Chapters authored
Antibiotic Resistance among Escherichia coli: Isolates and Novel Approaches to the Control of E. coli Infections
Bacteria are the microorganisms that most frequently cause infectious diseases in humans. The synthesis of silver nanoparticles (AgNPs) has attracted interest due to the new and different physical and chemical characteristics with applications in new fields. AgNPs, alone or supported on ceramic, are used as antimicrobial fillers in textiles and polymers for food-packaging and biomedical applications, for antimicrobial paints, and potentially for drug delivery. The evaluation of mesoporous nanostructures or nanocomposites as FDU-12/lignin/silver was effective in inhibiting Staphylococcus aureus, E. coli, Enterococcus faecalis, and Candida albicans. The best results were achieved against the inhibition of E. coli and with the structures FDU-12/silver. In plates with FDU-12/lignin/silver, FDU-12, FDU-12/lignin, and the positive control, it was enumerated at 0, 6, 14, and 27 colonies, respectively. While the development of resistance to a new antibiotic is expected, the time course and degree of resistance are uncertain and depend on various factors. The application of AgNPs as nanocomposites can alter the expression of bacterial proteins and could be used for inactivation. This review explores such aspects and a number of factors arising like the use of nanostructures against E. coli, from the knowledge acquired.
Part of the book: Escherichia coli
Plant-Associated Microorganisms as a Potent Bio-Factory of Active Molecules against Multiresistant Pathogens
Antibiotic-resistant pathogens are a public health threat that has rapidly spread over decades due to continuous and uncontrolled administration of antimicrobial medicines, becoming an ever-increasing worldwide concern. Since the past decade, no significant innovations have been made, so the search for new compounds that face multidrug-resistant pathogens is critically important. Plant-symbiont microorganisms are capable of producing a variety of bioactive natural products, making it possible to treat several infectious diseases. Biotechnological processes using microorganisms have been increasing in recent years since the discovery of Paclitaxel, an important antimitotic produced by the endophyte Taxomyces andreanae. It was isolated for the first time from the native tree of Pacific Taxus brevifolia. Several studies have demonstrated the isolation and characterization of promising and potent substances capable of inhibiting these pathogens. In addition, both rhizospheric and endophytic communities represent an unexplored reserve of unique chemical structures for drug development. This chapter focuses on the potential of plant-derived microorganisms as a source of bioactive substances and the perspectives for further studies and their application.
Part of the book: Antimicrobial Resistance
Light and Phages on Tackle of Infectious Diseases
There has been an important increase in the emergence of resistance in microbial population worldwide. This trajectory needs, necessarily new approaches to treat infectious diseases. The ability to detect and prevent the evolutionary trajectories of microbial resistance would be of value. Photodynamic inactivation (PDI) represents an efficient alternative treatment for diseases caused by viruses, which can cause infections well documented in various mammals. PDI can kill cells after exposure with the appropriate photosensitizer (PS), light of adequate wavelength combined with the presence of oxygen, without inducing resistance. Cytotoxic reactive species formed interaction with vital biomolecules leading to irreversible microbial inactivation. Bacteriophages can act on delivering antimicrobial agents into bacteria, which consist in a likely instrument for the treatment of infectious diseases. Non-enveloped bacteriophages are more difficult to tolerate photoinactivation than enveloped phages, which makes them an important model tool to evaluate the efficiency of PDI therapy against viruses that cause diseases in humans. Combination of photosensitizers and bacteriophage therapy can be employed to eradicate biofilms, contributing to control of infections also caused by drug-resistant bacteria.
Part of the book: Bacteriophages in Therapeutics
Development of Antibiofilm Substances by Endophytic Microorganisms with an Emphasis on Medicine
The growing antimicrobial resistance and persistence of pathogenic microorganisms in infections–particularly in nosocomial infections–have become a major problem for public health worldwide. One of the main causes of these issues is the formation of biofilms, which are microbial communities associated with extracellular polymeric substances (EPS) that form a slimy extracellular matrix, causing the bacteria to become more tolerant to usual drugs in these structures. Thus, the search for new antibiofilm compounds is part of a strategy to deal with this problem. Endophytic microorganisms such as bacteria and fungi, mutualistically associated with plants, are sources of compounds with biological properties, including antimicrobials, and can be important allies in the synthesis of antibiofilm. These secondary metabolites can interfere with cell-to-cell communication and cell adhesion ability, promoting the dispersal of bacterial colonies and affecting biofilm. Since endophytes are cultivable in laboratory conditions, these microorganisms are environmentally friendly, as they do not contribute to pollution, are easy to handle and are produced on a large scale. Furthermore, metabolites from endophytes are of natural origin and may contribute to the reduced use of synthetic drugs. Considering these aspects, this chapter will focus on the characterization of endophytic microorganisms as potential active sources of antibiofilm and antimicrobial compounds with applications in medicine.
Part of the book: Focus on Bacterial Biofilms