Strep is short for Streptococcus, a type of bacteria. There are several types. Two of them cause most of the strep infections in people: group A and group B.
Group A strep causes
Group B strep can cause blood infections, pneumonia and meningitis in newborns. A screening test during pregnancy can tell if you have it. If you do, I.V. antibiotics during labor can save your baby's life. Adults can also get group B strep infections, especially if they are elderly or already have health problems. Strep B can cause urinary tract infections, blood infections, skin infections and pneumonia in adults.
Antibiotics are used to treat strep infections.
NIH: National Institute of Allergy and Infectious Diseases