Group A streptococci, also known as “strep A”, were the first organisms ever identified to be the cause of a disease.
In the mid-1800s, Hungarian physician Ignaz Semmelweis first noted the link between a lack of hygienic practices – such as handwashing – among medical staff and puerperal (or childbirth) fever. Louis Pasteur subsequently demonstrated that it was caused by the microbe we now refer to as strep A.
