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16 Cards in this Set
- Front
- Back
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What common feature do all Staph have? How is Staph aureus unique?
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All staph produce catalase, but only staph aureas produces coagulase.
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What bacteria cause caries?
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Strep mutans, mitis, salivarius
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What patterns do staph grow in? Strep?
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Staph - clusters. Strep - chains.
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Describe staph and strep:
1) Respiration 2) What they grow in the presence of 3) Special fermentation? 4) Produce? |
1) Respiration
Staph - aerobic/facultative anaerobic Strep - facultative anaerobic/anaerobic 2) Grow in the presence of: Straph - halophiles, 7.5% NaCl Strep - fastidious organisms, grow well on enriched media 3) Special fermentation Staph - none Strep - homolactic fermentation 4) Produce: Staph - catalase Strep - NO catalase Staph - catalse Strep - does not produce catalase |
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What is the main way you can differentiate between staph and strep? What is the importance of this?
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Catalase test - staph produces catalase and strep does not.
Catalse is important because it converts hydrogen peroxide into water and oxygen, which neutralize our body's defense systems (PMNs). |
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How are staph very unique in their growing conditions?
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They are one of the few organisms that love salt. Salt usually kills off most other bacteria.
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Why is strep doing homolactic fermentation important to us?
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This causes caries.
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Staph vs. Strep:
1) Colony size 2) Color 3) Hemolysis |
1) Colony size
Staph - large Strep - small 2) Color Staph - s. aureus = golden/cream. Non s. aureus = white Strep - white 3) Hemolysis Staph - Most beta hemolytic Strep - +/- hemolysis depending on species |
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How do you classify Strep?
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Hemolysis:
alpha - partial (virudans, green) beta - complete - MAJORITY gamma - none Lancefield system - based off C-substance antigen (cell wall carbohydrate) |
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A majority of strep exhibit what kind of hemolysis?
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Beta.
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What are the different types of Strep classified by the Lancefield system? What does each cause?
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Group A - Strep pyogenes - skin and throat infections, beta hemolytic.
Group B - Strep agalactiae - neonatal meningitis, beta hemolytic. Normal flora. Non-classifiable - 1) Viridans strep -Strep mutans - dental caries, alpha hemolysis. 2) Strep pneumoniae - bacterial pneumonia |
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What is an example of group B streptococcus?
Where is it found? What kind of hemolysis does it exhibit? How does this contrast Strep pyogenes hemolysis? What is it the most common cause of? What else does it cause in newborns? How do most of these diseases result? What is the DOC? |
Strep agalactiae.
Found in normal flora in GU, UR tracts. Beta hemloysis. Strep pyogenes has obvious, thick strip of beta hemolysis. Strep agalactiae only has a thin strip. Most common cause of neonatal morbidity and mortality, neontal meningitis. Also causes septicemia, pneumonia, and cellulitis in most newborns. Most result from mother-infant transmission during labor and delivery. DOC: Penicillin |
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Enterococcus faecalis:
Previously classified as? Structure? Commensals of where? Major cause of? Special things regarding treatemtn? |
Previous classified as Class D.
Gram + cocci in pairs or short chains. Gut commensals. Major cause of nosocomial infections - wound infections, UTI, endocarditis. HIGHLY RESISTANT. Vancomycin resistant. One of the most resistant bacteria. |
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Viridans streptococci:
Where do they come from? Where do they colonize? What are they classified as? What kind of hemolysis do they perform? What species are included? What diseases is it associated with? |
Comes from normal flora. Can colonize GI and GU tract.
Non-classifiable in Lancefield system. Alpha hemolytic. Oral streptococci included - Strep mutans, sobrinus, salivarius, mitis, sanguis, oralis. Also Strep pneumoniae. Associated diseases: caries and subacute bacterial endocarditis, especially in patients with existing heart damage. |
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What kind of problems do you see with the heart when you've been infected with viridians streptococci?
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Aortic valve dysfunction, tricuspid valve vegetations, mitral valve vegetations.
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List the 2008 AHA guidelines for endocarditis prophylaxis.
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Antibiotics should be given prior to dental therapy in patients with:
- Prosthetic valves, patients with prosthetic material used for cardiac valve repair - Previous infective endocarditis - Specific congenital conditions, implants - Cardiac transplant w/ valve regurgitation NO LONGER RECOMMENDED FOR: - Rheumatic heart disease - Mitral or aortic valve stenosis - Mitral valve prolapse - Congenital heart conditions - ventricular/atrial septal defects, hypertrophic cardiomyopathy |
