Group Beta Streptococcus (group B strep) is one of the many types of bacteria that live in the body and usually does not cause serious illness. It is typically found in the digestive, urinary, and reproductive systems of both men and women. However, in the United States, group B strep is the leading cause of sepsis (infection in the blood), pneumonia (infection in the lung), and meningitis (infection of the fluid and lining around the brain) in a newborn’s first week of life. About 25 percent of pregnant women carry group B strep in the rectum or vagina. Adults can also have bloodstream infections and pneumonia as well as skin and soft-tissue infections and bone and joint infections.
A person who has the bacteria but no symptoms is considered to be colonized. Most pregnant women who are colonized with group B strep have no symptoms or illness. A small number of women may develop urinary tract infections or infections of the uterus that are caused by group B strep. The most serious effect is that a woman colonized with group B strep late in her pregnancy may pass it to her baby.
There are two types of group B strep infections: early-onset infections and late-onset infections. Early-onset infections occur during the first week of life, typically within the first 24-48 hours after birth. These infections can occur when a baby moves through the birth canal of a woman who is colonized with group B strep. Late-onset infections occur after the first six days of life. These infections may be passed from the mother to the baby during birth or they may be caused by contact with other people who are colonized with group B strep. The symptoms of group B strep can seem like other health problems in newborns and infants. The most common symptoms are: fever, difficulty feeding, irritability, lethargy (limpness or difficulty waking the baby), difficulty breathing, or bluish color to the skin.
Some pregnant women are at higher risk of having a baby with early-onset disease. The factors that increase this risk include: testing positive for group B strep late in pregnancy, detecting group B strep in urine during pregnancy, delivering before 37 weeks, developing a fever during labor, having a long period between water breaking and delivery, and having a previous infant with early-onset disease. Late-onset disease is more common among babies who are born prematurely (before 37 weeks) and babies whose mothers tested positive for group B strep.
There are two ways of preventing newborn early-onset disease. The first is testing all pregnant women for group B strep in the vagina and rectum between 35 and 37 weeks. The test is simple and does not hurt. A sterile swab or “Q-tip” is used to collect the sample from the vagina. The second way is giving antibiotics through the vein during labor for all women who test positive for group B strep. Also, women who tested positive for group B strep in their urine at anytime during the pregnancy, those starting labor before 37 weeks, those with prolonged membrane rupture (water breaking 18 hours or more before delivery), and those with fever during labor should be treated with antibiotics.
Penicillin is the most common antibiotic that is given. For women who are severely allergic to penicillin, other antibiotics can be used. Antibiotics are only effective if given during labor, not before, because the bacteria can grow back quickly. Unfortunately, the rates of late-onset disease of group B strep have remained fairly stable since 1990, and a strategy to prevent these infections has not yet been identified. Birth canal washes with a disinfectant chlorhexidine and antibiotics taken by mouth or before labor are not effective in reducing the transmission of group B strep from mother to baby.
Group B strep disease is diagnosed in newborns when the bacteria are grown from samples of the baby’s sterile body fluids such as blood and spinal fluid. Cultures can take a few days to grow. Typically for a mother who that tested positive for group B strep and received antibiotics during labor, the baby will be observed to see if he starts developing symptoms of early-onset group B strep. The doctor will give the newborn antibiotics through the vein in order to treat early or late-onset of group B strep. Additional procedures may also need to be done based on baby’s symptoms.
Group B strep typically doesn’t affect the length of time you and your baby spend in the hospital, and it doesn’t affect your ability to breast-feed safely. A vaccine for group B strep is not available yet, but researches are working on one that could, in the future, help prevent group B strep infections among adults. If you are pregnant, talk to your doctor about group B strep and getting tested between 35-37 weeks or sooner if you develop premature labor.
Melissa Waddell, WHNP, a Hampton Roads native, is a nurse practitioner at Atlantic Ob/Gyn. Please call 757-463-1234 or visit www.atlanticobgyn.com.