Enterobacteriaceae and E.coli (Escherichia coli) Flashcards
Diagnosis of Enterobacteriaceae
Gram (-) bacilli, catalase (+), oxidase (-) facultative anaerobes, ferment glucose & other sugars (lactose)
Carbapenem resistant
Complications of Enterobacteriaceae
1) UTIs
2) intra-abdominal infections
3) Pneumonia
4) gastroenteritis
5) Bacteraemia
infection route of Enterobacteriacea
Colonizes the Oropharynx of hospitalised pateints
–> major cause of HA infections
(Antimicrobial resistant)
Diagnosis of E.coli
gram (-) bacilli
Diagnosis of Uropathogenic E.coli (UPEC)
1) Urine dipstick WBC (+), maybe RBC,
nitrates, leucocyte Estrace
2) Urinalysis –> WBC , maybe RBCs
3) Urine culture
Infection route of Uropathogenic E.coli
Colonises urethra –> ascends to the bladder (causes cystitis)
Pathogenesis/VF of Uropathogenic E.coli
UPEC produces –> P-fimbriae (type 1 fimbriae)
clinical manifestaions of Uropathogenic E.coli
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)
infection route of Enterotoxinogenic E. coli (ETEC)
Consumption of fecally contaminated food or water.
( no Person-to-person spread)
pathogenesis/ VF of Enterotoxinogenic E. coli (ETEC)
attach to small bowel epithelium & produce heat-stable toxins (STa & STb) and heat-labile toxins (LT-I, LT-II)
clinical manifestations of Enterotoxinogenic E.coli
1) Traveller’s Diarhhea (watery, non-bloody)
2) abdominal cramps,
3) nausea & vomiting
4) fever
5) Malaise
Infection route of Enteropathogenic E.coli
- person-person spread
characterised by “Attaching & Effacing” effect
No production of Shiga toxin
Pathogenesis of Enteropathogenic E.coli
*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
Clinical manifestaitons of Enteropathogenic E.coli
watery diarrhea, low-grade fever & vomiting
Diagnosis of Enteroaggregative E.coli (EAEC)
Aggregative pattern of appearance in tissue culture, 2D clusters on intestinal mucosa
pathogensis of Enteroaggregative E.coli
Mucosal damage, loss of microvilli & cell death –> Chronic diarrhea (>21d)
- Some produce toxins similar to ST by ETEC
*ETEC: Enterotoxoinogenic E.coli
Clinical manifestations of Enteroaggregative E.coli
Chronic diarrhea (>21d)
Diagnosis of Enteroinvasive E.coli
Ferment glucose and xylose
* this is how it is diffrentiated from Shigella
pathogenesis/ VF of Enteroinvasive E.coli
Have an invasion plasmid – invade colonic intestinal epithelial cells
clinical manifestations of Enteroinvasive E.coli
Watery diarrhea, may progress to dysentery with fever, abdominal cramps, small volume
bloody/mucoid stools
*Important
infection route of Enterohemorrhagic E.coli?
undercooked ground beef or contaminated vegetables, person-to-person,low infectious dose
VF of Enterohemorrhagic E.coli
Shiga toxins: block protein synthesis & induce cell death
clinical manifestaions of Enterohemorrhagic E.coli
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
complications of Hemolytic uremic syndrome (HUS):
1) Acute renal failure
2) Thrombocytopenia
3) Microangiopathic hemolytic anemia
Treatment of Hemolytic uremic syndrome (HUS)?
DO NOT TREAT WITH ANTIBIOTICS
(Antibiotics enhance production & release of Shiga-toxins & are associated with higher risk for HUS)
Complications of Escherichia coli (E.coli)
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
