Frontal attack or stealth? How subverting the immune system shapes the arms race between bacteria and hosts
Why is it that Mycobacterium tuberculosis can cause tuberculosis with as little as 10 cells, whereas Vibrio cholerae requires the host to ingest up to tens of millions of cells to cause cholera? This is the question that two research teams, from the Pasteur Institute, in France, and the Instituto Gulbenkian de Ciencia and the University of Lisbon, in Portugal, answer in the latest issue of the journal PLoS Pathogens. The researchers show that bacteria that are able to invade and/or destroy cells of the host's immune system have higher infectivity, whereas those that are more motile, multiply faster and communicate with each other are less infectious, that is, it takes more bacterial cells to trigger an infection. These findings help understand the patterns that shape infectivity of bacteria, and contribute to more accurate predictions of how emerging pathogens may evolve, with implications for public health.