Use of leukocytes as treatment for endometritis in mares experimentally infected with Streptococcus equi subsp. zooepidemicus.

The research examines the efficacy of various treatments for bacterial endometritis in mares, particularly those utilizing leukocytes. It concludes that while treatment did not significantly affect the time required for resistant mares to eliminate bacteria, using viable or lysed leukocytes associated with opsonizing factors reduced the time for bacterial elimination in susceptible mares.

Overview of the Research

• This study was aimed at exploring the effectiveness of different treatments for endometritis in mares, specifically those infected by Streptococcus zooepidemicus.
• The experiment involved 25 mares, out of which 20 were resistant, and 5 were susceptible to endometritis.
• All the mares showed clinical signs of endometitis post-infection and were put into one of five treatment groups. These included treatment with fresh leukocytes, frozen-thawed leukocytes, lysed leukocytes, recombinant human interleukin-8 (rhIL-8), or control.
• The treatment effects were categorized using a Latin square design and there was a minimum of a 14-day interval between each treatment.

Key Findings

• The results showed that the type of treatment used did not significantly impact the duration required for the resistant mares to eliminate the bacteria.
• The time required for the elimination of bacteria was similar in the susceptible mares when treated with either fresh or frozen leukocytes.
• While the time to eliminate bacteria didn’t significantly differ between the treatment with frozen versus lysed leukocytes, a significant difference was apparent between the mares treated with rhIL-8 and control.
• In the case of resistant mares, their inherent physical ability to clear the bacteria was likely responsible for bacterial elimination.
• For mares susceptible to endometritis, intrauterine infusions with viable or lysed leukocytes, with or without opsonizing factors, decreased the time required to eliminate the bacteria, suggesting that infusions with bactericidal effect (functional neutrophils and granules) were likely effective, leading to a quicker elimination of bacteria.

This study sheds light on the role and potency of different treatments for endometritis in mares which could guide future therapeutic approaches, especially with the utilization of leukocytes, in dealing with comparable infections.