Risk factors of septic shock in patients with hematologic malignancies and Pseudomonas infections.

Pseudomonas is a clinically significant and opportunist pathogen, usually associated in causing high mortality nosocomial infections. The aim of this study was to determine the risk factors associated with septic shock in patients diagnosed with hematologic malignancies and Pseudomonas infections. A total of 80 Pseudomonas isolates (77 Pseudomonas aeruginosa) were collected from 66 patients aged 2-64 years: 52 with acute leukemia (79%), 7 with lymphoma (10.5%), and 7 with other hematologic disorders (10.5%), between 2001 and 2009. The median age of the patients was 30 years. Isolates were collected mostly from bloodstreams (45%) and skin lesions (31.5%). The median time for microbiologic documentation was 8 days (range 0-35 days) from onset of neutropenia. At least 11 patients (16.6%) had recurrent (≥2) infections. The clinical symptoms observed were skin lesions (34%), diarrhea (20%), isolated fever (18%), and respiratory symptoms (14%). The isolates tested were found resistant to piperacillin/tazobactam (43%), ceftazidime (31%), imipenem-cilastatin (26%), ciprofloxacin (25%), and amikacin (26%). Septic shock occurred in 16.2% of episodes (13/80). Crude mortality due to septic shock occurred in 19.6% of patients (13/66). The median time for response to antibiotic therapy in the remaining 80.4% of patients (53/66) was 2.5 days. Univariate analysis revealed that factors associated with septic shock were: fever for ≥3 days in patients on antibiotic therapy (P = 0.019), serum lactate >5 mmol (P = 0.05), hemoglobin level <50 g/l (P = 0.042), hypoproteinemia <50 g/l (P = 0.01), procalcitonin >10 ng/ml (P = 0.031), and hypophosphatemia (P = 0.001). Multivariate analysis revealed that hypophosphatemia (P = 0.018), hypoproteinemia (P = 0.028), and high serum lactate (P = 0.012) are significant factors, independently associated with increased risk of septic shock in patients with hematologic malignancies and Pseudomonas infections.