Early time to positivity in blood cultures as an indicator of mortality in very low birth weight neonates – A retrospective observational cohort study

Abstract

Introduction: Neonatal sepsis is an important cause of mortality. Blood culture is the gold standard for the diagnosis. Time to positivity (TTP) in blood cultures may help in early optimization of treatment in sick neonates. Methods: This was an observational study. Data records were collected for all neonates who were screened for both early- and late-onset sepsis. BacT/Alert system was used for culture detection. For every positive culture, TTP was calculated as the difference between loading time and detection time. Primary outcome was correlation of TTP with mortality due to culture-proven sepsis in gestational age ≤ 34 weeks. Results: 151 VLBW neonates with culture-proven sepsis were included in the study over a period of 22 months. Gram-negative organisms were the predominant isolates, with Klebsiella pneumoniae being the commonest organism. Median TTP was significantly lower in the mortality group (9 hours, IQR 5-24) versus the survivor group (20 hours, IQR 9-78) with a p-value < 0.001. Early-onset sepsis was significantly higher in the mortality group (60%) versus the no-mortality group (27.9%). On multivariate analysis, TTP was the only factor significant in the neonatal mortality amongst the cohort with a p-value < 0.001 and AOR 1.54, 95% CI 1.22-1.93, indicating higher odds of death in neonates with a shorter duration of TTP. Conclusions: TTP is an important predictor of neonatal mortality. Neonates with shorter TTP had higher odds of neonatal mortality due to sepsis. Thus, TTP can be used as a guide for optimal and judicious treatment in neonatal sepsis.

Keywords

• neonatal sepsis
• time to culture positivity
• mortality