Natures wonders: onboard virus protects bacteria (Introduction)

by David Turell , Monday, April 01, 2019, 17:18 (2061 days ago) @ David Turell

The trick is immune cells attack the virus but not the bacteria:

https://www.nature.com/articles/d41586-019-00991-4?utm_source=Nature+Briefing&utm_c...

"The virus, known as a phage, infects the Pseudomonas aeruginosa bacterium, which frequently resists antibiotic treatment. The phage prompts the immune system into going after it instead of its microbe host, researchers report1 on 28 March in Science. The bacterium and the phage, called Pf, exist in a symbiotic relationship that scientists suspect is more widespread in the microbial world than previously believed. The finding could help to explain why the immune system tolerates helpful bacteria, such as those in the gut, and could lead to better treatments for infections.

"Although some phages kill their bacterial hosts, others live happily inside the microbes without killing them. Researchers have long suspected that this coexistence means that the viruses are advantageous for the bacteria in some way.

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"The researchers found that 68% of the P. aeruginosa infections contained the Pf virus. When Bollyky and his colleagues transferred these phage-infected bacteria into open wounds on mice, they found that it took fewer bacteria to start an infection and that the rodents were more likely to die of their wounds than when the scientists used P. aeruginosa without Pf.

"The bacteria attracted immune cells called phagocytes, which eat bacteria but avoid viruses. When the phagocytes attacked wounds infected with P. aeruginosa and Pf, they soon left after eating only a few bacteria. The phagocytes that had ingested the infected bacteria then sent signals attracting immune cells that only attack viruses to the area.

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"Breck Duerkop, a microbiologist at the University of Colorado in Aurora, calls the finding “astounding”. He says that researchers will now be forced to think more broadly about the microbiome — the collection of bacteria in the human body. “I think it adds a layer of complexity to host–microbiome interactions that was largely overlooked.'”

Comment: If it doesn't hurt you, use it.