The Antibiotic Arms Race: Are We Gaining Ground?
“We need to increase health literacy so people know what a virus, bacterium, and antibiotics are.”
- Georges Benjamin, Executive Director, American Public Health Association
If you are a regular reader of Germ Gems, you may recall an earlier post on September 30, “The Antibiotic Discovery Pipeline: Will It Run Dry?”. It appeared just two days after the 91st anniversary of Alexander Fleming’s discovery of penicillin. While penicillin was quickly recognized as a “miracle drug,” Fleming warned, if it wasn’t used judiciously bacteria resistant to its action would emerge. His prescience was rapidly realized, and the September 30 blog dealt mainly with the race between bacteria acquiring resistance and the ingenuity of researchers in academia and the pharmaceutical industry to develop new antibiotics.
So why another blog on the topic of antibiotic resistance? Two reasons: 1) antibiotic resistance remains the single biggest global infectious disease threat, and 2) publication on November 13 of a report from the Center for Disease Control and Prevention (CDC): Antibiotic Resistance Threats in the United States, 2019.
Highlights of the CDC’s report include the staggering numbers of Americans that are affected: antibiotic-resistant bacteria and fungi cause more than 2.8 million infections and 35,000 deaths in the U.S. each year. The report lists 18 different types of antibiotic-resistant bacteria and fungi and assigns each of them to one of three levels of concern to human health—urgent, serious, and concerning. All of these microbes are what are popularly called “superbugs,” that is, they are resistant to two or more classes of antibiotics (and in some cases, all antibiotics).
But the CDC’s report also includes some good news. Since its initial report in 2013, the critical actions and investments against antibiotic resistance launched by the CDC, the World Health Organization, other public health and non-profit organizations, and the pharmaceutical industry are paying off. As stated by the CDC Director Robert Redfield, M.D., “Today’s report demonstrates notable progress, yet the threat is still real. Each of us has an important role in combating [antibiotic resistance]. Lives here in the United States and around the world depend on it.”
Dr. Redfield’s reference to “each of us” isn’t aimed just at prescribers of antibiotics and public health officials but rather encompasses everyone—all adults in the general public. While the full CDC report on antibiotic resistance is important reading for infectious disease specialists and other healthcare providers, I believe there are two take-home messages for non-medical readers.
Take-home message number 1: In keeping with Georges Benjamin’s recommendation quoted at the beginning of this blog: know what a virus, bacterium, and antibiotics are. By definition, both viruses and bacteria are microscopic creatures (although to see most viruses a special type of very powerful microscope, called an electron microscope, is required). And the simple definition of an antibiotic is a drug used to treat bacterial infections. Antibiotics have no effect on viral infections.
The reason that knowing these definitions is crucial is that an estimated 44% of outpatient antibiotic prescriptions are written to treat patients with acute respiratory conditions that are caused in a vast majority of instances by viruses, such as, sinus infections, middle ear infections, pharyngitis, viral upper respiratory infections (i.e., the “common cold”), bronchitis, and influenza. Because the overuse of antibiotics is a major driver of antibiotic resistance, emphasis needs to be placed on eliminating antibiotic prescriptions for these conditions.
So, if your healthcare provider tells you that you have a viral infection and that you don’t need an antibiotic, you should be thankful. (Not only will you be participating in reducing the emergence of antibiotic resistance, but you also will be spared the side effects and costs that come with all antibiotics.)
Take-home message number 2: Give credit to animal food providers who eliminate antibiotics from animal feed. It is estimated that between 70-80% of all medically important antibiotics in the U.S. are sold for use in animals. Just as the overuse of antibiotics in humans fosters an emergence of antibiotic-resistant bacteria, so too do antibiotics that are given to animals (primarily poultry, pigs, and cattle) to promote their growth, that is, fatten them up.
In 2017, the Food and Drug Administration (FDA) issued new rules prohibiting antibiotic use for animal growth promotion. The good news is that this form of antibiotic stewardship on the farm is working. I believe we should applaud the FDA and compliant food providers when we see products labeled “antibiotic-free.” Not only does this measure reduce the amount of antibiotics in the environment, but it also decreases the chances that you might pick up an antibiotic-resistant bacterium from the food you eat.
Why can’t we win the war on antibiotic resistance? Antibiotic resistance is a prime example of evolution in action. Bacteria are the earliest form of life on Earth, arising about 3.8 billion years ago. Like all life forms, bacteria compete for survival. And development of genes that confer resistance to antimicrobial products in their environment provides bacteria a survival benefit. That means this is a formidable problem as our enemies have been working on it for billions of years.
Given this evolutionary background, it’s not surprising that antibiotic resistance genes are everywhere. For example, penicillin-resistant bacteria have been isolated from people living in remote tribes with no contact with modern civilization (or our antibiotics). The results of a study of ancient DNA from 30,000-year-old Beringian Permafrost demonstrated that antibiotic resistance is a natural phenomenon that predates modern selective pressure of clinical antibiotic use. In another study, researchers from the University of Lyon in France analyzed DNA sequences from 71 different environments, including human feces, chicken guts, the ocean, and even Arctic snow. Every environment they tested harbored an abundance of antibiotic-resistance genes.
The search for or attempts to synthesize antibiotics that can withstand the relentless evolution of bacterial resistance seems a fool’s errand. Nevertheless, as was mentioned in the September 30th blog, the pharmaceutical industry has made progress in recent years in providing new antibiotics that work against resistant bacteria. Coupled with measures aimed at reducing antibiotic use in the clinic and farmyard, we have a chance of staving off our enemies, if not conquering them.