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59 Cards in this Set
- Front
- Back
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Hemolysis of RBCs by Alpha, Beta, Gamma hemolytic strep?
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Alpha -partial
Beta - complete Gamma - non-hemolytic |
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Hemolysis of Strep pyogenes, Strep pneumoniae, Strep agalactiae,
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Strep Pyogenes - Beta
Strep pneumo - Alpha Strep agalactiae - Beta |
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What is the significance of M protein?
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Inhibits activation of complement and protects organism from phagocytosis
Plasma cells generate antibodies to M protein |
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What are the virulence factors of Strep Pyogenes?
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M protein
Streptolysin O Streptolysin S Pyrogenic exotoxin Streptokinase Hyaluronidase DNAases Anti-C5a peptidase |
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What is the significance of Streptolysin S?
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Responsible for Beta Hemolysis
Not antigenic |
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What is the significance of Pyrogenic exotoxin?
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Scarlet fever causing toxin
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What diseases can GAS cause by local invasion or exotoxin release?
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Streptococcal pharyngitis
Streptococcal skin infections Scarlet fever Streptococcal toxic shock syndrome |
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What diseases can GAS cause by delayed antibody mediated diseases?
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Rheumatic fever
Glomerulonephritis |
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What is antibiotic treatment for GAS necrotizing fasciitis?
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Penicillin G and Clindamycin (inhibits metabolism and will block toxin production)
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Which bugs cause necrotizing fasciitis?
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GAS
Staph Clostridium Gram negative enterics Mixed infection with these |
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What is the significance of Streptolysin O?
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Oxygen labile
Enzyme destroys red and white blood cells Antigenic (ASO antibodies) |
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What toxin is responsible for scarlet fever?
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Pyrogenic toxin (erythrogenic toxin)
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How does scarlet fever rash spread?
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Starts on truck and neck and spreads to extremities
Spares face |
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Antibiotic treatment for Streptococcal toxic shock syndrome?
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Penicillin G and Clindamycin (inhibits toxin production, metabolism)
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Prophylactic treatment for patients with Rheumatic Fever?
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Penicillin for much of the patient's life to prevent future GAS infections. Dental and surgical amoxicillin prophylaxis for valvular complications.
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After which sorts of infections does glomerulonephritis from GAS occur?
How long after this infection? |
Skin or Pharynx
1 week |
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What sort of hemolysis do GBS have?
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Beta hemolysis
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What sort of disease do GBS cause?
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Meningitis
Pneumonia Sepsis |
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What sort of hemolysis do viridians group strep have?
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Alpha hemolysis
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What are the three main sorts of infections in which viridians group strep are implicated?
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Abscess
Endocarditis Dental |
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What sort of viridians group strep causes abscesses?
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Strep intermedius group (Strep intermedius, Strep constellatus, Strep anginosus)
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What should be done in case of a strep intermedius growing blood culture?
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CAT scan for abscess
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What type of hemolysis do group D strep have?
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Alpha hemolysis
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What are the two subgroups of group D strep and what are their members?
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Enterococci - Enterococcus faecalis, enterococcus faecium
Non-enterococci - Strep bovis, Strep equinus |
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What sort of infections are caused by enterococci?
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UTI
SBE Biliary tract infections Bacteremia |
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What tests allow for identification of pneumococcus?
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Quellung reaction - mix slide with samll amount of antiserum and methylene blue, capsule swells
Optochin sensitivity - separate from strep viridans (alpha hemolytic) by placing disc of optochin in culture (inhibits pneumococcus, not viridans) |
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What sort of hemolysis does pneumococcus have?
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Alpha hemolysis
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How many species of pathogenic staph are there are what differentiates staph aureus from the other two?
What are the other species? |
Three
S. aureus is coagulase positive S. epidermidis S. saprophyticus |
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What does Staph Aureus protein A do?
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Binds to Fc portion of IgG to protect from opsonization and phagocytosis
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What does Staph Aureus coagulase do?
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Fibrin formation around bacteria protecting it from phagocytosis
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Staph aureus virulence factors (immune, antibiotic)?
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Protein A
Coagulase Hemolysins Leukocidins Penicillinase Novel penicillin binding protein |
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Staph aureus virulence factors (tunneling)?
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Hyaluronidase
Staphylokinase Lipase Protease |
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Staph aureus exotoxins?
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Exfoliatin
Enterotoxin (heat stable - food poisoning) Toxic Shock syndrome Toxin |
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How many cultures must grow Staph epi for probability of staph epi sepsis to be high enough to warrant treatment?
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2
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Most common infection caused by staph saprophyticus?
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UTI
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Contact with what materials tends to be associated with anthrax infection in US?
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Products with goat hair from Haiti (i.e. drums, rugs)
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Most common type of anthrax infection?
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Cutaneous
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Appearance of cutaneous anthrax?
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Round black lesion, painless, rim of edema
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Mechanism of disease in GI anthrax?
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Maturation and replication in intestine where it releases exotoxin causing necrotic lesion.
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Three protein components of anthrax GI exotoxin?
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Edema factor
Protective antigen Lethal factor |
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Drugs used in anthrax infection?
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Penicillin
Doxy Cipro Levofloxacin |
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What composes anthrax vaccine (for humans)?
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Protective antigen
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What sorts of exotoxins are released by B. cereus?
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Heat labile toxin - similar to E. Coli toxin
Heat stable toxin - syndrome similar to S. aureus food poisoning |
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Sequence of signs of adult botulinum toxicity?
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Bilateral cranial nerve palsies
Generalized muscle weakness Respiratory paralysis |
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Treatment of adult botulinum toxicity?
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Antitoxin - binds free toxin in serum
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Signs of infant botulism?
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Constipation for 2-3 days
Difficulty swallowing, muscle weakness |
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Treatment of infant botulinum toxicity?
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Supportive care, prognosis is good so no antitoxin
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Mechanism of action of tetanus toxin?
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Inhibits GABA release from inhibitory Renshaw cell interneurons
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Treatment of people who had tetanus immunization greater than 10 years previously?
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Booster shot
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Treatment of people never immunized for tetanus?
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Booster + Immunoglobulin
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Treatment of people who have developed tetanus?
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Immunoglobulin
Booster Clean wound Penicillin |
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Types of C. perfringens infection?
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Cellulitis, wound infection
Clostridial myoinfection |
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Treatment of C. perfringens myonecrosis?
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Hyperbaric oxygen
Antibiotics Removal of tissue |
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What are C. Difficile exotoxins and their mechanisms?
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Toxin A - diarrhea
Toxin B - toxic to colonic epithelium |
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Diagnosis of C. Difficile?
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Toxin in stool
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What sort of media does diphteriae culture on?
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Potassium tellurite agar
Loeffler's coagulated blood serum media |
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Treatment of Diphtheria?
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Antitoxin - inactivates circulating toxin
Penicilllin or erythromycin DPT vaccine |
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Components of the Diphtheria toxin and functions?
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B subunit binds to target cell
A subunit enters cell and blocks protein synthesis by inactivating elongation factor |
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Which antibiotics are used to cover Listeria?
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Ampicillin or TMP-SMX
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