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Which types of infection are associated with infections of the URT?
Rhinitis, sinusitis, oral cavity infections, pharyngitis, laryngeotrachobronchitis, epiglottitis
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Which two pathogens are associated with infections of the URT?
- Streptococcus pyogenes
- Corynebacterium diphtheriae
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Which infections are associated with infections of the LRT?
Bronchitis, bronchiolitis, pneumonia
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Which pathogen is associated with infections of the LRT?
Bordetella pertussis
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Which bacteria are common normal flora of the URT?
- Corynebacterium (diphtheroids)
- HaemophilusÂ
- Moraxella
- Neisseria
- Staph
- Strep
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Which pathogen is also known as group A strep?
Streptococcus pyogenes
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What are the 3 mechanisms of disease caused by S. pyogenes?
- Pyogenic inflammation
- Exotoxins/hemolysin production
- Immunologic
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Which adhesins are associated with S. pyogenes?
- M protein
- F (fibrinonectin) protein
- Collagen binding protein
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What are the antiphagocytic factors associated with S. pyogenes?
- Capsule (contains hyaluronic acid)
- M protein
- C5a peptidase
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Which enzymes does S. pyogenes contain that contributes to its virulence?
- Streptolysin O and S (lyse red blood cells)
- Streptokinase (activates plasminogen to plasmin to dissolve clots)
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What is the number one bacterial agent of pharyngitis?
S. pyogenes
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What are three secondary complications associated with S. pyogenes?
Scarlet fever, rheumatic fever, acuteglomerulonephritis
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How is S. pyogenes diagnosed in the lab?
Beta hemolytic colonies, catalase negative, Baitracin susceptible, Latex agglutination (group A positive)
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Are Streptococcus Catalase positive or negative?
Negative
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Are Staphylococcus Catalase positive or negative?
Positive
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Corynebacterium diphtheriae- gram and shape?
Gram positive rods, pleomorphic
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What is the main virulence mechanism of C. diphtheriae?
- Exotoxin productionÂ
- (AB toxin; B binds to heparin-binding epidermal growth factor, A inactivates EF-2 to inhibit protein synthesis)
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What are the clinical manifestations of diphtheria?
Sore throat, painful swallowing, pseudomembrane formation (breathing problems), regional lymphoadenopathy (bull neck appearance)
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Which tests are used to detect the diptheria toxin?
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Bordetella pertussis- gram and shape?
Gram negative coccobacilli
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What are the virulence mechanisms of B. pertussis?
- -Adheres to ciliated epithelial cells in trachea
- -Toxin production
- -Tissue destruction
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What are the three stages of symptoms associated with Pertussis?
- 1. Common cold symptoms (most contagious stage)
- 2. Paroxysmal cough (inspiratory whoop)
- 3. Convalescent stage
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Mycobacterium tuberculosis- gram and shape?
- Does not gram stain
- Acid fast bacillus
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What are the two types of acid fast stains?
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What are the steps in acid fast staining?
- Primary stain= carbofuchsin
- Decolorizer= acid alcohol
- Counter stain= methylene blue
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What are the unique features of the Mycobacterial cell wall?
Lipoarabinomannan and mycolic acid
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What are the main virulence mechanisms of Mycobacterium tuberculosis?
- Mycolic acid
- Facultative intracellular pathogen (in macrophages)
- Induces hypersensitivity (DTH)
- Cord factor
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What is the role of the cord factor found in M. tuberculosis?
- Causes cording of cells microscopically
- May inhibits PMNs
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