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37 Cards in this Set
- Front
- Back
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What are 2 characteristics of Bacteremia?
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-Transient
-Secondary to infection elsewhere. |
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What are 2 characteristics of Septicemia?
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-Bloodstream infection
-Usually systemic spread of GNB. |
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What are the 2 types of Endocarditis?
What is the difference? |
Subacute: less severe, caused by valve damage.
Acute: more severe, caused by primary infection. |
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What are the top two causes of bloodstream infections?
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1. Coag neg staphs
2. Enterococcus (check on this though) |
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How do Iv catheters cause BSIs?
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-By causing biofilms
-NF on skin enters puncture site. |
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How are catheter-induced BSIs processed?
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1. Cut off 2" of IV/catheter
2. Roll across BA w/ sterile forceps |
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How is a catheter roll interpreted?
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If 15 or more colonies grew, indicates infection.
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What timeframe should blood be collected in for:
-Bacteremia? -Septicemia? |
Septic - doesn't matter.
Bacteremia - 30-45 min before fever spike. |
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What variables should be controlled during blood collection?
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1. Skin antisepsis/venipuncture
2. Blood volume required 3. Number of draws/timing 4. NEVER draw from IV. |
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How many draws are optimal?
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3 - 99% recovery
2 - 90% 1 - 80% |
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How soon before one arm can have another sample drawn?
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45 minutes
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What is the best wipe to use for cleaning the draw site?
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Tincture of iodine
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Describe the skin antisepsis prep:
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1. Use alcohol wipe/iodine tinct
2. wipe 30-60 seconds 3. Wait 30 sec before puncture |
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What are the requirements re: blood volume for drawing?
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Blood:diluent should be 1:10
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How many mls per draw is optimal?
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At least 20 mL
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What should be done, whatever culture media is used for blood?
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Vent at least one bottle for aerobic bugs.
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What additive is used for blood cultures? What is its purpose?
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SPS - anti coagulant to prevent clot from trapping bugs.
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What bug resists SPS?
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Peptostreptococcus
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How long should blood cultures be incubated? At what temp?
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Keep 5-7 days
37 'C |
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What are 4 Non-automated methods for blood cultures?
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1. Manually observe the bottles
2. ISolator 3. Septi-Chek 4. Signal |
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How does the Isolator work?
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-It spins the blood to concentrate bugs, then you inoculate the plate.
-Adds lysing reagent to free bugs from host cells. |
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How does the septi-chek work?
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It has solid media in neck of tube, over broth. You invert everyday.
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How does the Signal system work?
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It detects CO2 released as bacteria grow. Forces gas into upper chamber above media.
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What are the automated blood culture systems NOT for?
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Identification; only detection.
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What are the 4 principles of automated systems?
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1. Fluorescence detection
2. Laser detection 3. Colorimetric CO2 detection 4. Headspace pressure change detection |
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-What's the principle of the Fluorescence detection?
-What's an example? |
-Matrix at bottom of tube lets H+ ions release, changes fluorescence.
-Detector is against matrix. |
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-What's an example of the fluorescence detection?
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Bactec 9000
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What is a laser detection system?
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Bactec LX
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How does the laser detection work?
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Growth of bacteria causes CO2 diffusion; Fluorescence changes; Laser passes through bottle neck and detects change.
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How does the Colorimetric CO2 detection work?
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Acidic CO2 causes a pH change in the environment, An indicator in matrix changes color.
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What is an example of colorimetric detection?
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BacT/Alert
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What's another name for headspace pressue change detection? What does it work for?
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-ESP
-Works for ANY gas, not only CO2 -Decreases when bug USES O2 -Increases when bug produces gas. |
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How are positive blood cultures PROCESSED?
-Stains -Procedures -Inoculation |
-Stain with 1)GRAM 2)ACRIDINE Orange
-Contact DOctor IMmediately!!! -Culture to BA/Chocolate, if GNB do Lemb/MAC |
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What is the ACCEPTABLE CONTAMINATION RATE for blood cultures?
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Less than 3%
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What are some causes of blood culture contamination?
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-Poorly trained phlebotomist
-Not drawing directly into tubes -Poor skin prep -Touched the site of puncture -Drawing from the IV TUBE! :( Bad contamination tracking |
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What are 4 indicators of bacterial contamination?
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1. Only one bottle/3 is positive
2. Patient's WBC cnt is normal 3. 2/more organisms grow 4. Growth is slow to emerge. |
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How should a possibly contaminated transfusion blood bag be worked up?
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1. Process as a blood culture
2. Inoculate 2 bottles -25'C for psychrophiles -37'C for mesophiles 3. Save bag/tube till done. |
