Ep 20. Part 2: Group B Streptococcus (GBS) Debrief. What is the evidence for screening all pregnant women?

Part 2: Group B Streptococcus (GBS) What is the evidence for screening all pregnant women with a swab? 

One doctor would get the swab on the private system and another would not

Listen Now.

Dr Lydia Yarlott and Dr Eliz Kilich discuss the two sides of the coin: To get the screening swab for Group B Streptococcus (GBS) or not. The discussion revolves around why different countries have different policies. GBS is a bacteria carries by around 1 in 4 people and can cause sepsis, pneumonia and meningitis in babies when a mother who carries the bacteria (as part of her normal microflora) inadvertently transfers it to baby during delivery of her baby. It is however rare. We follow up on the previous episode with Professor Kirsty Le Doare, an expert in GBS and a leader in running the trials that will hopefully lead to a GBS vaccine for the public in the future. Thus the discussion follows:

1. What are the benefits of the swab as part of screening and if your country of residence does not offer it as routine, would the hosts consider getting it. Spoiler - one would, one wouldn't

2. What are the risk of the bacteria to the baby and what is the actual numerical risk. How many babies need to be delivered to a mum who carries the bacteria for one of the babies to actually get the disease? 

3. Are there any downsides to the antibiotics in labour for GBS given that there will be some people due to screening who get it that may not have needed it? If so is there actual proof? How to we weigh this up against the risk of severe illness to baby? 

4. What was the evidence that led to some of the differing recommendations and why can't we do a study now.

 

 

References:

1. Azad, M. B. et al. Impact of maternal intrapartum antibiotics, method of birth and breastfeeding on gut microbiota during the first year of life: a prospective cohort study. BJOG 123: 983-993. (2015)
2. Corvaglia. et al. Influence of intrapartum antibiotic prophylaxis for Group B Streptococcus on gut microbiota in the first month of life. JPGN 62: 304-308. (2016)
3. Gensollen, et al. How colonization by microbiota in early life shapes the immune system. Science 352(6285): 539-543. (2016)
4. Group B Streptococcus Incidence. Rates of GBS infection in Babies. Group B Strep Support Charity: https://gbss.org.uk/professional-resources/gbs-incidence/ Accessed June 2025
5. Le Doare, K. et al. Intrapartum antibiotic chemoprophylaxis policies for prevention of Group B Streptococcal disease worldwide: Systematic Review. Clin Infect Dis 65(S2): S143-S151. (2017)
6. Matorras et al.  Maternal colonization by group B streptococci and puerperal infection; analysis of intrapartum chemoprophylaxis. Eur J Obstet Gynecol Reprod Biol 38(3): 203-207. (1991)
7. Mazzola et al. Early gut microbiota perturbations following intrapartum antibiotic prophylaxis to prevent group B streptococcal disease. PLoS ONE 11(6): e015727. (2016)
8. Nanduri et al. Epidemiology of invasive early-onset and late-onset group B streptococcal disease in the United States, 2006 to 2015: Multistate laboratory and population-based surveillance. JAMA Pediatr 173(3): 224-233. (2019)
9. Ohlsson, A et al. Intrapartum antibiotics for known maternal group B streptococcal colonization. Cochrane Database Syst Rev 1: CD007467. (2013)
10. Puopolo, K. M. et al. American Academy of Pediatrics, Committee on Fetus and Newborn, Committee on Infectious Diseases et al. Management of infants at risk for Group B Streptococcal disease. Pediatrics 144 (2): e20191881. (2019)
11. Van Dyke, M. K. et al. Evaluation of universal antenatal screening for group B streptococcus. N Engl J Med 360(25): 2626-2636. (2009)