Calcified nodule found among the skeletal remains at Troy. (A) Burial x24.177 (grave 14, cemetery in quadrat x24). Photo credit Gebhard Bieg, 2005. (B) Cross-section of nodule (sample no x24.177), photo credit: Pathologie Nordhessen 2009. Scale represents 1 cm. (C) Location of Troy. Modern day Turkey is shaded in gray. Credit: Pepperell et all. eLife journal.

The woman died at the time of pregnancy, around the age of 30. She was buried in the remains of the legendary city of Troy, some 800 years ago.

But her calcified “ghost cells” have given intimations of her final suffering – and also about the hardscrabble life of this woman, eking out an existence at the wane of the Byzantine Empire, according to a new study in the journal eLife.

Two nodules the size of strawberries were analyzed just below the ribs. Inside those nodules were the microfossil “ghosts”: immaculately preserved bacteria from the genus Staphylococcus, and an ancient variety of Gardnerella vaginalis. Together the two likely caused her death from sepsis, write the authors.

“There was something really interesting about the way this material was preserved,” said Caitlin Pepperell, of the University of Wisconsin – Madison, one of the authors. “The quality of the (genetic) data is unparalleled.”

The nodules indicated the woman was likely pregnant – mineralized within the calcium was DNA of the woman, plus a Y chromosome that was likely from her male fetus, according to the scientists.

The bacteria was also locked in there, like a time capsule, they added. The majority of genetic material was the Staphylococcus germ.

The ancient strain of Staphylococcus saprophyticus was one more closely linked to germs found in today in livestock. (The human strains today are predominantly known for causing urinary tract infections in females). The ancient strain resembles parts of the current animal and human varieties of the germs, potentially because the peasants of the Byzantine Asia Minor typically lived with their livestock in close proximity.

“The strain from Troy belongs to a lineage that is not commonly associated with human disease in the modern world,” Pepperell said. “We speculate that human infections in the ancient world were acquired from a pool of bacteria that moved readily between humans, livestock and the environment.”

Only a short list of ancient bacteria has been sequenced through remains, a list that includes strains of cholera, tuberculosis, leprosy and bubonic plague.

“In this case, the amount and integrity of the ancient DNA was extraordinary,” Pepperell added. “Calcification made little tiny suitcases of DNA and transported it across an 800-year timespan.”