Streptococcal toxic shock syndrome in dogs

Area of Science:

• Veterinary Medicine
• Infectious Diseases
• Microbiology

Background:

• Severe invasive infections in dogs are uncommon but can be life-threatening.
• Group G streptococci (GGS) are known pathogens in humans, but their role in severe canine infections is less understood.

Purpose of the Study:

• To investigate the clinical, pathological, and bacteriological features of severe invasive infections caused by GGS in dogs.
• To characterize the GGS isolates from infected dogs, including their virulence factors.

Main Methods:

• A prospective case series involving 7 dogs with severe streptococcal infections in southern Ontario over 6 months.
• Molecular typing of GGS isolates using pulsed-field gel electrophoresis.
• Detection of specific virulence genes (emm1.0, speA, speB, speF, hasA, hasB, scpA) via DNA probes or PCR.

Main Results:

• Three dogs with streptococcal shock without necrotizing fasciitis died within 48 hours; four dogs with shock and necrotizing fasciitis survived with aggressive treatment.
• Five of six GGS isolates were identified as Streptococcus canis; one showed characteristics of human GGS strains.
• Molecular typing revealed unrelated isolates, and most canine isolates lacked virulence genes common in human GGS toxic shock infections, except for the emm1.0 gene in one isolate.

Conclusions:

• The emergence of severe invasive GGS infections in dogs suggests the development of a virulent GGS strain in southern Ontario.
• Canine GGS isolates appear genetically distinct from human strains and possess limited virulence factors associated with human GGS toxic shock.