Difference between revisions of "Category:Mycobacterium species"

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|pagetitle =Mycobacterium species
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|pagebody = *Mycobacteruim organisms belong to the family Mycobacteriaceae, order Actinomycetales. This class of organism includes obligate pathogens, opportunistic pathogens and saprophytes; they can cause chronic, progressive, granulomatous infections including tuberculosis, [[Johne's Disease|Johne's disease]] and feline leprosy. ''M. bovis'', ''M. tuberculosis'' and ''M. avium'' cause [[Respiratory Bacterial Infections - Pathology#Tuberculosis|tuberculosis of cattle]], [[Respiratory Bacterial Infections - Pathology#Tuberculosis in pigs|tuberculosis of pigs]] and [[Respiratory Bacterial Infections - Pathology#Tuberculosis in dogs|tuberculosis of dogs]] respectively. ''Mycobacterium leprae'' and ''M.lepraemurium'' cause human, feline/murine leprosy respectively. Localized opportunistic [[Bacterial skin infections - Pathology#Bacterial granulomatous dermatitis|skin]] and subcutaneous infection can be caused by saprophytic and rapidly growing atypical mycobacteria.
  
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===Overview===
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Environmental species are found in soil, vegetation and water. Mycobacterium organisms are
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non-motile, non-spore forming weakly Gram-positive acid-fast rods. They require egg-based media for growth, forming slow-growing (three weeks are required for culture) colonies that stain with carbol dyes and resist subsequent decolorization with inorganic acids; this characteristic which is due to the spatial arrangement of mycolic acids within the cell wall makes them acid fast. They are identified by Ziehl-Neelson staining and differentiated by culture, biochemical tests, chromatography and molecular techniques.
  
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*Mycobacterial infections are caused by bacteria belonging to the family Mycobacteriaceae, order Actinomycetales
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Mycobacterium species are resistant to disinfectants and environmental conditions, but are  susceptible to pasteurisation.
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*Includes obligate pathogens, opportunistic pathogens and saprophytes
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|contenttitle =Content
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*Cause chronic, progressive, granulomatous infections
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|contentbody =<big><b>
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*Cause tuberculosis, [[Intestines Proliferative Enteritis - Pathology#Paratuberculosis (Johnes disease)|Johne's disease]] and feline leprosy
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<categorytree mode=pages>Mycobacterium species</categorytree>
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*''M. bovis'', ''M. tuberculosis'' and ''M. avium'' cause [[Respiratory Bacterial Infections - Pathology#Tuberculosis|tuberculosis of cattle]], [[Respiratory Bacterial Infections - Pathology#Tuberculosis in pigs|tuberculosis of pigs]] and [[Respiratory Bacterial Infections - Pathology#Tuberculosis in dogs|tuberculosis of dogs]] respectively
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</b></big>
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*The 'classical' tuberculosis lesions are caused by the [[Mycobacterium tuberculosis complex]]
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|logo =bugs-logo copy.png
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*The Johne's type lesions are caused by the [[Mycobacterium avium complex]]
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}}
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*Environmental species are found in soil, vegetation and water
 
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*''Mycobacterium leprae'' and ''M.lepraemurium'' cause human, feline/murine leprosy respectively
 
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*Atypical mycobacteriosis is a localized opportunistic skin and subcutaneous infection caused by saprophytic and rapidly growing atypical mycobacteria
 
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*Granulomatous lesions in [[Muscles Inflammatory - Pathology#Tuberculosis|muscle]] and [[Bacterial skin infections - Pathology#Bacterial granulomatous dermatitis|skin]]
 
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*Skin tuberculosis of cattle causes nodules along the lymphatics of the limbs
 
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*Bovine farcy is thought to be caused by ''M. senegalense'' and ''M. farcinogenes''
 
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*Saprophytic mycobacteria cause granulomatous lesions
 
  
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===Characteristics===
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[[Category:Bacterial Organisms]]
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[[Category:Gram_positive_bacteria]]
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*Aerobic, weakly Gram-positive acid-fast rods
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[[Category:Rods]]
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*Non-motile, non-spore forming
 
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*Cell walls contain mycolic acid
 
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*Require egg-based media for growth
 
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*Slow-growing colonies
 
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*Resistant to disinfectants and environmental conditions; susceptible to pasteurisation
 
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*Mycobacteria stain with carbol dyes and resist subsequent decolorization with inorganic acids; this characteristic which is due to the spatial arrangement of mycolic acids within the cell wall makes them acid fast
 
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===Identification===
 
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*Identified by Ziehl-Neelson staining
 
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*Differentiated by culture, biochemical tests, chromatography and molecular techniques
 
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*Pathogenic species require at least three weeks for growth on egg-based media
 
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[[Mycobacterium bovis]]
 
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[[Mycobacterium avium]]
 
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===Feline leprosy===
 
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*Caused by ''M. lepraemurium''
 
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*Sporadic infections of cats via bites from infected rodents
 
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*Subcutaneous nodules form usually on the head or limbs and can ulcerate
 
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*Smears reveal Ziehl-Neelson-positive rods
 
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*Diagnosis by histopathology
 
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*Treatment includes excision of lesions
 
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===[[Intestines Proliferative Enteritis - Pathology#Paratuberculosis (Johnes disease)|Johne's Disease (paratuberculosis)]]===
 
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*[[Intestines Proliferative Enteritis - Pathology#Paratuberculosis (Johnes disease)|Johne's Disease]] is a chronic, contagious enteritis of ruminants
 
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*Caused by ''M avium'' subsp. ''paratuberculosis''
 
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*Epidemiology
 
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**Transmitted to young calves by ingestion of mycobacteria in faeces of infected adults
 
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**Organisms viable in environment for long periods
 
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**Long incubation period with clinical signs appearing in cattle over 2 years of age
 
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**Subclinical carriers can occur, shedding organisms in their faeces
 
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*Pathogenesis and pathogenicity
 
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**''M avium'' subsp. ''paratuberculosis'' is an intracellular pathogen
 
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**Mycobacteria are ingested by macrophages in the Peyer's patches
 
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**Survival and replication of mycobacteria in macrophages initiate an immune-mediated granulomatous reaction
 
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**Lymphocytes and macrophages accumulate  in the lamina propria and submucosa, resulting in marked thickening and folding of the intestinal wall
 
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**Mesenteric lymph nodes are enlarged
 
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**A protein-losing enteropathy results, along with failure to absorb nutrients and water
 
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*Clinical signs
 
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**Diarrhoea, initially intermittent, and weight loss in cattle
 
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**Weight loss in sheep and goats
 
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**Rapidly fatal with weight loss and diarrhoea in some deer
 
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*Diagnosis
 
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**All diagnostic procedures have faults but include:
 
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**Microscopy of rectal biopsies
 
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**Faecal culture
 
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**Serology of serum including complement fixation tests, agar-gel immunodiffusion test and an ELISA
 
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**Histopathology of intestines and lymph nodes
 
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**Isolation and identification of mycobacteria from faeces and tissues
 
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**Ziehl-Neelson-positive smears
 
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**Intradermal tuberculin test
 
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**DNA probes for detection in faeces
 
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*Control
 
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**Slaughter of affected animals
 
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**Detection and slaughter of subclinical shedders using faecal culture, DNA probes and ELISA
 
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**Good hygiene to protect young calves
 
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**Separation and isolation of calves from affected dams
 
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**Inactivated adjuvanted vaccines are available and reduce shedding of mycobacteria but do not eliminate infection
 
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[[Category:Bacteria]][[Category:Gram_positive_bacteria]][[Category:Rods]]
 

Latest revision as of 18:55, 1 November 2010

Mycobacterium species

*Mycobacteruim organisms belong to the family Mycobacteriaceae, order Actinomycetales. This class of organism includes obligate pathogens, opportunistic pathogens and saprophytes; they can cause chronic, progressive, granulomatous infections including tuberculosis, Johne's disease and feline leprosy. M. bovis, M. tuberculosis and M. avium cause tuberculosis of cattle, tuberculosis of pigs and tuberculosis of dogs respectively. Mycobacterium leprae and M.lepraemurium cause human, feline/murine leprosy respectively. Localized opportunistic skin and subcutaneous infection can be caused by saprophytic and rapidly growing atypical mycobacteria.

Environmental species are found in soil, vegetation and water. Mycobacterium organisms are non-motile, non-spore forming weakly Gram-positive acid-fast rods. They require egg-based media for growth, forming slow-growing (three weeks are required for culture) colonies that stain with carbol dyes and resist subsequent decolorization with inorganic acids; this characteristic which is due to the spatial arrangement of mycolic acids within the cell wall makes them acid fast. They are identified by Ziehl-Neelson staining and differentiated by culture, biochemical tests, chromatography and molecular techniques.

Mycobacterium species are resistant to disinfectants and environmental conditions, but are susceptible to pasteurisation.

Content

▼ Mycobacterium species
  Johne's Disease
  Mycobacterium avium
  Mycobacterium bovis
  Mycobacterium lepraemurium

Pages in category "Mycobacterium species"

The following 4 pages are in this category, out of 4 total.

J

M

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