The efficacy of anti-virulence strategies in inhibiting quorum sensing system in P. aeruginosa
Pseudomonas aeruginosa is gram negative rod shaped bacteria, and a drug resistant bacterium, gives blue green pigment and fruity smell(1), also associated with numbers of hospital-acquired pneumonia infections, and accounts for some nosocomial urinary tract infections, and surgical wound infection cases, also of the infections in th e bloodstream, and is especially concerned with people with immunodeficiency where pneumonia and sever systemic infections can be caused. (2) the virulence factors of p.aerugenosa acting by density depending mechanism known as quorum sensing system.
with the significant increase of bacterial resistance, many studies have been done to improve strategies to overcome this resistance, many strategies such as down regulating the virulence factors and controlling the behavior of the bacteria. the virulence of P. aeruginosa relies on a density-dependent mechanism mediated by diffusible molecules called auto-inducers this system known as quorum sensing system. therefore This system constitutes an important target for anti-virulence therapies, during the colonization P. aeruginosa mutants (less virulence type) exploits the public goods from wild type P. aeruginosa ( more virulence type), what was done in this study is that the QS system inhibited in the wild type P. aeruginosa this inhibition decreases the selective advantages for P. aeruginosa mutants. this trail was done in randomized, placebo-controlled, double blind study, in which the anti-virulent drug was used is azithromycin macrolide antibiotic that has no bactericidal effect on P. aeruginosa, this drug used with intubated patients that infected with P. aeruginosa. With patients that did not receive azithromycin the levels of the less virulent type (lasR QS-mutants) have raised with time, but in presence of azithromycin the advantages of the less virulent type have decreased by inhibiting the growth of wild-type isolates