A molecular portrait of maternal sepsis from Byzantine Troy

Pregnancy complications are poorly represented in the archeological record, despite their importance in contemporary and ancient societies. While excavating a Byzantine cemetery in Troy, we discovered calcified abscesses among a woman's remains. Scanning electron microscopy of the tissue revealed 'ghost cells', resulting from dystrophic calcification, which preserved ancient maternal, fetal and bacterial DNA of a severe infection, likely chorioamnionitis. <i>Gardnerella vaginalis</i> and <i>Staphylococcus saprophyticus</i> dominated the abscesses. Phylogenomic analyses of ancient, historical, and contemporary data showed that <i>G. vaginalis</i> Troy fell within contemporary genetic diversity, whereas <i>S. saprophyticus</i> Troy belongs to a lineage that does not appear to be commonly associated with human disease today. We speculate that the ecology of <i>S. saprophyticus</i> infection may have differed in the ancient world as a result of close contacts between humans and domesticated animals. These results highlight the complex and dynamic interactions with our microbial milieu that underlie severe maternal infections.