what bacteria causes strep throat

Strep throat is an infection in the throat and tonsils caused by bacteria called group A Streptococcus (group A strep) . This bacteria is also known as Streptococcus pyogenes. Strep A bacteria are very contagious and can be spread through respiratory droplets, direct contact, and rarely, through food that is not handled properly. The bacteria often live in the nose and throat, and people who are infected spread the bacteria by talking, coughing, or sneezing, which creates respiratory droplets that contain the bacteria. People can also get sick if they breathe in respiratory droplets that contain the bacteria or touch something with those droplets on it and then touch their mouth or nose. It usually takes two to five days for someone exposed to group A strep bacteria to become ill with strep throat.