970 bytes added ,  12:05, 29 December 2008
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*Cause suppurative infections in many different animals
 
*Cause suppurative infections in many different animals
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*Cause abscess formation and septicaemia
 
*Cause mastitis, metritis, polyarthritis, meningitis
 
*Cause mastitis, metritis, polyarthritis, meningitis
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*Often commensals on mucous membranes of upper respiratory and lower urogenital tract
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*Opportunistic infections
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*Catalase negative, facultative anaerobes
 
*Catalase negative, facultative anaerobes
 
*Fastitidious - require enriched media such as blood or serum
 
*Fastitidious - require enriched media such as blood or serum
*Small haemolytic, translucent colonies
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*Small haemolytic, translucent colonies, some mucoid
 
*Catalase negative
 
*Catalase negative
 
*Susceptible to desiccation
 
*Susceptible to desiccation
*Commensals on mucous membranes of upper respiratory and lower urogenital tract
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===Pathogenicity===
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===Pathogensis and Pathogenicity===
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*Beta-haemolytic strains more pathogenic than alpha-haemolytic strains
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*Virulence factors include streptolysins, hyaluronidase, DNase, streptokinase and proteases
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*''S. pyogenes, S. pneumoniae'' and some strains of ''S. equi'' have polysaccharide capsules which are antiphagocytic
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*''S. pyogenes'' and ''S. equi'' have antiphagocytic cell wall M proteins
       
===Clinical infections===
 
===Clinical infections===
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*Primary or secondary infections following viral infection
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*Neonatal septicaemia related to maternal genital tract infection
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*Strangles
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**Highly infectious disease of horses caused by ''Streptococcus equi'' subsp. ''equi''
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**Upper respiratory tract disease with fever and abscessation of regional lymph nodes
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**Outbreaks in groups of young horses
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**
       
===Diagnosis===
 
===Diagnosis===
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*Swabs of pus or exudate cultured on blood agar and MacConkey agar
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*No growth on MacConkey except ''S. faecalis''
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*PCR, Lancefield grouping and biochemical tests
     
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