Microsoft Word - NEO175BF

Prof. Alistair G. S. Philip, MD, Division of Neonatal and Development Medicine, Stanford University Medical Center, 750 Welch Road, Suite 135, Palo Alto, CA 94304 (USA) Epidemiology During the past 50 years or so, since the introduction of antibiotics, the predominant organisms causing neonatal sepsis have fluctuated to a considerable extent. In contrast, the characteristics of infants who develop neonatal sepsis have remained relatively constant. It has been documented that low birth weight infants ( < 2,500 g) and particularly very low birth weight infants ( < 1,500 g) are more susceptible to bacterial infection than larger infants; males are more susceptible than females; several risk factors (e.g., prolonged rupture of the membranes) predispose to infection, and that infants admitted to neonatal intensive care units are more likely to demonstrate infection. A wide variety of bacteria may produce infection in the neonate, but in the 1990s there are a handful of organisms that are frequently implicated in neonatal infection [1]. Throughout the neonatal period, Escherichia coli remains a constant threat, with a high case fatality rate. In the first few days after birth, group B streptococcus (Streptococcus agalactiae) is most prominent, although this may be changing with a more aggressive obstetrical approach to women colonized with group B streptococci. Later in the neonatal period, the most common pathogen (not usually considered pathogenic 20 years ago) is coagulase-negative staphylo-coccus [2], usually Staphylococcus epidermi-dis, although Staphylococcus aureus (coagu-lase-positive) is also frequently seen in some centers. The rise in coagulase-negative staphy-lococccal infection is associated with the marked improvement in survival of infants with a birth weight of < 1,000 g. This group is also susceptible to fungal infection, particularly due to Candida albicans. Diagnosis The key to early diagnosis is a high index of suspicion. Because the clinical manifestations of neonatal bacterial infection are so diverse, many neonates are investigated but few are proved to have infection. In addition to time-honored clinical features, such as lethargy, temperature instability and abdominal dis-