Time to positive blood culture in early onset neonatal sepsis: A retrospective clinical study and review of the literature.

Abstract

Neonatal early onset sepsis (EOS) is a low-incidence, high-risk disease which has prompted significant overtreatment with antibiotics for the standard duration of 48 h. The aims of this study were to determine whether blood cultures collected from term and late preterm neonates for EOS would return a positive result for pathogenic bacteria within 24 h and to review the literature to supplement the results. This is a retrospective observational study of time to positive blood culture in the BACTEC culture system from neonates ≥34 weeks in a single referral centre between 1999 and 2018. A literature review was conducted through PubMed, MEDLINE and Embase using search terms of 'neonatal sepsis' AND 'blood culture'. Studies were included if they reported time to positive blood culture in EOS. Forty positive cultures were included in this report, with 39 (98%) showing bacterial growth within 24 h. One culture, obtained after commencement of antibiotics, became positive at 3 days. Sixteen papers were included in our literature review and six presented data for an EOS cohort; a median of 96.5% of pathogenic EOS blood cultures become positive within 24 h. All pathogenic blood cultures collected pre-therapy from neonates ≥34 weeks suspected of EOS returned a positive result within 24 h of incubation. Similar studies have found that 92-100% of cultures are positive by 24 h. This data could contribute to re-evaluation of the current standard duration of antibiotic use in term and late preterm neonates with suspected EOS.