The microbiome, metabolome, and proteome in preterm neonatal sepsis

Neonatal sepsis is a major cause of morbidity and mortality worldwide, especially when an infant is delivered preterm. Traditional microbiology has played a pivotal role in identifying the key pathogens associated with neonatal sepsis. However, the aetiology of these infections is not always clear and an organism that initiates disease in one infant may not in another. Utilizing next-generation sequencing technologies, researchers have been able to further characterize the microbiome in neonatal sepsis, offering novel insights into the mechanisms of disease. Biomarkers that have a high sensitivity and specificity for neonatal sepsis have remained elusive, despite an exhaustive effort. High throughput metabolomic screening of samples using cutting-edge technologies such as nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry is a new frontier in the search for diagnostic markers for neonatal sepsis. In this chapter we will review recent advances in the understanding of the role that the microbiome plays in neonatal sepsis. Furthermore, we will discuss how investigation of the proteome and metabolome of biofluids has offered promising new diagnostics for neonatal sepsis.