Enteric Bacteria Flashcards
Enteric bacteria is what shape and gram stain?
Gram - bacilli
Are enteric bacteria members in animal or human flora?
Both
_______ bacteria:
Some are members of commensal groups that have become pathogenic due to acquired virulence factors like toxins from plasmids, bacteriophages or “pathogenicity islands”
Enteric bacteria
Most can be motile with peritrichous flagella (H-antigen)
Enteric bacteria
Most have surface pili: fimbriae for adherence and sex pili for plasmid conjugation
Enteric bacteria
Do Some species of enteric bacteria have capsules?
Yes
All enteric bacteria have outer-membrane ______ with enterobacterial common antigen and serotype-specific O-antigen
LPS(heat-stable endotoxin)
All enteric bacteria have outer-membrane LPS(heat-stable endotoxin) with _______ and ________
enterobacterial common antigen and serotype-specific O-antigen
When bacteria have a toxin like cholera toxin, you get _____ diarrhea
watery diarrhea
When also have a toxin like Shiga toxin, you get _____ in diarrhea
blood in diarrhea
When also have inflammation and neutrophils:get _____ in diarrhea = dysentery
pus in diarrhea
____ bacteria:
Transmission:•person-to-person•“seven F’s”= feces, food, fluids, fingers, flies, fomites, and fornication
Enteric bacteria
What are the 7 F’s seen in transmission of enteric bacteria?
feces food, fluids, fingers, flies, fomites, fornication
LPS Outer-and inner-core sugars are the _____ antigen
enterobacterial common antigen
_____ is also known as the heat-stable enterotoxin
LPS
________ = chromosomal location with multiple virulence factors and toxin genes, readily transferable together by conjugation.Example: uro-pathogenic E.coli
pathogenicity island
_______: is present in many bacteria like Yersinia, Salmonella, Shigella, enteropathogenic EPEC (E.coli); also present in other species like Pseudomonas and Chlamydia): 20-protein system that looks like a short, hollow flagellum (“needle”) to inject a variety of species-specific toxins into host cells
Type III secretion system
Translocated intimin receptor and intimin are transmitted via ___________
Type III secretion system
_____ and _______ are transmitted via Type III secretion system
Translocated intimin receptor and intimin
_______ Transmission:
•person-to-person
•contaminated food
•human and animal feces(no hand washing; insect vectors)
E. Coli
The following virulence are characteristic of _______:
Heat-labile enterotoxin LT
Shiga toxin
E. Coli
_______: ADP-ribosylation of G protein ►cAMP ►loss of water + electrolytes ►watery diarrhea (e.g. foodborne enterotoxigenic ETEC E.coli) Traveller’s diarrhea (E. Coli)
heat-labile enterotoxin “LT”(cholera-like AB-exotoxin)
_______: inactivation of 60S ribosome subunit by removal of a specific adenine base from a nucleotide of 28S rRNA ►stop translation ►cell death ►bloody diarrhea (e.g. foodborne enterohemorrhagic EHEC E.coliO157:H7)In addition:►hemolytic uremic syndrome ►kidney damage (E. Coli)
Shiga toxin(AB-exotoxin cytotoxin)
In _______ this set of symptoms “diarrhea with blood”is combined with intestinal cell invasion, apoptosis and neutrophilia (►“pus”)to define “dysentery”.
Shigella dysenteriae
_____ E. Coli, the clinical signs are bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome
- Treatment: replenish fluids (antibiotics are contraindicated)
EHEC (O157:H7)
_____ E. Coli, the clinical signs are cystitis; 70-90% E.coli
UroPathogenic
_____ are taken up by M cells and transported beneath the epithelium. (Shigella dysenteriae)
Shigella
_____ take up shigellas, die and release the bacteria replenish fluids (Shigella dysenteriae)
Macrophages
The bacteria enter the inferior and lateral (apical) aspects of the epithelial cells by inducing ________ (Shigella dysenteriae)
endocytosis
The endosomes are quickly lysed leaving the Shigellas free in the ______ (Shigella dysenteriae)
cytoplasm
_______ filaments quickly form a tail pushing the shigellas into the next cell (Shigella dysenteriae)
Actin filaments
Shigellas multiply in the ____ and the infection extends to the next cell (Shigella dysenteriae)
cytoplasm
Infected cells die and slough off. Intesen response of acute inflammatory cells (neutrophils), bleeding and abscess formation induces ______ (Shigella dysenteriae)
Apoptosis
The following virulence factors are characteristic of _______:
Shiga toxin
Cell invasion
(Shigella dysenteriae)
Transmission of ______ is via fecal-oral route; sometimes by fecally contaminated food or water; humans generally the only source
(Shigella dysenteriae)
_______ causes enteric fever, human reservoir, typhoid, and high mortality; typically poultry reservoir
Salmonella
The following virulence factors are characteristic of _______:
ØType III secretion induces enteric epithelial uptake via M cells
Øintracellular endosome growth in macrophages: secretes protein that prevents phagosome-lysosome fusion
-in S.typhi serovars:
Øthrough macrophages: invasive into different tissues and organs
Ødestruction of Peyer’s Patches ►intestinal rupture
Salmonella
Is salmonella acid labile or acid resistant?
Acid labile
- M cell uptake through ruffles: transport through epithelial layer.
- Electrolyte release to lumen (diarrhea/gastroenteritis).
- Release of inflammatory exudate.
- Transport to lymph nodes / transient bacteremia
Salmonella
_____ is seen by the following symptoms:
- Diarrhea , hemorrhage, and perforation of small intestine
- Cholecystitis of gall bladder
- Fever, and other affection of organs via speticemia
Typhoid fever
Typhoid fever is carried in what organ?
Gallbladder
What is gram stain and shape of Vibrio cholerae?
Gram - vibrio
Gram− vibrio(curved rods) (salt tolerant)found in estuaries and marine environments (e.g. in crabs)
Vibrio cholerae
The following virulence factors are characteristic of _______:
Øtoxin co-regulated pilus (tcp)
Øcholera toxin(heat-labile exotoxin “LT”)
Øan additional toxin “ST”
Neuraminidase
Vibrio cholerae
_____ is a virulence factor used in adhesion to small intestinal epithelia (Vibrio cholerae) (toxin is phage CTXφ-encoded and regulated by pilin-regulating chromosomal gene)
Øtoxin co-regulated pilus (tcp)
_____ is a virulence factor: protein A causes cAMP rise + watery diarrhea (Vibrio cholerae)
cholera toxin(heat-labile exotoxin “LT”)
_____ is a virulence factor used to increase cholera toxin binding (Vibrio cholerae)
Neuraminidase
____ production is induced within the intestine, while production in other environments appears to be minimal (Vibrio cholerae)
TCP
_____ and ____ encode the proteins that comprise cholera toxin (Vibrio cholerae)
ctxA and ctxB
What strain of cholera is the common epidemic strain?
Serovar O1
What strain of cholera is the newer strain?
Serovar O139 with Capsule
Is there a cholera vaccine?
Yes
What is the common prevention of cholerae?
chlorination of water
_______: disease is self-limiting as intestinal cells with surface bacteria are shed
Cholera
The epidemiology of ______ is fecal transmission in developing countries under-cooked coastal crabs
Cholera
___ bacteria is more commonly causes gastroenteritis than E coli and salmonella
Campylobacter jejune
Zoonosis: animal reservoir (intestinal)
Transmission: contaminated food (poultry, milk)(e.g. in >89% of raw chicken)
Disease: gastroenteritis, diarrhea, dysentery
Disease resolves without treatment in <1 week
-Creates protective immunity
Campylobacter jejune
Growth in intestinal tract:
§invade intestinal epithelial cells or grow below
epithelial layer.
§inflammatory response
Campylobacter jejune
