Flesh eating bacteria Necrotizing fasciitis is a rare infection but can be fatal if not treated properly.It's a kind of bacterial infection that spreads quickly, and can cause tissue death at the infection site and beyond. People can get this disease after being infected by the group A Streptococcus (GAS) bacteria.It's the same bacteria that causes strep throat. It can enter the body through insect bites, minor surgery, minor cuts and abrasions. Once the body is infected, the infection agressively destroys muscle, skin and adipose tissue