Microbiology: Bacterial Flashcards Preview

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Flashcards in Microbiology: Bacterial Deck (241)
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1

Two toxins produced by C. difficile:
What kind of toxin? What is its function?

Toxin A = enterotoxin = exotoxin, binds brush border.
Toxin B = cytotoxin = destroys enterocyte cytoskeleton -> pseudomembranous colitis.

2

Two antibiotics especially associated with C. diff:

Clinda
Amp

3

Treatment for C. diff:

Metronidazole
ORAL vanc

4

Dx of C. diff:

Toxin in stool

5

Most common E. coli strain causing bloody diarrhea:

Enteroinvasive

6

Treatment for dysentery caused by E. coli:

Fluoroquinolones, TMP-SMX

7

Two toxins produced by enterotoxigenic E. coli:
Second messenger inside the cell for action of each?

Heat labile = cAMP increase = watery diarrhea like cholera
Heat stable = cGMP increase

8

Cause of traveler's diarrhea ("Montezuma's revenge"):

Enterotoxigenic E. coli

9

E. coli strain causing diarrhea in daycare:

EPEC

10

Causes HUS:

Enterohemorrhagic E. coli
Usually 0157:H7

11

Triad of HUS:
Explain how this happens:

Anemia
Thrombocytopenia
Acute renal failure
Shiga-like toxin from EHEC 0157:H7 damages endothelium, which swells, cuts off blood flow to the kidney. Narrow vessels shear RBC -> mechanical hemolysis. Damaged endothelium consumes the platelets -> thrombocytopenia.

12

Most E. coli ferment this sugar:
Which one does not?

Sorbitol
EHEC does not ferment sorbitol

13

Tx for HUS:

Supportive only.
Do not give abx.

14

Two E. coli strains causing dysentery:

Enteroinvasive
Enterohemorrhagic

15

E. coli strain causing watery diarrhea:

Enterotoxigenic

16

How would you distinguish EHEC from other forms of E. coli on culture?

It does not ferment sorbitol. The others do.

17

Organism responsible for causing staghorn calculi:

Proteus

18

Urease-positive, ammonium-Mg-phosphate stones:

Proteus

19

Common cause of osteomyelitis in sickle cell patients:

Salmonella

20

Four A's of Klebsiella:

Aspiration pneumonia
Alcoholics
Abscesses in lungs and liver
di-A-betics

21

Mucoid colonies, lobar pneumonia in a diabetic:

Klebsiella

22

Flagellated organism, hematogenous dissemination, produces H2S:

Salmonella

23

Very virulent organism, frequently causes bloody diarrhea, human and primate but not pet reservoirs:

Shigella

24

Associated with Reiter syndrome:

Shigella

25

Rose spots on abdomen:

Salmonella typhi

26

Carried in the gallbladder, found only in humans:

Salmonella typhi

27

Which organism ferments lactose: Salmonella or Shigella?

Trick question.
Neither.

28

Which organism produces H2S: Salmonella or shigella?

Salmonella

29

Which organism produces a monocytic response: Salmonella or Shigella? A PMN response?

Monocytes = Salmonella
PMNs = Shigella

30

Leading cause of bloody diarrhea in the US:

Campylobacter