ENTEROCOCCI

Question 1

Natural inhabitant of the intestinal tracts of humans and animals:

Answer 1

enterococci

Question 2

TRUE OR FALSE:
Enterococci can grow in extreme conditions.

Answer 2

TRUE. They can grow in alkaline pH, grows at 45C, and salt solution.

Question 3

Virulence factors:

Answer 3

extracellular serine protease, gelatinase, and cytolysin

Question 4

Species under Enterococci:

Answer 4

“GRAD FF”
E. gallinarum
E. raffinosus
E. avium
E. durans
E. faecalis
E. faecium

Question 5

Enterococci are identified based on:

Answer 5

1. produce acid in carbohydrate broth
2. produce acid from methyl-a-glucopyranoside (MGP)
3. hydrolyze arginine
4. tolerate 0.04% tellurite
5. utilize pyruvate
6. growth around 100ug efromycin acid disk

Question 6

Microscopy of Enterococci:

Answer 6

gram (+) cocci in pairs and long chains

Question 7

Culture media of Enterococci:

Answer 7

TSB or BHI with 5% sheep’s blood (routinely used)

Question 8

Selective media for contaminated specimens:

Answer 8

bile esculin azide agar, CNA agar, PEA, and cephalexin-aztreonam-arabinose agar

Question 9

Detected by its ability to grow in medium containing tellurite:

Answer 9

E. faecalis

Question 10

Detecting the growth of bacteria in the prescence of 40% bile and the ability to hydrolyze esculin:

Answer 10

bile esculin (BE) test

Question 11

Reagent of BE test:

Answer 11

esculin + 1-4% bile salt

Question 12

BE test (+) result:

Answer 12

black color complex in the agar (both enterococci and non-enterococci) within 48 hours

Question 13

6.5% NaCl test (+) result:

Answer 13

turbidity - enterococci (also PYR+)

Question 14

6.5% NaCl test (-) result:

Answer 14

non-enterococci

Question 15

Penicillin test:

Answer 15

resistant

Question 16

Growth factor required for E. faecalis:

Answer 16

cyanocobalamin (B12)