Novel primers for the detection and differentiation of S. zooepidemicus and S. equi by PCR.

This study focuses on developing a rapid, reliable, and cost-effective test for differentiating between two closely related bacteria, S. zooepidemicus and S. equi, which are significant causes of equine diseases.

Article Background

• This research article deals with a bacterium named Streptococcus equi and its subspecies zooepidemicus (S. zooepidemicus). Both S. zooepidemicus and S. equi are associated with various horse diseases.
• Despite the different clinical signs exhibited by the two subspecies, both share approximately 97% DNA homology making their differentiation challenging.
• The goal of this research was to develop a commercially applicable test that can rapidly differentiate between these two bacterial subspecies.

Research Methodology

• The researchers looked to design a multiplex qPCR assay, a type of test that simultaneously measures multiple targets in a single reaction, based on the species-specific genes unique to S. zooepidemicus and S. equi. The genes targeted were sodA, seeH, and lacD.
• 300 clinical samples were screened using the newly developed test. The samples were divided evenly into positive samples for S. equi, positive samples for S. zooepidemicus, and tracheal wash samples negative for both bacteria. The results were then compared to existing diagnostic techniques.

Research Findings

• The results from the new assay showed a specificity of 98.0%, suggesting a high accuracy rate in differentiating between S. zooepidemicus and S. equi.
• The lowest detection limit was found to be between 10 and 100 copies per microliter. This suggests that the assay can effectively identify low-level infections that could potentially be overlooked via traditional culture methods.

Conclusion

• This research developed a qPCR assay that provides a reliable, quick, and cost-effective solution for identifying and differentiating between the S. zooepidemicus and S. equi bacteria.
• This assay is a potential alternative to current diagnostic techniques and is expected to be more sensitive and time-efficient.