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52 Cards in this Set
- Front
- Back
gram stain of strep/entero generi (two genera)
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NOT nice and round;
broth cultures give chains in gram stain. a little messier than staphs |
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What are the growth characteristics of Streptococcus and Enterococcus?
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Fastidious, facultative anaerobes (like Staphs, only fastidious)
Grows on BA in increased CO2 |
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What are the characteristic antigens on Streptococcus species?
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C carbohydrates - use lancefield typing
M protein - protects from phagocytosis |
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3 Ways Streps and Enterococcus are differentiated:
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1. Hemolysis
2. Presumptive tests - biochemical 3. Definitive tests - imunological |
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gamma isolates of strep/enter
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S. viridans
Enterococcus Strep group D Non-Enterococcus |
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two tests on gamma isolates
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-bile esculin (neg shows saprophyticus)
-6.5% NaCl (pos shows enterococ, neg shows strep D non-enter) |
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What test is an alternate to 6.5% NaCl?
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PYR HYDROLYSIS
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Where is S. viridans normal flora?
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mouth/vagina
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What causes Bacterial Endocarditis?
-Acute -Subacute |
Subacute caused by:
-Staphylococcus epidermidis -Streptococcus viridans Acute caused by: Staphylococcus aureus |
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What is used to treat Streptococcus viridans infections?
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penicillin
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what is intrinsiclaly resistant to penicillin
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enterococcus; not due to beta lactamase, it just is
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4 diseases caused by enterococci
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bacteremia
endocarditis wound infections UTI |
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treat with __ if an enterococcus is
-blactamase neg -b-lactamase pos |
neg = ampicillin
pos = vancomycin |
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VRE
(2 genes that encode it) |
vancomycin resistant enteroc
VanA VanB |
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how do Van A and Van B mediate resistnc?
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A - plasmid-mediated; worse cuz it can jump to other bugs
B - chromosomally-mediated; stays within the cell line. |
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know about Strep D non-enteroc:
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rare in humans, can cause endocarditis, treat w/ penicillin
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You have an alpha-hemolytic gram positive cocci; what tests do you inoculate?
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1. bile esculin
2. salt 3. optichin |
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principle of optichin test
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disc contains ethylhydrocupreine HCl; if the bug is susceptible, zone of more or equal to 14 mm will show. resistant if less. (S. pneumonia and S. viridans are resistant)
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alpha hemolytic, bile esculin negative, optichin positive/negative: que es?
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s. pneumoniae is pos
S. viridans is neg |
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what tests is alternate to optichin?
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bile solubility
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micro/macro morpho of strep pneumoniae
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1. lancet shaped GPDC
2. if autolyzed, flat, mucoidy, checkers MAKES A CAPSULE |
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What makes Strep pneumoniae pathogenic?
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-capsule
-M-protein which makes it resist phagocytosis |
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lobar pneumonia pathology: what happens?
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bug enters, inflammatory response is WBC, fluid and RBC; can't breathe across alveoli - lobar consolidation
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high fever; shaking chills; sharp pleural pain; rusty sputum; what is it?
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lobar pneumoniae caused by strep pneum.
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why does s. pneumon cause red sputum?
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rbc's in it
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3 diseases caused by strep pneumoniae:
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lobar pneumonia
meningitis otitis media |
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to treat s. pneumonia:
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=penicillin or ciprofloxacin
vancomycin if necess |
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normal flora site of strep pneumoniae
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oral cavity, small numbers
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enterococcus normal flora site
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intestine
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how do you prevent streptococcal pneumoniae?
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via vaccine;
pneumovax for over 2 years old, PREVNAR FOR under 2 |
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What test identifies S. viridans?
2 species and commonly caused disease (Kristine) |
Optichin neg (diff from s. pneumoniae)
S. MUTANS AND S. SANGUIR ASSOC. W/ DENTAL CARIES |
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tests done on beta strep
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bile esculin
bacitracin or pyr CAMP or hipp hydrolysis |
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bile esculin of beta strep diffs
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positive is rare - nothing
negative do tests on |
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test to do on bile esc negative organisms:
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CAMP - identifies beta strep B
Bacitracin - identifies beta strep A |
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does beta strep A resist or suscept to bacitracin?
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it's positive, so it resists it
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principle of CAMP test
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beta strep B produce compound that in conjunction with S. Aureus' hemolysin will cause complete hemolysis and an arrow shape
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alternate test for CAMP
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hippurate
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Beta strep Antigen aka
how to test for it |
C- carbohydrate
flourescent antibody or latex agglutination |
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strep group A aka and its normal flora site:
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aka strep pyogenes; normally in oral cavity in 15% of population
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s. pyogenes produces what 6 pathogenic products:
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streptokinase - digest fibrin, spread
streptodornase - break down dna hylauronidase - break down connect tiss erythrogenic toxin - red scarlet fever hemolysins - break down RBC M protein - resist phagocytosis |
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two hemolysins produced by s. pyogenes, strep group A:
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Streptolysin S, O
ASO TEST tests for O by antibody action O is O2 labile S is O2 stabile |
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diseases caused by strep pyogenes (A)
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strep throat
scarlet fever erysipelas and cellulitis impetigo wound infections pyogenic STrep A infections post-strep diseases |
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what are pyogenic strep A infections?
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necrotizing fasciitis
toxic shoc-LIKE SYNDROME |
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what are post streptococcal diseases?
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acute glomerulonephritis
rheumatic fever |
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how do you treat strep pyogenes (group a)
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with peniccilin
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strep group B is aka
normal floral site? |
strep agalactiae
normally in oral cavity in low numbers, maybe vagina but abnormal and must protect fetus before delivery |
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what type of infection does s. agalactiae cause
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neonatal infections:
-meningitis/sepsis -respiratory distress syndrome -osteomyelitis |
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direct specimen test for S. agalactiae
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group b Antigen test
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how do you treat group B strep? (s. agalactiae)
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with penicillin
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beta hemolytic strep other than A B or D
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normal flora, COULD cause phjaryngitis (streplike) but normal usually, susceptible to peniccilin
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what are 5 OTHER cat neg GPC?
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=leukonostoc - rare, unusual to cause infection, only in compromised; INTRINSIC RESISTANCE TO VANCOMYCIN!
-aerococcus -gemella -pediococcus -lactococcus |
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What are all streptococcus organisms treated with, and what is NOT treated with it?
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Enterococcus is intrinsically resistant, but everything else is susceptible to penicillin.
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