Advantages and disadvantages of group B Streptococcus (GBS) carriage identification methods
| Universal screening | Risk-based approach | RDT | |
|---|---|---|---|
| Advantages | Targeted prevention of GBS transmission from mother to baby Can monitor GBS carriage among women over time | Easier to implement—no laboratory set-up required No requirement for mass antenatal screening Cheaper to implement than universal screening or RDTs | Potential to rapidly identify those at highest risk of passing GBS to neonate and can be done intrapartum No requirement for mass antenatal screening Could be employed in preterm deliveries. |
| Disadvantages | Logistical challenges—relies on full laboratory set-up, appropriate transport and storage conditions and timely communication to clinical staff/pregnant women Difficult to collect specimens at correct gestation in areas where antenatal scans are not readily available Results can take 18–48 hours—results may not be available in time GBS colonisation state is dynamic, and GBS status may change from screening to delivery Will miss 7–11% of preterm deliveries, which can account for 32–38% of neonatal GBS EOD | Overlooks the biggest risk of GBS EOD, which is presence of maternal GBS colonisation or GBS bacteriuria Potential to overtreat pregnant women with IAP who do not carry GBS and miss those who may actually have GBS colonisation Will not prevent EOD in settings where there are more home deliveries or in primary healthcare settings with limited diagnostic and treatment facilities No samples collected—difficult to monitor true effect on GBS carriage rate, transmission and any development of antibiotic resistance | Cost issues: running the tests, storing of reagents, training of staff in performing tests and reading results Clinical relevance of molecular assay technique still needs to be quantified |
EOD, early-onset GBS disease; IAP, intrapartum antibiotic prophylaxis; RDT, rapid diagnostic tests.