All of the following statements about Necrotizing fasciitis are true, EXCEPT:

Necrotizing fasciitis is a necrotizing infection of the skin and subcutaneous tissue. It is often polymicrobial in origin, Group A Streptococci is the most common causative organism. This infection tends to occur first on an extremity in an otherwise healthy host who had a history of trauma or has had a recent operative procedure at the site of the infection. The most common site of necrotizing fasciitis is the extremities followed by trunk and perineum. Ref: Emergency Medicine: A Comprehensive Study Guide By Judith E. Tintinall, 7th Edition, Chapter 147