Listeria infection during pregnancy: A 10 year experience

Background: Although Listeria monocytogenes is widely distributed in nature, it rarely causes clinical infection in previously healthy people. This microorganism, however, may cause severe invasive disease in pregnant women and newborns. Objectives: To investigate - in our pregnant population - the impact, severity and outcome of listeriosis on both mother and fetus. Method: The study was carried out at a level III, university two-hospital complex. In a retrospective chart review of 65,022 parturients during a 10 year period (1990-1999), we identified and evaluated 11 pregnant patients and their offspring with Listeria infection. Results: Chorioamnionitis with multiple placental abscesses were observed in all five placentae examined. Clinically, 4 of 11 parturients had a cesarean section for fetal distress (36.3%), as compared to the 14% mean CS rate in our general population. Two of 11 had a late abortion (18.1%), as compared with the 4% rate in our hospital. Four of 11 had premature labor (36%), which was about four times the rate in our population. Finally, although no intrauterine fetal death was recorded in our series, there was one neonatal death of a term infant (1/11, 9%), which is about 10 times higher than our corrected perinatal mortality rate. Conclusions: If not promptly and adequately treated, listeriosis in pregnancy may present serious hazards to the fetus and newborn through direct infection of the placenta and chorioamnionitis.