Lineages of Streptococcus equi ssp. equi in the Irish equine industry.
Abstract: Streptococcus equi ssp. equi is the causative agent of 'Strangles' in horses. This is a debilitating condition leading to economic loss, yard closures and cancellation of equestrian events. There are multiple genotypes of S. equi ssp. equi which can cause disease, but to date there has been no systematic study of strains which are prevalent in Ireland. This study identified and classified Streptococcus equi ssp. equi strains isolated from within the Irish equine industry. Results: Two hundred veterinary isolates were subjected to SLST (single locus sequence typing) based on an internal sequence from the seM gene of Streptococcus equi ssp equi. Of the 171 samples which successfully gave an amplicon, 162 samples (137 Irish and 24 UK strains) gave robust DNA sequence information. Analysis of the sequences allowed division of the isolates into 19 groups, 13 of which contain at least 2 isolates and 6 groups containing single isolates. There were 19 positions where a DNA SNP (single nucleotide polymorphism) occurs, and one 3 bp insertion. All groups had multiple (2-8) SNPs. Of the SNPs 17 would result in an amino acid change in the encoded protein. Interestingly, the single isolate EI8, which has 6 SNPs, has the three base pair insertion which is not seen in any other isolate, this would result in the insertion of an Ile residue at position 62 in that protein sequence. Comparison of the relevant region in the determined sequences with the UK Streptococcus equi seM MLST database showed that Group B (15 isolates) and Group I (2 isolates), as well as the individual isolates EI3 and EI8, are unique to Ireland, and some groups are most likely of UK origin (Groups F and M), but many more probably passed back and forth between the two countries. Conclusions: The strains occurring in Ireland are not clonal and there is a considerable degree of sequence variation seen in the seM gene. There are two major clades causing infection in Ireland and these strains are also common in the UK.
Publication Date: 2013-06-04 PubMed ID: 23731628PubMed Central: PMC3679875DOI: 10.1186/2046-0481-66-10Google Scholar: Lookup
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Summary
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This research paper focuses on studying and classifying the genotypes of Streptococcus equi ssp. equi, a bacteria that causes ‘Strangles’ disease in horses, prevalent in the Irish equine industry.
Objective of the Study
- The study is aimed at identifying and classifying the prevalent strains of Streptococcus equi ssp. equi within the Irish horse industry.
- It attempts to understand their genetic differences and their origin, direct impact in causing ‘Strangles’ disease and the degree of their severity.
Methodology
- The researchers analyzed a total of 200 veterinary isolates using Single Locus Sequence Typing (SLST), a genotyping technique based on the internal sequence of the seM gene in the bacterium.
- Successfully, 171 gave an amplicon and more precisely, 162 samples (137 Irish and 24 UK strains) gave robust DNA sequence data.
Results
- The isolates were divided into 19 groups based on the sequences. 13 groups had at least 2 isolates and 6 groups contained single isolates.
- There were 19 positions where a DNA single nucleotide polymorphism (SNP) occurs, meaning there was a variation at a single position in the genetic sequence among individuals. They also found one place where a 3 bp (base pair) insertion happened.
- All groups had 2-8 SNPs and of these, 17 would result in a change in the amino acid of the encoded protein.
- One of the isolates, EI8, had a unique 3 base pair insertion which resulted in the insertion of an Ile residue at position 62 in the protein sequence. This change was not seen in any other isolate.
Comparison with the UK’s Database
- They compared these results with the UK’s Streptococcus equi seM MLST database and found that two Irish groups (as well as two individual isolates) were unique to Ireland, and some probably originated from the UK.
- Furthermore, many strains likely passed back and forth between the two countries noting that the strains occurring in Ireland are not clonal and exhibit a high degree of sequence variation in the seM gene.
Conclusion
- Results from the study concluded that there are two major clades (groups of organisms evolved from a common ancestor) causing infection in Ireland, and these strains are also common in the UK.
- The study also reaffirms the fact that the disease strains are not clonal and differ significantly in their genetic sequences and origins.
Cite This Article
APA
Moloney E, Kavanagh KS, Buckley TC, Cooney JC.
(2013).
Lineages of Streptococcus equi ssp. equi in the Irish equine industry.
Ir Vet J, 66(1), 10.
https://doi.org/10.1186/2046-0481-66-10 Publication
Researcher Affiliations
- Department of Life Sciences, University of Limerick, Limerick, Ireland.
- Irish Equine Centre, Johnstown, Naas, Co. Kildare, Ireland.
- Irish Equine Centre, Johnstown, Naas, Co. Kildare, Ireland.
- Department of Life Sciences, University of Limerick, Limerick, Ireland ; Materials and Surface Sciences Institute, University of Limerick, Limerick, Ireland.
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Citations
This article has been cited 2 times.- Ma F, Guo X, Fan H. Extracellular Nucleases of Streptococcus equi subsp. zooepidemicus Degrade Neutrophil Extracellular Traps and Impair Macrophage Activity of the Host. Appl Environ Microbiol 2017 Jan 15;83(2).
- Abdul-Latif SAK, Yousif AA. Molecular study of Streptococcus equi isolated from horses with strangles in Iraq. Open Vet J 2025 Feb;15(2):731-737.
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