A study by the Hebrew University that examined the struggle between predator and prey bacteria Shedding light on the development of a possible alternative to antibiotics in the future
The body's immune system destroys or neutralizes the harmful effect of most disease-causing bacteria in the body. Those that manage to escape the immune system may be eliminated by antibiotics. But one of the most difficult problems in modern medicine is the increasing development of bacteria resistant to an expanding range of antibiotics.
Get to know Bdellovibrio bacteriovorus - a predatory bacterium that effectively destroys Gram-negative bacteria such as E. coli, which are found in the digestive system. The predatory bacterium, less than a micrometer long, penetrates its prey, eats it from the inside while splitting into four or six offspring, explodes its prey and continues on its hunting trip. The speed of this bacterium is ten times greater than the E. coli, approximately 160 micrometers per second, a figure that places it in first place in the "world championship" in swimming.
"Understanding the defense and attack mechanisms of bacteria is critical for the future development of an alternative to antibiotics," explains Dr. Daniel Koster from the Department of Ecology, Evolution and Behavior at the Alexander Silverman Institute of Life Sciences at the Hebrew University.
Dr. Koster led the research in which scientists from the Hebrew University of Jerusalem and the Cavelli Institute at TU Delft in the Netherlands participated. "The Bdellovibrio bacteriovorus kills
bacteria by a mechanism of action completely different from that of classical antibiotics. As such, it may be a possible alternative to antibiotics, to which bacteria are increasingly developing resistance," he says. In order to understand how the E. coli survives in the face of such an effective predator, the researchers created two living environments for the bacteria, using a special technique of microfabrication - production in tiny dimensions of micrometers.
One - consists of 85 microscopic structures connected to each other through a narrow channel that allows the passage of bacteria. This structure simulates the composition of the soil. The second - is an open environment of a similar size, without division into cells and without the connecting canal.
The team of researchers, made up of experts in various fields - from microbiology to nanotechnology, from ecology to biophysics - published the results of their research in an article in the journal Proceedings of the Royal Society in which it was revealed that in the open field the ultrasonic did not survive, and most of the bacterial population was eliminated within a few hours. On the other hand and surprisingly, in an environment with many small cells, the E. coli maintained a healthy population and therefore survived.
Dr. Koster explained how E. coli survived in the divided environment: "We believe that groups of E. coli hide in different corners of the divided environment, and their grouping creates a layer of biological membrane (biofilm) that probably protects them from the predatory bacteria. The findings of our research provide important information that in natural environments, such as the one in the intestines, the bacterium also lives in fragmented spaces."
It is still not clear exactly how E. coli defends itself against the predatory bacteria, but the research contributes to a better understanding of the behavior of the predatory bacteria, which in the future may be a possible alternative to antibiotics.
"In the future, predatory bacteria may, for example, be genetically modified so that they focus on a targeted attack on the harmful bacteria, without also harming the harmless bacteria. Such selectivity is better than the antibiotics in use today, and an antibacterial treatment that does not completely destroy all the bacterial populations in the intestines, is of course better for human health."
