Abstract
Necrotizing soft-tissue infection is associated with high mortality rate, and early surgical drainage and proper selection of antibiotics are critical for its treatment. Although many bacteria have been reported to cause it, Citrobacter koseri has not been reported as its causative agent yet. Here, for the first time, we present a case of Citrobacter koseri-induced necrotizing soft-tissue infection. A 77-year-old woman was admitted to our hospital for left forearm pain. Her medical history included diabetes mellitus, rheumatoid arthritis and steroid therapy. After diagnosing necrotizing soft-tissue infection, we immediately initiated surgical drainage. Piperacillin/tazobactam and clindamycin were administered. A culture of the wound yielded Citrobacter koseri. The wound improved in response to saline lavage and the antibiotics; a culture of the wound obtained after 25 hospital days turned negative. Thereafter, she was transferred to the orthopaedic ward for skin graft. Citrobacter koseri is a low-virulent agent and usually causes infection in an immunocompromised host. Since Citrobacter may be resistant to multiple antibiotics, anti-pseudomonal penicillin is recommended as the first-line therapy. Hence, to treat necrotizing soft-tissue infection in an immunocompromised host, we should select antibiotics that are effective against resistant gram-negative rods such as Citrobacter, as used in the present case.
