Placental Listeriosis: Case Report and Literature Review.

Listeria monocytogenes, a foodborne, facultative, intracellular gram-positive bacillus, is one of 17 species of the Listeria genus and was responsible for the world's largest outbreak of listeriosis in 2017-2018 in South Africa. Listeria monocytogenes tends to cause mild gastrointestinal symptoms in healthy individuals. However, pregnancy-associated listeriosis can be fatal to the fetus and can lead to serious adverse effects in the neonate. Listeria monocytogenes has an affinity for the placenta, as opposed to other nonreproductive organs. Herein, we present a case of placental listeriosis diagnosed in a 33-year-old female, parity 4, with unknown gestational age during the listeriosis outbreak in South Africa in 2017-2018. The patient presented with pregnancy-related complications and underwent a caesarean section. Morphological features demonstrated acute suppurative villitis and intervillositis with a heavy load of gram-positive bacilli, which is highly suggestive of placental listeriosis. Multiplex polymerase chain reaction confirmed the presence of L. monocytogenes.