MICROBIO - Chapter 8.3 Flashcards

1
Q

What are the most appropriate screening tests to presumptively differentiate and identify the nonfermentative gram-negative bacilli (NFB) from the Enterobacteriaceae species?
A. Catalase, decarboxylation of arginine, growth on blood agar
B. Motility, urease, morphology on blood agar
C. Oxidase, TSI, nitrate reduction, growth on MacConkey agar
D. Oxidase, indole, and growth on blood agar

A

C. Oxidase, TSI, nitrate reduction, growth on MacConkey agar

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2
Q

Presumptive tests used for identification of the Pseudomonas spp. are:
A. Oxidase, oxidation–fermentation (OF) glucose (open), OF glucose (sealed), motility, pigment production
B. Growth on blood agar plate (BAP) and eosin–methylene blue (EMB) agars, lysine decarboxylation, catalase
C. Growth on MacConkey, EMB, and XLD agars and motility
D. Growth on mannitol salt agar and flagellar stain

A

A. Oxidase, oxidation–fermentation (OF) glucose (open), OF glucose (sealed), motility, pigment production

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3
Q

Which tests are most appropriate to differentiate between Pseudomonas aeruginosa and Pseudomonas putida?
A. Oxidase, motility, pyoverdin
B. Oxidase, motility, lactose
C. Oxidase, ONPG, DNase
D. Mannitol, nitrate reduction, growth at 42°C

A

D. Mannitol, nitrate reduction, growth at 42°C

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4
Q

Which test group best differentiates Acinetobacter spp. from P. aeruginosa?
A. Oxidase, motility, nitrate reduction
B. MacConkey growth, 37°C growth, catalase
C. Blood agar growth, oxidase, catalase
D. Oxidase, TSI, MacConkey growth

A

A. Oxidase, motility, nitrate reduction

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5
Q

In addition to motility, which test best differentiates Acinetobacter spp. and Alcaligenes faecalis?
A. Triple sugar iron agar
B. Oxidase
C. Urease
D. Flagellar stain

A

B. Oxidase

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6
Q

The most noted differences between P. aeruginosa and Stenotrophomonas maltophilia are:
A. Oxidase, catalase, and TSI
B. Oxidase, catalase, and ONPG
C. Oxidase, 42°C growth, and polar tuft of flagella
D. Catalase, TSI, and pigment

A

C. Oxidase, 42°C growth, and polar tuft of flagella

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7
Q

Which nonfermentative bacillus is usually associated with a lung infection related to cystic fibrosis (CF)?
A. Pseudomonas fluorescens
B. Pseudomonas aeruginosa
C. Pseudomonas putida
D. Burkholderia pseudomallei

A

B. Pseudomonas aeruginosa

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8
Q

A nonfermenter recovered from an eye wound is oxidase positive, motile with polar monotrichous flagella, and grows at 42°C. Colonies are dry, wrinkled or smooth, buff to light brown, and are difficult to remove from the agar. In which DNA homology group should this organism be placed?
A. Pseudomonas stutzeri
B. Pseudomonas fluorescens
C. Pseudomonas putida
D. Burkholderia pseudomallei

A

A. Pseudomonas stutzeri

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9
Q

Which organism is associated with immunodeficiency syndromes and melioidosis (a glanders-like disease prevalent in Southeast Asia and northern Australia)?
A. Pseudomonas aeruginosa
B. Pseudomonas stutzeri
C. Pseudomonas putida
D. Burkholderia pseudomallei

A

D. Burkholderia pseudomallei

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10
Q

Which characteristics/biochemical tests are used to differentiate Burkholderia cepacia from S. maltophilia?
A. Pigment on blood agar, oxidase, DNase
B. Pigment on MacConkey agar, flagellar stain, motility
C. Glucose, maltose, lysine decarboxylase
D. Triple-sugar iron agar, motility, oxidase

A

A. Pigment on blood agar, oxidase, DNase

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11
Q

The following results were obtained from a pure culture of gram-negative rods recovered from the pulmonary secretions of a 10-year-old cystic fibrosis patient with pneumonia:

Oxidase = +
Glu OF (open) = +
Pigment = red
Growth at 42C = +
Motility = +
Gelatin hydrolysis = +
Arginine dihydrolase = + (nonfluorescent)
Flagella = + (polar, monotrichous)

Which is the most likely organism?
A. Burkholderia pseudomallei
B. Pseudomonas stutzeri
C. Burkholderia cepacia
D. Pseudomonas aeruginosa

A

D. Pseudomonas aeruginosa

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12
Q

Alcaligenes faecalis (formerly A. odorans) is distinguished from Bordetella bronchiseptica with which test?

A

Urease (rapid)

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13
Q

Chryseobacterium spp. are easily distinguished from Acinetobacter spp. by which of the following two tests?
A. Oxidase, growth on MacConkey agar
B. Oxidase and OF (glucose)
C. TSI and urea hydrolysis
D. TSI and VP

A

A. Oxidase, growth on MacConkey agar

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14
Q

A gram-negative coccobacillus was recovered on chocolate agar from the CSF of an immunosuppressed patient. The organism was nonmotile and positive for indophenol oxidase but failed to grow on MacConkey agar. The organism was highly susceptible to penicillin. The most probable identification is:
A. Acinetobacter spp.
B. Pseudomonas aeruginosa
C. Pseudomonas stutzeri
D. Moraxella lacunata

A

D. Moraxella lacunata

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15
Q

Cetrimide agar is used as a selective isolation agar for which organism?
A. Acinetobacter spp.
B. Pseudomonas aeruginosa
C. Moraxella spp.
D. Stenotrophomonas maltophilia

A

B. Pseudomonas aeruginosa

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16
Q

A specimen from a 15-year-old female burn patient was cultured after débridement, and the following results were obtained:

Oxidase = +
Catalase = +
Ornithine decarboxylase= -
Arginine dihydrolase = +
Penicillin = Resistant
Colistin (Polymixin B) = Susceptible
Lysine decarboxylase = -
Motility = +
Glucose = + for oxidation (open tube)
Maltose = - for oxidation (open tube)
Aminoglycosides (susceptible)

These results indicate which of the following organisms?
A. Acinetobacter spp.
B. Moraxella lacunata
C. Pseudomonas aeruginosa
D. Alcaligenes spp.

A

C. Pseudomonas aeruginosa

17
Q

A yellow pigment–producing organism, growing on chocolate agar, testing oxidase positive, nonmotile and does not grow on MacConkey agar was recovered from the blood of a neonate. What is the most likely organism?
A. Acinetobacter spp.
B. Pseudomonas aeruginosa
C. Burkholderia cepacia
D. Elizabethkingia (formerly Chryseobacterium) meningosepticum

A

D. Elizabethkingia (formerly Chryseobacterium) meningosepticum

18
Q

Which reagent(s) is (are) used to develop the red color indicative of a positive reaction in the nitrate reduction test?
A. Sulfanilic acid and α-naphthylamine
B. Ehrlich and Kovac reagents
C. o-Nitrophenyl-β-D-galactopyranoside
D. Kovac reagent

A

A. Sulfanilic acid and α-naphthylamine

19
Q

A culture from an intra-abdominal abscess produced orange-tan colonies on blood agar that gave the following results:

Oxidase = +
KIA = Alk/Alk (H2S) +
DNase = +
Growth at 42C = -
Nitrate reduction = +
Motility = + (single polar flagellum)
Ornithine decarboxylase = +
MAC = NLF

The most likely identification is:
A. Shewanella putrefaciens
B. Acinetobacter spp.
C. Pseudomonas aeruginosa
D. Chryseobacterium spp.

A

A. Shewanella putrefaciens

20
Q

Chryseobacterium spp. and B. cepacia are easily differentiated by which test?
A. Motility
B. OF glucose
C. Oxidase
D. Cetrimide agar

A

A. Motility

21
Q

A 15-year-old female complained of a severe eye irritation after removing her soft contact lenses. A swab specimen of the infected right eye was obtained by an ophthalmologist, who ordered culture and sensitivity testing. The culture was plated on blood agar and MacConkey agar. At 24 hours, growth of a gram-negative rod that tested positive for cytochrome oxidase was noted. The Mueller-Hinton sensitivity plate showed a bluish-green “lawn” of growth that proved highly resistant to most of the antibiotics tested except amikacin, tobramycin, and ciprofloxacin. What is the most likely identification?
A. Burkholderia cepacia
B. Pseudomonas aeruginosa
C. Stenotrophomonas maltophilia
D. Acinetobacter spp.

A

B. Pseudomonas aeruginosa

22
Q

Which of the listed Pseudomonas spp. is associated with the following virulence factors: exotoxin A, endotoxins, proteolytic enzymes, antimicrobial resistance, and production of alginate?
A. Pseudomonas fluorescens
B. Pseudomonas putida
C. Pseudomonas stutzeri
D. Pseudomonas aeruginosa

A

D. Pseudomonas aeruginosa

23
Q

A 20-year-old horse groomer exhibited a “glanders-like” infection. His history indicated he had suffered several open wounds on his hands 2 weeks before the swelling of his lymph nodes. A gram-negative rod was recovered from a blood culture that grew well on blood and MacConkey agars. Most of the biochemical tests were negative, including the cytochrome oxidase test. What is the most likely identification?
A. Burkholderia mallei
B. Pseudomonas aeruginosa
C. Pseudomonas stutzeri
D. Burkholderia pseudomallei

A

A. Burkholderia mallei

24
Q

A Vietnam War veteran presented with a “glanders-like” infection (melioidosis). Several blood cultures produced gram-negative rods that were positive for cytochrome oxidase, oxidized glucose and xylose, and grew at 42°C. What is the most likely organism?
A. Stenotrophomonas maltophilia
B. Burkholderia pseudomallei
C. Pseudomonas aeruginosa
D. Acinetobacter spp.

A

B. Burkholderia pseudomallei

25
Q

Cytochrome oxidase-positive, nonfermentative gram-negative bacilli were recovered from the stool of a patient with CF. The isolates produced wet (mucoidy) light blue colonies on tryptic soy agar. Which identification is most likely?
A. Acinetobacter spp.
B. Pseudomonas putida
C. Pseudomonas stutzeri
D. Pseudomonas aeruginosa

A

D. Pseudomonas aeruginosa

26
Q

Several postoperative hospitalized patients were colonized with gram-negative coccobacilli growing on MacConkey agar. Specimens were obtained from blood, urine, and wound sites. Testing revealed oxidase negative, nonmotile organisms. Which of the following is the most likely cause of the nosocomial infections?
A. Acinetobacter spp.
B. Pseudomonas aeruginosa
C. Burkholderia cepacia
D. Pseudomonas putida

A

A. Acinetobacter spp.

27
Q

A nosocomial infection involving an 80-year-old female patient, recovering from pneumonia, produced many oxidase-negative colonies on MacConkey agar. Further testing results are:

Motility = +
Glucose = +
Maltose = +
Resistant to most aminoglycosides
Resistant to most beta-lactams

The most likely identification is:
A. Acinetobacter spp.
B. Stenotrophomonas maltophilia
C. Pseudomonas aeruginosa
D. Burkholderia gladioli

A

B. Stenotrophomonas maltophilia