In Vitro and In Vivo Studies on a Mononuclear Ruthenium Complex Reveals It is a Highly Effective, Fast-Acting,...

Area of Science:

• Inorganic Chemistry
• Antimicrobial Research
• Structural Biology

Background:

• Ruthenium(II) complexes are explored for their antimicrobial properties.
• Bacterial infections, including catheter-associated urinary tract infections (CAUTI) and Methicillin-resistant Staphylococcus aureus (MRSA), pose significant clinical challenges.
• Novel antimicrobial agents targeting bacterial DNA are needed.

Purpose of the Study:

• To present the crystal structure of an antimicrobial Ru(II) complex.
• To evaluate the antimicrobial activity of the Ru(II) complex against clinical bacterial isolates under various conditions.
• To assess the potential of the Ru(II) complex in combination therapies and in a model organism.

Main Methods:

• X-ray crystallography was used to determine the crystal structure.
• Antimicrobial activity was tested against Gram-negative bacteria (causing CAUTI) and Staphylococcus aureus (including MRSA) in simulated urine and plasma media.
• Activity was assessed under different growth phases and pH conditions.
• Combinatorial studies with conventional antibiotics and a dinuclear Ru(II) complex were performed.
• Efficacy was evaluated in the Galleria Mellonella infection model.

Main Results:

• The crystal structure of the antimicrobial Ru(II) complex was determined.
• The complex demonstrated potent antimicrobial activity against Gram-negative bacteria and MRSA strains, maintaining efficacy in simulated urine and plasma, and across different pH and growth conditions.
• Combinatorial treatments showed additive antibacterial effects, approaching synergy in one instance.
• A single dose of the complex successfully cleared multidrug-resistant Acinetobacter baumannii in the Galleria Mellonella model without host toxicity.

Conclusions:

• The Ru(II) complex exhibits broad-spectrum antimicrobial activity and stability under relevant clinical conditions.
• The compound retains potent activity against MRSA and demonstrates promising additive effects with existing antibiotics.
• The Ru(II) complex shows potential as a novel therapeutic agent for treating challenging bacterial infections, including those caused by multidrug-resistant pathogens.