Flashcards in Gastrointestinal Organisms Deck (87)
Physical characteristics of enterobacteriaceae?
Enterobacteriaceae use what type of secretion system?
What antigens are used to type Enterobacteriaceae.
O, H, K/Vi
Biochemical tests for Enterobacteriaceae?
Packaged Test Kits
What does IMViC stand for?
Indole methyl red Voges-Poskauer citrate
How are carbohydrate fermentations occur?
Use MacConkey's Agar (Lactose)
Lac+ are coliforms
Name for packaged test kits for Enterobacteriaceae?
Three most common causes of foodbourne outbreaks?
Relationship of Enterobacteriaceae to endocrine system
Gut bacteria can respond to stress-induced neuroendocrine hormone levels
How do bacteria avoid immune response?
Subvert response to avoid detection
How can E. Coli be detected on agar?
Copious acid production detected by green metallic sheen on EMB agar
Three general clinical syndromes that come from E. Coli
Urinary Tract Infections
Most common extraintestinal E. Coli infections?
UTI via UPEC
Two ways that E. coli may lead to UTI
Acquire from proximity of anus to urethral meatus
From increased sexual activity (honeymoon cystitis)
UPEC is associated with the __ Pilus
What does EPEC stand for?
What does it do?
Intimin attached protein, bundle formed pili
Efface small intestine microvilli and inhibit water uptake
Medical effects of EPEC?
Who gets it?
Watery, self-limiting diarrhea
Esp. Young Children
What does ETEC stand for? Nickname?
Medical side effects?
Enterotoxigenic. "Traveler's Diarrhea"
Watery diarrhea, increased gut motility, ab cramps
ETEC is associated with what pili?
CFA adhesion pili for brush-border membrane
What toxins are produced by ETEC?
2 LT Toxins (LT1 like cholera, higher cAMP)
2 ST toxins (activates cGMP)
What does EHEC stand for?
Medical side effects?
Bloody diarrhea without fever
How does EHEC mediate medical effects?
Verotoxin (Shiga-like) -- AB toxin protein synthesis inbititor
What is Hemolytic-Uremic Syndrome?
Uremia and organ failure due to glomerular damage
NO anti-biotics -- they induce stx gene
What is EIEC?
Bloody fever with fever
EIEC is Indistinguishable from...
Shigella dysenteriae type I
Factors produced by EIEC?
Invasive colonization factors
What is EAEC?
Noninflamatory pediatric diarrhea caused by biofilm development
E. coli K1 is a major cause of...
Why is E. coli K1 not a good antibody target?
Molecular mimic of host NCAM receptors
Who is E. coli K1 especially dangerous to?
low birthweight infants
Salmonella grows on what medium?
Selective media with bile salts (deoxycholate)
How is salmonella classified?
By serotype (O, H, Vi(K))
All salmonella belong to what species?
It is important to distinguish what two categories of salmonella enterica?
S. typhi and paratyphi vs. all others
Three types of disease caused by salmonella enterica?
Typhoid Fever is cause by what forms of salmonella?
S. Typhi or Paratyphi
Medical effects of Typhoid Fever?
Invasive disease - reaches bloodstream through mucosa
Disseminates via macrophage to spleen, liver, GB
Death from intestinal hemorrhage
Who gets bacteremia/septicemia from Salmonella?
Medical effects of salmonella enterocolitis/gastroenteritis?
Nausea, Vomiting, Diarrhea, Fever Common
May colonize GB and shed for weeks
In what food products is Salmonella enterocolitis/gastroenteritis spread?
Eggs and Poultry Products
Four ways in which salmonella enterocolitis/gastroenteritis is spread?
Fecally contaminated water
Endemic in Eggs/Poultry
Crops fertilized by excreta
Describe pathogenesis of salmonella.
Binds brush border to invade gut epithelil cells
Invade deep tissues/bloodstream
Produce cytotoxic enterotoxin
Type of toxin? Effect of components?
A1 -- ADP-ribosylates G-protein
A2 -- damages DNA and halts cell replication
Shigella can also grow in _____ by ______
Efflux pumps and DNA repair
Uses Phospholipids as a C-source
Shigella grows on ____ agar
Clinical presentation of shigella?
Onset with Acute Watery Diarrhea
2 days later - blood and mucus into stool
Subsides in about a week, but lethal dehydration
How is Shigella spread?
Infection via fecal-oral route
Shigella is most common in what population?
How is Shigella spread?
Food, Fingers, Feces, Flies
Explain the pathogenesis of shigella.
- Phagocytosed and transmitted through M cells
- Engulfed by macrophages in lamina propria
- Lyse phagolysosome and replicate in cyto
- Macro apop. -- release IL1 and cytos that make junctions permeable
- Induces basal membrane phagocytosis
How does shigella spread?
How does shigella secrete invasion factors?
Type III secretions
How does Shiga enterotoxin kill?
Disruption of protein synthesis
Unique staining seen in yersinia?
Bipolar staining (Wright-Giemsa, Wayson's)
How does Yersnia bind?
Yersnia uses what secretion system?
What antigens allow intracellular growth?
V and W antigens
Yersnia pestis is most commonly known as...
Three types of yersnia pestis?
Symptoms of Bubonic yersnia pestis?
1-8 day incubation
Malaise, headache, vomiting
Painful Buboes in groin and other lymph nodes
What are buboes full of?
What diseases with buboes must yersnia be distinguished from?
Bacteria and Pus
Describe septicemic yersnia pestis
Primary or secondary to bubonic
Sepsis, Purpura, DIC, Necrosis
Describe pneumonic yersnia pestis?
Primary or Secondary
Primary form inhalation, secondary from intravascular dissemination
Hemoptysis, bilateral alveolar involvement
Outlook for pneumonic yersnia pestis
Virtually 100% fatal within 24 hours
How is yersnia pestis spread?
Typically spread by vector (rat flea)
Reservoirs are Deermice and ground squirrels
How does yersnia pestis effect fleas?
Toxin blocks flea's gut, forms blood clot
When flea bites again, clot is regurgitated into host
Aside from natural transmission, yersnia pestis can be seen as...
A Warfare Agent
Pathogenesis of yersnia pestis?
- Type III Secretory System injects toxins
- Inhibits MAP kinase signalling pathway (YopJ)
- No cytokine production, no cell replication
- Inhibits Phagocytosis (YopE)
- Inhibits Platelet Aggregation (YopM)
How is yersnia pestis controlled?
Insectiside to kill fleas
Vaccine that must be boosted every 6-12 months
How do you treat a yersnia patient treated?
Oral tetracycline for exposed and asymptomatic
I.M. Streptomycin once symptoms
Pneumonic plague treatment is rarely successful
Symptoms with Y. enterocolitica
-- Enterocolitis with intestinal abscess -- bloody diarrhea, abdominal cramps, fever
-- Mesenteric adenitis
Reservoirs for Y. enterocolitica?
How is Y. enterocolitica spread?
Feces, Contaminated drinking water/milk
How are Y. enterocolitica and Y. pseudotuberculosis treated?
Ceph III, SxT
Describe klebsiella pneumonia medical effects.
Small Percent of Pneumonias
Extensively hemorrhagic and necrotizing (currant jelly sputum)
Treatment success of klebsiella pneumonia?
Describe the pathogenesis of klebsiella granulomatis
Describe sores in klebsiella granulomatis.
Painless anal or genital sores
Gradually progressive lesions destroy large areas of tissue
How is proteus mirabilis seen on agar?
Proteus mirabilis is associated with what condition?
Proteus miribilis causes what condition? How?
How is Serratia marcescens usually acquired?
Pneumonia, Bacteremia, Endocarditis
How are enterobacteria usually treated, generally?
Isolate and clean sources
Ampicillin, Cephalosporins, Quinolines, Sulfa
For a uncomplicated UTI, Don't use_______.
1st choice --
2nd choice --
Don't -- Flouroquinolone
1st -- Bactrim (SxT)
2nd -- Fosfomycin
Why don't you want to use f'quinolones for UTI?
It mimics a quorom sensing signal, can lead to film formation
Typically you would treat Traveller's Diarrhea with ____
You would treat campylobacter with _____
There has recently been increased appreciation for the importance of restoring normal _______ in GI disorders