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 ECDC VAP definitions. The incidence rate (IR) 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 IR of VAP was 10.47 cases per 1,000 ventilation-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 Klebsiella spp. (22.2%), Pseudomonas spp. (22.4%), and Staphylococcus aureus (22.7%) 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 prior to VAP were significantly associated with higher mortality. Conclusions: These findings highlight the elevated mortality rates in VAP patients, the significantly prolonged ICU stay, and the influence of MDROs on VAP-related mortality. These insights emphasize the necessity for effective and timely preventive strategies, as well as the early identification of VAP aetiology.