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Updated: Jun 26, 2025
Anti-virulent Disruption of Pathogenic Biofilms using Engineered Quorum-quenching Lactonases
Published on: January 1, 2016
Miconazole and phenothiazine hinder the quorum sensing regulated virulence in Pseudomonas aeruginosa
Amany I Gad1, Amira M El-Ganiny2, Ahmed G Eissa3
1Microbiology and Immunology Department, Faculty of Pharmacy and Drug Technology, Egyptian Chinese University, Cairo, 11786, Egypt.
Abstract:
Antibiotic resistance is a major health problem worldwide. Pseudomonas aeruginosa is a Gram-negative pathogen with an arsenal of virulence factors and elevated antimicrobial resistance. It is a leading cause of nosocomial infections with high morbidity and mortality. The significant time and effort required to develop new antibiotics can be circumvented using alternative therapeutic strategies, including anti-virulence targets. This study aimed to investigate the anti-virulence activity of the FDA-approved drugs miconazole and phenothiazine against P. aeruginosa. The phenotypic effect of sub-inhibitory concentrations of miconazole and phenothiazine on biofilm, pyocyanin, protease, rhamnolipid and hemolysin activities in PAO1 strain was examined. qRT-PCR was used to assess the effect of drugs on quorum-sensing genes that regulate virulence. Further, the anti-virulence potential of miconazole and phenothiazine was evaluated in silico and in vivo. Miconazole showed significant inhibition of Pseudomonas virulence by reducing biofilm-formation approximately 45-48%, hemolytic-activity by 59%, pyocyanin-production by 47-49%, rhamnolipid-activity by approximately 42-47% and protease activity by 36-40%. While, phenothiazine showed lower anti-virulence activity, it inhibited biofilm (31-35%), pyocyanin (37-39%), protease (32-40%), rhamnolipid (35-40%) and hemolytic activity (47-56%). Similarly, there was significantly reduced expression of RhlR, PqsR, LasI and LasR following treatment with miconazole, but less so with phenothiazine. In-silico analysis revealed that miconazole had higher binding affinity than phenothiazine to LasR, RhlR, and PqsR QS-proteins. Furthermore, there was 100% survival in mice injected with PAO1 treated with miconazole. In conclusion, miconazole and phenothiazine are promising anti-virulence agents for P. aeruginosa.
Insights
Miconazole and phenothiazine show anti-virulence effects against Pseudomonas aeruginosa. Miconazole significantly reduced virulence factors and improved survival in mice, indicating its potential as an anti-virulence drug.
Area of Science:
- Microbiology
- Pharmacology
- Infectious Diseases
Background:
- Antibiotic resistance is a global health crisis, with Pseudomonas aeruginosa being a major multidrug-resistant pathogen.
- Developing new antibiotics is challenging; anti-virulence strategies offer an alternative therapeutic approach.
- Pseudomonas aeruginosa infections are associated with high morbidity and mortality, necessitating novel treatment strategies.
Purpose of the Study:
- To investigate the anti-virulence activity of FDA-approved drugs miconazole and phenothiazine against Pseudomonas aeruginosa.
- To evaluate the impact of these drugs on key virulence factors and quorum-sensing systems.
- To assess the in silico and in vivo efficacy of miconazole and phenothiazine as anti-virulence agents.
Main Methods:
- Phenotypic screening of sub-inhibitory drug concentrations on biofilm, pyocyanin, protease, rhamnolipid, and hemolysin production.
- Quantitative reverse transcription PCR (qRT-PCR) to analyze quorum-sensing gene expression.
- In silico molecular docking and in vivo mouse survival studies.
Main Results:
- Miconazole significantly inhibited biofilm formation (45-48%), hemolysin (59%), pyocyanin (47-49%), rhamnolipid (42-47%), and protease activity (36-40%).
- Phenothiazine demonstrated lower anti-virulence activity but still inhibited biofilm (31-35%) and other virulence factors.
- Miconazole treatment led to reduced expression of key quorum-sensing genes (RhlR, PqsR, LasI, LasR) and showed higher binding affinity to QS proteins in silico.
- Mice treated with miconazole exhibited 100% survival.
Conclusions:
- Miconazole and phenothiazine exhibit promising anti-virulence properties against Pseudomonas aeruginosa.
- Miconazole demonstrates significant efficacy in reducing virulence factor production and enhancing survival rates.
- These drugs represent potential alternative therapeutic agents for combating P. aeruginosa infections.
