The majority of disease-causing bacteria in the body are rendered harmless by the protective effects of the immune system. Those that manage to escape the immune system can be killed by antibiotics, but bacteria are becoming more and more resistant to more and more antibiotics.
Now, Israeli scientists say that studying the predator-prey mechanisms of bacteria – or, their hide-and-seek game, if you will – could potentially generate alternatives to antibiotics.
Their proposition is based on the study of Bdellovibrio bacteriovorus, a bacterial predator that is an efficient killer of other bacteria, such as the prevalent E. coli. It is present in soil and, just like E. coli, it can also be found in the human gut, where a complex ecosystem of bacterial inhabitants exists.
This ferocious bacterial predator enters its prey and devours it from the inside. It can reach speeds of 160 micrometers per second, making it the “world champion” in speed swimming and 10 times faster than the E. coli.
Future development of potential alternatives to antibiotics
“Knowledge of defense and attack mechanisms in bacteria is crucial for future development of potential alternatives to antibiotics,” Dr. Daniel Koster of the Hebrew University of Jerusalem, said in a statement. “B. bacteriovorus kills bacteria by a whole different mechanism of action than antibiotics, and as such, predatory bacteria might in the future constitute a viable alternative to these antibiotics.”
Koster led the research together with scientists from The Hebrew University of Jerusalem and the Kavli Institute of Nanoscience at TU Delft in The Netherlands. The findings were recently published in the scientific journal Proceedings of the Royal Society B.
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“Predatory bacteria might be genetically modified to specifically target harmful bacteria”
In order to understand how E. coli is able to survive in the presence of such an effective predator, the researchers created two different environments for the B. bacteriovorus and E. Coli bacteria: The first one mimicked the features of soil, consisting of 85 tiny chambers, linked by a narrow channel; the second environment was an open space of a similar size, without the thin channel.
In the open environment, E. coli did not stand a chance to survive – most of the population was eliminated within a couple of hours. However, it proved surprisingly able to maintain a healthy population in an environment with many small chambers.
According to Koster, “groups of E. coli ‘hide’ in the many corners of the fragmented environment, where they readily stick as bio-films that probably protect them against B. bacteriovorus. Our findings provide important information because in natural environments, such as our gut, the bacterium also lives in fragmented spaces.”
It is not yet known precisely how E. coli is able to defend itself against predatory bacteria, but the research contributes to the understanding of the behavior of the predatory bacteria, which could become a possible alternative to antibiotics in the future.
“In the future, predatory bacteria might, for example, be genetically modified to specifically target harmful bacteria, while leaving benign bacteria untouched,” Koster says. “As such, B. bacteriovorus might be more selective than the antibiotics currently in use, and anti-bacterial treatment might not require the widespread extermination of the gut flora that is of importance to human health.”