MCRS - Word Related Documents




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503400.9341Resensitizing carbapenem- and colistin-resistant bacteria to antibiotics using auranofin. Global emergence of Gram-negative bacteria carrying the plasmid-borne resistance genes, bla(MBL) and mcr, raises a significant challenge to the treatment of life-threatening infections by the antibiotics, carbapenem and colistin (COL). Here, we identify an antirheumatic drug, auranofin (AUR) as a dual inhibitor of metallo-β-lactamases (MBLs) and mobilized colistin resistance (MCRs), two resistance enzymes that have distinct structures and substrates. We demonstrate that AUR irreversibly abrogates both enzyme activity via the displacement of Zn(II) cofactors from their active sites. We further show that AUR synergizes with antibiotics on killing a broad spectrum of carbapenem and/or COL resistant bacterial strains, and slows down the development of β-lactam and COL resistance. Combination of AUR and COL rescues all mice infected by Escherichia coli co-expressing MCR-1 and New Delhi metallo-β-lactamase 5 (NDM-5). Our findings provide potential therapeutic strategy to combine AUR with antibiotics for combating superbugs co-producing MBLs and MCRs.202033067430
154110.9305Novel KPC-2 plasmid in a clinical Salmonella Rissen selected by antibiotic pressure. In this work, we present the genomic characterization of a clinical Salmonella enterica serovar Rissen isolate harboring a novel IncN2 plasmid carrying the blaKPC-2 gene. The identified plasmid (pSEay-KPC) also encoded additional resistance genes, including blaACC-1, blaTEM-1, and qnrB. The pSEay-KPC conferred broad-spectrum antimicrobial resistance, allowing the pathogen to survive two consecutive antibiotic therapies with ceftriaxone and ciprofloxacin. Effective treatment was ultimately achieved with meropenem-vaborbactam, a last-resort agent. These findings highlight IncN2 plasmids as potent vectors for the spread of clinically significant resistance genes, enabling bacteria to evade frontline antimicrobials and complicating infection management.202541103243
815620.9298Innovative Delivery System Combining CRISPR-Cas12f for Combatting Antimicrobial Resistance in Gram-Negative Bacteria. Antimicrobial resistance poses a significant global challenge, demanding innovative approaches, such as the CRISPR-Cas-mediated resistance plasmid or gene-curing system, to effectively combat this urgent crisis. To enable successful curing of antimicrobial genes or plasmids through CRISPR-Cas technology, the development of an efficient broad-host-range delivery system is paramount. In this study, we have successfully designed and constructed a novel functional gene delivery plasmid, pQ-mini, utilizing the backbone of a broad-host-range Inc.Q plasmid. Moreover, we have integrated the CRISPR-Cas12f system into the pQ-mini plasmid to enable gene-curing in broad-host of bacteria. Our findings demonstrate that pQ-mini facilitates the highly efficient transfer of genetic elements to diverse bacteria, particularly in various species in the order of Enterobacterales, exhibiting a broader host range and superior conjugation efficiency compared to the commonly used pMB1-like plasmid. Notably, pQ-mini effectively delivers the CRISPR-Cas12f system to antimicrobial-resistant strains, resulting in remarkable curing efficiencies for plasmid-borne mcr-1 or bla(KPC) genes that are comparable to those achieved by the previously reported pCasCure system. In conclusion, our study successfully establishes and optimizes pQ-mini as a broad-host-range functional gene delivery vector. Furthermore, in combination with the CRISPR-Cas system, pQ-mini demonstrates its potential for broad-host delivery, highlighting its promising role as a novel antimicrobial tool against the growing threat of antimicrobial resistance.202438863339
249630.9296Treatment of Bloodstream Infections Due to Gram-Negative Bacteria with Difficult-to-Treat Resistance. The rising incidence of bloodstream infections (BSI) due to Gram-negative bacteria (GNB) with difficult-to-treat resistance (DTR) has been recognized as a global emergency. The aim of this review is to provide a comprehensive assessment of the mechanisms of antibiotic resistance, epidemiology and treatment options for BSI caused by GNB with DTR, namely extended-spectrum Beta-lactamase-producing Enterobacteriales; carbapenem-resistant Enterobacteriales; DTR Pseudomonas aeruginosa; and DTR Acinetobacter baumannii.202032971809
249340.9295Multidrug-resistant hypervirulent Klebsiella pneumoniae: an evolving superbug. Multidrug-resistant hypervirulent Klebsiella pneumoniae (MDR-hvKP) combines high pathogenicity with multidrug resistance to become a new superbug. MDR-hvKP reports continue to emerge, shattering the perception that hypervirulent K. pneumoniae (hvKP) strains are antibiotic sensitive. Patients infected with MDR-hvKP strains have been reported in Asia, particularly China. Although hvKP can acquire drug resistance genes, MDR-hvKP seems to be more easily transformed from classical K. pneumoniae (cKP), which has a strong gene uptake ability. To better understand the biology of MDR-hvKP, this review discusses the virulence factors, resistance mechanisms, formation pathways, and identification of MDR-hvKP. Given their destructive and transmissible potential, continued surveillance of these organisms and enhanced control measures should be prioritized.202540135944
487850.9292Bacteria 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
977260.9290Naringenin Microsphere as a Novel Adjuvant Reverses Colistin Resistance via Various Strategies against Multidrug-Resistant Klebsiella pneumoniae Infection. The efficacy of colistin, the last option against multidrug-resistant (MDR) Gram-negative bacteria, is severely threatened by the prevalence of plasmid- or chromosome-mediated colistin resistance genes. Herein, naringenin has dramatically restored colistin sensitivity against colistin-resistant Klebsiella pneumoniae infection without affecting bacterial viability, inducing resistance and causing obvious cell toxicity. Mechanism analysis reveals that naringenin potentiates colistin activity by multiple strategies including inhibition of mobilized colistin resistance gene activity, repression of two-component system regulation, and acceleration of reactive oxygen species-mediated oxidative damage. A lung-targeted delivery system of naringenin microspheres has been designed to facilitate naringenin bioavailability, accompanied by an effective potentiation of colistin for Klebsiella pneumoniae infection. Consequently, a new recognition of naringenin microspheres has been elucidated to restore colistin efficacy against colistin-resistant Gram-negative pathogens, which may be an effective strategy of developing potential candidates for MDR Gram-negative bacteria infection.202236530172
503270.9290Hijacking a small plasmid to confer high-level resistance to aztreonam-avibactam and ceftazidime-avibactam. Acquired β-lactamase-encoding genes are typically carried by large plasmids in Gram-negative bacteria, which also commonly carry multi-copy small plasmids. This study found that mobile genetic elements carrying antimicrobial resistance genes are capable of hijacking small plasmids. This study focused on aztreonam-avibactam (ATM-AVI) as this combination can be used to effectively counter almost all β-lactamases produced by bacteria, and has been recommended against carbapenem-resistant Enterobacterales. A clinical strain (085003) of carbapenem-resistant Escherichia coli was investigated, and mutants (085003R32 and 085003R512) able to grow under 32/4 and 512/4 mg/L of ATM-AVI were obtained as representatives of low- and high-level resistance, respectively, by induction. Comparative genomics showed that 085003R32 and 085003R512 had a single nucleotide mutation of β-lactamase gene bla(CMY-2), encoding a novel CMY with a Thr319Ile substitution, assigned 'CMY-2R'. Cloning and enzyme kinetics were used to verify that CMY-2R conferred ATM-AVI resistance by compromising binding of AVI and subsequent protection of ATM. Mechanisms for the discrepant resistance between 085003R32 and 085003R512 were investigated. Three tandem copies of bla(CMY-2R) were identified on a self-transmissible IncP1 plasmid of 085003R32 due to IS1294 misrecognizing its end terIS and rolling-circle replication. 085003R512 had only a single copy of bla(CMY-2R) on the IncP1 plasmid, but possessed anther bla(CMY-2R) on an already present 4-kb small plasmid. IS1294-mediated mobilization on to this multi-copy small plasmid increased the copy number of bla(CMY-2R) significantly, rendering higher resistance. This study shows that bacteria can employ multiple approaches to accommodate selection pressures imposed by exposure to varied concentrations of antimicrobial agents.202337769749
22380.9289Phosphoethanolamine Transferases as Drug Discovery Targets for Therapeutic Treatment of Multi-Drug Resistant Pathogenic Gram-Negative Bacteria. Antibiotic resistance caused by multidrug-resistant (MDR) bacteria is a major challenge to global public health. Polymyxins are increasingly being used as last-in-line antibiotics to treat MDR Gram-negative bacterial infections, but resistance development renders them ineffective for empirical therapy. The main mechanism that bacteria use to defend against polymyxins is to modify the lipid A headgroups of the outer membrane by adding phosphoethanolamine (PEA) moieties. In addition to lipid A modifying PEA transferases, Gram-negative bacteria possess PEA transferases that decorate proteins and glycans. This review provides a comprehensive overview of the function, structure, and mechanism of action of PEA transferases identified in pathogenic Gram-negative bacteria. It also summarizes the current drug development progress targeting this enzyme family, which could reverse antibiotic resistance to polymyxins to restore their utility in empiric therapy.202337760679
155690.9288Resistance to Colistin in Klebsiella Pneumoniae: A 4.0 Strain? The global rise of multidrug-resistant gram-negative bacteria represents an increasing threat to patient safety. From the first observation of a carbapenem-resistant gram-negative bacteria a global spread of extended-spectrum beta-lactamases and carbapenemases producing Klebsiella pneumoniae has been observed. Treatment options for multidrug-resistant K. pneumoniae are actually limited to combination therapy with some aminoglycosides, tigecycline and to older antimicrobial agents. Unfortunately, the prevalence of colistin-resistant and tigecycline-resistant K. pneumoniae is increasing globally. Infection due to colistin-resistant K. pneumoniae represents an independent risk factor for mortality. Resistance to colistin in K. pneumoniae may be multifactorial, as it is mediated by chromosomal genes or plasmids. The emergence of transmissible, plasmid-mediated colistin resistance is an alarming finding. The absence of new agents effective against resistant Gram-negative pathogens means that enhanced surveillance, compliance with infection prevention procedures, and antimicrobial stewardship programs will be required to limit the spread of colistin-resistant K. pneumoniae.201728626539
9050100.9286Cationic Polysaccharide Conjugates as Antibiotic Adjuvants Resensitize Multidrug-Resistant Bacteria and Prevent Resistance. In recent years, traditional antibiotic efficacy has rapidly diminished due to the advent of multidrug-resistant (MDR) bacteria, which poses severe threat to human life and globalized healthcare. Currently, the development cycle of new antibiotics cannot match the ongoing MDR infection crisis. Therefore, novel strategies are required to resensitize MDR bacteria to existing antibiotics. In this study, novel cationic polysaccharide conjugates Dextran-graft-poly(5-(1,2-dithiolan-3-yl)-N-(2-guanidinoethyl)pentanamide) (Dex-g-PSS(n) ) is synthesized using disulfide exchange polymerization. Critically, bacterial membranes and efflux pumps are disrupted by a sub-inhibitory concentration of Dex-g-PSS(30) , which enhances rifampicin (RIF) accumulation inside bacteria and restores its efficacy. Combined Dex-g-PSS(30) and RIF prevents bacterial resistance in bacteria cultured over 30 generations. Furthermore, Dex-g-PSS(30) restores RIF effectiveness, reduces inflammatory reactions in a pneumonia-induced mouse model, and exhibits excellent in vivo biological absorption and degradation capabilities. As an antibiotic adjuvant, Dex-g-PSS(30) provides a novel resensitizing strategy for RIF against MDR bacteria and bacterial resistance. This Dex-g-PSS(30) research provides a solid platform for future MDR applications.202235962720
5044110.9285Detection of Colistin Resistance in Salmonella enterica Using MALDIxin Test on the Routine MALDI Biotyper Sirius Mass Spectrometer. Resistance to polymyxins in most Gram-negative bacteria arises from chemical modifications to the lipid A portion of their lipopolysaccharide (LPS) mediated by chromosomally encoded mutations or the recently discovered plasmid-encoded mcr genes that have further complicated the landscape of colistin resistance. Currently, minimal inhibitory concentration (MIC) determination by broth microdilution, the gold standard for the detection of polymyxin resistance, is time consuming (24 h) and challenging to perform in clinical and veterinary laboratories. Here we present the use of the MALDIxin to detect colistin resistant Salmonella enterica using the MALDxin test on the routine matrix-assisted laser desorption ionization (MALDI) Biotyper Sirius system.202032582090
2498120.9285Emerging carbapenemases: a global perspective. The celestial rise in antibiotic resistance among Gram-negative bacteria has challenged both the scientific and pharmaceutical sectors. The hallmark of this general increase is the unbridled dissemination of carbapenem resistance genes, namely KPC, OXA and metallo-β-lactamase variants. In particular, the media attention given to the NDM-1 metallo-β-lactamase has highlighted the global consequences of human behaviour on spreading antibiotic resistance.201021129630
9808130.9285Understanding Recent Developments in Colistin Resistance: Mechanisms, Clinical Implications, and Future Perspectives. Colistin resistance, driven by chromosomal mutations and the spread of plasmid-mediated MCR genes, has emerged as a critical challenge in combating multidrug-resistant Gram-negative bacteria. This resistance compromises the efficacy of colistin, leading to higher treatment failure rates, prolonged hospitalizations, and increased mortality. Recent studies have highlighted key mechanisms, including lipid A modifications, that enable bacteria to evade colistin's effects. The global spread of MCR genes exacerbates the issue, underlining the need for improved diagnostics and rapid detection of resistant strains to prevent adverse patient outcomes. To combat this growing threat, a multifaceted approach is essential, involving enhanced antimicrobial stewardship, stricter infection control measures, and continued research into alternative therapies and diagnostic methods. Collaborative efforts from researchers, healthcare providers, policymakers, and the pharmaceutical industry are crucial to preserving colistin's effectiveness and mitigating the broader impact on public health.202541148650
2492140.9284Mobile Tigecycline Resistance: An Emerging Health Catastrophe Requiring Urgent One Health Global Intervention. Mobile tigecycline resistance (MTR) threatens the clinical efficacy of the salvage antibiotic, tigecycline (TIG) used in treating deadly infections in humans caused by superbugs (multidrug-, extensively drug-, and pandrug-resistant bacteria), including carbapenem- and colistin-resistant bacteria. Currently, non-mobile tet(X) and mobile plasmid-mediated transmissible tet(X) and resistance-nodulation-division (RND) efflux pump tmexCD-toprJ genes, conferring high-level TIG (HLT) resistance have been detected in humans, animals, and environmental ecosystems. Given the increasing rate of development and spread of plasmid-mediated resistance against the two last-resort antibiotics, colistin (COL) and TIG, there is a need to alert the global community on the emergence and spread of plasmid-mediated HLT resistance and the need for nations, especially developing countries, to increase their antimicrobial stewardship. Justifiably, MTR spread projects One Health ramifications and portends a monumental threat to global public and animal health, which could lead to outrageous health and economic impact due to limited options for therapy. To delve more into this very important subject matter, this current work will discuss why MTR is an emerging health catastrophe requiring urgent One Health global intervention, which has been constructed as follows: (a) antimicrobial activity of TIG; (b) mechanism of TIG resistance; (c) distribution, reservoirs, and traits of MTR gene-harboring isolates; (d) causes of MTR development; (e) possible MTR gene transfer mode and One Health implication; and (f) MTR spread and mitigating strategies.202235979498
9099150.9283Small molecule downregulation of PmrAB reverses lipid A modification and breaks colistin resistance. Infections caused by multi-drug resistant bacteria, particularly Gram-negative bacteria, are an ever-increasing problem. While the development of new antibiotics remains one option in the fight against bacteria that have become resistant to currently available antibiotics, an attractive alternative is the development of adjuvant therapeutics that restore the efficacy of existing antibiotics. We report a small molecule adjuvant that suppresses colistin resistance in multidrug resistant Acinetobacter baumannii and Klebsiella pneumoniae by interfering with the expression of a two-component system. The compound downregulates the pmrCAB operon and reverses phosphoethanolamine modification of lipid A responsible for colistin resistance. Furthermore, colistin-susceptible and colistin-resistant bacteria do not evolve resistance to combination treatment. This represents the first definitive example of a compound that breaks antibiotic resistance by directly modulating two-component system activity.201424131198
1533160.9283A Transferable IncC-IncX3 Hybrid Plasmid Cocarrying bla(NDM-4), tet(X), and tmexCD3-toprJ3 Confers Resistance to Carbapenem and Tigecycline. Tigecycline is a last-resort antimicrobial against carbapenemase-producing Enterobacterales (CPE). However, mobile tigecycline resistance genes, tet(X) and tmexCD-toprJ, have emerged in China and have spread possibly worldwide. Tet(X) family proteins function as tigecycline-inactivating enzymes, and TMexCD-TOprJ complexes function as efflux pumps for tigecycline. Here, to the best of our knowledge we report a CPE isolate harboring both emerging tigecycline resistance factors for the first time. A carbapenem- and tigecycline-resistant Klebsiella aerogenes strain, NUITM-VK5, was isolated from an urban drainage in Vietnam in 2021, and a plasmid, pNUITM-VK5_mdr, cocarrying tet(X) and tmexCD3-toprJ3 along with the carbapenemase gene bla(NDM-4) was identified in NUITM-VK5. pNUITM-VK5_mdr was transferred to Escherichia coli by conjugation and simultaneously conferred high-level resistance against multiple antimicrobials, including carbapenems and tigecycline. An efflux pump inhibitor reduced TMexCD3-TOprJ3-mediated tigecycline resistance, suggesting that both tigecycline resistance factors independently and additively contribute to the high-level resistance. The plasmid had the IncX3 and IncC replicons and was estimated to be a hybrid of plasmids with different backbones. Unlike IncX3 plasmids, IncC plasmids are stably maintained in an extremely broad range of bacterial hosts in humans, animals, and the environment. Thus, the future global spread of multidrug resistance plasmids such as pNUITM-VK5_mdr poses a public health crisis. IMPORTANCE Tigecycline is important as a last-resort antimicrobial and effective against antimicrobial-resistant bacteria, such as carbapenem-producing Enterobacterales (CPE), whose infections are difficult to treat with antimicrobials. Since 2019, mobile tigecycline resistance genes, tet(X) and tmexCD-toprJ, and their variants have been reported mainly from China, and it has become important to understand their epidemiological situation and detailed genetic mechanisms. In this study, we identified a bacterial isolate coharboring tet(X) and tmexCD-toprJ on the same plasmid. A Klebsiella aerogenes isolate in Vietnam carried both these tigecycline resistance genes on a transferable plasmid leading to high-level resistance to multiple clinically important antimicrobials, including carbapenem and tigecycline, and could actually transfer the plasmid to other bacteria. The spread of such a multidrug resistance plasmid among bacterial pathogens should be of great concern because there are few antimicrobials to combat bacteria that have acquired the plasmid.202134346701
2517170.9283The Epidemiology of Carbapenem-Resistant Enterobacteriaceae: The Impact and Evolution of a Global Menace. Carbapenem-resistant Enterobacteriaceae (CRE) are a serious public health threat. Infections due to these organisms are associated with significant morbidity and mortality. Mechanisms of drug resistance in gram-negative bacteria (GNB) are numerous; β-lactamase genes carried on mobile genetic elements are a key mechanism for the rapid spread of antibiotic-resistant GNB worldwide. Transmissible carbapenem-resistance in Enterobacteriaceae has been recognized for the last 2 decades, but global dissemination of carbapenemase-producing Enterobacteriaceae (CPE) is a more recent problem that, once initiated, has been occurring at an alarming pace. In this article, we discuss the evolution of CRE, with a focus on the epidemiology of the CPE pandemic; review risk factors for colonization and infection with the most common transmissible CPE worldwide, Klebsiella pneumoniae carbapenemase-producing K. pneumoniae; and present strategies used to halt the striking spread of these deadly pathogens.201728375512
1555180.9283Carbapenemase-producing Gram-negative bacteria: current epidemics, antimicrobial susceptibility and treatment options. Carbapenemases, with versatile hydrolytic capacity against β-lactams, are now an important cause of resistance of Gram-negative bacteria. The genes encoding for the acquired carbapenemases are associated with a high potential for dissemination. In addition, infections due to Gram-negative bacteria with acquired carbapenemase production would lead to high clinical mortality rates. Of the acquired carbapenemases, Klebsiella pneumoniae carbapenemase (Ambler class A), Verona integron-encoded metallo-β-lactamase (Ambler class B), New Delhi metallo-β-lactamase (Ambler class B) and many OXA enzymes (OXA-23-like, OXA-24-like, OXA-48-like, OXA-58-like, class D) are considered to be responsible for the worldwide resistance epidemics. As compared with monotherapy with colistin or tigecycline, combination therapy has been shown to effectively lower case-fatality rates. However, development of new antibiotics is crucial in the present pandrug-resistant era.201525812463
1549190.9283Evaluation of the Inter- and Intrahospital Spread of Multidrug Resistant Gram-Negative Bacteria in Lithuanian Hospitals. Spread of multidrug-resistant pathogenic bacteria became one of the greatest threats in healthcare worldwide. It is generally accepted that both inter- and intrahospital transmissions of these bacteria contribute significantly to this problem. The purpose of the current study was the evaluation of the inter- and intrahospital spread of multidrug resistant Gram-negative pathogenic bacteria in Lithuania. Clinical isolates of Acinetobacter sp., Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa were subjected for the screening for extended spectrum β-lactamase, carbapenemase, as well as plasmid-mediated AmpC β-lactamase genes. BOX-PCR genotyping was used for the genotyping of these isolates. Our results show that all four pathogens are involved in the intra- and/or interhospital dissemination between the Lithuanian healthcare institutions. The level of transmissions differed between pathogens, and the worst situation was detected for Acinetobacter sp. followed by E. coli. In almost all cases, transmissible strains had at least one gene conferring β-lactam resistance, thereby contributing to the dissemination of the resistance determinants in and between Lithuanian hospitals. Our study clearly demonstrated that immediate actions, more effective strategy, and surveillance are needed to confine and prevent further spread of multidrug resistant Gram-negative pathogenic bacteria in Lithuanian healthcare institutions.201930339100