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31 Cards in this Set
- Front
- Back
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Corynebacterium diphtheria
a. morphology b. grows on? |
a. gram + bacili, unencapsulated, non-spore
b. Loefflers, media with potassium tellurite |
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Corynebacterium diphtheria
Clinical features? |
Psuedomembrane over tonsils -- gray, leathery, DO NOT REMOVE
Bull neck - pseudomembrane + cervical lympadenopathy + neck swelling --> upper airway obstruction Can also lead to myocarditis, neuropathies |
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What is the nature of the toxin of Corynebacterium diphtheria?
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AB
B - targets cells A - ADP ribosylates EF2, inactivating it |
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What is contained in the DTaP vaccine?
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Toxoid of Corynebacterium diphtheria, tetanus, and inactivated pertussus
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When should DTap Vaccine be given?
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2 mo, 4mo, 6mo, 15-18mo, 4-6 yrs
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Streptococcus
a. morphology b. biochem |
a. gram + cocci in chains
b. catalase - |
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Streptococcus
types of hemolysis? |
alpha - incomplete, green
beta - total gamma - not at all |
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What are 2 types of Streptococcus that do alpha hemolysis?
One type of gamma? |
Streptococcus pneumoniae, viridans
Enterococcus |
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What is the number one cause of strep throat?
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Group A strep - S. pyogenes
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What is one way to tell the difference between GABHS and other beta hemolytic streps?
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GABHS is bacitracin sensitive
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How is GABHS transmitted?
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Saliva/nasal discharge
Food |
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GABHS
Virulence factors responsible for adherance? |
1. M protein - keratinocytes
2. lipotechoic acid 3. fibronectin binding proteins 4. hyaluronate capsule - CD44 |
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GABHS
Virulence factors responsible for immune evasion? |
1. M protein - antiphagocytic
2. capsule - barrier to complement 3. Ig binding proteins - Fc region 4. C5a peptidase - cleaves C5, prevents neutrophil recruitment |
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GABHS
Virulence factors responsible for invasion and spread? |
1. Spe B protease - degrades tissues
2. Streptolysins 3. DNAses - degrades DNA from lysed cells 4. Streptokinase - degrades clots by activating plasminogen 5. Hyaluronidase |
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GABHS
Virulence factors responsible for toxicity and spread? |
1. Superantigens --> activates T cells
2. Spe (pyogenic exotoxins) |
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What are 2 methods of host immunity to GABHS?
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1. opsonophagocytosis
2. specific antibodies against the M protein |
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What are 3 methods for diagnosing GABHS?
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1. Rapid antigen detection - minutes
-Latex agglutination or optical immunoassay 2. Cutlure - gram pos cocci in chains, beta-hemolytic 3. serology - anti-streptolysin O, anti-DNAse B |
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Acute diseases of GABHS
a. Suppurative b. Toxin-mediated |
a. pharyngitis, skin/soft tissue infection
b. Scarlet fever, strep shock |
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Delayed diseases of GABHS
a. following a pharyngeal infection b. following a skin infection |
a. Rheumatic fever, glomerulonephritis
b. glomerulonephritis |
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What are some clinical symptoms of pharyngitis?
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Acute sore throat, fever, nausea, vomiting, abdominal pain
tender cervical lymph nodes tonsils enlarged, red strawberry tongue, petechiae |
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What are 2 complications of GABHS pharyngitis?
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Tonsillar abscess
Cervical adenitis --> abscess drain |
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How do you diagnose Pharyngitis?
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Rapid strep test, can throat culture
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What is the treatment for strep pharyngitis?
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Penicillin if severe
oral penicillin/amoxicillin for 10 days |
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What happens in Scarlet fever?
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Toxin-medated condition
Fever, sandpaper rash (circumoral pallor), patia's lines, white --> strawberry tongue |
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What causes acute rheumatic fever?
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Delayed sequelae of GABHS pharyngitis
immune reaction - Abs cross react with heart/muscle/joints |
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What are the 5 major Jones criteria for diagnosing ARF?
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1. carditis
2. polyarthritis 3. Chorea 4. Erythema margniatum 5. Subcutaneous nodules |
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Minor Jones criteria for ARF
a. clinical b. labs |
a. arthralgia, fever
b. acute phase reactants, elevated ESR, increase in c-reactive protein, leukocytosis, prolonged PR interval |
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What is the requirement for diagnosing ARF?
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2 major or 1 major+2 minor
Need evidence of GABHS pharyngitis previously |
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What happens in acute glomerulonephritis?
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Follows skin or pharyngitis infection
ICs or anti strep Abs directly cause injury to glomerulus |
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acute glomerulonephritis
Symptoms |
dark urine, headache, back pain, edema, hypertension
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How do you treat glomerulonephrits?
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Treat symptoms (fluid retention, HT)
Treat residual bacterial infection with penicillin |
