Bacteremia due to Capnocytophaga species during chemotherapy-induced neutropenia in patients with hematological malignancies.

The number of reported cases of infections due to Capnocytophaga species (spp.) is limited. We herein describe four cases developing bacteremia due to Capnocytophaga spp. during neutropenia after chemotherapy for hematological malignancies. At the onset of bacteremia, 3 of the 4 patients had oral mucositis, and 2 were co-infected with other bacteria. Two patients developed bacteremia while receiving fluoroquinolone as prophylaxis against bacterial infection. Bacteremia resolved with administration of antimicrobial agents in all patients and no recurrences were observed thereafter. The emergence of fluoroquinolone-resistant or beta-lactamase-producing Capnocytophaga spp. has recently been reported. Therefore, Capnocytophaga spp. could be causative pathogens in breakthrough and refractory infections under fluoroquinolone prophylaxis and empiric therapy, respectively, for febrile neutropenia. Capnocytophaga spp. should be recognized as one of the causative pathogens of febrile neutropenia. Furthermore, accumulation of cases and susceptibility data are required to establish an optimal treatment protocol.