The different transmission of group B streptococcus infections in neonates

Abstract

Objective To study the transmission of group B Streptococcus (GBS) in the neonatal infections and the value of randomly amplified polymorphic DNA (RAPD) analysis in the GBS epidemiology. Methods The serotyping, hybridization and RAPD typing methods were used. Seven strains of GBS were detected in 2 pairs of mother-baby, which included 2 strains from the 2 mothers and 5 strains from their babies with early and late-onset infections. Eighty-eight strains of GBS were detected in vaginas of pregnant womens. Results In the two cases, the strains from the paired mother and baby showed the identical serotype (III/R) and restriction fragment length of virulent factor genes that is, alpha and beta genes negative, ScaA 2kb, glnA 6.5kb and ScpB 2.6kb. In the case with early-onset infection, the strains from the paired mother and baby were revealed with the identical RAPD pattern (RAPD1) . In the case with late-onset infection, the strains from the paired mother and baby were revealed with different RAPD patterns, GBS strain isolated from mother was RAPD27, GBS strains from blood and CSF of the baby were RAPD1. Conclusion There may be a vertical transmission between mother and baby in early-onset of GBS infection and cross transmission in late-onset. RAPD analysis provides a valuable molecular tool for studying GBS epidemiology. Key words: Infant, newbron; Streptococcus agalactide; Streptococcal infections; Serotyping; Nucleic acid hybridization; Nucleotide mapping