Background and aims Procalcitonin (PCT) is used in the early diagnosis of infections. Recently, PCT has been used in both adults and children as a guide to the duration of antibiotic treatment. The aims are to study the evolution of PCT during secondary sepsis in the newborn and to evaluate its ability to guide the duration of antibiotic treatment.

Patients and methods A prospective, observational study including all neonates hospitalised in a level II neonatal unit between December 2011 and January 2013 with suspected infection after 5 days of life and serum PCT >0.6 ng/L. Serial PCT, CRP and blood culture survey was performed according to the usual protocol. Adapted antibiotherapy was administered for 10 days after the last positive blood culture.

Results 54 infective episodes were observed in 46 neonates, born at a mean term of 32 weeks (range: 26–40) and infected for a mean of 19 days (7–40). Staphylococci and gram-negative bacteria caused respectively 57% and 22% of infective episodes. At the time of clinical diagnosis (D0), 74% of the PCT values and 81.5% of the CRP values were positive. Between D5 and D8,80% of PCT measurements were negative (<0.6 ng/L) versus only 25% of CRP. On D8, 47.0% of CRP measurements were still positive. Had antibiotherapy been discontinued when PCT was <0.6 ng/ml, it would have been 5 days shorter.

Conclusion In newborn with secondary sepsis, serum PCT may help to reduce antibiotherapy duration and this should be examined in a controlled study.