Flashcards in Gram Neg Pathogens Pt 2 Deck (18):
Toxin-Producing Bacterial Pathogens:
1. Bacteria types
2. Infection location
3. Stool effects
1. Vibrio spp., Entertoxigenic E. coli
2. Small intestine
3. Lots of watery stool, no blood, no leukocytes, no tissue damage
Main Vibrio species. Causes diarrhea.
V. Cholerae ("Cholera gravis")
Virulence factors of V. Cholerae:
2. Pili to adhere to mucosal tissue
3. Cholera toxin- phage encoded
V. Cholerae gives off Ctx which enters cell and binds to ______, keeping it running, leading to cAMP overproduction and Cl over excreted from cell -> diarrhea.
E. Coli has a similar affect.
Adenylyl Cyclase (AC)
Responsible for 30-45% of traveler's diarrhea. Large infectious dose. Colonization factor antigens (cfa) on fimbrae help with adherence.
ETEC: Enterotoxigenic E. coli
ETEC produces 2 toxins responsible for disease:
1. Heat-labile toxin (LT): activates AC (like V. Cholerae)
2. Heat-stable toxin (ST): activates GC -> increased cGMP -> increased Cl release -> diarrhea
Treatments for secretory diarrhea:
1. Oral rehydration (sugar, salt, water)
2. Antibiotics can reduce severity
______ and _____ are "Hybrid" misfits of toxin-producing bacteria because they infect the lower small and upper large intestines, colonization causes effacing lesions, and the latter causes blood in stool
Enteropathogenic E. coli (EPEC)
Enterohemorrhagic E. coli (EHEC)
Hamburger pathogen. Produces shiga-like toxin that can lead to hemolytic uremic syndrome (HUS)
Intimate Adherence (attaching and effacing lesion) stages:
1. Bundle-forming pili (Bfp) assist in long distance adherence
2. Syringe-like secretion system injects Tir into host cell
3. Tir binds to intimin on E. coli -> pedestal formation
_____ causes diarrhea not by toxin production but instead by disruption of absorption/tight junctions
Most common form of bacterial infection of an organ system (minus mouth), and most frequent cause of doctor's visits (minus dentists). Mostly caused by E. coli.
Urinary Tract Infection (UTI)
Uncomplicated vs. Complicated UTI
1. Normal defense mechanisms intact
2. No recent hospitalizations
3. Disease limited to lower urinary tract
1. Structural abnormality in urinary tract
2. Recent hospitalization
3. Disease probably spreads to kidneys
Causes UTI. More severe than E. coli induced UTI.
Proteus Mirabilis (P. Mirabilis)
Proteus can be diagnosed by:
Consistently alkaline urine
2. Trimethoprim-sulfamethoxazole (TMP/SMX)
Large, mucous colonies due to large capsule. Related to pneumonia.