Clostridium tetani causes tetanus. According to the Centers for Disease Control and Prevention, one out of every 10 cases of tetanus results in death. Commonly referred to as "lockjaw," this disease can be prevented. The CDC Advisory Committee on Immunization Practices recommends that all infants and children should be vaccinated. Adults should receive a tetanus shot or booster shot.
Definition
Clostridium tetani is a gram-positive rod bacterium. Microbiologists use a staining process, called a gram stain, as one way to classify bacteria. It is called gram-positive because it holds onto the first stain that is used in the staining process. The bacterium is referred to as a rod because it has a rod shape.
Transmission
C. tetani produces spores, which are commonly found in the soil. The spores enter the body through a wound. Drug addicts can get spores in their body if they inject drugs with a technique they call "skin popping," as explained by Warren Levinson, M.D., in Review of Medical Microbiology and Immunology. The spores will then germinate, especially if there is not a good blood supply in the area of the wound.
Disease
While the bacteria are still in the wound, they makes a toxin called tetanospasmin. The toxin sticks to the motor nerves and goes to the central nervous system, the part of the nervous system that is made up of the brain and spinal cord. There it blocks substances, called glycine and GABA, which the nerves use to inhibit or calm down. George Brooks, M.D., writes in "Jawetz, Melnick, & Adelberg's Medical Microbiology" that very small amounts of this toxin are deadly.
Symptoms
According to Dr. Brooks, people may not have any symptoms of tetanus for four days to five weeks. This period of time is referred to as the incubation period. And because the toxin blocks the substances that inhibit the nerves, there is nothing to stop them from being too excitable. This leads to muscle spasms and contractions. At first, the spasms will be in the same area as the wound. But then, spasms will occur in the muscles of the jaw; this is called lockjaw. The muscles can contract so much that people with lockjaw cannot even open their mouths. Eventually other muscles in the body become involved in the disease process. People develop opisthotonus, or spasms so intense that the spine arches inward. Finally the respiratory muscles spasm, and this leads to respiratory failure, the usual cause of death.
References
- Centers for Disease Control and Prevention: Tetanus Disease In-Short (Lockjaw)
- "Jawetz, Melnick, & Adelberg's Medical Microbiology"; George Brooks, M.D., Karen Carroll, M.D., Janet Butel, Ph.D., Stephen Morse, Ph.D.; 2007
- "Review of Medical Microbiology and Immunology," Warren Levinson, M.D., Ph.D.; 2008
