Clostridium septicum-associated myonecrosis in a dog: case report.

Necrotizing soft tissue diseases are severe, rapidly progressive infections characterized by tissue destruction and toxemia, often leading to death. Although common in livestock, myonecrosis caused by toxinogenic clostridial species is rarely reported in dogs. This study reports a case of myonecrosis in a male mongrel dog attacked by stray dogs, which subsequently developed a Clostridium septicum infection. The dog, prostrate and in contact with the ground, was brought for treatment two days post-attack, presenting multiple bite wounds, particularly on the pelvic limbs and scrotum, and a scrotal abscess. The condition progressed to toxemic shock, with extensive necrosis and emphysema in subcutaneous tissue and muscles. Due to clinical deterioration, euthanasia was performed. Postmortem findings revealed widespread edema, hemorrhage, and emphysema in the affected skeletal muscle and subcutaneous tissue of the pelvic limbs and scrotum, alongside moderate multifocal purulent exudate in the muscle fascia. Histological analysis identified myonecrosis with perimysium and subcutaneous tissue expansion due to hemorrhage, proteinaceous material, and emphysema. Suppurative infiltrates containing gram-positive, rod-shaped bacteria were present within the fascia. PCR analysis confirmed C. septicum in samples of affected skeletal muscle. This case highlights the importance of early diagnosis and management of traumatic infections in dogs, identifying bite wounds as entry points for clostridial pathogens and soil or saliva as spore sources. It contributes to understanding the pathogenesis and management of these infections in dogs, emphasizing their poor prognosis and the urgency of addressing clostridial myonecrosis.