Science and Medicine: Bacteria

Washington Post staff writer David Brown and Carsten Matz, a microbiologist from the Helmholtz Centre of Infection Research in Brunswick, Germany, was online Tuesday, July 29 at 1 p.m. ET to answer questions about a recent study that shows bacteria can now detect each other.

Read David Brown's story: Social Lives of Bacteria May Yield Benefits for Humans (Post, July 29)

A transcript follows.

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David Brown: Good afternoon chatters! This is the Science chat about the story in Monday's Washington Post about biofilms. We are privileged to have on the chat, from German, Dr. Carsten Matz of the Helmholtz Centre for Infection Research, in Brauhschweig. He is the first author of an interesting study in PLoS ONE that was described in the article. He and his colleagues have discovered that when many bacterial species go into a biofilm state, they secrete toxic substances that kill their predators. So let's begin.

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Fallbrook, Calif.: Are you aware of the work of Professor Eshel Benm-Jacob, Professor of Physics, Israel; Past President of Israel Physical Society, Fellow of the American Physical Society and the World Institute of Physics; who made early disoveries of intelligence and cognition in baceria?

Please comment.

Bob Krone, Ph.D.

David Brown: Neither of us is aware of the work of Professor Benm-Jacob. If you would care to describe it briefly it might be of interest to other readers.

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Freising, Germany: You mention that an estimated 80 percent of chronic bacterial infections involve biofilms. Does this mean that infections like pneumonia, tuberculosis, streptococci and salmonella are usually caused by bacteria already in the slime phase?

Carsten Matz: Estimates vary between 60 and 80%. Pneumonia in cystic fibrosis patients is a classical example of a chronic biofilm infection by Pseudomonas aeruginosa producing a lot of slime. Streptococcus biofilms are responsible for dental caries. Infections by Salmonella or Mycobacterium tuberculosis are not caused by biofilms but are the result of the intracellular survival of these bacteria in host cells.

David Brown: Most acute bacterial infections, such as pneumococcal pneumonia, do not involve biofilms. Some chronic infections (such as taphylococcal infetions of prosthetic joints and native heart valves), however, do involve biofilms but start with bacteria in the free-floating, planktonic phase.

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Langley, Va.: Hi,

Although not specifically (unless I missed it?) mentioned in your article, is the formation of biofilm a mechanism by which MRSA transforms a relatively ubiquitous, non-pathogenic bacterium like S. Aureus into a potential killer?

Many thanks, R., DVM

David Brown: The ability of MRSA strains to produce infection and disease depends on numerous "virulence factors", some of which are involved in biofilm formation. For example, MRSA strains that cause chronic bladder infections in people with indwelling urinary catheters often have activated genes involved in biofilm formation. However, MRSA virulence is not simply a function of a strain's biofilm activity.

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Arlington, Va.: After travelling overseas I developed severe stomach pain, I was told that I probably have caught some kind of bad bacteria and I need to take "probiotics". That seems to help me, do you know how the "good bacteria" fights the bad one? There is a new test that detects "bad bacteria" by looking for its DNA instead of growing a culture, is this a reliable method? Thanks

Carsten Matz: Probiotic bacteria certainly help to restore the intestinal microbial flora after a severe infection. The intestinal flora can also be ragarded as a complex consortium of bacteria sitting on the epithelium in the form of a biofilm. Bacteria in these consortia cooperate and exchange metabolites as part of a symbiotic relationship. Probiotic bacteria re-establish the balance between component species. With the arrival of sequencing the DNA of entire microbial communities, we will soon be able to answer which bacteria are good or bad.

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Reston, Va.: A quick look at the Internet produces the following information that looks important to your area: ESHEL BEN-JACOB Professor of Physics The Maguy-Glass Chair in Physics of Complex Systems, Fellow of the American Physical Society,Former President of the Israel Physical Society

"Scientific American magazine placed Professor Eshel Ben-Jacob and Dr. Itay Baruchi's creation of a type of organic memory chip on its list of the year's 50 most significant scientific discoveries."

His homepage is: http://star.tau.ac.il/eshel/bacterial_linguistic.html

On it you can find links to the following: Bacteria Harnessing Complexity

Bacterial Linguistic Communication and Social Intelligence.

Bacterial Self-Organization: Co-Enhancement of Complexification and Adaptability in a Dynamic Environment.

Bacterial Wisdom, Godel's Theorem and Creative Genomic Webs.

David Brown: Thanks for this.

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Anonymous: Is it true that bacteria detect binary information (Toxic or Nuturing) about their immediate environment through their outer membrane rather than through their nucleus (or brain)?

Is the life of Bacteria similar to that of cells?

Carsten Matz: Bacterial chemotaxis involves sensory proteins in the cell membrane that sense the chemical gradient (of an attracting nutrient or a toxic repellant) with time and interact with intracellular proteins to affect the flagellar motor of the cell.

Many of the regulatory systems by which bacteria sense and then respond to environmental signals are called two-component systems, in a process called signal transduction which is similar to that of a eukaryotic cell. While the two-component systems regulates the gene transcription, in chemotaxis the signal transduction system regulates the activity of the gene products.

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David Brown: We have run out of questions so I think we'll stop. Once again, I want to thank Dr. Carsten Matz for participating in this session.

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