Question

Which of the following media is/are used in the series of tests for the most probable number (MPN) technique?

Select one or more:

a. Lauryl sulfate lactose broth

b. Brilliant green lactose bile broth

c. phenyl ethyl alcohol agar

d. trypticase soy agar

Which of the following media is/are used in the series of tests for the most probable number (MPN) technique?

Select one or more:

a. Lauryl sulfate lactose broth

b. Brilliant green lactose bile broth

c. phenyl ethyl alcohol agar

d. trypticase soy agar

Which of the following statements is correct?

Select one:

a. In the IMViC series: I=Indole, M=Methanol, Vi=Voges-Proskauer and C=Carbon Dioxide

b. The enzyme tryptophanase breaks down the monosaccharide tryptophan to indole, pyruvic acid and ammonia

c. The IMViC series can be useful in distinguishing Salmonella enterica from Enterobacter aerogenes

d. In the IMViC series, Escherichia coli is negative for the Indole test and positive for the Voges-Proskauer test

Answer 1

1. Answer : (a) and (b)

Explanation:

Lauryl sulfate lactose broth is used for MPN technique to calculate the amount of coliforms in the water. This media is used to grow only coliforms by the process of fermentation of lactose and it produces gas. After selecting the gas producing microbes it will be allowed to grow in the 'brilliant green lactose bile broth'. This tests for the growth of organism in the presence of bile. These both media will be used in the MPN technique.

Phenyl ethyl alcohol agar is a selective media for culturing the gram positive microbes and trypticase soy agar is non selective media which allows all type of microbes to grow. It is not used in MPN technique which is used for water quality testing by enumerating the coliforms present in the water.

So the correct option is a and b.