Preface

Bacterial strains' resistance to bactericides is a natural process that arises from the selection pressure of antibiotics against these pathogens. The continuous assault of drugs on bacteria prompts these organisms to develop various defense mechanisms, such as β-lactamase biosynthesis, which targets the hydrolysis of the β-lactam ring in different penicillin and carbapenems. Other resistance mechanisms exist, such as changes in cell membrane proteins or the increased activity of efflux pumps. These changes are derived from gene information from surviving bacteria to pharmacological treatments. The dissemination of this information is done very efficiently both by vertical and transverse routes. It is known that penicillin resistance emerged only a few years after the implementation of penicillin as a worldwide antibacterial drug. This was the beginning of a recurring phenomenon: a new drug was synthesized to treat a complex infection, and a time later, strains were resistant to this new medication. The misuse of antibiotics in livestock production and among humans, where antibiotic medication was unnecessary, has accelerated the emergence of Multidrug-Resistant Strains (MDR). Upon reaching concerning levels of bacterial resistance worldwide in 2017, the World Health Organization launched a list called ESKAPE, which identifies the main resistant drug bacteria that constitute a threat and require new drugs with new routes of action. Recently, the Centers for Disease Control and Prevention (CDC-USA), considering the rise of infections and deaths induced by microorganisms, classified the infections as urgent, serious, and concerning threats. It is worth noting that the CDC list differs from that proposed by the World Health Organization in 2017. As Chapter One indicates, antibiotic resistance is one of humanity's most immense health challenges. Virtually any bacterium can develop resistance, either by its evolution, by antibiotic pressure, or by genetic exchanges. Additionally, in this chapter, the author emphasizes the need for a one-health approach, addressing MDRO comprehensively in humans, animals, soil, water, and manure. The focus is on infection prevention and control, as well as optimizing antibiotic use to break the chain of resistance acquisition and transmission. In chapter two, the authors cover various aspects of phage therapy, including isolating and characterizing bacteriophages, the development of suitable formulations, and their administration for treating human infections. It also examines successful cases of phage therapy in treating life-threatening infections that cannot be cured with current antibiotics. Moreover, the chapter highlights the advantages and limitations of phage therapy compared to traditional antimicrobials. Chapter three focuses on the ongoing efforts and strategies to find new antibacterial compounds from natural sources. It discusses traditional methods and innovative techniques for dealing with non-culturable microorganisms. The positive outcomes of these approaches offer hope for a potential resurgence in discovering these valuable molecules, marking a second golden age for the field. As indicated in Chapter Four, clinicians have limited options when choosing antibiotics. The only available option for them is carbapenems. To develop new pharmacological strategies, clinicians must identify enzymes that break down these antimicrobials. Identifying these enzymes is crucial to reduce the selection pressure and ensure the correct use of antibiotics. The length of time a molecule stays active in the body is determined by its persistence. Clinical microbiology laboratories play a crucial role in guiding the administration of drugs. This chapter discusses the importance of carbapenemases-mediated resistance, its classification, impact, and detection strategies. Chapter Five identifies the most effective bactericidal-drug combinations against drug-resistant bacteria. Combining the carbapenem antibiotic and a β-lactamase inhibitor is considered one of the best combinations for clinical treatments. The chapter also discusses the use of Quorum-sensing inhibitors to inhibit virulence. Research on virulence inhibitors based on halogen furanone-type compounds has shown efficient virulence inhibition in vitro. However, there are currently no QS inhibitors in clinical evaluation.

Additionally, the synthesis of nanoparticles to counteract drug-resistant bacteria is explored. Nanoparticles synthesized with biological activity have shown significant results, especially those made from metals like silver and those synthesized using polymeric materials with biodegradable substances. Further studies are needed to determine their effectiveness and toxicity.

The editor would like to thank all the authors for their dedication and time in creating this book. He also thanks Ms. Graciela Flores-Rosete for compiling and organizing all the chapters.