6.2 enterobacteriaceae E. coli

Question 1

E. coli has some strains that are …. whilst others are ….

Answer 1

• opportunistic pathogens
• pathogenic

Question 2

Name 2 common virulence factors of E.coli

Answer 2

• adhesins
• exotoxins

Question 3

E. coli virulence factors

Answer 3

Gram negative
Fimbriae — cystitis and pyelonephritis
K capsule — pneumonia, neonatal meningitis
LPS endotoxin — septic shock

Question 4

E. coli infection leads to what conditions?

Answer 4

Gastroenteritis
UTIs
Meningitis
Sepsis

Question 5

Transmission of E. coli

Answer 5

Fecal-oral route
Ingestion of contaminated food/water
Consumption of undercooked or beef/unpasteurised milk

Question 6

What strain causes E.coli O157:H7 gastroenteritis ?

Answer 6

STEC or EHEC strains of E.coli

shiga toxin - producing or enterohaemorrhagic

Question 7

ETEC (Enterotoxigenic) strain leads to which diseases?

Answer 7

• Traveller’s diarrhoea
• Infant diarrhoea
• Watery non-bloody diarrhoea, vomiting, cramps, nausea, low-grade fever

Question 8

What are the virulence factors associated with ETEC?

Answer 8

• Heat labile (HT) and heat stable (Sta) enterotoxins
• Colonisation factor antigens

Question 9

EPEC (Enteropathogenic) strain leads to which diseases?

Answer 9

• Infant diarrhoea
• Watery diarrhoea, vomiting

Question 10

What are the virulence factors associated with EPEC?

Answer 10

• Bundle-forming pili
• Intimin

Question 11

EAEC (Enteroaggregative) strain leads to which diseases?

Answer 11

• Infant diarrhoea
• People with HIV
• Traveller’s diarrhoea
• Watery diarrhoea, vomiting, dehydration, low-grade fever

Question 12

What are the virulence factors associated with EAEC?

Answer 12

• Aggregative adherence fimbriae
• Enteroaggregative heat stable toxin
• Plasmin-encoded toxin

Question 13

STEC (Shiga-toxin producing) or EHEC (Enterohaemorrhagic) strain leads to which diseases?

Answer 13

• Diarrhoea
• Watery diarrhoea followed by bloody diarrhoea (hemorrhagic colitis) with abdominal cramps, no or low-grade fever and haemolytic uremic syndrome (HUS)

Question 14

What are the virulence factors associated with STEC/EHEC

Answer 14

• Bundle-forming pili
• Intimin
• Shiga toxins (Stx1, Stx2)

Question 15

EIEC (Enteroinvasive) strain leads to which disease?

Answer 15

• Fever, cramping, watery diarrhoea, may progress to dysentery with scant bloody stools

Question 16

What are the virulence factors associated with EIEC?

Answer 16

• Haemolysin

Question 17

What is E.coli O157:H7 the most common cause of ?

Answer 17

Haemorrhagic colitis and haemolytic uermic syndrome

Question 18

E. coli O157: H7 Gastroenteritis
What strain causes this disease?

Answer 18

STEC (Shiga toxin-producing) or EHEC (Enterohaemorrhagic) strains of E. coli

Question 19

E. coli O157: H7 Gastroenteritis
What are the common sources of infection?

Answer 19

• Undercooked beef
• Unpasteurised milk

Question 20

E. coli O157: H7 Gastroenteritis
Incubation period

Answer 20

1-8 days

Question 21

E. coli O157: H7 Gastroenteritis
Treatment ?

Answer 21

1. rehydration therapy
2. antibiotics
3. blood transfusion & haemolysis

Question 22

E. coli O157: H7 Gastroenteritis
Treatment: Rehydration therapy includes ?

Answer 22

• electrolytes
• fluids

Question 23

E. coli O157: H7 Gastroenteritis
Treatment: antibiotics includes ?

Answer 23

• Ciprofloxacin
  Trimethoprim/Sulfamethoxazole
• Ampicillin, Cefotaxime

Question 24

E. coli O157: H7 Gastroenteritis
Treatment: blood transfusion and haemolysis includes ?

Answer 24

• blood transfusions offered in the case of patient developing life-threatenign hemolytic uermic syndrome (10-15% cases)