Real-time PCR-assay in the delivery suite for determination of group B streptococcal colonization in a setting with risk-based antibiotic prophylaxis

Abstract

Objective: Intrapartum antibiotic prophylaxis (IAP) reduces the incidence of neonatal early onset group B streptococcal infections. The present study investigated if an automated PCR-assay, used bedside by the labor ward personnel was manageable and could decrease the use of IAP in a setting with a risk-based IAP strategy.

Methods: The study comprises two phases. Phase 1 was a multicenter, randomized, controlled trial. Women with selected risk-factors were allocated either to PCR-IAP (prophylaxis given if positive or indeterminate) or IAP. A vaginal/rectal swab and superficial swabs from the neonate for conventional culture were also obtained. Phase 2 was non-randomized, assessing an improved version of the assay.

Results: Phase 1 included 112 women in the PCR-IAP group and 117 in the IAP group. Excluding indeterminate results, the assay showed a sensitivity of 89% and a specificity of 90%. In 44 % of the PCR assays the result was indeterminate. The use of IAP was lower in the PCR group (53 versus 92%). Phase 2 included 94 women. The proportion of indeterminate results was reduced (15%). The GBS colonization rate was 31%.

Conclusion: The PCR assay, in the hands of labor ward personnel, can be useful for selection of women to which IAP should be offered.

• Antibiotics
• delivery
• prophylaxis
• real-time PCR
• S. agalactiae

Acknowledgements

During the study Diagen AB (Stockholm, Sweden) provided PCR-instruments and cartridges to all participating units. All other expenditures were funded by the providing units and by a research grant from the Swedish Strategic Program against Antibiotic Resistance (STRAMA).