Lecture 12: Streptococcus Respiratory Infections and Mastitis Flashcards
Are streptoccci gram positive or negative
Positive
Streptococci are arranged in ___ or __
Pairs or chains
Are streptocci commensal organisms
Yes, found in upper respiratory tract, GI tract, lower urogenital track but become opportunistic pathogens
Streptococci are ___ anaerobes
Facultative
Are streptococci catalase positive or negative
Negative
What is the appearance of colonies for streptococci
Clear, gray, white or yellow with smooth and mucoid appearance
T or F: streptococci are fastidious
True
T or F: streptococci are capnophiles
True
T or F: streptococci have hemolytic patterns
True
How are streptococci classified
Lance field classification based on group specific cell wall carbohydrate
What test can be performed to determine lancefield group
Latex agglutination test
what lancefield group is this streptococci
B- clumping
What is the function of the polysaccharide capsule
Inhibits phagocytosis
Produced smooth/mucoid appearance of capsules
What are the functions of peptidoglycan and LTA
Potent pyrogens
Induce cytokine secretion
LTA is an adhesin
What is the function of fimbrial M protein
Adhesin
Inhibits complement
Antiphagocytic
Associated with post-streptococcal immune response
What are the function of hemolysins and what ones are found in streptococci
Destroy RBC’s, responsible for B-hemolysis
Streptolysins O and S
What are the function of DNases
Degrades DNA, liquifies pus to facilitate spread, evade immune responses
What are the function of hyaluronidases
Break down hyaluronic acid in ECM and facilities spread
What is the function of streptokinase/ Fibrinolysis
Dissolves blood clots and facilitates spread
What do streptococcal pyrogenic exotoxins (Spe) do and what are the relevant types
SpeA and SpeC are superantigens that result in non-specific activation of T cells—> cytokine storm—> toxemia
Severe mastitis is often due to gram ___bacteria
Negative—> endotoxemia
What streptococcal species is responsible for contagious bovine mastitis
S. Agalactiae
S. Agalactiae causes what type of hemolysis
Beta
Is S. Agalactiae CAMP negative or positive
Positive
Which organism is an intermediate pathogen in bovine mastitis
S. Dysgalactiae
What hemolytic pattern does S. Dysgalactiae cause
Alpha
Is S. Dysgalactiae CAMP positive or negative
Negative
What streptococcal organism causes environmental mastitis
S. Uberis
What hemolytic pattern does S. Uberis have
Alpha
Is S. Uberis CAMP negative or positive
Negative
How does the CAMP test work for S. Agalactiae
CAMP factor produced by S. Agalactiae which enhances the hemolysin activity of staphylococcus aureus and produces an arrowhead shaped hemolysis
What are the 3 mediums on the tri-plate and what do they test for
- MacConkey-gram negative
- Factor- gram positive
- MTKT- streptococcus
What is strangles
Equine distemper in horses causes by S. Equi resulting in infection of upper respiratory tract
What are some signs of strangles
Purulent oculonasal discharge, painful abscesses in regional LN
Strangles causes abscesses in regional LN which can result in what 3 signs
- Difficulty swallowing
- Extended head and neck
- Difficulty breathing
Abscess rupture in strangles leads to ___
- Purulent exudate
- Guttural pouch emphysema
- Chondroids
How is streptococcus equi transmitted
Nasal secretions or purulent discharge from abscess via direct or indirect
What is the incubation period for S. Equi
3 days to 2 weeks but horses can remain infectious for several weeks and become chronic carriers
What is the pathogensis of S. Equi
- Entry of pathogen
- Attach to crypts of lingual and palatile tonsils (adhesins and capsules)
- mandibular an suprapharyngeal LN
- Failure of neutrophils to kill (SeM protein, hyaluronic acid)
- Streptolysin and streptokinases- abscess
- Spread to other organs
- Bastard strangles
What is purpura hemorrhagica
Complication of S. Equi following infection or vaccination. Immune response against bacterial M protein
What type of hypersensitivity reaction is Purpura hemorrhagica
Type III—> immune complex deposition in vessel walls
What are some clinical signs of purpura hemorrhagic
Edema, vasculitis, mucosal hemorrhages
Vasculitis that occurs in purpura hemorrhagica is mainly due to release of damaging enzymes by what cell type
Neutrophils—> can’t phagocytize so release lyric enzymes—> tissue damage
How do you diagnose S. Equi
- Culture- gram positive streptococci and B-hemolysis
- PCR- detection of species specific M protein (SeM)
What do you expect to see on culture of S. Equi
Gram positive streptococci and Beta-hemolysis
What test can you do to differentiate between S.equi spp and other streptococcal species
PCR detection of SeM protein
What is treatment for S. Equi
- Supportive care
- Anti-inflammatory medications
- Antibiotics contraindicated but if needed use penicillin
Why are antibiotics contraindicated in tx of S. Equi
Hard to penetrate abscess and slow resolution of disease and can risk spread to other LN
How do you manage S. Equi
- Quarantine
- Disinfect
- Vaccines
What organism can cause hemorrhagic pneumonia
S. Equi zooepidemicus
The initial signs of S. Equi zooepidemicus are similar to __
Kennel cough
The rapid onset of deterioration from S. Equi zooepidemicus is due to what
Cytokine storm—> pro inflammatory cytokines released
S. Equi zooepidemicus is associated with what type of settings
Kennel
How does S. Equi zooepidemicus spread
Direct contact
T or F: S. Equi zooepidemicus is zoonotic
True, but rare
What is pathogensis of S. Equi zooepidemicus
- Adherence
- Capsule- antiphagocytic
- SzM protein- antiphagocytic, inhibits complement
- Secrete toxin enzymes
- Superantigens—> MHCII and T cell binding—> cytokine storm
What type of T cell is secreting pro-inflammatory cytokines
Helper T cells
How do you diagnose S. Equi zooepidemicus
- Culture- gram positive streptococci, Beta-hemolysis, histopathology
- PCR detection of SodA
What do you expect to see on culture of S. Equi zooepidemicus
Gram positive streptococci, beta-hemolysis
What is the treatment for S. Equi zooepidemicus
Antibiotics- B-lactams
What organism causes fading puppy syndrome, secondary pneumonia and neonatal septicemia
Streptococcus canis
How do you dx Streptococcus canis
- Culture- gram positive streptococci, beta-hemolysis
What do you expect to see on culture of S. Canis
Gram positive streptococci and B-hemolysis
What is tx for S. Canis
If infectious- antibiotics- B-lactams
Which organism can cause meningitis in pigs
Streptococcus suis
S. Suis most often occurs in what pigs
Young post weaned pigs
What are the earliest clinical signs of S. Suis
Fever accompanied by septicemia
What are the clinical signs of meningitis caused by S. Suis in pigs
Ears back, eyes squinting, unusual stances, convulsions, other neurological signs
What lesions are associated with S. Suis
Lymphadenopathy, meningitis, arthritis, endocarditis
How is S. Suis transmitted
Healthy carrier sows and their offspring because S. Suis is prevalent in oral cavity and vaginal canal
What stereotype of S. Suis is most virulent and most frequently isolated from diseased pigs
Stereotype 2
How do you identify the serotypes of S. Suis
Capsule polysaccharides
What is the pathogensis of S. Suis
- Enter upper respiratory tract
- Adhesins
- Proteins that allow immune evasion
- S. Suis adenosine synthase- inhibits PMN activity
- IgG degrading enzymes
- Factor H-binding surface protein: inhibits phagocytosis
What proteins in S.suis allow immune evasion and what do they do
- S. Suis adenosine synthase (Ssads): inhibit PMN activity—> inhibit neutrophils
- IgG degrading enzymes
- Factor H binding surface proteins: inhibits phagocytosis
How does S. Suis spread to other tissues
Hematogenous
How do you diagnose S. Suis
- Gram positive streptococci
- Alpha hemolysis on blood agar
- Histopathology
What do you expect to see on culture of S. Suis
Gram positive streptococci and alpha- hemolysis
What is tx for S. Suis
Antibiotics for meningitis: B-lactams
T or F: S. Suis is zoonotic
True
What is answer in photo
E. S. Agalactiae
what is answer in photo
A. S. Uberis
what is. Answer in photo
C. Catalase negative, alpha hemolytic
What is answer in photo
D. Hemorrhagic pneumonia
What is answer in photo
A. Streptococcal pyrogenic exotoxin A