-
this is the invasion of bloodstream by virulent microorganisms.
septicemia
-
this is the transient presence of bacteria or other microorganisms in the blood.
bacteremia
-
this is the presence of fungi in the blood stream.
fungemia
-
this is the presence of viruses in the blood, characterized by malaise, fever, and aching of the back and extremities
viremia
-
septic shock is caused by what?
the release of toxins
-
what are five signs and symptoms of spetic shock?
- fever
- respiratory distress
- I.V. coagulation
- Renal failure
- tissue damage
-
this is one of the most important specimens.
blood culture
-
healthy individuals have _______ blood.
sterile
-
what is the objective of blood cultures?
initiate growth of tastidious organisms
-
this involves very small numbers of organisms.
bacteremia
-
is septicemia more common in adults or infants?
infants
-
this may depend on prompt recognition by bacteriologic means.
prognosis
-
true or false
positive blood cultures reflect a variety of conditions and diseases
true
-
bacteremia is __________ in endocarditis, concontrolled infections, typhoid fever, and brucellosis.
continuous
-
in the early antibiotic era the primary concern was spesis due to what?
staphylococcus aureus
-
recently there is an increase in infections caused by gram negative bacteria such as what?
-
what are the two most frequent isolates from the pediatric population?
- haemophilus influenzae
- streptococcus pneumoniae
-
what is the mortality rate of septicemias?
20-50%
-
this is reported in approximately 18% of proven septicemias, and associated with a higher mortality than unimicrobial infection
polymicrobial bacteremia
-
what three diseases are significant to gram negative septicemia?
- acute fulminating meningoccemia (waterhouse friderichsen syndrome)
- meningococci lipopolysaccharide endotoxin
- coagulation cascade activation (DIC)
-
which gram negative septicemia disorder is seen mainly in children under ten years old?
acute fulminating meningococcemia (waterhouse friderichsen syndrome)
-
what two broths can be used for blood culture media?
-
what amount of CO2 is used in blood culture media?
5-10%
-
this allows the maximal yield of fastidious organisms and dispaces oxygen for anaerobic conditions.
CO2
-
what is the anticoagulant used in blood culture media?
sodium polyanethol sulfonate (SPS)
-
what are three advantages of sodium polyanethol sulfonate as an anticoagulant?
- antiphagocytic
- anti-complementary
- inactivates certain antibiotics (aminoglycosides)
-
what is the disadvantage of sodium polyanethol sulfonate as an anticoagulant?
inhibitory for certain bacterial species
-
what four bacterial species are inhibited by sodium polyanethol sulfonate?
- peptostreptococcus anaerobius
- gardnerella vaginalis
- some neisseria strains
- S. monliformis
-
how is the inibitory action of SPS neutralized?
1.2% gelatin
-
why is citrate and oxalate not used as an anticoagulant in blood cultures?
toxic for many organisms (GP)
-
why is heparin not used as an anticoagulant in blood cultures?
inhibtory
-
these help bacterial recovery, couteract nor bactericidal mechanism of blood and causes turbidity.
osmotic stabilizers
-
what are the three osmotic stabilizers in blood cultures?
-
what two things are used in blood cultures to absorb all antibiotics?
-
what is used in blood cultures to inactivate penicillin?
penicillinase
-
what is the purpose of a mycobacterial blood culture?
to detect mycobacterium
-
what are the two components of a mycobacterial blood culture?
- middlebrook 7H9
- automated system (Bactec MGIT)
-
what temperature should blood culture media be stored at?
room temperature
-
scrupulous ____ preperation of venipuncture site is required.
skin
-
antiseptic should remain on the skin for how long?
at least one minute
-
how long should 70% alcohol be applied after palpation of the site?
at least 30 seconds
-
how much blood should be collected for blood culture?
up to 20mL
-
how much blood should be in each culture bottle?
up to 10ml
-
what are four contaminants of blood cultures?
- stphylococcus epidermidis
- propionbacterium acnes
- diphtheroids
- bacillus species
-
how many samples should be collected in 24-48hrs to isolate?
three
-
when should you collect two samples from two sites at the same time?
if a patient is to be given antibiotics
-
______ culture is not enough to eliminate bacteremia
single
-
what is the minimal dilution to unmodified medium for blood culture?
1:5
-
how much blood should be drawn from an infant for blood culture?
- 1-5 ml depending on weight
- up to 4.5% of total blood volume
-
the sterile needle and syringe method is an example of what collection system?
open system collection
-
if using an open system the sample should be injected into culture bottle where?
bedside
-
using two syringes when collecting blood cultures reduces skin ______________.
contamination
-
when blood is taken directly from patient via sterile transfer set directly into bottle it is an example of what system?
closed system
-
how long can blood cultures be refrgerated for before testing?
two hours
-
at what temperature should blood cultures be incubated?
35oC
-
how long should routine aer/ana cultures be incubated for?
5-7days
-
how long should SBE cultures be incubated for?
28 days
-
how long should brucella cultures be incubated for?
21-28 days
-
how long should fungi be incubated for? at what temp?
-
when should macroscopic/radiometric examination be performed?
durring first 6-8 hours then daily
-
what should aerobic cultures be subcultured to?
- Choc 5-105 CO2 for 24-48hrs
- BAP
-
what medias should anaerobic cultures be subcultured to?
shaedler's BAP
-
when do you subcultue a blood culture?
anytime culture turns positve macroscopically
-
what is a self-contained subculture system called?
biphasic
-
what are the six portals of entry and their respective percentages?
- GU tract 25%
- respiratory- 20%
- Abscesses- 10%
- surgical wound- 5%
- misc sites- 10%
- uncertain sites- 25%
-
what are the six commonly isolated GPC's?
- S. epidermidis
- S. aureus
- Enterococcus spp
- strep pneumoniae
- viridans strep
- beta strep
-
what are the six commonly isolated GNR's?
- Enerobacter cloacae
- haemophilus influenzae
- E. coli
- P. aeruginosa
- K. pneumoniae
- proteus spp
-
what is the commonly isolated yeast?
C. albicans
-
what are the two commonly isolated anaerobes?
- B. fragillis
- Clostridium spp.
-
this is a group of fastidious GNR associated with infective endocarditis
HACEK
-
what are the bacteria in the HACEK group?
- H. aphrobilus
- A. actinomycetecomitans
- C. hominis
- E. corrodens
- K. kingae
-
what are four findings on a positive blood culture?
- turbidity on medium
- growth on RBC sediment
- hemolysis
- gas production
-
how long is a stock culture maintained for?
several months
-
in what positive blood culture would you see uniform growth, turbidity or gas bubbles?
GNR's
-
in what positive blood culture would you see no change?
haemophilus
-
in what positive blood culture would you see marked hemolysis, gas, and an unpleasant odor?
clostridium
-
in what positive blood culture would you see turbidity balls and jelly-like coagulum?
S. aureus
-
in what positive blood culture would there be a greenish tint to the medium?
pneumococci
-
in what positive blood culture would there be marked hemolysis?
beta strep
-
in what positive blood culture would there be turbidity, foul odor, and less gas?
bacteroides
-
in what positive blood culture would there be hemolyzed RBC's?
bacillus spp
-
in what positive blood culture would there be a thick pellicle on media surface?
saprophytic fungi
-
when is a blood culture considered negative?
after three to four sets
-
when do you report negative results?
after 7 days
-
what newer system monitors radio-labeled C14?
radiometric (BACTEC) system
-
what newer system monitors pH changes by colorimetric indicator?
BacT/ALERT
-
this newer system puts concentrate onto plate media allowing a faster, better recovery.
lysis centrifugation
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