Do streptococci swap between dogs and children?

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Wednesday, 12 June, 2013

A paper by the Indigenous scientist, Layla Schreiber, and her colleagues (including THS Director Rick Speare) has helped answer this important question. The paper describes a case where a species of bacteria, Streptococcus dysgalactiae subsp. equisimilis (SDSE), was isolated independently from a dog and a child in the same household (Schreiber et al 2013).

The strain was identified using the API 20Strep system, 16S rRNA gene sequencing, emm sequence typing (emmST) and multilocus sequence typing (MLST) as a group C SDSE. Although the isolate did not cause disease in either dog or child, this finding provides proof that cross-species transmission does occur. Group C SDSE has been associated with streptococcal disease in humans.

In particular it is becoming apparent that Group A streptococcal virulence genes (found on S. pyogenes carried by humans) jump across to other streptococci carried by dogs, making these strains potentially pathogenic to humans (Boon 2007). The role of dogs in the epidemiology of group C streptococci in humans in rural and remote Indigenous communities needs clarfication.

Reference

Boon V. Factors responsible for the high rate of kidney disease in Indigenous Australians: a multifaceted approach focusing on streptococcal disease. PhD thesis, James Cook University. 2007.

Schrieber L, Towers R, Muscatello G, Speare R. Transmission of Streptococcus dysgalactiae subsp. equisimilis between Child and Dog in an Aboriginal Australian Community. Zoonoses and Public Health 2013 (e-pub on line) doi: 10.1111/zph.12057

Please contact Rick Speare (rickspeare@gmail.com} for a personal copy of Layla's paper for scientific use.

Posted by Rick Speare