Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
Clostridium tetani is a gram-positive rod-shaped bacterium that is found worldwide in soil; it is usually in its dormant form, spores, and becomes the rod-shaped bacterium when it multiplies. The vegetative rods produce the spore usually at one end of the rod (Figure 1). The organisms are considered anaerobic.
Clostridium tetani is the bacterium responsible for the disease. The bacteria are found in two forms: as a spore (dormant) or as a vegetative cell (active) that can multiply.
The spores are in soil, dust, and animal waste and can survive there for many years. These spores are resistant to extremes of temperature.
Contamination of a wound with tetanus spores is rather common. Tetanus, however, can only occur when the spores germinate and become active bacterial cells.
The active bacterial cells release two exotoxins, tetanolysin and tetanospasmin. The function of tetanolysin is unclear, but tetanospasmin is responsible for the disease.
The disease typically follows an acute injury or trauma that results in a break in the skin. Most cases result from a puncture wound, laceration (cut), or an abrasion (scrape).
Other tetanus-prone injuries include the following: