Nitroxoline: a broad-spectrum biofilm-eradicating agent against pathogenic bacteria

Area of Science:

• Microbiology
• Infectious Diseases
• Drug Discovery

Background:

• Bacterial biofilms are prevalent in chronic infections (approx. 80%) and exhibit tolerance to conventional antibiotics.
• Current therapeutic strategies lack agents capable of eradicating established biofilms.
• Drug-resistant pathogens like Staphylococcus aureus and Acinetobacter baumannii pose significant clinical challenges.

Purpose of the Study:

• To investigate the biofilm-eradicating potential of nitroxoline against major human pathogens.
• To evaluate nitroxoline's efficacy in both in vitro and ex vivo models.
• To assess nitroxoline's activity against antibiotic-tolerant persister cells.

Main Methods:

• Minimum Biofilm Eradication Concentration (MBEC) assays were performed against Acinetobacter baumannii.
• Ex vivo porcine skin models were utilized to assess biofilm eradication.
• Stationary phase cultures of methicillin-resistant Staphylococcus aureus (MRSA) were used to test nitroxoline against persister cells.

Main Results:

• Nitroxoline demonstrated broad-spectrum biofilm eradication activity against key human pathogens.
• In vitro testing showed an MBEC of 46.9 µM against A. baumannii.
• Ex vivo models achieved a 2-3 log reduction in viable biofilm cells.
• Nitroxoline eradicated MRSA persister cells, while vancomycin and daptomycin were ineffective.

Conclusions:

• Nitroxoline exhibits significant potential as a therapeutic agent for biofilm-associated infections.
• The drug's ability to eradicate biofilms and persister cells warrants further clinical investigation.
• Nitroxoline-based therapies could offer a novel solution for treating infections caused by drug-resistant bacteria.