Ruthenium Complexes with 2-Pyridin-2-yl-1H-benzimidazole as Potential Antimicrobial Agents: Correlation between Chemical Properties and Anti-Biofilm Effects.

Agnieszka Jabłońska-Wawrzycka,Katarzyna Gałczyńska,Magdalena Dańczuk,Grzegorz Czerwonka,Marcin Drabik,Patrycja Rogala

doi:10.3390/ijms221810113

Agnieszka Jabłońska-Wawrzycka, Katarzyna Gałczyńska + Show 4 more

Open Access

https://doi.org/10.3390/ijms221810113

Copy DOI

Abstract

Antimicrobial resistance is a growing public health concern that requires urgent action. Biofilm-associated resistance to antimicrobials begins at the attachment phase and increases as the biofilms maturate. Hence, interrupting the initial binding process of bacteria to surfaces is essential to effectively prevent biofilm-associated problems. Herein, we have evaluated the antibacterial and anti-biofilm activities of three ruthenium complexes in different oxidation states with 2-pyridin-2-yl-1H-benzimidazole (L1 = 2,2′-PyBIm): [(η6-p-cymene)RuIIClL1]PF6 (Ru(II) complex), mer-[RuIIICl3(CH3CN)L1]·L1·3H2O (Ru(III) complex), (H2L1)2[RuIIICl4(CH3CN)2]2[RuIVCl4(CH3CN)2]·2Cl·6H2O (Ru(III/IV) complex). The biological activity of the compounds was screened against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa strains. The results indicated that the anti-biofilm activity of the Ru complexes at concentration of 1 mM was better than that of the ligand alone against the P. aeruginosa PAO1. It means that ligand, in combination with ruthenium ion, shows a synergistic effect. The effect of the Ru complexes on cell surface properties was determined by the contact angle and zeta potential values. The electric and physical properties of the microbial surface are useful tools for the examined aggregation phenomenon and disruption of the adhesion. Considering that intermolecular interactions are important and largely define the functions of compounds, we examined interactions in the crystals of the Ru complexes using the Hirshfeld surface analysis.

Highlights

Microbial resistance to antibiotics is increasingly becoming a global public health problem that threatens the successful treatment of infectious diseases
We investigated the impact of the Ru complexes on the parameters of bacterial surface, such as potential (ζ) and the contact angle
The coordination compounds were synthesized following the procedure described in the literature [31,32], using the mother solution (0.1 M RuCl3) or the Ru(II) precursor ([(η6-p-cymene)Ru(μ-Cl)Cl]2), the N,N-donor ligand (2,2 -PyBIm, L1), and proper solvents as starting materials

Summary

Introduction

Microbial resistance to antibiotics is increasingly becoming a global public health problem that threatens the successful treatment of infectious diseases. The strong resistance of bacterial biofilms is related to both bacteria aggregation in multicellular communities and the structure of extracellular polymeric substances (EPSs) matrix [6]. Once biofilms form, these features influence the enhancement of genetic exchange, the concentration of quorum sensing (QS) signal molecules, the development of persisters, and the chelation of antimicrobials. To prevent biofilm formation, the attachment of planktonic cells to surfaces or the maturation of early microcolonies to fully structured biofilms must be disrupted It can be achieved by modifying the surface to which microbes attach or by treating microbial cells with chemical compounds to block or weaken their attachments to the surface. We focused on chemical treatments for the inhibition of biofilm formation

Methods

Results

Conclusion