Developing weapons to fight our tiniest adversaries
Kills 99.9% of bacteria.
Walking through the household cleaner aisle of your neighborhood grocery store you see this phrase printed among the bottles of cleaners. Disinfectants make this claim to tout their effectiveness against killing bacteria, and yet this phrase still suggests that a small percentage may survive. When it comes to household cleaners, the remaining 0.1% of bacteria is not a cause for worry. But when it comes to the overuse of antibiotics in society, this 0.1% can easily balloon into a rather large problem. Like household cleaners, antibiotics are rarely effective against every single bacterial cell encountered. The surviving bacterial cells, if allowed to proliferate, could eventually result in a strain of antibiotic-resistant superbugs.
Antibiotic-resistant superbugs are an increasingly common problem in the United States due to the severe overuse of antibiotics. These bacteria have learned how to defend themselves against the antibiotics we routinely used. As a result, infections from these bacteria are extremely difficult to treat, resulting in 35,000 deaths each year. The CDC recognizes resistant bacteria as a major threat in the U.S., driving scientists to explore means to effectively combat bacteria in new ways the germs cannot easily overcome.
But how are these microbes evading the antibiotics? Bacteria are constantly acquiring random mutations in their DNA. These mutations may help or hurt the bacteria and ones that help the bacteria survive are passed on. If a strain of bacteria is regularly exposed to antibiotics, eventually the only bacteria left will be ones with genes granting them resistance to the antibiotics. These remaining bacteria will then proliferate into a new superbug strain.
Efforts to prevent the misuse and overuse of antibiotics will minimize the emergence of superbugs. However, wouldn’t an antibiotic-like drug that cannot result in the emergence of superbugs be ideal? Scientists are researching methods of preventing and treating bacterial infections that do not involve killing the bacteria, but rather inhibiting their infectious abilities. By not killing the bacteria, those with special resistance genes against the drug will not have any survival advantage over bacteria affected by the treatment. With no survival advantage, any resistant bacterial cells will not easily proliferate and pass on their genes.
In one instance, researchers are investigating blocking the molecules that allow E. coli, the bacteria responsible for most urinary tract infections, to bind to human cells. Researchers predict that by preventing the bacteria from binding to human cells, they will prevent urinary tract infections with minimal risk of inadvertently creating resistant bacteria. If the bacteria are unable to bind to human cells, they will simply be washed out of the body when the person uses the bathroom.
The use of antibiotics gave humanity an advantage in the war against microbes. Yet bacteria are figuring out ways to fight back. To stay ahead of this microscopic arms race, we must develop new ways to combat infections that do not inadvertently make them stronger.
Laura Carlucci is a grad student in the Department of Bioengineering at the University of Washington. She is studying how mechanical forces affect binding between molecules and the mechanism behind a particularly force-resistant interaction found in nature.