Bovis ISSN 2398-2993

Streptococcus zooepidemicus

Contributor(s): Veronica Fowler , Tammy Hassel




  • Kingdom: bacteria.
  • Phylum: Firmicutes.
  • Class: Bacilli.
  • Order: Lactobacillales.
  • Family: Streptococcaceae.
  • Genus: Streptococcus.
  • Species: Streptococcus zooepidemicus.
  • Phylogenetically, Streptococcus equi ssp. zooepidemicus (SEZ) is regarded as the ancestral species of the closely related clonal subspecies Streptococcus equi spp. equi (SEE).


  • Streptococcus grow in chains or pairs.
  • The name comes from the Greek word Streptós  - “twisted, pliant”, (like a chain) and is couple with the modern Latin coccus - spherical bacterium, derived from the Greek word for berry, 'Kokkos'.

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Clinical Effects



  • Found as a commensal or opportunistic pathogen on mucous membranes in many animal hosts including cattle.


  • Cells divide by binary fission to produce pairs or chains.


  • Indirect transmission by contaminated environment (eg fomites, nasal discharge or exudates).
  • Horses have been implicated in transmitting disease by direct contact to cattle in multiple publications.

Pathological effects


Control via animal

  • Isolate and treat clinically affected animals.
  • Isolate and treat exposed animals (to control outbreak).
  • Quarantine until 2 weeks after resolution of signs.

Control via chemotherapies

  • Usually susceptible to penicillins Penicillin, cephalosporins, potentiated sulfas, macrolides, chloramphenicol.
  • Often resistant to aminoglycosides and tetracyclines Oxytetracycline Chlortetracycline.
  • Treatment only effective if started early following onset of clinical signs.

Control via environment

  • Clean, disinfect and dry all environmental surfaces that were exposed to infected cattle.
  • Most disinfectants, at recommended use dilutions and contact times, effectively kill pathogenic Streptococci.
  • Use of separate protective clothing (glove, mask, footwear, etc) when examining infected animals.


  • Research groups are actively evaluating a range of possible vaccines.


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Further Reading


Refereed Papers

  • Recent references from PubMed and VetMedResource.
  • Båverud V, Johansson B K, Aspan A (2007) Real-time PCR for detection and differentiation of Streptococcus equi subsp. equi and Streptococcus equi subsp. zooepidemicus. Veterinary Microbiology 124 (3–4), 219-229 PubMed.
  • Bordes-Benítez A, Sánchez-Oñoro M, Suárez-Bordón P, García-Rojas A-J, Saéz-Nieto J-A, González-García A, Alamo-Antúnez I, Sánchez-Maroto A & Bolaños-Rivero M (2006) Outbreak of Streptococcus equi subsp. zooepidemicus infections on the island of Gran Canaria associated with the consumption of inadequately pasteurized cheese. Eur J Clin Microbiol Infect Dis 25, 242–246 PubMed.
  • D M Bezek (1998) Genus identification and antibiotic susceptibility patterns of bacterial isolates from cows with acute mastitis in a practice population. J Am Vet Med Assoc 212, 404–406 PubMed.
  • Sharp M W et al (1995) S Zooepidemicus Infection and Bovine Mastitis. Vet Rec 137 (5), 128 PubMed.
  • Edwards A, Roulson M & Ironside M J (1988) A milk-borne outbreak of serious infection due to Streptococcus zooepidemicus (Lancefield group C). Epidemiol Infect 101, 43–51 PubMed.