Going beyond the Control of Quorum-Sensing to Combat Biofilm Infections

Abstract

Most bacteria attach to surfaces where they form a biofilm, cells embedded in a complex matrix of polymers. Cells in biofilms are much better protected against noxious agents than free-living cells. As a consequence it is very difficult to control pathogens with antibiotics in biofilm infections and novel targets are urgently needed. One approach aims at the communication between cells to form and to maintain a biofilm, a process called quorum-sensing. Water soluble small-sized molecules mediate this process and a number of antagonists of these compounds have been found. In this review natural compounds and synthetic drugs which do not interfere with the classical quorum-sensing compounds are discussed. For some of these compounds the targets are still not known, but others interfere with the formation of exopolysaccharides, virulence factors, or cell wall synthesis or they start an internal program of biofilm dispersal. Some of their targets are more conserved among pathogens than the receptors for quorum sensing autoinducers mediating quorum-sensing, enabling a broader application of the drug. The broad spectrum of mechanisms, the diversity of bioactive compounds, their activity against several targets, and the conservation of some targets among bacterial pathogens are promising aspects for several clinical applications of this type of biofilm-controlling compound in the future.

Microbial interactions: ecology in a molecular perspective

“…There are four strategies used to interfere with QS inhibition of: 1. signal generation; 2. signal dissemination, 3. Signal receptor and signaling response system 116, 117…”

Antiquorum sensing, antibiofilm formation and cytotoxicity activity of commonly used medicinal plants by inhabitants of Borabu sub-county, Nyamira County, Kenya

“…Existing studies suggest that targeting QS-regulated processes could be a new strategy for fighting bacterial infections associated to biofilm production and other virulence traits [ 18 , 19 ]. Nazzaro et al ., [ 19 ] further indicate that continued research is necessary to discover novel antimicrobial and antipathogenic agents focused on exploiting the fact that plants, surviving in an environment with a high bacterial density, may possess protective mechanisms for combating infections that could have therapeutic potential.…”

A new report of Nocardiopsis valliformis strain OT1 from alkaline Lonar crater of India and its use in synthesis of silver nanoparticles with special reference to evaluation of antibacterial activity and cytotoxicity

“…The biofilms protects the bacterial cells as compared to the free living cells. There are various reports on role of AgNPs against microbial biofilm [13, 17, 18]. …”