Question

An inoculated thioglycolate medium culture tube is clear throughout the tube except for dense growth at the bottom of the tube. What is your conclusion?

a) The bacterium is an obligate aerobe.
b) The bacterium is an obligate anaerobe.
c) The bacterium is a facultative anaerobe.
d) The bacterium is a microaerophile.

Answer 1

The dense growth at the bottom of the thioglycolate medium culture tube indicates the bacterium is an obligate anaerobe, which cannot tolerate oxygen and only grows in its absence.

Step-by-step explanation:

An inoculated thioglycolate medium culture tube that is clear throughout except for dense growth at the bottom indicates the bacterium in question prefers an environment devoid of oxygen. The correct conclusion is that the bacterium is an obligate anaerobe. Obligate anaerobes are microbes that are killed by the presence of oxygen and hence only grow in its absence, such as at the bottom of a thioglycolate medium culture tube where oxygen diffusion is limited.