ABSTRACT
The incidence of infection in the fetus and newborn infant is high. As many as 2% of fetuses are
infected in utero and up to 10% of infants are infected during delivery or in the first fewmonths
of life. The predominant microorganisms known to cause these infections are cytomegalovirus,
herpes simplex virus, rubella virus, Toxoplasma gondii, Treponema pallidum, Chlamydia, Group B
Streptococcus, Enterococcus spp., Escherichia coli, and anaerobic bacteria. All of these agents can
colonize or infect the mother and infect the fetus or newborn either intrauterinely or during the
passage through the birth canal. Although anaerobic bacteria cause a small number of these
infections, the conditions predisposing to anaerobic infections in newborns are similar to those
associated with aerobic microorganisms. Furthermore, the true incidence of anaerobic infec-
tions may be underestimated because techniques for the recovery and isolation of anaerobic
bacteria are rarely used, or are inadequate. Several factors have been associated with
acquisition of local or systemic infection in the newborn. Most of these factors are vague and
difficult to define; however, most studies have described the presence of one or more risk
factors in the pregnancy and delivery of these infants: premature and prolonged rupture of
membranes (longer than 24 hours), maternal peripartum infection, premature delivery, low
birth weight, depressed respiratory function of the infant at birth or fetal anoxia, and septic or
traumatic delivery (1-3).
