Difference between revisions of "Actinobacillus suis"

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Also known as: '''''A. suis'''''
 
 
{{Taxobox
 
{{Taxobox
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|name              =''Actinobacillus suis''
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|name              =
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|kingdom            = [[:Category:Bacteria|Bacteria]]
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|kingdom            =
 
|sub-kingdom        =
 
|sub-kingdom        =
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|phylum            = Proteobacteria
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|phylum            = Bacteria
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|super-class        =  
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|super-class        =
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|class              = Zymobacteria
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|class              = Proteobacteria
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|sub-class          = Alphaproteobacteria
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|sub-class          = Zymobacteria
 
|super-order        =
 
|super-order        =
 
|order              = Pasteurellales
 
|order              = Pasteurellales
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|family            = Pasteurellaceae
 
|family            = Pasteurellaceae
 
|sub-family        =
 
|sub-family        =
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|genus              = [[Actinobacillus species|Actinobacillus]]
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|genus              = Actinobacillus
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|species            = ''Actinobacillus suis''
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|species            = Actinobacillus suis
 
}}
 
}}
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==Introduction==
 
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[[File:Actinobacillus suis.jpg|thumb|200px|right| ''Actinobacillus suis'' Gram stain]]
 
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''A.suis'' is a beta-haemolytic '''Gram-negative bacterium'''. It has many strains due to differences in their '''lipopolysaccharides (LPS)''', which are known as ''''O' antigens''' and are referred to as '''O1,O2''' and '''O3''' and '''capsules (CPS)''', refered to as '''K antigen''' with variants described as '''K1, K2''' and '''K3'''. More than 95% of ''A. suis'' clinical isolates are cross-reactive with O1/K1 or O2/K3 antiserum and more severe infection were noted with O2/K2 strain <ref name="Slavic et al., 2000">Slavic, D., DeLay, J., Hayes, M.A., MacInnes, J.I. (2000) '''Comparative pathogenicity of different ''Actinobacillus suis'' O/K serotypes'''. ''Canadian Journal of Veterinary Research'', 64(2):81-87</ref>. This '''opportunistic''' bacteria mainly causes [[Actinobacillosis - Pig|'''actinobacillosis in pigs''']], but has also been linked to diseases in neonatal calves, waterfowl, alpacas, horses and [[Actinobacillus suis#Signalment|various other species]].
 
  
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Other haemolytic strains of ''Actinobacillus'' species have been linked to various diseases in horses such as [[Actinobacillus equuli| ''Actinobacillus equuli'']] and [[Actinobacillosis - Cattle|''Actinobacillus ligneresii'']]. The latter species also causes [[Actinobacillosis - Cattle|wooden tongue in cattle]].
 
  
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''A. suis''-like organism may cause acute haemorhagic pulmonary infarction and necrotizing pneumonia as well as septicaemia in horses.
 
  
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''A. suis'' are able to resist bile and serum and have genes that encode toxins similar to apxI and apxII of [[Actinobacillus pleuropneumoniae|''A. pleuropneumoniae'']], but they are less virulent.  Once an animal is infected with ''A. suis'' it can provide '''partial cross protection against ''A. pleuropneumoniae'''''.
 
  
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==Signalment==
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*May be present in upper respiratory tract of sows
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''A.suis'' can infect all ages of pigs and it is thought that incidence of the disease is increasing, especially in North American high-health-status herds.
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*Pathogenicity and clinical signs:
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**Infection of piglets via aerosol or possibly skin abrasions
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**Fatal septicaemia in piglets 1-8 weeks old
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**Mortality up to 50% in some litters
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**Fever, respiratory distress, prostration and paddling of forelimbs seen in piglets
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**Petechial and ecchymotic haemorrhages in many organs
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**Interstitial pneumonia, pleuritis, meningoencephalitis, myocarditis and arthritis
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**Causes abscesses in joints and lungs of older pigs
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**Carried in the nasopharynx of pigs and nose of horses
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**Carriage may confer immunity to the more severe pleuropneumonia
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*Diagnosis:
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**Specimens cultured on blood agar and MacConkey agar for 1-3 days
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**Sticky haemolytic colonies
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**Pink, lactose-fermenting colonies on MacConkey agar
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*Treatment and control:
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**Bacteria usually susceptible to ampicillin, carbenicillin, potentiated sulphonamides and tetracyclines
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**Disinfect contaminated pens
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*Other animals:
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**Septicaemia and pneumonia in foals
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**Pneumonia in pigs and horses
  
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Wild hosts include anatidae (ducks, geese and swans) and [http://en.wikipedia.org/wiki/Coypu coypu] but ''A. suis'' can also affect domestic species including cattle, sheep, goats, alpacas, zebu, dogs, cats and tenuous links to equine disease have been recorded (although this is thought to be an ''A.suis''-like microorganism rather than ''A. suis'' itself). ''A. suis'' is not considered to be a zoonosis, but there is a report of a human infection after a pig bite <ref>Escande, F., Bailly, A., Bone, S., Lemozy, J. (1996) '''Actinobacillus suis infection after a pig bite'''. ''Lancet'' (British edition), 348(9031):888; 5 ref.</ref>.
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[[Category:Actinobacillus_species]][[Category:Pig Bacteria]][[Category:Respiratory Diseases - Pig]][[Category:Horse Bacteria]]
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[[Category:To_Do_-_Bacteria]][[Category:To Do - Jaimie Meagor]]
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==Clinical signs==
 
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For clinical signs in pigs see [[Actinobacillosis - Pig| '''actinobacillosis in pigs''']].  In other species, ''A. suis'' causes pneumonia like symptoms and localised infections in neonatal calf, airsaculitis in waterfowl, and polyarthritis in alpacas and acute haemorrhagic pulmonary infarction and necrotizing pneumonia in horses.
 
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==Epidemiology==
 
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The epidemiology of ''A. suis'' is poorly understood, although it can be found in the tonsils and upper respiratory tract of both healthy and diseased pigs, and isolates are genetically and biochemically similar. It is believed to be spread via '''aerosol infection''' and '''invasion of the upper respiratory tract'''. Systemic disease can be seen when infected emboli spread haematogenously throughout the body adhering to the endothelium of blood vessels or becoming trapped in smaller vessels.  It is thought to colonise piglets in the first three weeks of life but not all piglets become clinically affected and some can become carriers.
 
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==Diagnosis==
 
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''A. suis'' is difficult to culture and most of the O1 strains analysed possess '''pustulan''' (1-6,beta-D-glucan) which is a major component of fungal and lichen cell walls. Therefore, many animals have antibodies to this polysaccharide in the absence of exposure to ''A. suis''.  These antibodies may provide naive pigs with some level of protection against the O1 strains <ref name="MacInnes and Desrosiers, 1999">MacInnes, J.I., Desrosiers, R. (1999) ''' Agents of the "suis-ide diseases" of swine: ''Actinobacillus suis, Haemophilus parasuis,'' and ''Streptococcus suis'''''. ''Canadian Journal of Veterinary Research'', 63(2):83-89; 52 ref.</ref>, <ref name="Slavic et al., 2000"/>. 
 
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For more information see [[Actinobacillosis - Pig|'''actinobacillosis in pigs''']].
 
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==Distribution==
 
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Worldwide
 
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{{Learning
 
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|flashcards = [[Actinobacillus suis Flashcards| ''Actinobacillus suis'' Flashcards ]]
 
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}}
 
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== References ==
 
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<references/>
 
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{{CABI source
 
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|datasheet = [http://www.cabi.org/ahpc/Default.aspx?site=160&page=2144&LoadModule=datasheet&CompID=3&dsID=95732 Actinobacillus suis]
 
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|date = August 08, 2011
 
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}}
 
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<br><br><br>
 
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{{review}}
 
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{{OpenPages}}
 
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[[Category:Actinobacillus_species]][[Category:Pig Bacteria]][[Category:Horse Bacteria]]
 
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[[Category:CABI Expert Review]][[Category:CABI AHPC Pages]]
 

Revision as of 11:13, 20 June 2011

Phylum Bacteria
Class Proteobacteria
Sub-class Zymobacteria
Order Pasteurellales
Family Pasteurellaceae
Genus Actinobacillus
Species Actinobacillus suis



  • May be present in upper respiratory tract of sows
  • Pathogenicity and clinical signs:
    • Infection of piglets via aerosol or possibly skin abrasions
    • Fatal septicaemia in piglets 1-8 weeks old
    • Mortality up to 50% in some litters
    • Fever, respiratory distress, prostration and paddling of forelimbs seen in piglets
    • Petechial and ecchymotic haemorrhages in many organs
    • Interstitial pneumonia, pleuritis, meningoencephalitis, myocarditis and arthritis
    • Causes abscesses in joints and lungs of older pigs
    • Carried in the nasopharynx of pigs and nose of horses
    • Carriage may confer immunity to the more severe pleuropneumonia
  • Diagnosis:
    • Specimens cultured on blood agar and MacConkey agar for 1-3 days
    • Sticky haemolytic colonies
    • Pink, lactose-fermenting colonies on MacConkey agar
  • Treatment and control:
    • Bacteria usually susceptible to ampicillin, carbenicillin, potentiated sulphonamides and tetracyclines
    • Disinfect contaminated pens
  • Other animals:
    • Septicaemia and pneumonia in foals
    • Pneumonia in pigs and horses
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