Additional information is available at the end of the chapter http://dx.doi.org/10.5772/58423 . IntroductionThe chemotherapy of infections caused by bacteria that inhabit intracellularly presents a number of uncommon challenges. Many bacteria have found the way to produce a silent infection inside the cells and to avoid from their bactericidal mechanisms. However many methods for diagnosing and treating these and other bacterial infections presently exist, there is an essential need for new and improved approaches for bacterial destruction. "lthough the therapeutic efficacy of drugs has been well recognized, inefficient delivery could result in insufficient therapeutic index. It is now clear that a nanotechnology-driven approach using nanoparticles to selectively target and destroy pathogenic bacteria can be successfully implemented. Nanotechnology is one approach to overcome challenges of conventional drug delivery systems based on the development and fabrication of nanostructures. Some challenges associated with the technology are as it relates to drug effectiveness, toxicity, stability, pharmacokinetics and drug regulatory control. Localized diseases such as infection and inflammation not only have perforated vasculature but also overexpress some epitopes or receptors that can be used as targets. Thus, nanomedicines can also be actively targeted to these locations. Various types of nanoparticulate systems have been tried as potential drug delivery systems, containing biodegradable polymeric nanoparticles, polymeric micelles, nanocapsules, nanogels, fullerenes, solid lipid nanoparticles SLN , nanoliposomes, dendrimers, metal nanoparticles and quantum dots. Nanoparticles have been found useful in the development of systemic, oral, pulmonary, transdermal and other administration routes to study drug targeting, the enhancement of drug bioavailability and protection of drug bioactivity and stability. In recent years, encapsulation of antimicrobial drugs in nanoparticle systems has emerged as an innovative and promising alternative that enhances therapeutic effectiveness

Even though the therapeutic efficacy of numerous antimicrobial drugs has been well established, inefficient delivery can result in an inadequate therapeutic index. Gold nanoparticles have unique physicochemical properties such as large surface area to mass ratio and functionalizable structure. These properties can be applied to facilitate the administration of antimicrobial drugs, thereby overcoming some of the limitations in traditional antimicrobial therapeutics. In this study, gold nanospheres were used as a drug carrier system for gentamicin delivery to Staphylococcal infected foci. Conjugation of gentamicin with gold nanospheres was performed in HEPES buffer. The attachment of gentamicin to gold nanospheres was confirmed by UV/Vis spectroscopy. The HPLC and atomic absorption spectrometer analyses showed that 347 gentamicin molecules were attached to each gold nanosphere. Minimum inhibitory concentration and minimum bactericidal concentration studies showed the enhanced antibacterial effect of gentamicin-gold nanospheres complex in comparison with free gentamicin. The biodistribution study showed the localization of the complex at the site of Staphylococcal infection foci with high sensitivity in mouse model.

Background:Wound infection is a common problem in hospitals and is typically caused by the antibiotic-resistant Staphylococcus aureus, which is a major pathogen for skin and soft tissue infections worldwide.Objectives:The aim of this study was to investigate the synergistic antibacterial effect of plant peptide MBP-1 and silver nanoparticles on infected wounds caused by S. aureus.Materials and Methods:The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of MBP-1 and silver nanoparticles both on their own and in combination form were determined against S. aureus via macrodilution and microdilution methods. The synergistic antibacterial effect of silver nanoparticles and MBP-1 was investigated on infected wounds caused by S. aureus in a mouse model.Results:The MIC and MBC of MBP-1 were found to be 0.6 and 0.7 mg/mL, respectively. MIC and MBC of silver nanoparticles were determined to be 6.25 and 12.5 mg/L, respectively. MIC and MBC of the silver nanoparticles and MBP-1 combination were found to be 3.125 mg/mL, 0.5 mg/L; and 6.25 mg/mL, 0.6 mg/L, respectively. The infected wound healed properly after the combined use of MBP-1 and silver nanoparticles.Conclusions:The synergistic effect was found on the healing of infected wounds caused by S. aureus by using an MBP-1 and silver nanoparticles combination in a mouse model.

An infectious disease that is transmitted from animals to humans and vice-versa is called zoonosis. Bacterial zoonotic diseases can re-emerge after they have been eradicated or controlled and are among the world's major health problems which inflict tremendous burden on healthcare systems. The first step to encounter such illnesses can be early and precise detection of bacterial pathogens to further prevent the following losses due to their infections. Although conventional methods for diagnosing pathogens, including culture-based, polymerase chain reaction-based, and immunological-based techniques, benefit from their advantages, they also have their own drawbacks, for example, taking long time to provide results, and requiring laborious work, expensive materials, and special equipment in certain conditions.Consequently, there is a greater tendency to introduce simple, innovative, quicker, accurate, and low-cost detection methods to effectively characterize the causative agents of infectious diseases. Biosensors, therefore, seem to practically be one of those novel promising diagnostic tools on this aim. These are effective and reliable elements with high sensitivity and specificity, that their usability can even be improved in medical diagnostic systems when empowered by nanoparticles. In the present review, recent advances in the development of several bio and nano biosensors, for rapid detection of zoonotic bacteria, have been discussed in details.

There is no optimal imaging method for the detection of unknown infectious foci in some diseases. This study introduces a novel method in X-ray imaging of infection foci due to Staphylococcus aureus by developing a contrast agent based on gold nanoparticles (GNPs). GNPs in spherical shape were synthesised by the reduction of tetrachloroauric acid with sodium citrate. Then gentamicin was bound directly to citrate functionalised GNPs and the complex was stabilised by polyethylene glycol. The interaction of gentamicin with GNPs was confirmed by ultraviolet-visible and Fourier transform infrared spectroscopies. The stability of complex was studied in human blood up to 6 h. The stability of conjugate was found to be high in human blood with no aggregation. The biodistribution study showed localisation of gentamicin-GNPs conjugate at the site of Staphylococcal infection. The infection site was properly visualised in X-ray images in mouse model using the gentamicin-GNPs conjugate as a contrast agent. The results demonstrated that one may consider the potential of new nanodrug as a contrast agent for X-ray imaging of infection foci in human beings which needs more investigations.