A case of necrotizing fasciitis caused by Bifidobacterium breve

Background: Bifidobacterium breve is an obligate anaerobic gram-positive bacillus mainly found in the gastrointestinal tract of human infants. Few cases of necrotizing fasciitis caused by B. breve have been reported. Case presentation: A 42-year-old Japanese man with type 2 diabetes mellitus, obesity, cellulitis of the back, and subcutaneous abscess of the right inguinal region presented with rapidly developing erythema, swelling and severe pain in the right inguinal region. Computed tomography showed widespread gas in the right leg region. Cultures of blood and a swab of the wound abscess grew gram-positive bacilli. Mass spectrography and 16 S rDNA analysis confirmed the gram-positive bacilli as B. breve. The patient recovered following extensive debridement and antibacterial therapy. Conclusion: Unidentified necrotizing fasciitis can be caused by B. breve, especially in compromised hosts.