Mycoplasma are the smallest prokaryotes which belong to the class Mollicutes. They are extracellular parasites, although they may colonize human and animal hosts without being pathogenic.5 These bacteria lack cell walls and, therefore, are resistant to penicillins, but are susceptible to other antimicrobials. Mycoplasmas cause several important diseases in cattle, chickens, and swine.2

Mycoplasmas colonize the mucous membranes of the respiratory and genital tracts as well as red blood cells of many animal and human species. In dogs, they are considered to be part of the normal bacterial flora of the upper respiratory tract. Mycoplasma canis, Mycoplasma cynos, Mycoplasma edwardii, Mycoplasma maculosum, and Mycoplasma spumans have been isolated from the nasal cavity of healthy and diseased dogs. However, M. cynos is the only species that has commonly been associated with respiratory diseases whicn frequently become chronic.1

Various Mycoplasma species have also been recovered from dogs with pneumonia. There are, however, conflicting reports on the presence of mycoplasmas in the lower respiratory tract of healthy dogs. It is also assumed that mycoplasmas colonize the lungs during pneumonia, or due to the immunosuppressive effects of canine distemper virus or other viral agents. Mycoplasma felis is occasionally isolated from horses with severe pleuritis and lower respiratory tract diseases.4

In chickens Mycoplasma gallisepticum (MG) infection is principally a respiratory disease. With tracheal infections, there may be rattling sounds, nasal discharge, and coughing. There are documented cases of zoonotic infections in humans. M. felis has produced septic arthritis of the hip and knee in a person who was receiving glucocorticoid therapy.3

Mycoplasma genitalium is a facultative anaerobic organism with increasing drug resistance and a recognized cause of nongonococcal urethritis in men. In women, M. genitalium has been associated with cervicitis, endometritis, pelvic inflammatory disease (PID), infertility, susceptibility to human immunodeficiency virus (HIV), and adverse birth outcomes.7


  1. Simultaneous Canine Distemper Virus, Canine Adenovirus Type 2, and Mycoplasma Cynos Infection in a Dog with Pneumonia (
  2. Microbiology. Lansing M. Prescott, John P.Harley, Donald A. Klein
  3. Greene Infectious Diseases of the Dog and Cat, Fourth Edition
  4. Shmuel Razin, Richard Herrmann. Molecular Biology and Pathogenicity of Mycoplasmas
  5. O. M. Radostits, J. H. Arundel. Veterinary Medicine
  6. Mycoplasma gallisepticum Infection in Poultry (
  7. Mycoplasma genitalium: An Overlooked Sexually Transmitted Pathogen in Women? Samsiya Ona, 1 , * Rose L. Molina, 2 , 3 and Khady Diouf 1 Infect Dis Obstet Gynecolv.2016



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