Potential Application of Bacteriophages in Enrichment Culture for Improved Prenatal Screening.

Vertical transmission of can cause neonatal infections. A culture test in the late stage of pregnancy is used to screen for the presence of maternal for intrapartum antibiotic prophylaxis. For the test, a vaginal⁻rectal sample is recommended to be enriched, followed by bacterial identification. In some cases, overgrows in the enrichment culture. Consequently, the identification test yields false-negative results. Bacteriophages (phages) can be used as antimicrobial materials. Here, we explored the feasibility of using phages to minimize false-negative results in an experimental setting. Phage mixture was prepared using three phages that specifically infect : phiEF24C, phiEF17H, and phiM1EF22. The mixture inhibited the growth of 86.7% (26/30) of vaginal strains. The simple coculture of and was used as an experimental enrichment model. Phage mixture treatment led to suppression of growth and facilitation of growth. In addition, testing several sets of and strains, the treatment with phage mixture in the enrichment improved detection on chromogenic agar. Our results suggest that the phage mixture can be usefully employed in the culture test to increase test accuracy.