French national epidemiology of bacterial superinfections in ventilator-associated pneumonia in patients infected with COVID-19: the COVAP study

Background: Description and comparison of bacterial characteristics of ventilator-associated pneumonia (VAP) between critically ill intensive care unit (ICU) patients with COVID-19-positive, COVID + ; and non-COVID-19, COVID-.

Methods: Retrospective, observational, multicenter study that focused on French patients during the first wave of the pandemic (March-April 2020).

Results: 935 patients with identification of at least one bacteriologically proven VAP were included (including 802 COVID +). Among Gram-positive bacteria, S. aureus accounted for more than two-thirds of the bacteria involved, followed by Streptococcaceae and enterococci without difference between clinical groups regarding antibiotic resistance. Among Gram-negative bacteria, Klebsiella spp. was the most frequently observed bacterial genus in both groups, with K. oxytoca overrepresented in the COVID- group (14.3% vs. 5.3%; p < 0.05). Cotrimoxazole-resistant bacteria were over-observed in the COVID + group (18.5% vs. 6.1%; p <0.05), and after stratification for K. pneumoniae (39.6% vs. 0%; p <0.05). In contrast, overrepresentation of aminoglycoside-resistant strains was observed in the COVID- group (20% vs. 13.9%; p < 0.01). Pseudomonas sp. was more frequently isolated from COVID + VAPs (23.9% vs. 16.7%; p <0.01) but in COVID- showed more carbapenem resistance (11.1% vs. 0.8%; p <0.05) and greater resistance to at least two aminoglycosides (11.8% vs. 1.4%; p < 0.05) and to quinolones (53.6% vs. 7.0%; p <0.05). These patients were more frequently infected with multidrug-resistant bacteria than COVID + (40.1% vs. 13.8%; p < 0.01).

Conclusions: The present study demonstrated that the bacterial epidemiology and antibiotic resistance of VAP in COVID + is different from that of COVID- patients. These features call for further study to tailor antibiotic therapies in VAP patients.