The Surprising Way Bacteria 'Talks' To Each Other

03/16/2014 11:25 EDT | Updated 05/16/2014 05:59 EDT

Amidst the myriad of political mechanisms, resistance is the most known. From grassroots picketing to national boycotts to a mass of millions congregating in a country's capital, the practice of protest is as old as civilization. Venturing into the resistance world brings an entirely unique experience, in which the participants not only have a different inner making, but they also speak a different language and work with one another to ensure that change is not only viable but, should it happen, sustainable.

In the world of infection, there is a similar type of resistance that has stymied researchers for decades. Antibiotic resistance, which is now rampant globally and portends the end of this weapon, continues to spread without any signs of cessation. At one time, this resistance was believed to be an individualistic feeling; when the situation was dire, their insides -- the genetics -- would change.

But recently, new revelations have shown that much like their human counterparts; these microbial revolutionaries also use both language and assistance to ensure change is enacted and maintained. Whereas humans use sound waves, print and visual media to convey their messages, bacteria use chemicals, proteins and other molecules. Although the nature is starkly different, the actual effect is surprisingly very similar.

Back in 1994, a team of researchers from Cornell University uncovered a rather unique means of communication between bacteria. Called quorum sensing, it was initially thought to be a means to identify the density of a bacterial population. The premise was simple. Every bacterium would release a series of chemicals all other bacteria could recognize. The concentration of the chemicals would then answer the question, "What's the population here?" If the population was high, the bacteria would thrive. If it was low, they would perhaps try to find another location to live.

Although this idea of cross talk was interesting, it would be another five years before researchers came upon a darker side to the conversation. In 2000, a team from the University of Nottingham revealed pathogens also spoke to one another. The question, however, changed to, "Hey, is this a good place to infect?" In the same year, two University of Rochester scientists suggested this question could also be exchanged between diverse bacteria, turning into, "Hey, can we start a city here?" When the answer was "Yes," the bacteria would work together to not only live, but also cause harm to the unfortunate human.

The development led to concern quorum sensing might be able to help bacteria develop not only a community, but also resistance, particularly against antibiotics. There had been some evidence of this in the laboratory environment however there had been no identification of such in the human body. With further testing, the assistance was confirmed. In 2005, a UK group all but put any doubt to rest; bacteria used quorum sensing to tell each other, "We need to resist!"

While the call to rise was known, there was still no way to understand how bacteria actually conducted the revolt. But this week, a team from the United Kingdom unveiled how it might very well occur. The key was not about finding out how everyone was doing, but how the individual bacterium might be able to help the cause.

The team took a well-known quorum sensing bacterium, Pseudomonas aeruginosa, placed it into a number of different environments, and looked for series of chemical messages. What they found was a complex interaction in which healthy environments led to less talking. If times were good and there was no need for an uprising, everyone stayed calm. Yet, as the environment worsened, there was endless chatter. In the context of the experiment, talking was not only limited to social interaction; it was also based on how easy life could be. When it comes to infection and antibiotic resistance, however, the results suggest there is more to the story.

The results suggested bacteria are continually in communication with one another. When times get dire, they attempt to find anyone who might have resistance and be willing to pass it on. Once there is a yes, a crowd appears, all hoping for the same gift. Once they get it, they head off to do the same. Much like a single candle flame can light an entire vigil, a single bacterium can turn a susceptible population to full resistance.

The rather glum outlook of resistance communication suggests that public health officials have one more problem in the fight against antibiotic resistance. However, there is a way forward. Last year, a team of researchers from the University of Illinois at Chicago highlighted a large number of naturally formed molecules that interfere with bacterial communications. Familiar names such as turmeric, goldenseal, cinnamon and even the probiotic bacterium, Lactobacillus, all possessed the ability to thwart malicious microbes. This offers at least hope to minimize the chances for even more resistant bacterial strains and keep the current revolution from spreading any further.


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