Abstract
In response to the occurrence of antibiotic resistance, there has been rapid developments in the field of metal-based antimicrobials. Although it is largely assumed that metals provide broad-spectrum microbial efficacy, studies have shown that this is not always the case. Therefore, in this study, we compared the susceptibilities of 93 clinical isolates belonging to the species Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus against six metals, namely aluminum, copper, gallium, nickel, silver and zinc. To provide qualitative comparative information, the resulting zones of growth inhibition were compared to the minimal inhibitory concentrations of three indicator strains E. coli ATCC 25922, P. aeruginosa ATCC 27853 and S. aureus ATCC 25923. Here, we demonstrate that the metal efficacies were species- and isolate-specific. Only several isolates were either resistant or sensitive to all of the six metals, with great variability found between isolates. However, the greatest degree of similarity was found with the E. coli isolates. In contrast, the susceptibilities of the remaining two collections, S. aureus and P. aeruginosa, were more highly dispersed. Using this information, we have shown that metals are not equal in their efficacies. Hence, their use should be tailored against a particular microorganism and care should be taken to ensure the use of the correct concentration.
Highlights
In our modern era, the rising incidence of antibiotic resistance is a familiar concern that continues to provide challenges in infection control and disease prevention [1,2]
The efficacies of six metals, namely aluminum, copper, gallium, nickel, silver and zinc, were tested against 93 bacterial isolates using the disk diffusion assay, which allows for high-throughput susceptibility testing
In order to account for independent variables and provide reference, the zones of growth inhibition were normalized against the three pathogenic indicator strains, S. aureus ATCC
Summary
The rising incidence of antibiotic resistance is a familiar concern that continues to provide challenges in infection control and disease prevention [1,2]. Metals and metal-based antimicrobials are among these alternative agents that are presently being investigated (see review [6] for more information). As their name suggests, essential metals, such as zinc, copper and iron, are essential to the biochemistry of life. Advancements in the biomedical applications of metals primarily take the form of diagnostic procedures and the prevention of diseases following the discovery that metals can disrupt antibiotic resistant biofilms [11,12,13,14] and kill multidrug resistant bacteria [15,16,17,18] at low concentrations. Metals are being impregnated into textiles, including socks
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
