Effect of chitosan nanoparticles on quorum sensing-controlled virulence factors and expression of <i>LasI</i> and <i>RhlI</i> genes among <i>Pseudomonas aeruginosa</i> clinical isolates

Abstract

&lt;abstract&gt; &lt;p&gt;Antibiotic-resistant strains of &lt;italic&gt;Pseudomonas aeruginosa (P. aeruginosa&lt;/italic&gt;) pose a major threat for healthcare-associated and community-acquired infections. &lt;italic&gt;P. aeruginosa&lt;/italic&gt; is recognized as an opportunistic pathogen using quorum sensing (QS) system to regulate the expression of virulence factors and biofilm development. Thus, meddling with the QS system would give alternate methods of controlling the pathogenicity. This study aimed to assess the inhibitory impact of chitosan nanoparticles (CS-NPs) on &lt;italic&gt;P. aeruginosa&lt;/italic&gt; virulence factors regulated by QS (e.g., motility and biofilm formation) and &lt;italic&gt;LasI&lt;/italic&gt; and &lt;italic&gt;RhlI&lt;/italic&gt; gene expression. Minimum inhibitory concentration (MIC) of CS-NPs against 30 isolates of &lt;italic&gt;P. aeruginosa&lt;/italic&gt; was determined. The CS-NPs at sub-MIC were utilized to assess their inhibitory effect on motility, biofilm formation, and the expression levels of &lt;italic&gt;LasI&lt;/italic&gt; and &lt;italic&gt;RhlI&lt;/italic&gt; genes. CS-NPs remarkably inhibited the tested virulence factors as compared to the controls grown without the nanoparticles. The mean (±SD) diameter of swimming motility was decreased from 3.93 (±1.5) to 1.63 (±1.02) cm, and the mean of the swarming motility was reduced from 3.5 (±1.6) to 1.9 (±1.07) cm. All isolates became non-biofilm producers, and the mean percentage rate of biofilm inhibition was 84.95% (±6.18). Quantitative real-time PCR affirmed the opposition of QS activity by lowering the expression levels of &lt;italic&gt;LasI&lt;/italic&gt; and &lt;italic&gt;RhlI&lt;/italic&gt; genes; the expression level was decreased by 90- and 100-folds, respectively. In conclusion, the application of CS-NPs reduces the virulence factors significantly at both genotypic and phenotypic levels. These promising results can breathe hope in the fight against resistant &lt;italic&gt;P. aeruginosa&lt;/italic&gt; by repressing its QS-regulated virulence factors.&lt;/p&gt; &lt;/abstract&gt;

Nanomaterials Regulate Bacterial Quorum Sensing: Applications, Mechanisms, and Optimization Strategies

“…[ 244 ] Besides the lack of in‐vivo studies, most studies have only confirmed at the phenomenological level that nanomaterials have QS regulatory effects (such as reducing the production of QS‐regulated virulence factors, inhibiting swarming and swimming motility, and disrupting biofilm formation), while research on the specific molecular mechanisms by which nanomaterials regulate bacterial QS is relatively limited. [ 245 ] The possible reason is that existing mechanistic research mostly relies on computerized molecular docking techniques to simply predict whether there is a direct interaction between nanomaterials and known QS system components. [ 150 , 246 ] The introduction of more advanced analytical tools in the future, such as high‐resolution single‐atom imaging techniques, is expected to break through this limitation.…”

Exploring the antimicrobial potential of chitosan nanoparticles: synthesis, characterization and impact on Pseudomonas aeruginosa virulence factors

“…This can lead to the formation of an impermeable layer of CS-NPs around the bacterium, thereby preventing transport through the outer membrane of G-bacteria. 10 Additionally, the nanoscale dimensions may promote biocompatibility and reduce unwanted interactions with the immune system. 11 As a result, we have embarked on an investigation into the antimicrobial effects of CS-NPs using a model microorganism for biofilm formation, Pseudomonas aeruginosa (PA).…”