Background: The clinical and microbiological epidemiology of ventilator-associated pneumonia (VAP) is not well studied in intensive care units (ICUs) European wide. The European Clinical Research Alliance on Infectious Diseases (Ecraid), a warm-base clinical research network investigating infectious diseases, aimed to track the implementation of VAP prevention strategies and quantify the incidence, aetiology, and clinical outcome of VAP, across several European countries.

Methods: Overall, 25 ICUs from 11 European countries participating in Ecraid’s perpetual observational study prospectively enrolled adult patients with an expected length of invasive mechanical ventilation (IMV) of at least 48 h, between August 2022 and September 2024. VAP was defined according to the US Food and Drug Administration guidelines. Patients were followed until ICU discharge or 28 days after VAP diagnosis. Routine clinical and microbiological data were prospectively collected. Mortality was calculated using cumulative incidence functions.

Results: Of the 3,446 patients at-risk of VAP, 590 developed VAP (cumulative incidence: 17.1%, 95% CI 15.9%-18.4% and incidence rate per 1000 ventilator days: 18.6, 95% CI 17.1–20.1). Importantly, VAP cumulative incidence varied widely between countries recruiting at least 100 patients (range: 7.6% (Croatia)-29.6% (Romania)). Microbiological documentation was available for 359 (60.8%) VAP patients, predominantly showing Staphylococcus aureus (26.2%), Haemophilus influenzae (16.2%), and Pseudomonas aeruginosa (15.0%). Methicillin resistance was confirmed in 14 (18.2%) of 77 VAP cases due to S. aureus . Ceftazidime and carbapenem resistance for P. aeruginosa was reported in 10/46 (21.7%) and 8/47 (17.0%) cases, respectively. Cumulative incidence of ICU mortality was 34.2% (95% CI 30.4%-38.0%) among VAP patients versus 29.3% (95% CI 27.6%-30.9%) in non-VAP patients. The overall median IMV duration until first extubation was 17 days in VAP patients (including ventilation before and after diagnosis) versus 7 days for non-VAP patients. The most widely implemented VAP prevention measure was head-of-bed elevation (3207 patients, 93.1%); only 4 patients (0.1%) did not have any prevention measures implemented.

Conclusion: In European ICUs, there is a considerable and heterogeneous incidence of VAP, with methicillin susceptible S. aureus most frequently identified as a causative pathogen. VAP is associated with poor clinical prognosis, highlighting the need for better VAP prevention and management strategies.