Seeing how bacteria acquire new genetic information can help scientists better understand antibiotic resistance and how to fight it.
At least 2 million people are infected with antibiotic-resistant bacteria each year, according to the Centers for Disease Control and Prevention, making conventional drugs less effective in treating bacterial infections. The World Health Organization found strains of antibiotic-resistant bacteria in nearly 490,000 people suffering from tuberculosis and 500,000 people with other infectious diseases.
When bacteria die, their DNA material can be absorbed by other bacteria. Incorporating that DNA into a gene is known as natural transformation, a mechanism of horizontal gene transfer, which lets bacteria take on new traits such as antibiotic resistance. For the first time, scientists at Indiana University observed how bacteria use harpoon-like appendages to grab bits of DNA from their surroundings and reel them back into their own bodies for absorption, just as though the bacteria had gone fishing.
In their study, published last month, the researchers dyed Vibrio cholerae, the bacteria that causes cholera. They watched the bacteria grabbing nearby DNA using the tip of surface appendages called “competence pili” and pulling the DNA back into their bodies through surface pores. Fluorescent dye made the pili—which is more than 10,000 times thinner than human hair—visible.
Researchers are hopeful that better understanding the spread of antibiotic resistance may allow scientists to develop new ways to fight it.
“It’s important to understand this process, since the more we understand about how bacteria share DNA, the better our chances are of thwarting it,” said Ankur Dalia, an assistant professor of biology at Indiana University. —Harvest Prude