Enterobacteriaceae Flashcards
Which of the following is NOT a characteristic of Yersinia pestis?
a. It produces VW antigen
b. It is a spore former
c. It is a facultative intracellular bacillus.
d. It is transmitted thru the bite of infected fleas
B
Explanation: In general,
enterobacteria are not
spore-formers
Which of the following gram-negative rods is LEAST likely to cause UTI in a hospitalized patient?
a. Proteus mirabilis
b. Enterobacter aerogenes
c. Salmonella typhimurium
d. Klebsiella pneumoniae
C
Explanation: S. typhirimium causes gastroenteritis
Which among the gram-negative rods producing gastroenteritis
is the most infectious to man?
a. Enterotoxigenic E. coli (ETEC)
b. Shigella dysenteriae
c. Campylobacter jejuni
d. Salmonella typhimurium
B
Which of the following genera of enterics produces urease enzymes thereby causing Urinary Tract Infection?
a. Morganella
b. Escherichia
c. Proteus
d. Klebsiella
C
Which of the following host defense mechanism is the MOST important for preventing dysentery caused by Shigella?
a. Bile in the small intestines
b. Normal flora of the mouth
c. Salivary enzymes
d. Gastric acid
D
Which of the following is the mode of transmission of Yersinia pestis to man?
a. IIngestion of contaminated water
b. Bite of infected flea
c. Skin to skin contact
d. Airborne transmission
B
When symptoms of typhoid fever first become apparent, from which of the following specimens is the causative organism frequently isolated?
a. Bone marrow
b. Urine
c. Feces
d. Blood
D
Which of the following tests can differentiate Yersinia spp. from Pasteurella spp.?
a. Oxidase test
b. Gram staining
c. Test for motility
d. Catalase
A
A answer B-D similar Yersinia - (-) oxidase, gram neg, motile at 30C, (+) catalase Pasteurella - (+) oxidase, gram neg, motile, (+) catalase
A 30 y/o female sex worker who has recurrent urinary tract infections, describes her urine as ammonia-like smell. Which of the following is likely the cause of her condition?
a. Citrobacter freundii
b. Serratia marcescens
c. Enterobacter aerogenes
d. Proteus mirabilis
D
The urine smells strongly of
ammonia due to the conversion of
urea in the urine by the urease enzyme.
Which gram negative rod is the most likely cause of pneumonia in COPD, alcoholics, elderly, & presents with bloody mucoid
sputum?
a. Haemophilus influenzae
b. Klebsiella pneumoniae
c. Pasteurella multocida
d. Pseudomonas aeruginosa
B
Bloody mucoid sputum = Currant jelly All gram neg rods and causes pneumonia A bloody mucoid "Currant jelly" B green sputum C green sputum
A 5 y/o child has mucoid and bloody diarrhea. Culture on MAC medium showed small tiny colorless colonies. Which of the following virulence factors is most likely responsible for the presence of mucus & blood?
a. SHET 1 toxin
b. Presence of capsule
c. Enterotoxin
d. Fimbriae
A
Diagnosis: Shigella A Virulence factor - SHET1 B not produced by shigella C fimbriae not required for cell invasion D no capsule
Which of the following organisms can cause gastroenteritis
from a Caesar’s salad prepared with raw eggs?
a. Salmonella typhimurium
b. Enterotoxigenic E. coli
c. Shigella dysenteriae
d. Vibrio cholerae
A
B, C, & D mostly taken in thru
contaminated water
A - both through contaminated water and raw eggs
A 25 y/o male consults at the ER due to fever of 6 days, associated with abdominal pain. He is suspected to have Enteric
fever. Which of the following tests will be most helpful in the diagnosis?
a. Stool culture
b. Blood culture
c. Urine culture
B
Blood - 1st week in the bloodstream
Stool - 2nd week go back to
intestine
Urine - 3rd week go to kidney
Which of the following E.coli serogroups is similar to Vibrio
cholerae in producing Labile and stable toxin?
a. Enterotoxigenic E. coli (ETEC)
b. Enteroinvasive E. coli (EIEC)
c. Enterohemorrhagic E. coli (EHEC)
d. Enteropathogenic E. coli (EPEC)
A
E.coli & V. cholerae - produce enterotoxin
EHEC - release shiga-like toxin; results in local and systemic effects
EIEC - invades the colonic mucosa, giving rise to an inflammatory enteritis
EPEC - elicits the attaching and effacing lesion in the small bowel, resulting in intestinal secretion.
What organism is a gram negative, facultative intracellularbacillus marked by bipolar thickening & produces V & W Antigen to facilitate intracellular spread?
a. Yersinia pestis
b. Haemophilus influenzae
c. Pseudomonas aeruginosa
d. Pasteurella multocida
A
V & W antigen can only be found in
Yersinia pestis
Which of the following gastrointestinal diseases will NOT show evidence of morphologic alteration of intestinal epithelium?
a. Shigellosis
b. Hemorrhagic colitis
c. Campylobacter gastroenteritis
d. Cholera
D
A-C invasive, produce mucus & blood in the stool D answer
Which of the following mechanisms is the action of Heat-labile toxin of Enterotoxigenic E. coli?
a. Attachment & effacement
b. Activation of adenylyl cyclase
c. Aggregative adherence
d. Flattening of the microvilli
B
Enterotoxin A. not attachment (EPEC or EIEC) B. ETEC (answer) C. EAEC D. elongation (DAEC)
Which of the following diarrheic strains of E. coli is the common cause of traveler’s diarrhea?
a. Enterotoxigenic E. coli (ETEC)
b. Enterohemorrhagic E.coli (EHEC)
c. Enteroinvasive E. coli (EIEC)
d. Enteropathogenic E. coli (EPEC)
A
ETEC - Traveler’s diarrhea EHEC - Hemorrhagic colitis / Hemolytic uermic syndrome (HUS) EIEC - Dysentery EPEC - Diarrhea (neonate/young children)
Which of these organisms is NOT associated with infection producing bloody mucoid stool?
a. Enterotoxigenic E. coli
b. Shigella dysenteriae
c. Entamoeba histolytica
d. Enteroinvasive E. coli
A
Looking for Noninvasive
B-D invasive
A answer
tip: ETEC = Traveler’s diarrhea = watery
Chronic carriers are typically associated with the dissemination of which of the following bacteria?
a. Bordetella pertussis
b. Helicobacter pylori
c. Salmonella typhi
d. Vibrio cholerae
C
Bordetella, helicobacter, Vibrio - technically not carriers and excrete the organisms (acute)
Salmonella - chronic for more than a year • Can be asymptomatic • Bacteria lodges in the gallbladder ◦ Risk factor for CA • Long term sequela • Typhoid Mary • Salmonella persists in biofilms on gallstones and the gallbladder epithelium • Carriers secrete the bacilli in the urine & stool
Motivation Card!
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