Question

One characteristic of Enterobacteriaceae is that they all ferment glucose. Coliforms, on the other hand, are only coliforms if they ferment glucose AND vigorously ferment lactose. Bacteria can be both an Enterobacteriaceae and a Coliform. a. Which media do you look at to tell if the bacteria is able to ferment glucose? b. Which media do you look at to tell if the bacteria is able to ferment lactose?

Answer 1

Different fermentation test for both glucose and lacrosse should be done to find out whether the particular bacteria is present and it's activity is being carried out. For enteric bacteria, glucose fermentation test is done with the help of glucose fermentation broth containing trypticase, sodium chloride and phenol red in a Durham tube. Then glucose is added as the carbohydrate. If fermented broth changes it's colour to yellow then fermentation is occurring.

In case of lacrosse fermentation by colliform, identification can be done by phenol red lactose broth. A change from red to yellow indicated the fermentation process is being carried out.

Kligers iron agar is the method to find out both