Final Finalsss Flashcards
A physician inquiry about repeated sputum specimens, negative on routine bacterial culture, that are reported to contain only normal oropharyngeal flora on routine bacterial culture. The patient is a 67-year- old man who smokes 15 to 20 cigarettes a day and persistent cough, malaise, and a fever of 102-105°F. Empiric antimicrobial therapy and the cough and fever persist. The most recent direct Gram’s stain of sputum shows 3+ PMNs, mucus present, and rare epithelial cells. A likely etiologic agent is?
a. Haemophilus influenzae
b. Legionella pneumophila
c. Pseudomonas aeruginosa
d. Streptococcus pneumoniae
Legionella pneumophila
Anaerobic gram-positive bacilli with subterminal spores were recovered from several blood
cultures obtained from a patient diagnosed with a malignancy of the colon. The following
results were recorded: Indole = Neg Urease = Neg Lipase = Neg Catalase = Neg Lecithinase
= Neg Growth on blood agar = Swarming colonies What is the correct identification?
a. Clostridium sordellii
b. Clostridium septicum
c. Clostridium perfringens
d. Propionibacterium acnes
Clostridium septicum
Which of the following is NOT true about Chlamydia pneumoniae?
I. Common agent of lower respiratory tract infection
II. Humans become infected from animal reservoirs.
III. High risk for patients with nerve ending damages
IV. Hep 2 cell culture and Macro-immunofluorescence
a. II, IV
b. I, III
c. II, III
d. I, IV
I, III
Gram negative coccobacilli was isolated from ear discharge after 48 hours of incubation
on Horse Blood agar plate. The isolates were positive on ornithine and Urea tests. What
most likely is the organism?
a. H. Parainfluenzae Biotype II
b. H. Haemolyticus Biotype I
c. H. influenzae Biotype I
d. H. parahaemolyticus Biotype IV
e. H. ducreyi Biotype III
H. influenzae Biotype I
Anaerobic gram-positive, spore-forming bacilli were recovered from the feces of a
chemotherapy patient with severe diarrhea. The patient had undergone antibiotic therapy 1
week prior. The fecal culture produced growth only on the CCFA plate. No aerobic growth
of normal flora was seen after 48 hours.
The following results were noted:
Kanamycin = Sensitive Vancomycin = Sensitive Colistin = Resistant
Lecithinase = negative Lipase = negative Nitrate = negative
Indole = colorless ring Urease = orange Catalase = Neg
Spores = positive
Colonial morphology
CCFA agar = Growth of yellow, “ground-glass” colonies that fluoresce chartreuse (yellow-green)
A. Clostridium sordellii
B. Clostridium tetani
C. Clostridium difficile
D. Clostridium perfringens
Clostridium perfringens
Egg yolk agar is used to detect which enzyme produced by Clostridium species?
a. β-Lactamase
b. Lecithinase
c. Catalase
d. Oxidase
Lecithinase
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. Oxidase
b. Hemin
c. Indole
d. NAD
NAD
Which mechanism is responsible for botulism in infants caused by Clostridium botulinum?
a. Virulence of the organism
b. Ingestion of preformed toxin in food
c. Lipase activity of the organism
d. Ingestion of spores in food or liquid
Ingestion of spores in food or liquid
Francisella tularensis is the bacterium that causes tularemia, a disease not uncommonly
seen in hunters. Which of the following statements best characterizes this bacterium?
A. It produces at least one protein toxin consisting of two subunits. A and R, that causes severe spasmodic
cough usually in children.
B. It secretes erythrogenic toxin that causes the characteristic signs of scarlet fever. Strep. pyogenes
C. It secretes exotoxin that has been called “verotoxin” and ‘Shiga-like toxin”; Infection is mediated by a specific attachment to mucosal Membranes.
D. It requires cysteine for growth
E. It produces toxin that blocks protein synthesis in an infected cell and carries a lytic bacteriophage that
produces the genetic information for toxin production.
It requires cysteine for growth
Anaerobic gram-positive diphtheroids , non-spore formers were cultured from two separate
blood culture bottles (at 5 days) obtained from a 25-year-old patient admitted to the
hospital with dehydration, diarrhea, and other flulike symptoms. Four other blood culture
bottles did not grow any organisms at 7 days and were discarded. The following results
were obtained from the recovered anaerobe: positive in Indole, Nitrate, and Catalase test.
Susceptible in Susceptible in kanamycin and vancomycin while resistant in Colistin. What
is the correct identification?
a. Eubacterium lentum
b. Actinomyces spp.
c. Propionibacterium acnes
d. Peptostreptococcus spp.
Propionibacterium acnes
All of the following genera are anaerobic cocci that stain gram positive except:
a. Peptostreptococcus spp.
b. Streptococcus spp.
c. Peptococcus spp.
d. Veillonella spp.
Veillonella spp.
Identify the Haemophilus species:
Requirement for X factor: positive
Requirement for V factor. positive
Hemolysis: negative
ALA: negative
Fermentation of glucose: positive
Fermentation of sucrose: negative
Fermentation of lactose: negative
Fermentation of fructose: negative
A. H. influenzae
B. H. parahaemolyticus
C. H. ducreyi
D. H. Parainfluenzae
E. H. Haemolyticus
H. influenzae
Detection of antibody against cardiolipin is useful for the diagnosis of which of the
following disease?
A. Relapsing fever
B. Lyme disease
C. Leptospirosis
D. Syphilis
Syphilis
Haemophilus influenzae causes ocular infections 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. Oxidase and catalase
c. ALA test and oxidase
d. Glucose and urease
Indole and xylose
The causative agent of endemic or murine typhus is
A. Rickettsia conorii
B. Rickettsia typhi
C. Rickettsia akari
D. Rickettsia prowazekii
Rickettsia typhi
Rocky Mountain Spotted fever is transmitted by the bite of a tick infected with.
a. Rickettsia prowazekii
b. Rickettsia conorii
c. Rickettsia rickettsii
d. Rickettsia akari
Rickettsia rickettsii
Which gram-negative bacilli produce black pigment and brick red fluorescence when
exposed to an ultraviolet light source?
a. Bacteroides spp. and Fusobacterium spp.
b. Porphyromonas spp. and Prevotella spp.
c. Fusobacterium spp. and Actinomyces spp.
d. All of these options
Porphyromonas spp. and Prevotella spp.
A gram-negative coccobacillus was isolated from upper respiratory tract sections with
these biochemical reactions: Hemin factor: no growth; NAD factor with growth, with red
end-colored in fermentation of mannose and mannitol, and colorless at ONPG
a. H. Parainfluenzae
b. H. influenzae
c. H. ducreyi
d. H. parahaemolyticus
e. H. Haemolyticus
H. parahaemolyticus
The diagnosis of Lyme disease can be made by:
A. silver impregnation techniques to demonstrate spirochete in tissue
B. serological demonstration of antibody in patient’s serum using enzyme immunoassay
C. growth on blood and chocolate agar
D. both A and B
E. all of the above
all of the above
rationale: in stages I and II of Lyme disease, EIA testing is performed on serum for antibodies. PCR testing and culture of Borrelia spp. are performed on a skin biopsy. In stage III, synovial fluid, skin biopsy, and CSF are tested for Borrelia spp. by PCR
The mild type of typhus fever that is caused by recrudescence of an initial attack of
epidemic typhus is known as:
a. Brill-Zinsser disease
b. Q fever
c. Tsutsugamushi disease
d. Relapsing fever
Brill-Zinsser disease
Identify the following bacterium and specimen pairing that is mismatched (specimen not
appropriate for isolation).
a. Chlamydia trachomatis: first voided urine
b. Chlamydia psittaci: fecal swab
c. Chlamydia trachomatis: endocervical swab
d. Chlamydia pneumonia: throat swab or sputum
Chlamydia psittaci: fecal swab
The following characteristics of an obligate anaerobic gram-negative bacilli best describe
which of the listed genera? Gram stain: long, slender rods with pointed ends colonial
appearance: dry bread crumbs or “fried-egg” appearance Penicillin 2-unit disk test:
Susceptible
a. Bacteroides spp.
b. Fusobacterium spp.
c. Porphyromonas spp.
d. Prevotella spp
Fusobacterium spp.
An elderly woman who cared for several domestic cats was hospitalized with suspected
cat-scratch disease. Blood cultures appeared negative, but a small, slightly curved
pleomorphic gram-negative bacillus grew on BHI agar. What is the most likely
identification?
a. Haemophilus spp.
b. Bartonella spp.
c. Kingella spp.
d. Brucella spp.
Bartonella spp.
Obligate anaerobic gram-negative bacilli that do not form spores grow well in 20% bile and
are resistant to penicillin 2-unit disks are most likely:
a. Prevotella spp.
b. Bacteroides spp.
c. Fusobacterium spp.
d. Porphyromonas spp.
Bacteroides spp.
The δ-ALA test is a confirmatory procedure for which test used for identification of
Haemophilus species?
a. V factor requirement
b. Urease production
c. Indole production
d. X factor requirement
X factor requirement
A Porphyromonas spp.
a. Bacteroides spp.
b. Prevotella spp.
c. Fusobacterium spp
Fusobacterium spp
The majority of Haemophilus influenzae infections are caused by which of the following
capsular serotypes?
a. b
b. a
c. c
d. d
b capsular serotypes
Borrelia burgdorferi, a spirochete transmitted by Ixodes dammini and the etiologic agent
of?
a. Q fever
b. Lyme disease
c. Relapsing fever
d. Rat-like fever
Lyme disease
A gram positive, spore-forming bacillus growing on blood agar anaerobically produces a
double zone of beta hemolysis and is positive for lecithinase. What is the presumptive
identification of this isolate?
a. Clostridium difficile
b. Bacteroides urealyticus
c. Bacteroides fragilis
d. Clostridium perfringens
Clostridium perfringens
During the first week of leptospirosis, the most reliable way to detect the presence of the
causative agent is by the direct
I. culturing blood
II. culturing urine
III. Examination of blood
IV. Examination of CSF
A. I, III
B. IV only
C. II
D. I only
I only
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. Brain–heart infusion agar with sheep red cells added
c. Horse blood agar and Mueller–Hinton agar with X and V strips
d. Chocolate agar and Mueller–Hinton agar with X factor added
Horse blood agar and Mueller–Hinton agar with X and V strips
A direct smear of a specimen for aerobic and anaerobic culture revealed the presence of
gram positive rods. A blood agar plate was inoculated and incubated in an aerobic
environment and in a clinical laboratorian saw that the methylene blue strip was blue.
Growth was observed in both the aerobic and anaerobic plate. Which of the following
statements is most likely true?
a. The isolate is most likely a strict aerobe
b. The isolate is most likely facultative anaerobe
c. The isolate is most likely a strict anaerobe
d. Cannot be determined; the methylene blue was blue and this indicates that oxygen is present in the anaerobic jar
Cannot be determined; the methylene blue was blue and this indicates that oxygen is present in the anaerobic jar
Which of the following is not correct about spirochetes?
I. Motility is via axial filaments
II. They are visualized both in dark field and phase optics
III. Spirochetes are gram positive
IV. Those humans with disease are 0.1-0.5 um in diameter and 5-30um in length
A. II, IV
B. II, III
C. III, IV
D.
I, III
III, IV
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–Gengou, and Regan–Lowe (with 10% charcoal) agars. All media grew a gramnegative coccobacillus. Carbohydrate and biochemical tests were negative. What is the
most likely identification?
a. Bordetella bronchiseptica
b. Bordetella pertussis
c. Haemophilus influenza
d. Haemophilus parainfluenzae
Bordetella pertussis
The gram-positive non–spore-forming anaerobic rods most frequently recovered from
blood cultures as a contaminant are:
a. Propionibacterium acnes
b. Veillonella parvula
c. Staphylococcus intermedius
d. Clostridium perfringens
Propionibacterium acnes
Which Haemophilus species is difficult to isolate and recover from genital ulcers and
swollen lymph nodes?
a. H. haemolyticus
b. H. ducreyi
c. H. parahaemolyticus
d. H. aphrophilus
H. ducreyi
A small, gram-negative coccobacillus recovered from the blood samples of a 2-year-old
child gave the following results:
Indole = red ring Glucose = positive X requirement = no growth
V requirement = with growth Nitrate reduction= red Lactose = Negative
Sucrose = positive ALA= reddish orange Hemolysis= Negative
Which is the most likely identification?
A. Haemophilus influenzae
B. Haemophilus ducreyi
C. Haemophilus parahaemolyticus
D. Haemophilus parainfluenzae
Haemophilus parainfluenzae
A gram-negative S-shaped rod recovered from selective media for Campylobacter species
gave the following results:
Catalase = with effervescence Oxidase = purple Motility = turbid
Hippurate hydrolysis = purple Growth at 42°C = positive
Growth at 25C = negative Nalidixic acid = Susceptible
Pigment = Negative Cephalothin = Resistant
Urease: orange
The most likely identification is:
a. Campylobacter fetus
b. Campylobacter jejuni
c. Pseudomonas putida
d. Pseudomonas aeruginosa
Campylobacter jejuni
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
Urease, nitrate, and hippurate hydrolysis
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
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
Indole
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
Sheep blood agar
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
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
Biphasic Castenada bottles with Brucella broth
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
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
Buffered charcoal–yeast extract (CYE) agar
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
Chocolate agar
Haemophilus influenzae causes ocular infections
(pinkeye) and requires X and V factors in the
primary medium for growth. Te 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
Indole and xylose
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
NAD
Which Haemophilus species is generally associated
with endocarditis?
A. H. influenzae
B. H. ducreyi
C. H. aphrophilus
D. H. haemolyticus
H. aphrophilus
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
Production of β-lactamase enzymes
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. Te 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
Francisella tularensis
A suspected case of Legionnaires’ disease was
noted on the request form for a culture and
sensitivity ordered on a sputum sample. Te
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
Direct immunofluorescent microscopy
Obligate anaerobes, facultative anaerobes, and
microaerophiles are terms referring to bacteria
that require:
A. Increased nitrogen
B. Decreased CO2
C. Increased O2
D. Decreased O2
Decreased O2
Which of the following is the medium of choice
for the selective recovery of gram-negative
anaerobes?
A. Kanamycin–vancomycin (KV) agar
B. Phenylethyl alcohol (PEA) agar
C. Cycloserine–cefoxitin–fructose agar (CCFA)
D. THIO broth
Kanamycin–vancomycin (KV) agar
Anaerobic bacteria are routinely isolated from
all of the following types of infections except:
A. Lung abscesses
B. Brain abscesses
C. Dental infections
D. Urinary tract infections
Urinary tract infections
Which of the following organisms will display
lipase activity on egg yolk agar?
A. Clostridium botulinum
B. Clostridium sporogenes
C. Clostridium novyi (A)
D. All of these options
All of these options
Which spore type and location is found on
Clostridium tetani?
A. Round, terminal spores
B. Round, subterminal spores
C. Ovoid, subterminal spores
D. Ovoid, terminal spores
Round, terminal spores
Te classic form of foodborne botulism is
characterized by the ingestion of:
A. Spores in food
B. Preformed toxin in food
C. Toxin H
D. All of these options
Preformed toxin in food
Which Clostridium spp. causes pseudomembranous
colitis or antibiotic-associated colitis?
A. C. ramosum
B. C. difficile
C. C. perfringens
D. C. sporogenes
C. difficile
Which Bacteroides spp. is noted for “pitting” of
the agar and is sensitive to penicillin 2-unit disks?
A. B. vulgatus
B. B. ovatus
C. B. thetaiotaomicron
D. B. ureolyticus
B. ureolyticus
Which Clostridium species is most often recovered
from a wound infection with gas gangrene?
A. C. sporogenes
B. Clostridium sordellii
C. C. novyi
D. C. perfringens
C. perfringens
Routine laboratory testing for Treponema
pallidum involves:
A. Culturing
B. Serological analysis
C. Acid-fast staining
D. Gram staining
Serological analysis
Which of the following organisms is the cause of
Lyme disease?
A. Treponema pallidum
B. Neisseria meningitidis
C. Babesia microti
D. Borrelia burgdorferi
Borrelia burgdorferi
Spirochetes often detected in the hematology
laboratory, even before the physician suspects the
infection, are:
A. Borrelia spp.
B. Treponema spp.
C. Campylobacter spp.
D. Leptospira spp.
Borrelia spp.
Primary atypical pneumonia is caused by:
A. Streptococcus pneumoniae
B. Mycoplasma pneumoniae
C. Klebsiella pneumoniae
D. Mycobacterium tuberculosis
Mycoplasma pneumoniae
Which organism typically produces “fried-egg”
colonies on agar within 1–5 days of culture from a
genital specimen?
A. Mycoplasma hominis
B. Borrelia burgdorferi
C. Leptospira interrogans
D. Treponema pallidum
Mycoplasma hominis
Te manganous chloride–urea test is used for the
identification of which organism?
A. Mycoplasma pneumoniae
B. Ureaplasma urealyticum
C. Bacillus cereus
D. Borrelia burgdorferi
Ureaplasma urealyticum
Which is the test of choice for the confirmation of
Chlamydia trachomatis infection in urine?
A. Enzyme immunoassay antigen testing
B. PCR molecular testing
C. Culture using McCoy and Hela cells
D. Microimmunofluorescence (MIF) test
PCR molecular testing
Which test is the most reliable for the detection of
Mycoplasma pneumonia in serum and for the
confirmation of diagnosis?
A. EIA testing and direct antigen testing
B. Cold agglutinin testing using Group O RBCs
C. Culture on SP4 glucose broth with arginine
D. Complement fixation
EIA testing and direct antigen testing
Which of the following organisms are transmitted
to animals and humans after a tick bite?
A. Leptospira.
B. Chlamydia and Mycoplasma spp.
C. Neisseria sicca
D. Ehrlichia and Anaplasma spp
Ehrlichia and Anaplasma spp
Following a hike in the woods, a young male
noted a tick on his ankle. He removed the tick,
but 2 weeks later noticed a circular, bull’s eye rash
at the site of the bite. Which specimen(s) should
be obtained to establish a diagnosis of Lyme
borreliosis?
A. Lymph node biopsy, skin scraping
B. Blood, CSF, and skin biopsy
C. Hair, fingernails
D. Saliva, sputum
Blood, CSF, and skin biopsy
Methods other than packaged microsystems used
to identify anaerobes include:
A. Antimicrobial susceptibility testing
B. Gas–liquid chromatography (GLC)
C. Special staining
D. Enzyme immunoassay
Gas–liquid chromatography (GLC)
Which broth is used for the cultivation of
anaerobic bacteria in order to detect volatile fatty
acids as an aid to identification?
A. Prereduced peptone–yeast extract–glucose (PYG)
B. THIO broth
C. Gram-negative (GN) broth
D. Selenite (SEL) broth
Prereduced peptone–yeast extract–glucose (PYG)
Which test is performed in order to confirm an
infection with Clostridium botulinum?
A. Toxin neutralization
B. Spore-forming test
C. Lipase test
D. Gelatin hydrolysis test
Toxin neutralization
