Abstract
We report typhoid fever showing reduced susceptibility to fluoroquinolones treated successfully with tosufloxacin (TFLX) combined with cefotaxime (CTX). A 21-year-old Japanese man visited India and Nepal between June 10 and September 7, 2004, developed a high fever and diarrhea on August 30 while in Nepal. After returning to Japan and being seen elsewhere, he was transferred to our department. Laboratory findings on admission included thrornbocytepenia and elevated serum transaminase, but no Plasmodium spp. in blood smears. Salmonella Typhi was isolated from blood cultures, and the patient was diagnosed with typhoid fever. TFLX 300mg b. i. d. was administered, but the fever persisted. The S. Typhi strain isolated from the patient was resistant to nalidixic acid in vitro, so we added of CTX 4g/day i. v. to TFLX, resulting in good combined effect. The minimum inhibitory concentrations (MIC) of TFLX, CTX, and NA for S. Typhi thus isolated were 0.25μg/mL, 0.5μg/mL, and 256μg/mL. By calculating the fractional inhibitory concentration (FIC) index based on a checkerboad technique, we demonstrated in vitro synergism of TFLX with CTX. Combining of TFLX with CTX is thus expected to effectively treat typhoid fever with reduced susceptibility to fluoroquinolones.
