Bacteria’s Secret Language

by Mathew Lipkin

Predating modern humans by millions of years, bacteria are some of the world’s oldest living organisms. While to the naked eye they are invisible and often forgotten, each person is constantly interacting with them. According to microbiologist Dr. Bonnie Bassler, while there are about a trillion human cells that make up the human body, approximately 10 trillion bacteria are in you or on you at any point in time. From birth all the way until death, beneficial bacteria play a variety of vital roles from digesting the food you eat and making your vitamins to teaching your immune system to detect disease-causing microbes. Though each bacterium is too small to impact a person on its own, quorum sensing allows them to have a collective impact on your health.

Quorum sensing is a recently-discovered chemical language that exists amongst bacteria. Previously, bacteria were considered to be antisocial organisms, but new research suggests that they communicate with each other through chemical signals. Unfortunately, while this language proves useful to the good bacteria that live within us, it also is used by the plethora of pathogenic bacterial invaders that inhabit our bodies and the environments around us. On its own, a single bacterium releasing toxins would have no effect on the comparatively large human body. Through quorum sensing, however, groups of bacteria are able to detect when there are enough of their own kind to at least temporarily compromise the immune system.

Often, antibiotics are used to fight infections caused by these bad bacteria. When working effectively, antibiotics kill bacteria. Yet due to the mechanisms of survival of the fittest, bacteria that incur random genetic mutations protecting against antibiotics live on to reproduce. This creates vast populations of antibiotic-resistant bacteria. Since bacteria multiply at a significantly faster rate than humans can develop new antibiotics to fight off the resistant species, the global community is running out of effective medicines to combat bacterial disease. A report published by the World Health Organization stated that “Of the 33 potential medicines for treating priority bug infections … at best … 25 will serve as short-term solutions since it is expected bacteria will quickly adapt to and resist.”

Fortunately, quorum sensing can be co-opted to present an alternative method of treatment. Research suggests that if we can develop a way to block the signaling molecule detectors, or receptors, of disease-causing bacteria, then we can render them essentially “deaf.” If we can find a way to prevent them from communicating, bacteria would be unable to recognize when there are enough of them to launch a pathogenic attack. This treatment mechanism is being tested in P. aeruginosa. These bacteria can cause both acute and chronic infections in humans – most significantly in cystic fibrosis, which inhibiting lung function and increasing chances of mortality. Using quorum-sensing factors, these bacteria are able to collectively attain pathogenicity. If a drug was created to block the bacteria’s receptors, they would be unaware of each other and thus such serious infections could be prevented or cured. While there are currently several medicines in development, none are on the market at the moment due to the novelty and complexity of this treatment method.

Once these medicines are eventually created, the receptor blocking mechanism could remain effective for much longer periods of time than antibiotics. Because the drugs do not directly kill bacteria, the chances of resistant strains developing through evolution would be much slimmer. This elongated effectiveness also has the potential to lower drug costs because if pharmaceutical companies do not have to constantly research and develop new medicines, they could lower prices. With these new advances, the medical community can eventually phase out antibiotic use. Countless lives could be saved as bacterial infections become a thing of the past.