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38 Cards in this Set
- Front
- Back
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What is the major growth char for Streptococcus?
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Spherical, gram-positive cocci growing in CHAINS.
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What are the four major human pathogens in the genus Streptococcus?
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1) S. pyogenes
2) S. agalactica 3) S. pneumonia 4) Viridans streptococci |
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What's the difference between Lancefield Groups and Hemolysis classification?
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Lancefield is determined by surface antigens, hemolysis is determined by blood agar growth chars.
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What bacterial factor causes beta-hemolysis?
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Streptolysins S or O
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What bacterial factor causes alpha-hemolysis?
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Peroxides
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What important biochemical characteristic is used to ID Streptococcus?
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Catalase Test: all are catalase NEGATIVE
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Name the common term, hemolytics, and Lancfied for:
S. pyogenes |
GAS: Group A Beta-Hemo Lancefield A
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Name the common term, hemolytics, and Lancfied for:
S. agalactiae |
GBS: Group B Beta,Gamma Lancefield B
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Name the common term, hemolytics, and Lancfied for:
S. pneumoniae |
Pneumococcus Alpha Lancefield Not Detectable
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What are the major post-infection sequelae of GAS infection?
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Rheumatic Fever, Glomerulonephritis
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What's the major pathogenic trick of GAS/S. pyogenes?
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Disrupts opsonization and evades phagocytosis
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What surface protein aids GAS/S. pyogenes in colonization/adhesion?
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M Protein
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How does GAS/S. pyogenes avoid opsonization?
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C5A Peptidase
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What host antibody/serology test is used to detect GAS infection?
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ASO Titer, or anti-Streptolysin O AB test
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Does GAS have an exotoxin?
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Yes - Streptococcal pyrogenic exotoxin (SPE), linked to scarlet fever, TSS, and nec fasc
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What's the transmission method for GAS pharyngitis?
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Person-to-person via respiratory droplets or nasal secretions.
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Describe the symptoms of GAS Pharyngitis
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Abrupt onset, malaise, fever and HA. Incubation time approx. 2-4 days.
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Physical findings of GAS Pharyngitis?
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1) Hyperemic tonsilitis
2) tonsilar exudates 3) Oropharyngial petechiae |
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What major symptom is NOT FOUND in GAS Pharyngitis?
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Cough
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Gold standard for GAS Pharyngitis Dx?
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Throat Culture. (Clinical rapid strep against Lancefield antigen possible for empiric therapy.)
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What subcutaneous GAS infection involves the cheeks and forehead?
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Erysipelas
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What fast-moving GAS infection follows fascial planes?
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Necrotizing fasciitis
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What streptococcal pathogen has major impact on newborns?
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S. agalactiae - vertical transmission resulting in septicemia and meningitis
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What Genus Species is associated with GBS?
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Steptococcus agalactiae
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What are the adult clinical manifestations of GBS/S. agalactiae
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Chorioamnionitis, endometritis, UTI
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What's the definitive dx for neonatal GBS?
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CSF and blood culture, followed by latex agglutination test.
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I say alpha-hemolytic gram positive diplococci, you say...
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Streptococcus pneumoniae
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What's the major pathology found in Strep. pneumo infections?
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Immunogenic damage caused by host response to infection.
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What's the most common cause of septic meningitis in children less than two years of age?
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Streptococcus pneumoniae
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How does Streptococcus pneumonia take hold in the lung?
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Impaired defenses, such as smoking, chronic illness
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What's one of the most common bacterial isolates from acute otitis media?
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Streptococcus pneumonia (along with non-typable Haemophilus influenza)
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How is Strep. pneumo detected in the laboratory?
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Culture - alpha hemolytic, optochin sensitive
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Can Streptococcal pneumonia be prevented?
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Conjugated Purified Polysaccaride Vaccine available
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What bacterial/infective complication can result from dental work?
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Endocarditis caused by Streptococcus mutans
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What "Group D Strep" coccus is now classified on it's own?
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Enterococcus
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Enterococcus Characteristics?
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Gram positive
Catalase negative Gamma hemolytic Diplococci in short chains NORMAL FLORA in Intestine and Female GU |
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What normal gut flora bacteria causes highly resistant nosocomial/iatrogenic infections?
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Enterococcus ssp.
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What streptococcal bacteria is associated with colon cancer?
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Streptococcus bovis
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