Recent Advances in Understanding the Molecular Mechanisms of Multidrug Resistance and Novel Approaches of CRISPR/Cas9-Based Genome-Editing to Combat This Health Emergency. - Related Documents




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817401.0000Recent Advances in Understanding the Molecular Mechanisms of Multidrug Resistance and Novel Approaches of CRISPR/Cas9-Based Genome-Editing to Combat This Health Emergency. The rapid spread of multidrug resistance (MDR), due to abusive use of antibiotics has led to global health emergency, causing substantial morbidity and mortality. Bacteria attain MDR by different means such as antibiotic modification/degradation, target protection/modification/bypass, and enhanced efflux mechanisms. The classical approaches of counteracting MDR bacteria are expensive and time-consuming, thus, it is highly significant to understand the molecular mechanisms of this resistance to curb the problem from core level. The revolutionary approach of clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated sequence 9 (CRISPR/Cas9), considered as a next-generation genome-editing tool presents an innovative opportunity to precisely target and edit bacterial genome to alter their MDR strategy. Different bacteria possessing antibiotic resistance genes such as mecA, ermB, ramR, tetA, mqrB and bla(KPC) that have been targeted by CRISPR/Cas9 to re-sensitize these pathogens against antibiotics, such as methicillin, erythromycin, tigecycline, colistin and carbapenem, respectively. The CRISPR/Cas9 from S. pyogenes is the most widely studied genome-editing tool, consisting of a Cas9 DNA endonuclease associated with tracrRNA and crRNA, which can be systematically coupled as sgRNA. The targeting strategies of CRISPR/Cas9 to bacterial cells is mediated through phage, plasmids, vesicles and nanoparticles. However, the targeting approaches of this genome-editing tool to specific bacteria is a challenging task and still remains at a very preliminary stage due to numerous obstacles awaiting to be solved. This review elaborates some recent updates about the molecular mechanisms of antibiotic resistance and the innovative role of CRISPR/Cas9 system in modulating these resistance mechanisms. Furthermore, the delivery approaches of this genome-editing system in bacterial cells are discussed. In addition, some challenges and future prospects are also described.202438344439
816910.9998Engineered CRISPR-Cas systems for the detection and control of antibiotic-resistant infections. Antibiotic resistance is spreading rapidly around the world and seriously impeding efforts to control microbial infections. Although nucleic acid testing is widely deployed for the detection of antibiotic resistant bacteria, the current techniques-mainly based on polymerase chain reaction (PCR)-are time-consuming and laborious. There is an urgent need to develop new strategies to control bacterial infections and the spread of antimicrobial resistance (AMR). The CRISPR-Cas system is an adaptive immune system found in many prokaryotes that presents attractive opportunities to target and edit nucleic acids with high precision and reliability. Engineered CRISPR-Cas systems are reported to effectively kill bacteria or even revert bacterial resistance to antibiotics (resensitizing bacterial cells to antibiotics). Strategies for combating antimicrobial resistance using CRISPR (i.e., Cas9, Cas12, Cas13, and Cas14) can be of great significance in detecting bacteria and their resistance to antibiotics. This review discusses the structures, mechanisms, and detection methods of CRISPR-Cas systems and how these systems can be engineered for the rapid and reliable detection of bacteria using various approaches, with a particular focus on nanoparticles. In addition, we summarize the most recent advances in applying the CRISPR-Cas system for virulence modulation of bacterial infections and combating antimicrobial resistance.202134863214
817020.9998Exploring molecular mechanisms of drug resistance in bacteria and progressions in CRISPR/Cas9-based genome expurgation solutions. Antibiotic resistance in bacteria is a critical global health challenge, driven by molecular mechanisms such as genetic mutations, efflux pumps, enzymatic degradation of antibiotics, target site modifications, and biofilm formation. Horizontal gene transfer (HGT) further accelerates the spread of resistance genes across bacterial populations. These mechanisms contribute to the emergence of multidrug-resistant (MDR) strains, rendering conventional antibiotics ineffective. Recent advancements in CRISPR/Cas9-based genome editing offer innovative solutions to combat drug resistance. CRISPR/Cas9 enables precise targeting of resistance genes, facilitating their deletion or inactivation, and provides a potential method to eliminate resistance-carrying plasmids. Furthermore, phage-delivered CRISPR systems show promise in selectively killing resistant bacteria while leaving susceptible strains unaffected. Despite challenges such as efficient delivery, off-target effects, and potential bacterial resistance to CRISPR itself, ongoing research and technological innovations hold promise for using CRISPR-based antimicrobials to reverse bacterial drug resistance and develop more effective therapies. These abstract highlights the molecular mechanisms underlying bacterial drug resistance and explores how CRISPR/Cas9 technology could revolutionize treatment strategies against resistant pathogens.202540051841
921830.9998CRISPR-Cas System: A New Dawn to Combat Antibiotic Resistance. Antimicrobial resistance (AMR) can potentially harm global public health. Horizontal gene transfer (HGT), which speeds up the emergence of AMR and increases the burden of drug resistance in mobile genetic elements (MGEs), is the primary method by which AMR genes are transferred across bacterial pathogens. New approaches are urgently needed to halt the spread of bacterial diseases and antibiotic resistance. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR), an RNA-guided adaptive immune system, protects prokaryotes from foreign DNA like plasmids and phages. This approach may be essential in limiting horizontal gene transfer and halting the spread of antibiotic resistance. The CRISPR-Cas system has been crucial in identifying and understanding resistance mechanisms and developing novel therapeutic approaches. This review article investigates the CRISPR-Cas system's potential as a tool to combat bacterial AMR. Antibiotic-resistant bacteria can be targeted and eliminated by the CRISPR-Cas system. It has been proven to be an efficient method for removing carbapenem-resistant plasmids and regaining antibiotic susceptibility. The CRISPR-Cas system has enormous potential as a weapon against bacterial AMR. It precisely targets and eliminates antibiotic-resistant bacteria, facilitates resistance mechanism identification, and offers new possibilities in diagnostics and therapeutics.202438605260
817240.9998From resistance to remedy: the role of clustered regularly interspaced short palindromic repeats system in combating antimicrobial resistance-a review. The growing challenge of antimicrobial resistance (AMR) poses a significant and increasing risk to public health worldwide, necessitating innovative strategies to restore the efficacy of antibiotics. The precise genome-editing abilities of the CRISPR-Cas system have made it a potent instrument for directly targeting and eliminating antibiotic resistance genes. This review explored the mechanisms and applications of CRISPR-Cas systems in combating AMR. The latest developments in CRISPR technology have broadened its potential use, encompassing programmable antibacterial agents and improved diagnostic methods for antibiotic-resistant infections. Nevertheless, several challenges must be overcome for clinical success, including the survival of resistant bacteria, generation of anti-CRISPR proteins that reduce effectiveness, and genetic modifications that change target sequences. Additionally, the efficacy of CRISPR-Cas systems differs across bacterial species, making their universal application challenging. After overcoming these challenges, CRISPR-Cas has the potential to revolutionize AMR treatment, restore antibiotic efficacy, and reshape infection control.202539404843
817350.9998Advancing Antibacterial Strategies: CRISPR-Phage-Mediated Gene Therapy Targeting Bacterial Resistance Genes. One of the most significant issues facing the world today is antibiotic resistance, which makes it increasingly difficult to treat bacterial infections. Regular antibiotics no longer work against many bacteria, affecting millions of people. A novel approach known as CRISPR-phage therapy may be beneficial. This technique introduces a technology called CRISPR into resistant bacteria using bacteriophages. The genes that cause bacteria to become resistant to antibiotics can be identified and cut using CRISPR. This enables antibiotics to function by inhibiting the bacteria. This approach is highly precise, unlike conventional antibiotics, so it doesn't damage our bodies' beneficial bacteria. Preliminary studies and limited clinical trials suggest that this technique can effectively target drug-resistant bacteria such as Klebsiella pneumoniae and Methicillinresistant Staphylococcus aureus (MRSA). However, challenges in phage engineering, host delivery, and the growing threat of bacterial CRISPR resistance demand urgent and strategic innovation. Our perspective underscores that without proactive resolution of these hurdles, the current hopefulness could disappear. Looking ahead, integrating next-generation Cas effectors, non-DSB editors, and resistance monitoring frameworks could transform CRISPR-phage systems from an experimental novelty into a clinical mainstay. This shift will require not only scientific ingenuity but also coordinated advances in regulatory, translational, and manufacturing efforts.202540990280
816660.9998A Comprehensive Review of Molecular Mechanisms Leading to the Emergence of Multidrug Resistance in Bacteria. Multidrug resistance (MDR) in bacteria poses a serious global health threat, compromising the effectiveness of antibiotics. MDR causes approximately 700,000 deaths annually, with MDR tuberculosis alone claiming 230,000 lives. While bacteria inherently possess intrinsic resistance, acquired resistance stands out as the primary culprit in MDR development. Acquired resistance mechanisms mediated by the bacterial cell wall, nucleic acids, and proteins play a pivotal role in the genesis of MDR. Bacteria can modify their cell wall structure, produce resistant enzymes, exhibit mutations in antibiotic-targeted genes, and acquire resistant genes through horizontal gene transfer. Bacteria can produce proteins that act as enzymes, chemically modifying or directly degrading the antibiotic molecules, leading to the loss of their functionality. Apart from these mechanisms, biofilms also play a pivotal role in MDR expansion. Despite the development of several antibiotics since the discovery of penicillin, continuous structural and molecular modifications in bacteria render these antibiotics ineffective against MDR. The most recent approaches such as clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated proteins (CRISPR-Cas), nanotechnology, a combination of CRISPR-Cas, and nanoparticles, show promise in treating MDR. Thus, this review delves deep into the molecular mechanisms of MDR, emphasizing the limitations of current antibiotics due to bacterial evolution and highlighting current strategies in the fight against MDR bacteria. This will drive comprehensive research to uncover additional resistance mechanisms and develop innovative strategies to combat resistant bacteria effectively. SUPPLEMENTARY INFORMATION: The online version supplementary material available at 10.1007/s12088-024-01384-6.202540655388
921670.9997Mitigating Antibiotic Resistance: The Utilization of CRISPR Technology in Detection. Antibiotics, celebrated as some of the most significant pharmaceutical breakthroughs in medical history, are capable of eliminating or inhibiting bacterial growth, offering a primary defense against a wide array of bacterial infections. However, the rise in antimicrobial resistance (AMR), driven by the widespread use of antibiotics, has evolved into a widespread and ominous threat to global public health. Thus, the creation of efficient methods for detecting resistance genes and antibiotics is imperative for ensuring food safety and safeguarding human health. The clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated proteins (Cas) systems, initially recognized as an adaptive immune defense mechanism in bacteria and archaea, have unveiled their profound potential in sensor detection, transcending their notable gene-editing applications. CRISPR/Cas technology employs Cas enzymes and guides RNA to selectively target and cleave specific DNA or RNA sequences. This review offers an extensive examination of CRISPR/Cas systems, highlighting their unique attributes and applications in antibiotic detection. It outlines the current utilization and progress of the CRISPR/Cas toolkit for identifying both nucleic acid (resistance genes) and non-nucleic acid (antibiotic micromolecules) targets within the field of antibiotic detection. In addition, it examines the current challenges, such as sensitivity and specificity, and future opportunities, including the development of point-of-care diagnostics, providing strategic insights to facilitate the curbing and oversight of antibiotic-resistance proliferation.202439727898
918980.9997CRISPR-Cas9 System: A Prospective Pathway toward Combatting Antibiotic Resistance. Antibiotic resistance is rising to dangerously high levels throughout the world. To cope with this problem, scientists are working on CRISPR-based research so that antibiotic-resistant bacteria can be killed and attacked almost as quickly as antibiotic-sensitive bacteria. Nuclease activity is found in Cas9, which can be programmed with a specific target sequence. This mechanism will only attack pathogens in the microbiota while preserving commensal bacteria. This article portrays the delivery methods used in the CRISPR-Cas system, which are both viral and non-viral, along with its implications and challenges, such as microbial dysbiosis, off-target effects, and failure to counteract intracellular infections. CRISPR-based systems have a lot of applications, such as correcting mutations, developing diagnostics for infectious diseases, improving crops productions, improving breeding techniques, etc. In the future, CRISPR-based systems will revolutionize the world by curing diseases, improving agriculture, and repairing genetic disorders. Though all the drawbacks of the technology, CRISPR carries great potential; thus, the modification and consideration of some aspects could result in a mind-blowing technique to attain all the applications listed and present a game-changing potential.202337370394
918890.9997CRISPR-Cas system, antibiotic resistance and virulence in bacteria: Through a common lens. CRISPR-Cas system, antibiotic resistance and virulence are different modes of survival for the bacteria. CRISPR-Cas is an adaptive immune system that can degrade foreign DNA, antibiotic resistance helps bacteria to evade drugs that can threaten their existence and virulence determinants are offensive tools that can facilitate the establishment of infection by pathogens. This chapter focuses on these three aspects, providing insights about the CRISPR system and resistance mechanisms in brief, followed by understanding the synergistic or antagonistic relationship of resistance and virulence determinants in connection to the CRISPR system. We have addressed the discussion of this evolving topic through specific examples and studies. Different approaches for successful detection of this unique defense system in bacteria and various applications of the CRISPR-Cas systems to show how it can be harnessed to tackle the increasing problem of antibiotic resistance have been put forth. World Health Organization has declared antibiotic resistance as a serious global problem of the 21st century. As antibiotic-resistant bacteria increase their footprint across the globe, newer tools such as the CRISPR-Cas system hold immense promise to tackle this problem.202133685595
9217100.9997Role of CRISPR-Cas systems and anti-CRISPR proteins in bacterial antibiotic resistance. The emergence and development of antibiotic resistance in bacteria is a serious threat to global public health. Antibiotic resistance genes (ARGs) are often located on mobile genetic elements (MGEs). They can be transferred among bacteria by horizontal gene transfer (HGT), leading to the spread of drug-resistant strains and antibiotic treatment failure. CRISPR (clustered regularly interspaced short palindromic repeats)-Cas (CRISPR-associated genes) is one of the many strategies bacteria have developed under long-term selection pressure to restrict the HGT. CRISPR-Cas systems exist in about half of bacterial genomes and play a significant role in limiting the spread of antibiotic resistance. On the other hand, bacteriophages and other MGEs encode a wide range of anti-CRISPR proteins (Acrs) to counteract the immunity of the CRISPR-Cas system. The Acrs could decrease the CRISPR-Cas system's activity against phages and facilitate the acquisition of ARGs and virulence traits for bacteria. This review aimed to assess the relationship between the CRISPR-Cas systems and Acrs with bacterial antibiotic resistance. We also highlighted the CRISPR technology and Acrs to control and prevent antibacterial resistance. The CRISPR-Cas system can target nucleic acid sequences with high accuracy and reliability; therefore, it has become a novel gene editing and gene therapy tool to prevent the spread of antibiotic resistance. CRISPR-based approaches may pave the way for developing smart antibiotics, which could eliminate multidrug-resistant (MDR) bacteria and distinguish between pathogenic and beneficial microorganisms. Additionally, the engineered anti-CRISPR gene-containing phages in combination with antibiotics could be used as a cutting-edge treatment approach to reduce antibiotic resistance.202439149034
8171110.9997Advancements in CRISPR-Cas-based strategies for combating antimicrobial resistance. Multidrug resistance (MDR) in bacteria presents a significant global health threat, driven by the widespread dissemination of antibiotic-resistant genes (ARGs). The CRISPR-Cas system, known for its precision and adaptability, holds promise as a tool to combat antimicrobial resistance (AMR). Although previous studies have explored the use of CRISPR-Cas to target bacterial genomes or plasmids harboring resistance genes, the application of CRISPR-Cas-based antimicrobial therapies is still in its early stages. Challenges such as low efficiency and difficulties in delivering CRISPR to bacterial cells remain. This review provides an overview of the CRISPR-Cas system, highlights recent advancements in CRISPR-Cas-based antimicrobials and delivery strategies for combating AMR. The review also discusses potential challenges for the future development of CRISPR-Cas-based antimicrobials. Addressing these challenges would enable CRISPR therapies to become a practical solution for treating AMR infections in the future.202540440869
8262120.9997Advances in CRISPR-Cas systems for human bacterial disease. Prokaryotic adaptive immune systems called CRISPR-Cas systems have transformed genome editing by allowing for precise genetic alterations through targeted DNA cleavage. This system comprises CRISPR-associated genes and repeat-spacer arrays, which generate RNA molecules that guide the cleavage of invading genetic material. CRISPR-Cas is classified into Class 1 (multi-subunit effectors) and Class 2 (single multi-domain effectors). Its applications span combating antimicrobial resistance (AMR), targeting antibiotic resistance genes (ARGs), resensitizing bacteria to antibiotics, and preventing horizontal gene transfer (HGT). CRISPR-Cas3, for example, effectively degrades plasmids carrying resistance genes, providing a precise method to disarm bacteria. In the context of ESKAPE pathogens, CRISPR technology can resensitize bacteria to antibiotics by targeting specific resistance genes. Furthermore, in tuberculosis (TB) research, CRISPR-based tools enhance diagnostic accuracy and facilitate precise genetic modifications for studying Mycobacterium tuberculosis. CRISPR-based diagnostics, leveraging Cas endonucleases' collateral cleavage activity, offer highly sensitive pathogen detection. These advancements underscore CRISPR's transformative potential in addressing AMR and enhancing infectious disease management.202439266183
9186130.9997From Gene Editing to Biofilm Busting: CRISPR-CAS9 Against Antibiotic Resistance-A Review. In recent decades, the development of novel antimicrobials has significantly slowed due to the emergence of antimicrobial resistance (AMR), intensifying the global struggle against infectious diseases. Microbial populations worldwide rapidly develop resistance due to the widespread use of antibiotics, primarily targeting drug-resistant germs. A prominent manifestation of this resistance is the formation of biofilms, where bacteria create protective layers using signaling pathways such as quorum sensing. In response to this challenge, the CRISPR-Cas9 method has emerged as a ground-breaking strategy to counter biofilms. Initially identified as the "adaptive immune system" of bacteria, CRISPR-Cas9 has evolved into a state-of-the-art genetic engineering tool. Its exceptional precision in altering specific genes across diverse microorganisms positions it as a promising alternative for addressing antibiotic resistance by selectively modifying genes in diverse microorganisms. This comprehensive review concentrates on the historical background, discovery, developmental stages, and distinct components of CRISPR Cas9 technology. Emphasizing its role as a widely used genome engineering tool, the review explores how CRISPR Cas9 can significantly contribute to the targeted disruption of genes responsible for biofilm formation, highlighting its pivotal role in reshaping strategies to combat antibiotic resistance and mitigate the challenges posed by biofilm-associated infectious diseases.202438702575
9399140.9997Inhibition of Replication Fork Formation and Progression: Targeting the Replication Initiation and Primosomal Proteins. Over 1.2 million deaths are attributed to multi-drug-resistant (MDR) bacteria each year. Persistence of MDR bacteria is primarily due to the molecular mechanisms that permit fast replication and rapid evolution. As many pathogens continue to build resistance genes, current antibiotic treatments are being rendered useless and the pool of reliable treatments for many MDR-associated diseases is thus shrinking at an alarming rate. In the development of novel antibiotics, DNA replication is still a largely underexplored target. This review summarises critical literature and synthesises our current understanding of DNA replication initiation in bacteria with a particular focus on the utility and applicability of essential initiation proteins as emerging drug targets. A critical evaluation of the specific methods available to examine and screen the most promising replication initiation proteins is provided.202337240152
9398150.9997Effectiveness of CRISPR-Cas in Sensitizing Bacterial Populations with Plasmid-Encoded Antimicrobial Resistance. The spread of bacteria resistant to antibiotics poses a serious threat to human health. Genes that encode antibiotic resistance are often harbored on plasmids, extra-chromosomal DNA molecules found in bacteria. The emergence of multiresistance plasmids is particularly problematic and demands the development of new antibiotics and alternative strategies. CRISPR-Cas derived tools with their sequence specificity offer a promising new approach to combating antibiotic resistance. By introducing CRISPR-Cas encoding plasmids that %specifically target antibiotic resistance genes on plasmids, the susceptibility of bacteria to conventional antibiotics can be restored. However, genetic variation within bacterial populations can hinder the effectiveness of such CRISPR-Cas tools by allowing some mutant plasmids to evade CRISPR-mediated cleaving or gene silencing. In this study, we develop a model to test the effectiveness of CRISPR-Cas in sensitizing bacterial populations carrying resistance on non-transmissible plasmids and assess the success probability of a subsequent treatment with conventional antibiotics. We evaluate this probability according to the target interference mechanism, the copy number of the resistance-encoding plasmid, and its compatibility with the CRISPR-Cas encoding plasmid. Our results identify promising approaches to revert antibiotic resistance with CRISPR-Cas encoding plasmids: A DNA-cleaving CRISPR-Cas system on a plasmid incompatible with the targeted plasmid is most effective for low copy numbers, while for resistance plasmids with higher copy numbers gene silencing by CRISPR-Cas systems encoded on compatible plasmids is the superior solution.202540985758
9559160.9997CRISPR-Cas Systems in the Fight Against Antimicrobial Resistance: Current Status, Potentials, and Future Directions. BACKGROUND: Antimicrobial resistance (AMR) is a critical global health concern that threatens the efficacy of existing antibiotics and poses significant challenges to public health and the economy worldwide. This review explores the potential of CRISPR-Cas systems as a novel approach to combating AMR and examines current applications, limitations, and prospects. METHODS: A comprehensive literature search was conducted across multiple databases, including PubMed, Google Scholar, Scopus, and Web of Science, covering publications published from 2014 to August 2024. This review focuses on CRISPR-Cas technologies and their applications in AMR. RESULTS: CRISPR-Cas systems have demonstrated efficacy in combating antimicrobial resistance by targeting and eliminating antibiotic-resistance genes. For example, studies have shown that CRISPR-Cas9 can effectively target and eliminate colistin resistance genes in MCR-1 plasmids, restoring susceptibility to carbapenems in bacteria such as E. coli and Klebsiella pneumoniae. Further molecular findings highlight the impact of CRISPR-Cas systems on various bacterial species, such as Enterococcus faecalis, in which CRISPR systems play a crucial role in preventing the acquisition of resistance genes. The effectiveness of CRISPR-Cas in targeting these genes varies due to differences in CRISPR locus formation among bacterial species. For instance, variations in CRISPR loci influence the targeting of resistance genes in E. faecalis, and CRISPR-Cas9 successfully reduces resistance by targeting genes such as tetM and ermB. CONCLUSION: CRISPR-Cas systems are promising for fighting AMR by targeting and eliminating antibiotic-resistant genes, as demonstrated by the effective targeting of colistin resistance genes on MCR-1 plasmids and their similar activities. However, the effectiveness of CRISPR-Cas is affected by variations in the CRISPR loci among bacterial species. Challenges persist, such as optimizing delivery methods and addressing off-target effects to ensure the safety and precision of CRISPR-Cas systems in clinical settings.202439619730
8168170.9997Understanding antimicrobial resistance (AMR) mechanisms and advancements in AMR diagnostics. The overuse and abuse of antibiotics, which results in the evolution of resistant microorganisms, is the primary cause of the global health catastrophe known as antimicrobial resistance (AMR). The enzymatic breakdown of antibiotics, target site modification, efflux pump overexpression, and the formation of biofilm are some of the mechanisms responsible for acquiring antimicrobial resistance (AMR). These mechanisms enable bacteria to evade or neutralize the effects of antimicrobial agents, complicating treatment options and increasing mortality rates. The rapid dissemination of resistance genes via horizontal gene transfer further exacerbates the problem, necessitating urgent intervention. Advanced AMR diagnostics are transforming the fight against antimicrobial resistance. Biosensors enable rapid, point-of-care detection; Cluster regularly interspaced short palindromic repeat (CRISPR) technologies offer precise identification of resistance genes; and mass spectrometry provides fast, accurate profiling. Automated systems streamline workflows and boost throughput, while flow cytometry delivers real-time, single-cell analysis of phenotypic resistance. Together, these innovations accelerate detection and support targeted antimicrobial stewardship, essential for combating the global AMR threat. This review covers the mechanisms underlying antimicrobial resistance (AMR) and recent advancements in AMR diagnostic technologies.202540544537
9235180.9997Investigating the Genomic Background of CRISPR-Cas Genomes for CRISPR-Based Antimicrobials. CRISPR-Cas systems are an adaptive immunity that protects prokaryotes against foreign genetic elements. Genetic templates acquired during past infection events enable DNA-interacting enzymes to recognize foreign DNA for destruction. Due to the programmability and specificity of these genetic templates, CRISPR-Cas systems are potential alternative antibiotics that can be engineered to self-target antimicrobial resistance genes on the chromosome or plasmid. However, several fundamental questions remain to repurpose these tools against drug-resistant bacteria. For endogenous CRISPR-Cas self-targeting, antimicrobial resistance genes and functional CRISPR-Cas systems have to co-occur in the target cell. Furthermore, these tools have to outplay DNA repair pathways that respond to the nuclease activities of Cas proteins, even for exogenous CRISPR-Cas delivery. Here, we conduct a comprehensive survey of CRISPR-Cas genomes. First, we address the co-occurrence of CRISPR-Cas systems and antimicrobial resistance genes in the CRISPR-Cas genomes. We show that the average number of these genes varies greatly by the CRISPR-Cas type, and some CRISPR-Cas types (IE and IIIA) have over 20 genes per genome. Next, we investigate the DNA repair pathways of these CRISPR-Cas genomes, revealing that the diversity and frequency of these pathways differ by the CRISPR-Cas type. The interplay between CRISPR-Cas systems and DNA repair pathways is essential for the acquisition of new spacers in CRISPR arrays. We conduct simulation studies to demonstrate that the efficiency of these DNA repair pathways may be inferred from the time-series patterns in the RNA structure of CRISPR repeats. This bioinformatic survey of CRISPR-Cas genomes elucidates the necessity to consider multifaceted interactions between different genes and systems, to design effective CRISPR-based antimicrobials that can specifically target drug-resistant bacteria in natural microbial communities.202235692726
9476190.9997Phage design and directed evolution to evolve phage for therapy. Phage therapy or Phage treatment is the use of bacteriolysing phage in treating bacterial infections by using the viruses that infects and kills bacteria. This technique has been studied and practiced very long ago, but with the advent of antibiotics, it has been neglected. This foregone technique is now witnessing a revival due to development of bacterial resistance. Nowadays, with the awareness of genetic sequence of organisms, it is required that informed choices of phages have to be made for the most efficacious results. Furthermore, phages with the evolving genes are taken into consideration for the subsequent improvement in treating the patients for bacterial diseases. In addition, direct evolution methods are increasingly developing, since these are capable of creating new biological molecules having changed or unique activities, such as, improved target specificity, evolution of novel proteins with new catalytic properties or creation of nucleic acids that are capable of recognizing required pathogenic bacteria. This system is incorporates continuous evolution such as protein or genes are put under continuous evolution by providing continuous mutagenesis with least human intervention. Although, this system providing continuous directed evolution is very effective, it imposes some challenges due to requirement of heavy investment of time and resources. This chapter focuses on development of phage as a therapeutic agent against various bacteria causing diseases and it improvement using direct evolution of proteins and nucleic acids such that they target specific organisms.202337739551