What is GBS?
GBS SMEARS – PREVENTION OF PERINATAL INFECTIONS
Anna Kryza, MD: Pregnant women often ask about the 'GBS test’ – why do we do it, 'why don’t I get treatment if the culture is positive’, 'why do we do it only in advanced pregnancy, it’s better to treat the infection as early as possible, isn’t it’? I decided to clear up the doubts about this issue that is bothering so many moms-to-be.
Group B Streptococcus agalactiae (GBS) is a bacterium commonly found in the genital tract, urinary tract, and lower gastrointestinal tract of humans. It is estimated that even 10-30% of women are carriers of this microorganism, without being aware of it, because in most cases we are dealing with colonization (the bacterium is present and multiplies but does not cause any reaction from the body, the so-called colonization – it is not an infection!). Pregnant women are particularly vulnerable to streptococcal outbreaks due to the extremely favourable conditions of the genital tract during this period of a woman’s life.
Despite the fact that streptococcus lives in the body of a pregnant woman, it is not the greatest danger for her, but for her unborn child after birth. This is because during childbirth, the microorganism is transmitted through the mouth to the newborn’s respiratory and digestive systems. This occurs in 70% of GBS-positive women who do not receive adequate prophylaxis during childbirth, as we will discuss later in this article. Early infections (within 7 days of delivery) can take the form of various respiratory illnesses, such as pneumonia, or even systemic infections (sepsis). Late infections – between 7-90 days of life of a child, are of a non-specific nature and may manifest as fever, weakness, respiratory diseases, meningitis. As you can see, the consequences of colonization in a mother can be very serious for her new-born child.
The prevalence of GBS and the serious consequences of GBS infection in the new-born during childbirth have led specialists to develop and implement diagnostic methods and appropriate prophylaxis to minimize the risk associated with the presence of streptococcus B in the genital tract of a pregnant woman. Every pregnant woman should have a smear for streptococcus B between 35-37 weeks of pregnancy, so that a result is obtained before the onset of labour activity. Early smear tests for this organism in pregnant women with normal pregnancy history are not justified due to easy microbial transmission in this group of women and lack of indications to treat colonization with this organism – treatment has no lasting effect and exposes to the effects of the drugs used.
Preventive measures are taken in the delivery room. They involve administering appropriate (baby-safe) antibiotics designed to prevent the transmission of bacteria from mother to new-born. Prophylaxis is indicated not only by positive smears but also by medical history and obstetric situation: initiation of labour before smear results are available (before 35-37hbd), occurrence of infection due to Str. agalactiae B in the new-born after previous deliveries, positive urine culture (presence of streptococcus B) at any stage of the current pregnancy. Patients with a history of allergy to certain antibiotics also do not have to worry because they will be treated with a substitute antibiotic according to PTG recommendations.
The management of the new-born after delivery also depends on the results of the swabs taken during pregnancy and, in the absence of positive results, on the perinatal prophylaxis used. New-borns of GBS-positive mothers, depending on the prophylaxis used, require more intensive neonatal surveillance and sometimes additional diagnostic testing to help with early diagnosis and early treatment if signs of infection occur.