Lecture 4

Question 1

MacConkey Agar

Answer 1

A differential medium for the isolation
of coliforms and intestinal pathogens in
water, dairy products, and biological
specimens.

Question 2

Coliforms

Question 3

Use of MacConkey Agar

Answer 3

1. Coliform Differentiation
2. Bacterial Counts

Question 4

MacConkey Agar no.2

Answer 4

A modification of the original formula
containing a different mixture of bile
salts for the recognition of enterococci

Question 5

Use of MacConkey Agar no.2

Answer 5

Mainly used for specimens of water, sewage or food products

Question 6

MacConkey Agar no.3

Answer 6

A selective medium giving excellent
differentiation between coliforms and
non-lactose fermenters with the
inhibition of Gram-positive micrococci

Question 7

Uses of MacConkey Agar no.3

Answer 7

• To isolate salmonella and shigella species from food.
• For the isolation of E.coli in children.

Question 8

Sorbitol MacConkey Agar

Answer 8

A selective and differential medium for
the detection of E.coli O157.

Question 9

Cefixime-Tellurite

Answer 9

• Used for the selective isolation of E.coli
  O157:H7

Question 10

CLED

Answer 10

Cystine-Lactose Electrolyte Deficient
Recommended for diagnostic urine
bacteriology.

Question 11

Uses of CLED

Answer 11

1. Supports growth of all urinary potential pathogens.
2. Gives good colonial differentiation and
   diagnostic criteria.
3. Contains Andrade indicator to enhance
   the differentiation of colony
   characteristics.

Question 12

DCLS

Answer 12

A modified medium containing sucrose to improve the accuracy of recognition of pathogenic Enterobacterales.

Question 13

OF Basal Medium

Answer 13

1. Used for the determination of oxidative
   and fermentative metabolism of
   carbohydrates by Gram-negative rods.
2. Used as a means of differentiating
   species.