Pseudomonas Bacteremia in Pediatric Cancer Patients

Background: Despite availability of potent antimicrobial agents, Pseudomonas aeruginosa (P aeruginosa) continues to be a serious cause of bacteremia, with high rates of morbidity and mortality; but no available data to elucidate if non-aeruginosa strains of Pseudomonas constitute a similar problem or just bystanders. The aim of this study was to identify the relative frequency of Pseudomonas bacteremia, and to define its clinical impact in pediatric cancer patients receiving chemotherapy. Patients and Methods: Medical charts of pediatric cancer patients with Pseudomonas bacteremia, at National Cancer Institute were retrospectively reviewed during the period from January 1999 to December 2002. Risk factors, manifestations of infection, pattern of antibiotic susceptibility and outcome of cases with P aeruginosa and nonaeruginosa bacteremia were evaluated. Results: Over the period of the study, 72 cases of Pseudomonas bacteremia were recorded. P aeruginosa bacteremia represented 1.9% of the total number of positive blood cultures; whereas non-aeruginosa accounted for 4.5%. It was more common in patients with hematologic malignancies (80.6% versus 19.4% in solid tumors). The most common concomitant site of infection was the lower respiratory tract. The overall cure rate was 72% with no significant difference in adverse outcome between P aeruginosa and non-aeruginosa cases. The variables that were significantly associated with an unfavorable outcome were related to peripheral blood counts. Only a reduced monocyte count at day one was significantly associated with a bad prognosis, whereas at days 4 and 7 reduced absolute neutrophil count (ANC), monocyte, lymphocyte and platelet counts were all related to an adverse outcome. Conclusion: Pseudomonas sp. bacteremia still poses a great health hazard as regards morbidity and mortality in pediatric cancer patients receiving chemotherapy. Factors that can manipulate prolonged reduced cytopenias during intake of chemotherapy may be helpful to reduce adverse outcome of serious Pseudomonas sp. bacteremia in this population of patients.