47

Neonatal sepsis occurs with an incidence of 1 to 10 cases per 1,000 live births and has a mortality rate of approximately 10% in industrialized countries. These infections, associated with significant morbidity and mortality, require early detection to prevent delays in treatment. Blood culture remains the gold standard for diagnosing neonatal sepsis. It must be performed using a volume appropriate to the newborn’s weight, with culture bottles designed for pediatrics. The primary challenge is distinguishing contamination from true bacteremia. Cerebrospinal fluid sampling is essential in cases of confirmed bacteremia. The interpretation of results, including cytology and culture, must take the newborn’s age into account. Urine culture and cytology are also recommended in cases of early- or late-onset infections, particularly when risk factors such as urinary catheterization are present. As with adults, the results should be interpreted according to the sample’s origin. Respiratory samples are indicated in newborns with ventilator-associated pneumonia (VAP) or when colonization by Ureaplasma spp. or Mycoplasma spp. is suspected. Additional samples, such as ocular swabs, are collected on a case-by-case basis depending on the clinical signs observed. A major challenge with neonatal sampling is the difficulty of collection and the high risk of contamination. Distinguishing contamination from true infection is often difficult. In recent years, the advent of molecular biology has brought new perspectives to the management of neonatal sepsis, although its limitations must be clearly understood by clinicians.