Listeria monocytogenes septicemia in a Thoroughbred foal.

The research article reports a case of Listeria monocytogenes septicemia diagnosed in a young Thoroughbred foal leading to severe health issues like bronchopneumonia and eventual death despite intensive care and treatment efforts.

Case Presentation

• The Thoroughbred foal, only six days old, displayed symptoms such as fever, depression, diarrhea, and respiratory distress.
• Blood tests showed leukopenia (a decrease in white blood cells), neutropenia (a decrease in neutrophils, a type of white blood cell), degenerative left shift (a serious sign of systemic disease), and hyperfibrinogenemia (an increase in fibrinogen in the blood).
• Other blood parameters pointed towards metabolic acidosis (an excessive amount of acid in the blood), hypoxemia (low oxygen levels in the blood), hypocapnia (reduced carbon dioxide in the blood), hypoglycemia (low blood sugar levels), and hyponatremia (low sodium levels).

Treatment and Outcome

• Despite comprehensive care including aggressive therapeutic attempts to stabilize the foal’s health, the foal died within 12 hours of admission.
• A postmortem examination was conducted, which revealed the principal lesion to be severe bronchopneumonia present in both lungs.

Pathological Findings

• Further histopathology reports of the foal indicated severe bronchopneumonia. Borgpneumonia is an infectious disease of the lungs marked by widespread inflammation.
• The histopathology also showed evidence of necrotizing vasculitis, a severe form of inflammation of the blood vessels causing cell death.
• Additionally, intralesional coccobacilli were found, which are short rod-like bacterial organisms.

Microbiological Results

• The presence of septicemia, a life-threatening infection spreading through the bloodstream, was confirmed as blood cultures both collected at admission and just before death were positive for Listeria monocytogenes, a dangerous bacterium.
• In addition, cultures from the lung and liver taken at the time of necropsy (the post-mortem examination) were also positive for Listeria monocytogenes.
• Immunohistochemical examination of preserved tissues showed a high presence of Listeria monocytogenes antigen within the lung and in the blood vessels of multiple organs, confirming the widespread bacterial infection.