Gram Neg Pathogens Pt 2 Flashcards Preview

D1S U1 Microbiology > Gram Neg Pathogens Pt 2 > Flashcards

Flashcards in Gram Neg Pathogens Pt 2 Deck (18):
1

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

2

Main Vibrio species. Causes diarrhea.

V. Cholerae ("Cholera gravis")

3

Virulence factors of V. Cholerae:

1. Flagella
2. Pili to adhere to mucosal tissue
3. Cholera toxin- phage encoded

4

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)

5

Responsible for 30-45% of traveler's diarrhea. Large infectious dose. Colonization factor antigens (cfa) on fimbrae help with adherence.

ETEC: Enterotoxigenic E. coli

6

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

7

Treatments for secretory diarrhea:

1. Oral rehydration (sugar, salt, water)
2. Antibiotics can reduce severity

8

______ 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)

9

Hamburger pathogen. Produces shiga-like toxin that can lead to hemolytic uremic syndrome (HUS)

EHEC

10

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

11

_____ causes diarrhea not by toxin production but instead by disruption of absorption/tight junctions

EPEC

12

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)

13

Uncomplicated vs. Complicated UTI

Uncomplicated:
1. Normal defense mechanisms intact
2. No recent hospitalizations
3. Disease limited to lower urinary tract

Complicated:
1. Structural abnormality in urinary tract
2. Recent hospitalization
3. Disease probably spreads to kidneys

14

Causes UTI. More severe than E. coli induced UTI.

Proteus Mirabilis (P. Mirabilis)

15

Proteus can be diagnosed by:

Consistently alkaline urine
Urease production

16

UTI Treatments

1. Antimicrobials
2. Trimethoprim-sulfamethoxazole (TMP/SMX)

17

Large, mucous colonies due to large capsule. Related to pneumonia.

Klebsiella

18

Among most prevalent Gram-negative GI bugs. Transmitted by oral-to-oral and fecal-to-oral contact. Slow bacterium. Can lead to many gastric diseases. Treated by proton pump inhibitor to decrease gastric acid secretion.

Helicobacter pylori