Mannitol salt agar is a type of specialized media that contains enough salts to allow only halophilic (salt-loving) bacteria to grow. In this manner, it is considered to be a selective media. It also contains a pH indicator to test for mannitol fermentation. If the growth turns the media yellow, it is most likely Staphylococcus aureus. If the growth remains pink, it is most likely Staphylococcus epidermidis. In this manner (color indicator), it is considered to be a differential media.
Clostridium tetani is an obligate anaerobic bacterium. This means that:
Clostridium tetani will thrive in large skin wounds that result in significant blood loss.
Clostridium tetani can be transmitted from a dog bite and thrive in a deep wound with minimal loss of blood.
Clostridium tetani prefers to grow in the respiratory tract in a high oxygen environment.
Clostridium tetani requires superoxide dismutase for growth.