Contagious equine metritis–use of gas liquid chromatography in identifying the causal agent.

The study examines the use of gas chromatography for identifying the microbe responsible for contagious equine metritis, a highly infectious bacterial disease in horses, by studying the fatty acid compositions of the bacteria. This method, the researchers found, provided precise identification of the bacteria, with a high degree of consistency among samples.

Methodology

• Scientists measured cellular fatty acid compositions of contagious equine metritis isolates and three reference Haemophilus equigenitalis cultures using gas chromatography, a method to separate and analyze compounds.
• The triggered chromatographic data was then normalized and standardized to generate Fatty Acid Methyl Ester (FAME) profiles.

Results

• The FAME profiles of the three reference strains showed minimal difference, each being identified by three major fatty acids: C 18:1, C 16:0 and 30H-C 14:0.
• They found that modifications in cultural conditions did not greatly impact the FAME profiles, indicating a degree of robustness to the method.
• The identification of laboratory test isolates using gas chromatography agreed with the assumptions based on currently recommended tests and were found to be superior to the confirmatory serological identification, a test that identifies bacteria based on their reaction with specific antibodies.
• The FAME profiles provided reliable identification even when the existing recommended serological procedures were not applicable.

Conclusions

• The research team suggests that gas chromatography be used as an add-on to the currently accepted bacterial identifying methods in diagnostic laboratories.
• This methodology could serve to increase the efficiency and reliability of diagnosing contagious equine metritis, given its proven consistency and precision.