Synergistic Antimicrobial Metal Oxide-Doped Phosphate Glasses; a Potential Strategy to Reduce Antimicrobial Resistance and Host Cell Toxicity

• Published in: ACS biomaterials science & engineering Vol. 8; no. 3; pp. 1193 - 1199
• Main Authors: Raja, Farah N. S, Worthington, Tony, de Souza, Lucas P. L, Hanaei, Shirin B, Martin, Richard A
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 14.03.2022
• Subjects: Anti-Bacterial Agents - pharmacology; Anti-Infective Agents - pharmacology; Bacteria; Cobalt - pharmacology; Controlled Release and Delivery Systems; Copper - pharmacology; Drug Resistance, Bacterial; Escherichia coli; Phosphates - pharmacology; Staphylococcus aureus; Zinc Oxide; bioactive glasses; synergism; antimicrobial; antimicrobial resistance
• ISSN: 2373-9878; 2373-9878
• DOI: 10.1021/acsbiomaterials.1c00876

The emergence of antimicrobial resistant strains bacteria and a decline in the discovery of new antibiotics has led to the idea of combining various antimicrobials to treat resistant strains and/or polymicrobial infections. Metal oxide-doped glasses have been extensively investigated for their antimicrobial potential; however to date, most experiments have focused on single metal species in isolation. The present study investigates the antimicrobial potential of sodium calcium phosphates (P2O5)50(Na2O)20(CaO)30–X (MO) X , where M is cobalt, copper, or zinc as single species. In addition, this work studied the effect of co-doping glasses containing two different metal ions (Co + Cu, Co + Zn, and Cu + Zn). The antimicrobial efficacy of all glasses was tested against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacterial strains, as well as a fungal strain (Candida albicans). Minimum inhibitory and bactericidal concentrations and time kill/synergy assays were used to assess the antimicrobial activity. An enhanced antimicrobial effect, at 5 mg/mL concentration, was exhibited by cobalt, copper, and zinc oxide glasses alone and in combinations. A synergistic antimicrobial effect was observed by Cu + Co and Cu + Zn against E. coli and Cu + Zn against S. aureus.