Quorum Quenching Enzymes: A Potent Alternative to Conventional Antibiotics

Abstract

AbstractAntibiotic resistance has emerged as a serious problem in the twenty-first century. The inefficacy of conventional antibiotics for the treatment of bacterial infections has been a major concern in recent years. This led to a situation where most of the diseases caused by bacteria will become incurable, thus necessitating the development of innovative alternative antibacterials. Promisingly, the study of bacterial intercellular communication and its relation to pathogenesis has provided a direction to develop a novel strategy to treat bacteria-mediated infections, known as anti-virulence therapy. The intercellular communication between bacterial cells using diffusible signalling molecules (autoinducers) is known as quorum sensing (QS). Currently, quorum sensing inhibitors (QSIs), which interfere with bacterial pathogenicity and/or cell-to-cell signalling pathways, have been selected as the promising alternatives to conventional antibiotics for controlling infection without any selective pressure among bacterial pathogens. Quorum quenching (QQ) is the silencing of quorum sensing signals by enzymatic degradation or modification. Quorum quenching enzymes are common in bacteria and have also been discovered in eukaryotes. Lactonases and acylases that hydrolyze N-acyl homoserine lactone (AHL) signalling molecules have received the greatest attention as QQ enzymes. However, oxidoreductases are reported to target AHLs or 2-alkyl-4(1H)-quinolone. So far, the research on quorum quenching enzymes, which interfere with the production of virulence factors, strengthens the submission for the development of potential antibacterial strategies alternatives to traditional antibiotics. In this chapter, the basic mechanism of QS in both Gram-positive and Gram-negative bacteria, the promising anti-virulence strategies and quorum quenching enzymes for the future treatment of bacterial infections has been discussed. Further, modification of QQ enzymes to enhance their therapeutic efficiency and medical applications have also been discussed.KeywordsAntibacterialBacterial infectionsAntibiotic resistanceAutoinducersQuorum sensing inhibitorsQuorum quenchingQuorum quenching enzymesBacterial virulenceLactonasesAcylasesHomoserine lactonesAutoinducing peptidesAutoinducer-2