Abstract
Although anaerobic bloodstream infections (ABI) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) are rare, the mortality rate is high. In this retrospective study, we examined ABI episodes in 981 consecutive patients who underwent allo-HSCT at the National Cancer Center Hospital from January 2001 to October 2013. We identified 23 strains of anaerobes from 23 ABI episodes. Of these, 14 ABI episodes occurred before engraftment and 9 episodes occurred after engraftment. Fusobacterium sp. and Porphyromonas sp. were predominantly detected during the pre-engraftment period and were assumed to be derived from the oral cavity or upper intestinal tract. In contrast, Bacteroides sp. and Clostridium sp. were the frequently isolated anaerobes in the post-engraftment and were assumed to be derived from the lower intestinal tract. The presence of polymicrobial bacteremia was significantly associated with ABI episodes and was assumed to be derived from the lower intestinal tract. These results indicate the differences in clinical features of ABI between the pre- and post-engraftment periods and provide valuable information for the selection of appropriate antibiotics as an empirical treatment.
