RAPID LACTOSE FERMENTERS (COLIFORMS) – ESCHERICHIA

Colon’s Bacillus

Escherichia coli aka

T

Escherichia coli is pathogenic when it produces toxin (t/f)

Escherichia coli is the primary marker of fecal contamination in water purification

Escherichia coli is the primary marker of - contamination in -

O, H, K Ag

Escherichia coli ‘s Antigenic

1. ENDOTOXIN

2. COMMON PILI

3. K1 Ag (neonatal meningitis)

4. Intimin

Virulence Factors of Escherichia coli

UTI

Escherichia coli is the #1 cause of _______, Gram-negative sepsis

neonatal meningitis

Escherichia coli is the #2 cause of

1. Nosocomial

2. Wound

3. Bacteremia

4. Pneumonia

Other diseases of Escherichia coli is

diarrhea and gastroenteritis

Escherichia coli may cause

A/A + GAS

Laboratory Diagnosis of Escherichia coli

1. TSI: A/A + GAS

MViC: + + – –

Laboratory Diagnosis of Escherichia coli

2. IMViC: ___________

LOA: ++ –

Laboratory Diagnosis of Escherichia coli

3. LOA: ++-

Green Metallic Sheen

Laboratory Diagnosis of Escherichia coli

4. Eosin Methylene Blue: ___________________

E. coli O157:H7

Laboratory Diagnosis of Escherichia coli

5. MUG (+) except

Limulus Test

Laboratory Diagnosis of Escherichia coli

> detect bacterial endotoxin

Limulus horse crab

Laboratory Diagnosis of Escherichia coli

Limulus Test derived from

Enterotoxigenic Escherichia coli (ETEC)

Grows only on BAP

Traveler’s Diarrhea / Montezuma’s Revenge (Turista)

Enterotoxigenic Escherichia coli (ETEC) causes

1. Heat-Labile Toxin

2. Heat-Stable Toxin

Enterotoxigenic Escherichia coli (ETEC) 2 Toxins

Heat-Labile Toxin

Enterotoxigenic Escherichia coli (ETEC) 2 Toxins

similar to the “choleragen toxin” from V. cholerae

Heat-Labile Toxin

Enterotoxigenic Escherichia coli (ETEC) 2 Toxins

it also activates adenylate cyclase causing hypersecretion of both electrolytes and fluids into the intestinal lumen leading to WATERY DIARRHEA

Heat-Stable Toxin

Enterotoxigenic Escherichia coli (ETEC) 2 Toxins

stimulates guanylate cyclase which also leads to hypersecretion electrolytes and fluids into the intestinal lumen

Enteroinvasive Escherichia coli (EIEC )

Primary virulent factor of invasion

Dysentery-like Shigella

Enteroinvasive Escherichia coli (EIEC ) invades INTESTINAL EPITHELIUM causing

F

Enteroinvasive Escherichia coli (EIEC ) Shigella (the infective dose is as few as 10 bacterial cells) is more invasive than EIEC (the infective dose is 106), results to BLOODY STOOL with mucus and WBC (t/f)

Enteroinvasive Escherichia coli (EIEC ) EIEC (the infective dose is as few as 10 bacterial cells) is more invasive than Shigella (the infective dose is 106), results to BLOODY STOOL with mucus and WBC (t/f)

BLOODY STOOL with mucus and WBC

Enteroinvasive Escherichia coli (EIEC ) Shigella (the infective dose is as few as 10 bacterial cells) is more invasive than EIEC (the infective dose is 106), results to

Enteroinvasive Escherichia coli (EIEC)

Previously used to determine the virulence of both Shigella and EIEC

Enteroinvasive Escherichia coli (EIEC)

It determines the organism’s ability to produce KERATOCONJUNCTIVITIS in Guinea pig

SERENY TEST (+)

Enteroinvasive Escherichia coli (EIEC )

SERENY TEST

Enteropathogenic Escherichia coli (EPEC

nosocomial; outbreak of DIARRHEA among hospital nurseries

Enteropathogenic Escherichia coli (EPEC)

lacks the toxins of ETEC and invasiveness of EIEC and causes “INFANTILE DIARRHEA”

Enteropathogenic Escherichia coli (EPEC)

STOOL with LARGE AMOUNT OF MUCUS without blood

Enteropathogenic Escherichia coli (EPEC)

lacks the toxins of ETEC and invasiveness of EIEC and causes “INFANTILE DIARRHEA”

Enteroaggregative Escherichia coli (EAEC)

adheres to Hep2 cells, packed in a “STACKED BRICK” pattern

Enteroaggregative Escherichia coli (EAEC)

causes Acute or Chronic Diarrhea

Enteroaggregative Escherichia coli (EAEC)

causes diarrhea by adhering to the surface of intestinal mucosa

Diffusely adherent Escherichia coli (DAEC)

- associated with both UTI and gastrointestinal infections; “DIFFUSED PATTERN

Diffused Pattern

Diffusely adherent Escherichia coli (DAEC) is associated with both UTI and gastrointestinal infections; with what kind of PATTERN

Cystitis

Diffusely adherent Escherichia coli (DAEC) causes what dx in children

Acute pyelonephritis

Diffusely adherent Escherichia coli (DAEC) causes what dx in pregnant women

Enterohemorrhagic Escherichia coli (EHEC) / Vero-cytotoxic Escherichia coli (VTEC)

caused by the production of 2 cytotoxins: Verotoxin I and Verotoxin II

Enterohemorrhagic Escherichia coli (EHEC) / Vero-cytotoxic Escherichia coli (VTEC)

Associated with poorly cooked meat

Verotoxin 1

Enterohemorrhagic Escherichia coli (EHEC) / Vero-cytotoxic Escherichia coli (VTEC) may cause BLOODY DIARRHEA due to the production of

VEROTOXIN I

Enterohemorrhagic Escherichia coli (EHEC) / Vero-cytotoxic Escherichia coli (VTEC)

a cytotoxin resembling those of S. dysenteriae; produces damage to Vero cells (African-Green Monkey Kidney Cells)

VEROTOXIN II

Enterohemorrhagic Escherichia coli (EHEC) / Vero-cytotoxic Escherichia coli (VTEC)

biologically similar but immunologically different from Shiga toxin and Verotoxin I

HEMOLYTIC UREMIC SYNDROME (HUS)

O157:H7

Enterohemorrhagic Escherichia coli (EHEC) / Vero-cytotoxic Escherichia coli (VTEC) most severe manifestation is - associated with serotype E. coli -

E. coli O157:H7

a historical outbreak in fast-food chain (“JACK IN THE BOX”) serving undercooked burgers in 1993

Mug Test –

Enterohemorrhagic Escherichia coli (EHEC) / Vero-cytotoxic Escherichia coli (VTEC)

Mug Test

Mug Test –

Enterohemorrhagic Escherichia coli (EHEC) / Vero-cytotoxic Escherichia coli (VTEC)

do not produce glucuronidase

SMAC – colorless

Enterohemorrhagic Escherichia coli (EHEC) / Vero-cytotoxic Escherichia coli (VTEC)

SMAC

Enterohemorrhagic Escherichia coli (EHEC) / Vero-cytotoxic Escherichia coli (VTEC)

causes ENTERIC DISEASE HEMORRHAGIC COLITIS

Uropathogenic Escherichia coli (UPEC)

Most common cause of UTI in humans