Antibacterial contact-dependent proteins secreted by Gram-negative cystic fibrosis respiratory pathogens.

Cystic fibrosis (CF) is a genetic disease that affects almost 100 000 people worldwide. CF patients suffer from chronic bacterial airway infections that are often polymicrobial and are the leading cause of mortality. Interactions between pathogens modulate expression of genes responsible for virulence and antibiotic resistance. One of the ways bacteria can interact is through contact-dependent systems, which secrete antibacterial proteins (effectors) that confer advantages to cells that harbor them. Here, we highlight recent work that describes effectors used by Gram-negative CF pathogens to eliminate competitor bacteria. Understanding the mechanisms of secreted effectors may lead to novel insights into the ecology of bacteria that colonize respiratory tracts and could also pave the way for the design of new therapeutics.