Equis ISSN 2398-2977

Klebsiella pneumoniae

Contributor(s): Sarah Binns, Susan Dawson, Richard Walker, Jamie Prutton




  • Family: Enterobacteriaceae.
  • GenusKlebsiella.
  • Speciespneumoniae.


  • Klebsiella: named after T.A.E. Klebs (1834-1913) - German bacteriologist.
  • Pneumoniae: Gk: pneuma - wind, breath.

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Clinical Effects



  • Widespread in environment.
  • Colonizes mucous membranes, especially of gastrointestinal and genital tracts. May be cultured from semen.


  • Direct or indirect contact.
  • Many infections endogenous.
  • Venereal transmission may occur.

Pathological effects

  • Opportunistic infections develop at immunocompromised sites.
  • K. pneumonia is a common cause of nosocomial infections.
  • Has been associated with pneumonia, placentitis, metritis Uterus: endometritis - bacterial, peritonitis Abdomen: peritonitis and cholangiohepatitis in horses.
  • Endotoxin (lipopolysaccharide) consists of polysaccharide antigens and Lipid A, the toxic moiety → internalized by host cells → stimulates secretion of inflammatory mediators → endotoxemia.
  • Some strains produce exotoxins.
  • Pneumonia has a survival rate of 70%, evidence of hemorrhagic nasal discharge was associated with non-survival. Most cases will present SIRS associated symptoms, pyrexia and hemoptysis.

Other Host Effects

  • May colonize mucous membranes of healthy individuals, particularly in gastrointestinal and genital tracts.


Control via animal

  • Hygiene, especially during mating.
  • Uterine swabs and semen samples to detect infected animals.

Control via chemotherapies

  • Antibiotic susceptibility testing should be carried out; transferable resistance (carried by R. plasmids) is common, eg to gentamicin Gentamicin.
  • Uniformly resistant to ampicillin Penicillin G.

Control via environment

  • Hygiene, especially removal of soiled bedding.
  • Susceptible to common disinfectants.


  • None available.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Estell K E, Young A, Kozikowski T, Swain E A et al (2016) Pneumonia caused by Klebsiella spp in 46 horses. J Vet Int Med 30 (1), 314-321 PubMed.
  • Hong C B, Donahue J M, Giles R C et al (1993) Etiology and pathology of equine placentitis. J Vet Diagn Invest (1), 56-63 PubMed.
  • Ensink J M, Vanklingeren B, Houwers D J et al (1993) In vitro susceptibility to antimicrobial drugs of bacterial isolates from horses in the Netherlands. Equine Vet J 25 (4), 309-313 PubMed.

Other sources of information

  • Horserace Betting Levy Board (2016) Codes of Practice. 5th Floor, 21 Bloomsbury Street, London WC1B 3HF, UK. Tel: +44 (0)207 333 0043; Fax: +44 (0)207 333 0041; Email: enquiries@hblb.org.uk; Website: http://codes.hblb.org.uk.