Difference between revisions of "Mycoplasmas species - Overview"
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− | == | + | ===Overview=== |
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− | + | *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|neutrophils]] and macrophages and prevent phagocytosis | ||
+ | *Mycoplasmas induce proliferation of macrophages and [[[[Monocytes|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=== | |
− | [[Category: | + | *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 | ||
+ | |||
+ | ===Other mycoplasmas=== | ||
+ | |||
+ | *''M. bovis'', ''M. dispar'' and ''Ureaplasma'' can be involved in [[Respiratory Bacterial Infections - Pathology#Enzootic pneumonia of calves|Enzootic pneumonia of calves]] | ||
+ | *''M. ovipneumoniae'' is implicated in [[Respiratory Bacterial Infections - Pathology#Enzootic pneumonia of lambs|enzootic pneumonia of lambs]] | ||
+ | *''M. felis'' may be involved in mild [[Respiratory Bacterial Infections - Pathology#Mycoplasma felis|respiratory infection]] | ||
+ | *Mycoplasmas may cause [[Chronic Inflammation - Pathology#Lymphocytic Inflammation|lymphocytic chronic inflammation]] (peribronchiolar and perialveolar cuffing) | ||
+ | *Cause [[Peritonitis#In sheep|peritonitis in sheep]], [[Peritonitis#In goats|peritonitis in goats]] and [[Peritonitis#In pigs|peritonitis in pigs]] | ||
+ | |||
+ | ==cattle== | ||
+ | |||
+ | **[[:Category:Mycoplasmas|'''''Mycoplasma spp.''''']] | ||
+ | ***May be respinsible for some chronic cases but difficult to prove as hard to isolate | ||
+ | ***Fibrinous polyarthritis |
Revision as of 11:24, 31 July 2010
This article is still under construction. |
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
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
cattle
- Mycoplasma spp.
- May be respinsible for some chronic cases but difficult to prove as hard to isolate
- Fibrinous polyarthritis
- Mycoplasma spp.