Pregnancy-associated listeriosis: Clinical characteristics and geospatial analysis of a 10-year period in Israel

Background. Listeria monocytogenes is a foodborne pathogen that causes life-threatening infections in elderly, immunocompromised, and pregnant women. In pregnancy it may cause fetal loss or a preterm delivery, and the neonate is prone to neonatal sepsis and death. Methods. We created a cohort of all L. monocytogenes cases during 10 years (1998-2007) in Israel, by a comprehensive review of cases in hospitals throughout the country and cases reported to the Ministry of Health. Results. One hundred sixty-six pregnancy-related listeriosis cases were identified, resulting in a yearly incidence of 5-25 cases per 100 000 births. Presentation associated with fetal demise was more common in the second trimester (55.3%), and preterm labor (52.3%) and abnormal fetal heart rate monitoring (22.2%) were more common in the third trimester (P = .001). Fetal viability was low in the second trimester (29.2%) and much higher (95.3%) in the third trimester. Each additional week of pregnancy increased the survival chance by 33% (odds ratio, 1.331 [95% confidence interval, 1.189-1.489]). A single case of maternal mortality was identified. Listeria monocytogenes serotype 4b was more common in pregnancy-related than in non-pregnancy-related cases (79.5% vs 61.3%, P = .011). Pulsed-field gel electrophoresis analysis suggested that 1 pulsotype is responsible for 35.7% of the pregnancy cases between 2001 and 2007. This clone is closely related to the Italian gastroenteritis-associated HPB2262 and the invasive US Scott A L. monocytogenes strains. Conclusions. Our survey emphasizes the high rate of pregnancy-related listeriosis in Israel and shows that specific clones might account for this.