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Updated: Dec 23, 2025
Constructing Mutants in Serotype 1 Streptococcus pneumoniae strain 519/43
Published on: September 11, 2020
Development of a mismatch amplification mutation assay to correctly serotype isolates of Streptococcus suis serotypes
Sonia Lacouture1,2,3, Masatoshi Okura1,2,3, Daisuke Takamatsu1,2,3
1Faculty of Veterinary Medicine, University of Montreal, Groupe de Recherche sur les Maladies Infectieuses en Production Animale and Swine and Poultry Infectious Diseases Research Center, Saint-Hyacinthe, Quebec, Canada (Lacouture, Corsaut, Gottschalk).
Abstract:
Streptococcus suis is one of the most important bacterial swine pathogens worldwide and is an emerging pathogen in humans. There are 29 serotypes, and serotyping, which is based on the antigenicity of the capsular polysaccharide (CPS) or on its coding genes, is often part of routine identification and provides further information regarding S. suis virulence and zoonotic potential. Serotypes 2 and 14 possess high zoonotic potential, and serotype 1/2 is the serotype most frequently isolated from diseased pigs in North America. PCR has replaced antibody-based techniques to perform serotyping. However, traditional PCR is not able to differentiate serotype 2 from 1/2 and serotype 1 from 14, given that the only difference in the cps loci of those serotype pairs is a nonsynonymous single-nucleotide polymorphism. We developed a mismatch amplification mutation assay (MAMA)-PCR that was able to correctly serotype 148 isolates previously known to be serotypes 1, 2, 1/2, or 14. This technique will be highly useful in animal and human health laboratories performing PCR serotyping of S. suis isolates.
Insights
A new Mismatch Amplification Mutation Assay (MAMA)-PCR accurately differentiates Streptococcus suis serotypes 1, 2, 1/2, and 14. This advancement improves identification of this important swine and human pathogen.
Area of Science:
- Veterinary Microbiology
- Bacteriology
- Molecular Diagnostics
Background:
- Streptococcus suis is a significant global swine pathogen with emerging zoonotic potential.
- Accurate serotyping of S. suis is crucial for understanding virulence and zoonotic risk, with serotypes 2 and 14 being highly zoonotic.
- Traditional PCR methods struggle to differentiate between specific S. suis serotypes (e.g., 2 vs. 1/2, 1 vs. 14) due to minor genetic variations.
Purpose of the Study:
- To develop a novel molecular method for precise differentiation of Streptococcus suis serotypes.
- To overcome the limitations of traditional PCR in distinguishing closely related S. suis serotypes.
- To provide a reliable tool for diagnostic laboratories handling S. suis identification.
Main Methods:
- Development and validation of a mismatch amplification mutation assay (MAMA)-PCR.
- Testing the MAMA-PCR assay on 148 previously characterized Streptococcus suis isolates.
- Comparison of MAMA-PCR results with known serotype designations.
Main Results:
- The developed MAMA-PCR successfully and accurately serotyped all 148 tested Streptococcus suis isolates.
- The assay effectively differentiated between serotypes 1, 2, 1/2, and 14, which are difficult to distinguish with conventional PCR.
- The MAMA-PCR demonstrated high specificity and accuracy for S. suis serotyping.
Conclusions:
- Mismatch Amplification Mutation Assay (MAMA)-PCR is a highly effective method for differentiating key Streptococcus suis serotypes.
- This molecular technique offers a significant improvement over traditional PCR for S. suis identification in diagnostic settings.
- The MAMA-PCR will enhance surveillance and epidemiological studies of Streptococcus suis in both animal and human health.
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