Airborne bacteria may offer clues about how antibiotic resistance develops
New research from Rutgers’ and other scientists suggests bacteria can live and spread for thousands of miles through the air and across the globe and is not transmitted only through people and animals, as once thought. Referred to as the “air bridge,” the researchers said this discovery may reveal another way antibiotic resistance develops. The findings were reported Sunday in Rutger’s Today.
“Our research suggests that there must be a planet-wide mechanism that ensures the exchange of bacteria between faraway places,” said senior author Konstantin Severinov, a principal investigator at the Waksman Institute of Microbiology and professor of molecular biology and biochemistry in the School of Arts and Sciences at Rutgers University-New Brunswick.
According to the Rutger’s article, scientists gathered what is called Thermus thermophilus bacteria from hot gravel on Mount Vesuvius and hot springs on Mount Etna in Italy; hot springs in the El Tatio region in northern Chile and southern Chile’s Termas del Flaco region; and hot springs in the Uzon caldera in Kamchatka, Russia.
“Because the bacteria we study live in very hot water – about 160 degrees Fahrenheit – in remote places, it is not feasible to imagine that animals, birds or humans transport them,” Severinov said. “They must be transported by air and this movement must be very extensive so bacteria in isolated places share common characteristics.” Severinov and other researchers studied the "molecular memories" of bacteria from their encounters with viruses, with the memories stored in bacterial DNA, according to the study, which appears in the journal Philosophical Transactions of the Royal Society B.
Bacteriophages, otherwise known as viruses of bacteria, are the most plentiful forms of life found on earth and considered extremely influential on “microbial populations, community structure and evolution.”
According to the study, when bacterial cells become infected by viruses those molecular memories live in areas of bacterial DNA called CRISPR arrays. If a cell survives an infection it then transfers the memories – small pieces of viral DNA – to its offspring, allowing scientists to follow the history of bacterial interaction with viruses over time. The researchers had originally thought bacteria from the same species living thousands of miles apart would carry different memories of interacting with viruses and evolve in different ways since they lived so far apart.
On the contrary, “What we found, however, is that there were plenty of shared memories – identical pieces of viral DNA stored in the same order in the DNA of bacteria from distant hot springs,” Severinov said. “Our analysis may inform ecological and epidemiological studies of harmful bacteria that globally share antibiotic resistance genes and may also get dispersed by air instead of human travelers.”
Now the scientists would like to look at bacteria in the air from different altitudes and locations using planes, drones or research balloons. The study included scientists at the Russian Academy of Sciences; Skolkovo Institute of Science and Technology in Russia; Pasteur Institute in France; University of Santiago de Chile; and Weizmann Institute of Science in Israel.
