Streptococcus spp

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Streptococcus spp viewed under light microscopy

Streptococcus spp are a ubiquitous bacteria of canine mucosal membranes and skin.

they are capable of causing infections in skin and when internalized, can cause systemic multiorgan pathology either alone or in combination with other bacteria and viruses.

Pathogenic species include:

  • Steptococcus canis - commonly associated with pyometra
  • Streptococcus equi subsp zooepidemicus - associated with rhinitis and hemorrhagic pneumonia[1]
  • Streptococcus pyogenes - purulent-producing bacteria
  • Streptococcus β-haemolyticus - reproductive tract[2]
  • Streptococcus constellatus - pyoderma[3]
  • Streptococcus suis - isolated from pig-ear treats[4]

Most Streptococcus spp are non-pathogenic, but a few species can cause significant morbidity and mortality ranging from death in young dogs, to pyometra and respiratory disease such as pneumonia.

These bacteria have a propensity for colonizing the reproductive tract and can be found in the vaginal tract in prepartum mammary secretions and postpartum milk[5].

Diagnosis is based on culture and sensitivity in the laboratory.

Streptococcus spp quickly develop antimicrobial resistance to many antibiotics including doxycycline but are usually sensitive to amoxycillin/clavulanate and fluorquinolone-based drugs such as enrofloxacin[6].


  1. Chalker VJ et al (2012) Genetic diversity of Streptococcus equi subsp. zooepidemicus and doxycycline resistance in kennelled dogs. J Clin Microbiol 50(6):2134-2136
  2. Groppetti D et al (2012) Vaginal bacterial flora and cytology in proestrous bitches: role on fertility. Theriogenology 77(8):1549-1556
  3. De Martino L et al (2012) Streptococcus constellatus-associated pyoderma in a dog. J Med Microbiol 61(3):438-442
  4. Muckle A et al (2010) Isolation of Streptococcus suis from the urine of a clinically ill dog. Can Vet J 51(7):773-774
  5. Milani C et al (2012) Antimicrobial resistance in bacteria from breeding dogs housed in kennels with differing neonatal mortality and use of antibiotics. Theriogenology 78(6):1321-1328
  6. Silley P et al (2012) Bactericidal properties of pradofloxacin against veterinary pathogens. Vet Microbiol 157(1-2):106-111