Biochemical fingerprinting and ribotyping of isolates of Actinobacillus equuli from healthy and diseased horses.

The research investigates different techniques to distinguish between Actinobacillus equuli bacteria found in sick and healthy horses, however, it concludes that both ribotyping and biochemical fingerprinting could not distinguish between the two.

Understanding the Research Context

• The research circles around Actinobacillus equuli, a bacterium that naturally resides in horses, but can cause disease under certain conditions.
• To investigate the bacteria’s different strains, the scientists used 112 samples which include both clinical isolates (from sick horses) and isolates from the oral cavity of healthy horses.
• The researchers aimed to find distinguishing factors between disease-causing and non-disease causing strains.

Methodology Employed

• The researchers used two methods to analyze these bacterial samples: Ribotyping and Biochemical Fingerprinting.
• Ribotyping method involves the examination of rRNA genes. Each bacterial strain has unique rRNA patterns that serve as a “ribotype”. It’s a sensitive method to detect subtle genetic differences between bacterial strains.
• Biochemical fingerprinting involves analyzing which substrates (molecular compounds) the bacterium metabolizes and which it cannot. This method was conducted using a commercial system called ‘Pheneplate (PhP)’ which includes 48 different substrates.

Research Findings and Conclusion

• Ribotyping was found to be more sensitive than biochemical fingerprinting in detecting differences between isolates. Meaning, ribotyping could identify more subtle differences between the bacterial strains.
• However, the correlation between the results obtained from these two methods was poor.
• Unexpectedly, neither of these methods could distinguish the clinical isolates from the normal flora isolates effectively.
• Therefore, the researchers concluded that current methods may not be sufficient to properly classify and differentiate the different strains of Actinobacillus equuli.