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63 Cards in this Set
- Front
- Back
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What are the biochemical characteristics of Ecoli?
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gram negative rod
90% lactose + indole +!!! motile |
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What are the 4 serotype antigens of e. coli?
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O
H K F |
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What is the O Ag for E. coli?
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somatic antigen
LPS oligosaccharide side chain |
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What is the H Ag for E. coli?
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flagellar Ag
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What is the K Ag for E. coli?
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capsular Ag
acidic polysaccharides |
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What is the F Ag for E. coli?
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fimbrial antigens (protiens)
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What causes 90% of UTIs in anatomically normal unobstructed urinary tracts?
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e. coli
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What is usually present in stool and colonizes periurethral adn vaginal areas?
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UPEC - uriopathogenic strains of e. coli
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Bacteriuria?
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E.coli ascends to the bladder
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Cystitis?
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invasion of mucosa, inflamation
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Pyelonephritis?
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passage up ureters and replication in teh renal pelvis and parenchyma
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UPEC possesses a pathogenicity island that...
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is located on the same chromosome as a PI encoded by e.coli causing diarrhea
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Adhesions associated with urinary tract e. coli infections
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Type I finbriae, pili
FimH |
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Type I fimbriae, pili...
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mannose sensitive - recognizes cells that contain surface glycoprotiens with mannose
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FimH...
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adhesion!
allows colonization of intestinal, vaginal, urethral and bladder mucosal cells |
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Ecoli that cause kidney infections produce what?
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p or pap pili that bind to glycolipid on the surface of bladder and kidney cells
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Neonatal Meningitis
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synth K1 capsule
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What is K1 capsule?
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homopolymer of silic acid that is similar antigenically to fetal neuronal tissues that evade phagocytosis and complement adn cause meningitis
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K1 is immunologically and chemically identical to what?
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the capsular polysaccharide of N. meningitidis group B
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ALL e.coli causing diarrhea have...
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atleast one virulence determinatant carried on a plasmid
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Diarrhagenic e.coli has chromosomal virulence factors organized in clusters called
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pathogenicity islands
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diarrhagenic e. coli has individual traits that can be encoded on ...
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transposons ST
phage Stx 2 |
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What are the 3 phatogenic paradigms for diarrheagenic e. coli?
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1. enterotixin production
2. intracellular invasion 3. intimate adherace & membrane signaling |
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Colonization factors for ETEC?
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multiple protein fimbriae that are plasmid encoded
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What is the epidemiology of ETEC?
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associated with food/water
traveler's diarrhea |
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Clincial considerations for ETEC?
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abrupt onset of watery diarrhea with no blood
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What are the 2 toxins of ETEC?
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ST
LT |
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What is LT?
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toxin of ETEC
heat labile A:5B |
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What does the A subunit of ETEC LT toxin do?
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ADP-ribosylates Gs stim subunit of adenylate cyclase that elevates intracellular cAMP
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What is CFTR?
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in ETEC LT toxin
stim secretion of Cl- inhibition of Na absorption water efflux osmotic diarrhea |
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What is ST?
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toxin in ETEC
heat stable |
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What is ST in ETEC encoded on?
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plasmids and transposons
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What does ST do?
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ETEC toxin
binds guanylate cyclase to stim cGMP to make CFTR |
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What is the end result of ST toxin of ETEC?
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osmotic diarrhea due to CFTR same as LT toxin
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What is enteropathic e.coli associated with?
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infant diarrhea
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What group does EPEC belong to?
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intimate adherance and membrane signaling
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what is the major histopathology of EPEC?
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attaching and effacing lesion
-effacement of microvilli -intimate attatchment -cytoskeletal changes -pedestals |
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What is the diagnositic test for EPEC?
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FAS - fluorescent actin staining test
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Local adherence in EPEC?
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plasmid encoded bundle forming pili (bfp)
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Signal transduction in EPEC?
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change intracell Ca and release IP3 to P myosin light chain activation of PKC which causes inc perm of tight junctions and migration of polymorphonulcear leukocytes adn up reg of NF-kB to cause an inflammatory response
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Intimate adherence in EPEC...
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mediated by intimin encoded on the eae gene
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What does intimin do
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part of EPEC
binds to Tir |
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What is Tir?
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part of EPEC
delivered by type III P in euk intestinal cells causes pedestal formation |
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What does Wiskott-Aldrich Syndrome have to do with anything?
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family of proteins (WASP) and actin nucleating factor Arp2/3 cause pedestal formation
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What group is enterohemorrhagic e.coli a part of? (EHEC)
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intimate adherence and membrane signalling
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Hemorrhagic colitis HC is assoicated with?
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EHEC
consumption of undercooked hamburgers O157:H7 |
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Sporatic HUS is associated with?
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EHEC
fecal cytotoxin |
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Sx of enterohemorrhagic e. coli (EHEC)?
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severe crapmy ab pain
watery diarrhea followed by grossly bloody stool little or no fever |
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the really bad stuff associated with enterohemorrhagic e. coli (EHEC)...
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renal failure!
thrombocytopenia microangiopathic hemolytic anemia |
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Typically EHEC strains:
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produce Stx
A/E lesions 60-MDa plasmids |
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What is the histopathology of EHEC?
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hemorrhage & edema of lamina propria
thumbprinting pattern on barium enema focal necrosis, infiltrating neutrophils |
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cytotoxicity of EHEC could be neutralized by?
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antibodies to Stx 1
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The A subunit of shiga toxin is?
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RNA N-glycosidase
removes single adenine residue form teh 28S rRNA of eukaryotic ribosomes |
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The B subunit of the shiga toxin is?
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binds globotriasylceramide Gb3
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Why is there bloody diarrhea with HUS?
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toxins effect endothelia cells
receptor density onf renal cel contrib of LPS contrib of cytokines inflammatory response |
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Where is the reservoir for EHEC?
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intestinal tract of cattle
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What is EIEC?
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enteroinvasive e. coli
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what group is EIEC in?
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intracellular invasion
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Characteristics of EIEC?
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non-motile
lactose negative! related to shigella |
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What is the pathogenesis of enteroinvasive e. coli?
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epithelial cell penetration
lysis of endocytic vacuole intracellular multiplication move through cytoplasm invasion into adjacent cells |
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What causes the ulceration of the colonic mucosa in EIEC?
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strong inflammatory response
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Clinically, what does enteroinvasive ecoli look like?
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period of watery diarrhea occassionally followed by teh onset of scanty stool containing blood and mucus
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What is the epidemiology of EIEC?
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infectious dose is higher than shigella
foodborne/water/person to person |
