Competition in Biofilms between Cystic Fibrosis Isolates of Pseudomonas aeruginosa Is Shaped by R-Pyocins.
Oluyombo O, Penfold CN, Diggle SP
MBio. Jan 2019
COMMENT: A major clinical problem in individuals with cystic fibrosis (CF) is the chronic infection of the lungs caused by Pseudomonas aeruginosa. In this interesting paper the authors study the role that the S- and R-pyocins play in the competition between P. aeruginosa strains.
Here we investigate whether R-pyocins are important factors in competitive interactions between P. aeruginosa strains taken directly from CF lungs from different patients.
(...) individual P. aeruginosa strains taken from different CF patients produced only one R-pyocin type, whereas the number of S-pyocin types produced by any one strain varied.
R-pyocins were crucial for strain dominance during competition assays in planktonic cultures and within biofilms, as well as where variations in both R and S subtypes occurred in the competing strains.
Exposure of live cells, planktonic or biofilm, to extracted R-pyocins (...) results in killing in the absence of a live competing strain.
Our work provides support for a role played by R-pyocins in the competition between P. aeruginosa strains and helps explain why certain strains and lineages of P. aeruginosa dominate and displace others during CF infection.
R-pyocins could be a useful alternative for antibiotics or phage therapy for infections involving biofilms or for biofilms growing on medical devices such as catheters.