©BRIGHTSTARS EXAM SOLUTIONS
11/16/2024 10:16 AM
PHMY 610 - Exam 4 (new material)
Questions With Correct Answers
Are enterobacterales falcultative or non-facultative anaerobes? - answer✔facultative
Enterobacterales are catalase what? - answer✔positive
Enterobacterales are oxidase what? - answer✔negative
what is a distinguishing factor of Enterobacterales? - answer✔they ferment glucose (some
lactose)
Enterobacterales all contain a heat-stable lipopolysaccharide that is composed of what 3
things? - answer✔1. O polysaccharide
2. common antigen
3. Lipid A
Lipid A is an endotoxin, but also considered what else for Enterobacterales? - answer✔a
virulence factor
Most Enterobacterales are motile with peritrichous flagella, except what 3 bugs? - answer✔1.
Klebsilla
2. Shigella
3. Yersinia
Where in the human body are Enterobacterales commonly found? - answer✔urinary tract,
vagina (females), and small intestine
what are some other virulence factors for Enterobacterales other than Lipid A (endotoxin)? -
answer✔hydrophilic capsule, antigenic phase variation, sequestration of growth factors,
resistance to serum killing, antimicrobial resistance
what is the most common medically important Enterobacterales? - answer✔Escherichia coli
1|Page
, ©BRIGHTSTARS EXAM SOLUTIONS
11/16/2024 10:16 AM
what type of media does MacConkey agar represent? - answer✔selective and differential
media
what are the selective ingredients for MacConkey agar? - answer✔bile salts and crystal violet
dye
what type of bacteria does MacConkey agar limit the growth of? - answer✔gram-positive
bacteria
what is the differential ingredients of MacConkey agar? - answer✔lactose
colorless colonies on a MacConkey agar represent what? - answer✔nonlactose fermenters
pink colonies on a MacConkey agar represent what? - answer✔lactose fermenters
what are 4 examples of non-lactose-fermenters? - answer✔1. Salmonella spp.
2. Shigella spp.
3. Proteus spp.
4. Serratia spp.
what are 4 examples of lactose-fermenters? - answer✔1. Escherichia coli
2. Klebsiella spp.
3. Enterobacter spp.
4. Citrobacter spp.
What is an exception to the Citrobacter spp. being lactose-fermenters? - answer✔C. koseri
what does the spot indole test determine? - answer✔the presence of the enzyme
tryptophanase, which converts tryptophan into indole
what results from a spot indole test indicate indole + and lactose fermenters? - answer✔blue or
blue-green color
what results from a spot indole test indicate indole - and lactose fermenters? - answer✔light
pink or colorless
what are some examples of Indole + and Lactose fermenters? - answer✔Escherichia coli and
Klebsiella oxytoca
2|Page
, ©BRIGHTSTARS EXAM SOLUTIONS
11/16/2024 10:16 AM
what are some examples of Indole - and Lactose fermenters? - answer✔Enterobacter cloacae,
Klebsiella aerogenes, Klebsiella pneumoniae, and Citrobacter freundii
what does the oxidase test determine? - answer✔production of cytochrome c oxidase
what is the oxidase reagent? - answer✔tetramethyl-p-phenylenediamine
Where does Escherichia coli typically colonize? - answer✔the GI tract
when does Escherichia coli typically cause infection? - answer✔when specialized virulence
factors are acquired
What other disease states is Escherichia coli associated with? - answer✔gastroenteritis, UTI's,
meningitis, and sepsis
what is the most common bug with Escherichia coli? - answer✔urinary tract infections
what type of agar does Escherichia coli undergo hemolysis? - answer✔blood agar
what are the 3 types of Escherichia coli that are associated with the small intestine? -
answer✔1. Enterotoxigenic Escherichia coli (ETEC)
2. Enteropathogenic Escherichia coli (EPAC)
3. Enteroaggregative Escherichia coli (EAEC)
what are the 2 types of Escherichia coli that are associated with the large intestine? -
answer✔1. Shiga Toxin-producing Escherichia (STEC)
2. Enteroinvasive Escherichia coli (EIEC)
how is most Escherichia coli transmitted? - answer✔fecal to oral exposure (contaminated
foods)
what is an exception to Escherichia coli transmission? - answer✔STEC is transmitted person to
person
What types of diarrhea are associated with enterotoxigenic Escherichia coli (ETEC)? -
answer✔traveler's diarrhea and infant diarrhea
what are some symptoms associated with enterotoxigenic Escherichia coli? - answer✔watery
diarrhea, n/v, cramps, and low-grade fever
what is the pathogenesis of enterotoxigenic Escherichia coli? - answer✔Heat stable (Sta and
Stb) and Heat labile (LT-I and LT-II) enterotoxins stimulate hypersecretion of fluids
3|Page
11/16/2024 10:16 AM
PHMY 610 - Exam 4 (new material)
Questions With Correct Answers
Are enterobacterales falcultative or non-facultative anaerobes? - answer✔facultative
Enterobacterales are catalase what? - answer✔positive
Enterobacterales are oxidase what? - answer✔negative
what is a distinguishing factor of Enterobacterales? - answer✔they ferment glucose (some
lactose)
Enterobacterales all contain a heat-stable lipopolysaccharide that is composed of what 3
things? - answer✔1. O polysaccharide
2. common antigen
3. Lipid A
Lipid A is an endotoxin, but also considered what else for Enterobacterales? - answer✔a
virulence factor
Most Enterobacterales are motile with peritrichous flagella, except what 3 bugs? - answer✔1.
Klebsilla
2. Shigella
3. Yersinia
Where in the human body are Enterobacterales commonly found? - answer✔urinary tract,
vagina (females), and small intestine
what are some other virulence factors for Enterobacterales other than Lipid A (endotoxin)? -
answer✔hydrophilic capsule, antigenic phase variation, sequestration of growth factors,
resistance to serum killing, antimicrobial resistance
what is the most common medically important Enterobacterales? - answer✔Escherichia coli
1|Page
, ©BRIGHTSTARS EXAM SOLUTIONS
11/16/2024 10:16 AM
what type of media does MacConkey agar represent? - answer✔selective and differential
media
what are the selective ingredients for MacConkey agar? - answer✔bile salts and crystal violet
dye
what type of bacteria does MacConkey agar limit the growth of? - answer✔gram-positive
bacteria
what is the differential ingredients of MacConkey agar? - answer✔lactose
colorless colonies on a MacConkey agar represent what? - answer✔nonlactose fermenters
pink colonies on a MacConkey agar represent what? - answer✔lactose fermenters
what are 4 examples of non-lactose-fermenters? - answer✔1. Salmonella spp.
2. Shigella spp.
3. Proteus spp.
4. Serratia spp.
what are 4 examples of lactose-fermenters? - answer✔1. Escherichia coli
2. Klebsiella spp.
3. Enterobacter spp.
4. Citrobacter spp.
What is an exception to the Citrobacter spp. being lactose-fermenters? - answer✔C. koseri
what does the spot indole test determine? - answer✔the presence of the enzyme
tryptophanase, which converts tryptophan into indole
what results from a spot indole test indicate indole + and lactose fermenters? - answer✔blue or
blue-green color
what results from a spot indole test indicate indole - and lactose fermenters? - answer✔light
pink or colorless
what are some examples of Indole + and Lactose fermenters? - answer✔Escherichia coli and
Klebsiella oxytoca
2|Page
, ©BRIGHTSTARS EXAM SOLUTIONS
11/16/2024 10:16 AM
what are some examples of Indole - and Lactose fermenters? - answer✔Enterobacter cloacae,
Klebsiella aerogenes, Klebsiella pneumoniae, and Citrobacter freundii
what does the oxidase test determine? - answer✔production of cytochrome c oxidase
what is the oxidase reagent? - answer✔tetramethyl-p-phenylenediamine
Where does Escherichia coli typically colonize? - answer✔the GI tract
when does Escherichia coli typically cause infection? - answer✔when specialized virulence
factors are acquired
What other disease states is Escherichia coli associated with? - answer✔gastroenteritis, UTI's,
meningitis, and sepsis
what is the most common bug with Escherichia coli? - answer✔urinary tract infections
what type of agar does Escherichia coli undergo hemolysis? - answer✔blood agar
what are the 3 types of Escherichia coli that are associated with the small intestine? -
answer✔1. Enterotoxigenic Escherichia coli (ETEC)
2. Enteropathogenic Escherichia coli (EPAC)
3. Enteroaggregative Escherichia coli (EAEC)
what are the 2 types of Escherichia coli that are associated with the large intestine? -
answer✔1. Shiga Toxin-producing Escherichia (STEC)
2. Enteroinvasive Escherichia coli (EIEC)
how is most Escherichia coli transmitted? - answer✔fecal to oral exposure (contaminated
foods)
what is an exception to Escherichia coli transmission? - answer✔STEC is transmitted person to
person
What types of diarrhea are associated with enterotoxigenic Escherichia coli (ETEC)? -
answer✔traveler's diarrhea and infant diarrhea
what are some symptoms associated with enterotoxigenic Escherichia coli? - answer✔watery
diarrhea, n/v, cramps, and low-grade fever
what is the pathogenesis of enterotoxigenic Escherichia coli? - answer✔Heat stable (Sta and
Stb) and Heat labile (LT-I and LT-II) enterotoxins stimulate hypersecretion of fluids
3|Page
