A bacterium which is responsible for about 10% of hospital-acquired infections in the US uses a virus to trick a person’s immune system into ignoring it.
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 report
1 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.