Time to positivity of Coagulase Negative Staphylococcus In Neonatal Blood Cultures as an adjunct tool to help discriminate between sepsis and contamination.

Objective: To assess the usefulness of time to positivity (TTP) to distinguish between sepsis and contamination in coagulase-negative staphylococci (CoNS) isolates.

Study Design: Unicentric retrospective observational. Medical records of 168 patients with suspected sepsis and positive blood culture for CoNS were reviewed. Patients were subdivided into sepsis (29%) and probable contamination (71%). Logistic regression analyses were performed to evaluate different risk factors and clinical signs and symptoms associated with sepsis.

Results: TTP cut-off value that best discriminated sepsis from contamination was found to be 18 h. Regression analysis revealed that TTP ≤ 18 h, gestational age ≤32 weeks, taquycardia/bradycardia and hypoactivity/lethargy were independent predictors of sepsis.

Conclusion: TTP is useful in distinguishing sepsis from contamination, especially in neonates with lower gestational age (<32 weeks). The clinical signs that most increase the discriminatory power of TTP are the presence of tachycardia/bradycardia or hypoactivity.