Description and Significance. Clostridium tetani is a rod-shaped, anaerobic, and endospore-forming bacterium that is responsible for the tetanus disease, a condition of the central nervous system affecting an estimated 350,000 people a year, worldwide.lostridium tetani is a rod-shaped, obligate anaerobe that is saprophytic in nature. The bacterium forms a terminal endospore through sporulation when survival becomes difficult, usually in the presence of oxygen.