A 40-year old gentleman arrives in the emergency room with a headache, irritability, generalized muscle pain, and uncontrollable back spasms

A 40-year old gentleman arrives in the emergency room with a headache, irritability, generalized muscle pain, and uncontrollable back spasms. He has become very restless and worried because he has had the back spasms all day while at work and they have become extremely painful.     In his history, the man states that he runs his own business and is very busy with work. He injured himself about 10 days earlier, puncturing his left arm with a nail from an old barn he is renovating. The wound has produced moderate quantities of pus, but he has been keeping it clean. When asked, he did not remember having a tetanus shot since he was a kid.     The wound was sampled for microscopic examination and cultured. His back appears to have very tight contractions and spasms. The patient is in obvious agonizing pain.   

  1) What is your diagnosis here?  

2) How could this have been prevented?