Silver Antibacterial Synergism Activities with Eight Other Metal(loid)-Based Antimicrobials against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus

Abstract

The present study surveys potential antibacterial synergism effects of silver nitrate with eight other metal or metalloid-based antimicrobials (MBAs), including silver nitrate, copper (II) sulfate, gallium (III) nitrate, nickel sulfate, hydrogen tetrachloroaurate (III) trihydrate (gold), aluminum sulfate, sodium selenite, potassium tellurite, and zinc sulfate. Bacteriostatic and bactericidal susceptibility testing explored antibacterial synergism potency of 5760 combinations of MBAs against three bacteria (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus) in three different media. Silver nitrate in combination with potassium tellurite, zinc sulfate, and tetrachloroaurate trihydrate had remarkable bactericidal and bacteriostatic synergism effects. Synergism properties of MBAs decreased effective antibacterial concentrations remarkably and bacterial cell count decreased by 8.72 log10 colony-forming units (CFU)/mL in E. coli, 9.8 log10 CFU/mL in S. aureus, and 12.3 log10 CFU/mL in P. aeruginosa, compared to each MBA alone. Furthermore, most of the MBA combinations inhibited the recovery of bacteria; for instance, the combination of silver nitrate–tetrachloroaurate against P. aeruginosa inhibited the recovery of bacteria, while three-fold higher concentration of silver nitrate and two-fold higher concentration of tetrachloroaurate were required for inhibition of recovery when used individually. Overall, higher synergism was typically obtained in simulated wound fluid (SWF) rather than laboratory media. Unexpectedly, the combination of A silver nitrate–potassium tellurite had antagonistic bacteriostatic effects in Luria broth (LB) media for all three strains, while the combination of silver nitrate–potassium tellurite had the highest bacteriostatic and bactericidal synergism in SWF. Here, we identify the most effective antibacterial MBAs formulated against each of the Gram-positive and Gram-negative pathogen indicator strains.

Antimicrobial activity of supramolecular salts of gallium(III) and proflavine and the intriguing case of a trioxalate complex

“…As found previously 32 – 34 , differences in antimicrobial susceptibility towards metal-based antimicrobials is seen between the three different strains. The strains chosen for evaluation include a Gram-negative enteric pathogen Escherichia coli, the opportunistic pathogen and ubiquitous soil organism Pseudomonas aeruginosa and the Gram-positive opportunistic pathogen Staphylococcus aureus .…”

Fabrication and Application of Photocatalytic Composites and Water Treatment Facility Based on 3D Printing Technology

“…This sterilization mechanism has been reported by Fonseca et al [ 41 ], and the sterilization effect of our composites is better than theirs. It can also be seen in Figure 13 that the bactericidal effect of TiO 2 /PLA composites is weaker than that of the coating on this basis, since the silver particles on the surface of the coating can be tightly combined with the sulfhydryl group of the enzyme protein in the bacteria to make the protein coagulate, destroying the activity of cell synthase, and causing the cell to lose the ability to divide and die [ 42 , 43 ]. Another important reason is that the TiO 2 content of the coating is more than that of the composites under the same surface area.…”

Advancement of Gallium and Gallium-Based Compounds as Antimicrobial Agents

“…Recently, the combination of multiple antibacterial agents to achieve enhanced antibacterial effects has become a research hotspot (Pormohammad & Turner, 2020). With the excessive use of antibiotics and metal ions, bacteria gradually acquire drug resistance through horizontal gene transmission or gene mutation (Sutterlin et al, 2017).…”

“…Several studies investigated the antimicrobial synergies between different metal ions, and fractional inhibitory concentration and fractional bactericidal concentration assays were used to evaluate synergistic intensity (Yoon et al, 2006;Aziz, 2019;Vaidya et al, 2019;Pormohammad & Turner, 2020). The results showed that silver ions, zinc ions, Cd, Se, and Ga had good synergistic effects.…”