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

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. 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. 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. 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.