Time to positive blood cultures in neonatal sepsis evaluations

This study evaluates the time to blood culture positivity among neonates evaluated for sepsis to determine when antibiotics may be safely discontinued.

Retrospective review of clinically relevant blood culture time to positivity from infants in a neonatal intensive care unit. The primary endpoint was overall median time to blood culture positivity. Secondary endpoints compared time to positivity among gram-positive versus gram-negative organisms, early versus late onset sepsis, and a sub-analysis excluding contaminants.

Among 151 cultures, the overall median time to positivity was 17 h (IQR 12-23). Most (47/48, 97.9%) gram-negative organisms resulted within 24 h and most (88/94, 93.6%) gram-positive by 36 h. All (13/13, 100%) early onset cultures resulted within 24 h and most (132/138, 95.7%) late onset by 36 h.

Antibiotics for neonatal sepsis evaluation may be safely discontinued in well-appearing infants without an identified infection source with negative cultures at 36 h.