Enterobacteriaceae and E.coli (Escherichia coli)

Question 1

Diagnosis of Enterobacteriaceae

Answer 1

Gram (-) bacilli, catalase (+), oxidase (-) facultative anaerobes, ferment glucose & other sugars (lactose)
Carbapenem resistant

Question 2

Complications of Enterobacteriaceae

Answer 2

1) UTIs
2) intra-abdominal infections
3) Pneumonia
4) gastroenteritis
5) Bacteraemia

Question 3

infection route of Enterobacteriacea

Answer 3

Colonizes the Oropharynx of hospitalised pateints
–> major cause of HA infections
(Antimicrobial resistant)

Question 4

Diagnosis of E.coli

Answer 4

gram (-) bacilli

Question 5

Diagnosis of Uropathogenic E.coli (UPEC)

Answer 5

1) Urine dipstick WBC (+), maybe RBC,
nitrates, leucocyte Estrace
2) Urinalysis –> WBC , maybe RBCs
3) Urine culture

Question 6

Infection route of Uropathogenic E.coli

Answer 6

Colonises urethra –> ascends to the bladder (causes cystitis)

Question 7

Pathogenesis/VF of Uropathogenic E.coli

Answer 7

UPEC produces –> P-fimbriae (type 1 fimbriae)

Question 8

clinical manifestaions of Uropathogenic E.coli

Answer 8

1) Cystitis
–> Dysuria & urinary urgency. Smelly urine, might be bloody. Cystitis DOES NOT cause high fever

2) Pyelonephritis
–> High fever, chills, vomitting, costoverterbal angle pain (GIORGANO SIGN )
–> causes SERIOUS INFECTION (that may lead to bactermeia and sepsis)

Question 9

infection route of Enterotoxinogenic E. coli (ETEC)

Answer 9

Consumption of fecally contaminated food or water.
( no Person-to-person spread)

Question 10

pathogenesis/ VF of Enterotoxinogenic E. coli (ETEC)

Answer 10

attach to small bowel epithelium & produce heat-stable toxins (STa & STb) and heat-labile toxins (LT-I, LT-II)

Question 11

clinical manifestations of Enterotoxinogenic E.coli

Answer 11

1) Traveller’s Diarhhea (watery, non-bloody)
2) abdominal cramps,
3) nausea & vomiting
4) fever
5) Malaise

Question 12

Infection route of Enteropathogenic E.coli

Answer 12

• person-person spread

characterised by “Attaching & Effacing” effect
No production of Shiga toxin

Question 13

Pathogenesis of Enteropathogenic E.coli

Answer 13

*NO production of Shiga toxins
Charctersised by “attaching & effacing” effect
(attach to apical surface of small intestine epithelial cells & loss of microvilli – form cup-like pedestal)
- Loss of microvilli--> malabsorption –> Profuse diarrhea

Question 14

Clinical manifestaitons of Enteropathogenic E.coli

Answer 14

watery diarrhea, low-grade fever & vomiting

Question 15

Diagnosis of Enteroaggregative E.coli (EAEC)

Answer 15

Aggregative pattern of appearance in tissue culture, 2D clusters on intestinal mucosa

Question 16

pathogensis of Enteroaggregative E.coli

Answer 16

Mucosal damage, loss of microvilli & cell death –> Chronic diarrhea (>21d)

• Some produce toxins similar to ST by ETEC

*ETEC: Enterotoxoinogenic E.coli

Question 17

Clinical manifestations of Enteroaggregative E.coli

Answer 17

Chronic diarrhea (>21d)

Question 18

Diagnosis of Enteroinvasive E.coli

Answer 18

Ferment glucose and xylose
* this is how it is diffrentiated from Shigella

Question 19

pathogenesis/ VF of Enteroinvasive E.coli

Answer 19

Have an invasion plasmid – invade colonic intestinal epithelial cells

Question 20

clinical manifestations of Enteroinvasive E.coli

Answer 20

Watery diarrhea, may progress to dysentery with fever, abdominal cramps, small volume
bloody/mucoid stools

Question 21

*Important
infection route of Enterohemorrhagic E.coli?

Answer 21

undercooked ground beef or contaminated vegetables, person-to-person,low infectious dose

Question 22

VF of Enterohemorrhagic E.coli

Answer 22

Shiga toxins: block protein synthesis & induce cell death

Question 23

clinical manifestaions of Enterohemorrhagic E.coli

Answer 23

1) Severe abdominal cramping,
2) watery or bloody diarrhea.
3) Absence of fever
4)** HUS & leading cause of renal insufficieny in children**

*HUS: Uremic Heamolytic sundrome

Question 24

complications of Hemolytic uremic syndrome (HUS):

Answer 24

1) Acute renal failure
2) Thrombocytopenia
3) Microangiopathic hemolytic anemia

Question 25

Treatment of Hemolytic uremic syndrome (HUS)?

Answer 25

DO NOT TREAT WITH ANTIBIOTICS
(Antibiotics enhance production & release of Shiga-toxins & are associated with higher risk for HUS)

Question 26

Complications of Escherichia coli (E.coli)

Answer 26

1) Number 1 cause of** CA-UTIs (&HA-UTIs**)
2) Number 1 cause of Traveller’s Diarrhea
3) Second casue of Neonatal Meningitis (After S.agalactiae)
4) Gasteronteritis
5) Sepsis