Early-onset neonatal sepsis (EOS) is difficult to diagnose clinically because the semiology of premature newborns is poor during the first days of life. This study aimed to identify predictive factors of EOS in neonates less than 37 weeks’ gestational age in neonatal care at Louis Mourier Hospital, France.

This was a case–control study of all newborns less than 37 weeks of gestational age diagnosed and managed for EOS from January 1 to December 31, 2019. The main parameters studied were demographic characteristics, risk factors, laboratory, and bacteriological characteristics. At the benchmarking level, the statistical tests used were the McNemar test for qualitative variables and the paired Student's t-test for quantitative variables.

A total of 50 mother–child pairs were included in this study (25 cases and 25 matched controls). The results showed a statistically significant relationship between the birth of a child with EOS and between a premature rupture of membranes of > 18 h (68% of cases vs. 36% of controls; p = 0.042); a positive culture of the placenta (p = 0.0002); C-reactive protein levels of > 6 mg/L (88% of cases vs. 20% of controls; p = 0.001); a procalcitonin level of > 0.6 ng/mL (72% of cases vs. 16% of controls; p = 0.001). Gram-negative bacteria including Escherichia coli (44.5%) and Haemophilus influenzae (14.8%) were the most common pathogens found.

The search for risk factors must be systematic and the clinic must remain at the center of the diagnostic approach.