Group B Streptococcus Threatens Babies and Seniors

Armen Hareyan's picture


People tend to think of emerging infectious diseases as exotic, affecting people on the other side of the world. Dr. Craig Rubens, professor of pediatrics and microbiology at the University of Washington and chief of the division of pediatric infectious disease, immunology and rheumatology at Seattle's Children's Hospital and Regional Medical Center, says that a bacterial infection is becoming increasingly common in the United States, after starting out as a bacterium that sickened cows.

"Group B streptococcus was reported as causing human disease for the first time in the 1920s," Rubens says. "It wasn't until the '70s that it took off as a major cause of disease in humans."

This isn't the bacteria that cause what's commonly called strep throat, although they are related to that bacteria. Instead, group B strep is one of the most common bacterial infections in newborn babies and young infants under the age of three months.

"It's contracted by being transmitted from the mother's reproductive tract to the baby either during pregnancy or delivery," Rubens says. "When the baby gets infected early on, the bacteria get into the lungs, where the infection causes severe pneumonia. The bacteria can then get into the bloodstream, and go on to infect other organs. Even though we can save many of these babies, thanks to the technology in intensive care units and antibiotics, as many as 30 percent to 50 percent of babies with the early form of the disease will have complications like blindness, cerebral palsy, seizure disorders, learning disabilities, or deafness."


A baby can also contract group B streptococcus after birth, from a family member or another person in the household or community.

Rubens says, "These slightly older babies often do a little better than the newborns, so the incidence of complications is less, but they still get very sick."

Older people also are at risk of contracting group B strep as well, Rubens says. "This bacterium has become a more common cause of serious infection in our elderly and immune-compromised populations. People with diabetes, cancer and other chronic diseases are at high risk for the particular bacteria that causes serious bloodstream infections and complications."

Vaccines to fight group B strep are being developed and tested, but they are still a few years away from being available to the public. In the meantime, since 2002, the Centers for Disease Control and Prevention have recommended that pregnant women be tested for group B streptococcus as part of their prenatal care. Then women who are positive for the bacteria receive antibiotics during labor, to help prevent passing the bacteria to their babies.

"If you're pregnant and you aren't hearing that you are going to be screened for group B strep," Rubens says, "don't be afraid to ask about it. Before antibiotics were available, about 8,000 to 10,000 babies a year were infected with this bacteria."

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