Comparison of garenoxacin with levofloxacin as antimicrobial prophylaxis in acute myeloid leukemia

Levofloxacin is widely used as antimicrobial prophylaxis against high-risk chemotherapy-induced neutropenia. Garenoxacin, a fluoroquinolone developed in Japan, shows a stronger in vitro antimicrobial activity against Gram-positive bacteria than levofloxacin. We retrospectively analyzed high-risk patients with acute myeloid leukemia who were administered garenoxacin (n = 36) or levofloxacin (n = 120) during chemotherapy. We compared the profiles of infections between these fluoroquinolones. Febrile events occurred in 31 (86%) and 93 (78%) cases in the garenoxacin and levofloxacin group, respectively (P = 0.35). Bloodstream infections by Gram-positive bacteria were recorded in one (3%) case in the garenoxacin group and 25 (21%) cases in the levofloxacin group (P < 0.01). In contrast, bloodstream infections by Gram-negative microorganisms were identified in five (4%) cases in the levofloxacin group and eight (22%) cases in the garenoxacin group (P < 0.01). These results indicate that there may be substantial differences in the antimicrobial spectrum between different fluoroquinolones. Although there are several biases due to rather small sample size and the retrospective nature, we should take the differences into consideration when we administer a prophylactic fluoroquinolone to a patient with hematological disease.