Flashcards in Enterobacteriaceae I Deck (40)
Are enterobacteriaceae gram+ or -?
What are antibodies formed against in enterobacteriaceae?
O antigen of LPS
What part of LPS is responsible for toxicity?
Lipid A (causes fever, diarrhea, shock)
Where is the H antigen located?
Where is the K antigen located?
(causes UTI, invasive disease)
What are the 7 virulence factors for enterobacteriaceae?
1) Endotoxins (LPS)
2) Capsule (no phagocytosis)
3) antigenic phase variation
4) type III secretory system
5) sequestration of growth factors (ex: iron)
6) resistance to serum killing
7) antimicrobial resistance
Are enterobact obligative or facultative?
What key enzyme are enterobact NEGATIVE for?
What is the energy source for enterobact?
reduce nitrate to nitrite
Do all bacteria ferment lactose?
NO, some do and some don't
What is special about macconkey agar?
only gram NEGATIVE grow on it
What color do lactose fermenters turn on macconkey agar?
Is the normal flora in our body lactose positive or neg?
positive (streak a stool sample and if everything is purple, no infection)
What are the 7 tribes of enterobacteriaceae?
What is the most common enterobacteriaceae isolated from human infection?
Where is E. coli found in the environment?
if it is found in water, it is indicative of fecal contamination
What are 6 clinical syndromes that E. coli can cause?
1) gram negative sepsis
3) wound infection
4) pneumonia in IC hospitalized patients
5) meningitis in neonates
What are the 5 strains of E. coli causing gastroenteritis?
1) Enterotoxigenic (ETEC)
2) Enteropathogenic (EPEC)
3) Enteroinvasive (EIEC)
4) Enterohemorrhagic (EHEC)
5) Enteroaggregative (EAggEC)
What strain of E. coli is associated with Traveler's diarrhea? (profuse watery diarrhea)
What strain of E. coli is associated with infantile diarrhea?
EPEC (no gross blood)
What kind of E. coli is associated with blood, mucus, and many leukocytes in the stool? And tenesmus
EIEC (invade epithelial cells)
What kind of E. coli is associated with bloody diarrhea without WBCs? no fever
EHEC (caused by O157:H7)
What kind of E. coli is associated with watery diarrhea with blood and mucus, less commonly associated with abdominal pain?
What is the most common Shiga Toxin Producing E. coli (STEC)?
How is STEC transmitted?
feces of cattle, deer, sheep
humans get it via food (undercooked ground beef), water or direct contact with infected patient
What 2 infections are associated with E.coli O157?
- Hemolytic Uremic Syndrome (HUS)
- Hemorrhagic Colitis
What 3 things are indicative of hemorrhagic colitis?
1) abdominal cramps, watery diarrhea, bloody discharge
2) no significant fever
3) absence of WBC in stool
What is the triad of symptoms in HUS?
- acute renal failure
- hemolytic anemia
What is the leading cause of renal failure in kids?
(preceded by bloody diarrhea)