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*Cause suppurative infections in many different animals
*Cause suppurative infections in many different animals
*Cause abscess formation and septicaemia
*Cause mastitis, metritis, polyarthritis, meningitis
*Cause mastitis, metritis, polyarthritis, meningitis
*Often commensals on mucous membranes of upper respiratory and lower urogenital tract
*Opportunistic infections
*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
*Small haemolytic, translucent colonies, some mucoid
*Catalase negative
*Catalase negative
*Susceptible to desiccation
*Susceptible to desiccation
===Pathogenicity===
===Pathogensis 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
===Clinical infections===
===Clinical infections===
*Primary or secondary infections following viral infection
*Neonatal septicaemia related to maternal genital tract infection
*Strangles
**Highly infectious disease of horses caused by ''Streptococcus equi'' subsp. ''equi''
**Upper respiratory tract disease with fever and abscessation of regional lymph nodes
**Outbreaks in groups of young horses
**
===Diagnosis===
===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