Recombination Drives Genetic Diversification of Streptococcus dysgalactiae Subspecies equisimilis in a Region of Streptococcal Endemicity

2011

Genetic Diversification of Streptococcus dysgalactiae in India

Sample size: 181 publication 10 minutes Evidence: high

Author Information

Author(s): David J. McMillan, Santosh Y. Kaul, P. V. Bramhachari, Pierre R. Smeesters, Therese Vu, M. G. Karmarkar, S. Melkote Shaila, Kadaba S. Sriprakash

Primary Institution: Queensland Institute of Medical Research, Brisbane, Queensland, Australia

Hypothesis

How does genetic recombination affect the diversity of Streptococcus dysgalactiae subspecies equisimilis in endemic regions?

Conclusion

The study found that genetic recombination in endemic regions leads to a higher frequency of novel variants of Streptococcus dysgalactiae, some of which may have increased pathogenic potential.

Supporting Evidence

Indian SDSE isolates have unique sequence types compared to those from other regions.
The ratio of recombination to mutation in the Indian population is significantly higher than in non-endemic regions.
Recombination involving the emm-gene is more frequent than that involving housekeeping genes.
Three sequence types were found to be overrepresented in throat infection isolates.

Takeaway

This study shows that in places where certain bacteria are common, they can mix and change a lot, making new versions that might be better at making people sick.