Gastrointestinal Organisms Flashcards
Physical characteristics of enterobacteriaceae?
Facultatively anaerobic
G- Rods
Enterobacteriaceae use what type of secretion system?
3
What antigens are used to type Enterobacteriaceae.
O, H, K/Vi
Biochemical tests for Enterobacteriaceae?
IMViC
Carbohydrate fermentation
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?
Enterotube
Three most common causes of foodbourne outbreaks?
Salmonella
Campylobacter
Shigella
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
Enteric/Diarrheal Disease
Urinary Tract Infections
Sepsis/Meningitis
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
P
What does EPEC stand for?
What does it do?
Enteropathogenic
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?
Enterohemorrhagic
Bloody diarrhea without fever
Hemolytic-Uremic Syndrome
How does EHEC mediate medical effects?
Verotoxin (Shiga-like) – AB toxin protein synthesis inbititor
What is Hemolytic-Uremic Syndrome?
Treatment?
Uremia and organ failure due to glomerular damage
NO anti-biotics – they induce stx gene
What is EIEC?
Medical effects?
Enteroinvasive
Bloody fever with fever
EIEC is Indistinguishable from…
Shigella dysenteriae type I
Factors produced by EIEC?
Invasive colonization factors
What is EAEC?
Medical Effects?
Enteroaggregative
Noninflamatory pediatric diarrhea caused by biofilm development
E. coli K1 is a major cause of…
neonatal meningitis
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?
S. enterica
It is important to distinguish what two categories of salmonella enterica?
S. typhi and paratyphi vs. all others