Lapis ISSN 2398-2969

Streptococcus spp

Contributor(s): Susan Dawson, Livia Benato




  • Family: Streptococceae.
  • Genus:Streptococcus.
  • Streptococcusspp are Gram-positive cocci, non-motile aerobes or facultative anaerobes, oxidase and catalase-negative. They are the cause of local and systemic pyogenic infections in animals and people. However, someStreptococcusspp can be non-pathogenic and found in the normal microflora of humans and animals.
  • S. canishas been found in dogs and a variety of other animals, including rabbits.
  • S. agalactiaehas been recently reported in domestic rabbits.
  • S. suishas been reported in wild rabbits, but not considered a risk for humans and pigs.


  • Greek:streptos- twisted.
  • Latin:coccus- spherical.

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Clinical Effects



  • Many commensals on mucosal surfaces of respiratory and urogenital systems.


  • Streptococci are resident on the mucous membranes of the upper respiratory tract, lower genital, and alimentary tract.
  • Reproduction is by binary fission to form chains or pairs.


  • Streptococci are transmitted by inhalation, ingestion, or sexual contact. Congenital and indirect (via fomites) transmission also occur.

Pathological effects

  • Capsules of some species antiphagocytic.
  • Pyogenic bacteria.
  • Beta-hemolytic isolates most pathogenic.
  • Exotoxins produced - streptolysin O and S, hyaluronidase, DNase, protease and streptoleinase.
  • Incubation: varies with the different form ofStreptococcusspp and diseases.

Other Host Effects

  • In 2011,S. agalactiaecaused 42% mortality in a rabbit colony (China). The main clinical signs included acute respiratory distress syndrome, fever, paddling and convulsions.


Control via animal

  • Animals suspected of streptococcosis should be separated from healthy animals.

Control via chemotherapies

  • Pathogenic streptococci are usually susceptible to penicillin   Penicillin  , erythromycin, chloramphenicol   Chloramphenicol  , cefalexin   Cefalexin  and other cephalosporins, and potentiated sulfonamides   Trimethoprim / sulfadiazine  . Also, amoxicillin   Amoxicillin  , ampicillin, clindamycin, chloramphenicol   Chloramphenicol  and enrofloxacin   Enrofloxacin  can be used to treat streptococcosis in animals.
  • Streptococci are often resistant to aminoglycosides and tetracycline   Oxytetracycline  .
  • In a study on rabbit mandibular and maxillary abscesses,S. millerigroup bacteria were isolated amongst others. These bacteria were found to be susceptible to clindamycin, penicillin and ceftriaxone and ciprofloxacin. Only 7% were susceptible to trimethoprim-sulfamethoxazole.
  • Another study showedS. agalactiae to be sensitive to florfenicol, ampicillin, gentamicin and norfloxacin, as well as being resistant to penicillin, amoxicillin and tetracycline.

Control via environment

  • Good hygiene and cleaning.
  • Disinfectants and detergents such as 1% sodium hypochlorite, 70% ethanol, formaldehyde, glutaraldehyde and iodine-based disinfectants can kill streptococci.
  • Also, streptococci are not resistant to moist or dry heat >121°C.


  • No commercial vaccines are available.

Other countermeasures

  • Prevention: good husbandry and diet and a stress-free environment can reduce the risk of streptococcosis.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Ren S Y, Geng Y, Wang K Y et al (2014) Streptococcus agalactiae infection in domestic rabbits, Oryctolagus cuniculusTransbound Emerg Dis 61 (6), e92-95 PubMed.
  • Sánchez del Rey V, Fernández-Garayzábal J F, Briones V et al (2013) Genetic analysis of Streptococcus suis isolates from wild rabbits. Vet Microbiol 165 (3-4), 483-486 PubMed.
  • Engin B & Karagul Yuceer Y (2012) Effects of ultraviolet light and ultrasound on microbial quality and aroma-active components of milk. J Sci Food & Agri 92 (6), 1245-1252 PubMed.
  • Tyrrell K L, Citron D M, Jenkins J R et al (2002) Periodontal bacteria in rabbit mandibular and maxillary abscesses. J Clin Microbiol 40 (3), 1044-1047 PubMed.

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