Engineered Phages and Engineered and Recombinant Endolysins Against Carbapenem-Resistant Gram-Negative Bacteria: A Focused Review on Novel Antibacterial Strategies. - Related Documents




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975201.0000Engineered Phages and Engineered and Recombinant Endolysins Against Carbapenem-Resistant Gram-Negative Bacteria: A Focused Review on Novel Antibacterial Strategies. Antibiotic resistance has escalated globally, affecting not only commonly used antibiotics but also last-resort agents such as carbapenems and colistin. The rise of antibiotic-resistant bacteria has prompted microbiologists to devise new strategies, with bacteriophages emerging as one of the most promising options. Nevertheless, certain mechanisms have been identified in bacteria that confer resistance to phages. While phage resistance is currently less widespread than antibiotic resistance, challenges such as biofilm formation, newly emerging resistance mechanisms against phages, and the natural limitations of unmodified phages have driven the advancement of engineered phages. This study aims to examine the efficacy of engineered phages and both engineered and recombinant endolysins against carbapenem-resistant Gram-negative bacteria (CR-GNB). We performed a literature review through PubMed, Scopus, Web of Science, and Google Scholar, concentrating on studies that utilized these agents against carbapenem-resistant Gram-negative bacteria (CR-GNB). Reviewed studies indicate potential antibacterial activity of these agents against CR-GNB. By engineering and modifying phages, these agents exhibit improved antimicrobial efficacy, temperature stability, and membrane permeability. Furthermore, they demonstrate the ability to eliminate bacteria with multidrug-resistant (MDR) and extensively drug-resistant (XDR) profiles. These findings suggest the promising potential of engineered phages and endolysins for future clinical applications against CR-GNB.202540696543
980410.9999Antimicrobial Peptides as an Alternative for the Eradication of Bacterial Biofilms of Multi-Drug Resistant Bacteria. Bacterial resistance is an emergency public health problem worldwide, compounded by the ability of bacteria to form biofilms, mainly in seriously ill hospitalized patients. The World Health Organization has published a list of priority bacteria that should be studied and, in turn, has encouraged the development of new drugs. Herein, we explain the importance of studying new molecules such as antimicrobial peptides (AMPs) with potential against multi-drug resistant (MDR) and extensively drug-resistant (XDR) bacteria and focus on the inhibition of biofilm formation. This review describes the main causes of antimicrobial resistance and biofilm formation, as well as the main and potential AMP applications against these bacteria. Our results suggest that the new biomacromolecules to be discovered and studied should focus on this group of dangerous and highly infectious bacteria. Alternative molecules such as AMPs could contribute to eradicating biofilm proliferation by MDR/XDR bacteria; this is a challenging undertaking with promising prospects.202235336016
980020.9998Regulation of beta-lactamase induction in gram-negative bacteria: a key to understanding the resistance puzzle. Infections caused by drug-resistant microorganisms have posed a medical challenge since the advent of antimicrobial therapy. With the emergence of resistant strains, new antibiotics were available and introduced with great success until this decade. The appearance of multiresistant microorganisms pose a real and immediate public health concern. Are we entering into the post-antibiotic era? Will we return to pre-antimicrobial-era conditions, with morbidity and mortality resulting from untreatable infectious complications? The race to stay ahead of multiresistance involves not only continued drug development and selective use but elucidation of bacterial regulation of resistance. One way to ensure continued success of antimicrobial therapy is the identification of new bacterial targets--genes and their products involved in regulating or mediating resistance. Discussion will focus on one well-defined resistance mechanism in Gram-negative bacteria, the chromosomally located amp operon, responsible for one mechanism of beta-lactam resistance.19947723996
979630.9998Bacteriophage therapy to combat MDR non-fermenting Gram-negative bacteria causing nosocomial infections: recent progress and challenges. Clinicians face significant challenges in managing nosocomial infections, primarily due to antimicrobial resistance in multidrug-resistant bacteria. Regardless of the availability of a wide range of antimicrobials in the market, resistance is escalating rampantly with every passing day, which has become a global concern. Hence, it is essential to discover new and more efficient techniques to eliminate pathogens from healthcare settings. Along with eliminating pathogenic bacteria, mitigating their antimicrobial resistance with novel methods is very essential. Recently, bacteriophages have re-emerged as a promising therapeutic alternative to treat serious infections caused by bacterial pathogens. Bacteriophages were discovered for the first time a century ago, but their usage has recently regained more attention in treating bacterial pathogens. Bacteriophages also help in mitigating the worldwide problem of antibiotic resistance, particularly augmented by Gram-negative bacteria. This review discussed the advancements in the usage of bacteriophages in combating the antimicrobial resistance of multidrug-resistant Gram-negative bacteria, with a prime focus on Acinetobacter baumannii, Pseudomonas aeruginosa, and Burkholderia cepacia complex (Bcc), which are renowned non-fermenting Gram-negative bacteria (NFGNB) pathogens. Additionally, the effects of single phage, phage cocktails, and combination therapy with antibiotics on bacterial biofilms and polymicrobial biofilms are also discussed.202540478338
980640.9998Resistance of Gram-Positive Bacteria to Current Antibacterial Agents and Overcoming Approaches. The discovery of antibiotics has created a turning point in medical interventions to pathogenic infections, but unfortunately, each discovery was consistently followed by the emergence of resistance. The rise of multidrug-resistant bacteria has generated a great challenge to treat infections caused by bacteria with the available antibiotics. Today, research is active in finding new treatments for multidrug-resistant pathogens. In a step to guide the efforts, the WHO has published a list of the most dangerous bacteria that are resistant to current treatments and requires the development of new antibiotics for combating the resistance. Among the list are various Gram-positive bacteria that are responsible for serious healthcare and community-associated infections. Methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus faecium, and drug-resistant Streptococcus pneumoniae are of particular concern. The resistance of bacteria is an evolving phenomenon that arises from genetic mutations and/or acquired genomes. Thus, antimicrobial resistance demands continuous efforts to create strategies to combat this problem and optimize the use of antibiotics. This article aims to provide a review of the most critical resistant Gram-positive bacterial pathogens, their mechanisms of resistance, and the new treatments and approaches reported to circumvent this problem.202032586045
979750.9998Evaluation of Antibiotic Resistance Mechanisms in Gram-Positive Bacteria. The prevalence of resistance in Gram-positive bacterial infections is rapidly rising, presenting a pressing global challenge for both healthcare systems and economies. The WHO categorizes these bacteria into critical, high, and medium priority groups based on the urgency for developing new antibiotics. While the first priority pathogen list was issued in 2017, the 2024 list remains largely unchanged. Despite six years having passed, the progress that has been made in developing novel treatment approaches remains insufficient, allowing antimicrobial resistance to persist and worsen on a global scale. Various strategies have been implemented to address this growing threat by targeting specific resistance mechanisms. This review evaluates antimicrobial resistance (AMR) in Gram-positive bacteria, highlighting its critical impact on global health due to the rise of multidrug-resistant pathogens. It focuses on the unique cell wall structure of Gram-positive bacteria, which influences their identification and susceptibility to antibiotics. The review explores the mechanisms of AMR, including enzymatic inactivation, modification of drug targets, limiting drug uptake, and increased drug efflux. It also examines the resistance strategies employed by high-priority Gram-positive pathogens such as Staphylococcus aureus, Streptococcus pneumoniae, and Enterococcus faecium, as identified in the WHO's 2024 priority list.202439766587
980560.9998Molecular mechanisms of multidrug resistance in clinically relevant enteropathogenic bacteria (Review). Multidrug resistant (MDR) enteropathogenic bacteria are a growing problem within the clinical environment due to their acquired tolerance to a wide range of antibiotics, thus causing severe illnesses and a tremendous economic impact in the healthcare sector. Due to its difficult treatment, knowledge and understanding of the molecular mechanisms that confer this resistance are needed. The aim of the present review is to describe the mechanisms of antibiotic resistance from a genomic perspective observed in bacteria, including naturally acquired resistance. The present review also discusses common pharmacological and alternative treatments used in cases of infection caused by MDR bacteria, thus covering necessary information for the development of novel antimicrobials and adjuvant molecules inhibiting bacterial proliferation.202236561977
979570.9998Antibiotic resistance: how it arises, the current position and strategies for the future. After 70 years of antibiotic therapy, the threat of untreatable infections is again a reality with resistance to antibiotics increasing in both Gram positive and Gram negative bacteria. Antibiotic-resistant bacteria cause both community and healthcare associated infections, presenting challenges in treatment and management. The development of new and novel antibiotics, particularly for Gram negative bacteria, is worryingly lacking. This article reviews the current situation and examines future strategies to tackle the continued threat of bacterial resistance.200919835196
488780.9998Mechanisms of Bacterial Drug Resistance with Special Emphasis on Phenotypic and Molecular Characterization of Extended Spectrum Beta-lactamase. Antibiotics are designed to effectively treat bacterial infections while minimizing harm to the human body. They work by targeting specific components of bacteria or by disrupting essential processes such as cell wall synthesis, membrane function, protein production, and metabolic pathways. However, the misuse and overuse of antibiotics have led to the emergence of drug resistance in humans, animals, and agriculture, contributing to the global spread of this problem. Drug resistance can be either innate or acquired, with acquired resistance involving changes in the bacterial chromosomes or transferable elements. Bacterial species employ various mechanisms of drug resistance, including modifying the antibiotic targets, inactivating the drug, reducing uptake or increasing efflux, overexpressing the target, utilizing alternative pathways, and forming biofilms. One significant concern in the realm of drug resistance revolves around the emergence and proliferation of extended-spectrum beta-lactamases (ESBLs), a gene that is found in most gram-negative bacteria, primarily carried by Escherichia coli and Klebsiella pneumoniae in healthcare settings. ESBL-mediated resistance poses challenges for diagnosis, treatment, infection control, and antibiotic stewardship. Accurate detection of ESBL genes is crucial, and phenotypic methods are commonly used for initial screening. However, these methods have limitations, and confirmatory molecular techniques such as PCR and DNA sequencing are employed to accurately identify ESBL genes. Despite the significant global concerns surrounding ESBLs, they have spread worldwide, mainly facilitated by healthcare settings, inappropriate antimicrobial use, and host susceptibility. Addressing this issue requires implementing comprehensive measures, including enhanced surveillance, strict infection control practices, antibiotic stewardship programs, rapid diagnostic methods, alternative therapies, public education initiatives, and research focused on developing new drugs. Furthermore, collaboration among the healthcare, public health, and research sectors is pivotal in effectively combating the escalating threat posed by ESBL-mediated resistance. Antibiotics have revolutionized medical care by effectively treating bacterial infections. However, the emergence of ESBL gene resistance poses a global challenge that requires an integrated approach to prevent a threatening future.202438700878
487990.9998Prevalence of polymyxin resistance through the food chain, the global crisis. Antimicrobial resistance is one of the vital challenges facing global health today. Multi-drug resistant (MDR) infections are often treated with the narrow-spectrum drugs, colistin (polymyxin E) or polymyxin B, which are last-resort antibiotics for human therapeutics that are effective against Gram-negative bacteria. Unfortunately, resistance to these polymyxins has occurred because of selective pressure caused by the inappropriate use of those antibiotics, especially in farming. The mechanisms of resistance to polymyxins are mediated through intrinsic, mutational, or genetic alteration in chromosomal genes. The mechanism includes the regulatory network controlling chemical modifications of lipid A moiety of lipopolysaccharide, reducing the negative charge of lipid A and its affinity for polymyxins. Additionally, the unique mobile colistin/polymyxin B resistance (mcr) gene reported in Enterobacteriales is responsible for the horizontal dissemination of resistance to polymyxins via the food chain. There is now an urgent need to increase surveillance for detecting resistance to polymyxins. Therefore, this review presents an overview of presently available scientific literature on the mechanism of resistance to polymyxins, with their associated gene variants, evaluation methods, resistance transmission through the food chain via food bacteria, and related risk factors. We further focus on the significant implications of polymyxins usage in India and future views for food safety to preserve polymyxin activity.202235079146
9751100.9998Antibiotics-free compounds for managing carbapenem-resistant bacteria; a narrative review. Carbapenem-resistant (CR) Gram-negative bacteria have become a significant public health problem in the last decade. In recent years, the prevalence of CR bacteria has increased. The resistance to carbapenems could result from different mechanisms such as loss of porin, penicillin-binding protein alteration, carbapenemase, efflux pump, and biofilm community. Additionally, genetic variations like insertion, deletion, mutation, and post-transcriptional modification of corresponding coding genes could decrease the susceptibility of bacteria to carbapenems. In this regard, scientists are looking for new approaches to inhibit CR bacteria. Using bacteriophages, natural products, nanoparticles, disulfiram, N-acetylcysteine, and antimicrobial peptides showed promising inhibitory effects against CR bacteria. Additionally, the mentioned compounds could destroy the biofilm community of CR bacteria. Using them in combination with conventional antibiotics increases the efficacy of antibiotics, decreases their dosage and toxicity, and resensitizes CR bacteria to antibiotics. Therefore, in the present review article, we have discussed different aspects of non-antibiotic approaches for managing and inhibiting the CR bacteria and various methods and procedures used as an alternative for carbapenems against these bacteria.202439355778
4878110.9998Bacteria carrying mobile colistin resistance genes and their control measures, an updated review. The plasmid encoded mobile colistin resistance (MCRs) enzyme poses a significant challenge to the clinical efficacy of colistin, which is frequently employed as a last resort antibiotic for treating infections caused by multidrug resistant bacteria. This transferase catalyzes the addition of positively charged phosphoethanolamine to lipid A of the outer membrane of gram-negative bacteria, thereby facilitating the acquired colistin resistance. This review aims to summarize and critically discuss recent advancements in the distribution and pathogenesis of mcr-positive bacteria, as well as the various control measures available for treating these infections. In addition, the ecology of mcr genes, colistin-resistance mechanism, co-existence with other antibiotic resistant genes, and their impact on clinical treatment are also analyzed to address the colistin resistance crisis. These insights provide a comprehensive perspective on MCRs and serve as a valuable reference for future therapeutic approaches to effectively combat mcr-positive bacterial infections.202439516398
9801120.9998Problems and changing patterns of resistance with gram-negative bacteria. Throughout the antibiotic era, the emergence of drug-resistant bacteria has paralleled the development of new antimicrobial agents. As a result of selection pressures and invasive techniques that prolong the lives of seriously ill hospital patients, gram-negative bacilli have become the dominant causes of nosocomial infection. These microorganisms produce a diversity of antibiotic-inactivating enzymes. Moreover, the cell envelope of gram-negative bacteria provides a series of barriers that keep antibiotics from reaching their targets. Resistance factors can be transmitted among bacteria of different genera and species, thus conferring multidrug resistance. These problems continue to challenge scientists to better understand resistance mechanisms and to develop new compounds to circumvent them.19853909311
4253130.9998Molecular mechanisms of polymyxin resistance and detection of mcr genes. Antibiotic resistance is an ever-increasing global problem. Major commercial antibiotics often fail to fight common bacteria, and some pathogens have become multi-resistant. Polymyxins are potent bactericidal antibiotics against gram-negative bacteria. Known resistance to polymyxin includes intrinsic, mutational and adaptive mechanisms, with the recently described horizontally acquired resistance mechanisms. In this review, we present several strategies for bacteria to develop enhanced resistance to polymyxins, focusing on changes in the outer membrane, efflux and other resistance determinants. Better understanding of the genes involved in polymyxin resistance may pave the way for the development of new and effective antimicrobial agents. We also report novel in silico tested primers for PCR assay that may be able distinguish colistin-resistant isolates carrying the plasmid-encoded mcr genes and will assist in combating the spread of colistin resistance in bacteria.201930439931
9560140.9998The History of Colistin Resistance Mechanisms in Bacteria: Progress and Challenges. Since 2015, the discovery of colistin resistance genes has been limited to the characterization of new mobile colistin resistance (mcr) gene variants. However, given the complexity of the mechanisms involved, there are many colistin-resistant bacterial strains whose mechanism remains unknown and whose exploitation requires complementary technologies. In this review, through the history of colistin, we underline the methods used over the last decades, both old and recent, to facilitate the discovery of the main colistin resistance mechanisms and how new technological approaches may help to improve the rapid and efficient exploration of new target genes. To accomplish this, a systematic search was carried out via PubMed and Google Scholar on published data concerning polymyxin resistance from 1950 to 2020 using terms most related to colistin. This review first explores the history of the discovery of the mechanisms of action and resistance to colistin, based on the technologies deployed. Then we focus on the most advanced technologies used, such as MALDI-TOF-MS, high throughput sequencing or the genetic toolbox. Finally, we outline promising new approaches, such as omics tools and CRISPR-Cas9, as well as the challenges they face. Much has been achieved since the discovery of polymyxins, through several innovative technologies. Nevertheless, colistin resistance mechanisms remains very complex.202133672663
9791150.9998Beta-lactam resistance and the effectiveness of antimicrobial peptides against KPC-producing bacteria. Bacterial resistance is a problem that is giving serious cause for concern because bacterial strains such as Acinetobacter baumannii and Pseudomonas aeruginosa are difficult to treat and highly opportunistic. These bacteria easily acquire resistance genes even from other species, which confers greater persistence and tolerance towards conventional antibiotics. These bacteria have the highest death rate in hospitalized intensive care patients, so strong measures must be taken. In this review, we focus on the use of antimicrobial peptides (AMPs) as an alternative to traditional drugs, due to their rapid action and lower risk of generating resistance by microorganisms. We also present an overview of beta-lactams and explicitly explain the activity of AMPs against carbapenemase-producing bacteria as potential alternative agents for infection control.202236042694
9790160.9998Emerging antibiotic resistance: carbapenemase-producing enterobacteria. Bad new bugs, still no new drugs. Antimicrobial resistance (AMR) is a global health security threat requiring actions across government sectors and society. Many factors are involved in this phenomenon, being overuse of antibiotics, incorrect antibiotic prophylaxis, and use of antibiotics for zootechnic reasons the main causes of the increasing rate of multi-drug resistant (MDR) bacteria. The impact of resistance to antimicrobials is an important threat due also to the emergence of MDR Gram-negative bacteria resistant to carbapenems, and the lack of the research for new active molecules. The production of extended spectrum beta-lactamase enzymes has been the first threatening mechanism for Gram-negative resistance to antibiotics, which prompted the development of new classes of antibiotics such as carbapenems. Unfortunately, resistance to carbapenems developed because of multiple mechanisms including efflux pumps, porin mutations and enzyme production, being the latter particularly relevant in terms of diffusion due to the genes located within plasmids that drive their horizontal diffusion. In this scenario, antimicrobial stewardship programs (ASP) are a mandatory resource in fighting the resistance spread. The reduction of total amount of antibiotics administration in the hospital setting and guiding prescribers in the correct administration of antibiotics for the smallest period possible, at the correct dosage, can be defined as the first goals of an ASP. Anyway, in an efficacious ASP, apart from antibiotic administration, efforts must been made in ensuring the lowest probability of spreading of MDR by efficacious measures of isolation of carriers, and by offering tools for a rapid diagnosis of viral infections avoiding the administration of unnecessary antibiotics. A continuous audit of the ASP programs and a correct assessment of the allergy to drugs such as penicillin have to complete the program. Currently, only a few options are available for patients with an infection sustained by Gram-negative MDR bacteria. All the options actually available are based on the administration of colystin, an old drug whose real efficacy is reduced due to its relevant toxicity, or on the administration of recently proposed drugs such as ceftolozane-tazobactam, ceftazidime-avibactam and meropenem-vaborbactam. All these new drugs do not have a novel mechanism of action and have limited spectrum in term of activity against MDR bacteria. In conclusion, antimicrobial resistance is a global emergence and AMP is the most powerful tool actually available. Few limited options are available to treat infections due to Carbapenem Resistant Enterobacteria. Antimicrobial molecules with true novel mechanism of action are needed to win the fight against antimicrobial resistance.201931846984
4883170.9998New tools to mitigate drug resistance in Enterobacteriaceae - Escherichia coli and Klebsiella pneumoniae. Treatment to common bacterial infections are becoming ineffective of late, owing to the emergence and dissemination of antibiotic resistance globally. Escherichia coli and Klebsiella pneumoniae are the most notorious microorganisms and are among the critical priority pathogens listed by WHO in 2017. These pathogens are the predominant cause of sepsis, urinary tract infections (UTIs), pneumonia, meningitis and pyogenic liver abscess. Concern arises due to the resistance of bacteria to most of the beta lactam antibiotics like penicillin, cephalosporin, monobactams and carbapenems, even to the last resort antibiotics like colistin. Preventing influx by modulation of porins, extruding the antibiotics by overexpression of efflux pumps, mutations of drug targets/receptors, biofilm formation, altering the drug molecules and rendering them ineffective are few resistance mechanisms that are adapted by Enterobacteriaeceae upon exposure to antibiotics. The situation is exacerbated due to the process of horizontal gene transfer (HGT), wherein the genes encoding resistance mechanisms are transferred to the neighbouring bacteria through plasmids/phages/uptake of free DNA. Carbapenemases, other beta lactamases and mcr genes coding for colistin resistance are widely disseminated leading to limited/no therapeutic options against those infections. Development of new antibiotics can be viewed as a possible solution but it involves major investment, time and labour despite which, the bacteria can easily adapt to the new antibiotic and evolve resistance in a relatively short time. Targeting the resistance mechanisms can be one feasible alternative to tackle these multidrug resistant (MDR) pathogens. Removal of plasmid (plasmid curing) causing resistance, use of bacteriophages and bacteriotherapy can be other potential approaches to combat infections caused by MDR E. coli and K. pneumoniae. The present review discusses the efficacies of these therapies in mitigating these infections, which can be potentially used as an adjuvant therapy along with existing antibiotics.202335649163
9799180.9998Microbiology and drug resistance mechanisms of fully resistant pathogens. The acquisition of vancomycin resistance by Gram-positive bacteria and carbapenem resistance by Gram-negative bacteria has rendered some hospital-acquired pathogens impossible to treat. The resistance mechanisms employed are sophisticated and very difficult to overcome. Unless alternative treatment regimes are initiated soon, our inability to treat totally resistant bacteria will halt other developments in medicine. In the community, Gram-positive bacteria responsible for pneumonia could become totally resistant leading to increased mortality from this common infection, which would have a more immediate impact on our current lifestyles.200415451497
9520190.9998Role of Natural Product in Modulation of Drug Transporters and New Delhi Metallo-β Lactamases. A rapid growth in drug resistance has brought options for treating antimicrobial resistance to a halt. Bacteria have evolved to accumulate a multitude of genes that encode resistance for a single drug within a single cell. Alternations of drug transporters are one of the causes for the development of resistance in drug interactions. Conversely, the production of enzymes also inactivates most antibiotics. The discovery of newer classes of antibiotics and drugs from natural products is urgently needed. Alternative medicines play an integral role in countries across the globe but many require validation for treatment strategies. It is essential to explore this chemical diversity in order to find novel drugs with specific activities which can be used as alternative drug targets. This review describes the interaction of drugs with resistant pathogens with a special focus on natural product-derived efflux pump and carbapenemase inhibitors.201930987566