Nocardioform placentitis with isolation of Amycolatopsis spp in a Florida-bred mare.

This study reports the rare case of a Thoroughbred mare that experienced complicated postpartum outcomes due to an infection called nocardioform placentitis, caused by Amycolatopsis spp. The disease typically found in the Kentucky region, but in this case, it was observed in a Florida-bred mare, suggesting it could be an emerging disease.

Findings and Methodology

• The study focuses on a 4-year-old Thoroughbred mare which was found to have placental abnormalities as well as a retained placental remnant. A Microbial culture of the mare’s placenta showed pure growth of a bacterium known as Amycolatopsis spp.
• Histological examination of the placenta revealed a condition known as chorionitis, which is an inflammation of the outermost layer of the fetal membrane. Along with that, filamentous gram-positive bacilli were found inside the inflamed area.
• The observation also found multifocal allantoic adenomatous hyperplasia on the allantoic surface, which is a benign tumor of glandular origin.

Treatment and Outcome

• The mare was treated with lavage (a cleaning process to wash out an organ or body cavity) and oxytocin which resulted in the expulsion of the placental remnant within a few hours after giving birth. However, despite this treatment step and multiple breedings, the mare did not become pregnant again.
• The offspring from this pregnancy initially appeared healthy but unfortunately died at 7 weeks old due to complications arising during an elective surgical procedure.

Significance and Conclusions

• Previously confirmed cases of nocardioform placentitis have been mainly reported in mares bred in the central Kentucky region. This is the first instance, to the author’s knowledge, that the disease has been identified in a Florida-bred mare. Additionally, the isolated pathogen in this case was a different species from the one seen in Kentucky, indicating this could be an emergent disease.
• The clinical signs manifested by mares with nocardioform placentitis differ from those of mares suffering from placentitis resulting from an ascending pathogen.