Bacteremia due to Stenotrophomonas maltophilia in patients with hematologic malignancies.

Predisposing factors, clinical characteristics, and antimicrobial treatment of 37 hematology patients with Stenotrophomonas maltophilia bacteremia who were seen at the department of hematology of the University La Sapienza (Rome) from 1987 to 1996 were evaluated. The results were compared with a control group of patients with Pseudomonas aeruginosa bacteremia. Profound neutropenia was more prolonged in the S. maltophilia group (P=.025), severe cellulitis occurred only in S. maltophilia-infected patients (11 [30%]; P=.0002), and the bacteremia presented as breakthrough infection in 56% of the cases due to S. maltophilia (vs. only 24% of those due to P. aeruginosa; P=.002). Acute mortality rates associated with S. maltophilia and P. aeruginosa bacteremia were 24% and 21%, respectively. In both groups, profound neutropenia and hypotension at the onset of bacteremia, duration of profound neutropenia during bacteremia, severity-of-illness score > or =4, and inappropriate antibacterial treatment were factors significantly associated with death. Most S. maltophilia isolates were resistant to aminoglycosides, beta-lactams, and ciprofloxacin. Cotrimoxazole and ticarcillin-clavulanic acid showed borderline activity. Prompt administration of in vitro-active antibiotics may improve the prognosis of S. maltophilia bacteremia, especially for immunocompromised patients, and novel drug combinations are needed for the treatment of severe infections.

Fusarium infections in patients with severe aplastic anemia: review and implications for management.

BACKGROUND AND OBJECTIVE: The prognosis of severe fungal infections, such as fusarium infections, in patients with aplastic anemia is directly related to the recovery of bone marrow functions. In this study, in vitro anti-Fusarium activity of granulocytes was investigated, the case of disseminated infection in a child with very severe aplastic anemia is reported, and implications for management of such infective complications are discussed. DESIGN AND METHODS: The in vitro efficiency of PMNL from three untreated, normal blood donors and from two G-CSF-treated WBC donors in contrasting the growth of the Fusarium sp strain isolated from the patient we present was measured by a 3H-glucose uptake inhibition assay and confirmed by microscopic examination. RESULTS: Basic growth inhibitory activity of unstimulated PMNL on Fusarium cells was significantly enhanced in the presence of GM-CSF in all three blood donors tested. In one of the two G-CSF-treated donors, in vitro efficiency of PMNL in contrasting the growth of the fungus increased notably after G-CSF treatment. We report the case of a 3-year-old girl with very severe aplastic anemia unresponsive to conventional immunosuppressant therapy who developed a disseminated fusarium infection. The child initially responded to liposomal amphotericin B and granulocyte transfusions from G-CSF stimulated donors. Subsequently she was given a cord blood stem cell transplantation but died of disseminated infection. INTERPRETATION AND CONCLUSIONS: Including the present case, there are only ten reports of invasive infections caused by the genus Fusarium in aplastic anemia patients and only two of the patients survived. In vitro data seem to suggest that in vivo treatment with rh-G-CSF could have a stimulatory effect on the anti-Fusarium activity of neutrophils. Despite the efficacy of granulocyte transfusions by G-CSF-stimulated donors in the temporary control of fusarium infection, treatment of the underlying hematologic disease is required to cure the infection in patients with severe aplastic anemia. Granulocyte transfusions by G-CSF-stimulated donors while awaiting bone marrow recovery following the blood stem cell transplant should be considered.