SPECIMEN MANAGEMENT Flashcards
1
Q
True or false:
Appropriate collection technique : acute (early) phase of an illness
A
True
2
Q
How soon should specimens be collected for viral infections?
A
Within 2-3 days
3
Q
When should specimens be collected in relation to starting antimicrobials, antifungals, or antiviral medications?
A
Before these medications are started
4
Q
How soon should specimens be transported after collection?
A
Within 2 hours of collection
5
Q
What are the requirements for specimen containers during transport?
A
Containers must be:
leak-proof and transported within sealable
plastic bags with a separate section for paperwork
6
Q
What label should be marked on specimen transport bags?
A
biohazard label
7
Q
What additional measures might be required for transporting specimens?
A
Use of special preservatives, temperature-controlled conditions, or holding media
8
Q
What preservative is used for urine specimens?
A
boric acid
9
Q
Which preservatives are used for stool specimens intended for ova and parasite examination?
A
Polyvinyl alcohol (PVA) and buffered formalin
10
Q
What are common transport or holding media for specimens?
A
Stuart’s medium and Amie’s medium
11
Q
Why is charcoal added to some transport media?
A
TO ABSORB FATTY ACID
12
Q
What anticoagulant is commonly used for specimen preservation?
A
0.025% Sodium polyanethol sulfonate (SPS)
13
Q
Which anticoagulant is used for viral cultures
A
Heparin
14
Q
True or false:
Citrate and EDTA can e used for specimen preservation
A
false
15
Q
What is the recommended temperature for storing specimens in a refrigerator?
A
4°C
16
Q
At what temperature should specimens be stored at ambient (room) temperature?
A
22°C
17
Q
What is the storage temperature for specimens requiring body temperature conditions?
A
37°C
18
Q
What are the recommended freezer temperatures for storing specimens?
A
-20°C or -70°C
19
Q
What types of specimens are typically stored at 4°C?
A
Urine
Stool
Viral specimens
Sputum
swabs
foreign devices (catheters)
20
Q
How long can serum for serologic studies be stored at -20°C?
A
1 week
21
Q
What temperature is recommended for long-term storage of tissues or specimens?
A
-70°C
22
Q
True or False:
Rejection criteria include specimens where information on the label does not match the request or the specimen is unlabeled.
A
True
23
Q
True or False:
Specimens transported at improper temperatures may be rejected.
A
True
24
Q
True or False:
Specimens not transported in the proper medium may be rejected.
A
True
25
True or False:
Insufficient quantity of specimens can lead to rejection.
True
26
True or False: Leaking specimens may be rejected.
True
27
True or False:
Specimens with transport times exceeding 2 hours post-collection or those not properly preserved may be rejected.
True
28
True or False:
Specimens received in a fixative like formalin, which kills microorganisms, may be rejected.
True
29
True or False: Specimens received for anaerobic culture from sites known to have anaerobes as part of the microbiota (e.g., vagina, mouth) may be rejected.
True
30
True or False:
Dried specimens are generally acceptable for processing.
False
31
True or False:
Specimens that would produce information of questionable medical value upon processing, such as Foley catheter tips, may be rejected.
True
32
According to processing guidelines, which specimens should be given priority when multiple specimens arrive simultaneously?
CSF, tissue, blood, and sterile body fluids
33
What action should be taken upon the arrival of a specimen in the laboratory?
Record the time and date of specimen receipt
34
What should a microbiologist do if a specimen arrives with multiple test requests but there is insufficient specimen volume to perform all tests?
Call the clinician to prioritize the testing
35
What is the initial step in processing specimens according to guidelines?
Perform a gross examination of the specimen
36
What characteristic of stool should be noted, which may indicate the presence of barium?
chalky white color
37
What aspect of the specimen's status should be noted during gross examination?
Whether it is bloody, clouded, or clotted
38
What is the purpose of direct microscopic examination of a specimen?
To assess the quality of the specimen
39
True or False: Direct microscopic examination is commonly performed on throat, nasopharyngeal, or stool specimens.
False (Usually not performed on these types of specimens)
40
What is the most common staining method used in bacteriology for direct microscopic examination?
Gram staining
41
What are some common stains used for direct fungal examination?
1.KOH (Potassium hydroxide)
2. PAS (Periodic acid-Schiff)
3.GMS (Grocott’s methenamine silver stain)
4. calcofluor white
42
What are examples of common stains used for direct acid-fast staining?
1.Auramine rhodamine
2. Ziehl-Neelsen
3. Kinyoun
43
It is a liquid medium where nutrients are dissolved in water, and bacterial growth is indicated by a change from clear to turbid appearance.
Broth medium
44
example of pH indicator used in broth medium
phenol red
45
what indicator used in broth medium where They change color in the presence of metabolites, indicating bacterial activity.
pH indicator
46
It is a semisolid medium that provides an indication of the type of organism present based on oxygen requirements.
Thioglycollate broth
47
How are pH indicators such as phenol red used in broth medium?
They change color in the presence of metabolites
48
What is the purpose of thioglycollate broth in microbiological media?
provides an indication of the type of organism present based on oxygen requirements.
49
a solid medium used to solidify nutrients and water to support bacterial growth.
Agar
50
Most common solidifyng agent in agar
Agarose
51
Agarose melts at high temperatures (___°C) but resolidifies when the temperature falls below __°C.
High temp - >95 C
Low temp - below 50 C
52
What type of growth medium combines both liquid and solid phases?
Biphasic medium
53
How can the growth of bacteria in broth medium be detected?
By observing a change in the broth's appearance from clear to turbid, indicating bacterial growth.
54
what culture media: contain nutrients that support the growth of most nonfastidious organisms and are nonselective but differential.
Nutritive media
55
Name 3 examples of nutritive media used for bacterial and fungal growth.
1.tryptic soy agar (bacteria)
2.nutrient agar plates for bacteria,
3. Sabouraud’s dextrose agar for fungi, as well as blood or chocolate agar.
56
These culture media contain specific nutrients needed for the growth of bacterial pathogens
supplemental or enrichment media
57
Culture media: Buffered charcoal-yeast extract (BCYE) for Legionella pneumophila.
Supplemental or Enrichment Medium
58
Culture media: They are specialized to enhance the growth of organisms present in low numbers, like anaerobes or those affected by antimicrobial therapy.
Enrichment broth
59
Culture media: Back up broth
Enrichment broth
60
What is an example of an enrichment broth used for anaerobic cultures?
1. Thioglycollate broth (anaerobes)
2. Brain heart infusion broth (BHIB)
3. Tryptic soy broth (TSB)
4. Gram negative broth
61
What is the purpose of LIM broth (Todd Hewitt broth with colistin and nalidixic acid)?
It is used for selective enrichment of organisms such as Streptococcus pneumoniae.
62
How do selective media distinguish between groups of organisms?
By incorporating antimicrobials, dyes, or alcohol to support the growth of one group of organisms while inhibiting another.
63
What antimicrobial agent is used in MacConkey agar to inhibit gram-positive organisms?
Crystal violet
64
It contains colistin and nalidixic acid, which inhibit the growth of gram-negative organisms.
Columbia agar
65
Columbia agar contains?
Colistin and nalidixic acid
66
True or false:
Selective media can also be differential media
True
67
Culture media: They employ specific factors that allow colonies of one bacterial species or type to exhibit certain metabolic or culture characteristics.
Differential media
68
What characteristic of MacConkey agar allows it to differentiate between bacteria?
It differentiates between gram-negative bacteria based on their ability to ferment lactose.
69
It differentiates between gram-negative bacteria based on their ability to ferment lactose.
MacConkey agar
70
What type of medium is Brain-heart Infusion (BHI)?
It can be either a broth or agar medium
71
True or False: BHI only without blood
False (both with and without blood)
72
What carbohydrate does Brain-heart Infusion (BHI) contain
dextrose
73
Culture media: It is often used for culturing patient blood samples to detect bacterial infections.
BHI broth
74
Culture media: Baacterial Susceptibility
Brain heart Infusion
75
What components are essential for Chocolate Agar to support the growth of organisms like Neisseria gonorrhoeae and Haemophilus spp.?
1.Hemoglobin
2. hemin (X factor),
3. nicotinamide adenine dinucleotide (NAD, V factor),
which are released during lysis.
76
Chocolate Agar to support the growth of organisms like
Neisseria gonorrhoeae and Haemophilus spp
77
True or false: Neisseria gonorrhoeae and Haemophilus spp groows on sheep blood agar
False (neither)
78
Why do Neisseria gonorrhoeae and Haemophilus spp. not grow on sheep blood agar but thrive on Chocolate Agar?
Because Chocolate Agar provides specific growth factors like hemin and NAD that are not present in sheep blood agar.
79
What are the main components of Columbia CNA agar with blood?
It consists of Columbia agar base supplemented with 3 peptone sources and 5% defibrinated sheep blood.
80
It differentiates based on hemolytic reactions, which can indicate the ability of bacteria to break down red blood cells.
Columbia CNA with blood
81
CNA means
Colistin and nalidixic acid
82
It is a selective broth used for cultivating gastrointestinal pathogens from stool specimens and rectal swabs.
Gram negative broth
83
What selective components are present in Gram-Negative Broth?
1. Sodium citrate,
2. sodium deoxycholate (bile salt),
2. mannitol as the primary carbon source.
84
serves as the primary carbon source, supporting the growth of targeted gastrointestinal pathogens in the medium.
Mannitol
85
What carbohydrates are included in Hektoen Enteric Agar, and what is their purpose?
Lactose, sucrose, and salicin, which help differentiate bacteria based on their ability to ferment these sugars.
86
How does Hektoen Enteric Agar detect hydrogen sulfide (H2S) production?
It contains ferric ammonium citrate, which reacts with H2S to form a black precipitate.
87
Hektoen enteric (HE) agar is a medium that relies on the use of ________for selective inhibition
bile salts
88
What is the primary dye used in MacConkey Agar, and what is its role?
Crystal violet, which inhibits the growth of Gram-positive bacteria.
89
How does MacConkey Agar differentiate between lactose-fermenting and non-lactose-fermenting bacteria?
It uses a pH indicator, neutral red, which turns pink when lactose is fermented, indicating acid production.
90
What pH indicator is used in Hektoen Enteric Agar?
Bromthymol blue.
91
What type of medium is Hektoen Enteric Agar classified as?
Differentail medium
(not sure if also selective)
92
What specific carbohydrate is used in MacConkey Agar to differentiate bacterial colonies?
lactose
93
What is Phenylethyl Alcohol Agar (PEA) primarily used for?
provide nutrients for common gram (+) cocci
94
What component in PEA inhibits gram-negative bacteria?
Phenylethyl alcohol
95
What type of agar is Phenylethyl Alcohol Agar based on?
Sheep blood agar
96
Which common gram-positive cocci are supported by PEA?
Enterococci, streptococci, and staphylococci.
97
Why should PEA not be used for interpreting hemolysis?
The phenylethyl alcohol can interfere with the appearance of hemolysis, making it unreliable for such assessments.
98
What is the primary purpose of adding phenylethyl alcohol to the agar?
To inhibit the growth of gram-negative bacteria.
99
What type of bacteria does Sheep Blood Agar support the growth of?
All but the most fastidious clinically significant bacteria.
100
What are the primary components of Sheep Blood Agar?
Tryptones
soybean protein digest, sodium chloride,
agar,
5% sheep blood
101
What does the soybean protein digest provide in Sheep Blood Agar?
It contains natural carbohydrates and additional nutrients.
102
What are the three types of hemolysis that can be interpreted on Sheep Blood Agar?
Alpha hemolysis (partial, greenish discoloration), beta hemolysis (complete, clear zone), and gamma hemolysis (no hemolysis).
103
What hemolysis : A greenish discoloration around the colonies
Alpha
104
What type of medium is Modified Thayer-Martin Agar?
It is an enrichment and selective medium.
105
What is the enrichment component in Modified Thayer-Martin Agar?
Chocolatized blood.
106
What are the antibiotics included in Modified Thayer-Martin Agar and their targets?
Colistin: Inhibits gram-negative bacteria (excluding Neisseria species).
Vancomycin: Inhibits gram-positive bacteria.
Nystatin: Inhibits yeast.
Trimethoprim: Inhibits Proteus species.
107
Why is Modified Thayer -Martin Agar is also a selective medium
due to the antibiotics
108
What distinguishes Martin-Lewis Agar from Modified Thayer-Martin Agar?
Martin-Lewis Agar uses asamycin instead of nystatin and includes a higher concentration of vancomycin.
109
What type of medium is Thioglycollate Broth?
It is an enrichment broth or semisolid medium.
110
What components in Thioglycollate Broth provide essential nutrients for bacterial growth?
Casein, yeast and beef extracts, and vitamins.
111
It is an oxidation-reduction indicator that changes color in the presence of oxygen in Thioglycollate Broth
resazurin
112
What additional nutrients can be found in modified Thioglycollate Broth?
Dextrose, vitamin K, and hemin.
113
It prevent convection currents from carrying atmospheric oxygen, maintaining anaerobic conditions Thioglycollate Broth
0.075% agar
114
What is the function of thioglycolic acid in Thioglycollate Broth?
It acts as a reducing agent to create and maintain an anaerobic environment.
115
What type of medium is Xylose-Lysine Deoxycholate (XLD) Agar?
It is a selective and differential medium for Shigella and Salmonella
116
What components in XLD Agar inhibit the growth of gram-positive bacteria?
Salt and sodium deoxycholate.
117
It is a pH indicator that changes color based on the fermentation of carbohydrates in XLD agar
phenol red
118
Which carbohydrates are present in XLD Agar?
Lactose, xylose, and sucrose.
119
XLD agar : Initially yellow due to xylose fermentation, then red after lysine decarboxylation, and black if hydrogen sulfide is produced.
Salmonella
120
XLD agar: Red colonies as it does not ferment xylose or decarboxylate lysine, and does not produce hydrogen sulfide.
Shigella
121
What type of medium is Eosin Methylene Blue (EMB) Agar?
It is a selective and differential medium for gram-negative enteric bacilli.
122
What carbohydrate is present in EMB Agar?
lactose
123
What are the indicators in EMB Agar?
Eosin Y and methylene blue.
124
How do lactose fermenters appear on EMB Agar?
They produce dark colonies with a green metallic sheen.
E.g E.coli
125
How do non-lactose fermenters appear on EMB Agar?
They form colorless or light pink colonies.
Ex.
Salmonella and shigella
126
What type of medium is Salmonella-Shigella Agar?
selective
127
What inhibitor is used in Salmonella-Shigella Agar?
Brilliant green
128
What carbohydrate is present in Salmonella-Shigella Agar?
lactose
129
What is the indicator in Salmonella-Shigella Agar?
netral red
130
They are used to detect hydrogen sulfide production, resulting in black centers in colonies of hydrogen sulfide-producing bacteria in Salmonella-shigella agar
Ferric citrate and sodium citrate
131
What type of medium is Thiosulfate Citrate-Bile Salts (TCBS) Agar?
It is a selective and differential medium for Vibrio species.
132
What indicator is used in TCBS Agar?
Bromthymol blue. (based on fermentation of SUCROSE)
133
What are the main nutrient components in TCBS Agar?
Yeast extracts,
bile salts,
citrate,
sucrose,
ferric citrate,
sodium thiosulfate.
134
How does Thiosulfate citrate-bile salts Agar differentiate Vibrio species?
Through the fermentation of sucrose and the production of hydrogen sulfide, which changes the color of the medium.
135
What type of medium is Trypticase Soy Broth (TSB)?
It is an all-purpose enrichment broth.
136
what broth: It can support the growth of many fastidious and nonfastidious bacteria.
Trypticase soy broth
137
Its purpose is It is used for subculturing various bacteria from primary agar plates.
Trypticase soy broth
138
What type of bacteria uses oxygen as the terminal electron acceptor and grows well in room air?
Aerobic bacteria
139
What type of bacteria finds oxygen inhibitory or lethal?
Anaerobic
140
What term describes bacteria that can grow in the presence or absence of oxygen?
Facultative anaerobic bacteria.
141
What type of bacteria cannot grow in the absence of oxygen?
Strictly aerobic bacteria.
142
What type of bacteria grows only in low levels of oxygen (approximately 20% or less)?
Microaerophilic or microaerobic bacteria.
143
What term describes bacteria that grow slowly and poorly in the presence of oxygen?
Aerotolerant bacteria.
144
What type of bacteria grows best with higher carbon dioxide concentrations (5-10%)?
Capnophilic bacteria.
145
Capnophilic bacteria grows best with higher oxygen concentrations.
With a percentage range of.
5-10%
146
What temperature range is similar to those of internal human host tissues and organs, ideal for most bacterial growth?
35-37°C.
147
Which bacteria require cold enrichment for optimal growth, and what temperature range does this entail?
Listeria monocytogenes and Yersinia enterocolitica; 4-43°C.
148
What pH range is near neutral and ideal for bacterial growth?
6.5-7.5.
149
How does increased atmospheric humidity affect the growth of certain bacterial species?
It enhances their growth.
150
What is the ideal incubation temperature for fungi?
28-30°C. (room temp)
151
At what temperature should bacteria, viruses, and acid-fast bacillus be incubated?
35-37°C.
152
What is the typical oxygen concentration and carbon dioxide for aerobes during incubation?
21% oxygen in ambient air.
0.03% of carbon dioxide
153
What type of environment is required for anaerobes during incubation?
An environment with 5%-10% hydrogen, 5-10% carbon dioxide, 80-90% nitrogen, and 0% oxygen, using an anaerobe jar, bags, or chambers
154
What concentration of carbon dioxide and oxygen do capnophiles (e.g., H. influenzae and N. gonorrheae) require?
Increased concentrations of 5-10% carbon dioxide and approximately 15% oxygen.
155
How can increased carbon dioxide and reduced oxygen be achieved for capnophiles?
Using candle jars (3% carbon dioxide), carbon dioxide incubators, chamber jars, or bags.
156
What conditions are necessary for microaerophiles (e.g., C. jejuni, H. pylori) during incubation?
Reduced oxygen (5-10%) and increased carbon dioxide (8-10%).
