Micro-Specimen Collection, Media, and Methods Flashcards
1
Q
- The aseptic collection of blood cultures requires
that the skin be cleansed with:
A. 2% iodine and then 70% alcohol solution
B. 70% alcohol and then 2% iodine or an
iodophor
C. 70% alcohol and then 95% alcohol
D. 95% alcohol only
A
B. 70% alcohol and then 2% iodine or an
iodophor
2
Q
- When cleansing the skin with alcohol and then
iodine for the collection of a blood culture, the
iodine (or iodophor) should remain intact on
the skin for at least:
A. 10 sec
B. 30 sec
C. 60 sec
D. 5 min
A
C. 60 sec
3
Q
- What is the purpose of adding 0.025%–0.050%
sodium polyanetholsulfonate (SPS) to nutrient
broth media for the collection of blood cultures?
A. It inhibits phagocytosis and complement
B. It promotes formation of a blood clot
C. It enhances growth of anaerobes
D. It functions as a preservative
A
A. It inhibits phagocytosis and complement
4
Q
- A flexible calcium alginate nasopharyngeal swab
is the collection device of choice for recovery of
which organism from the nasopharynx?
A. Staphylococcus aureus
B. Streptococcus pneumoniae
C. Corynebacterium diphtheriae
D. Bacteroides fragilis
A
C. Corynebacterium diphtheriae
5
Q
- Semisolid transport media such as Amies, Stuart,
or Cary–Blair are suitable for the transport of
swabs for culture of most pathogens except:
A. Neisseria gonorrhoeae
B. Enterobacteriaceae
C. Campylobacter fetus
D. Streptococcus pneumoniae
A
A. Neisseria gonorrhoeae
6
Q
- Select the method of choice for recovery of
anaerobic bacteria from a deep abscess.
A. Cotton fiber swab of the abscess area
B. Skin snip of the surface tissue
C. Needle aspirate after surface decontamination
D. Swab of the scalpel used for débridement
A
C. Needle aspirate after surface decontamination
7
Q
- Select the primary and differential media of choice
for recovery of most fecal pathogens.
A. MacConkey, blood, birdseed, and Campylobacter
(Campy) agars
B. Hektoen, MacConkey, Campy, colistin–nalidixic
acid (CNA) agars
C. CNA and Christensen urea agars and
thioglycollate media
D. Blood, Campy, Mueller–Hinton agars,
and thioglycollate media
A
B. Hektoen, MacConkey, Campy, colistin–nalidixic
acid (CNA) agars
8
Q
- Select the media of choice for recovery of Vibrio
cholerae from a stool specimen.
A. MacConkey agar and thioglycollate media
B. Thiosulfate–citrate–bile–sucrose (TCBS) agar
and alkaline peptone water (APW) broth
C. Blood agar and selenite-F (SEL) broth
D. CNA agar
A
B. Thiosulfate–citrate–bile–sucrose (TCBS) agar
and alkaline peptone water (APW) broth
9
Q
- Colistin–nalidixic acid agar (CNA) is used
primarily for the recovery of:
A. Neisseria species
B. Enterobacteriaceae
C. Pseudomonas aeruginosa
D. Staphylococcus aureus
A
D. Staphylococcus aureus
10
Q
- In the United States, most blood agar plates
are prepared with 5% or 10% red blood cells
(RBCs) obtained from:
A. Sheep
B. Horses
C. Humans
D. Dogs
A
A. Sheep
11
Q
- All of the following are appropriate when
attempting to isolate N. gonorrhoeae from a
genital specimen except:
A. Transport the genital swab in charcoal transport
medium
B. Plate the specimen on modified Thayer–Martin
(MTM) medium
C. Plate the specimen on New York City or
Martin–Lewis agar
D. Culture specimens in ambient oxygen at 37°C
A
D. Culture specimens in ambient oxygen at 37°C
12
Q
- Chocolate agar and modified Thayer–Martin agar
are used for the recovery of:
A. Haemophilus spp. and Neisseria spp., respectively
B. Haemophilus spp. and N. gonorrhoeae,
respectively
C. Neisseria spp. and Streptococcus spp., respectively
D. Streptococcus spp. and Staphylococcus spp.,
respectively
A
B. Haemophilus spp. and N. gonorrhoeae,
respectively
13
Q
- Cycloserine–cefoxitin-fructose agar (CCFA) is
used for the recovery of:
A. Yersinia enterocolitica
B. Yersinia intermedia
C. Clostridium perfringens
D. Clostridium difficile
A
D. Clostridium difficile
14
Q
- Deoxycholate agar (DCA) is useful for the
isolation of:
A. Enterobacteriaceae
B. Enterococcus spp.
C. Staphylococcus spp.
D. Neisseria spp.
A
A. Enterobacteriaceae
15
Q
- Xylose lysine deoxycholate (XLD) agar is a highly
selective medium used for the recovery of which
bacteria?
A. Staphylococcus spp. from normal flora
B. Yersinia spp. that do not grow on Hektoen agar
C. Enterobacteriaceae from gastrointestinal
specimens
D. Streptococcus spp. from stool cultures
A
C. Enterobacteriaceae from gastrointestinal
specimens
16
Q
- A sheep blood agar plate is used as a primary
isolation medium when all of the following
organisms are to be recovered from a wound
specimen except:
A. β-Hemolytic streptococci and coagulase-positive
staphylococci
B. Haemophilus influenzae and Haemophilus
parainfluenzae
C. Proteus spp. and Escherichia coli
D. Pseudomonas spp. and Acinetobacter spp.
A
B. Haemophilus influenzae and Haemophilus
parainfluenzae
17
Q
- Prereduced and vitamin K1-supplemented blood
agar plates are recommended isolation media for:
A. Mycobacterium marinum and Mycobacterium
avium intracellulare
B. Bacteroides, Peptostreptococcus, and Clostridium spp.
C. Proteus spp.
D. Enterococcus spp.
A
B. Bacteroides, Peptostreptococcus, and Clostridium spp.
18
Q
- Which procedure is appropriate for culture
of genital specimens in order to recover
Chlamydia spp.?
A. Inoculate cycloheximide-treated McCoy cells
B. Plate onto blood and chocolate agar
C. Inoculate into thioglycollate (THIO) broth
D. Plate onto modified Thayer–Martin agar within
24 hours
A
A. Inoculate cycloheximide-treated McCoy cells
19
Q
- Specimens for virus culture should be transported
in media containing:
A. Antibiotics and 5% sheep blood
B. Saline and 5% sheep blood
C. 22% bovine albumin
D. Antibiotics and nutrient
A
D. Antibiotics and nutrient
20
Q
- Cerebrospinal fluid (CSF) should be cultured
immediately, but if delayed the specimen
should be:
A. Refrigerated at 4°C to 6°C
B. Frozen at –20°C
C. Stored at room temperature for no longer
than 24 hours
D. Incubated at 37°C and cultured as soon as
possible
A
D. Incubated at 37°C and cultured as soon as
possible
21
Q
- The most sensitive method for the detection
of β-lactamase in bacteria is by the use of:
A. Chromogenic cephalosporin
B. Penicillin
C. Oxidase
D. Chloramphenicol acetyltransferase
A
A. Chromogenic
22
Q
- The breakpoint of an antimicrobial drug refers to:
A. The amount needed to cause bacteriostasis
B. A minimum inhibitory concentration (MIC) of
16 μg/mL or greater
C. A MIC of 64 μg/mL or greater
D. The level of drug that is achievable in serum
A
D. The level of drug that is achievable in serum
23
Q
- Which of the following variables may change the
results of an MIC?
A. Inoculum size
B. Incubation time
C. Growth rate of the bacteria
D. All of these options
A
D. All of these options
24
Q
- According to the Kirby–Bauer standard
antimicrobial susceptibility testing method,
what should be done when interpreting the zone
size of a motile, swarming organism such as a
Proteus species?
A. The swarming area should be ignored
B. The results of the disk diffusion method are
invalid
C. The swarming area should be measured as the
growth boundary
D. The isolate should be retested after diluting to a
0.05 McFarland standard
A
A. The swarming area should be ignored
25
Q
- Which class of antibiotics is used for the treatment
of serious gram-negative infections as well as
infections with Mycobacterium tuberculosis?
A. Cephalosporins
B. Penicillins
C. Tetracyclines
D. Aminoglycosides
A
D. Aminoglycosides
26
Q
- Select the medium best suited for the recovery
of Yersinia enterocolitica from a patient with
gastroenteritis.
A. Hektoen agar
B. Cefsulodin–Irgasan–Novobiocin (CIN) agar
C. Blood agar
D. Eosinmethylene blue agar
A
B. Cefsulodin–Irgasan–Novobiocin (CIN) agar
27
Q
- A suspected case of plague requires which of the
following procedures in order to confirm Yersinia
pestis?
A. Collection of multiple sets of blood cultures
B. Incubation of blood cultures at both 28°C
and 35°C
C. Culture aspirates from bubos to MacConkey
agar at room temperature
D. All of these options
A
D. All of these options
28
Q
- SITUATION: Abdominal pain, fever, vomiting,
and nausea prompted an elderly male to seek
medical attention. A watery stool specimen
producing no fecal leukocytes or erythrocytes
was cultured and grew a predominance of
gram-negative fermentative bacilli. The colonies
were beta-hemolytic on blood agar and cream
colored on MacConkey agar. The colonies were
both oxidase and catalase positive. What is the
most likely identification?
A. Aeromonas hydrophilia
B. Escherichia coli
C. Salmonella spp.
D. Shigella spp.
A
A. Aeromonas hydrophilia
29
Q
- SITUATION: Several attendees of a medical
conference in the Gulf coast area became ill after
frequenting a seafood restaurant. A presumptive
identification of Vibrio cholera was made after
stool specimens from several subjects grew clear
colonies on MacConkey agar and yellow colonies
on TCBS agar. Which key tests would help
eliminate Aeromonas and Plesiomonas spp.?
A. Mannitol fermentation, Na+ requirement
B. Oxidase, motility
C. Oxidase, nitrate
D. Hemolysis on blood agar, catalase
A
A. Mannitol fermentation, Na+ requirement
30
Q
- SITUATION: A group of elementary students
became ill after eating undercooked ground beef
prepared in the school cafeteria. The suspected
pathogen, E. coli serotype 0157:H7, is usually
recovered using which of the following media?
A. XLD agar
B. MacConkey agar
C. MacConkey agar with sorbitol
D. Hektoen agar
A
C. MacConkey agar with sorbitol
