The Effect of Quorum-Sensing and Efflux Pumps Interactions in Pseudomonas aeruginosa Against Photooxidative Stress

Abstract

Quorum SensingCommunication between similar or different species occurs via various chemical signals produced and secreted by the bacteria. These signals can be population dependent (QS) or can be secreted during several proliferation stages (e.g., indole, which is secreted in the stationary phase by Escherichia coli). AbstractResistant infections essentially cause mortality in a burn unit. Several bacteria contribute to burn infections; among these, Pseudomonas aeruginosa majorly contributes to these infections revealing significant drug resistance. Similar to other bacteria, P. aeruginosa reveals various mechanisms to attain highest pathogenicity and resistance; among these, efflux pumps and quorum sensing are crucial. Quorum sensing enables effective communication between bacteria and synchronizes their gene expression resulting in optimum effect of the secreted proteins; alternatively, efflux pumps increase the bacterial resistance by pumping out the antimicrobial factors as well as the QS signals and precursors. Of recent, increasing episodes of drug resistance led to new findings and approaches for killing pathogenic bacteria without inducing the drug-resistant species. Photodynamic therapy (PDT), considered as an adjuvant and innovative method for conventional antibiotic therapy, is a photochemical reaction that includes visible light, oxygen, and a photosensitizer (PS). In this therapy, after exposure to visible light, the PS generates reactive oxygen species (ROS) that are bacteriostatic or bactericidal. Furthermore, this oxidative stress can disrupt the coordination of gene expression and alter the bacterial behavior. Considering the fact that the adaption and several gene expression patterns of microorganisms within the biofilm make them notably resistant to the recent antimicrobial treatments, this study aimed to emphasize the relationship between the efflux pump and QS under oxidative stress and their role in P. aeruginosa's reaction to PDT.

Acinetobacter baumannii Quorum sensing: A way to communicate and a target to eradicate

“…Several studies have shown that cell-to-cell communication and regulation of numerous virulence factors in bacteria are managed by QS systems [32][33][34][35][36]. In Staphylococcus aureus, the Agr system controls the production and dissemination of biofilm, consequently, inducing both acute and chronic biofilm-associated infections [36].…”

“…The LasI is one of the major mechanisms of pathogenicity and resistance of Pseudomonas aeruginosa. It regulates the biofilm formation, and virulence factors such as exotoxin A, elastase, pyocyanin, alkaline phosphatase, and rhamnolipid [35]. Similarly, Bacillus cereus virulence factors, such as phospholipases C, proteases and hemolysins, are controlled by the expression of QS system [38].…”

The MarR-Type Regulator PA3458 Is Involved in Osmoadaptation Control in Pseudomonas aeruginosa

“…P. aeruginosa has complex regulatory systems, which allow it to combat environmental stressors with the use of different mechanisms; e.g., in the presence of an antibiotic, cells could use efflux pumps [ 4 ] or form biofilm [ 5 ]. The multilevel regulatory network allows P. aeruginosa to modulate the metabolism to endure different stress conditions e.g., heat shock [ 6 ], the presence of antimicrobials [ 7 ], photooxidative [ 8 ], or osmotic stress [ 9 , 10 ].…”

Untitled

“…CS is a cell-tocell signaling mechanism that coordinates a range of behaviors at the population level [7]. CS is a mechanism by which the bacterium censes the microbial density present through the production of N-acyl homoserine lactone-like molecules, which function as autoinducers that bind with receptor proteins to form a complex that in turn favors the expression of genes that code for the production of more N-acyl-homoserine lactone synthase and the receptor itself, thus forming circuit mechanisms in las and rhl series, in which, consequently, the expression of virulence factors such as elastase, protease, pyocyanin will begin with which the bacteria will begin biofilm synthesis to contribute to its adhesion and infection progress [8]. Finally, there is a third molecule of CS, which is the so-called autoinducer-3 (AI-3), which involves signaling between taxonomic domains, that is, between bacteria and archaea (prokaryotic cells), and eukaryotes (organisms higher).…”