Difference between revisions of "Staphylococcus spp."
Jump to navigation
Jump to search
(Redirected page to Category:Staphylococcus species) |
|||
(22 intermediate revisions by 3 users not shown) | |||
Line 1: | Line 1: | ||
− | # | + | <big><center>[[Infectious agents and parasites|'''BACK TO INFECTIOUS AGENTS AND PARASITES''']]</center></big> |
+ | <big><center>[[Bacteria|'''BACK TO BACTERIA''']]</center></big> | ||
+ | |||
+ | *Gram positive cocci | ||
+ | |||
+ | * [[General Pathology - Oedema#Permeability type|Permeability types of pulmonary oedema]]. | ||
+ | |||
+ | * Can cause haemorrhagic disease by [[General Pathology - Haemostasis#Secondary Thrombocytopenic Disease|secondary thrombocytopenic disease]]. | ||
+ | |||
+ | *May infect [[Joints - inflammatory#In Sheep|joints of sheep]] or become complication of '''tick-borne fever''', also [[Joints - inflammatory#In Pigs|arthritis in pigs]], [[Joints - inflammatory#In Dogs|dyscospondylitis in dogs]] | ||
+ | |||
+ | *''Staphylococcus'' spp. in [[Bacterial skin infections#Impetigo|impetigo]] | ||
+ | *In [[Bacterial skin infections#Deep pyoderma|deep pyoderma]], esp. ''S. intermedius'' | ||
+ | |||
+ | |||
+ | ==Staphylococcus hyicus== | ||
+ | *Pigs - '''greasy pig disease''' | ||
+ | *Exudative epidermitis due to ''Staphylococcus hyicus'' is a worldwide problem in piglets. | ||
+ | *The organism can often be isolated from the mucosa and skin of healthy adult pigs, and can persist in the environment for long periods. | ||
+ | *Disease occurs only in young piglets up to about 35 days of age. | ||
+ | *Passive transfer of antibodies from immune sows and development of immunity with age appear to adequately protect against disease. | ||
+ | *Piglets from non-immune sows are predisposed. | ||
+ | *Skin trauma, such as due to fighting, allowing entry of infective organisms is also considered a risk factor in this disease. | ||
+ | |||
+ | ===[[Bacterial skin infections#Greasy pig disease|Pathology]]=== | ||
+ | |||
+ | |||
+ | ===Pathogenesis=== | ||
+ | *''Staphylococcus hyicus'' produces an exfoliative toxin of approximately 30 kDa that causes separation of cells in the upper stratum spinosum resulting in rapid intraepidermal spread of organisms. | ||
+ | *Death of affected piglets is common and is attributed to dehydration, septicemia, or both. | ||
+ | *This porcine disorder has been likened to “scalded skin syndrome” in human neonates, due to skin infection by exfoliative toxin-producing ''Staphylococcus aureus''. | ||
+ | |||
+ | ===Differential diagnosis=== | ||
+ | *mange (Sarcoptes scabiei var. suis) | ||
+ | *swine parakeratosis (zinc and essential fatty acid deficiency) | ||
+ | *porcine juvenile pustular psoriasiform dermatitis (collarettes or rings typically on the ventrum of young pigs) | ||
+ | *dermatosis vegetans (associated with a giant cell pneumonia) | ||
+ | *dermatophytosis (most commonly Microsporum nanum) | ||
+ | |||
+ | ==Staphylococcus aureus== | ||
+ | |||
+ | * May cause [[Intestines - disease due to pathogens#Staphylococcus|gastroenteritis]] in small animals. | ||
+ | *[[Muscles - inflammatory#Botryomycosis|Botryomycosis]] in muscles | ||
+ | *In botryomycosis in [[Bacterial skin infections#Bacterial granulomatous dermatitis|skin]] | ||
+ | |||
+ | ===Overview=== | ||
+ | |||
+ | *Commensals on skin and mucous membranes of animals and man | ||
+ | *Enodgenous or exogenous infections | ||
+ | *Opportunistic pyogenic infections associa | ||
+ | *Coagulase-positive 'S. aureus'' and ''S. intermedius'' as well as ''S. hyicus'' are important pathogens of animals | ||
+ | *Fairly stable in environment | ||
+ | *Strains selective for particular species | ||
+ | |||
+ | |||
+ | ===Characteristics=== | ||
+ | |||
+ | *Clusters of Gram-positive cocci | ||
+ | *At least 30 species | ||
+ | *Facultative anaerobes | ||
+ | *Catalase positive, oxidase negative, non-motile | ||
+ | *Virulent strains are coagulase positive | ||
+ | *Grow on non-enriched media | ||
+ | *White or golden colonies | ||
+ | *''S. aureus'' and ''S. intermedius'' produce double haemolysis; they produce alpha-haemolysin and beta-haemolysin | ||
+ | *Alpha-haemolysin prouces a narrow zone of complete haemolysis, whereas beta-haemolysin produces a wide zone of incomplete haemolysis | ||
+ | *Haemolysins act as toxins | ||
+ | *''S. hyicus'' is non-haemolytic | ||
+ | *Coagulase-negative strains vary in ability to cause haemolysis | ||
+ | *Slide test to detect bound coagulase (clumping factor) on surface of bacteria; bacteria clump within 1-2 minutes | ||
+ | *Tube test detects free coagulase, secreted by bactera; positive result indicated by clot formation in tube following 24-hour incubation | ||
+ | *Biochemical tests to differentiate ''S. aureus'' and ''S. intermedius'' | ||
+ | *PCR to differentiate species | ||
+ | |||
+ | |||
+ | ===Pathogenesis and pathogenicity=== | ||
+ | |||
+ | *Cause suppurative lesions | ||
+ | *Trauma or immunosuppression predispose to infection | ||
+ | *Capsular polysaccharide, teichoic acids and potein A prevent opsonisation and therefore phagocytosis | ||
+ | *Cell wall proteins bind fibronectin and fibrinogen, allowing bacteria to attched to damaged tissues | ||
+ | *Coagulase, DNase and protein A production mark pathogenicity | ||
+ | |||
+ | |||
+ | ===Diagnosis=== | ||
+ | |||
+ | *Clusters of bacteria in Gram-stained smears of pus | ||
+ | *Culture on selective blood agar and MacConkey agar | ||
+ | *No growth on MacConkey | ||
+ | *Colony characteristics, haemolysis, catalase and coagulase production | ||
+ | *Phage typing for epidemiological studies | ||
+ | |||
+ | |||
+ | === |
Revision as of 15:19, 20 July 2008
- Gram positive cocci
- Can cause haemorrhagic disease by secondary thrombocytopenic disease.
- May infect joints of sheep or become complication of tick-borne fever, also arthritis in pigs, dyscospondylitis in dogs
- Staphylococcus spp. in impetigo
- In deep pyoderma, esp. S. intermedius
Staphylococcus hyicus
- Pigs - greasy pig disease
- Exudative epidermitis due to Staphylococcus hyicus is a worldwide problem in piglets.
- The organism can often be isolated from the mucosa and skin of healthy adult pigs, and can persist in the environment for long periods.
- Disease occurs only in young piglets up to about 35 days of age.
- Passive transfer of antibodies from immune sows and development of immunity with age appear to adequately protect against disease.
- Piglets from non-immune sows are predisposed.
- Skin trauma, such as due to fighting, allowing entry of infective organisms is also considered a risk factor in this disease.
Pathology
Pathogenesis
- Staphylococcus hyicus produces an exfoliative toxin of approximately 30 kDa that causes separation of cells in the upper stratum spinosum resulting in rapid intraepidermal spread of organisms.
- Death of affected piglets is common and is attributed to dehydration, septicemia, or both.
- This porcine disorder has been likened to “scalded skin syndrome” in human neonates, due to skin infection by exfoliative toxin-producing Staphylococcus aureus.
Differential diagnosis
- mange (Sarcoptes scabiei var. suis)
- swine parakeratosis (zinc and essential fatty acid deficiency)
- porcine juvenile pustular psoriasiform dermatitis (collarettes or rings typically on the ventrum of young pigs)
- dermatosis vegetans (associated with a giant cell pneumonia)
- dermatophytosis (most commonly Microsporum nanum)
Staphylococcus aureus
- May cause gastroenteritis in small animals.
- Botryomycosis in muscles
- In botryomycosis in skin
Overview
- Commensals on skin and mucous membranes of animals and man
- Enodgenous or exogenous infections
- Opportunistic pyogenic infections associa
- Coagulase-positive 'S. aureus and S. intermedius as well as S. hyicus are important pathogens of animals
- Fairly stable in environment
- Strains selective for particular species
Characteristics
- Clusters of Gram-positive cocci
- At least 30 species
- Facultative anaerobes
- Catalase positive, oxidase negative, non-motile
- Virulent strains are coagulase positive
- Grow on non-enriched media
- White or golden colonies
- S. aureus and S. intermedius produce double haemolysis; they produce alpha-haemolysin and beta-haemolysin
- Alpha-haemolysin prouces a narrow zone of complete haemolysis, whereas beta-haemolysin produces a wide zone of incomplete haemolysis
- Haemolysins act as toxins
- S. hyicus is non-haemolytic
- Coagulase-negative strains vary in ability to cause haemolysis
- Slide test to detect bound coagulase (clumping factor) on surface of bacteria; bacteria clump within 1-2 minutes
- Tube test detects free coagulase, secreted by bactera; positive result indicated by clot formation in tube following 24-hour incubation
- Biochemical tests to differentiate S. aureus and S. intermedius
- PCR to differentiate species
Pathogenesis and pathogenicity
- Cause suppurative lesions
- Trauma or immunosuppression predispose to infection
- Capsular polysaccharide, teichoic acids and potein A prevent opsonisation and therefore phagocytosis
- Cell wall proteins bind fibronectin and fibrinogen, allowing bacteria to attched to damaged tissues
- Coagulase, DNase and protein A production mark pathogenicity
Diagnosis
- Clusters of bacteria in Gram-stained smears of pus
- Culture on selective blood agar and MacConkey agar
- No growth on MacConkey
- Colony characteristics, haemolysis, catalase and coagulase production
- Phage typing for epidemiological studies