Most adults carry group B strep in their bodies and experience no symptoms. When symptoms are present in adults, group B strep can cause urinary tract infections, blood infections and pneumonia, according to Mayo Clinic.
Group B strep commonly lives in the gastrointestinal tracts of adults. Usually, there are no symptoms of a group B strep infection unless the bacteria is causing other issues. If a doctor suspects a group B strep infection, lab tests can identify whether group B strep is present in an adult's blood or spinal fluid. In very rare cases, group B strep causes meningitis in adults, reports the Centers for Disease Control and Prevention.
Pregnant women are tested for group B strep because it is transmittable to babies during labor. Group B strep can cause breathing problems, sepsis, pneumonia and other serious illnesses in newborns, notes the American Pregnancy Association.