Selenium Nanoparticles as Candidates for Antibacterial Substitutes and Supplements against Multidrug-Resistant Bacteria.

Sung-Hoon Lee,Soo-Kyung Jun,Hae-Hyoung Lee,Tae-Su Jang,Hae-Won Kim,Hee-Won Han,Jin-Hwan Kwak,Jung-Hwan Lee,Jonathan Campbell Knowles,Kapil D Patel

doi:10.3390/biom11071028

Abstract

In recent years, multidrug-resistant (MDR) bacteria have increased rapidly, representing a major threat to human health. This problem has created an urgent need to identify alternatives for the treatment of MDR bacteria. The aim of this study was to identify the antibacterial activity of selenium nanoparticles (SeNPs) and selenium nanowires (SeNWs) against MDR bacteria and assess the potential synergistic effects when combined with a conventional antibiotic (linezolid). SeNPs and SeNWs were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), zeta potential, and UV-visible analysis. The antibacterial effects of SeNPs and SeNWs were confirmed by the macro-dilution minimum inhibitory concentration (MIC) test. SeNPs showed MIC values against methicillin-sensitive S. aureus (MSSA), methicillin-resistant S. aureus (MRSA), vancomycin-resistant S. aureus (VRSA), and vancomycin-resistant enterococci (VRE) at concentrations of 20, 80, 320, and >320 μg/mL, respectively. On the other hand, SeNWs showed a MIC value of >320 μg/mL against all tested bacteria. Therefore, MSSA, MRSA, and VRSA were selected for the bacteria to be tested, and SeNPs were selected as the antimicrobial agent for the following experiments. In the time-kill assay, SeNPs at a concentration of 4X MIC (80 and 320 μg/mL) showed bactericidal effects against MSSA and MRSA, respectively. At a concentration of 2X MIC (40 and 160 μg/mL), SeNPs showed bacteriostatic effects against MSSA and bactericidal effects against MRSA, respectively. In the synergy test, SeNPs showed a synergistic effect with linezolid (LZD) through protein degradation against MSSA and MRSA. In conclusion, these results suggest that SeNPs can be candidates for antibacterial substitutes and supplements against MDR bacteria for topical use, such as dressings. However, for use in clinical situations, additional experiments such as toxicity and synergistic mechanism tests of SeNPs are needed.

Highlights

Since the discovery of penicillin, many antibiotics have been developed
The morphology and size, crystalline phase, chemical functional groups, and surface charge of selenium nanoparticles (SeNPs) and selenium nanowires (SeNWs) were characterized by transmission electron microscopy (TEM; JEOL-7100), X-ray diffraction (XRD; Rigaku, Tokyo, Japan), Fourier transform infrared spectroscopy (FTIR; 640-IR, Varian, VIC, Australia), zeta potentials
The morphology and shape of the sol-gel synthesized SeNPs and SeNWs were observed by HR-TEM (Figure 1A,B)

Summary

Introduction

Since the discovery of penicillin, many antibiotics have been developed. The number of bacteria that are resistant to antibiotics is increasing due to the misuse and abuse of antibiotics. Among these, when a bacterium is resistant to three or more antimicrobial classes, the bacterium is referred to as multidrug-resistant (MDR) [1]. MDR bacteria are a major problem that threatens human health [2,3]. MDR bacteria are the leading cause of nosocomial infections, and outcomes for patients infected with MDR bacteria tend to be worse than for patients infected with bacteria that are more sensitive to antibiotics [4,5,6]. There is an urgent need to identify new substances that can supplement conventional antibiotics or target MDR bacteria

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