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14 Cards in this Set
- Front
- Back
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Streptococci |
1. Gram-positive bacteria 2. Oval/spherical in shape (cocci) 3. Grow in pairs or chains 4. Catalase-negative 2H20 --> 2H2O + O2 5. Fastidious- require complex media for growth in lab 6. facultative anaerobes (grow both aerobically and anaerobically) 7. large, heterogeneous group of bacteria |
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Classification of Streptococci |
1. Hemolytic pattern on blood agar plates 2. Molecular studies designating species and sub-species 3. Lancefield group (serologic system based on the reaction of specific antisera w/ surface carbohydrate antigens) 4. Phenotypic traits |
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Lancefield Groups |
Only focus on A, B, Viridans, and No antigen group |
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Alpha-hemolytic |
S. pneumoniae (Optochin Sensitive; zone of inhibition) viridans streptococci (Optochin Resistant; no zone of inhibition) |
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Beta-hemolytic |
S. pyogenes aka Group A Strep (Bacitracin sensitive) S. agalactiae aka Group B Strep (Bacitracin Resistant) |
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S. Pneumoniae |
1. Alpha-hemolytic 2. Optochin sensitive 3. Lancefield classified 4. Significant global cause of illness and death 5. Commonly colonizes the human nasopharynx |
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Pneumococcal Pathogenesis and Virulence |
1. Transmitted via infected respiratory secretions/droplets 2. Colonization does not usually result in disease |
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Pneumococcal Capsule |
1. Protects against phagocytosis 2. 13 serogroups responsible for majority of human disease 3. Basis of pneumococcal vaccines |
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Pneumococcal Infections and Disease |
1. Non-invasive- otitis media and sinusitis 2. Invasive- pneumonia, meningitis, endocarditis |
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Non-Invasive Pneumococcal Disease- Otitis Media |
Middle Ear disease 1. Most common 2. Affects young children 3. follows a viral upper respiratory tract infection (URI) 4. acute onset of severe pain, fever, loss of hearing, swollen red and bulging tympanic membrane |
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Sinusitis |
Non-Invasive Pneumococcal Disease inflammation/ infection of the facial sinus cavities - complication of URIs - Facial pain, congestion, fever, and persistent nighttime cough |
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Pneumonia |
Invasive Pneumococcal Disease lung infection that inflames the alveoli (air sacs) - most common - Diagnosed by Gram's staining and culture of sputum - Considered invasive when blood cultures as positive |
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Meningitis |
Invasive Pneumococcal Disease inflammation of membranes surrounding the brain and spinal cord |
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S. pyogens |
1. GAS 2. Beta hemolytic 3. bacitracin sensitive 4. begin in the throat and skin |
