Petri Dish: The antibiotics problem
Special to the Daily
The bacterium that causes tuberculosis thrives in the lungs and is spread from person to person through the air. Many patients’ immune systems are able to wall off the pathogen, effectively halting the infection. But in others, fortunately a minority, the bacteria manage to replicate extensively, causing irreparable damage to the lungs and eventually death. The lucky patients who are able to wall off the bacteria are not cured, since live bacteria persist in a dormant form and can subsequently re-emerge from their prison to cause disease, especially later in life when the lung’s immune defenses decline. It may be hard to believe, but approximately one-third of the world’s entire human population, more than 2 billion people, is infected with TB bacteria and harbors the bugs in their inert form.
Antibiotics (antibacterial drugs) have been the main line of defense in the global control of TB. But in recent years, strains of TB bacteria have emerged that are increasingly resistant to even the most powerful antibiotics available. The end result will be a strain of TB simply not controlled by modern drugs, taking us back to the early 20th century when TB was a feared disease across the globe. Surprisingly, relatively little emphasis has been placed on developing new types of antibiotics, primarily due to the lack of sufficient financial incentives for pharmaceutical and biotech companies.
TB is not the only disease for which the decreasing efficacy of antibiotics is a problem. Recent years have seen the emergence of several antibiotic-resistant pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA), which causes a range of illnesses. Of particular concern is Klebsiella pneumonia, which can live in the intestines and has developed strains that are resistant to essentially all antibiotics available. The World Health Organization has warned of the significant threat posed by the spread of these antibiotic-resistant diseases. And in the U.S., the Centers for Disease Control has recently estimated that over 2 million people are infected with antibiotic-resistant bacteria annually, resulting in 23,000 deaths. It appears that we are entering a new phase of medicine characterized by our inability to control many common bacterial infections, not dissimilar to the state of medicine in the last century. Moreover, this is a problem that transcends borders and impacts rich and poor countries alike.
As pharmaceutical companies and researchers ponder the antibiotics problem, it is worth noting that the CDC has reported that about half of all human antibiotic use is unnecessary. For example, the inclusion of antibiotics in soaps and wipes is completely unnecessary, and its use in various ointments is questionable. The failure of patients to completely finish a course of antibiotics once they start to feel better also is a significant problem. Furthermore, antibiotics are extensively used in the livestock industry to enhance food production; much of this use is considered unnecessary. This general overuse of antibiotics is almost certainly increasing the rate at which bacteria acquire resistance.
The solution to the antibiotic problem lies in the development of brand-new classes of antibiotics. This requires a different mindset from the past where antibiotic development focused primarily on the modification of existing drugs to improve their efficacy. In fact, there has not been a truly new antibiotic (with a new mode of action) for over 25 years.
So where will we find truly novel antibiotics? In a recent issue of the Petri Dish, I mentioned the possibility that a type of bacteria referred to as archaebacteria might be a valuable source of new antibiotics with novel modes of action.
Another source of novel antibiotics may be our own bodies. A recent article in The New York Times highlighted findings by scientists studying the microbes that live in our guts, referred to as the microbiome. They identified genes for more than 3,000 unidentified molecules, many of which may be the basis of new drugs. It turns out that the microbes that live in our guts are constantly competing for space and essentially wage war against one another by secreting powerful drugs that kill competing bacteria.
While health authorities confront the problem, we can all make an impact by demanding that the food industry stop using antibiotics unnecessarily and by avoiding antibiotic-laced over-the-counter products. We can also make sure that we always finish any courses of antibiotics prescribed to us. All of this will help prevent our descent back into the infectious disease challenges of the past, including the re-emergence of tuberculosis.
David L. “Woody” Woodland, Ph.D., is the chief scientific officer of Silverthorne-based Keystone Symposia on Molecular and Cellular Biology, a nonprofit dedicated to accelerating life science discovery by convening internationally renowned research conferences in Summit County and worldwide. Contact Woody at (970) 262-1230, ext. 131, or firstname.lastname@example.org.
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