Group B streptococcal disease refers to infections caused by the bacterium Streptococcus agalactiae. It is especially important in newborns; screening during pregnancy and appropriate antibiotic use during labor can reduce the risk of early-onset newborn disease.

What is group B streptococcal (GBS) disease?

Group B streptococcus, usually abbreviated as GBS in medicine, is the bacterium Streptococcus agalactiae. This bacterium may live in the intestine or genital area of some healthy adults without causing symptoms; in other words, colonization does not always mean disease. However, it can cause serious infections, especially in newborns, pregnant people, and some higher-risk adults. For that reason, the key question is not simply “is the germ there or not?” but under what conditions infection risk develops and how it can be prevented. ^[1][2][5]

Although GBS disease is most often associated with the newborn period, it is not only a problem for babies. In newborns, it can cause severe conditions such as sepsis, pneumonia, and meningitis. In pregnancy, it is associated with urinary tract infection, infection inside the uterus, or postpartum infection. In older adults or adults with diabetes, liver disease, cancer, or other medical problems, bloodstream infection, skin-soft tissue infection, pneumonia, or bone-joint infection may occur. ^[2][5][6]

Why is it important in pregnancy?

GBS becomes especially important in pregnancy because the bacterium can pass from mother to baby during childbirth. Not every carrier mother passes disease to the baby, but when risk occurs, the consequences can be serious. For that reason, guidelines recommend GBS screening at certain weeks of pregnancy and intravenous antibiotics during labor in risk situations. The aim is not to give antibiotics to everyone throughout pregnancy, but to reduce the risk of early-onset neonatal GBS disease in a targeted way. ^[1][3][4]

A positive screening result does not mean there is definitely an active infection; most often it indicates colonization. Even so, once labor begins or the waters break, appropriate antibiotic use can reduce bacterial transmission to the baby. This approach is especially important in preventing early-onset GBS disease during the newborn’s first week of life. The follow-up plan is individualized, taking into account gestational age, previous pregnancy history, fever, and culture result. ^[1][3][4]

What are the symptoms?

In newborns, symptoms are often nonspecific. Breathing difficulty, poor feeding, irritability, fever or low body temperature, excessive sleepiness, feeding problems, bluish discoloration, and reduced responsiveness may all be signs of serious infection. For that reason, any newborn with a decline in general condition should be taken seriously. Families do not need to make the diagnosis themselves; what matters is seeking medical evaluation without delay. ^[2][5][6]

In pregnant people and adults, symptoms vary according to the site of infection. If the urinary tract is involved, burning during urination or frequent urination may occur; in bloodstream infection, fever, chills, and confusion may be seen; in pneumonia, cough, shortness of breath, and chest pain may occur. In skin-soft tissue or bone-joint involvement, local redness, swelling, tenderness, or restricted movement may appear. In other words, GBS is not a single-symptom disease, but one bacterial cause shared by several different clinical pictures. ^[2][5][6]

Who is at higher risk?

Newborns are the most important risk group, especially during the first week of life. In pregnancy, fever during labor, early rupture of membranes, a history of a previous baby with GBS disease, or a GBS-positive culture in the current pregnancy can increase risk. In adults, advanced age, diabetes, obesity, cancer, liver disease, immune suppression, and some chronic health problems can create a background for GBS infection. ^[2][4][5][6]

An important distinction here is that colonization and invasive infection are not the same thing. Many people carry the bacterium and never become ill. Risk assessment depends not only on the culture result but also on the person’s clinical situation. For that reason, rather than interpreting a test result alone, it is safer to proceed with guidance from an obstetrician, pediatrician, or infectious diseases specialist. ^[1][3][4]

How is it diagnosed, and how is it treated?

Diagnosis varies according to age and clinical picture. During pregnancy, screening may be performed with a vaginal-rectal swab. If infection is suspected, cultures can be taken from blood, urine, or other appropriate samples. In a newborn, suspected sepsis is evaluated together with the clinical picture and laboratory findings. The purpose of diagnosis is not only to detect the bacterium, but also to determine the severity of infection and the system involved. ^[1][2][4]

Antibiotics form the basis of treatment. In newborns or adults with severe infection, intravenous treatment may be needed; in some soft tissue or bone infections, surgery may also come up. Antibiotics given during pregnancy for prophylaxis are different from treatment given for active disease. Which antibiotic is used, when, and for how long depends on the clinical picture; for that reason, starting antibiotics on one’s own is not appropriate. ^[2][3][5]

Prevention and when to see a doctor

At present, there is no routine vaccine in use against GBS; prevention is based on screening at-risk pregnant people and giving antibiotics during labor when needed. This approach is effective in reducing early-onset newborn disease. The practical message for families is this: do not miss prenatal care, do not miss the screening time, and always inform the birth team about any previous GBS history. ^[1][3][4][5]

In a newborn, trouble breathing, inability to feed, marked lethargy, fever, or bluish discoloration requires emergency help. In pregnancy, fever, early rupture of membranes, infection symptoms together with contractions, or one of the risk factors previously mentioned by the doctor also requires prompt evaluation. In adults, high fever, severe shortness of breath, confusion, or signs of a rapidly spreading skin infection should not be delayed either. Group B streptococcal disease is a group of infections in which preventable risks exist and which can be managed more safely when recognized early. ^[2][3][5][6]

Personal medical evaluation is important for symptoms that are prolonged, progressive, or clearly affecting daily life; this content does not replace diagnosis and treatment. ^[1]

3) FAQ

Does a positive GBS result in pregnancy mean the baby will definitely become ill?

No. This usually shows colonization. However, appropriate antibiotics during labor can reduce the risk of early-onset newborn disease. ^[1][3][4]

Is group B streptococcus a sexually transmitted disease?

GBS is not mainly classified that way. It can be present in the genital area, but in pregnancy the main concern is the risk of transmission to the baby during childbirth. ^[1][2][5]

Which signs are emergencies in a newborn?

Shortness of breath, poor feeding, excessive sleepiness, bluish discoloration, fever, or marked lethargy require urgent evaluation. ^[2][5][6]

If colonization is not treated, does it always turn into infection?

No. Many people are carriers and never become ill. The decision for treatment or prophylaxis is made according to clinical risks. ^[1][3][4]

Is GBS seen only in babies?

No. It can also cause serious infections in pregnant people and in older adults or adults with chronic illness. ^[2][5][6]