Difference between revisions of "Category:Streptococcus species"

From WikiVet English
Jump to navigation Jump to search
Line 1: Line 1:
{{review}}
+
{{frontpage
 +
|pagetitle =Streptococcus species
 +
|pagebody =
 +
|contenttitle =Content
 +
|contentbody =<big><b>
 +
<categorytree mode=pages>Streptococcus species</categorytree>
 +
</b></big>
 +
|logo =
 +
}}
  
 
===Overview===
 
===Overview===
Line 49: Line 57:
  
  
<big>'''''<ncl style=bullet maxdepth=2 headings=bullet headstart=2 showcats=1 showarts=1>Category:{{PAGENAME}}</ncl></big>
 
  
  
 
[[Category:Bacteria]][[Category:Gram_positive_bacteria]][[Category:Cocci]]
 
[[Category:Bacteria]][[Category:Gram_positive_bacteria]][[Category:Cocci]]

Revision as of 13:23, 24 May 2010


Overview

  • Cause suppurative infections in many different animals
  • Cause abscess formation and septicaemia
  • Cause mastitis, metritis, polyarthritis, meningitis
  • Primary or secondary infections following viral infection
  • Neonatal septicaemia related to maternal genital tract infection
  • Haemolytic streptococci of Lancefield group C are common inhabitants of the equine nasopharynx
  • Streptococcus zooepidemicus and S. equisimilis are usually non-pathogenic
  • Involved in peritonitis in pigs, pyothorax, osteomyelitis, catarrhal stomatitis
  • In infectious arthritis of sheep, arthritis in calves, arthritis in horses and arthritis in pigs
  • Often commensals on mucous membranes of upper respiratory and lower urogenital tract
  • Opportunistic infections


Characteristics

  • Gram positive cocci forming chains
  • Catalase negative, facultative anaerobes
  • Fastitidious - require enriched media such as blood or serum
  • Small haemolytic, translucent colonies, some mucoid
  • Catalase negative
  • Susceptible to desiccation


Identification

  • Beta haemolysis (complete with clear zones surrounding colonies)
  • Alpha haemolysis (partial with green zones surrounding colonies)
  • Lancefield grouping - serology based on group-specific polysaccharide in cell wall
  • Biochemical testing


Diagnosis

  • Swabs of pus or exudate cultured on blood agar and MacConkey agar
  • No growth on MacConkey except S. faecalis
  • PCR, Lancefield grouping and biochemical tests


Pathogenesis and Pathogenicity

  • Beta-haemolytic strains more pathogenic than alpha-haemolytic strains
  • Virulence factors include streptolysins, hyaluronidase, DNase, streptokinase and proteases
  • S. pyogenes, S. pneumoniae and some strains of S. equi have polysaccharide capsules which are antiphagocytic
  • S. pyogenes and S. equi have antiphagocytic cell wall M proteins