Actinobacillus and Pasteurella species isolated from horses with lower airway disease.

This research article studies the correlation between certain species of Actinobacillus and Pasteurella bacteria isolated from horses, and the occurrence of lower airway disease. It indicates that the presence of these organisms, particularly A. suis-like bacteria, A. lignieresii, and A. equuli, might be associated with the development of lower airway inflammation in horses.

Research Methodology

• The researchers sampled 73 bacterial isolates from 65 horses. These horses had varying degrees of lower airway disease – some had clear symptoms while others showed no symptoms at all.
• The collection of samples was analysed to identify the specific types of bacteria present.
• The researchers compared the incidence of lower airway disease with the bacterial species isolated.

Key Findings

• More than 50% (37 out of 73) of the bacterial isolates were identified as Actinobacillus equuli.
• Smaller proportions were identified as A suis-like (17.8%), Pasteurella pneumotropica (11%), A lignieresii (8.2%), P haemolytica (6.8%) and P mairii (5.5%).
• The association of lower airway disease was highly significant with A suis-like bacteria and A lignieresii.

Implications of the Research

• The research suggests that various species of the bacteria Actinobacillus and Pasteurella are present in the lower airways of horses.
• A significant proportion of these bacteria falls under the Actinobacillus category, notably A equuli which constituted more than half of the bacterial isolates.
• Lower airway inflammation in horses was significantly associated with the bacteria A suis-like and A lignieresii, although these made up a small portion of the total bacterial isolates.
• Due to a large proportion of the bacteria being A equuli, researchers suggest that it could also be playing a substantial role in the onset of lower airway disease, although further research is needed to corroborate this theory.