Cutting-Edge Technology Sheds Light on Antibiotic Resistance
Antibiotics work for most patients with a bacterial infection, but they may not for all infections. Public health agencies around the world are dealing with the growing challenge of bacterial resistance to antibiotics, which can make these medications ineffective.
The Centers for Disease Control and Prevention (CDC) reports that every year at least 2 million illnesses and 23,000 deaths in the United States are caused by antibiotic-resistant bacteria. The problem is especially serious for patients who have few viable antibiotic options; this can occur with certain types of serious bloodstream infections and with gonorrhea infections, among others.
Overuse of antibiotics in both humans and animals helps drive the evolution of resistant bacteria. Why? The bacteria have a natural tendency to mutate and to acquire genes from other bacteria. These changes can enable them to resist the antibiotics and flourish in environments where antibiotics are used. As the resistance genes move between bacteria, the bacteria themselves spread through soil, water, and wildlife. Over time, with continued antibiotic use, the situation worsens.
Resistance Spreading Globally
Scientists are concerned that resistant strains of bacteria could spread globally through travel or trade, including the exchange of foods. To help identify the presence of antibiotic-resistant bacteria as early as possible, and take steps to control their further spread, the FDA is using cutting-edge technology called whole genome sequencing (WGS).
A genome is an organism’s complete set of genes. In the 20 years since the first bacterial genome was completely sequenced, the science has advanced dramatically. The first bacterial genome sequence was uncovered in 1995 at a cost of several hundred thousand dollars and many months of work. Now it costs around $50 per genome and dozens can be done together overnight.
“For the first time, we can rapidly determine the entire collection of known antibiotic resistance genes in an individual bacterium. This is allowing new insights into the nature and magnitude of the resistance threat,” says Patrick McDermott, Ph.D., director of FDA’s National Antimicrobial Resistance Monitoring System (NARMS).
“And, because the database of resistance genes is growing, due to work by scientists around the globe, we can see what others are finding and quickly ascertain if resistance threats emerging in other countries also are present in the United States.”
Whole genome sequencing is also revealing new types of resistance genes in disease-causing bacteria, says McDermott. For example, NARMS data showed a rapid rise in gentamicin resistance in the foodborne bacteria, Campylobacter. Gentamicin is an antibiotic used to treat certain serious bacterial infections. WGS analysis showed that the genes causing this resistance are numerous, and most had never been seen before.