TY - JOUR

T1 - Kin selection, quorum sensing and virulence in pathogenic bacteria

AU - Rumbaugh, Kendra P.

AU - Trivedi, Urvish

AU - Watters, Chase

AU - Burton-Chellew, Maxwell N

AU - Diggle, Stephen P

AU - West, Stuart A

PY - 2012

Y1 - 2012

N2 - Bacterial growth and virulence often depends upon the cooperative release of extracellular factors excreted in response to quorum sensing (QS). We carried out an in vivo selection experiment in mice to examine how QS evolves in response to variation in relatedness (strain diversity), and the consequences for virulence. We started our experiment with two bacterial strains: a wild-type that both produces and responds to QS signal molecules, and a lasR (signal-blind) mutant that does not release extracellular factors in response to signal. We found that: (i) QS leads to greater growth within hosts; (ii) high relatedness favours the QS wild-type; and (iii) low relatedness favours the lasR mutant. Relatedness matters in our experiment because, at relatively low relatedness, the lasR mutant is able to exploit the extracellular factors produced by the cells that respond to QS, and hence increase in frequency. Furthermore, our results suggest that because a higher relatedness favours cooperative QS, and hence leads to higher growth, this will also lead to a higher virulence, giving a relationship between relatedness and virulence that is in the opposite direction to that usually predicted by virulence theory.

AB - Bacterial growth and virulence often depends upon the cooperative release of extracellular factors excreted in response to quorum sensing (QS). We carried out an in vivo selection experiment in mice to examine how QS evolves in response to variation in relatedness (strain diversity), and the consequences for virulence. We started our experiment with two bacterial strains: a wild-type that both produces and responds to QS signal molecules, and a lasR (signal-blind) mutant that does not release extracellular factors in response to signal. We found that: (i) QS leads to greater growth within hosts; (ii) high relatedness favours the QS wild-type; and (iii) low relatedness favours the lasR mutant. Relatedness matters in our experiment because, at relatively low relatedness, the lasR mutant is able to exploit the extracellular factors produced by the cells that respond to QS, and hence increase in frequency. Furthermore, our results suggest that because a higher relatedness favours cooperative QS, and hence leads to higher growth, this will also lead to a higher virulence, giving a relationship between relatedness and virulence that is in the opposite direction to that usually predicted by virulence theory.

KW - Animals

KW - Bacterial Proteins/genetics

KW - Female

KW - Liver/microbiology

KW - Mice

KW - Pseudomonas Infections/microbiology

KW - Pseudomonas aeruginosa/genetics

KW - Quorum Sensing

KW - Selection, Genetic

KW - Skin/microbiology

KW - Trans-Activators/genetics

KW - Virulence

KW - Wounds and Injuries/microbiology

U2 - 10.1098/rspb.2012.0843

DO - 10.1098/rspb.2012.0843

M3 - Journal article

C2 - 22648154

VL - 279

SP - 3584

EP - 3588

JO - Proceedings of the Royal Society B: Biological Sciences

JF - Proceedings of the Royal Society B: Biological Sciences

SN - 0962-8452

IS - 1742

ER -