PBL: Blood Cultures Flashcards

1
Q

Presence of bacteria in the blood

A

Bacteremia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Bacteria passing through (dental, colonoscopy)

A

Transient bacteremia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Bacteria seeding from the infected site to another area intermittently (seeding blood); same organisms on and off

A

Intermittent bacteremia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Bacterial coming from an intravascular source all of the time (endocarditis)

A

Continuous bacteremia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Sepsis going on inside a site such as an IV catheter or endocarditis

A

Primary sepsis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Sepsis going on in an external site such as strep from lungs, UTI, dental surgery, tooth accesses

A

Secondary sepsis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

A contaminant in the blood

A

Pseudobacteremia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Bacteremia w/ organisms multiplying in blood and symptoms showing

A

Septicemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Molds and yeast in the blood

A

Fungemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Viruses in the blood

A

Viremia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Systemic inflammatory response syndrome (things must fall in a category?)

A

SIRS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Inflammation of the cardiac lining

A

Endocarditis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Sepsis w/ hypotension

A

Septic shock

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

When the proteins that control blood clotting become overactive and you get massive bleeding out

A

Disseminated intravascular coagulation (DIC)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Blood culture system where the instrument checks for positive cultures (24/7)

A

Continuous monitoring blood culture systems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Bacteria secreting ____ are notorious for septic shock

A

Endotoxins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Common symptoms and abnormal lab tests that would be associated w/ possible sepsis

A
  • Fever (↑ or ↓)
  • Shaking
  • Chills
  • Tachypnea
  • Prostration (laying down)
  • Blood pressure (↑ or ↓)
  • DIC
  • WBC count (↑ or ↓)
  • Lactic acidosis
  • C-RP (↑)
  • Procalcitonin (indicator of inflammation on high levels indicative of septicemia)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Proper method of collecting a blood specimen for bateriologic culture (5 steps)

A
  1. Alcohol
  2. Iodine based
  3. Make circles going out
  4. Draw opposite arm that has IV
  5. Draw below IV if have to draw from arm w/ IV
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Correlate the number, timing, and volume of specimens w/ optimal recovery of organisms fro meaningful clinical use

A
  • Number: 1 set = 1 aerobic bottle and 1 anaerobic bottle; no more than 3 sets in 24 hours
  • Volume: 8-10mL for adults; 1-3mL for babies
  • Timing: take blood before antibiotics or any therapy and right before a fever
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Blood to medium ratio when collecting a blood culture

A

1:5 to 1:10

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

IV catheter related

A
  • CoNS
  • S. aureus
  • Enterococcus spp.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

UTI

A

Escherichia coli (coming from GI)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Subacute endocarditis

A
  • CoNS

- Streptococcus viridans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Acute endocarditis

A
  • Staphylococcus aureus

- Streptococcus pneumoniae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Oral surgery/dental procedures

A

Mouth flora

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Most comon contaminants found in blood cultures

A

Skin flora

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Immunocompromised

A
  • Anything really

- Fungi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Preexisting pneumonia is the most common cause of septicemia. This pneumonia is caused by…

A
  • Streptococcus pneumoniae

- Klebsiella pneumoniae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the purpose of the BACTEC system?

A

Measuring CO2 by fluorescence

  • Non-radiolabeled CO2 is taken into the sensor, where it reacts w/ dye and produces hydrogen ions
  • ↑ in H+ → ↑ fluorescent light to be detected by the detector
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the purpose of the BacT/Alert system?

A

Measuring CO2 by pH change, changing the color of the sensor from gray to yellow

31
Q

What is the purpose of the SeptiCheck?

A

Agar paddle or slant used to subculture a specimen and you inoculate it by inverting the broth to cover the agar

32
Q

What is the purpose of the Lysis centrifugation?

A

System requires the addition of lysis fluid to blood samples followed by several inversions for mixing. Sediment after centrifugation is used to inoculate all media plates.
- This is for: intracellular pathogens and fungi, yeasts, and molds

33
Q

What is the purpose of sodium polyanetholsulfoante (SPS)?

A

Anticoagulant that inhibits lysozyme neutralization, phagocytosis, and complement that would otherwise kill the bacteria

34
Q

What is the purpose of resins (ARD: antimicrobial removal devices) in blood cultures systems?

A

Neutralizes antibiotics to prevent the killing of bacteria in the sample

35
Q

Proper blood culture procedure for possible brucellosis

A

Castanata bottle/biphasic bottle: used when it takes a long time to grow brucellosis (4 weeks)

36
Q

What approaches could be used to determine whether an isolate is a skin contaminant or a pathogen

A

Collect multiple specimens (3 sets a day max)

- All positive blood cultures more likely to be a pathogen

37
Q

What one Gram POSITIVE organisms may be observed on a gram stained smear from a blood culture bottle but would NOT grow on SBA and, w/ some organisms, not on CHOC

A
  • Anaerobes

- Streptococcus abiotrophia (nutrient variant)

38
Q

What one Gram NEGATIVE organism may be observed on a gram stained smear from a blood culture bottle but would NOT grow on SBA and, with some organisms, not on CHOC

A
  • Haemophilus (only grows on CHOC)
  • Capylobacter (charcoal containing media, not blood OR chocolate)
  • Anaerobes
39
Q

What media should be set up on a positive blood culture, based on results of a positive smear

A
  • SBAP
  • CHOC
  • ABAP
  • Do preliminary susceptibilities
  • – Do GLC for anaerobes
40
Q

What test should you set up if you think you have strep? Of these which can you set up directly from the blood?

A
  • Catalase
  • NaCl
  • PYR
  • Bile Esculin
  • CAMP
  • Optochin (bile solubility)
  • Bacitracin
    Set up from blood: Bile Esculin and optochin
41
Q

If you have a GPC, what should you do first?

A
  • Gram stain
  • Plate it out
  • Optochin right away
42
Q

What would you do if your gram stain was clumped (staph)?

A

Do a coag right away (in 4 hours) FROM BLOOD

43
Q

What would you do if your gram stain was a GNR?

A

Vitek or KIA FROM BLOOD

44
Q

How long do we keep bottles?

A

5 days

45
Q

What is the significance if positive on the first day vs. the fifth day

A
  • First day: more likely to be significant

- Fifth day: more likely to be a contaminant

46
Q

What is teh best way to do a gram stain on a blod?

A

MeOH fixation b/c it preserves red cells the best

47
Q

What is the advantage of the lysis centrifugation system?

A

The sediment (bacteria) is able to be plated immediately after the centrifugation and pressing process has been completed

48
Q

What does PNA FISH stand for?

A

Fluorescence In SItu Hybridization using Peptide Nucleic Acid Probes

49
Q

Principle of PNA FISH

A

Molecular method that uses fluorescent probes to evaluate genes and DNA sequences on a c’some

50
Q

Principle of Verigene

A

Molecular method that rapidly identifies GP organisms

51
Q

Principle of MALDI-TOF

A

Mass spectrometry that rapidly identifies microorganisms and bacteria

52
Q

What does MALDI-TOF stand for?

A

Matrix-Assisted Laser Desportion Ionization Time-Of-Flight

53
Q

Principle of Gene Xpert

A

Rapid molecular test for MRSA

54
Q

What steps should be taken after the Bactec indicates a blood culture bottle is positive?

A
  1. Remove the bottle from the Bactec (only remove the ones marked by the instrument)
  2. Prepare a Gram stain
    2a. Wipe septum w/ 70% isopropyl alcohol, allow to dry, insert syringe into vial and remove medium, make thin prep smear on slide and fix w/ heat or MeOH, then stain
  3. Call doctor and notify them of type of organism(s) noted during gram stain evaluation.
55
Q

Advantages of MeOH fixation

A

Help prevents liquid specimens, such as blood, from washing off the slide; preserves cell morphology, and results in an overall background w/ less debris

56
Q

Disadvantages of heat fixation

A

Runs risk of overheating the slide, therefore causing morphologic changes to the cells

57
Q

What biochemical tests and media should be set up for GPC in clusters?

A
  • Biochemicals: Tube coagulase, QuickFISH

- Media: BAP, CHOC, ANA BAP

58
Q

What biochemical tests and media should be set up for GPC in pairs and/or chains?

A
  • Biochemicals: optochin disk

- Media: BAP, CHOC, ANA BAP

59
Q

What biochemical tests and media should be set up for GNR?

A
  • Biochemicals: Vitek GNI, 73 cards from pellet (new card should be set up every 2 days)
  • Media: BAP, CHOC, ANA BAP, MAC, CNA
60
Q

What biochemical tests and media should be set up for GNC?

A
  • Biochemicals: None

- Media: BAP, CHOC, ANA BAP, ML

61
Q

What biochemical tests and media should be set up for GNR?

A
  • Biochemicals: None

- Media: ALL get BAP, CHOC, and ANA BAP (Lactobacillus: add TJ; Bacillus spp: add PEA)

62
Q

What biochemical tests and media should be set up for yeast (yeast-like fungi)?

A
  • Biochemicals:yesat traffic light PNA FISH (every 14 days)

- Media: BAP, CHOC, ANA BPA, CSAB, CAC

63
Q

Incubate ____ media for 48 hours in ____ @ 35°C

A

Aerobic; CO2`

64
Q

Incubate TJ and ANA BAP in ____ conditions for 48 hours @ 35°C

A

Anaerobic

65
Q

Normal skin flora

A
  • Alpha/gamma streptococci (Streptococcus viridans) → GPCs
  • Corynebacterium spp (“dipthroids”)
  • CoNS → GPC
  • Propionibacterium spp (P. acnes) → GPR
  • Staphylococcus saccharolyticus → GPC
66
Q
Intraabdominal infections (perforated GI → abscess)
- What is the cause of primary peritonitis?
A

Cirrhosis

67
Q
Intraabdominal infections (perforated GI → abscess)
- What bacteria cause secondary peritonitis?
A
  • E. coli → GNR
  • Anaerobes
  • Enterococcus spp → GPC
68
Q

Normal GI flora

A
  • Anaerobes (Bacteroides fragilis group, Clostridium spp., Bifidobacterium spp., anaerobic cocci, Fusobacterium spp)
  • E. coli → GNR
  • Enterobacteriaceae → GNR
  • Enterococcus spp → GPC
69
Q

Colon cancer

A
  • Clostridium septicum → GPR

- Streptococcus bovis → GPC

70
Q

Normal mouth flora

A
  • Alpha/gamma Streptococci → GPC
  • Corynebacterium → GPR
  • CoNS → GPC
  • Non-pathogenic Neisseria spp → GN diplococci
  • Prevotella melaninogenica → GNR
  • Porphyromonas spp → GNR
  • Prevotella spp → GNR
71
Q

Skin infections

A
  • Staphylococcus aureus → GPC
  • Group A Strep (Streptococcus pyogenes) → GPC
  • Group B Strep (Streptococcus agalacticae) → GPC
72
Q

Brucella spp

- Gram stain

A

Small GNCB

73
Q

Brucella spp

- Blood culture collection

A
  • Collected as ordinary blood cultures but incubated in BacTec FX for 14 days
  • Vial will be cultured in TSA weekly, and plates will be sotred in CO2 incubator for 4 days
74
Q

Brucella spp

- Isolator tube collection

A

Will be plated on BAP, CHOC, and TSA and incubated for 14 days