New Genetic Test for Antimicrobial Resistance

how-bacteria-work-360x240You’ve most likely taken an antibiotic at least once in your lifetime. From treatments for painful strep throat or ear infections as a child, to burning urinary tract infections or itchy skin infections, antibiotics are one of the most highly utilized and important medication classes we have.  Soon, your doctor may have a new weapon in their arsenal to diagnose and target treatment:  scientists at American University have developed a rapid, highly sensitive genetic test to determine whether bacteria carry a gene that causes resistance to two common antibiotics. Their research, published in BMC Infectious Diseases, demonstrated that the new test works as accurately as culture-based methods but gives results in minutes, not hours or days.

The new rapid test developed by the AU team identifies bacteria carrying the Macrolide efflux gene A, which causes resistance to two widely used antibiotics: erythromycin and azithromycin. Azithromycin is one of the top ten most prescribed antibiotics in the United States, used to treat a wide variety of bacterial infections such as strep throat and ear infections.

“The test is able to detect the gene within 10 minutes,” said John R. Bracht, assistant professor of biology at American University and corresponding author on the study. “Standard antibiotic testing requires at least an overnight culture and often isn’t performed in routine diagnostic work. Instead, physicians guess which antibiotic to prescribe based on past experience and recommendations, and patients have to return if the treatment fails. We simplified the process of detecting antimicrobial resistance so a physician can determine whether or not a patient will be resistant to a prescribed drug while that patient is still in the waiting room.

We think this is a game-changer for treating common illnesses.”

– John Bracht, assistant professor of biology at AU

Although there is widespread resistance to azithromycin and erythromycin, they remain two of the most prescribed treatments for a variety of conditions.  The use of an antibiotic that bacteria are resistant to is not only ineffectual, but potentially creates “superbugs” that are extremely difficult to treat.  The new genetic test might lead to better outcomes by prescribing targeted care, removing some of the trial and error associated with antibiotics.

The rise of antibiotic-resistant bacteria is a growing problem in the United States and the world. In the U.S. annually, more than 2 million people get antibiotic resistant infections and at least 23,000 people die, according to the Centers for Disease Control and Prevention. The U.S. National Institutes of Health, CDC, World Health Organization, and United Nations have prioritized the issue. However, tracking antimicrobial resistance is a significant challenge, the researchers write, since available culture-based methods are slow and expensive.

The full impact of worldwide antibiotic resistance is unknown, since there are no mechanisms in place to track resistance worldwide.  What is clear, however, is that this problem could render one of the most important medical advancements in human health obsolete, turning common infections into deadly threats.

The new rapid test addresses this challenge, making tracking antibiotic resistance quick, easy, and routine. It offers scientific researchers a way to monitor the prevalence and movement of antimicrobial drug resistance. The next step for the AU team to getting the test into doctors’ offices is to obtain approval for use of the test from the U.S. Food and Drug Administration.