Observations, Science.

Bacteria talk to each other … new approach to antibiotics?

The old bacterial cell wall inhibitors, etc. are the antibiotics soon to be the past, obviously so because the bacteria have evolved means to defeat most of them, and we are out of good ideas to extend those methods, save at much too slow a pace. But much has been learned about bacteria in the past 20 years, and from this recent knowledge are born new points of attack!!!

-CC-BY-SA-3.0, Y_tambe

Diagram of quorum sensing. (left) In low density, the concentration of the autoinducer (blue dots) is relatively low and the substance production is restricted. (right) In high density, the concentration of the autoinducer is high and the bacterial substances (red dots) are produced.. Attrib: Y_tambe, CC-BY-SA-3.0.

Bonnie Brassler provides a fascinating lecture on this phenomenon, courtesy of TED: Bonnie Bassler on how bacteria “talk.” The bacterial communication under consideration here is not the long understood genetic exchange of information (plasmid exchange, conjugation, etc), but a new understanding of how bacteria exchange chemical messages via cell membrane surface receptors that trigger virulence, for example. This understanding provides entirely new ways of stopping bacterial diseases (block the virulence signal, no disease, for example), which is both species specific and general to whole classes of bacteria.

There is also a recent Scientific American article on the same subject: “Stopping Infections: The Art of Bacterial Warfare.” (Feb 2010 issue – this links to the abstract. If you have a SciAm digital subscription, you can view the entire article.). While it does not go into any depth on bacterial communication, it does describe other bacterial modes of attacking eukaryotic cells, which also seriously extends the points of attack for new antibiotics in additional directions.  A summary of the article:

  • Bacterial pathogens multiply and make toxins inside human hosts, but how the microbes elude our defenses and deliver their poisons have been poorly understood.
  • Studying host-pathogen inter­actions reveals sophisticated bacterial strategies for co-opting and manipulating host cells to serve a bacterium’s needs.

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