There are several types of streptococcal bacteria. Group A streptococci are normally found in the throat and on the skin. GAS bacteria can cause strep throat and impetigo. In more rare cases, GAS bacteria can cause necrotizing fasciitis also known as the flesh-eating bacteria.
Streptococcal bacteria spread through direct contact with mucus from people who have GAS infections or through contact with an infected wound or skin sore. It is also possible to contract an illness by using the same plates or glassware as an infected person. These types of illness are usually mild, and doctors frequently prescribe antibiotics to treat them. Some people carry GAS bacteria and are asymptomatic. These people are much less contagious than those who are actively ill.
GAS bacteria can invade the blood, lungs, fat and deep muscle tissue. When this happens, a life-threatening infection may develop. Necrotizing fasciitis affects the muscle and fat tissue. Streptococcal toxic shock syndrome can cause damage to the lungs, liver and kidneys. About 20 percent of those who contract necrotizing fasciitis die, while about 60 percent of those with streptococcal toxic shock syndrome do not survive.