Enterobacteriaceae

Question 1

Describe the enterobacteriaceae family

Answer 1

Gram negative bacilli

Facultative anaerobes

Ferment glucose with acid production

Reduce nitrates to nitrites

Oxidase -ve

Grow on MacConkey agar

Non-sporing, non-acid fast

Question 2

Describe the antigenic structure of the enterobacteriaceae family

Answer 2

K/Capsular antigens:

Capsular polysaccharide
Heavy in Klebsiella

H/Flagella antigens:

Question 3

All enterobacteriaceae are motile except❓

Answer 3

Shigella

Klebsiella

Question 4

All enterobacteriaceae are non-capsulated except❓

Answer 4

Klebsiella

Question 5

List some examples of enterobacteriaceae

Answer 5

Escherichia

Shigella

Salmonella

Klebsiella

Enterobacter

Citrobacter

Serratia

Proteus

Morganella

Providencia

Erwinia

Yersinia

Edwardsiella

Hafnia

Question 6

What are examples of enterobacteriaceae that infect the CNS❓

Answer 6

E. coli

Question 7

What are examples of enterobacteriaceae that infect the lower respiratory system❓

Answer 7

E. coli

Klebsiella

Enterobacter

Question 8

What are examples of enterobacteriaceae that infect the blood stream❓

Answer 8

E. coli

Klebsiella

Enterobacter

Question 9

What are examples of enterobacteriaceae that infect the GIT❓

Answer 9

Salmonella

Shigella

Yersinia

E. coli

Question 10

What are examples of enterobacteriaceae that infect the urinary tract❓

Answer 10

E. coli

Proteus

Providentia

Klebsiella

Question 11

What are the site of infections for the enterobacteriaceae family❓

Answer 11

CNS

Lower respiratory system

Blood stream

GIT

Urinary tract

Question 12

E. coli…

1. Has which three antigens❓
2. Attach to epithelial surfaces using❓

Answer 12

1.
O-liposaccharide
K-capsule
H-flagellum

2. Pili

Question 13

What is the clinical significance of E.coli❓

Answer 13

UTI (esp in women)

Meningitis in infants (E. coli and grp B. strep)

Diarrhea in infants (EPEC)

Travelers diarrhea (ETEC)

Bloody diarrhea (EHER)

Dysentery-like Syndrome (EIEC)

Question 14

Diarrhea caused by EPEC is not bloody

True or false

Answer 14

True

Question 15

What does EAEC cause❓

Answer 15

Travellers Diarrhea

Persistent diarrhea in young children

Question 16

What dxs will…

1. EPEC
2. ETEC
3. EHEC
4. EIEC
5. EAEC

lead to❓

Answer 16

EPEC- Watery diarrhea in infants

ETEC- Watery diarrhea

EHEC- Bloody diarrhea, hemorrhagic colitis and HUS

EIEC- Bloody diarrhea

EAEC- persistent watery diarrhea

Question 17

How does salmonella typhi cause diseases❓

Answer 17

By invading macrophages of the intestinal lymphoid tissue (Peyer’s patches)

Spread to reticuloendothelial system and gallbladder

Question 18

“Rose spots” is associated with typhoid fever

True or false

Answer 18

True

Question 19

Salmonella thyphi is only transmitted via the oral-fecal route

True or false

Answer 19

True

Question 20

How can infections by shigella be transmitted❓

Answer 20

Contaminated food and water/contaminated stools

Question 21

What are the two clinically important shigella sps❓

Answer 21

Shigella sonnei

Shigella dysenteriae

Question 22

Shigella sonnei typically causes infections where❓

Answer 22

Mucosa of the large intestine

Rarely penetrates the deeper intestinal layers

Question 23

Shigella dysenteriae typically causes infections where❓

Answer 23

Invades the colonic mucosa

Produces exotoxins (Shiga toxin) w cytotoxic properties

Question 24

Shigellosis is characterised by

Answer 24

Diarrhea w blood, mucus and painful abdominal cramping

Question 25

Yersinia pestis... 1. Is transmitted by❓ 2. Spreads through which system❓ 3. Has an incubation period of❓ 4. Results in❓

Answer 25

1. Fleas/Contaminated animal tissues 2. Lymph nodes and phagocytes 2-8days 3. Bubonic/Septicemic plague

Question 26

Enterobacter frequently colonizes hospitalized pts True or false What dx can it lead to❓

Answer 26

True Associated w catheters and invasive procedures May infect burns, wounds, respiratory and urinary tracts

Question 27

What infections are associated with Klebsiella pneumonia and oxytoca ❓

Answer 27

Necrotizing lobar pneumonia UTI Bacteremia

Question 28

Which species of serratia causes human infections❓ What infections can it cause❓ Which other enterobacteriaceae cause extraintestinal infections❓

Answer 28

Serratia marcescens Extraintestinal infections of lower respiratory and urinary tract Proteus Providencia Morganella