Which of the following is true of tetanus infection?

Which of the following is true of tetanus infection? Choose all correct answers.

Severe cases may result in opisthotonos and death due to spasms of respiratory muscles.

It's symptoms are caused by a neurotoxin produced by the bacteria.

Bacteria spread from the infection site causing inflammation in the affected area of the body.

Antibiotic therapy is the most effective treatment for those showing signs of tetanus.