Gram Negative Rods I Flashcards
Has the characteristic features of short thick rods and peritrichous flagella
Enterobacteriaceae
What is the oxidase classification of enterobacteriaceae?
Oxidase negative
Closely-related to enterobacteriaceae and has curved rods and polar flagella
Vibrio
What is the oxidase classification of Vibrio?
Oxidase positive
Curved or spiral shaped, and not closely-related to other enteric bacteria
Campylobacter
The Gram negative rods are transferred by the 4 F’s, which are
Feces, Fingers, Flies, and Food
-Oral-fecal transmission
What is the habitat for the gram negative rods?
Intestine
Intestinal defense that kills many bacteria
Gastric acid
Removes bacteria;
anti-motility drugs may prolong illness
Intestinal motility
Blocks colonization
by pathogens; Antibiotics may predispose to infection
Normal flora
What are the 4 cell types of the intestine?
Enterocytes, M cells, Macrophages, and Neutrophils
Specializedfortranscytosisofantigens to underlying lymphoid tissue
–many pathogens ‘hitch a ride’ to exit intestine
M cells
Mostly encoded by
Pathogenicity Islands, Plasmids and Phage genomes
Virulence factors
Emerges when the ‘correct’ constellation of virulence factor genes appears in a clone
Pathogen
For serotyping, what are the following antigens?
- ) H
- ) O
- ) K
- ) Flagella
- ) LPS
- ) Kapsule
Different serological types
(serotypes or serovars)
differ in
Virulence
Serotyping is useful for
Epidemiology
What are the three types of intestinal infections?
- ) Non-inflammatory
- ) Inflammatory
- ) Penetrating
Bacteria in lumen
Non-inflammatory
Bacteria invade wall
Inflammatory
Bacteria get beyond intestinal wall
Penetrating
Watery diarrhea; no wbc (or lactoferrin) in feces; no fever
Non-inflammatory enteritis
What are two virulence factors for non-inflammatory enteritis
Adhesins and exotoxins
Toxin deliberately secreted against endotoxin
Exotoxins
Exotoxins stimulate
Salt transport
Toxin-producing E. Coil that can cause non-inflammatory enteritis
Vibrio Cholerae
There is a vibrio cholerae endemic in
SE Asian
The first 6 pandemics of Vibrio cholerae were caused by strains of serotyping
O1
The classic O1 biotype is replaced by
El Tor
In the 7th vibrio cholerae pandemic, the classic O1 biotype was replaced by
O139
Non-pathogenic strains of Vibrio cholerae are common world-wide in
Salt/brackish water
Causes massive diarrhea:
-up to 20 liters stool per day
Vibrio Cholerae disease
What are the treatments for Vibrio cholerae disease?
Fluid replacement and anti-biotics (tetracycline or ampicillin)
What type of agars can we use to culture Vibrio cholerae
Blood, chocolate, MacConkey, and TCBS agar
Adds ADP-ribose group to Gs protein
A subunit of Cholera toxin
Permanently activates Gs which stimulates adenyl cyclase
Cholera toxin
High cAMP causes high
Cl- transport
The transporter for these Cl- ions is
CFTR
High salt concentration in intestinal lumen produces
Osmotic inflow of water
The virulence of Vibrio cholerae is from a toxin coregulated
Pilus (type IV pilus)