Clostridium perfringens type A myonecrosis in a horse in Korea.

A 13-year-old male thoroughbred horse in Korea suffered from acute hemorrhagic myonecrosis, an extreme muscular inflammation, and ultimately died of acute respiratory failure caused by toxins secreted by a bacterial infection, Clostridium perfringens type A.

Case Presentation

• The research starts with a case presentation of a 13-year-old male thoroughbred horse in Korea diagnosed with an acute hemorrhagic myonecrosis. Myonecrosis is a condition in which the muscle tissue dies due to insufficient blood supply, and hemorrhagic means there was extreme bleeding.
• Complications rose when severe inter- and intrafascicular edema and hemorrhage ensued within the horse’s right gluteal area. Edema refers to fluid buildup that causes swelling, in this case, within the fascicles or muscle fibers. Hemorrhage refers to heavy bleeding.

Progression of the Disease and Post-Mortem Analysis

• Once the muscular and fascicular changes eventually subsided, the horse developed an acute respiratory problem. The lung was extensively bleeding, presenting a histological image of diffuse severe hemorrhage with mild neutrophilic infiltration, indicating a response to an infection or inflammation.
• Ultimately, the horse’s death was attributed to acute respiratory failure, which was hypothesized to occur secondary to a toxaemic event, that is, the presence of toxins in the blood.

Identification of Causative Agent

• The researchers were able to isolate Clostridium perfringens type A from the muscle and the lung. The bacterium is known for its ability to secrete alpha and beta2 toxins, which are assumed to have caused the toxic event that led to the horse’s acute respiratory failure.
• The definitive diagnosis was based on light microscopic examination, bacterial toxinotyping (identifying the toxins produced by the bacteria), and toxin genotyping (identifying the genes responsible for producing toxins). All these techniques were applied to samples obtained from the muscle and the lung lesions, and consistently pointed towards Clostridium perfringens type A.

Antimicrobial Susceptibility

• The researchers also tested the bacterial isolates for susceptibility to various antimicrobial agents to gather more data which could be useful in the development of treatment strategies in the future.