Penis: bacterial colonization

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  • Bacteria are commonly isolated from the penis; harmless commensals must be differentiated from agents of venereal disease.
  • Cause : significant organisms are Klebsiella pneumoniae , Pseudomonas aeruginosa and Taylorella equigenitalis .
  • Signs : subclinical infection or colonization on external genitalia of stallions. Most commonly, stallion is lesionless carrier. Rarely, a stallion may have internal accessory sex gland infection with Pseudomonas resulting in purulent material being present in ejaculates.
  • Diagnosis : microbiologic culture of swabs from appropriate sites .
  • Treatment : removal of smegma; administration of antimicrobials if necessary.
  • Prognosis : good with appropriate therapy.


Differential diagnosis

  • Commensal organisms.


Clinical signs

  • No clinical signs.
  • Semen: hemosemenFig.1 Semen: hemosemen
    Hemospermia   (Fig. 1)  .



  • Good with appropriate therapy in CEM.
  • Good to fair in Pseudomonas and Klebsiella infections.
  • Chronic carriers can occur.

Expected response to treatment

  • Negative bacteriologic cultures for pathogens.

Reasons for treatment failure

  • Overzealous antiseptic washing - removing normal flora.
  • Failure to eliminate infection by inappropriate or inadequate therapy.
  • Failure to implement Codes of Practice rigorously.
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