Introduction to Diagnostic Microbiology for the
Laboratory Sciences 3rd Edition 2025 Latest
Update Graded A+
QUESTIONS
A pharyngeal specimen is inoculated on cystine-tellurite blood agar, modified
Tinsdale agar, and MacConkey agar. After 48 hours of incubation, black colonies
with a brown halo are observed on the Tinsdale agar and gray colonies are
isolated from the cystine-tellurite agar. However, no growth is observed on the
MacConkey agar. Which of the following statements explains this discrepancy?
no discrepancy is present; this organism does not grow on mac agar
A catalase-positive, non-spore-forming, gram-positive rod that is not acid-fast
could possibly belong to which group of bacteria?
corynebacterium
A catalase-negative, non-spore-forming, nonbranching, gram-positive rod that
produces hydrogen sulfide when inoculated into tripe sugar iron (TSI) agar is
most likely:
erysipelothrix
A CAMP test is positive for these small gram-positive bacilli. Which beta-
hemolytic organism is used in conjunction with this organism in the CAMP test?
s. aureus
,Clue cells are associated with which gram-positive bacilli?
gardnerella vaginalis
Which describes aerotolerant Actinomyces?
rudimentary branching "antlers" morphology on gram stain
generally not acid fast
normal flora of the oral cavity
Nocardia is an aerobic, partially acid-fast gram positive bacillus.
true
Which of the following bacteria has been linked to food poisoning in fried rice?
bacillus cereus
Which test is used to differentiate the Viridans streptococci from the Group D
streptococcis and Enterococci?
bile esculin test
A gram-positive bacillus identified as Lactobacillus is isolated in large quantities
from the urine of a 16-year-old female. Based on this information, the patient
should receive which antibiotic?
no antibiotics should be administered
What media does Corynebacterium diphtheriae grow on?
sheep blood agar
loeffler
potassium tellurite
,Bacteria described as being coryneform have which of the following
morphologic features?
resemble and are often referred to as chinese letters
Which statement correctly describes Lactobacillus?
produces large quantities of lactic acid
To differentiate Bacillus anthracis and Bacillus cereus:
B cereus is beta hemolytic and motile; B. anthracis is non-hemollytic and
nonmotile.
An organism associated with bacterial vaginosis is:
gardnerella
What are the oxygen requirements for Staphylococcus and Micrococcus?
staph is a facultative anaerobe; micrococcus is an obligate aerobe
A cerebrospinal fluid (CSF) culture was performed on a newborn in distress.
After overnight incubation, small gram-positive cocci with a soft zone of beta
hemolysis grew on sheep blood agar. Based on this information, what results
would be expected on the following tests: catalase; Christie, Atkins, Munch-
Petersen (CAMP); and motility?
negative catalase, positive CAMP, and negative motility
The wet mount and Gram stain of vaginal secretions from a patient who has
bacterial vaginosis caused by Gardnerella vaginalis will reveal large:
, squamous epithelial cells with numerous attached pleomorphic gram-variable or
gram-negative coccobacilli and rods.
Which of the following is NOT true about Bacillus anthracis?
it is motile
In clinical isolates, the most likely identification of coagulase-negative, catalase-
positive, gram-positive cocci would be:
staphylococcus lugdunensis
You have isolated small, white, beta-hemolytic colonies on blood agar. Gram
stain shows gram positive cocci. You then perform a catalase test on the isolate.
What reagent do you need to perform a catalase test?
hydrogen peroxide
An organism grows on a mannitol salt plate with yellow colonies after 24 hours
of incubation. Interpret these results.
organism utilized the mannitol in the agar as a nutritional source
organism could grow in salt-enriched agar
Which organism causes this positive CAMP reaction?
streptococcus agalactiae
The PBP2a test confirms:
MRSA
Which of the following is (are) true about Listeria monocytogenes?
Laboratory Sciences 3rd Edition 2025 Latest
Update Graded A+
QUESTIONS
A pharyngeal specimen is inoculated on cystine-tellurite blood agar, modified
Tinsdale agar, and MacConkey agar. After 48 hours of incubation, black colonies
with a brown halo are observed on the Tinsdale agar and gray colonies are
isolated from the cystine-tellurite agar. However, no growth is observed on the
MacConkey agar. Which of the following statements explains this discrepancy?
no discrepancy is present; this organism does not grow on mac agar
A catalase-positive, non-spore-forming, gram-positive rod that is not acid-fast
could possibly belong to which group of bacteria?
corynebacterium
A catalase-negative, non-spore-forming, nonbranching, gram-positive rod that
produces hydrogen sulfide when inoculated into tripe sugar iron (TSI) agar is
most likely:
erysipelothrix
A CAMP test is positive for these small gram-positive bacilli. Which beta-
hemolytic organism is used in conjunction with this organism in the CAMP test?
s. aureus
,Clue cells are associated with which gram-positive bacilli?
gardnerella vaginalis
Which describes aerotolerant Actinomyces?
rudimentary branching "antlers" morphology on gram stain
generally not acid fast
normal flora of the oral cavity
Nocardia is an aerobic, partially acid-fast gram positive bacillus.
true
Which of the following bacteria has been linked to food poisoning in fried rice?
bacillus cereus
Which test is used to differentiate the Viridans streptococci from the Group D
streptococcis and Enterococci?
bile esculin test
A gram-positive bacillus identified as Lactobacillus is isolated in large quantities
from the urine of a 16-year-old female. Based on this information, the patient
should receive which antibiotic?
no antibiotics should be administered
What media does Corynebacterium diphtheriae grow on?
sheep blood agar
loeffler
potassium tellurite
,Bacteria described as being coryneform have which of the following
morphologic features?
resemble and are often referred to as chinese letters
Which statement correctly describes Lactobacillus?
produces large quantities of lactic acid
To differentiate Bacillus anthracis and Bacillus cereus:
B cereus is beta hemolytic and motile; B. anthracis is non-hemollytic and
nonmotile.
An organism associated with bacterial vaginosis is:
gardnerella
What are the oxygen requirements for Staphylococcus and Micrococcus?
staph is a facultative anaerobe; micrococcus is an obligate aerobe
A cerebrospinal fluid (CSF) culture was performed on a newborn in distress.
After overnight incubation, small gram-positive cocci with a soft zone of beta
hemolysis grew on sheep blood agar. Based on this information, what results
would be expected on the following tests: catalase; Christie, Atkins, Munch-
Petersen (CAMP); and motility?
negative catalase, positive CAMP, and negative motility
The wet mount and Gram stain of vaginal secretions from a patient who has
bacterial vaginosis caused by Gardnerella vaginalis will reveal large:
, squamous epithelial cells with numerous attached pleomorphic gram-variable or
gram-negative coccobacilli and rods.
Which of the following is NOT true about Bacillus anthracis?
it is motile
In clinical isolates, the most likely identification of coagulase-negative, catalase-
positive, gram-positive cocci would be:
staphylococcus lugdunensis
You have isolated small, white, beta-hemolytic colonies on blood agar. Gram
stain shows gram positive cocci. You then perform a catalase test on the isolate.
What reagent do you need to perform a catalase test?
hydrogen peroxide
An organism grows on a mannitol salt plate with yellow colonies after 24 hours
of incubation. Interpret these results.
organism utilized the mannitol in the agar as a nutritional source
organism could grow in salt-enriched agar
Which organism causes this positive CAMP reaction?
streptococcus agalactiae
The PBP2a test confirms:
MRSA
Which of the following is (are) true about Listeria monocytogenes?
