[Bacteremia in hematological malignant disorders]

Abstract

Background: Bacteremia frequently complicates cytostatic treatment of hematological malignancies. Initial antibiotic treatment is chosen empirically before the results of cultures are available. Rational choices depend on updated knowledge of microbial resistance patterns. We have examined microorganisms in blood cultures over a 10-year period and compared them with the preceding 5-year period.

Material and methods: We analyzed isolates from blood cultures in patients with a hematological malignant disorder treated in the Hematology Unit, St. Olavs Hospital during the years 1995 - 2005.

Results: We found 373 isolates and 322 episodes of bacteremia in 225 patients. Most patients had acute leukemia or myeloma, with neutropenia after cytostatic treatment. The dominating pathogens were Escherichia coli (20 %), coagulase-negative staphylococci (13 %) and alpha-haemolytic streptococci (10 %). Enterococcus infections seem to occur more frequently and were associated with a high mortality. Gram-negative organisms constituted 48 % and gram-positive organisms 48 % of the isolates. About 3 / 4 of the patients had infections with penicillin-resistant bacteria. There was a low prevalence of organisms resistant to aminoglycoside. Acute leukemia patients with bacteremia had a 30-days all-cause mortality of 10.3 %.

Interpretation: We found small changes in the pattern of pathogens and antibiotic resistance over time. The rates of antibiotic resistance were favorable compared to other European countries. The mortality rate seems to be unchanged and acceptable. Penicillin G and aminoglycoside can still be considered as first-line treatment for suspected bacteremia in neutropenic patients in Norway.