Clostridium tetani is an obligate anaerobe that can cause tetanus. When it enters the human body, it can produce tetanus toxin. Considering that C. tetani is an obligate anaerobe, which of the following explains how it can survive and cause disease in the human body?

a. Especially in deep wounds, C. tetani can sometimes survive in areas with damaged tissue and poor to no blood flow.

b. C. tetani can only survive when other bacteria are available to consume oxygen and to keep oxygen levels low.

c. It doesn't survive; it simply releases toxin as it dies.

d. C. tetani can't access atmospheric oxygen, so it can grow as long as it stays on the surface of the skin rather than in well-oxygenated deeper tissues.

a. Especially in deep wounds, C. tetani can sometimes survive in areas with damaged tissue and poor to no blood flow.

Explanation:

Clostridium tetani (C. tetani) is an anaerobic soil bacterium; this means that this organism can not live in the presence of oxygen. C. tetani produces tetanospasmin, a toxin that in the human body can interfere with the normal muscle contractions and produce tetanus.

When a human being suffers a deep cut, this bacterium can enter and thrive within the human because, although the tissues of the human body are oxygenated, the cut causes dead tissue (without oxygen), or damaged tissue with poor to no blood flow (and therefore with low oxygen concentrations). Also, the depth of the cut prevents oxygen from entering the outside. These factors give the anaerobic conditions to the bacteria to thrive.