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Quorum-sensing and cheating in bacterial biofilms

Popat, Roman; Crusz, Shanika A.; Messina, Marco; Willams, Paul; West, Stuart A.; Diggle, Stephen P.


Roman Popat

Shanika A. Crusz

Marco Messina

Paul Willams

Stuart A. West

Stephen P. Diggle


The idea from human societies that self-interest can lead to a breakdown of cooperation at the group level
is sometimes termed the public goods dilemma. We tested this idea in the opportunistic bacterial pathogen,
Pseudomonas aeruginosa, by examining the influence of putative cheats that do not cooperate via
cell-to-cell signalling (quorum-sensing, QS).We found that: (i) QS cheating occurs in biofilm populations
owing to exploitation of QS-regulated public goods; (ii) the thickness and density of biofilms was reduced
by the presence of non-cooperative cheats; (iii) population growth was reduced by the presence of cheats,
and this reduction was greater in biofilms than in planktonic populations; (iv) the susceptibility of biofilms
to antibiotics was increased by the presence of cheats; and (v) coercing cooperator cells to increase their
level of cooperation decreases the extent to which the presence of cheats reduces population productivity.
Our results provide clear support that conflict over public goods reduces population fitness in bacterial
biofilms, and that this effect is greater than in planktonic populations. Finally, we discuss the clinical
implications that arise from altering the susceptibility to antibiotics.


Popat, R., Crusz, S. A., Messina, M., Willams, P., West, S. A., & Diggle, S. P. (2012). Quorum-sensing and cheating in bacterial biofilms. Proceedings of the Royal Society B: Biological Sciences, 279(1748), doi:10.1098/rspb.2012.1976

Journal Article Type Article
Publication Date Dec 1, 2012
Deposit Date Mar 28, 2014
Publicly Available Date Mar 28, 2014
Journal Proceedings of the Royal Society B: Biological Sciences
Print ISSN 0962-8452
Electronic ISSN 1471-2954
Publisher Royal Society, The
Peer Reviewed Peer Reviewed
Volume 279
Issue 1748
Public URL
Publisher URL


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