Category:Mycoplasmas
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Overview
- Pathogens belong to the Mycoplasma and Ureaplasma genera
- Cause many diseases especially respiratory diseases of farm animals including contagious bovine pleuropneumonia
- Can be involved in mastitis and conjunctivitis in cattle
- Implicated in respiratory and urinary tract diseases in dogs and cats
- Non-pathogenic mycoplasmas present in the rumen
- Live on mucous membranes of oronasal cavity, conjunctiva and intestines
- Stress factors and concurrent disease may predispose to tissue invasion
- Usually host-specific
- Limited survival in the environment
Characteristics
- Smallest free-living prokaryotic organism
- Pleomorphic organisms
- Have no peptidoglycan cell wall
- Susceptible to dessication, heat and disinfectants
- Require enriched media containing animal protein, sterol and a source of DNA for growth
- Colonies have a fried egg appearance
- Most are facultative anaerobes
Pathogenesis and pathogenicity
- Mycoplasmas adhere to host cells and produce toxins
- Some adhere to neutrophils and macrophages and prevent phagocytosis
- Mycoplasmas induce proliferation of macrophages and [[monocytes]], and release of cytokines such as TNF and interleukins
- Cause damage to cilia in the respiratory tract leading to pneumonia
- Molecular mimicry allows some mycoplasmas to avoid the host immune response and may initiate immune-mediated disease
Diagnosis
- Samples can be tested for the presence of mycoplasmas by fluorescent antibody techniques, peroxidase techniques and PCR
- Biochemical profiles such as urease production can be used for identification
- Ureaplasmas produce urease, whereas Mycoplasmas do not metabolise urea
- Serolgy is required for specific identification including complement fixation tests, ELISA, agglutination tests and haemagglutination-inhibition tests
- Growth inhibition tests using specific antisera can be used as well as fluorescent antibody tests
Mycoplasma mycoides subsp. mycoides
Mycoplasma bovis
Mycoplasma capricolum subsp. capricolum
Mycoplasma mycoides subsp. mycoides
Mycoplasmas of poultry
- M. gallisepticum
- Causes chronic repsiratory disease in chickens and infectious sinusitis in turkeys
- Transmission via the egg and aerosol
- Reduced egg production
- Identification by serum plate agglutination test, haemagglutination inhibition and ELISA
- Controlled in specific-pathogen-free flocks
- Modified live vaccines and bacterins available
- M. meleagridis
- Hatching problems; airsacculitis in young poults; joint and bone deformities in growers; poor growth rates
- Transmitted mainly via eggs and semen
- Serum plate agglutination test for identification
- In-water tylosin for first 10 days of life
- Eggs can be dipped in tylosin
- M synoviae
- Causes infectious synovitis in chickens and turkeys
- Transmitted by aerosol
- Synovitis, arthritis, respiratory disease
- Confirmation by isolation or serology
- In-feed tetracycline
- Eradication through specific-pathogen-free flocks
Other mycoplasmas
- M. bovis, M. dispar and Ureaplasma can be involved in Enzootic pneumonia of calves
- M. ovipneumoniae is implicated in enzootic pneumonia of lambs
- M. felis may be involved in mild respiratory infection
- Mycoplasmas may cause lymphocytic chronic inflammation (peribronchiolar and perialveolar cuffing)
- Cause peritonitis in sheep, peritonitis in goats and peritonitis in pigs
Pages in category "Mycoplasmas"
The following 14 pages are in this category, out of 14 total.