Mycobacterium chelonae hand infection following ferret bite

Abstract

We present a case of hand infection caused by Mycobacterium chelonae. The patient was a 58-year-old woman with Type II diabetes mellitus and stage 4 chronic kidney disease. The infection occurred following a ferret bite and had not responded to oral antibiotics in the primary care setting. She developed signs of pyogenic flexor tenosynovitis of the index and middle fingers of her left hand. Laboratory parameters showed high C-reactive protein, raised erythrocyte sedimentation rate and leucocytosis. Ultrasound imaging confirmed the clinical diagnosis. Plain radiographs showed no osseous involvement. The infection was treated with surgical debridement and broad spectrum parenteral antibiotics. The intra-operative tissue specimens were initially negative on aerobic and anaerobic cultures. Following transient improvement of her inflammatory parameters and clinical signs, she developed a recurrence with added features of osteomyelitis of the index and middle finger metacarpal heads on repeat radiographs. A revision surgical debridement of the flexor tenosynovitis and osteomyelitis with specific long-term antibiotic cover has led to resolution of the infection. Extended cultures of the tissue specimens at the regional laboratory confirmed the causative organism to be M. chelonae. To our knowledge, this is the first reported case of M. chelonae infection resulting from a ferret bite. This case reminds us of the need for a high index of suspicion for infection with uncommon pathogens following animal bites, especially in patients with altered immune status.