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#REDIRECT[[:Category:Streptococcus species]]
 
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|backcolour =
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|linkpage =Bacteria
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|linktext =BACTERIA
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|pagetype=Bugs
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<br>
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===Overview===
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*Cause suppurative infections in many different animals
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*Cause abscess formation and septicaemia
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*Cause mastitis, metritis, polyarthritis, meningitis
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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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*Often commensals on mucous membranes of upper respiratory and lower urogenital tract
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*Opportunistic infections
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===Characteristics===
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*Gram positive cocci forming chains
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*Catalase negative, facultative anaerobes
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*Fastitidious - require enriched media such as blood or serum
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*Small haemolytic, translucent colonies, some mucoid
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*Catalase negative
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*Susceptible to desiccation
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===Identification===
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*Beta haemolysis (complete with clear zones surrounding colonies)
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*Alpha haemolysis (partial with green zones surrounding colonies)
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*Lancefield grouping - serology based on group-specific polysaccharide in cell wall
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*Biochemical testing
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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
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===[[Respiratory Bacterial Infections - Pathology#Strangles|Strangles]]===
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*Epidemiology
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**[[Respiratory Bacterial Infections - Pathology#Strangles|strangles]] is a 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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**Transmitted via purulent exudate discharging from upper respiratory tract or from lymph nodes
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**Chronic, carrier state can occur with bacteria im the guttural pouch
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**A mild, atypical form can occur
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**''S. equi'' shed for 4 weeks beyond clinical resolution
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*Clinical signs
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**Incubation period 3 to 6 days
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**Fever, depression, anorexia
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**Purulent nasal discharge
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**Swollen, painful regional lymph nodes, especially submandibular
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**Abscessation and rupture of lymph nodes
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**Guttural pouch empyema
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**100% morbidity; 5% mortality
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**Death can occur from pneumonia, breathing difficulties from swollen lymph nodes or purpura haemorrhagica (an immune-mediated disease)
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**Bastard strangle may occasionally occur, with abscessaation in many organs of the body
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*Diagnosis
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**Clinical signs and history
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**Mucoid colonies with beta-haemolysis
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**Sugar fermentation allows differentiation of ''S. equi'' from ''S. zooepidemicus'' and ''S. equisimilis''
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**PCR to detect asymptomatic carriers
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*Treatment and control
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**Penicillin administration to in-contact animals
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**Isolation of affected animals
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**Quaranteen in-coming animals
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**Avoid overcrowding and mixing different age groups
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**Disinfection of equipment
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===''Streptococcus suis''===
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===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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===Treatment===
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===Control===
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*Haemolytic streptococci of Lancefield group C are common inhabitants of the equine nasopharynx
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*''Streptococcus zooepidemicus'' and ''S. equisimilis'' are usually non-pathogenic
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*''S. equi'' is more pathogenic and is the cause of [[Respiratory Bacterial Infections - Pathology#Strangles|strangles]] with [[Nasal Cavity Inflammatory - Pathology#Strangles|rhinitis]], [[Nasopharynx Inflammatory - Pathology|pharyngitis]], lymphadenitis, [[Muscles Inflammatory - Pathology#Abscesses|myositis]]
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*''S. equi'' may be involved in [[Bacterial skin infections - Pathology#Systemic bacterial infections|cutaneous lesions]]
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[[Respiratory Bacterial Infections - Pathology#In Horses|URT inflammation in horses]]
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* [[Peritoneal Cavity Inflammatory - Pathology#In pigs|peritonitis in pigs]]
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*''S. zooepidemicus'' can cause similar signs to [[Respiratory Bacterial Infections - Pathology#Strangles|strangles in horses]], may accompany [[Bronchi and Bronchioles Inflammatory - Pathology#Chronic obstructive pulmonary disease (COPD)|COPD]]
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*May cause [[Paranasal Sinuses Inflammatory - Pathology|sinusitis]] in horses
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* Can cause vascular fragility, leading to [[General Pathology - Haemostasis#Haemorrhagic Disease Due To Vascular Fragility|haemorrhagic disease]].
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*Secondary invadors after [[Respiratory Viral Infections - Pathology#Equine influenza|Equine influenza]]
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*''S. suis'' in [[Respiratory Bacterial Infections - Pathology#Streptococcal pneumonia|pneumonia]] of pigs
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*In [[Pleural Cavity & Membranes Inflammatory - Pathology#Pyothorax (Thoracic empyema)|pyothorax]]
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* In [[Bones Inflammatory - Pathology#Osteomyelitis|osteomyelitis]]
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*In infectious [[Joints Inflammatory - Pathology#In Sheep|arthritis of sheep]], [[Joints Inflammatory - Pathology#In Cattle|arthritis in calves]], [[Joints Inflammatory - Pathology#In Horses|arthritis in horses]] and [[Joints Inflammatory - Pathology#In Pigs|arthritis in pigs]]
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*In horses sometimes [[Muscles Degenerative - Pathology#Ischaemia|purpura haemorrhagica]] follows, especially during recovery from [[Respiratory Bacterial Infections - Pathology#Strangles|strangles]]
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*In [[Cavity & Gingiva - Pathology#Catarrhal Stomatitis|catarrhal stomatitis]]
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*In [[Bacterial skin infections - Pathology#Deep pyoderma|deep pyoderma]] and subcutaneous abscesses
 
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