Placental invasion by actinomyces resulting in preterm delivery: a case report

Actinomyces is a gram-positive rod, some of which organisms are anaerobic and others which are facultative anaerobes. Most species of Actinomvces cluster together, forming a structure resembling a fungal colony. The organism is an opportunistic pathogen most commonly seen in the oral cavity but may also infect the gastrointestinal tract, lungs and uterus. Actinomyces is also a part of the normal vaginal flora and can result in infection independent of intrauterine device (IUD) use. Abscesses and swelling are common at the site of the infection. The organisms are grossly apparent by the formation of sulfur granules. Chorioamnionitis due to Actinomyces is exceptionally rare.

A 23-year-old woman delivered a male infant at 28 weeks' gestational age after premature labor. The mother had an unremarkable hospital course. There was no prior IUD history. The infant had an extended stay in the fetal intensive care unit secondary to prematurity. Evaluation of the placenta revealed necrotizing acute chorioamnionitis and organisms with a filamentous growth pattern. The morphology was consistent with Actinomyces spp.

This case is important because of the rarity of the infection. Clinicians and pathologists alike must be aware of this possibility even in the absence of IUD use.