GBS stands for Group B Streptococcus, a type of bacteria that can cause infections in newborns, pregnant women, the elderly, and individuals with weakened immune systems. It is commonly found in the gastrointestinal and genital tracts of healthy adults without causing any symptoms. However, it can be passed from mother to baby during childbirth, leading to serious complications such as sepsis, pneumonia, and meningitis in newborns. Screening and treatment during pregnancy can help prevent transmission of GBS to the baby.