Neonatal sepsis diagnostics: Conventional versus molecular methods – A review

Neonatal sepsis has remained a foremost cause of morbidity and mortality globally, specifically in low- and middle-income countries. The neonatal period, which spans the first 28 days of life, has the highest lifetime risk of sepsis, and when combined with preterm birth, accounts for almost 50% of total deaths worldwide among children aged <5 years. The identification (ID) of the pathogen causing sepsis, as well as its antimicrobial susceptibility testing (AST), is of prime importance to determine the best course of treatment to improve patient outcomes. Although blood culture, the currently accepted gold standard, has the drawbacks of prolonged turnaround time, low sensitivity due to low-volume blood sampling and the confounding effect of prior antibiotic use, as well as a high rate of culture-negative sepsis, newer molecular techniques such as polymerase chain reaction (PCR)-based tests, multiplex PCRs, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and next-generation sequencing have gained attention as promising alternatives or supplements to traditional culture techniques in recent years. This review critically evaluates and compares the performance, advantages, and limitations of conventional and molecular methods for pathogen ID and AST in neonatal sepsis (0–28 days), drawing on recent evidence, and contextualizing findings within current guidelines from the Indian Council of Medical Research, the Centers for Disease Control and Prevention, and the Indian Academy of Pediatrics.