353
14.2 Quorum Quenching
The term “Quorum Quenching” was coined to describe all the processes that interfere with quorum sensing. Quorum quenching has been recommended as a promising innovative tool for the development of novel therapeutics to control microbial
infections. The application of quorum quenching compounds to fight bacterial
pathogenicity is particularly alluring with the emergence of multidrug resistant bacteria (Adak et al. 2011). One bacterial species may have advantage over the other in
its ability to disrupt quorum sensing; this is mostly found in niches where the bacterial populations compete for limited resources. Similarly, the host’s ability to step-in
bacterial cell-cell communication may play an essential role in preventing colonization by pathogenic bacteria that use quorum sensing to coordinate virulence. Thus,
quorum quenching has evolved as a mechanism to interfere with bacterial cell-cell
communication (Waters and Bassler 2005; Adak et al. 2011).
Some of the well-known examples of quorum quenching compounds include
acylases/lactones that are involved in the degradation of N-(3-oxoctanoyl)homoserine lactone (HSL) autoinducers, synthase inhibitors like analogues of
anthranilic acid (LaSarre and Federle 2013; Defoirdt et al. 2013) acting as quorum
quenchers and obstructing the synthesis of quinolone signals (Lesic et al. 2007;
García-Contreras et al. 2013). Some receptor inhibitors also act as quorum quenchers, such as brominated furanones (Defoirdt et al. 2007; García-Contreras et al.
2013). In addition to this some of the antibiotics like azithromycin, ceftazidime, and
ciprofloxacin in low concentrations have been found to inhibit quorum sensing in
Pseudomonas aeruginosa (Skindersoe et al. 2008; García-Contreras et al. 2013).
Niclosamide, the antihelminthic drug is also a quorum quenching compound which
reduces biofilm formation, surface motility, and the production of the secreted virulence factors like elastase, pyocyanin, and rhamnolipids (Imperi et al. 2013).
Stenotrophomonas maltophilia produces cis-9-octadecenoic acid, which is a quorum quenching compound and it involves in the reduction of violacein production
by Chromobacterium violaceum and also affects the biofilm formation in P. aeruginosa (Singh et al. 2013; García-Contreras et al. 2013). Quorum sensing dependent
characters, such as elastase activity, protease activity, and the production of pyocyanin, was inhibited by a cyclic dipeptide 2,5-piperazinedione; which act as a quorum
quencher (Musthafa et al. 2012; García-Contreras et al. 2013). Some of the quorum
quenching bacteria was isolated from healthy coral species (Golberg et al. 2013;
García-Contreras et al. 2013). The presence of anti-QS compounds in corals may
possibly provide the clues about the competitive interactions of coral-associated
bacteria. Quorum quenching compounds are secreted from the dominant communities to minify undesirable marine biofouling.
14 Quorum Quenching Compounds from Natural Sources
14.2 Quorum Quenching
The term “Quorum Quenching” was coined to describe all the processes that interfere with quorum sensing. Quorum quenching has been recommended as a promising innovative tool for the development of novel therapeutics to control microbial
infections. The application of quorum quenching compounds to fight bacterial
pathogenicity is particularly alluring with the emergence of multidrug resistant bacteria (Adak et al. 2011). One bacterial species may have advantage over the other in
its ability to disrupt quorum sensing; this is mostly found in niches where the bacterial populations compete for limited resources. Similarly, the host’s ability to step-in
bacterial cell-cell communication may play an essential role in preventing colonization by pathogenic bacteria that use quorum sensing to coordinate virulence. Thus,
quorum quenching has evolved as a mechanism to interfere with bacterial cell-cell
communication (Waters and Bassler 2005; Adak et al. 2011).
Some of the well-known examples of quorum quenching compounds include
acylases/lactones that are involved in the degradation of N-(3-oxoctanoyl)homoserine lactone (HSL) autoinducers, synthase inhibitors like analogues of
anthranilic acid (LaSarre and Federle 2013; Defoirdt et al. 2013) acting as quorum
quenchers and obstructing the synthesis of quinolone signals (Lesic et al. 2007;
García-Contreras et al. 2013). Some receptor inhibitors also act as quorum quenchers, such as brominated furanones (Defoirdt et al. 2007; García-Contreras et al.
2013). In addition to this some of the antibiotics like azithromycin, ceftazidime, and
ciprofloxacin in low concentrations have been found to inhibit quorum sensing in
Pseudomonas aeruginosa (Skindersoe et al. 2008; García-Contreras et al. 2013).
Niclosamide, the antihelminthic drug is also a quorum quenching compound which
reduces biofilm formation, surface motility, and the production of the secreted virulence factors like elastase, pyocyanin, and rhamnolipids (Imperi et al. 2013).
Stenotrophomonas maltophilia produces cis-9-octadecenoic acid, which is a quorum quenching compound and it involves in the reduction of violacein production
by Chromobacterium violaceum and also affects the biofilm formation in P. aeruginosa (Singh et al. 2013; García-Contreras et al. 2013). Quorum sensing dependent
characters, such as elastase activity, protease activity, and the production of pyocyanin, was inhibited by a cyclic dipeptide 2,5-piperazinedione; which act as a quorum
quencher (Musthafa et al. 2012; García-Contreras et al. 2013). Some of the quorum
quenching bacteria was isolated from healthy coral species (Golberg et al. 2013;
García-Contreras et al. 2013). The presence of anti-QS compounds in corals may
possibly provide the clues about the competitive interactions of coral-associated
bacteria. Quorum quenching compounds are secreted from the dominant communities to minify undesirable marine biofouling.
14 Quorum Quenching Compounds from Natural Sources