Adaptive response of neonatal sepsis-derived Group B Streptococcus to bilirubin

作者：Hansen Richard^*; Gibson Sophie; Alves Eduardo De Paiva; Goddard Mark; MacLaren Andrew; Karcher Anne Marie; Berry Susan; Collie Duguid Elaina S R; El Omar Emad; Munro Mike; Hold Georgina L^*

来源：Scientific Reports, 2018, 8(1): 6470.

DOI：10.1038/s41598-018-24811-3

Hyperbilirubinemia is so common in newborns as to be termed physiological. The most common bacteria involved in early-onset neonatal sepsis are Streptococcus agalactiae, commonly called Group B Streptococcus (GBS). Whilst previous studies show bilirubin has antioxidant properties and is beneficial in endotoxic shock, little thought has been given to whether bilirubin might have antibacterial properties. In this study, we performed a transcriptomic and proteomic assessment of GBS cultured in the presence/absence of bilirubin. Our analysis revealed that increasing levels of bilirubin (>100 mu mol/L) negatively correlated with GBS growth (18% reduction from 0-400 mu mol/L on plate model, p < 0.001; 33% reduction from 0-100 mu mol/L in liquid model, p = 0.02). Transcriptome analysis demonstrated 19 differentially expressed genes, almost exclusively up-regulated in the presence of bilirubin. Proteomic analysis identified 12 differentially expressed proteins, half over-expressed in the presence of bilirubin. Functional analysis using Gene Ontology and KEGG pathways18 revealed a differential expression of genes involved in transport and carbohydrate metabolism, suggesting bilirubin may impact on substrate utilisation. The data improve our understanding of the mechanisms modulating GBS survival in neonatal hyperbilirubinemia and suggest physiological jaundice may have an evolutionary role in protection against early-onset neonatal sepsis.

• 出版日期2018-4-24