Impact of Respiratory Coinfections on Outcomes of Pneumocystis jirovecii Pneumonia in Solid Organ Transplant Recipients

BACKGROUND: Pneumocystis jirovecii pneumonia (PCP) is a significant opportunistic infection in solid organ transplant (SOT) recipients. However, the impact of respiratory coinfections on outcomes in this population remains unclear. METHODS: We retrospectively analyzed 112 SOT recipients diagnosed with PCP from April 2018 to March 2024. Respiratory coinfections were defined as identification of significant pathogens in respiratory specimens within 3 days of PCP diagnosis. RESULTS: Among 112 SOT recipients with PCP, 50.0% required intensive care unit (ICU) admission, and the 30-day and 90-day mortality rates were 12.5% and 17.9%, respectively. Respiratory coinfections were identified in 46 patients (41.1%), including cytomegalovirus (CMV, 30.4%), bacteria (14.3%), and non-CMV viruses (13.4%). Bacterial coinfection was significantly associated with increased 30-day mortality (adjusted odds ratio [aOR], 5.27; 95% confidence interval [CI], 1.15-26.27; p = 0.03) and 90-day mortality (aOR, 4.84; 95% CI, 1.29-19.35; p = 0.02). CMV coinfection was independently associated with prolonged hospital stay (adjusted ratio, 2.42; 95% CI, 1.67-3.50; p < 0.001), higher ICU admission rates (aOR, 2.95; 95% CI, 1.04-9.03; p = 0.05), and increased need for mechanical ventilation (aOR, 3.01; 95% CI, 1.10-8.83; p = 0.04), but not with mortality. Non-CMV viral coinfection was associated with significantly increased odds of ICU admission (aOR, 19.03; 95% CI, 2.67-254.90; p = 0.01) and mechanical ventilation (aOR, 21.21; 95% CI, 2.96-298.12; p = 0.01), without a significant impact on mortality. CONCLUSION: In SOT recipients with PCP, bacterial coinfection was associated with higher mortality, while CMV and non-CMV viral coinfections were mainly associated with morbidity. Respiratory co-pathogens may indicate illness severity; whether pathogen-directed strategies can modify outcomes requires further study.