Enterobacteriaceae Flashcards
1
Q
Enterobacteriaceae (4):
A
- Gram negative rods.
- LPS in cell wall.
- Ferment glucose.
- Oxidase negative
2
Q
Enterobacteriaceae that ferment lactose (5):
A
Occurs: - Klebsiella. - Escherichia - Enterobacter Slowly: - Serratia - Vibrio
3
Q
Enterobacteriaceae virulence factors (7):
A
- Endotoxin (LPS - highly immunogenic).
- Capsule.
- Antigenic phase variation.
- Type III secretion system.
- Sequestration of growth factor.
- Resistance to serum killing (compliment).
- Antimicrobial resistance.
4
Q
Diseases caused by E. coli (5):
A
- Gastroenteritis.
- Hemolytic-uremic syndrome.
- UTI.
- Neonatal meningitis.
- Septicemia.
5
Q
Five major E. coli groups (5):
A
- ETEC
- EPEC
- EIEC
- EAggEC
- EHEC
6
Q
ETEC (6):
A
- 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
Q
EPEC (7):
A
- 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
Q
EHEC (4):
A
- 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
Q
EIEC (6):
A
- 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
Q
EAggEC (4):
A
- Adhesins not characterized.
- Non-invasive.
- Produce ST-like toxin and a hemolysin.
- Persistent diarrhea in young children without immunization, no fever.
11
Q
Most common cause of UTI:
A
E. coli
12
Q
Salmonella spp (4):
A
- Common in GI tract of animals but not humans.
- Do not ferment lactose.
- Produce H2S.
- Facultative intracellular growth.
13
Q
Diseases caused by salmonella spp (4):
A
- Gastroenteritis.
- Typhoid (enteric) fever (s. typhi).
- Bacteremia.
- Localized infections in other sites (usually immunocompromised).
14
Q
Typhoid fever (6):
A
- 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
Q
Enterocolitis (4):
A
- 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.