Unit 1 Flashcards
1
Q
Validity
A
how accurate a test is
2
Q
Reliability
A
how often the expected result shows
3
Q
SOP
A
standard operating procedures
4
Q
Reference organism
A
ATCC strains - behave like an actual specimen in both physical and chemical characteristics, utilized to confirm the validity and reliability of media, reagents and biochemical procedures
5
Q
ATCC
A
American Type Culture Collection
6
Q
Exempt media
A
Certain media will not require user testing, based on CLSI guidelines. Manufacturer certification provided
7
Q
Non-exempt media
A
User-prepared. Keep records of sterility, testing with QC organisms of all new batches
8
Q
Panic values
A
communicated immediately to an authorized clinician and documented. Have read back to you
9
Q
Turnaround time
A
time to complete test from sample arrival to results reported
10
Q
QC
A
Internal activities that ensure diagnostic test accuracy
11
Q
QA
A
external activities that ensure diagnostic test accuracy
12
Q
Patent outcomes
A
reduced length, cost of stay, TAT diagnosis, customer satisfaction
13
Q
Benchmarking
A
compare your labs results to that of your peers
14
Q
Qualitative AST
A
measured by the quality
15
Q
Quantitative AST
A
measured by the quantity
16
Q
MBC
A
Minimum bactericidal concentration
17
Q
SBT
A
Serum Bactericidal Tests
18
Q
Microdilution
A
technique used to measure antibiotic susceptibility in which the drug is diluted in a broth
19
Q
Peak level
A
draw when the dosage is expected to be highest
20
Q
Trough level
A
draw before patient’s next dose
21
Q
Intrinsic resistance
A
results from the normal state of organism
22
Q
Acquired resistance
A
altered physiology and structure changes in organism
23
Q
Mode of Action
A
how an antimicrobial funtions
24
Q
Synergy
A
activity greater than activity of single most active drug
25
Antagonism
activity less than activity of single most active drug
26
Drug of choice
antibiotic treatment that will normally work against organism class
27
McFarland Standard
reference to adjust the turbidity of bacterial suspensions so the number of bacteria will be within a given range to standardize testing
28
Zone of inhibition
area around antimicrobial which is lysed
29
Interpretative categories
Susceptible
Intermediate
Resistant
30
Supplemental tests
additional confirmatory tests
31
Beca lactamase
enzymes that destroy penicillins and/or caphalosporins and are produced by a variety of bacteria
32
Emperic therapy
beginning antibiotic treatment before confirmed test results
33
Bacteriostatic
inhibits but does not kill
| Ex. Chloramphenicol, erythromycin, clindamycin, tetracycline
34
Bacteriocidal
kills the target organism
| Ex. aminoglycosides, beta-lactams, vancomycin, quinolones
35
Susceptible
infection caused by the tested organism may be treated with a recommended dose of antimicrobial
36
Intermediate
isolate may be inhibited by attainable concentrations of certain drugs
37
Resistant
isolates are not inhibited by the concentration of antimicrobial achievable with a recommended dose
38
MIC - Minimal Inhibitory Concentration
quantitative monitoring drug dosage schedules in serum or when diffusion tests are equivocal or impractival
39
MBC testing
Minimal bactericidal concentration (continuation of MIC)
40
How to read and interpret disk diffusion zone sizes
measure lysed area in mm by ruler. Compare to CLSI standards of resistance
41
Reading dilutions to determine MIC value
After plate is incubated the tech checks growth with the control. If a dilution shows the bottom two wells but not the top two then the MIC value is the lowest number you DONT see growth in
42
significance of SBC
Modification of broth dilution method that measures the bactericidal activity from patients serum during therapy against the bacterial pathogen isolated from the patient
43
SBC sample
patient's serum
44
When to perform AST testing
a. Isolate clinical significant?
b. chance of resistance
C. standard methods avaliable
45
Beta Lactam Spectrum
Both
46
Beta Lactam Mode of Action
inhibit cell wall synthesis
47
Beta Lactam Examples
Ampicillin
Piperacillin/Tazobactam
Cephazolin
Imipenem
48
Beta Lactam Bacterio_____
Bacteriocidal
49
Oxazolidinones spectrum
Gram +
50
Oxazolidinones Mode of Action
initiates protein synthesis
51
Oxazolidinones Examples
Linezolid
52
Oxazolidinones Bacterio_____
Bacteriostatic
53
Aminoglycosides Spectrum
Gram + and gram - not anaerobic
54
Aminoglycosides Mode of Action
inhibit protein synthesis
55
Aminoglycosides Examples
Gentamicin
56
Aminoglycosides
| Bacterio_____
Bacteriocidal
57
Glycopeptides Spectrum
Gram + topical
58
Glycopeptides Mode of Action
inhibit bacteria cell wall synthesis
59
Glycopeptides Examples
Vancomycin
60
Glycopeptides Bacterio_____
Bacteriocidal
61
Macrolides Spectrum
Gram +
62
Macrolides Mode of Action
Protein synthesis
63
Macrolides Examples
Erythromycin
64
Macrolides
| Bacterio_____
Bacteriostatic
65
Fluoroquinolones spectrum
Both
66
Fluoroquinolones Mode of Action
inhibit DNA synthesis by binding DNA gyrases
67
Fluoroquinolones Examples
Levofloxacin
68
Fluoroquinolones
| Bacterio_____
Bacteriocidal
69
Azoles Spectrum
Fungi
70
Azoles Mode of Action
disrupts fungal cell membrane
71
Azoles Examples
Fluconazole
72
Azoles Bacterio_____
Bacterostatic
73
Supplemental AST testing - when
detect complicated resistance mechanisms not evident on routine AST testing
74
Supplemental AST testing predictor drugs
oxacillin disk screen for penicillin resistance in strep pneumoniae
75
Beta lactamase testing
Visual detection of beta lactamase hydrolysis - colormetric reaction
Enzyme will disrupt the beta lactam ring. Wont bind to PBP and inhibit cell wall synthesis
76
Beta lactamase method
Chromogenic cephalosporin and acidometric - included on Neisseria test strip. Not useful for Enterobacteriaceae or Pseudomonas
77
You have been asked to perform QC (quality control ) on a new kit of API20E strips. . Is this function preanalytic, analytic, or postanalytic
Analytic
78
You have been asked to perform QC (quality control ) on a new kit of API20E strips. Name 3 possible organisms that would be appropriate for QC.
Gram negative rods from Enterobacteriaciae group or 2 from Entero and 1 non-Entero
79
You have been asked to perform QC (quality control ) on a new kit of API20E strips. What criteria should determine the organisms to be used?
Organisms that represent positive and negative reactions for all 20 test wells.
80
You have been asked to perform QC (quality control ) on a new kit of API20E strips. How can you be certain of the biochemical characteristics of the organisms used?
Using specific ATCC organisms recommended by the manufacturer
81
You have been asked to perform QC (quality control ) on a new kit of API20E strips. What type of information should be documented in the QC record for this testing?
```
Lot number
Expiration date
Test results
Tech performing test
Date
```
82
You have been asked to perform QC (quality control ) on a new kit of API20E strips. If erroneous results are obtained, name 3 sources of error.
Tech error - inoculum too heavy/light
Mixed culture
Incubation time/temp
Problems with kit - manufacturer or transport
83
A patient has been diagnosed with a UTI. A culture is sent to the lab and K. pneumonia has been identified. Name 2 testing methods that can be utilized to determine the susceptibility of various antimicrobials.
Disk diffusion and MIC
84
A patient has been diagnosed with a UTI. A culture is sent to the lab and K. pneumonia has been identified. Name 2 bacteriocidal antimicrobials that may be effective.
Gentamycin
Ceftriaxone
Levofloxacin
85
A patient has been diagnosed with a UTI. A culture is sent to the lab and K. pneumonia has been identified.. Name 2 bacteriostatic antimicrobials that may be effective
Tetracycline
Trimethoprim
Tigecycline
86
A patient has been diagnosed with a UTI. A culture is sent to the lab and K. pneumonia has been identified. The lab did not test this organism for vancomycin, why?
Ineffective against gram neg organisms
87
A patient has been diagnosed with a UTI. A culture is sent to the lab and K. pneumonia has been identified. Should levoflaxacin be tested?
Yes. Generally it is effective but acquired resistance is always possible.
88
A patient has been diagnosed with a UTI. A culture is sent to the lab and K. pneumonia has been identified. Does this organism exhibit intrinsic resistance to any antimicrobials?
Yes. Ampicillin and other beta lactams
89
Conditions for disk diffusion testing of S. aureus must come from which document?
CLSI
90
What type of light source should be used to view a disk diffusion plate
Reflected light
91
Supplemental AST testing is often required. What is the necessity for aminoglycoside screens
Detection of high-level resistance (HLAR) aminoglycoside
92
What is the test method utilized when CRE type resistance is suspected?
Modified Hodge Test
93
Name 2 methods for measuring the turbidity of the inoculum
McFarland Standard
| Spectrophotometer
94
Name 2 criteria for selection of antimicrobial agents to be tested
Site of infection
method
availability
known resistance patterns
95
Class/spectrum of activity for:
| Ampicillin
Beta lactam, both
96
Class/spectrum of activity for:
| Cefazolin
Beta lactam, both
97
Class/spectrum of activity for:
| Clindamycin
Lincosamide, gram pos (rarely gram neg)
98
Class/spectrum of activity for:
| Levofloxacin
quinolone, both
99
Class/spectrum of activity for:
| Piperacillin
Beta lactam, both
100
Class/spectrum of activity for:
| Ticarcillin/Clav acid
Beta lactam combo, both
101
Class/spectrum of activity for:
| Trime/Sulfa
combo, both
102
What are the possible problems and what measures should be taking if the following are observed when performing QC? Several E. coli zones are too large
Check inoculum
medium depth
medium pH
103
What are the possible problems and what measures should be taking if the following are observed when performing QC? Small colonies within the zone of tetracycline with S. aureus
Mixed culture
reisolate
resistant mutants
104
What are the possible problems and what measures should be taking if the following are observed when performing QC? Gentamycin zone too small with P. aeruginosa
Ca and/or Mg level too high in medium
105
What is the relationship between MIC and zone size?
1. Regression graph
| 2. MIC breakpoints plotted against zone sizes, regression line is drawn. DD breakpoints are where lines intersect.
106
An organism with an increased MIC value will be expected to have an increased or decrease zone size?
Decreased
107
Name the 3 weekly QC organisms used for KB method
E. coli - 25922
P. aerug - 27853
S. aureus - 25923
108
Describe the action of the amoxicillin or ticarcillin/clavulanic acid combo
2 beta lactams- lactam/lactamase inhibitor. Inhibitor renders B-lactamase incapable, beta lactam drug exerts its activity
109
An oxacillin disk is used to test S. pneumoniae for penicillin. Why?
Due to increased resistance observed with penicillin, OX is more sensitive and reliable indicator.
110
Define empiric antimicrobial therapy
therapy that is started before knowing organism or susc. profile
