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Singh S, Singh S, Trivedi M, Dwivedi M. An insight into MDR Acinetobacter baumannii infection and its pathogenesis: Potential therapeutic targets and challenges. Microb Pathog 2024; 192:106674. [PMID: 38714263 DOI: 10.1016/j.micpath.2024.106674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 04/22/2024] [Accepted: 05/01/2024] [Indexed: 05/09/2024]
Abstract
Acinetobacter baumannii is observed as a common species of Gram-negative bacteria that exist in soil and water. Despite being accepted as a typical component of human skin flora, it has become an important opportunistic pathogen, especially in healthcare settings. The pathogenicity of A. baumannii is attributed to its virulence factors, which include adhesins, pili, lipopolysaccharides, outer membrane proteins, iron uptake systems, autotransporter, secretion systems, phospholipases etc. These elements provide the bacterium the ability to cling to and penetrate host cells, get past the host immune system, and destroy tissue. Its infection is a major contributor to human pathophysiological conditions including pneumonia, bloodstream infections, urinary tract infections, and surgical site infections. It is challenging to treat infections brought on by this pathogen since this bacterium has evolved to withstand numerous drugs and further emergence of drug-resistant A. baumannii results in higher rates of morbidity and mortality. The long-term survival of this bacterium on surfaces of medical supplies and hospital furniture facilitates its frequent spread in humans from one habitat to another. There is a need for urgent investigations to find effective drug targets for A. baumannii as well as designing novel drugs to reduce the survival and spread of infection. In the current review, we represent the specific features, pathogenesis, and molecular intricacies of crucial drug targets of A. baumannii. This would also assist in proposing strategies and alternative therapies for the prevention and treatment of A. baumannii infections and their spread.
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Affiliation(s)
- Sukriti Singh
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Lucknow, 226028, India
| | - Sushmita Singh
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Lucknow, 226028, India
| | - Mala Trivedi
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Lucknow, 226028, India
| | - Manish Dwivedi
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Lucknow, 226028, India; Research Cell, Amity University Uttar Pradesh, Lucknow, 226028, India.
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2
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Ostroumova OS, Efimova SS. Lipid-Centric Approaches in Combating Infectious Diseases: Antibacterials, Antifungals and Antivirals with Lipid-Associated Mechanisms of Action. Antibiotics (Basel) 2023; 12:1716. [PMID: 38136750 PMCID: PMC10741038 DOI: 10.3390/antibiotics12121716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/05/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023] Open
Abstract
One of the global challenges of the 21st century is the increase in mortality from infectious diseases against the backdrop of the spread of antibiotic-resistant pathogenic microorganisms. In this regard, it is worth targeting antibacterials towards the membranes of pathogens that are quite conservative and not amenable to elimination. This review is an attempt to critically analyze the possibilities of targeting antimicrobial agents towards enzymes involved in pathogen lipid biosynthesis or towards bacterial, fungal, and viral lipid membranes, to increase the permeability via pore formation and to modulate the membranes' properties in a manner that makes them incompatible with the pathogen's life cycle. This review discusses the advantages and disadvantages of each approach in the search for highly effective but nontoxic antimicrobial agents. Examples of compounds with a proven molecular mechanism of action are presented, and the types of the most promising pharmacophores for further research and the improvement of the characteristics of antibiotics are discussed. The strategies that pathogens use for survival in terms of modulating the lipid composition and physical properties of the membrane, achieving a balance between resistance to antibiotics and the ability to facilitate all necessary transport and signaling processes, are also considered.
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Affiliation(s)
- Olga S. Ostroumova
- Laboratory of Membrane and Ion Channel Modeling, Institute of Cytology, Russian Academy of Sciences, Tikhoretsky Ave. 4, St. Petersburg 194064, Russia;
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3
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Aldali JA. Acinetobacter baumannii: A multidrug-resistant pathogen, has emerged in Saudi Arabia. Saudi Med J 2023; 44:732-744. [PMID: 37582561 PMCID: PMC10425629 DOI: 10.15537/smj.2023.44.8.20230194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/17/2023] Open
Abstract
A significant opportunistic pathogen, Acinetobacter baumannii (A. baumannii) has evolved mechanisms of resistance to a wide variety of antimicrobials, including carbapenems. In this article, we assessed the prevalence, risk factors, antimicrobial sensitivity, and resistance mechanisms among A. baumannii in several locations in Saudi Arabia. Hospital-acquired infections caused by A. baumannii were prevalent in the country due to a variety of reasons, such as the high number of critically ill patients, the frequency of gastrointestinal colonization, and the widespread use of antimicrobial medications. There has been an increase in the frequency of A. baumannii strains that are resistant to several antimicrobials, including carbapenems. Hospitals are a breeding ground for multidrug-resistant A. baumannii due to the widespread use of broad-spectrum antibiotics, the potential for patient-to-patient transmission of the bacteria, the high risk of infection during invasive intensive care unit procedures, and the high frequency with which diabetic and cancer patients in hospitals undergo invasive diagnostic and therapeutic procedures. Combinations of colistin and tigecycline with carbapenems or other antibiotics remain the best treatment option and are relatively safe to treat patients with multidrug resistance (MDR) A. baumannii infections, despite the rising incidence of resistance to these drugs observed in many hospitals. The prevalence of multidrug-resistant A. baumannii in Saudi hospitals calls for in-depth research into the underlying molecular mechanisms of multidrug resistance. In addition, a better understanding of A. baumannii resistance patterns and the establishment of a treatment protocol to reduce the infection burden in Saudi Arabia could benefit from the implementation of a local antibiogram database in tandem with a national antimicrobial stewardship and infection prevention program.
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Affiliation(s)
- Jehad A. Aldali
- From the Department of Pathology, College of Medicine, Imam Mohammad Ibn Saud Islamic University, Riyadh, Kingdom of Saudi Arabia.
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4
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Green KD, Thamban Chandrika N, Vu LY, Pang AH, Tsodikov OV, Garneau-Tsodikova S. Aromatic hydrazides: A potential solution for Acinetobacter baumannii infections. Eur J Med Chem 2023; 249:115165. [PMID: 36739749 PMCID: PMC9974912 DOI: 10.1016/j.ejmech.2023.115165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 01/16/2023] [Accepted: 01/18/2023] [Indexed: 01/31/2023]
Abstract
The emergence of multidrug-resistant bacteria and the poor efficacy of available antibiotics against these infections have led to the urgent need for novel antibiotics. Acinetobacter baumannii is one of high-priority pathogens due to its ability to mount resistance to different classes of antibiotics. In an effort to provide novel agents in the fight against infections caused by A. baumannii, we synthesized a series of 46 aromatic hydrazides as potential treatments. In this series, 34 compounds were found to be low- to sub-μM inhibitors of A. baumannii growth, with MIC values in the range of 8 μg/mL to ≤0.125 μg/mL against a broad set of multidrug-resistant clinical isolates. These compounds were not highly active against other bacteria. We showed that one of the most potent compounds, 3e, was bacteriostatic and inhibitory to biofilm formation, although it did not disrupt the preformed biofilm. Additionally, we found that these compounds lacked mammalian cytotoxicity. The high antibacterial potency and the lack of mammalian cytotoxicity make these compounds a promising lead series for development of a novel selective anti-A. baumannii antibiotic.
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Affiliation(s)
- Keith D Green
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536-0596, USA
| | - Nishad Thamban Chandrika
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536-0596, USA
| | - Loan Y Vu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536-0596, USA
| | - Allan H Pang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536-0596, USA
| | - Oleg V Tsodikov
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536-0596, USA
| | - Sylvie Garneau-Tsodikova
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY, 40536-0596, USA.
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5
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Tan YC, Lahiri C. Promising Acinetobacter baumannii Vaccine Candidates and Drug Targets in Recent Years. Front Immunol 2022; 13:900509. [PMID: 35720310 PMCID: PMC9204607 DOI: 10.3389/fimmu.2022.900509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Accepted: 04/26/2022] [Indexed: 12/14/2022] Open
Abstract
In parallel to the uncontrolled use of antibiotics, the emergence of multidrug-resistant bacteria, like Acinetobacter baumannii, has posed a severe threat. A. baumannii predominates in the nosocomial setting due to its ability to persist in hospitals and survive antibiotic treatment, thereby eventually leading to an increasing prevalence and mortality due to its infection. With the increasing spectra of drug resistance and the incessant collapse of newly discovered antibiotics, new therapeutic countermeasures have been in high demand. Hence, recent research has shown favouritism towards the long-term solution of designing vaccines. Therefore, being a realistic alternative strategy to combat this pathogen, anti-A. Baumannii vaccines research has continued unearthing various antigens with variable results over the last decade. Again, other approaches, including pan-genomics, subtractive proteomics, and reverse vaccination strategies, have shown promise for identifying promiscuous core vaccine candidates that resulted in chimeric vaccine constructs. In addition, the integration of basic knowledge of the pathobiology of this drug-resistant bacteria has also facilitated the development of effective multiantigen vaccines. As opposed to the conventional trial-and-error approach, incorporating the in silico methods in recent studies, particularly network analysis, has manifested a great promise in unearthing novel vaccine candidates from the A. baumannii proteome. Some studies have used multiple A. baumannii data sources to build the co-functional networks and analyze them by k-shell decomposition. Additionally, Whole Genomic Protein Interactome (GPIN) analysis has utilized a rational approach for identifying essential proteins and presenting them as vaccines effective enough to combat the deadly pathogenic threats posed by A. baumannii. Others have identified multiple immune nodes using network-based centrality measurements for synergistic antigen combinations for different vaccination strategies. Protein-protein interactions have also been inferenced utilizing structural approaches, such as molecular docking and molecular dynamics simulation. Similar workflows and technologies were employed to unveil novel A. baumannii drug targets, with a similar trend in the increasing influx of in silico techniques. This review integrates the latest knowledge on the development of A. baumannii vaccines while highlighting the in silico methods as the future of such exploratory research. In parallel, we also briefly summarize recent advancements in A. baumannii drug target research.
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Affiliation(s)
- Yong Chiang Tan
- School of Postgraduate Studies, International Medical University, Kuala Lumpur, Malaysia
| | - Chandrajit Lahiri
- Department of Biological Sciences, Sunway University, Petaling Jaya, Malaysia
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6
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Insights into Acinetobacter baumannii fatty acid synthesis 3-oxoacyl-ACP reductases. Sci Rep 2021; 11:7050. [PMID: 33782435 PMCID: PMC8007833 DOI: 10.1038/s41598-021-86400-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 03/08/2021] [Indexed: 11/08/2022] Open
Abstract
Treatments for 'superbug' infections are the focus for innovative research, as drug resistance threatens human health and medical practices globally. In particular, Acinetobacter baumannii (Ab) infections are repeatedly reported as difficult to treat due to increasing antibiotic resistance. Therefore, there is increasing need to identify novel targets in the development of different antimicrobials. Of particular interest is fatty acid synthesis, vital for the formation of phospholipids, lipopolysaccharides/lipooligosaccharides, and lipoproteins of Gram-negative envelopes. The bacterial type II fatty acid synthesis (FASII) pathway is an attractive target for the development of inhibitors and is particularly favourable due to the differences from mammalian type I fatty acid synthesis. Discrete enzymes in this pathway include two reductase enzymes: 3-oxoacyl-acyl carrier protein (ACP) reductase (FabG) and enoyl-ACP reductase (FabI). Here, we investigate annotated FabG homologs, finding a low-molecular weight 3-oxoacyl-ACP reductase, as the most likely FASII FabG candidate, and high-molecular weight 3-oxoacyl-ACP reductase (HMwFabG), showing differences in structure and coenzyme preference. To date, this is the second bacterial high-molecular weight FabG structurally characterized, following FabG4 from Mycobacterium. We show that ΔAbHMwfabG is impaired for growth in nutrient rich media and pellicle formation. We also modelled a third 3-oxoacyl-ACP reductase, which we annotated as AbSDR. Despite containing residues for catalysis and the ACP coordinating motif, biochemical analyses showed limited activity against an acetoacetyl-CoA substrate in vitro. Inhibitors designed to target FabG proteins and thus prevent fatty acid synthesis may provide a platform for use against multidrug-resistant pathogens including A. baumannii.
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7
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Rana P, Ghouse SM, Akunuri R, Madhavi YV, Chopra S, Nanduri S. FabI (enoyl acyl carrier protein reductase) - A potential broad spectrum therapeutic target and its inhibitors. Eur J Med Chem 2020; 208:112757. [PMID: 32883635 DOI: 10.1016/j.ejmech.2020.112757] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 07/30/2020] [Accepted: 08/11/2020] [Indexed: 12/11/2022]
Abstract
Development of new anti-bacterial agents acting upon underexploited targets and thus evading known mechanisms of resistance is the need of the hour. The highly conserved and distinct bacterial fatty acid biosynthesis pathway (FAS-II), presents a validated and yet relatively underexploited target for drug discovery. FabI and its isoforms (FabL, FabK, FabV and InhA) are essential enoyl-ACP reductases present in several microorganisms. In addition, the components of the FAS-II pathway are distinct from the multi-enzyme FAS-I complex found in mammals. Thus, inhibition of FabI and its isoforms is anticipated to result in broad-spectrum antibacterial activity. Several research groups from industry and academic laboratories have devoted significant efforts to develop effective FabI-targeting antibiotics, which are currently in various stages of clinical development for the treatment of multi-drug resistant bacterial infections. This review summarizes all the natural as well as synthetic inhibitors of gram-positive and gram-negative enoyl ACP reductases (FabI). The knowledge of the reported inhibitors can aid in the development of broad-spectrum antibacterials specifically targeting FabI enzymes from S. aureus, S. epidermidis, B. anthracis, B. cereus, E. coli, P. aeruginosa, P. falciparum and M. tuberculosis.
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Affiliation(s)
- Preeti Rana
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, 500 037, India
| | - Shaik Mahammad Ghouse
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, 500 037, India
| | - Ravikumar Akunuri
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, 500 037, India
| | - Y V Madhavi
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, 500 037, India
| | - Sidharth Chopra
- Division of Microbiology, CSIR-Central Drug Research Institute, Sitapur Road, Sector 10, Janakipuram Extension, Lucknow, 226 031, Uttar Pradesh, India.
| | - Srinivas Nanduri
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, 500 037, India.
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8
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Cushnie TPT, Cushnie B, Echeverría J, Fowsantear W, Thammawat S, Dodgson JLA, Law S, Clow SM. Bioprospecting for Antibacterial Drugs: a Multidisciplinary Perspective on Natural Product Source Material, Bioassay Selection and Avoidable Pitfalls. Pharm Res 2020; 37:125. [PMID: 32529587 DOI: 10.1007/s11095-020-02849-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 05/30/2020] [Indexed: 12/12/2022]
Abstract
Bioprospecting is the exploration, extraction and screening of biological material and sometimes indigenous knowledge to discover and develop new drugs and other products. Most antibiotics in current clinical use (eg. β-lactams, aminoglycosides, tetracyclines, macrolides) were discovered using this approach, and there are strong arguments to reprioritize bioprospecting over other strategies in the search for new antibacterial drugs. Academic institutions should be well positioned to lead the early stages of these efforts given their many thousands of locations globally and because they are not constrained by the same commercial considerations as industry. University groups can lack the full complement of knowledge and skills needed though (eg. how to tailor screening strategy to biological source material). In this article, we review three key aspects of the bioprospecting literature (source material and in vitro antibacterial and toxicity testing) and present an integrated multidisciplinary perspective on (a) source material selection, (b) legal, taxonomic and other issues related to source material, (c) cultivation methods, (d) bioassay selection, (e) technical standards available, (f) extract/compound dissolution, (g) use of minimum inhibitory concentration and selectivity index values to identify progressible extracts and compounds, and (h) avoidable pitfalls. The review closes with recommendations for future study design and information on subsequent steps in the bioprospecting process.
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Affiliation(s)
- T P Tim Cushnie
- Faculty of Medicine, Mahasarakham University, 269 Nakornsawan Road, Mahasarakham, 44000, Thailand.
| | - Benjamart Cushnie
- Faculty of Pharmacy, Mahasarakham University, Kantarawichai, Thailand
| | - Javier Echeverría
- Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Winita Fowsantear
- Faculty of Medicine, Mahasarakham University, 269 Nakornsawan Road, Mahasarakham, 44000, Thailand
| | - Sutthiwan Thammawat
- Faculty of Medicine, Mahasarakham University, 269 Nakornsawan Road, Mahasarakham, 44000, Thailand
| | | | - Samantha Law
- National Collection of Industrial, Food and Marine Bacteria (NCIMB) Ltd, Aberdeen, UK
| | - Simon M Clow
- PMI BioPharma Solutions LLC, Nashville, Tennessee, USA
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9
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Johnson ME, Fung LWM. Structural approaches to pathway-specific antimicrobial agents. Transl Res 2020; 220:114-121. [PMID: 32105648 PMCID: PMC7293926 DOI: 10.1016/j.trsl.2020.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 01/31/2020] [Accepted: 02/03/2020] [Indexed: 10/25/2022]
Abstract
This perspective provides an overview of the evolution of antibiotic discovery from a largely phenotypic-based effort, through an intensive structure-based design focus, to a more holistic approach today. The current focus on antibiotic development incorporates assay and discovery conditions that replicate the host environment as much as feasible. They also incorporate several strategies, including target identification and validation within the whole cell environment, a variety of target deconvolution methods, and continued refinement of structure-based design approaches.
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Affiliation(s)
- Michael E Johnson
- Department of Pharmaceutical Sciences, Center for Biomolecular Sciences, University of Illinois at Chicago, Chicago, Illinois.
| | - Leslie W-M Fung
- Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois.
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10
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da Rosa TF, Coelho SS, Foletto VS, Bottega A, Serafin MB, Machado CDS, Franco LN, de Paula BR, Hörner R. Alternatives for the treatment of infections caused by ESKAPE pathogens. J Clin Pharm Ther 2020; 45:863-873. [PMID: 32339305 DOI: 10.1111/jcpt.13149] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 02/11/2020] [Accepted: 04/03/2020] [Indexed: 12/21/2022]
Abstract
WHAT IS KNOWN AND OBJECTIVE The widespread use of antibiotics as therapeutic agents caused an increase of multidrug resistant bacteria (MDR) appearance. Regarding MDRs, we highlight the Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp.., which are the ESKAPE group. COMMENT New treatment alternatives for infections caused by ESKAPE are under current scientific research. The main suggestions are the use of actinomycetes that produce promising substances with antibiotic activity, the synergistic effect between antimicrobials and peptides, photoinactivation, peptide rich in cationic histidine, association of new antimicrobials; besides the repositioning of drugs already approved for the treatment of other diseases. WHAT IS NEW AND CONCLUSION These selected studies showed that researchers from many countries are focused on the development of effective alternative strategies for the treatment of infections caused by these microorganisms.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Rosmari Hörner
- Department of Clinical and Toxicological Analysis, Federal University of Santa Maria, Santa Maria, Brazil
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11
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Rao NK, Nataraj V, Ravi M, Panchariya L, Palai K, Talapati SR, Lakshminarasimhan A, Ramachandra M, Antony T. Ternary complex formation of AFN-1252 with Acinetobacter baumannii FabI and NADH: Crystallographic and biochemical studies. Chem Biol Drug Des 2020; 96:704-713. [PMID: 32227402 DOI: 10.1111/cbdd.13686] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 01/08/2020] [Accepted: 01/25/2020] [Indexed: 01/22/2023]
Abstract
Acinetobacter baumannii is an opportunistic Gram-negative bacterial pathogen, associated mostly with hospital-acquired infections. The emergence of drug resistance strains made it necessary to explore new pathways for the development of more effective antibiotics. Enoyl CoA reductase (FabI), a key enzyme in the fatty acid biosynthesis (FAS) pathway, has emerged as a potential target for antibacterial drug development. Earlier reports show that the lead SaFabI inhibitor AFN-1252 can inhibit FabI from other organisms including Escherichia coli and Burkholderia pseudomallei, but with differential potency. In the present work, we show that AFN-1252 is a moderate inhibitor of AbFabI with an IC50 of 216 nM. AFN-1252 stabilized AbFabI with a 4.2°C increase in the melting temperature (Tm ) and, interestingly, the stabilization effect was significantly increased in presence of the cofactor NADH (∆Tm = 17°C), suggesting the formation of a ternary complex AbFabI: AFN-1252: NADH. X-ray crystallography studies of AbFabI co-crystalized with AFN-1252 and NADH confirmed the ternary complex formation. The critical interactions of AFN-1252 with AbFabI and NADH identified from the co-crystal structure may facilitate the design and development of new drugs against A. baumannii infections by targeting the FAS pathway.
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Affiliation(s)
| | | | - Mohan Ravi
- Aurigene Discovery Technologies Ltd, Bangalore, India
| | - Love Panchariya
- International Center for Genetic Engineering and Biotechnology, New Delhi, India
| | | | | | | | | | - Thomas Antony
- Aurigene Discovery Technologies Ltd, Bangalore, India
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12
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A Whole-Cell Screen Identifies Small Bioactives That Synergize with Polymyxin and Exhibit Antimicrobial Activities against Multidrug-Resistant Bacteria. Antimicrob Agents Chemother 2020; 64:AAC.01677-19. [PMID: 31844003 DOI: 10.1128/aac.01677-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 12/05/2019] [Indexed: 12/19/2022] Open
Abstract
The threat of diminished antibiotic discovery has global health care in crisis. In the United States, it is estimated each year that over 2 million bacterial infections are resistant to first-line antibiotic treatments and cost in excess of 20 billion dollars. Many of these cases result from infection with the ESKAPE pathogens ( Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species), which are multidrug-resistant bacteria that often cause community- and hospital-acquired infections in both healthy and immunocompromised patients. Physicians have turned to last-resort antibiotics like polymyxins to tackle these pathogens, and as a consequence, polymyxin resistance has emerged and is spreading. Barring the discovery of new antibiotics, another route to successfully mitigate polymyxin resistance is to identify compounds that can complement the existing arsenal of antibiotics. We recently designed and performed a large-scale robotic screen to identify 43 bioactive compounds that act synergistically with polymyxin B to inhibit the growth of polymyxin-resistant Escherichia coli Of these 43 compounds, 5 lead compounds were identified and characterized using various Gram-negative bacterial organisms to better assess their synergistic activity with polymyxin. Several of these compounds reduce polymyxin to an MIC of <2 μg/ml against polymyxin-resistant and polymyxin-heteroresistant Gram-negative pathogens. Likewise, four of these compounds exhibit antimicrobial activity against Gram-positive bacteria, one of which rapidly eradicated methicillin-resistant Staphylococcus aureus We present multiple first-generation (i.e., not yet optimized) compounds that warrant further investigation and optimization, since they can act both synergistically with polymyxin and also as lone antimicrobials for combating ESKAPE pathogens.
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13
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Tillery LM, Barrett KF, Dranow DM, Craig J, Shek R, Chun I, Barrett LK, Phan IQ, Subramanian S, Abendroth J, Lorimer DD, Edwards TE, Van Voorhis WC. Toward a structome of Acinetobacter baumannii drug targets. Protein Sci 2020; 29:789-802. [PMID: 31930600 DOI: 10.1002/pro.3826] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 01/06/2020] [Accepted: 01/08/2020] [Indexed: 12/13/2022]
Abstract
Acinetobacter baumannii is well known for causing hospital-associated infections due in part to its intrinsic antibiotic resistance as well as its ability to remain viable on surfaces and resist cleaning agents. In a previous publication, A. baumannii strain AB5075 was studied by transposon mutagenesis and 438 essential gene candidates for growth on rich-medium were identified. The Seattle Structural Genomics Center for Infectious Disease entered 342 of these candidate essential genes into our pipeline for structure determination, in which 306 were successfully cloned into expression vectors, 192 were detectably expressed, 165 screened as soluble, 121 were purified, 52 crystalized, 30 provided diffraction data, and 29 structures were deposited in the Protein Data Bank. Here, we report these structures, compare them with human orthologs where applicable, and discuss their potential as drug targets for antibiotic development against A. baumannii.
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Affiliation(s)
- Logan M Tillery
- Department of Medicine, Division of Allergy and Infectious Disease, Center for Emerging and Re-emerging Infectious Disease (CERID), University of Washington, Seattle, Washington.,Seattle Structural Genomics Center for Infectious Disease, Seattle, Washington
| | - Kayleigh F Barrett
- Department of Medicine, Division of Allergy and Infectious Disease, Center for Emerging and Re-emerging Infectious Disease (CERID), University of Washington, Seattle, Washington.,Seattle Structural Genomics Center for Infectious Disease, Seattle, Washington
| | - David M Dranow
- Seattle Structural Genomics Center for Infectious Disease, Seattle, Washington.,UCB Pharma, Bainbridge Island, Washington
| | - Justin Craig
- Department of Medicine, Division of Allergy and Infectious Disease, Center for Emerging and Re-emerging Infectious Disease (CERID), University of Washington, Seattle, Washington.,Seattle Structural Genomics Center for Infectious Disease, Seattle, Washington
| | - Roger Shek
- Department of Medicine, Division of Allergy and Infectious Disease, Center for Emerging and Re-emerging Infectious Disease (CERID), University of Washington, Seattle, Washington.,Seattle Structural Genomics Center for Infectious Disease, Seattle, Washington
| | - Ian Chun
- Department of Medicine, Division of Allergy and Infectious Disease, Center for Emerging and Re-emerging Infectious Disease (CERID), University of Washington, Seattle, Washington.,Seattle Structural Genomics Center for Infectious Disease, Seattle, Washington
| | - Lynn K Barrett
- Department of Medicine, Division of Allergy and Infectious Disease, Center for Emerging and Re-emerging Infectious Disease (CERID), University of Washington, Seattle, Washington.,Seattle Structural Genomics Center for Infectious Disease, Seattle, Washington
| | - Isabelle Q Phan
- Seattle Structural Genomics Center for Infectious Disease, Seattle, Washington.,Seattle Children's Research Institute, Seattle, Washington
| | - Sandhya Subramanian
- Seattle Structural Genomics Center for Infectious Disease, Seattle, Washington.,Seattle Children's Research Institute, Seattle, Washington
| | - Jan Abendroth
- Seattle Structural Genomics Center for Infectious Disease, Seattle, Washington.,UCB Pharma, Bainbridge Island, Washington
| | - Donald D Lorimer
- Seattle Structural Genomics Center for Infectious Disease, Seattle, Washington.,UCB Pharma, Bainbridge Island, Washington
| | - Thomas E Edwards
- Seattle Structural Genomics Center for Infectious Disease, Seattle, Washington.,UCB Pharma, Bainbridge Island, Washington
| | - Wesley C Van Voorhis
- Department of Medicine, Division of Allergy and Infectious Disease, Center for Emerging and Re-emerging Infectious Disease (CERID), University of Washington, Seattle, Washington.,Seattle Structural Genomics Center for Infectious Disease, Seattle, Washington
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14
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Maltarollo VG. Classification of Staphylococcus Aureus FabI Inhibitors by Machine Learning Techniques. ACTA ACUST UNITED AC 2019. [DOI: 10.4018/ijqspr.2019100101] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Enoyl-acyl carrier protein reductase (FabI) is a key enzyme in the fatty acid metabolism of gram-positive bacteria and is considered a potential target for new antibacterial drugs development. Indeed, triclosan is a widely employed antibacterial and AFN-1252 is currently under phase-II clinical trials, both are known as FabI inhibitors. Nowadays, there is an urgent need for new drug discovery due to increasing antibacterial resistance. In the present study, classification models using machine learning techniques were generated to distinguish SaFabI inhibitors from non-inhibitors successfully (e.g., Mathews correlation coefficient values equal to 0.837 and 0.789 calculated with internal and external validations). The interpretation of a selected model indicates that larger compounds, number of N atoms and the distance between central amide and naphthyridinone ring are important to biological activity, corroborating previous studies. Therefore, these obtained information and generated models can be useful for design/discovery of novel bioactive ligands as potential antibacterial agents.
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15
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Antibacterial and Antibiofilm Activity and Mode of Action of Magainin 2 against Drug-Resistant Acinetobacter baumannii. Int J Mol Sci 2018; 19:ijms19103041. [PMID: 30301180 PMCID: PMC6213043 DOI: 10.3390/ijms19103041] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 09/28/2018] [Accepted: 09/28/2018] [Indexed: 02/06/2023] Open
Abstract
Antimicrobial peptides (AMPs) are promising therapeutic agents for treating antibiotic-resistant bacterial infections. Previous studies showed that magainin 2 (isolated from African clawed fogs Xenopus laevis) has antimicrobial activity against gram-positive and gram-negative bacteria. The present study was conducted to investigate the antibacterial activity of magainin 2 against Acinetobacter baumannii. Magainin 2 showed excellent antibacterial activity against A. baumannii strains and high stability at physiological salt concentrations. This peptide was not cytotoxic towards HaCaT cells and showed no hemolytic activity. Biofilm inhibition and elimination were significantly induced in all A. baumannii strains exposed to magainin 2. We confirmed the mechanism of magainin 2 on the bacterial outer and inner membranes. Collectively, these results suggest that magainin 2 is an effective antimicrobial and antibiofilm agent against A. baumannii strains.
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