strep, enterococ Flashcards

Strep pneumoniae
Terms Definitions
gram stain of strep/entero generi (two genera)
NOT nice and round; broth cultures give chains in gram stain.a little messier than staphs
What are the growth characteristics of Streptococcus and Enterococcus?
Fastidious, facultative anaerobes (like Staphs, only fastidious)Grows on BA in increased CO2
What are the characteristic antigens on Streptococcus species?
C carbohydrates - use lancefield typingM protein - protects from phagocytosis
3 Ways Streps and Enterococcus are differentiated:
1. Hemolysis2. Presumptive tests - biochemical3. Definitive tests - imunological
gamma isolates of strep/enter
S. viridansEnterococcusStrep group D Non-Enterococcus
two tests on gamma isolates
-bile esculin (neg shows saprophyticus)-6.5% NaCl (pos shows enterococ, neg shows strep D non-enter)
What test is an alternate to 6.5% NaCl?
PYR HYDROLYSIS
Where is S. viridans normal flora?
mouth/vagina
What causes Bacterial Endocarditis?-Acute-Subacute
Subacute caused by:-Staphylococcus epidermidis-Streptococcus viridansAcute caused by:Staphylococcus aureus
What is used to treat Streptococcus viridans infections?
penicillin
what is intrinsiclaly resistant to penicillin
enterococcus; not due to beta lactamase, it just is
4 diseases caused by enterococci
bacteremiaendocarditiswound infectionsUTI
treat with __ if an enterococcus is -blactamase neg-b-lactamase pos
neg = ampicillinpos = vancomycin
VRE(2 genes that encode it)
vancomycin resistant enterocVanAVanB
how do Van A and Van B mediate resistnc?
A - plasmid-mediated; worse cuz it can jump to other bugsB - chromosomally-mediated; stays within the cell line.
know about Strep D non-enteroc:
rare in humans, can cause endocarditis, treat w/ penicillin
You have an alpha-hemolytic gram positive cocci; what tests do you inoculate?
1. bile esculin2. salt3. optichin
principle of optichin test
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)
alpha hemolytic, bile esculin negative, optichin positive/negative: que es?
s. pneumoniae is posS. viridans is neg
what tests is alternate to optichin?
bile solubility
micro/macro morpho of strep pneumoniae
1. lancet shaped GPDC2. if autolyzed, flat, mucoidy, checkersMAKES A CAPSULE
What makes Strep pneumoniae pathogenic?
-capsule-M-protein which makes it resist phagocytosis
lobar pneumonia pathology: what happens?
bug enters, inflammatory response is WBC, fluid and RBC; can't breathe across alveoli - lobar consolidation
high fever; shaking chills; sharp pleural pain; rusty sputum; what is it?
lobar pneumoniae caused by strep pneum.
why does s. pneumon cause red sputum?
rbc's in it
3 diseases caused by strep pneumoniae:
lobar pneumoniameningitisotitis media
to treat s. pneumonia:
=penicillin or ciprofloxacinvancomycin if necess
normal flora site of strep pneumoniae
oral cavity, small numbers
enterococcus normal flora site
intestine
how do you prevent streptococcal pneumoniae?
via vaccine;pneumovax for over 2 years old, PREVNAR FOR under 2
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
tests done on beta strep
bile esculinbacitracin or pyrCAMP or hipp hydrolysis
bile esculin of beta strep diffs
positive is rare - nothingnegative do tests on
test to do on bile esc negative organisms:
CAMP - identifies beta strep BBacitracin - identifies beta strep A
does beta strep A resist or suscept to bacitracin?
it's positive, so it resists it
principle of CAMP test
beta strep B produce compound that in conjunction with S. Aureus' hemolysin will cause complete hemolysis and an arrow shape
alternate test for CAMP
hippurate
Beta strep Antigen akahow to test for it
C- carbohydrateflourescent antibody or latex agglutination
strep group A aka and its normal flora site:
aka strep pyogenes; normally in oral cavity in 15% of population
s. pyogenes produces what 6 pathogenic products:
streptokinase - digest fibrin, spreadstreptodornase - break down dnahylauronidase - break down connect tisserythrogenic toxin - red scarlet feverhemolysins - break down RBCM protein - resist phagocytosis
two hemolysins produced by s. pyogenes, strep group A:
Streptolysin S, OASO TEST tests for O by antibody actionO is O2 labileS is O2 stabile
diseases caused by strep pyogenes (A)
strep throatscarlet fevererysipelas and cellulitisimpetigowound infectionspyogenic STrep A infectionspost-strep diseases
what are pyogenic strep A infections?
necrotizing fasciitistoxic shoc-LIKE SYNDROME
what are post streptococcal diseases?
acute glomerulonephritisrheumatic fever
how do you treat strep pyogenes (group a)
with peniccilin
strep group B is aka normal floral site?
strep agalactiaenormally in oral cavity in low numbers, maybe vagina but abnormal and must protect fetus before delivery
what type of infection does s. agalactiae cause
neonatal infections:-meningitis/sepsis-respiratory distress syndrome-osteomyelitis
direct specimen test for S. agalactiae
group b Antigen test
how do you treat group B strep? (s. agalactiae)
with penicillin
beta hemolytic strep other than A B or D
normal flora, COULD cause phjaryngitis (streplike) but normal usually, susceptible to peniccilin
what are 5 OTHER cat neg GPC?
=leukonostoc - rare, unusual to cause infection, only in compromised; INTRINSIC RESISTANCE TO VANCOMYCIN!-aerococcus-gemella-pediococcus-lactococcus
What are all streptococcus organisms treated with, and what is NOT treated with it?
Enterococcus is intrinsically resistant, but everything else is susceptible to penicillin.
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