, respectively. Streptococcus pneumonia (11.2%) and Influenza A (17, 15.9%), were the predominantly identified bacterial and viral species. The blaCTX-M (21.5%) was the predominant resistance gene detected. Twenty-four (22.4%) patients were positive for concomitant bacterial-viral infection; Staphylococcus aureus and Influenza A were the most common bacterial-viral combination identified.

Concomitant bacterial-viral infection was higher compared to previously published studies and the increased duration of mechanical ventilation was associated with increased disease severity.