Stool cultures

Question 1

Routine and special request cultures

Answer 1

fresh stool < 2 hrs trasport to lab in a leak proof container
specimen more than 2 hours: must be transported in a cary-blair;

Question 2

C diff specimens

Answer 2

• submit fresh stool w/o added preservites or liquid
• refrigerate or freese within 2 hrs
• as the ph drops, stool cools and inactivates the toxin,
• rotovirus: refridgerate and test withing 72 hours or freeze

Question 3

selective media

Answer 3

allows certain types of bacteria to grow while inhibiting others with sugars, dyes. antib’s, salts. inhibitors

Question 4

differential media

Answer 4

differentiates closely related organisms

• ph indicators for carbohydrate fermentation
• H2S production
• hemolysis pattern

Question 5

Columbia CNA

Answer 5

selects for gram +

coliston, naladixic acid

Question 6

XLD

Answer 6

xylose-lysine desoxycholate

• shigella= red colonies
• salmonella= red colonies/ black centers

Question 7

SS agar

Answer 7

salmonella- shigella

• shigella- clear
• salmonella= clear colonies w/ black centers

Question 8

Hektoen

Answer 8

determines lactose fermenter with H2S production, inhibits Gram +

• shigella- lactose negative
• salmonella = lactose negative w/variable H2

Question 9

Maconkey

Answer 9

Gram negatives

• lactose fermenters?
• E. Coli = lactose fermenters

Question 10

CVA

Answer 10

Campy CVA: campy bacter

• wet tan colonies
• microphillic

Question 11

TCBS

Answer 11

thiosulfate- citrate- bile salts-sucrose

• used mostly for vibrio colonies
• V. parahemolyticus are blue/green colonies

Question 12

CIN

Answer 12

room temp

- mannitol positive bulls eye colonies

Question 13

EMB

Answer 13

eosin methylene blue

• used in some labs instead of MAC plates
• E. Coli: metallic green colonies

Question 14

brilliant green

Answer 14

selective for salmonella

Question 15

bismuth sulfite

Answer 15

salmonella

Question 16

enrichment broths

Answer 16

aid in the growth of certain bacteria

• MAC- E. COLI
• GN- Shigella/ Salmonella
• Selenite F broth: Shigella
• campythioglycollate broth:campy
• alkaline peptone water- vibrio

Question 17

Supportive BAP

Answer 17

abscence of normal flora

-screen oxidase + colonies, vibrio, aeromonas, piesoomonas

Question 18

Salmonella

Answer 18

Gram negative rods

• transmitted human to human(S. Typhi) or animal to human
• motile
• indole neg does not ferment
• decarboxylated lysone
• H2S+ and variable gas production
• clear colonies on a MAC plate and green colonies on a HEK plate

Question 19

Shigella

Answer 19

Gram Negative rod
- nonmotile***
- indole variable,  does not ferment, lysine negative
- H2S negative***
-  no gas production***
- Five "F"s, only human reservoirs
bacillary dysentary

Question 20

Yersinia

Answer 20

CIN agar bullseye colony

• GNR
• lac negative
• indole negative
• sucrose
• H2S positive