Enterobacteriaceae (E.coli, Salmonella, Yersenia)🚽🤮 Flashcards
Overt pathogens of the gastrointestinal tract
Lactose fermenters?
macConKEES
Citrobacter
Klebsiella
Escherichia
Enterobacter
Serratia
Enterobacteriaceae oxidase negative (except for ______ spp.)
Plesiomonas
All are catalase positive except
Shigella dysenteriae type 1
Antigenic classification
this is a heat-stable antigen located on the cell wall.
O antigen
Antigenic classification
this is a heat-labile antigen found on the surface of flagella, structures responsible for motility.
H antigen
Antigenic classification
this is a heat-labile polysaccharide found only in certain encapsulated species.
K antigen
K1 antigen is found on?
E. coli
Vi antigen is found on?
Salmonella enterica subsp. enterica serotype Typhi.
Primary marker of fecal contamination in water quality testing.
Escherichia coli
Antigenic classification of E.coli
O, H, and K antigens.
- Ferments of glucose, lactose, trehalose, and xylose
E.coli
Lipid A portion of lipopolysaccharide (LPS). (toxin)
Endotoxin
strain of E. coli most common cause of UTIs in humans
UPEC
E. coli strain with PILI, CYTOLYSIN, AEROBACTIN
UPEC
allow bacterial cells to chelate iron
AEROBACTIN
kill immune cells and inhibit phagocytosis and
chemotaxis
CYTOLYSIN
5 major categories of E.coli
ETEC
EPEC
EIEC
EHEC
Enteroadherent - (DAEC & EAEC)
What type of Enteroadherent E.coli
- Associated with both UTI and GIT infections
- Causes cystitis in children and acute pyelonephritis in pregnant women
DAEC (Diffusely Adherent E. coli)
- Causes diarrhea by adhering to the surface of intestinal mucosa
- Adheres to HEp2 cells, packed in a “stacked-brick” pattern
EAEC (Enteroaggregative E. coli)
Traveler’s diarrhea a.k.a Montezuma’s revenge or La Tourista
ETEC: ENTEROTOXIGENIC E. coli
Infective dose of ETEC
10^6 to 10^10
Produces heat stable toxin similar to choleragen toxin from Vibrio cholera
ETEC
ETEC strain
Activates adenylate cyclase:
hypersecretion of both electrolytes and fluids into the intestinal lumen leading to water diarrhea
Heat-labile Toxin (LT)
Stimulates guanylate cyclase:
which leads to hypersecretion of electrolytes and water into the intestinal lumen
Heat-stable Toxin (ST)
- Infection: Dysentery-like/Shigella-like Infection; Water diarrhea with WBCs
- Infective dose: >10^6
- Direct transmission via fecal-oral route
EIEC: ENTEROINVASIVE E. coli
E coli strain. Produces dysentery with direct penetration, invasion and destruction of the intestinal mucosa
EIEC - ENTEROINVASIVE E. coli
- Infection: Infantile Diarrhea
- Stool typically contains large amount of mucus but apparent blood is not
present - Lacked the toxins of ETEC and lacks the invasiveness of EIEC
EPEC: ENTEROPATHOGENIC E. coli
Also known as Verotoxic E. coli (VTEC) / STEC
EHEC: ENTEROHEMORRHAGIC
Infection: Hemorrhagic colitis, HUS, Bloody diarrhea without WBC
- Associated with ingestion of poorly cooked meats
EHEC
Produces SHIGA LIKE TOXIN
EHEC/EIEC
A toxin
Identical to Shiga toxin produced by S. dysenteriae Can be neutralized by antibodies to Shiga toxin
Verotoxin I
A toxin Biologically similar but immunologically different from Shiga toxin and Verotoxin I
Verotoxin II
Virulence factors of EHEC
Verotixon I
- (identical to shiga like toxin, can be neutralized with antibodies to shiga toxin)
Verotoxin II
- biologically similar but immunologically different from shiga toxin and verotoxin 1
Colorless on SMAC (sorbitol MacConkey Agar)
EHEC
What E. coli strain did Brianne Kinner suffer from?
Where did she get it from?
EHEC
Jack in the Box burger
serotype of EHEC associated with hemorrhagic diarrhea and HUS
0157:H7