Clinical Features, Etiology, and Outcome of Bacteremic Pneumonia in Cancer Patients.

Background: Current information regarding bacteremic pneumonia (BP) in cancer pts is scarce. We saught to analyze the clinical features, etiology, and outcomes of BP in this population.

Methods: All consecutive episodes of bacteremia in hospitalized adult cancer pts and hematopoietic stem cell transplant recipients (HSCT) were prospectively collected (Jan 2006 - Mar 2016). BP was defined as the presence of an acute respiratory illness and a pulmonary infiltrate on a chest radiograph in association with positive blood cultures.

Results: Of 1977 episodes of bacteremia in cancer pts, 154 (7.8%) were identified as BP. Seventy-nine (51.3%) pts had solid tumor and 20 (12.3%) were HCST recipients. Fourty-nine (31.8%) pts had neutropenia, and 56% had chronic advanced malignancy. Previous corticosteroids were observed in 47% of pts. The most frequent causative agent was Streptococcus pneumoniae (52.5%), followed by Pseudomonas aeruginosa (18.9%), and Haemophilus inflluenzae (6.3%). Among all Gram-negatives, 6 (10%) isolates were multidrug-resistant. Thirty-eight (24.7%) pts presented with septic shock, 18 (11.7%) required intensive care unit admission, and 9 (16.7%) underwent mechanical ventilation. Overall, 12 pts (7.8%) received inadequate empirical antibiotic therapy, of whom 9 (18.8%) pts died. 30-day and 48-hour case-fatality rates were 31.6% and 14.9%, respectively. Independent risk factors for 30-day case-fatality were chronic advanced malignancy (OR 3.3, 95% CI 1.1-9.9; p=0.026), corticosteroids (OR 3.3, 95% CI 1.2-9.2; p=0.017), and inadequate initial empirical antibiotic therapy (OR 6.6, 95% CI 1.2-35.5; p=0.027). Independent risk factors for 48-hour case-fatality were infection due to P. aerugionosa (OR 9.0, 95% CI 1.5-52.9; p=0.015) and Escherichia coli(OR 14.7, 95% CI 1.5-141.4; p=0.019), and inadequate initial empirical antibiotic therapy (OR 20.3, 95% CI 3.0-136.4; p=0.002).

Conclusion: BP in cancer pts is mainly caused by S. pneumoniae and P. aeruginosa. The emergence of antimicrobial resistance is of special concern. Case-fatality rates among pts with BP remain high, especially in pts with chronic advanced disease, with infection due to Gram-negatives, and in those who receive inadequate initial empirical antibiotic therapy.