Clostridium tetani

Clostridium tetani is a common soil bacterium and the causative agent of tetanus. Vegetative cells of Clostridium tetani are usually rod-shaped and up to 2.5 μm long, but they become enlarged and tennis racket- or drumstick-shaped when forming spores. C. tetani spores are extremely hardy and can be found globally in soil or in the gastrointestinal tract of animals. If inoculated into a wound, C. tetani can grow and produce a potent toxin, tetanospasmin, which interferes with motor neurons, causing tetanus. The toxin's action can be prevented with tetanus toxoid vaccines, which are often administered to children worldwide. Clostridium tetani is a rod-shaped, Gram-positive bacterium, typically up to 0.5 μm wide and 2.5 μm long. It is motile by way of various flagella that surround its body. C. tetani cannot grow in the presence of oxygen. It grows best at temperatures ranging from 33 to 37°C. Upon exposure to various conditions, C. tetani can shed its flagella and form a spore. Each cell can form a single spore, generally at one end of the cell, giving the cell a distinctive drumstick shape. C. tetani spores are extremely hardy and are resistant to heat, various antiseptics, and boiling for several minutes. The spores are long-lived and are distributed worldwide in soils as well as in the intestines of various livestock and companion animals. Clostridium tetani is classified within the genus Clostridium, a broad group of over 150 species of Gram-positive bacteria. C. tetani falls within a cluster of nearly 100 species that are more closely related to each other than they are to any other genus. This cluster includes other pathogenic Clostridium species such as C. botulinum and C. perfringens. The closest relative to C. tetani is C. cochlearium. Other Clostridium species can be divided into a number of genetically related groups, many of which are more closely related to members of other genera than they are to C. tetani. Examples of this include the human pathogen C. difficile, which is more closely related to members of genus Peptostreptococcus than to C.