Ch (7)

Question 1

Mention the 7 bacteria that consider as Opportunistic pathogens from the family of Enterobacteriaceae

Answer 1

Escherichia coli
Klebsiella pneumoniae
Enterobacter aerogenes
Serratia marcescens
Proteus spp.
Providencia spp.
Citrobacter spp.

Question 2

Mention the 4 bacteria that consider as Obligate pathogens from the family of Enterobacteriaceae

Answer 2

Salmonella spp.
Shigella spp.
Yersinia spp.
Some E. coli strains

Question 3

Which one of the following bacteria have smaller capsule (Klebsiella spp.) or (Enterobacter)

Answer 3

(Enterobacter)
Klebsiella spp. have large capsule
Enterobacter have smaller capsule;

Question 4

Which of the following bacteria is motile Klebsiella spp. or Proteus species

Answer 4

Proteus species
move very actively by means of
peritrichous flagella, resulting in
“swarming” on solid medium

Question 5

What is the result of Cytochrome oxidase for Enterobacteriaceae

Answer 5

negative

Question 6

What is the Breathing method of Enterobacteriaceae

Answer 6

Facultative anaerobes

Question 7

Which of the following statements is true about Enterobacteriaceae

Ability to oxide nitrates to nitrites

Ability to reduce nitrates to nitrites

Ability to reduce nitrites to nitrates

Ability to oxide nitrites to nitrates

Answer 7

Ability to reduce nitrates to nitrites

Question 8

Mention the 4 genera from the family of Enterobacteriaceae that can ferment lactose

Answer 8

Escherichia, Klebsiella, Citrobacter and Enterobacter. They are collectively called coliforms

Question 9

Mention the 4 genera from the family of Enterobacteriaceae that can’t ferment lactose

Answer 9

Salmonella, Shigella, Yersinia and Proteus

Question 10

Which of the following antigens consider as heat-stable and resistant to alcohol
O antigens (somatic)
H antigens (flagellar)
K antigens (capsular)

Answer 10

O antigens (somatic antigen)

Question 11

Which of the following antigens considers as Heat-labile and denatured by alcohol
O antigens
H antigens
K antigens

Answer 11

H antigens
The Flagellin antigen

Question 12

Give an example of selective differential media for Enterobacteriaceae

Answer 12

MacConkey agar

Question 13

Case study. A patient suffers from diarrhoea, and after tests it was discovered that the cause of the disease is E. coli or other opportunistic Enterobacteriaceae. What is the appropriate treatment that you recommend?

Answer 13

only symptomatic relief
because antibiotic treatment may prolong the fecal carriage or
increase the risk of secondary complications

Question 14

Case study. A patient suffers from bacteremia and septic shock, and after tests it was discovered that the cause of the disease is E. coli or other opportunistic Enterobacteriaceae. What is the appropriate treatment that you recommend?

Answer 14

prompt antibiotic treatment, restoration of fluid and electrolyte balance

Question 15

Mention the bacteria that consider as leading causes of meningitis in infants.

Answer 15

E . coli (particularly K1 strains) and S. agalactiae

Question 16

What’s the bacteria that considered as the most common cause of urinary tract infection.

Answer 16

E.coli

Question 17

Mention the strain of E.coli that is the major causal agent of Traveler’s diarrhea.

Answer 17

Enterotoxigenic E. coli (ETEC)

Question 18

Mention the strain of E.coli that causes infant diarrhea in poor countries.

Answer 18

Enteropathogenic E. coli (EPEC)

Question 19

Mention the strain of E.coli that causes dysentery-like
diarrhea and it’s closely related to Shigella

Answer 19

Enteroinvasive E. coli (EIEC)

Question 20

Mention the strain of E.coli that causes chronic diarrhea and growth retardation in infants in developing countries.

Answer 20

Enteroaggregative E. coli (EAEC)

Question 21

What is the most common strains from E.coli that produce diseases in developed countries.

Answer 21

Enterohemorrhagic E. coli (EHEC)

Question 22

Mention the strain of E.coli that is associated with hemorrhagic colitis and hemolytic uremic syndrome (HUS)

Answer 22

Enterohemorrhagic E. coli (EHEC)

Question 23

Which of the following is the serotype that is the most common isolated from Enterohemorrhagic E. coli (EHEC)
O157:H7
O152:H6
O157:H6
O152:H7

Answer 23

O157:H7

Question 24

Verotoxin or Shiga toxin produced by which of the following bacteria
Enterotoxigenic E. coli
Enteropathogenic E. coli
Enterohemorrhagic E. coli
Enteroinvasive E. coli
Enteroaggregative E. coli

Answer 24

Enterohaemorrhagic E. coli

Question 25

What is the colour of colonies of E.coli when cultures on MacConkey’s medium.

Answer 25

rose-pink colonies

Yellow colonies on XLD and CLED agar

Question 26

Which of the following statements is true about E.coli

Ferment glucose, lactose, maltose, mannite, sucrose and salicin with production of alcohol

Ferment glucose, lactose, maltose, mannite, sucrose and salicin with production of acid and gas

Ferment glucose, lactose, maltose, mannite, sucrose and salicin with production of acid and no gas

Ferment glucose, lactose, maltose, mannite, sucrose and salicin with production of gas and no acid

Answer 26

Ferment glucose, lactose, maltose, mannite, sucrose and salicin with production of acid and gas.

Question 27

Right the biochemical activity of E.coli for each of the following
Indol
MR
Motility
VP
Citrate

Answer 27

Indol +
MR +
Motility +
VP -
Citrate -

Question 28

Mention the genus of Enterobacteriaceae that cause traveller’s diarrhea

Answer 28

Providencia

Question 29

What is the most common species of proteus that cause UTI

Answer 29

Proteus mirabilis

Question 30

What is the only specie from proteus that gives Indole negative

Answer 30

Proteus mirabilis