Two techniques for detection of antibodies against Corynebacterium (Rhodococcus) equi in horse sera.

This study presents two techniques for detecting antibodies against a bacterial substance in horses. The researchers tested both methods on different samples and found the first technique to be more effective.

Methodology

The research outlined the development and testing of two techniques to detect the presence of antibodies against a substance produced by Corynebacterium (Rhodococcus) equi, a bacteria common in horses, called equi-factor.

• The first technique involved testing serum samples from horses against the native equi-factor. This factor was produced by growing C. equi on an agar medium. A positive response in this test was indicated by the formation of precipitation lines.
• The second technique was based on the neutralisation of the equi-factor which was first thoroughly cleaned out (prepurified). If present, the antibody would halt the equi-factor’s ability to synergise with staphylococcal beta toxin that causes red blood cell lysis (hemolysis). Basically, it inhibits the damaging effect caused by the synergy of both substances.

Testing and Results

The researchers subjected 125 serum samples collected from horses of varying ages and from different locations with a history of C. equi infections. The results varied across the two techniques.

• The first technique noted a 65.6% positive detection rate.
• On the other hand, the second method yielded a 40% rate of positive cases.

This suggests that the first technique, testing directly against the equi-factor, was more effective at detecting antibodies against C. equi in horse sera.