Enhancement of antibiotic effect via gold:silver-alloy nanoparticles
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A strategy for the development of novel antimicrobials is to combine the stability and pleiotropic effects of inorganic compounds with the specificity and efficiency of organic compounds, such as antibiotics. Here we report on the use of gold:silver-alloy (Au:Ag-alloy) nanoparticles, obtained via a single-step citrate co-reduction method, combined to conventional antibiotics to enhance their antimicrobial effect on bacteria. Addition of the alloy nanoparticles considerably decreased the dose of antibiotic necessary to show antimicrobial effect, both for bacterial cells growing in rich medium in suspension and for bacterial cells resting in a physiological buffer on a humid cellulose surface. The observed effect was more pronounced than the sum of the individual effects of the nanoparticles and antibiotic. We demonstrate the enhancement effect of Au:Ag-alloy nanoparticles with a size distribution of 32.5 ± 7.5 nm mean diameter on the antimicrobial effect of (i) kanamycin on Escherichia coli (Gram-negative bacterium), and (ii) a β-lactam antibiotic on both a sensitive and resistant strain of Staphylococcus aureus (Gram-positive bacterium). Together, these results may pave the way for the combined use of nanoparticle–antibiotic conjugates towards decreasing antibiotic resistance currently observed for certain bacteria and conventional antibiotics.
KeywordsGold:silver-alloy nanoparticles Antibiotic Antimicrobial Gram-negative bacteria E. coli S. aureus
We thank Fundação para a Ciência e Tecnologia (MCTES) for financial support: CIGMH, PTDC/CTM/NAN/109877/2009, PTDC/QUI–QUI/112597/2009 and Ciência 2007 Program. de Lencastre H is acknowledged for kindly providing S. aureus COL.
- Abubakar I, Irvine L, Aldus C, Wyatt G, Fordham R et al (2007) A systematic review of the clinical, public health and cost-effectiveness of rapid diagnostic tests for the detection and identification of bacterial intestinal pathogens in faeces and food. Health Technol Assess 11(36):1–216Google Scholar
- Ansari MA, Khan HM, Khan AA, Malik A, Sultan A, Shahid M, Shujatullah F, Azam A (2011) Evaluation of antibacterial activity of silver nanoparticles against MSSA and MSRA on isolates from skin infections. Biol Med 3:141–146Google Scholar
- Baptista PV, Doria G, Conde J (2011a) Alloy metal nanoparticles for multicolor cancer diagnostics. In: Colloidal quantum dots/nanocrystals for biomedical applications VI, proceedings of SPIE, vol 7909. SPIE, San FranciscoGoogle Scholar
- De Lencastre H, Wu SW, Pinho MG, Ludovice A, Filipe S et al (1999) Antibiotic resistance as a stress response: complete sequencing of a large number of chromosomal loci in Staphylococcus aureus strain COL that impact on the expression of resistance to methicillin. Microb Drug Resist 5:163–175CrossRefGoogle Scholar
- Doria G, Dias JT, Larguinho M, Pereira E, Franco R, Baptista P (2010a) AuAg-alloy-nanoprobes for specific nucleic acid detection. NSTI-Nanotechnol Proc 3:62–65 (ISBN 978-1-4398-3415-2)Google Scholar
- Jin T, Yiping H (2011) Antibacterial activities of magnesium oxide (MgO) nanoparticles against foodborne pathogens. J Nanopart Res. doi: 10.1007/s11051-011-0595-5
- Sabella S, Brunetti V, Vecchio G, Galeone A, Maiorano G, Cingolani R, Pomba PP (2011) Toxicity of citrate-capped AuNPs: Na in vitro and in vivo assessment. J Nanopart Res. doi: 10.1007/s11051-011-0590-x