Like other skeletons in the cemetery, the remains bore the unmistakable signs of the hard agrarian lifestyle of the ancient farming community on the outskirts of what was once the ancient world’s fabled city of Troy. The skeleton was a woman about 30-years-old, and she had been laid to rest in a stone-lined grave.
According to Science Daily, Henrike Kiesewetter, an archaeologist affiliated with Project Troia at Tüebingen University said that two calcified nodules at the base of the skeleton’s chest, just below the ribs, caught her eye. Each was the size of a strawberry.
“The preliminary thought was that these were tubercles arising from tuberculosis,” says Caitlin Pepperell, a University of Wisconsin-Madison expert on the evolution of pathogens and a professor of medicine and medical microbiology. Tuberculosis is often characterized by the growth of calcified nodules.
But after cracking open the nodules, the researchers discovered instead, well-preserved microfossils, mineralized “ghost cells,” that closely resembled bacteria from the genus Staphylococcus. This genus includes the highly pathogenic species, S. aureus.
The nodules were sent to McMaster University’s Hendrik Poinar, an expert in ancient bacterial DNA. “Amazingly, these samples yielded enough DNA to fully reconstruct the genomes of two species of bacteria, Staphylococcus saprophyticus, and Gardnerella vaginalis, which infected the woman and likely led to her death,” says Poinar, according to Fox News.
But here’s what really amazing — The nodules nor only contained the bacterial DNA, but the DNA of the woman and what looks to be her male fetus. But 31 to 58 percent of the DNA came from the bacteria responsible for her death.
In the study published in the journal eLife, the team led by Pepperell and Poinar provides a molecular portrait of the fatal infection. Their findings add to our knowledge about the complications that can occur during pregnancy in ancient and contemporary societies, as well as the niche Staphylococcus saprophyticus occupied in a society where it was common for people to cohabit with animals.
The researchers believe S. saprophyticus belongs to a lineage that does not appear to be commonly associated with human disease today. 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.”
