Bacteria and viruses cooperate to turn harmless infections to disease

"In the current study, the research team grew biofilms of pneumococci on top of human epithelial cells, where the bacteria normally grow. They then infected these bacteria with influenza A virus or exposed them to the conditions that typically accompany the flu, including increased temperature to mimic fever, increased concentrations of ATP (the energy molecule in cells), and the stress hormone norepinephrine, released during flu infection. All three stimuli triggered a sudden release and departure of bacteria from the biofilm in the nose into otherwise normally sterile organs, such as the middle ears and lungs or into the bloodstream. At the same time, the researchers found that the gene expression profile of the bacteria that had dispersed from the biofilms revealed far more virulence."