Most evidence on mortality related to ventilator-associated pneumonia (VAP) and ventilator-associated tracheobronchitis (VAT) comes from general intensive care units (ICUs), with limited data on critically ill oncology patients. This study aimed to characterize the microbiologic profile and resistance patterns in an oncology hospital and to assess their impact on 14-day mortality.

Retrospective analysis of VAP and VAT cases in an oncology ICU in Brazil (January to December 2024), evaluating bacterial frequencies, multidrug-resistant organisms, and mortality. The chi-square test was used to assess the association of multidrug resistance (MDR) and sample type (blood or respiratory secretion) with mortality.

Among 85 ICU patients, VAT was more frequent (59%) than VAP (41%). Most were male (60%), with a median age of 61 years, and had solid tumors (85%), mainly lung and head-and-neck cancers. Of 109 samples, Pseudomonas aeruginosa (27%), Klebsiella pneumoniae (20%), and Stenotrophomonas maltophilia (17%) were the most common pathogens. MDR rates were particularly high in Acinetobacter baumannii (82%). The same microorganisms were isolated from blood and respiratory tract in four patients. Patients infected with S. maltophilia, Acinetobacter spp., Serratia marcescens, P. aeruginosa, and K. pneumoniae had longer hospital stays, with median durations >10 days. Device use was also prolonged in patients with infections due to S. marcescens, K. pneumoniae, and Acinetobacter spp., with median device duration >7 days. Overall 14-day mortality was 55%. MDR was not associated with mortality (p = 0.3), but infections with positive blood cultures were associated with significantly higher mortality (86% vs. 49%; p = 0.012).

This study provides valuable information on the microbiologic profile of patients with VAP and VAT in an oncology ICU and its impact on mortality. Mortality was not associated with MDR, possibly reflecting the high baseline risk due to underlying onco-hematologic conditions. However, patients with positive blood cultures had significantly higher mortality, suggesting a more invasive infectious process.