Enterobacteriaceae

Question 1

All Enterobacteriaceae are:

Answer 1

gram-negative rods, oxidase negative

Question 2

A urine culture isolate interim report:
>100,000 colony forming units/ml lactose-fermenting gram-negative rod

This indicates the organism most likely is:

Answer 2

Escherichia coli, Klebsiella sp., Enterobacter sp. or Citrobacter freundii

Question 3

Endotoxic shock can cause leukocytosis, thrombocytopenia, disseminated intravascular coagulation, fever and hypotension.
This is caused by:

Answer 3

exposed components of lipopolysaccharide in Enterobacteriaceae cell walls when bacterial cells are lysed

Question 4

An Enterobacteriaceae organism known to cause pneumonia is:

Answer 4

Klebsiella sp.- Can cause a reddish color sputum specimen

Question 5

An organism that is known to cause gastroenteritis in children, mimic appendicitis and contaminate blood products used for transfusion is most consistent with:

Answer 5

Yersinia entercolitica

Question 6

Antimicrobial treatment is usually not recommended with gastroenteritis caused by:

Answer 6

Shiga-toxin producing E. coli and Salmonella sp.: Antimicrobial treatment is not recommended for Shiga-toxin producing E. coli as such treatment may increase the risk of HUS development due to the release of toxin. Treating Salmonella sp. infections can prolong the disease. Antimicrobial treatment is usually recommended only in patients 50 years of age.

Question 7

An organism causing watery diarrhea, abdominal pain and vomiting that can lead to hemolytic uremic syndrome (HUS) is most consistent with:

Answer 7

Escherichia coli Shiga toxin producing strains: HUS is caused by Shiga-toxin producing strains of Escherichia coli. The most common strain is Escherichia coli O157:H7.

Question 8

What is the #1 etiologic agent of UTIs?

Answer 8

E.coli- can also cause meningitis in 0-3 month age group, most common aerobic GNR in intestine

Question 9

What organism is documented cause of nursery outbreaks of neonatal meningitis and brain abscesses?

Answer 9

Citobacter sp. Also causes opportunistic ITI, bacteremia, wound. Intrinsically resistant to ampicillin/amoxacillin, 1st generation cephalosporins

Question 10

E. coli is associate with what type of infection? Klebsiella? Proteus?

Answer 10

E.coli= UTI
Klebsiella= pneumonia
Proteus= Renal calculi

Question 11

T/F: Enterobacteriaceae are glucose fermenters?

Answer 11

True

Question 12

True/False: Enterobacteriaceae are oxidase positive?

Answer 12

False: Oxidase negative

Question 13

T/F: Enterobacteriaceae will grow on MacConkey Agar and are all lactose fermenters

Answer 13

False: They will grow on MacConkey agar but may be lactose or non-lactose fermenters

Question 14

99% of lactose fermenting GNR will be a member of enterobacteriaceae and will be what organisms?

Answer 14

1) E. coli
2) Klebsiella pneumo or K. oxytoca
3) Enterobacter aerogenes or E. cloacae
4) Citrobacter freundii

Question 15

Which of the following is not a lactose-fermenting GNR?
A) E. coli
B) Citrobacter freundii
C) Enterobacter sp.
D) Proteus sp.

Answer 15

D) Proteus sp.

Question 16

A lactose fermenting gram-negative rod that causes a destructive pneumonia is most consistent with…

Answer 16

Klebsiella sp.

Question 17

An E.coli is reported as an extended -spectrum beta lactamase producer. This indicates the organism is resistant to:

Answer 17

Penicillins, most cephalosporins and aztreonam

Question 18

How is shigella sp. transferred?

Answer 18

Person to person

Question 19

What organism would you suspect in a patient with travel history and main symptom is a fever?

Answer 19

Salmonella typhi

Question 20

What 5 organisms that we talked about cause bacterial gastroenteritis?

Answer 20

E. Coli, Shigela, Salmonella, Yersinia, campylobacter

Question 21

Specimen of choice to culture to diagnose Salmonella Typhi infection during the first 3 weeks of symptoms is:

Answer 21

Blood

Question 22

Which of the following organisms is considered a pathogen when isolated from stool?
A) Campylobacter sp.
B) Citrobacter sp.
C) Klebsiella sp.
D) Proteus sp.

Answer 22

A) Campylobacter sp.

Question 23

What organism is associated with bubonic plague?

Answer 23

Yersinia pestis- Order blood and sputum

Question 24

T/F: Yersinia entercolitica and Shiga-toxin producing E.coli usually have to request specific culture?

Answer 24

True