Enterobacteriaceae Flashcards Preview

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Flashcards in Enterobacteriaceae Deck (18):
1

Enterobacteriaceae (4):

- Gram negative rods.
- LPS in cell wall.
- Ferment glucose.
- Oxidase negative

2

Enterobacteriaceae that ferment lactose (5):

Occurs:
- Klebsiella.
- Escherichia
- Enterobacter
Slowly:
- Serratia
- Vibrio

3

Enterobacteriaceae virulence factors (7):

- Endotoxin (LPS - highly immunogenic).
- Capsule.
- Antigenic phase variation.
- Type III secretion system.
- Sequestration of growth factor.
- Resistance to serum killing (compliment).
- Antimicrobial resistance.

4

Diseases caused by E. coli (5):

- Gastroenteritis.
- Hemolytic-uremic syndrome.
- UTI.
- Neonatal meningitis.
- Septicemia.

5

Five major E. coli groups (5):

- ETEC
- EPEC
- EIEC
- EAggEC
- EHEC

6

ETEC (6):

- Plasmid-mediated.
- Non-invasive.
- Fimbrial adhesins, CFA I and II.
- Heat labile (LT) and heat stable (ST) enterotoxins.
- Watery diarrhea in infants and traveler's diarrhea.
- No inflammation, fever or cell cytotoxicity.

7

EPEC (7):

- Non-fimbrial adhesion.
- Moderately invasive.
- Does not produce LT or ST.
- Attachement-effacement.
- Bundle forming pilus (Bfp).
- Destruction of microvilli.
- Infantile diarrhea, some inflammation, no fever.

8

EHEC (4):

- Moderately invasive.
- Does not produce LT or ST.
- Produces shiga-like toxin (SLT) - cytotoxic to intestinal villi and colon epithelial cells.
- Pediatric diarrhea, copious bloody discharge, intense inflammation and hemolytic uremia.

9

EIEC (6):

- Non-fimbrial adhesions.
- Invasive.
- Entry site is the M cell.
- Does not produce shiga toxin.
- Dysentery-like diarrhea (mucous, blood), severe inflammation, fever.
- Very large plasmid.

10

EAggEC (4):

- Adhesins not characterized.
- Non-invasive.
- Produce ST-like toxin and a hemolysin.
- Persistent diarrhea in young children without immunization, no fever.

11

Most common cause of UTI:

E. coli

12

Salmonella spp (4):

- Common in GI tract of animals but not humans.
- Do not ferment lactose.
- Produce H2S.
- Facultative intracellular growth.

13

Diseases caused by salmonella spp (4):

- Gastroenteritis.
- Typhoid (enteric) fever (s. typhi).
- Bacteremia.
- Localized infections in other sites (usually immunocompromised).

14

Typhoid fever (6):

- S. typhi and S. paratyphi.
- 6-30 days incubation.
- Initial symptoms: fever, HA, malaise and anorexia.
- Starts in small intestine through peyer's patches, then spread to phagocytes of liver, gallbladder and spleen.
- Survival in the phagosomes in phagocytic cells - carrier state.
- Transmitted only by humans.

15

Enterocolitis (4):

- Invasion of epithelia and sub-epithelial tissue of the small and large intestines.
- PMN response limits to the gut and adjacent lymph node.
- Infective dose very high.
- Gastric acid important host defense.

16

Shigella spp (7):

- Non-lactose fermenting.
- Gram-negative rods.
- Do not produce H2S.
- Non-motile.
- Produce no gas fermenting glucose.
- Shiga toxin.
- No animal reservoir.

17

Reiter's Syndrome (3):

- Arthritis, conjunctivitis and urethritis.
- Appear after intestinal infections by one of the intestinal pathogens.
- Most male, HLA-B27.

18

Pathogens that cause Reiter's syndrome (5):

- Shigella.
- Yersinia enterocolitica.
- Salmonella.
- Klebsiella pneumoniae.
- Campylobacter.