Optimization of Conditions for The Multiplex PCR for Diagnostics of Horse Strangles with Subspecies Differentiation of Streptococcus Equi Subsp Equi
Authors: Berdimuratova K.T., Makhamed R., Shevtsov A.B.
Journal: Eurasian Journal of Applied Biotechnology
Summary
# Editorial Summary: Multiplex PCR for Equine Strangles Diagnosis Streptococcus equi subspecies equi causes strangles, one of the most contagious respiratory diseases in horses, yet field diagnosis has traditionally relied on culture methods that are slow and sometimes unreliable. Berdimuratova and colleagues optimised a multiplex PCR protocol with electrophoretic detection capable of identifying and differentiating S. equi subsp. equi from the closely related S. equi subsp. zooepidemicus in a single reaction, addressing a significant diagnostic challenge given that zooepidemicus can contaminate samples or complicate interpretation. The assay demonstrated high specificity with no cross-reactivity to related streptococci or environmental flora, whilst achieving detection limits of 66 genomic copies (152 femtograms) for subsp. equi and 132 copies (305 femtograms) for subsp. zooepidemicus—sensitivity well below clinically relevant thresholds. For practitioners, this development offers potential for rapid, definitive laboratory confirmation of strangles outbreaks and accurate subspecies identification within hours rather than days, enabling faster quarantine decisions and targeted management on affected yards. Implementation would depend on local laboratory access and validation, but represents a valuable advancement for equine disease surveillance and outbreak control protocols.
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Practical Takeaways
- •A reliable multiplex PCR diagnostic tool is now available for rapid, sensitive identification of strangles-causing organism with subspecies differentiation in laboratory settings
- •The high sensitivity (detection at 66-132 genomic copies) suggests this test could identify infections at early stages when bacterial load is low
- •The lack of cross-reactivity means this test is specific to Streptococcus equi and won't produce false positives from other common equine pathogens or environmental bacteria
Key Findings
- •Multiplex PCR protocol successfully identifies and differentiates S. equi subsp. equi from S. equi subsp. zooepidemicus in a single reaction with high specificity
- •Detection limit for S. equi subsp. equi was 66 genomic copies (152 fg) and for S. equi subsp. zooepidemicus was 132 genomic copies (305 fg)
- •PCR protocol shows no cross-amplification with closely related microorganisms, saprophytic microflora, or other bacterial pathogens