There are alarming reports of growing microbial resistance to all classes of antimicrobial agents used against different infections. Also the existing classes of anticancer drugs used against different tumours warrant the urgent search for more effective alternative agents for treatment. Broad-spectrum bioactivities of silver nanoparticles indicate their potential to solve many microbial resistance problems up to a certain extent. The antibacterial, antifungal, antiviral, antiprotozoal, acaricidal, larvicidal, lousicidal and anticancer activities of silver nanoparticles have recently attracted the attention of scientists all over the world. The aim of the present review is to discuss broad-spectrum multifunctional activities of silver nanoparticles and stress their therapeutic potential as smart nanomedicine. Much emphasis has been dedicated to the antimicrobial and anticancer potential of silver nanoparticles showing their promising characteristics for treatment, prophylaxis and control of infections, as well as for diagnosis and treatment of different cancer types.

The worldwide escalation of bacterial resistance to conventional medical antibiotics is a serious concern for modern medicine. High prevalence of multidrug-resistant bacteria among bacteria-based infections decreases effectiveness of current treatments and causes thousands of deaths. New improvements in present methods and novel strategies are urgently needed to cope with this problem. Owing to their antibacterial activities, metallic nanoparticles represent an effective solution for overcoming bacterial resistance. However, metallic nanoparticles are toxic, which causes restrictions in their use. Recent studies have shown that combining nanoparticles with antibiotics not only reduces the toxicity of both agents towards human cells by decreasing the requirement for high dosages but also enhances their bactericidal properties. Combining antibiotics with nanoparticles also restores their ability to destroy bacteria that have acquired resistance to them. Furthermore, nanoparticles tagged with antibiotics have been shown to increase the concentration of antibiotics at the site of bacterium-antibiotic interaction, and to facilitate binding of antibiotics to bacteria. Likewise, combining nanoparticles with antimicrobial peptides and essential oils generates genuine synergy against bacterial resistance. In this article, we aim to summarize recent studies on interactions between nanoparticles and antibiotics, as well as other antibacterial agents to formulate new prospects for future studies. Based on the promising data that demonstrated the synergistic effects of antimicrobial agents with nanoparticles, we believe that this combination is a potential candidate for more research into treatments for antibiotic-resistant bacteria.

Antibiotic resistance is documented to be a serious problem that affects the choice of appropriate antibiotic therapy and increases the probability of unfavorable infection outcome. One of the proposed methods to cope with multidrug-resistant (MDR) bacteria is the use of alternative antibacterial treatments, which include natural antimicrobial substances such as plant essential oils (EOs). The aim of the present article is to review published studies on the activity of EOs and their constituents against MDR bacteria and to formulate perspectives for the future. In general, published studies indicate that EOs can be used as effective antiseptics against many species, including MDR bacteria, such as methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, resistant isolates of Pseudomonas aeruginosa, Klebsiella pneumoniae and others; certain EOs may potentiate the effectiveness of antibiotics against MDR bacteria; EOs can be synergistic with bacteriophages; and polymeric nanoparticles can be used for delivery of EOs and enhancement of their activity at the site of infection.

Nanotechnology is an emerging cutting-edge technology, which involves interdisciplinary subjects, such as physics, chemistry, biology, material science and medicine. Different methods for the synthesis of nanoparticles have been discussed here. Although physical and chemical methods have been successfully used to synthesize nanoparticles, the use of hazardous chemicals and synthesis at high temperature is a matter of concern. Hence, there is a necessity to develop eco-friendly techniques for the synthesis of nanoparticles. Biosynthesis of nanoparticles by fungi, bacteria, actinomycetes, lichen and viruses have been reported eco-friendly. Moreover, the fungal system has emerged as an efficient system for nanoparticle synthesis as fungi possess distinctive characters including high wall binding capacity, easy to culture and simpler biomass handling, etc. In this review, we have discussed fungi as an important tool for the fabrication of nanoparticles. In addition, methods and mechanism for synthesis of nanoparticles and its potential applications have also been discussed.

This declaration, signed by an interdisciplinary task force of 234 experts from 83 different countries with different backgrounds, highlights the threat posed by antimicrobial resistance and the need for appropriate use of antibiotic agents and antifungal agents in hospitals worldwide especially focusing on surgical infections. As such, it is our intent to raise awareness among healthcare workers and improve antimicrobial prescribing. To facilitate its dissemination, the declaration was translated in different languages.