Data from: Quorum sensing and cheating in bacterial biofilms

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.人类社会中关于个体自利可引发群体层面合作崩塌的观点，有时被称为公共物品困境（public goods dilemma）。我们以机会致病性细菌铜绿假单胞菌（Pseudomonas aeruginosa）为研究对象，通过探究不依赖细胞间信号传导（群体感应，quorum-sensing, QS）进行合作的潜在欺骗菌株的影响，对该观点进行了验证。我们发现：(i) 群体感应欺骗现象存在于生物膜种群中，源于对群体感应调控的公共物品的利用；(ii) 非合作欺骗菌株的存在会降低生物膜的厚度与密度；(iii) 欺骗菌株的存在会抑制种群增长，且该抑制效应在生物膜种群中较浮游种群更为显著；(iv) 欺骗菌株的存在会提升生物膜对抗生素的敏感性；(v) 强制合作细胞提升合作水平，可削弱欺骗菌株存在对种群生产力的抑制程度。本研究结果明确证实，公共物品冲突会降低细菌生物膜的种群适合度，且该效应相较于浮游种群更为突出。最后，我们探讨了改变抗生素敏感性所带来的临床意义。