Incidence, microbiology, and mortality of ventilation-associated pneumonia in a large Italian cohort of critically ill patients: results from the PROSAFE project

Objectives: Despite preventive measures, ventilator-associated pneumonia (VAP) remains the most common healthcare-associated infection in the intensive care unit (ICU). VAP's striking incidence and impact are a leading cause of morbidity and prolonged ICU stay. This study focused on the characteristics and outcomes of patients diagnosed with ICU-acquired VAPs in Italian ICUs. Methods: Data were drawn from the PROSAFE network, a prospective multicentric observational project conducted across 192 Italian ICUs (2014–2023). Clinical data were recorded following the European Centre for Disease Prevention and Control VAP definitions. The incidence rate was estimated, and multivariable logistic regression identified ICU mortality risk factors. Results: The patients admitted to the included ICUs were 402 085. Among 122 430 classified at risk for VAP because of invasive mechanical ventilation (IMV) ≥48 hours, a total of 11 978 VAP cases were identified, corresponding to a prevalence of 9.8%. The incidence rate of VAP was 10.47 cases per 1 000 ventilator days (95% CI: 10.28–10.66). Patients with VAP exhibited prolonged ICU stays (median: 23 days, Q1–Q3: 15–36) and high mortality (30.0%). Microbiological profiling of VAP identified Pseudomonas spp. (21.0%), Staphylococcus aureus (20.2%), and Klebsiella spp. (20.1%) as the predominant pathogens. The logistic regression showed that older age, chronic liver and kidney diseases, multidrug-resistant organisms, and Acinetobacter spp. aetiology and duration of ICU stay before VAP were significantly associated with higher mortality. Discussion: While confirming the overall high mortality of patients undergoing IMV, our findings highlight the significantly prolonged ICU stay in VAP patients, and the influence of multidrug-resistant organisms on VAP-related mortality. These insights emphasize the necessity for effective and timely preventive strategies, as well as the early identification of VAP aetiology.