NONFAST, FERM Flashcards
What are the most appropriate screening tests to presumptively differentiate and identify the nonfermentative gram-negative bacilli (NFB) from the Enterobacteriaceae?
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
C. Oxidase, TSI, nitrate reduction, growth on MacConkey agar
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. Oxidase, oxidation-fermentation (OF) glucose (open), OF glucose (sealed), motility, pigment
production
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
D. Mannitol, nitrate reduction, growth at 42°C
Which test group best differentiates Acinetobacter baumannii from P. aeruginosa?
A. Oxidase, motility, NO3 reduction
B. MacConkey growth, 37°C growth, catalase
C. Blood agar growth, oxidase, catalase
D. Oxidase, TSI, MacConkey growth
A. Oxidase, motility, NO3 reduction
In addition to motility, which test best differentiates Acinetobacter spp. and Alcaligenes spp.?
A. TSI
B. Oxidase
C. Catalase
D. Flagellar stain
B. Oxidase
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
C. Oxidase, 42°C growth, and polar tuft of flagella
Which Pseudomonas is usually associated with a lung infection related to cystic fibrosis?
A. P. fluorescens
B. P. aeruginosa
C. P. putida
D. Burkholderia pseudomallei
B. P. aeruginosa
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 in color, 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 alcaligenes
D. Pseudomonas diminuta
A. Pseudomonas stutzeri
Which organism is associated with immunodeficiency syndromes and melioidosis (a glanders-like disease in Southeast Asia and northern Australia)?
A. Pseudomonas aeruginosa
B. Pseudomonas stutzeri
C. Pseudomonas putida
D. Burkholderia pseudomallei
D. Burkholderia pseudomallei
Which biochemical tests are needed 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. TSI, motility, oxidase
A. Pigment on blood agar, oxidase, DNase
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 = +
Glucose OF (open) = +
Pigment = Red (nonfluorescent)
Growth at 42°C = +
Motility = +
Gelatin hydrolysis = +
Arginine dihydrolase = +
Flagella = + (polar, monotrichous)
Which is the most likely organism?
A. Burkholderia pseudomallei
B. Pseudomonas stutzeri
C. Burkholderia cepacia
D. Pseudomonas aeruginosa
D. Pseudomonas aeruginosa
Alcaligenes faecalis (formerly A. odorans) is distinguished from Bordetella bronchiseptica with which test?
A. Urease (rapid)
B. Oxidase
C. Growth on MacConkey agar
D. Motility
A. Urease (rapid)
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. Oxidase, growth on MacConkey agar
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
D. Moraxella lacunata
Cetrimide agar is used as a selective isolation agar for which organism?
A. Acinetobacter spp.
B. Pseudomonas aeruginosa
C. Moraxella spp.
D. Stenotrophomonas maltophilia
B. Pseudomonas aeruginosa
A specimen from a 15-year-old female burn patient was cultured after débridement, and the following results were obtained:
Oxidase = +
Catalase = +
Ornithine decarboxylase = Neg
Arginine dihydrolase = +
Lysine decarboxylase = Neg
Motility = +
Glucose = + for oxidation
(open tube)
Maltose = Neg for oxidation
(open tube)
Penicillin = Resistant
Colistin (Polymixin B) = Susceptible
Aminoglycosides = Susceptible
These results indicate which of the following organisms?
A. Acinetobacter baumannii
B. Moraxella lacunata
C. Pseudomonas aeruginosa
D. Acinetobacter lwoffii
C. Pseudomonas aeruginosa
A yellow pigment-producing organism that is oxidase positive, nonmotile, and does not grow on MacConkey agar is:
A. Acinetobacter baumannii
B. Acinetobacter lwoffii
C. Burkholderia cepacia
D. Chryseobacterium meningosepticum
D. Chryseobacterium meningosepticum
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’s and Kovac’s reagents
C. o-Nitrophenyl-β-D-galactopyranoside
D. Kovac’s reagent
A. Sulfanilic acid and α-naphthylamine
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 42°C = Neg
Nitrate reduction = +
Motility = + (single polar flagellum)
Ornithine decarboxylase = +
The most likely identification is:
A. Shewanella putrefaciens
B. Acinetobacter spp.
C. Pseudomonas aeruginosa
D. Chryseobacterium spp.
A. Shewanella putrefaciens
Chryseobacterium spp. and B. cepacia are easily differentiated by which test?
A. Motility
B. OF glucose
C. Oxidase
D. Cetrimide agar
A. Motility
A 15-year-old female complained of a severe eye irritation after removing her soft-contact lenses. A swab of the infected right eye was obtained by an ophthalmologist, who ordered a culture and sensitivity test. 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 baumannii
B. Pseudomonas aeruginosa
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. P. fluorescens
B. P. putida
C. P. stutzeri
D. P. aeruginosa
D. P. aeruginosa
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. Burkholderia mallei
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.
B. Burkholderia pseudomallei
Cytochrome oxidase-positive, nonfermentative gram-negative bacilli were recovered from the stool of a cystic fibrosis (CF) patient. The isolates produced wet (mucoidy) colonies on blood agar. Which identification is most likely?
A. Acinetobacter spp.
B. Pseudomonas alcaligenes
C. Pseudomonas stutzeri
D. Pseudomonas aeruginosa
D. Pseudomonas aeruginosa
A visitor to South America who returned
with diarrhea is suspected of being infected with V. cholerae. Select the best medium for recovery and identification of this organism.
A. MacConkey agar
B. Blood agar
C. TCBS agar
D. XLD agar
C. TCBS agar
A curved gram-negative rod producing oxidase-positive colonies on blood agar was recovered from a stool culture. Given the following results, what is the most likely identification?
Lysine decarboxylase = +
Indole = +
VP = Neg
Urease = ±
Arginine decarboxylase = Neg
KIA = Alk/Acid
Lactose = Neg
String test = Neg
TCBS agar = Green colonies
A. Vibrio cholerae
B. Vibrio parahaemolyticus
C. Shigella spp.
D. Salmonella spp.
B. Vibrio parahaemolyticus
(V. parahaemolyticus appear as green colonies on TCBS agar, whereas V. cholerae appear as yellow colonies on TCBS.)
A gram-negative S-shaped rod recovered from selective media for Campylobacter species gave the following results:
Catalase = +
Motility = +
Growth at 42°C = +
Grape odor = Neg
Oxidase = +
Hippurate hydrolysis = +
Nalidixic acid = Susceptible
Pigment = Neg
Cephalothin = Resistant
The most likely identification is:
A. Pseudomonas aeruginosa
B. Campylobacter jejuni
C. Campylobacter fetus
D. Pseudomonas putida
B. Campylobacter jejuni
Which atmospheric condition is needed to recover Campylobacter spp. from specimens inoculated onto a Campy-selective agar at 35°C-37°C
and 42°C?
A. 5% O2, 10% CO2, and 85% N2
B. 20% O2, 10% CO2, and 70% N2
C. 20% O2, 20% CO2, and 60% N2
D. 20% O2, 5% CO2, and 75% N2
A. 5% O2, 10% CO2, and 85% N2
Which group of tests best differentiates Helicobacter pylori from C. jejuni?
A. Catalase, oxidase, and Gram stain
B. Catalase, oxidase, and nalidixic acid sensitivity
C. Catalase, oxidase, and cephalothin sensitivity
D. Urease, nitrate, and hippurate hydrolysis
D. Urease, nitrate, and hippurate hydrolysis
Which of the following tests should be done first in order to differentiate Aeromonas spp. from the Enterobacteriaceae?
A. Urease
B. OF glucose
C. Oxidase
D. Catalase
C. Oxidase
Which is the best rapid test to differentiate Plesiomonas shigelloides from a Shigella species on selective enteric agar?
A. Oxidase
B. Indole
C. TSI
D. Urease
A. Oxidase
Which are the best two tests to differentiate A. hydrophilia from P. shigelloides?
A. Oxidase and motility
B. DNase and VP
C. Indole and lysine decarboxylase
D. Growth on MacConkey and blood agar
B. DNase and VP
Which genus (in which most species are oxidase and catalase positive) of small gram-negative coccobacilli is associated mainly with animals but may cause endocarditis, bacteremia, as well as wound and dental infections in humans?
A. Actinobacillus
B. Pseudomonas
C. Campylobacter
D. Vibrio
A. Actinobacillus
Which of the following tests may be used to differentiate Cardiobacterium hominis from Actinobacillus spp.?
A. Gram stain
B. Indole
C. Anaerobic incubation
D. Oxidase
B. Indole
A mixture of slender gram-negative rods and coccobacilli with rounded ends was recovered from blood cultures following a patient’s root canal surgery. Given the following results after 48 hours, what is the most likely organism?
Catalase = Neg
Urease = Neg
Oxidase = +
Indole = Neg
Ornithine decarboxylase = +
Lysine decarboxylase = +
X and V requirement = Neg
Carbohydrates = Neg
(no acid produced)
Growth on blood and chocolate agar = + (with pitting of agar)
Growth on MacConkey agar = Neg
A. Eikenella corrodens
B. Actinobacillus spp.
C. Cardiobacterium hominis
D. Proteus spp.
A. Eikenella corrodens
Kingella kingae can best be differentiated from Eikenella corrodens using which medium?
A. Sheep blood agar
B. Chocolate agar
C. MacConkey agar
D. XLD agar
A. Sheep blood agar
Kingella kingae is usually associated with which type of infection?
A. Middle ear
B. Endocarditis
C. Meningitis
D. Urogenital
B. Endocarditis
Cultures obtained from a dog bite wound produced yellow, tan, and slightly pink colonies on blood and chocolate agar with a margin of fingerlike projections appearing as a film around the colonies. Given the following results at 24 hours, which is the most likely organism?
Oxidase = +
Growth on MacConkey agar = Neg
Catalase = +
Motility = Neg
A. Actinobacillus spp.
B. Eikenella spp.
C. Capnocytophaga spp.
D. Pseudomonas spp.
C. Capnocytophaga spp.
Smooth gray colonies showing no hemolysis are recovered from an infected cat scratch on blood
and chocolate agar but fail to grow on MacConkey agar. The organisms are gram-negative pleomorphic rods that are both catalase and oxidase positive
and strongly indole positive. The most likely organism is:
A. Capnocytophaga spp.
B. Pasteurella spp.
C. Proteus spp.
D. Pseudomonas spp.
B. Pasteurella spp.
Which media should be used to recover Bordetella pertussis from a nasopharyngeal specimen?
A. Chocolate agar
B. Blood agar
C. MacConkey agar
D. Bordet-Gengou agar
D. Bordet-Gengou agar
Which medium is recommended for the recovery of Brucella spp. from blood and bone marrow specimens?
A. Biphasic Castenada bottles with Brucella broth
B. Blood culture bottles with Brucella broth
C. Bordet-Gengou agar plates and THIO broth
D. Blood culture bottles with THIO broth
A. Biphasic Castenada bottles with Brucella broth
In addition to CO2 requirements and biochemical characteristics, Brucella melitensis and Brucella abortus are differentiated by growth on media containing which two dyes?
A. Basic fuchsin and thionin
B. Methylene blue and crystal violet
C. Carbol fuchsin and iodine
D. Safranin and methylene blue
A. Basic fuchsin and thionin
Which of the following amino acids are required for growth of Francisella tularensis?
A. Leucine and ornithine
B. Arginine and lysine
C. Cysteine and cystine
D. Histidine and tryptophan
C. Cysteine and cystine
Which medium is best for recovery of Legionella pneumophila from clinical specimens?
A. Chocolate agar
B. Bordet-Gengou agar
C. New yeast extract agar
D. Buffered charcoal-yeast extract (CYE) agar
D. Buffered charcoal-yeast extract (CYE) agar
Haemophilus influenzae causes ocular infections (pinkeye) and requires X and V factors in the primary medium for growth. The subspecies Haemophilus influenza (biogroup) aegyptius can further be identified and differentiated by which two tests?
A. Indole and xylose
B. Glucose and urease
C. Oxidase and catalase
D. ALA test and oxidase
A. Indole and xylose
Haemophilus species that require the V factor (NAD) are easily recovered on which primary agar plate?
A. Blood agar made with sheep red cells
B. Blood agar made with horse red cells
C. Chocolate agar
D. Xylose agar
C. Chocolate agar
Which of the following products is responsible for satellite growth of Haemophilus spp. around colonies of Staphylococcus and Neisseria spp. on sheep blood agar?
A. NAD
B. Hemin
C. Indole
D. Oxidase
A. NAD
Which of the following plates should be used in order to identify Haemophilus haemolyticus and Haemophilus parahaemolyticus?
A. Sheep blood agar and chocolate agar
B. Horse blood agar and Mueller-Hinton agar with X and V strips
C. Brain-heart infusion agar with sheep red cells added
D. Chocolate agar and Mueller-Hinton agar with X factor added
B. Horse blood agar and Mueller-Hinton agar with X and V strips
The majority of Haemophilus influenzae infections are caused by which of the following capsular serotypes?
A. a
B. b
C. c
D. d
B. b
Which Haemophilus species is generally associated with endocarditis?
A. H. influenzae
B. H. ducreyi
C. H. aphrophilus
D. H. haemolyticus
C. H. aphrophilus
Which Haemophilus species is difficult to isolate and recover from genital ulcers and swollen lymph nodes?
A. H. aphrophilus
B. H. ducreyi
C. H. haemolyticus
D. H. parahaemolyticus
B. H. ducreyi
Which of the following is a characteristic of strains of Haemophilus influenzae that are resistant to ampicillin?
A. Production of β-lactamase enzymes
B. Hydrolysis of chloramphenicol
C. Hydrolysis of urea
D. All of these options
A. Production of β-lactamase enzymes
A small, gram-negative coccobacillus recovered from the CSF of a 2-year-old child gave the following results:
Indole = +
X requirement = +
Urease = +
Sucrose = Neg
Glucose = + (acid)
V requirement = +
Lactose = Neg
Hemolysis = Neg
Which is the most likely identification?
A. Haemophilus parainfluenzae
B. Haemophilus influenzae
C. Haemophilus ducreyi
D. Haemophilus aphrophilus
B. Haemophilus influenzae
The δ-ALA test (for porphyrins) is a confirmatory procedure for which test used for identification of Haemophilus species?
A. X factor requirement
B. V factor requirement
C. Urease production
D. Indole production
A. X factor requirement
An elderly woman who cared for several domestic cats was hospitalized with suspected cat-scratch disease (CSD). Blood cultures appeared negative, but a small, slightly curved pleomorphic gram-negative bacillus grew on BHI agar (brain, heart infusion agar with 5% horse or rabbit blood). What is the most likely identification?
A. Bartonella spp.
B. Brucella spp.
C. Kingella spp.
D. Haemophilus spp.
A. Bartonella spp.
A 5-year-old nonimmunized male with a persistent cough, fever, and flulike symptoms was admitted to the hospital. Nasopharyngeal swabs were cultured on 15% blood, chocolate, Bordet-Genjou, and Regan-Lowe (with 10% charcoal) agars. All media grew a gram-negative coccobacillus. Carbohydrate and biochemical tests were negative. What is the most likely identification?
A. Haemophilus influenza
B. Bordetella pertussis
C. Haemophilus parainfluenzae
D. Bordetella bronchiseptica
B. Bordetella pertussis
A 29-year-old male who often hunted rabbits
and spent a lot of time in the woods was admitted to the hospital with skin ulcers on his upper extremities. At 48 hours, a small coccobacillus was recovered from the aerobic blood culture bottle only. The organism stained poorly with Gram stain, but did stain with acridine orange. Cultures taken from the ulcers did not grow on primary media. What is the most likely identification?
A. Pseudomonas aeruginosa
B. Pseudomonas fluorescens
C. Chryseobacterium spp.
D. Francisella tularensis
D. Francisella tularensis
A neonate was readmitted to the hospital with
a diagnosis of meningitis. The CSF revealed gram-negative straight rods. At 24 hours, the organism grew on 5% sheep blood and chocolate agars displaying a yellow pigment. On MacConkey agar, it appeared as a non-lactose fermenter. Colonies were oxidase, DNase, and gelatinase positive, and oxidized glucose and mannitol.
What is the most likely identification?
A. Haemophilus influenza
B. Chryseobacterium meningosepticum
C. Stenotrophomonas maltophilia
D. Acinetobacter baumannii
B. Chryseobacterium meningosepticum
A 46-year-old dog warden was admitted to the hospital with several puncture bite wounds encountered while wrangling with a stray dog. Culture at 48 hours produced small yellow colonies on 5% sheep blood and chocolate agars in 10% CO2, but no growth on MacConkey agar. Gram stain showed gram-negative curved, fusiform rods. Colonies were oxidase and catalase positive. What is the most likely identification?
A. Capnocytophaga canimorsus
B. Francisella tularensis
C. Legionella pneumophila
D. Pseudomonas aeruginosa
A. Capnocytophaga canimorsus
The HACEK group of organisms (Haemophilus aphrophilus, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella spp.) are all known for which type of infection?
A. Urinary tract
B. Endocarditis
C. Pharyngitis
D. Tonsillitis
B. Endocarditis
A suspected case of Legionnaires’ disease was noted on the request form for a culture and sensitivity ordered on a sputum sample. The patient was a 70-year-old male who presented with a positive serological test for Legionella spp. What is the most efficient way to confirm the infection using the submitted sample?
A. Culture the sputum on MacConkey agar
B. Gram stain of the sputum
C. Acid-fast staining
D. Direct immunofluorescent microscopy
D. Direct immunofluorescent microscopy
