Week 6: Laboratory Approaches Flashcards
(128 cards)
1
Q
Labs in Canada are licensed under what?
A
PHAC
2
Q
In Canada, all facilities handling and storing human pathogens and toxins, such as public health labs, teaching and research labs, diagnostic labs in hospitals, and vaccine production plants are licensed under what?
A
-Human pathogens and Toxins Act (HPTA)
-Humans Pathogens and Toxins Regulations (HPTR)
3
Q
containment (or biocontainment) is a combination of what?
A
physical design parameters and operational practices that protects the personnel, immediate work environment, the community, and the external environment from exposure to potentially hazardous biological material
4
Q
how many containment levels are there?
A
4
5
Q
Which containment level are most labs?
A
2 or 3
6
Q
Describe CL1
A
biological material can be safety performed in a basic laboratory work area, large scale production area, or minimal work area
7
Q
what microorganisms might a CL1 facility handle?
A
-bacillus subtilis
-non pathogenic E. coli
8
Q
Which labs are often found in hospital settings?
A
CL2
9
Q
which labs often have biosafety cabinets to protect from pathogen exposure?
A
CL2
10
Q
Pathogens worked on in CL2 labs are mainly spread through ____ and ___
A
injection or ingestion
11
Q
what are some examples of pathogens that would be handled in a CL2 lab?
A
-herpes
-E. coli
-Salmonella
12
Q
What are some operational practices for CL2 labs?
A
-administrative (biosafety program management, safety)
-procedures (work practices, personal protective equipment, decontamination)
13
Q
Which lab requires negative pressure with HEPA filtration for exhaust air?
A
CL3
14
Q
What pathogens do CL3 labs handle?
A
-West Nile
-anthrax
-tuberculosis
15
Q
True or false. In CL3 labs, the air is purified, scientists must take shower before exiting, and the waste is disinfected before leaving the facility?
A
True
16
Q
With what containment level is the entire lab built with extra walls to prevent a potential breach (built as a box-within-a-box)
A
CL4
17
Q
With what contaminate level do scientists work with a dedicated breathing air supply and take chemical showers to decontaminate their suits
A
CL4
18
Q
CL4 labs have layers of what to ensure air always flows back into the lab when doors are open?
A
negative pressure zones
19
Q
When Canada must prepare for deadly global outbreaks of pathogens like Ebola, Nipah virus, and Lassa fever, where is the research done?
A
CL4 labs
20
Q
What organisms are tested at CL4 labs?
A
-Gonorrhea
-streptococcus
-TB
-E. coli
-Listeria
-Salmonella
-Shigella
-Measles
-Zika
-Rabies
-Ebola
21
Q
How often are biological risk assessments completed?
A
annually
22
Q
Define agent hazards
A
review potential biological agents and their hazardous characteristics including capability to infect and cause disease
23
Q
What do lab procedures focus on??
A
focus on equipment and procedures that generate aerosols, use of sharps, etc
24
Q
A risk assessment can be __ and involves what health department?
A
subjective; Occupational
25
define skill evaluation
evaluate expertise and proficiency of staff following safe procedures
26
Is the infectious nature usually known?
No, except in rare circumstances
27
initial processing of clinical specimens and serological identification of isolates can be done safely at what level?
CL2
28
BSC, PPE, or other physical contaminant devices must be used wen
a) procedures with potential for creating infectious aerosols or splashes are conducted
b)high concentrations or large volumes of infectious agents are used
29
The essential element for protection when transporting biohazardous materials is
triple-containment packaging
30
What type of swab would be used for an ARO?
-nasal
-rectal
-wound
31
how can specimens be collected?
-nasopharnygeal
-stool specimens
-blood collection
-CSF collection
-environmental swabs
-food collection
32
What are the 5 common criteria for MRSA/VRE screening?
1. previous hospital admission (within 12 months)
2. Any patient who has been admitted to a hospital outside of Canada in the last 12 months
3. any patient who resides in a communal living setting
4. any patient who has a previous MRSA/VRE infection or colonization history
5. Patients admitted to ICU
33
nose swabs test for
MRSA
34
rectal swabs/stoma swabs test for
MRSA, or MRSA and VRE
35
stool cultures test for
MRSA, or MRSA and VRE
36
Draining a wound tests for
MRSA
37
True or false. Feces must be visible on the swab with a rectal swab
True
38
If there is more than one open wound, which one do you swab?
the one with the most drainage
39
when collecting urine from catheter collect from
tubing not the bag
40
how would you collect a specimen from a bedpan?
aspirate the specimen from the bedpan or clean the bedpan to prevent specimen contamination
41
Define a colony count
a pre-determined standard amount of urine is placed onto an agar plate using a calibrated loop and the number of colonies growing are counted
42
mulitple organisms (more than 3 different bacteria) suggests the specimen is what?
contaminated
43
stool collection should be collected in a manner than prevents contamination from what?
urine and water
44
do you need a large amount of stool for stool collection?
no. you need an amount the size of a raisin or until fluid level is raised to line on container. Stools produce gases so if you overfill the container can explode
45
You must make sure appropriate transportation media is used for tests required with stool collection. An example of this is
C. diff should be stored in a container with no media
46
When should stool collection be done?
-patient with one episode of vomitting and one loose stool in 24 hours
-two or more loose stools in a 24 hour period and (other critieria in notes)
47
stool for C. diff is tested for what?
toxin
48
specimens for C. diff collection must be
liquid stool
49
is culture done for C. diff?
no
50
How are stool specimens for C. diff tested?
two step lab screening and confirmatory test process
-screening: glutamte dehydrogenase antigen and toxins A/B with rapid enzyme immunoassay
-testing for C. diff toxin gene with a molecular LAMP assay
51
which lab reports don't contain a susceptibility report?
pathogens that are self-limiting and don't require treatment
52
lab reports that should contain a suscepibility report are for
pathogens that require treatment
53
A negative lab report should include
what the specimen was examined for
54
presence of ___ in any amount is significant
parasite
55
a ___ culture requires special transport media obtained from the lab
viral culture
56
travel and antibiotic history are important when
diarrhea is present
57
throat swabs for culture are only significant for what m.o.?
group A strep
58
why is no susceptibility report generated for Group A strep?
becuase it is considered universally sensitive
59
how would you collect a throat swab?
have the patient open mouth wide and depress tongue with a tongue depressor. Gently swab mucosa behind uvula and between tonsils
60
nasopharyngeal swab specimen should be stored and transported at what temp?
between 2-8 degrees celcus
61
For a sputum collection, what specimens can be collected?
-sputum
-trachel aspirate
-bronchoalveolar lavage
-esophageal brushing
-lung tissue
62
how much material do you want to collect for tracheal aspirates?
as much as possible
63
when collecting bronchial washings, what should you avoid and why?
contaminating the bronchoscope with tap water as saprophytic mycobacteria may produce false-positive culture
64
which specimens must you NOT freeze?s
sputum collection
65
what are recommended specimens for MRSA?
-perianal
-skin lesions
-anterior nares
66
What are the recommended specimens for VRE?
-stool/rectal anal swab (stool preferred)
-swabs from colostomy site if present
67
with MRSA, the same swab can be used for what? different swabs must be used for what?
-same for both nares
-different for anal region and all wounds
68
with VRE swab, swab around what area? Insert into rectum if there is no visible stool
external rectal orfice
69
with what m.o. must you not collect specimens for microbiological examination before consulting with the PHO lab microbiologist?
Ebola
70
What are some components of collecting wound specimen?
--the wound should be cleansed with saline to avoid contamination of the culture by surface organisms
-do not collect exudate or pus
-select the cleanest area of wound (firmly press and rotate the swab in this area)
-include tunnelling if present
71
which microorganism requires the initiation of the Emergency Response Assistance Plan, special shipping and handling?
Ebola
72
specimens for malaria testing collected from suspected or confirmed VHF cases are subject to part 7 of what?
the Transport Canada Transportation of Dangerous Goods regulation
73
When should viral hemorrhagic fever like Ebola be suspected?
in patients with fever and relevant travel history to endemic exposure areas within 21 days of illness onset?
74
During the collection procedure, the specimen container must be labelled with what information?
the patients full name, date of collection, and one other unique identifier such as the patients date of birth or health card number
75
when reporting an injury to the Occupational Health Department, the medical provider's description of the injury should include what information?
-the potential infectious agent
-the mechanism and route of exposure
-time and place of the incident
-PPE used at the time of event
-First aid provided
-Department supervisor, witness
76
What are examples of environmental specimens that can be collected?
-water
-sewage
-air
-ultrasound gels
-sink/P trao
-birthing tubs
77
how should results be interpreted?
based on the patient's clinical presentation, risk factors, and exposure history
78
define accuracy
the closeness of the result obtained to the true value and is described by two terms
79
who two terms define accuracy?
specificity and sensitivity
80
Define sensitivity
Detect all true cases of the disease, or the absence of false-negative results. Sensitivity is the number of true-positive results over the number of true positive plus false negative results
81
Both sensitivity and specificty and ___ and expressed as ___
proportions; percentage
82
define specificity
the number of true negative results over the number of true negatives plus false positive results
83
define precision
repeat testing on the same sample consistently provides the same or similar results
84
what is screening used to do?
identify a disease without signs or symptoms in large patient populations
85
screening tests have high ___ but low ___
sensitivity but low specificity
86
A definitive diagnosis can be given by detecting an immunological response. What type of reaction is this?
Ag-Ab specific to the infecting agent in the patient's serum
87
antigens are usually __ or ___
proteins or polysaccharides
88
what do antigens do?
stimulate the immune system to produce antibodies such as immunoglobulins
89
Does antigen detection directly identify the presence of infectious agents?
Yes
90
what are examples of antigen detection tests?
-agglutination tests
-immunofluorescence
-enzyme linked immunosorbent assay (ELISA)
91
what are some microorganisms detected by antigen?
-HIV
-streptococcus pneumoniae
-Neisseria meningitidis
-group B streptococcus
-Cryptococcus spp
-Hep B envelop
-Hep B surface
-Legionella
-COVID-19
92
antibody or immunoglobulin are a product of what?
acquired immunity
93
what produces antibodies?
B lymphocytes
94
What are 4 types of diagnostic tests?
1. antibody detection
2. antigen detection
3. molecular diagnostic testing
4. tests for infectious process
95
Antibodies attach to a specific
antigen
96
antibody tests can be used to detect what agents?
-chlamydia
-Hep A
-Hep B envelop
-Hep B surface
-Hep B core
-Giardia
-helicobacterpylori
97
True or false. All molecular tests can read as false positive due to possible sample contamination
True
98
What are 3 types of molecular diagnostic tests?
1. Target Amplification Methods
2. Probe Amplification Methods
3. Signal Amplification Methods
99
Describe tests for infectious processes
body fluid obtained using sterile technique
100
When is cerebrospinal fluid collected?
when meningitis is suspected
101
Cloudy CSF indicates
bacterial infection
102
clear or hazy CSF indicates
viral or fungal infection
103
What is CSF analyzed for?
color and clarity, protein, glucose, and WBC (including differential)
104
what can body fluid be analyzed for?
-total protein
-specific gravity
-cell count
-different (types of WBC present)
-body fluid glucose
-gram stain
-culture
105
E. Coli and Klebsiella that are resistant to carbapenems should be presumed
carbapenemase producers until proven otherwise
106
True or false. Some gram-negative bacteria may be resistant to carbapenems by other means (not producing carbapenamese)
True
107
Which bacteria are resistant to carbapenems without producing carbapenemase?
-Proteus and Providencia spp.
-Enterbacter
-Acinetobacter
-pseudomonas
108
True or false. Specimens with a single target detected will be reported as COVID-19
virus detected
109
when is a test reported as invalid?
-results on uninterpretable (usually due to failed detection of assay control)
-CT values
110
What is the positive predictive value of a PCR test?
close to 100%
111
A positive result for Hep A IgG (in the absence of Hep A IgM) indicates
immunity to Hep A virus
112
A positive result for Hep A IgM with or without a positive Hep A IgG suggests
recent/acute infection with Hep A
113
Hep B surface antigen (HBsAG) indicates
that the person is infectious
114
HBsAG can be detected in high levels during
acute or chronic Hep B virus infection
115
Hep B surface antibody (anti-HBs)
indicates recovery and immunity from Hep B infection (or someone vaccinated against Hep B)
116
Total Hep B core antibody (anti-HBc)
appears at the onset of symptoms in acute Hep B and persists for life
117
the presence of anti-HBc indicates
previous or ongoing infection with hep B virus in an undefined time frame
118
IgM antibody to Hep B core antigen (IgM anti-HBc) indicates
positivity indicates recent infection with Hep B virus
119
What specimen types can be collected for measles?
-nasopharyngeal swab
-throat swab
-urine
-CSF
120
How much urine and how much CSF must be collected for measles testing?
50ml; 1ml
121
What are the 4 specimen collection methods for pulmonary TB?
1. sputum induction
2. bronchoscopy
3. coughing
4. gastric aspiration
122
describe how an AFB test is classified for TB
according to the number of acid-fast bacilli seen, the smears are classified as 4+, 3+, 2+, or 1+
123
Can TB be detected by culture?
Yes
124
What is the current gold standard for detection of active TB disease?
mycobacterial culture
125
what is the most senstiive test for detecting active TB?
mycobacterial culture
126
True or false. A single-definitive culture for M. tuberculosis is considered definitive for active disease
True
127
True or false. Every specimen that is sent for smear microscopy is submitted for culture
True
128
Describe nucleic acid amplification tests (NAAT)
the amplification of nucleic acids for the diagnosis of TB or to detect drug resistance is a sensitive method faster than culture methods
