People have been using antibiotics for nearly 2000 years, suggests a new study, which found large doses of tetracycline embedded in the bones of ancient African mummies.
What's more, they probably got it through beer, and just about everyone appears to have drank it consistently throughout their lifetimes, beginning early in childhood.
While the modern age of antibiotics began in 1928 with the discovery of penicillin, the new findings suggest that people knew how to fight infections much earlier than that — even if they didn't actually know what bacteria were.
Some of the first people to use antibiotics, according to the research, may have lived along the shores of the Nile in Sudanese Nubia, which spans the border of modern Egypt and Sudan.
"Given the amount of tetracycline there, they had to know what they were doing," says lead author George Armelagos, a biological anthropologist at Emory University in Atlanta. "They may not have known what tetracycline was, but they certainly knew something was making them feel better."
Armelagos was part of a group of anthropologists that excavated the mummies in 1963. His original goal was to study osteoporosis in the Nubians, who lived between about 350 and 550 A.D. But while looking through a microscope at samples of the ancient bone under ultraviolet light, he saw what looked like tetracycline — an antibiotic that was not officially patented in modern times until 1950.
At first, he assumed that some kind of contamination had occurred.
"Imagine if you're unwrapping a mummy, and all of a sudden, you see a pair of sunglasses on it," says Armelagos. "Initially, we thought it was a product of modern technology."
His team's first report about the finding, bolstered by even more evidence and published in Science in 1980, was met with lots of scepticism. For the new study, he got help dissolving bone samples and extracting tetracycline from them, clearly showing that the antibiotic was deposited into and embedded within the bone, not a result of contamination from the environment.
The analyses also showed that ancient Nubians were consuming large doses of tetracycline — more than is commonly prescribed today as a daily dose for controlling infections from bad acne. The team, including chemist Mark Nelson of Paratek Pharmaceuticals, reported their results in the American Journal of Physical Anthropology.
They were also able to trace the antibiotic to its source: grain that was contaminated with a type of mold-like bacteria called Streptomyces. Common in soil, Strep bacteria produce tetracycline antibiotics to kill off other, competing bacteria.
Grains that are stored underground can easily become moldy with Streptomyces contamination, though these bacteria would only produce small amounts of tetracycline on their own when left to sit or baked into bread. Only when people fermented the grain would tetracycline production explode. Nubians both ate the fermented grains as gruel and used it to make beer.
The scientists are working now to figure out exactly how much tetracycline Nubians were getting, but it appears that doses were high that consumption was consistent, and that drinking started early. Analyses of the bones showed that babies got some tetracycline through their mother's milk.
Then, between ages two and six, there was a big spike in antibiotics deposited in the bone, Armelagos said, suggesting that fermented grains were used as a weaning food.
Today, most beer is pasteurised to kill Strep and other bacteria, so there should be no antibiotics in the ale you order at a bar, says Dennis Vangerven, an anthropologist at the University of Colorado, Boulder.
But Armelagos has challenged his students to home-brew beer like the Nubians did, including the addition of Strep bacteria. The resulting brew contains tetracycline, tastes sour but drinkable, and gives off a greenish hue.
There's still a possibility that ancient antibiotic use was an accident that the Nubians never knew about, though Armelagos has also found tetracycline in the bones of another population that lived in Jordan. And VanGerven has found the antibiotic in a group that lived further south in Egypt during the same period.
Finding tetracycline in these mummies, says VanGerven, is "surprising and unexpected. And at the very least, it gives us a very different time frame in which to understand the dynamic interaction between the bacterial world and the world of antibiotics."