Sep 22, 2012
Prior to the mid 1960's Group B streptococcal (GBS) infections in humans were almost unheard of.
By the mid 1970's there had been a meteoric increase in the number of infections.
Worst of all, the infections were occurring in pregnant women and their newborns, with case fatality rates
Group B Streptococcus is a type of bacteria which typically colonizes the vagina and lower gastrointestinal tract of women. It is likely that virtually every woman is colonized by GBS at some point in their lifetime. Approximately 20-30% of all pregnant women are current carriers. Colonization (meaning that the bacteria is detectable in the vagina or GI tract) can be transient, it can be intermittent or it can be chronic. Carrier status can change from one pregnancy to the next. Carrier status is different from infection because a carrier has no symptoms.
Whether a mother is a carrier is usually determined by obtaining a swab from the vagina and/or rectum of the pregnant mother.
Infections caused by Group B Strep
In newborns, GBS infections are divided into two groups--early onset and late onset.
Early onset cases occur within the first week of life with most cases diagnosed on the day of birth or within 72 hours.
GBS causes infection in the blood, lungs, brain and spinal fluid, or other milder infections, of the skin for example.
Late onset cases occur after the first week of life. Meningitis (infection of the spinal fluid) is diagnosed in up to one third of late onset cases and permanent neurologic injury can follow.
In mothers, GBS causes urinary tract infections, infection of the placenta and membranes during labor, infection of the uterus after delivery and infection of the blood known as bacteremia.
Group B strep infections can be very successfully treated with antibiotics, especially penicillin or ampicillin.
Prevention of the infection is preferable however, and several strategies have been developed in an attempt to eradicate colonization and infection. The current strategy is to identify colonized mothers and treat them with antibiotics while they are in labor.
In 2002 the CDC, AAP, and ACOG recommended screening (obtaining a recto-vaginal swab from) all expectant
mothers between 35-37 weeks of their pregnancy. Antibiotics are then given to those who were culture positive at the time of the test.
Data from 2003 (one year after the guideline was issued) showed a 34% decline in early-onset disease.
In the future, hospitals may switch to a rapid test for group B strep that can be obtained from the woman when she is in labor. Tests for GBS that give immediate results are in the pipeline and already in use in some institutions.
Rapid tests would be superior to the current strategy because carrier status can change in the interval between 35-37 weeks and delivery.
Another exciting development is a vaccine against GBS, which may soon be used in young teens to immunize them against GBS ( similar to the HPV vaccine, Gardasil).
Continued efforts are being made to protect women and children from the devastating effects of Group B Strep.
There is very real hope that in the future, the disease will be a thing of the past.