Difference between revisions of "Streptococci"
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− | # | + | {{review}} |
+ | |||
+ | {{toplink | ||
+ | |backcolour = | ||
+ | |linkpage =Bacteria | ||
+ | |linktext =BACTERIA | ||
+ | |pagetype=Bugs | ||
+ | }} | ||
+ | <br> | ||
+ | |||
+ | ===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 | ||
+ | *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 | ||
+ | |||
+ | |||
+ | ===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 | ||
+ | |||
+ | |||
+ | ===[[Respiratory Bacterial Infections - Pathology#Strangles|Strangles]]=== | ||
+ | |||
+ | *Epidemiology | ||
+ | **[[Respiratory Bacterial Infections - Pathology#Strangles|Strangles]] is a highly infectious disease of horses caused by ''Streptococcus equi'' subsp. ''equi'' | ||
+ | **[[Respiratory Bacterial Infections - Pathology#In Horses|upper respiratory tract disease of horses]] with fever and abscessation of regional lymph nodes | ||
+ | **Causes [[Nasal Cavity Inflammatory - Pathology#Strangles|rhinitis]], [[Nasopharynx Inflammatory - Pathology|pharyngitis]], lymphadenitis and [[Muscles Inflammatory - Pathology#Abscesses|myositis]] | ||
+ | **Outbreaks in groups of young horses | ||
+ | **Transmitted via purulent exudate discharging from upper respiratory tract or from lymph nodes | ||
+ | **Chronic, carrier state can occur with bacteria im the guttural pouch | ||
+ | **A mild, atypical form can occur | ||
+ | **''S. equi'' shed for 4 weeks beyond clinical resolution | ||
+ | |||
+ | *Clinical signs | ||
+ | **Incubation period 3 to 6 days | ||
+ | **Fever, depression, anorexia | ||
+ | **Purulent nasal discharge | ||
+ | **Swollen, painful regional lymph nodes, especially submandibular | ||
+ | **Abscessation and rupture of lymph nodes | ||
+ | **Guttural pouch empyema | ||
+ | **100% morbidity; 5% mortality | ||
+ | **Death can occur from pneumonia, breathing difficulties from swollen lymph nodes or [[Muscles Degenerative - Pathology#Ischaemia|purpura haemorrhagica]](an immune-mediated disease) | ||
+ | **Bastard strangle may occasionally occur, with abscessaation in many organs of the body | ||
+ | **''S. equi'' may be involved in [[Bacterial skin infections - Pathology#Systemic bacterial infections|cutaneous lesions]] | ||
+ | |||
+ | *Diagnosis | ||
+ | **Clinical signs and history | ||
+ | **Mucoid colonies with beta-haemolysis | ||
+ | **Sugar fermentation allows differentiation of ''S. equi'' from ''S. zooepidemicus'' and ''S. equisimilis'' | ||
+ | **PCR to detect asymptomatic carriers | ||
+ | |||
+ | *Treatment and control | ||
+ | **Penicillin administration to in-contact animals | ||
+ | **Isolation of affected animals | ||
+ | **Quaranteen in-coming animals | ||
+ | **Avoid overcrowding and mixing different age groups | ||
+ | **Disinfection of equipment | ||
+ | |||
+ | |||
+ | ===''Streptococcus suis''=== | ||
+ | |||
+ | *Meningitis, arthritis, septicaemia and [[Respiratory Bacterial Infections - Pathology#Streptococcal pneumonia|pneumonia]] of pigs | ||
+ | *Sporadic cases of endocarditis, neonatal deaths and abortion | ||
+ | *Carried in tonsils and nasal cavity of carrier pigs | ||
+ | *Outbreaks occur in intensively-reared herds with poor hygiene | ||
+ | *Carrier sows infect litters causing neonatal deaths | ||
+ | *Meningitis with fever, tremors, incoordination, opisthotonos and convulsions | ||
+ | *Treatment with penicillin; prophylactic long-acting penicillin for sows and piglets | ||
+ | *Suppurative conditions in cattle, sheep, horses, cats | ||
+ | *Septicaemia and meningitis in humans | ||
+ | |||
+ | |||
+ | ===Bovine streptococcal mastitis=== | ||
+ | |||
+ | *''S. agalactiae, S. dysgalactiae'' and ''S. uberis'' primarily cause mastitis | ||
+ | *Also ''S. pyogenes, S. zooepidemicus'' and ''Enterococcus faecalis'' can be involved | ||
+ | *''S. agalactiae'' colonises milk ducts causing persistent infections with acute outbreaks | ||
+ | *''S. dysgalactiae'' found in the oral cavity and on the skin of the udder causes acute mastitis | ||
+ | *''S. uberis'' inhabits normal skin, tonsils and vaginal mucosa, and causes mastitis without systemic signs | ||
+ | *Cause inflammation of mammary tissue and clots form in milk | ||
+ | *Milk samples are cultured on blood agar, Edward's medium and MacConkey agar for diagnosis | ||
+ | |||
+ | |||
+ | ===''S. equisimilis''=== | ||
+ | |||
+ | *Found on skin and vagina of horses | ||
+ | *Causes abscesses, endometritis and mastitis in horses | ||
+ | *Suppurative conditions in pigs, cattle, dogs, birds | ||
+ | |||
+ | |||
+ | ===''S. zooepidemicus''=== | ||
+ | |||
+ | *Colonises mucous membranes | ||
+ | *Causes mastitis, pneumonia, [[Paranasal Sinuses Inflammatory - Pathology|sinusitis]] and navel infections in horses | ||
+ | *''S. zooepidemicus'' can cause similar signs to [[Respiratory Bacterial Infections - Pathology#Strangles|strangles in horses]] and may accompany [[Bronchi and Bronchioles Inflammatory - Pathology#Chronic obstructive pulmonary disease (COPD)|COPD]] | ||
+ | *Secondary invador after [[Respiratory Viral Infections - Pathology#Equine influenza|equine influenza]] | ||
+ | *Colonises skin and mucous membranes of cattle, lambs, pigs and poultry and causes suppurative infections and septicaemia | ||
+ | * Can cause vascular fragility, leading to [[General Pathology - Haemostasis#Haemorrhagic Disease Due To Vascular Fragility|haemorrhagic disease]] | ||
+ | |||
+ | |||
+ | ===''Enterococcus faecalis''=== | ||
+ | |||
+ | *Colonises intestinal tract | ||
+ | *Causes opportunistic suppurative infections in many species | ||
+ | |||
+ | |||
+ | ===''S. canis''=== | ||
+ | |||
+ | *Found in vagina and anal mucosa of carnivores | ||
+ | *Neonatal septicaemia, suppurative infections, toxic shock syndrome | ||
+ | *In [[Bacterial skin infections - Pathology#Deep pyoderma|deep pyoderma]] and subcutaneous abscesses | ||
+ | |||
+ | |||
+ | ===''S. pneumoniae''=== | ||
+ | |||
+ | *Found in upper respiratory tract of primates | ||
+ | *Causes septicaemia, pneumonia and meningitis | ||
+ | *Pneumonia in guinea-pigs and rats | ||
+ | |||
+ | |||
+ | ===''S. porcinus''=== | ||
+ | |||
+ | *Submandibular lymphadenitis in pigs | ||
+ | |||
+ | |||
+ | |||
+ | * [[Peritoneal Cavity Inflammatory - Pathology#In pigs|peritonitis in pigs]] | ||
+ | *In [[Pleural Cavity & Membranes Inflammatory - Pathology#Pyothorax (Thoracic empyema)|pyothorax]] | ||
+ | * In [[Bones Inflammatory - Pathology#Osteomyelitis|osteomyelitis]] | ||
+ | *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]] | ||
+ | *In [[Cavity & Gingiva - Pathology#Catarrhal Stomatitis|catarrhal stomatitis]] |
Revision as of 16:42, 29 December 2008
This article has been peer reviewed but is awaiting expert review. If you would like to help with this, please see more information about expert reviewing. |
|
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
- 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
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
Strangles
- Epidemiology
- Strangles is a highly infectious disease of horses caused by Streptococcus equi subsp. equi
- upper respiratory tract disease of horses with fever and abscessation of regional lymph nodes
- Causes rhinitis, pharyngitis, lymphadenitis and myositis
- Outbreaks in groups of young horses
- Transmitted via purulent exudate discharging from upper respiratory tract or from lymph nodes
- Chronic, carrier state can occur with bacteria im the guttural pouch
- A mild, atypical form can occur
- S. equi shed for 4 weeks beyond clinical resolution
- Clinical signs
- Incubation period 3 to 6 days
- Fever, depression, anorexia
- Purulent nasal discharge
- Swollen, painful regional lymph nodes, especially submandibular
- Abscessation and rupture of lymph nodes
- Guttural pouch empyema
- 100% morbidity; 5% mortality
- Death can occur from pneumonia, breathing difficulties from swollen lymph nodes or purpura haemorrhagica(an immune-mediated disease)
- Bastard strangle may occasionally occur, with abscessaation in many organs of the body
- S. equi may be involved in cutaneous lesions
- Diagnosis
- Clinical signs and history
- Mucoid colonies with beta-haemolysis
- Sugar fermentation allows differentiation of S. equi from S. zooepidemicus and S. equisimilis
- PCR to detect asymptomatic carriers
- Treatment and control
- Penicillin administration to in-contact animals
- Isolation of affected animals
- Quaranteen in-coming animals
- Avoid overcrowding and mixing different age groups
- Disinfection of equipment
Streptococcus suis
- Meningitis, arthritis, septicaemia and pneumonia of pigs
- Sporadic cases of endocarditis, neonatal deaths and abortion
- Carried in tonsils and nasal cavity of carrier pigs
- Outbreaks occur in intensively-reared herds with poor hygiene
- Carrier sows infect litters causing neonatal deaths
- Meningitis with fever, tremors, incoordination, opisthotonos and convulsions
- Treatment with penicillin; prophylactic long-acting penicillin for sows and piglets
- Suppurative conditions in cattle, sheep, horses, cats
- Septicaemia and meningitis in humans
Bovine streptococcal mastitis
- S. agalactiae, S. dysgalactiae and S. uberis primarily cause mastitis
- Also S. pyogenes, S. zooepidemicus and Enterococcus faecalis can be involved
- S. agalactiae colonises milk ducts causing persistent infections with acute outbreaks
- S. dysgalactiae found in the oral cavity and on the skin of the udder causes acute mastitis
- S. uberis inhabits normal skin, tonsils and vaginal mucosa, and causes mastitis without systemic signs
- Cause inflammation of mammary tissue and clots form in milk
- Milk samples are cultured on blood agar, Edward's medium and MacConkey agar for diagnosis
S. equisimilis
- Found on skin and vagina of horses
- Causes abscesses, endometritis and mastitis in horses
- Suppurative conditions in pigs, cattle, dogs, birds
S. zooepidemicus
- Colonises mucous membranes
- Causes mastitis, pneumonia, sinusitis and navel infections in horses
- S. zooepidemicus can cause similar signs to strangles in horses and may accompany COPD
- Secondary invador after equine influenza
- Colonises skin and mucous membranes of cattle, lambs, pigs and poultry and causes suppurative infections and septicaemia
- Can cause vascular fragility, leading to haemorrhagic disease
Enterococcus faecalis
- Colonises intestinal tract
- Causes opportunistic suppurative infections in many species
S. canis
- Found in vagina and anal mucosa of carnivores
- Neonatal septicaemia, suppurative infections, toxic shock syndrome
- In deep pyoderma and subcutaneous abscesses
S. pneumoniae
- Found in upper respiratory tract of primates
- Causes septicaemia, pneumonia and meningitis
- Pneumonia in guinea-pigs and rats
S. porcinus
- Submandibular lymphadenitis in pigs
- peritonitis in pigs
- In pyothorax
- In osteomyelitis
- In infectious arthritis of sheep, arthritis in calves, arthritis in horses and arthritis in pigs
- In catarrhal stomatitis