Real-world use of Serial Clinical Observation in culture-proven early-onset sepsis: timing of recognition, treatment and retrospective comparison with the Neonatal Sepsis Calculator

To assess the real-world performance of the Serial Clinical Observation (SCO) strategy in identifying and treating Early-Onset Sepsis (EOS) cases, and to compare it with the recommendations the Neonatal Sepsis Calculator (NSC) would have provided. This multicentre study analyzed prospectively culture-confirmed EOS cases caused by Group B Streptococcus (GBS) or Escherichia coli (2016-2022) in term and late-preterm infants managed with the SCO approach in Italy. We evaluated the proportion of infants assigned to routine care at birth and the time to antibiotics. NSC scores at 4, 12, and 24 h after birth were retrospectively calculated. Of 57 EOS cases, 23 (40.4%) had no maternal risk factors. Fifty infants developed clinical signs of illness either at birth (n = 24) or postnatally (n = 26). Among those symptomatic at birth, the median time to antibiotic initiation was 2.0 h (IQR 1.0-5.75). "Major" clinical signs according to the SCO protocol were present in 79.2%, prompting immediate antibiotics. Retrospective NSC application at 4 h would have recommended antibiotics in 87.5%. Of the 26 who became symptomatic after birth, 16 (61.5%) were assigned to routine care. The median time from disease onset to treatment was 6.0 h (IQR 2.0-14.0). At 4 h, NSC would have assigned 19 (73.1%) of these infants to routine care. Subtle neurological signs (i.e. hypotonia, irritability, altered consciousness) were frequently observed at onset in infants who developed severe disease.Conclusion: Most EOS cases were appropriately identified among infants with clinical signs at birth, but not among those initially well-appearing. Close clinical observation throughout the first 48 h of life, along with careful attention to "major" signs-including subtle neurological signs-may improve EOS management. What is Known:center dot The Serial Clinical Observation (SCO) strategy reduces unnecessary antibiotic use and laboratory testing in infants at risk of Early-Onset Sepsis (EOS).center dot However, its performance in identifying confirmed EOS cases has never been established nor compared with that of the Neonatal Sepsis Calculator (NSC).What is New:center dot Among neonates clinically ill at birth, SCO and NSC recommended immediate antibiotics in a similar proportion (79% vs 88%).center dot Among infants with EOS who were initially well-appearing, most were assigned to routine care under the SCO approach (62%) or would have been assigned to routine care under the NSC approach (73%).center dot To ensure timely recognition of EOS, universal observation of all infants over the first 24-48 h after birth may be beneficial.