Characteristics, risk factors and outcomes of adult cancer patients with extensively drug-resistant Pseudomonas aeruginosa infections.

OBJECTIVE: To evaluate the characteristics and outcomes of cancer patients with extensively drug-resistant (XDR) Pseudomonas aeruginosa infections. METHODS: This was a retrospective cohort of P. aeruginosa infections in cancer patients in Crete, Greece. Patients were followed until discharge. Mortality, predictors of mortality and risk factors for XDR P. aeruginosa infection were studied. RESULTS: Ninety seven episodes (89 patients) of P. aeruginosa infections (52 with bacteremia) were included in the study. In 22 cases, the infection was due to XDR isolates. All XDR isolates were susceptible to colistin and variably resistant to almost all other antibiotics. The multivariate analysis showed that the independent risk factors for XDR P. aeruginosa infection were hematologic malignancy (OR 40.7, 95 % CI 4.5-367.6) and prior fluoroquinolone use (OR 11.0, 95 % CI 2.0-60.5); lymphopenia was inversely associated with XDR infections (OR 0.16, 95 % CI 0.03-0.92). Mortality was 43 %; infection-related mortality was 24 %. Bacteremia (OR 8.47, 95 % CI 2.38-30.15), infection due to XDR isolates (OR 5.11, 95 % CI 1.15-22.62) and age (OR 1.05, 95 % CI 1.00-1.09) were independently associated with mortality. CONCLUSION: Mortality in cancer patients with P. aeruginosa infections was high. Infection due to XDR isolates was independently associated with mortality.