Streptococcus bacteria are commonly found in the throat and on the skin of people. They can be present in the body without causing any illness, or they can infect different parts of the body and cause mild to severe diseases such as strep throat, impetigo, necrotizing fasciitis, and streptococcal toxic shock syndrome.
The bacteria are spread by direct contact with discharges from the nose and throat of infected people, contact with infected wounds or sores on the skin, or respiratory droplets such as from coughing, sneezing, or talking.
The risk of spreading the infection is highest when a person is ill, such as when people have “strep throat” or an infected wound. People who carry the bacteria but have no symptoms are much less able to spread the bacteria.
Pregnant women can pass the bacteria to their babies during delivery. Treatment of an infected person with an appropriate antibiotic for 12 hours or longer removes their ability to spread the bacteria.