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25 Cards in this Set
- Front
- Back
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What are the bacterial characteristics of S. pyogenes? What are its growth characteristics in culture?
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*G+ cocci
*B-hemolytic *sensitive to bacitracin (A disk) |
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One of the Strep species can cause 3 different skin or fascia infections. What is the agent and what are the infections?
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*S. pyogenes (GAS)
*impetigo *cellulitis *necrotizing fasciitis |
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What is the most common manifestation of S. pyogenes in infected children? What are the symptoms?
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*strep throat
*pharyngitis, tonsillar exudate, fever *may or may not include scarlett fever rash |
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Antibiotic therapy of strep throat is generally indicated, even in mild cases, to prevent post-infection sequelae. What are these sequelae and how are they caused?
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*AGN and rheumatic fever
*the body generates antibodies that are cross-reactive to the bacterial M-protein and cardiac and renal epitopes |
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Name 3 endogenous (i.e. NOT exotoxins) virulence factors associated with S. pyogenes. How does each contricute to pathogenesis?
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*M-protein: antiphagocytic, adhesin
*hyaluronic capsule: antiphagocytic *F protein: binds fibronectin |
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What's the function of Streptolysin O and and C5a peptidase in S. pyogenes?
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*streptolysin O: direct tissue damage
*C5a peptidase: destroys complement |
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What are the 3 Spe exotoxins? What does each do?
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*Spe A & C: superAgs; associated with scarlett fever and STSS
*Spe B: protease associated with necrotizing fasciitis |
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What is the recommended treatment for S. pyogenes? What drug is this bug resistant to?
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*treat with PCN
*resistant to macrolides |
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What are the bacterial and growth characteristics of S. veridans? Where is it normally found?
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*G+ coccus
*a-hemolytic *normal flora of oral cavity |
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What serious condition is S. veridans associated with? How does this happen? What can be done to prevent it?
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*subacute bacterial endocarditis
*bacteria enter bloodstream through a break in gingival mucosa and attach to pre-existing defect on myocardium or valve *biofilm growth is difficult to tx. *antibiotic prophylaxis before dental tx for pts with pre-existing heart problems |
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What are the bacterial and culture growth characteristics of S. pneumoniae?
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*G+ diplococci
*a-hemolytic *sensitive to optochin (P disk) |
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What are four disease states attributable to S. pneumoniae?
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1.bacterial pneumonia
2.otitis media 3.pneumococcal meningitis 4.bacteremia |
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How is S. pneumoniae spread?
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*p-p via aerosolized droplets
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What predisposes a person to infection with S. pneumoniae?
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Viral infection
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What are 3 virulence factors of S. pneumoniae? What does each do?
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1.Capsule - antiphagocytic
2.Peptidoglycan - proinflammatory 3.Pneumolysin - lyses RBC |
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How can S. pneumoniae be prevented?
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Two vaccines:
*adult: polysaccharide against 23 strains *peds: conjugate against 7 strains |
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What are the bacterial and culture growth characteristics of Enterococcus? Where can it normally be found?
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*G+ cocci
*g-hemolytic *able to grow in harsh conditions including bile *normal flora of GI and GU tracts |
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T/F:
Enterococcus presents most often as a community-acquired infection. |
False: Enterococcus is a major nosocomial infection and rarely presents as being community-acquired.
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What are 3 disease states caused by enterococcus?
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1.Subacute bacterial endocarditis
2.UTI, esp. catheter-related 3.bacteremia |
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What is the recommended treatment for Group D streptococcus? What kinds of resistance problems are associated with this organism?
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*synergistic PCN + aminoglycoside
*multi-rx resistance, esp. VRE |
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What are the bacterial and culture growth characteristics of GBS?
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*G+ coccus
*B-hemolytic *cAMP+ |
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What are three disease states associated with GBS?
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*neonatal sepsis and meningitis
*post partum sepsis *asymptomatic carrier |
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What 3 patient populations are most at risk for infection with GBS?
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*pregnant women
*neonates *DM |
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What are 2 virulence factors associated with GBS?
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*anti-phagocytic capsule
*C5a peptidase |
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Name 3 difficulties in creating a vaccine for S. pyogenes.
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1.Antigenic variation of M protein
2.Cross-reactivity of M protein 3.Many M protein serotypes |
