Phages and quorum sensing: findings to consider in phage therapy

Purpose This review aims to provide an overview of current knowledge on the involvement of QS in phage infection. The role of QS in bacterial defence against phages is emphasized, without overlooking the fact that QS can sometimes also promote phage infection. We also review the implications of QS in phage therapy and current perspectives. Methods For the bibliographic review, PubMed and Google Scholar were used to search for publications on “quorum-sensing” and “phage infection”. Results The relationships between bacteria and phages are extremely complicated and involve several mechanisms. Quorum sensing (QS) is a communication system involved in controlling bacterial fitness, both at population and individual levels. Phages (viruses that infect bacteria) play a major role in the natural regulation of bacterial populations. In order to protect themselves, bacteria have developed several defence mechanisms involving different levels of protection, such as prevention of phage entry and phage assembly, degradation of phage nucleic acids, and entrance in a dormant state (persistence). QS has recently been shown to affect some of these phage defence mechanisms. In this review, the main influence of QS in phage infection is discussed. Finally, some innovative treatment approaches, including using engineered phages harbouring T7aiiA QQ enzyme and QS inhibitors such as SsoPox-W2631 and penicillinic acid, are also considered. However, it is important to note that the use of QS-interfering molecules may also reduce the efficacy of phage therapy. Conclusion QS is an important mechanism that affects several bacterial metabolisms, particularly in phage defence. Despite the complex interaction between QS and phages, modifying QS has been found to enhance phage therapy.