It is possible to get tetanus from a rusty nail, depending on the assessment of the wound.
Tetanus is a specific infection often associated with trauma. The causative agent is Clostridium tetani, which is found in nature, especially in soil. Rusty nails are low in cleanliness and are susceptible to the distribution of Clostridium tetani. It is possible to be infected with Clostridium tetani after being stabbed by a rusty nail, but infection with Clostridium tetani does not necessarily lead to illness.
Because Clostridium tetani is a specialized anaerobic bacteria, can not grow in an aerobic environment, if the wound is deep, and the outer mouth is small, the wound is filled with necrotic tissue, blood clots, or filled too tightly, local ischemia, etc.; or at the same time the existence of itch-demanding bacterial infections, consuming the wound residual oxygen, the formation of a suitable for Clostridium tetani growth and reproduction of the oxygen-deficient environment, so that there is a possibility of developing into tetanus.
If you have been stabbed by a rusty nail, it is recommended to go to the hospital to have the wound assessed by a professional doctor and take standardized treatment to avoid aggravation of the condition and endangerment of life.