Prevention of biofilm formation by quorum quenching

Abstract

Quorum sensing (QS) is a mechanism that enables microbial communication. It is based on the constant secretion of signaling molecules to the environment. The main role of QS is the regulation of vital processes in the cell such as virulence factor production or biofilm formation. Due to still growing bacterial resistance to antibiotics that have been overused, it is necessary to search for alternative antimicrobial therapies. One of them is quorum quenching (QQ) that disrupts microbial communication. QQ-driving molecules can decrease or even completely inhibit the production of virulence factors (including biofilm formation). There are few QQ strategies that comprise the use of the structural analogues of QS receptor autoinductors (AI). They may be found in nature or be designed and synthesized via chemical engineering. Many of the characterized QQ molecules are enzymes with the ability to degrade signaling molecules. They can also impede cellular signaling cascades. There are different techniques used for testing QS/QQ, including chromatography-mass spectroscopy, bioluminescence, chemiluminescence, fluorescence, electrochemistry, and colorimetry. They all enable qualitative and quantitative measurements of QS/QQ molecules. This article gathers the information about the mechanisms of QS and QQ, and their effect on microbial biofilm formation. Basic methods used to study QS/QQ, as well as the medical and biotechnological applications of QQ, are also described. Basis research methods are also described as well as medical and biotechnological application.

Bacteria associated with marine macroorganisms as potential source of quorum‐sensing antagonists

“…A similar concept was proposed in the past where the quorum-quenching bacteria were isolated by co-streaking with the biosensor strain and AHL donor strain [16]. Other approaches reported for the screening of QSI-producing bacteria include residual AHL measurement, plate inhibition assay, and minimum medium assay used to detect AHL usage by bacteria [17][18][19]. However, these methods are biased toward the detection of AHL-degrading bacteria.…”

Combating Implant Infections: Shifting Focus from Bacteria to Host

“…These AIPs are synthesized in the form of prepeptides, secreted via a specialized transport system, and are sensed by proteins with kinase activity, leading to phosphorylation of a response regulator protein. [295,296] Once a threshold of AHLs or AIPs are reached, the transcription of QS-regulated genes will provide the bacterial population with enhanced protection against the host's defense mechanisms. [293] QS is closely associated with resistance to antibiotic and host-mediated killing; [297] hence the dysregulation of the normal QS systems is an important target in the development of biomaterials that can better control infection.…”

“…using TrAIP-II), [294,303] and 4) inactivation of autoinducers (e.g., using enzymes degrading AHL molecules. [295,296] Orthopedic implants most often fail due to Staphylococcal infections [3] with the accessory gene regulator (agr) QS system playing a key regulatory role in their pathogenic phenotype. [300] As a result, several anti-Agr compounds have been developed that could potentially be harnessed to render biomaterials with anti-infective properties.…”

“…[295] Although several enzymes with such capacity have been identified, they only target AHL molecules secreted by Gram-negative bacteria and are therefore still of limited use in context of IAI. [295,296]…”

Green tea (Camellia sinensis) extract inhibits biofilm formation in acyl homoserine lactone-producing, antibiotic-resistant Morganella morganii isolated from Pasig River, Philippines

“…Since biofilm formation is controlled by quorum sensing, pathogenic and opportunistic microorganisms are able to survive and adapt in different environments by regulating their genes which are responsible for virulence, biofilm production and genetic transfer [ 26 ]. Inhibitors of both QS and biofilm formation are currently being studied as potential alternatives to antibiotics because of their low to zero possibility of developing resistance [ 10 ].…”