Group B Streptococcus in 2025: Why Prevention Strategies Must Evolve

In maternity wards, decisions are rarely made in ideal conditions. Labour moves quickly, information can be incomplete, and clinicians are often working against the clock. Group B Streptococcus, or GBS, has long been part of this environment, screened for, managed through protocols, and largely considered under control. Yet the picture emerging in 2025 suggests something more complicated. GBS has not disappeared. Instead, it is changing, and the strategies designed to contain it are starting to show their limits.

This evolving situation means strategies must be reassessed. Evidence drawn from surveillance data, molecular research, and clinical practice points to a moment of reassessment. Work led by Asmaa Tazi and colleagues at the French National Reference Centre for Streptococci highlights a growing gap between what current prevention approaches do well and what they fail to address. Reducing early‑onset disease was a major achievement. But it is no longer enough.

A familiar pathogen, a shifting burden

GBS remains the leading cause of invasive bacterial infection in newborns worldwide. Around one in four pregnant women may carry the bacterium, usually without any symptoms. In most cases, exposure during birth does not lead to illness. But when infection does occur, the consequences can be severe.

Clinically, GBS falls into two distinct categories. Early‑onset disease appears in the first days of life, most often within 48 hours of birth, and is closely linked to transmission during delivery. Late‑onset disease develops later, from the second week up to three months of age and carries a far higher risk of meningitis and long‑term neurological damage¹.

This is where prevention efforts encounter new obstacles. Prevention efforts over the past decades have successfully reduced early‑onset disease in many countries. That progress, however, has masked a less reassuring trend. Late‑onset disease has not declined in parallel. In several settings, it has increased. This divergence exposes a basic limitation of current practice: antibiotics given during labour can protect a newborn at birth, but they offer no protection in the weeks that follow¹.

Where prevention falls short

Most national strategies rely on intrapartum antibiotic prophylaxis, delivered either through universal screening late in pregnancy or through identification of clinical risk factors at delivery. Universal screening has clear benefits. When maternal colonisation is identified and antibiotics are administered during labour, the risk of early‑onset infection drops sharply¹.

In real life, the system is less precise. GBS colonisation is not static. A woman who tests positive weeks before delivery may no longer carry the bacterium at birth, leading to unnecessary antibiotic exposure. Others test negative antenatally but become colonised closer to delivery, missing prophylaxis altogether. Preterm labour, missing test results, or lack of screening only widen these gaps.

In addition to logistical limitations, broader concerns are emerging. Widespread antibiotic use has consequences, from antimicrobial resistance to disruption of the neonatal microbiome. These observations underscore the limitations of antibiotic‑centred prevention and the need to consider additional preventive strategies¹..

What molecular epidemiology is revealing

Molecular data have added clarity to why late‑onset disease remains so difficult to prevent. A hypervirulent clonal complex, known as CC‑17, has emerged as a dominant driver of severe neonatal infections, particularly meningitis and late‑onset disease. Over the past decades, the expansion of CC‑17 has closely tracked the rise in late‑onset cases across multiple countries.

At the same time, susceptibility patterns are slowly shifting. Beta‑lactam antibiotics remain effective in most cases, but strains with reduced susceptibility linked to mutations in penicillin‑binding proteins have been identified. Resistance to clindamycin, often used in patients with beta‑lactam allergy, is already common. These developments reinforce the need for ongoing surveillance and caution against relying too heavily on a single preventive tool.

Precision at the point of care

These findings suggest a move toward more targeted, real‑time approaches at the point of care. In this context, intrapartum molecular screening is gaining attention as a more targeted approach. Real‑time molecular tests performed during labour can identify maternal GBS colonisation within one to two hours, aligning diagnosis with the moment when intervention matters most.

This approach is particularly relevant in preterm deliveries, where antenatal screening is often unavailable or outdated. By relying on real‑time status rather than historical results, intrapartum screening may help avoid mismatches between colonization status and prophylaxis. It is not without limitations; invalid results, cost, and lack of resistance detection remain challenges, but it represents a shift toward greater precision at the point of care.

Beyond antibiotics alone

Perhaps the clearest message emerging in 2025 is that antibiotics alone will not close the prevention gap. Rising late‑onset disease, expanding hypervirulent strains, and evolving resistance patterns demand new solutions. Maternal vaccination stands out as a most promising long‑term strategy. By inducing protective antibodies during pregnancy, vaccination could provide passive immunity to newborns throughout the first months of life, covering both early‑ and late‑onset disease. Several vaccine candidates are now in development, alongside other approaches such as immune‑based therapies and microbiome‑focused interventions¹.

A moment for recalibration

GBS prevention must now move urgently into a new phase. Past strategies have saved lives, but today’s changing landscape demands immediate action: adopt smarter screening, limit antibiotic use to necessity, intensify surveillance, and prioritize the development of strategies, such as maternal vaccination, that protect infants well beyond birth. Health systems must not delay this recalibration.

In 2025, health systems face a choice. Continue to rely on approaches that address only part of the problem or adapt prevention strategies to reflect the evolving nature of GBS. The direction taken will shape outcomes not just in the first hours after birth, but throughout the fragile months that follow.