Infections in Neonates and Young Children

This chapter covers infections in neonates and young children. In this chapter the term ‘young children’ indicates children under two years of age. For information on congenital infections interested readers are referred to Chapter 37. Early neonatal infection is variably defined as infection presenting up to a week after birth, but most infections present in the first seventy-two hours. Microbial invasion of the chorio-amniotic membranes or uterine cavity occur in a significant proportion of pregnancies before rupture of membranes (> 50% with preterm birth before thirty weeks gestation, 10% with term delivery), and in the majority of those with prolonged rupture of membranes (> 24 hours). It is likely that the majority of cases of early sepsis arise through ascending infection of the uterus (through the cervical canal). Ascending infection may be important in the pathogenesis of preterm birth and is more common in infants born preterm. Group B Streptococci (GBS) (Streptococcus agalactiae) and Escherichia coli are the most common agents of early neonatal infection. Infection with Listeria monocytogenes probably arises following ingestion of contaminated food by the mother, blood stream infection, and transplacental spread. Early infection with GBS usually presents with respiratory distress and can be difficult to differentiate from respiratory distress associated with other causes, particularly prematurity. The incidence of GBS blood stream infection in England and Wales has been 0.3–0.45/ 1000 live births over the last five years. Maternal genital herpes simplex infection can spread to the newborn infant and cause a wide range of serious clinical presentations, with skin, systemic, and central nervous system involvement. Maternal infection with Neisseria gonorrhoea or Chlamydia trachomatis can also infect the infant. Either can cause conjunctivitis which can sometimes be of sufficient severity to cause substantial damage to the eyes. Gonococcal conjunctivitis usually presents in the first few days of life. Infection with Chlamydia trachomatis (conjunctivitis or pneumonitis) tends to present later. Traditionally, penicillin and an aminoglycoside have been used to treat infants with suspected early sepsis (to cover GBS and Escherichia coli). Newborn infants are often empirically treated because it can be difficult to differentiate early bacterial sepsis from respiratory distress associated with prematurity, and death may ensue rapidly if the infection is not treated.