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Mireles NA, Malla CF, Tavío MM. Cinnamaldehyde and baicalin reverse colistin resistance in Enterobacterales and Acinetobacter baumannii strains. Eur J Clin Microbiol Infect Dis 2024:10.1007/s10096-024-04884-x. [PMID: 39066966 DOI: 10.1007/s10096-024-04884-x] [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: 12/04/2023] [Accepted: 06/22/2024] [Indexed: 07/30/2024]
Abstract
PURPOSE Colistin is used as a last resort antibiotic against infections caused by multidrug-resistant gram-negative bacteria, especially carbapenem-resistant bacteria. However, colistin-resistance in clinical isolates is becoming more prevalent. Cinnamaldehyde and baicalin, which are the major active constituents of Cinnamomum and Scutellaria, have been reported to exhibit antibacterial properties. The aim of this study was to evaluate the capacity of cinnamaldehyde and baicalin to enhance the antibiotic activity of colistin in Enterobacterales and Acinetobacter baumannii strains. METHODS The MICs of colistin were determined with and without fixed concentrations of cinnamaldehyde and baicalin by the broth microdilution method. The FIC indices were also calculated. In addition, time-kill assays were performed with colistin alone and in combination with cinnamaldehyde and baicalin to determine the bactericidal action of the combinations. Similarly, the effects of L-arginine, L-glutamic acid and sucrose on the MICs of colistin combined with cinnamaldehyde and baicalin were studied to evaluate the possible effects of these compounds on the charge of the bacterial cell- wall. RESULTS At nontoxic concentrations, cinnamaldehyde and baicalin partially or fully reversed resistance to colistin in Enterobacterales and A. baumannii. The combinations of the two compounds with colistin had bactericidal or synergistic effects on the most resistant strains. The ability of these agents to reverse colistin resistance could be associated with bacterial cell wall damage and increased permeability. CONCLUSION Cinnamaldehyde and baicalin are good adjuvants for the antibiotic colistin against Enterobacterales- and A. baumannii-resistant strains.
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Affiliation(s)
- Natalia A Mireles
- Microbiology, Clinical Science Department, Faculty of Health Sciences, Universidad de Las Palmas de Gran Canaria, Paseo Blas Cabrera Felipe s/n, Las Palmas de Gran Canaria, 35016, Spain
- Medical Oncology, Josep Trueta University Hospital of Girona, Girona, 17007, Spain
| | - Cristina F Malla
- Microbiology, Clinical Science Department, Faculty of Health Sciences, Universidad de Las Palmas de Gran Canaria, Paseo Blas Cabrera Felipe s/n, Las Palmas de Gran Canaria, 35016, Spain
| | - María M Tavío
- Microbiology, Clinical Science Department, Faculty of Health Sciences, Universidad de Las Palmas de Gran Canaria, Paseo Blas Cabrera Felipe s/n, Las Palmas de Gran Canaria, 35016, Spain.
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2
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Ceres K, Zehr JD, Murrell C, Millet JK, Sun Q, McQueary HC, Horton A, Cazer C, Sams K, Reboul G, Andreopoulos WB, Mitchell PK, Anderson R, Franklin-Guild R, Cronk BD, Stanhope BJ, Burbick CR, Wolking R, Peak L, Zhang Y, McDowall R, Krishnamurthy A, Slavic D, Sekhon PK, Tyson GH, Ceric O, Stanhope MJ, Goodman LB. Evolutionary genomic analyses of canine E. coli infections identify a relic capsular locus associated with resistance to multiple classes of antimicrobials. Appl Environ Microbiol 2024:e0035424. [PMID: 39012166 DOI: 10.1128/aem.00354-24] [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: 02/28/2024] [Accepted: 06/08/2024] [Indexed: 07/17/2024] Open
Abstract
Infections caused by antimicrobial-resistant Escherichia coli are the leading cause of death attributed to antimicrobial resistance (AMR) worldwide, and the known AMR mechanisms involve a range of functional proteins. Here, we employed a pan-genome wide association study (GWAS) approach on over 1,000 E. coli isolates from sick dogs collected across the US and Canada and identified a strong statistical association (empirical P < 0.01) of AMR, involving a range of antibiotics to a group 1 capsular (CPS) gene cluster. This cluster included genes under relaxed selection pressure, had several loci missing, and had pseudogenes for other key loci. Furthermore, this cluster is widespread in E. coli and Klebsiella clinical isolates across multiple host species. Earlier studies demonstrated that the octameric CPS polysaccharide export protein Wza can transmit macrolide antibiotics into the E. coli periplasm. We suggest that the CPS in question, and its highly divergent Wza, functions as an antibiotic trap, preventing antimicrobial penetration. We also highlight the high diversity of lineages circulating in dogs across all regions studied, the overlap with human lineages, and regional prevalence of resistance to multiple antimicrobial classes. IMPORTANCE Much of the human genomic epidemiology data available for E. coli mechanism discovery studies has been heavily biased toward shiga-toxin producing strains from humans and livestock. E. coli occupies many niches and produces a wide variety of other significant pathotypes, including some implicated in chronic disease. We hypothesized that since dogs tend to share similar strains with their owners and are treated with similar antibiotics, their pathogenic isolates will harbor unexplored AMR mechanisms of importance to humans as well as animals. By comparing over 1,000 genomes with in vitro antimicrobial susceptibility data from sick dogs across the US and Canada, we identified a strong multidrug resistance association with an operon that appears to have once conferred a type 1 capsule production system.
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Affiliation(s)
| | | | | | - Jean K Millet
- Université Paris-Saclay, INRAE, UVSQ, Virologie et Immunologie Moléculaires, Jouy-en-Josas, Paris, France
| | - Qi Sun
- Cornell University, Ithaca, New York, USA
| | | | | | | | - Kelly Sams
- Cornell University, Ithaca, New York, USA
| | | | | | | | | | | | | | | | - Claire R Burbick
- Washington Animal Disease Diagnostic Laboratory, Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
| | - Rebecca Wolking
- Washington Animal Disease Diagnostic Laboratory, Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, USA
| | - Laura Peak
- Louisiana Animal Disease Diagnostic Laboratory, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, USA
| | - Yan Zhang
- Ohio Department of Agriculture Animal Disease Diagnostic Laboratory, Reynoldsburg, Ohio, USA
| | - Rebeccah McDowall
- University of Guelph, Animal Health Laboratory, Guelph, Ontario, Canada
| | | | - Durda Slavic
- University of Guelph, Animal Health Laboratory, Guelph, Ontario, Canada
| | | | - Gregory H Tyson
- US Food and Drug Administration, Veterinary Laboratory Investigation and Response Network, Laurel, Maryland, USA
| | - Olgica Ceric
- US Food and Drug Administration, Veterinary Laboratory Investigation and Response Network, Laurel, Maryland, USA
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Kang HM, Kim KR, Kim G, Lee DG, Kim YJ, Choi EH, Lee J, Yun KW. Antimicrobial resistance genes harbored in invasive Acinetobacter calcoaceticus-baumannii complex isolated from Korean children during the pre-COVID-19 pandemic periods, 2015-2020. Front Cell Infect Microbiol 2024; 14:1410997. [PMID: 39027135 PMCID: PMC11254764 DOI: 10.3389/fcimb.2024.1410997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Accepted: 05/15/2024] [Indexed: 07/20/2024] Open
Abstract
Background Acinetobacter baumannii (AB) has emerged as one of the most challenging pathogens worldwide, causing invasive infections in the critically ill patients due to their ability to rapidly acquire resistance to antibiotics. This study aimed to analyze antibiotic resistance genes harbored in AB and non-baumannii Acinetobacter calcoaceticus-baumannii (NB-ACB) complex causing invasive diseases in Korean children. Methods ACB complexes isolated from sterile body fluid of children in three referral hospitals were prospectively collected. Colistin susceptibility was additionally tested via broth microdilution. Whole genome sequencing was performed and antibiotic resistance genes were analyzed. Results During January 2015 to December 2020, a total of 67 ACB complexes were isolated from sterile body fluid of children in three referral hospitals. The median age of the patients was 0.6 (interquartile range, 0.1-7.2) years old. Among all the isolates, 73.1% (n=49) were confirmed as AB and others as NB-ACB complex by whole genome sequencing. Among the AB isolates, only 22.4% susceptible to carbapenem. In particular, all clonal complex (CC) 92 AB (n=33) showed multi-drug resistance, whereas 31.3% in non-CC92 AB (n=16) (P<0.001). NB-ACB showed 100% susceptibility to all classes of antibiotics except 3rd generation cephalosporin (72.2%). The main mechanism of carbapenem resistance in AB was the bla oxa23 gene with ISAba1 insertion sequence upstream. Presence of pmr gene and/or mutation of lpxA/C gene were not correlated with the phenotype of colistin resistance of ACB. All AB and NB-ACB isolates carried the abe and ade multidrug efflux pumps. Conclusions In conclusion, monitoring and research for resistome in ACB complex is needed to identify and manage drug-resistant AB, particularly CC92 AB carrying the bla oxa23 gene.
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Affiliation(s)
- Hyun Mi Kang
- Department of Pediatrics, College of Medicine, Seoul National University, Seoul, Republic of Korea
- Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
- Vaccine Bio Research Institute, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Kyung Ran Kim
- Department of Pediatrics, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Republic of Korea
| | - Gahee Kim
- Department of Pediatrics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Dong-gun Lee
- Vaccine Bio Research Institute, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
- Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Yae Jean Kim
- Department of Pediatrics, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Republic of Korea
| | - Eun Hwa Choi
- Department of Pediatrics, College of Medicine, Seoul National University, Seoul, Republic of Korea
- Department of Pediatrics, Seoul National University Children’s Hospital, Seoul, Republic of Korea
| | - Jina Lee
- Department of Pediatrics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Ki Wook Yun
- Department of Pediatrics, College of Medicine, Seoul National University, Seoul, Republic of Korea
- Department of Pediatrics, Seoul National University Children’s Hospital, Seoul, Republic of Korea
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Kim J, Lee Y, Kim I, Chang J, Hong S, Lee NK, Shum D, Baek S, Kim W, Jang S, Lee W. Reducing Peptidoglycan Crosslinking by Chemical Modulator Reverts β-lactam Resistance in Methicillin-Resistant Staphylococcus aureus. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2400858. [PMID: 38747156 PMCID: PMC11267302 DOI: 10.1002/advs.202400858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 04/11/2024] [Indexed: 07/25/2024]
Abstract
Small molecule can be utilized to restore the effectiveness of existing major classes of antibiotics against antibiotic-resistant bacteria. In this study, it is demonstrated that celastrol, a natural compound, can modify the bacterial cell wall and subsequently render bacteria more suceptible to β-lactam antibiotics. It is shown that celastrol leads to incomplete cell wall crosslinking by modulating levels of c-di-AMP, a secondary messenger, in methicillin-resistant Staphylococcus aureus (MRSA). This mechanism enables celastrol to act as a potentiator, effectively rendering MRSA susceptible to a range of penicillins and cephalosporins. Restoration of in vivo susceptibility of MRSA to methicillin is also demonstrated using a sepsis animal model by co-administering methicillin along with celastrol at a much lower amount than that of methicillin. The results suggest a novel approach for developing potentiators for major classes of antibiotics by exploring molecules that re-program metabolic pathways to reverse β-lactam-resistant strains to susceptible strains.
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Affiliation(s)
- Ji‐Hoon Kim
- School of PharmacySungkyunkwan UniversitySuwon16419Republic of Korea
| | - Yunmi Lee
- Antibacterial Resistance LaboratoryInstitut Pasteur KoreaSeongnam13488Republic of Korea
| | - Inseo Kim
- School of PharmacySungkyunkwan UniversitySuwon16419Republic of Korea
| | - JuOae Chang
- School of PharmacySungkyunkwan UniversitySuwon16419Republic of Korea
| | - Subin Hong
- School of PharmacySungkyunkwan UniversitySuwon16419Republic of Korea
| | - Na Kyung Lee
- Screening Discovery PlatformInstitut Pasteur KoreaSeongnam13488Republic of Korea
| | - David Shum
- Screening Discovery PlatformInstitut Pasteur KoreaSeongnam13488Republic of Korea
| | - Seongeun Baek
- College of PharmacyGraduate School of Pharmaceutical SciencesEwha Womans UniversitySeoul03760Republic of Korea
| | - Wooseong Kim
- College of PharmacyGraduate School of Pharmaceutical SciencesEwha Womans UniversitySeoul03760Republic of Korea
| | - Soojin Jang
- Antibacterial Resistance LaboratoryInstitut Pasteur KoreaSeongnam13488Republic of Korea
| | - Wonsik Lee
- School of PharmacySungkyunkwan UniversitySuwon16419Republic of Korea
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Diani E, Bianco G, Gatti M, Gibellini D, Gaibani P. Colistin: Lights and Shadows of an Older Antibiotic. Molecules 2024; 29:2969. [PMID: 38998921 PMCID: PMC11243602 DOI: 10.3390/molecules29132969] [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: 05/29/2024] [Revised: 06/17/2024] [Accepted: 06/20/2024] [Indexed: 07/14/2024] Open
Abstract
The emergence of antimicrobial resistance represents a serious threat to public health and for infections due to multidrug-resistant (MDR) microorganisms, representing one of the most important causes of death worldwide. The renewal of old antimicrobials, such as colistin, has been proposed as a valuable therapeutic alternative to the emergence of the MDR microorganisms. Although colistin is well known to present several adverse toxic effects, its usage in clinical practice has been reconsidered due to its broad spectrum of activity against Gram-negative (GN) bacteria and its important role of "last resort" agent against MDR-GN. Despite the revolutionary perspective of treatment with this old antimicrobial molecule, many questions remain open regarding the emergence of novel phenotypic traits of resistance and the optimal usage of the colistin in clinical practice. In last years, several forward steps have been made in the understanding of the resistance determinants, clinical usage, and pharmacological dosage of this molecule; however, different points regarding the role of colistin in clinical practice and the optimal pharmacokinetic/pharmacodynamic targets are not yet well defined. In this review, we summarize the mode of action, the emerging resistance determinants, and its optimal administration in the treatment of infections that are difficult to treat due to MDR Gram-negative bacteria.
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Affiliation(s)
- Erica Diani
- Department of Diagnostic and Public Health, Microbiology Section, University of Verona, Strada Le Grazie 8, 37134 Verona, Italy
| | - Gabriele Bianco
- Department of Experimental Medicine, University of Salento, 73100 Lecce, Italy
| | - Milo Gatti
- Department of Medical and Surgical Sciences, Alma Mater Studiorum, University of Bologna, 40126 Bologna, Italy
| | - Davide Gibellini
- Department of Diagnostic and Public Health, Microbiology Section, University of Verona, Strada Le Grazie 8, 37134 Verona, Italy
| | - Paolo Gaibani
- Department of Diagnostic and Public Health, Microbiology Section, University of Verona, Strada Le Grazie 8, 37134 Verona, Italy
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6
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Yang S, Wang H, Zhao D, Zhang S, Hu C. Polymyxins: recent advances and challenges. Front Pharmacol 2024; 15:1424765. [PMID: 38974043 PMCID: PMC11224486 DOI: 10.3389/fphar.2024.1424765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2024] [Accepted: 06/04/2024] [Indexed: 07/09/2024] Open
Abstract
Antibiotic resistance is a pressing global health challenge, and polymyxins have emerged as the last line of defense against multidrug-resistant Gram-negative (MDR-GRN) bacterial infections. Despite the longstanding utility of colistin, the complexities surrounding polymyxins in terms of resistance mechanisms and pharmacological properties warrant critical attention. This review consolidates current literature, focusing on polymyxins antibacterial mechanisms, resistance pathways, and innovative strategies to mitigate resistance. We are also investigating the pharmacokinetics of polymyxins to elucidate factors that influence their in vivo behavior. A comprehensive understanding of these aspects is pivotal for developing next-generation antimicrobials and optimizing therapeutic regimens. We underscore the urgent need for advancing research on polymyxins to ensure their continued efficacy against formidable bacterial challenges.
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Affiliation(s)
- Shan Yang
- Department of Critical Care Medicine, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Hairui Wang
- Institute of Respiratory Health, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Dan Zhao
- Department of Critical Care Medicine, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Shurong Zhang
- Department of Critical Care Medicine, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Chenggong Hu
- Department of Critical Care Medicine, West China Hospital of Sichuan University, Chengdu, Sichuan, China
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7
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Buchholz KR, Reichelt M, Johnson MC, Robinson SJ, Smith PA, Rutherford ST, Quinn JG. Potent activity of polymyxin B is associated with long-lived super-stoichiometric accumulation mediated by weak-affinity binding to lipid A. Nat Commun 2024; 15:4733. [PMID: 38830951 PMCID: PMC11148078 DOI: 10.1038/s41467-024-49200-5] [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: 11/15/2022] [Accepted: 05/23/2024] [Indexed: 06/05/2024] Open
Abstract
Polymyxins are gram-negative antibiotics that target lipid A, the conserved membrane anchor of lipopolysaccharide in the outer membrane. Despite their clinical importance, the molecular mechanisms underpinning polymyxin activity remain unresolved. Here, we use surface plasmon resonance to kinetically interrogate interactions between polymyxins and lipid A and derive a phenomenological model. Our analyses suggest a lipid A-catalyzed, three-state mechanism for polymyxins: transient binding, membrane insertion, and super-stoichiometric cluster accumulation with a long residence time. Accumulation also occurs for brevicidine, another lipid A-targeting antibacterial molecule. Lipid A modifications that impart polymyxin resistance and a non-bactericidal polymyxin derivative exhibit binding that does not evolve into long-lived species. We propose that transient binding to lipid A permeabilizes the outer membrane and cluster accumulation enables the bactericidal activity of polymyxins. These findings could establish a blueprint for discovery of lipid A-targeting antibiotics and provide a generalizable approach to study interactions with the gram-negative outer membrane.
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Affiliation(s)
- Kerry R Buchholz
- Department of Infectious Diseases, Genentech, Inc., South San Francisco, CA, USA.
| | - Mike Reichelt
- Department of Pathology, Genentech, Inc., South San Francisco, CA, USA
| | - Matthew C Johnson
- Department of Structural Biology, Genentech, Inc., South San Francisco, CA, USA
| | - Sarah J Robinson
- Department of Discovery Chemistry, Genentech, Inc., South San Francisco, CA, USA
| | - Peter A Smith
- Department of Infectious Diseases, Genentech, Inc., South San Francisco, CA, USA
- Revagenix, Inc., San Mateo, CA, USA
| | - Steven T Rutherford
- Department of Infectious Diseases, Genentech, Inc., South San Francisco, CA, USA.
| | - John G Quinn
- Department of Biochemical and Cellular Pharmacology, Genentech, Inc., South San Francisco, CA, USA.
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8
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Padhy I, Dwibedy SK, Mohapatra SS. A molecular overview of the polymyxin-LPS interaction in the context of its mode of action and resistance development. Microbiol Res 2024; 283:127679. [PMID: 38508087 DOI: 10.1016/j.micres.2024.127679] [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: 07/31/2023] [Revised: 03/03/2024] [Accepted: 03/06/2024] [Indexed: 03/22/2024]
Abstract
With the rising incidences of antimicrobial resistance (AMR) and the diminishing options of novel antimicrobial agents, it is paramount to decipher the molecular mechanisms of action and the emergence of resistance to the existing drugs. Polymyxin, a cationic antimicrobial lipopeptide, is used to treat infections by Gram-negative bacterial pathogens as a last option. Though polymyxins were identified almost seventy years back, their use has been restricted owing to toxicity issues in humans. However, their clinical use has been increasing in recent times resulting in the rise of polymyxin resistance. Moreover, the detection of "mobile colistin resistance (mcr)" genes in the environment and their spread across the globe have complicated the scenario. The mechanism of polymyxin action and the development of resistance is not thoroughly understood. Specifically, the polymyxin-bacterial lipopolysaccharide (LPS) interaction is a challenging area of investigation. The use of advanced biophysical techniques and improvement in molecular dynamics simulation approaches have furthered our understanding of this interaction, which will help develop polymyxin analogs with better bactericidal effects and lesser toxicity in the future. In this review, we have delved deeper into the mechanisms of polymyxin-LPS interactions, highlighting several models proposed, and the mechanisms of polymyxin resistance development in some of the most critical Gram-negative pathogens.
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Affiliation(s)
- Indira Padhy
- Molecular Microbiology Lab, Department of Biotechnology, Berhampur University, Bhanja Bihar, Berhampur 760007, Odisha, India
| | - Sambit K Dwibedy
- Molecular Microbiology Lab, Department of Biotechnology, Berhampur University, Bhanja Bihar, Berhampur 760007, Odisha, India
| | - Saswat S Mohapatra
- Molecular Microbiology Lab, Department of Biotechnology, Berhampur University, Bhanja Bihar, Berhampur 760007, Odisha, India.
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Bacon EE, Tran JS, Nadig N, Peters JM. Modular, inducible, and titratable expression systems for Escherichia coli and Acinetobacter baumannii. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.28.596346. [PMID: 38853957 PMCID: PMC11160707 DOI: 10.1101/2024.05.28.596346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Gene expression systems that transcend species barriers are needed for cross-species analysis of gene function. In particular, expression systems that can be utilized in both model and pathogenic bacteria underpin comparative functional approaches that inform conserved and variable features of bacterial physiology. Here, we develop replicative and integrative vectors alongside a novel, IPTG-inducible promoter that can be used in the model bacterium Escherichia coli K-12 as well as strains of the antibiotic-resistant pathogen, Acinetobacter baumannii. We generate modular vectors that transfer by conjugation at high efficiency and either replicate or integrate into the genome, depending on design. Embedded in these vectors, we also developed a synthetic, IPTG-inducible promoter, P abstBR , that induces to a high level, but is less leaky than the commonly used trc promoter. We show that P abstBR is titratable at both the population and single cell level, regardless of species, highlighting the utility of our expression systems for cross-species functional studies. Finally, as a proof of principle, we use our integrating vector to develop a reporter for the E. coli envelope stress σ factor, RpoE, and deploy the reporter in E. coli and A. baumannii, finding that A. baumannii does not recognize RpoE-dependent promoters unless RpoE is heterologously expressed. We envision that these vector and promoter tools will be valuable for the community of researchers that study fundamental biology of E. coli and A. baumannii.
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Affiliation(s)
- Emily E Bacon
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI 53706
| | - Jennifer S Tran
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI 53706
| | - Nischala Nadig
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI 53706
| | - Jason M Peters
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53726
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706
- Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI 53706
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10
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Zhuang J, Liu S, Du GF, Fang Z, Wu J, Li N, Zhong T, Xu J, He QY, Sun X. YjgM is a crotonyltransferase critical for polymyxin resistance of Escherichia coli. Cell Rep 2024; 43:114161. [PMID: 38678561 DOI: 10.1016/j.celrep.2024.114161] [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: 08/20/2023] [Revised: 02/02/2024] [Accepted: 04/11/2024] [Indexed: 05/01/2024] Open
Abstract
Lysine crotonylation has attracted widespread attention in recent years. However, little is known about bacterial crotonylation, particularly crotonyltransferase and decrotonylase, and its effects on antibiotic resistance. Our study demonstrates the ubiquitous presence of crotonylation in E. coli, which promotes bacterial resistance to polymyxin. We identify the crotonyltransferase YjgM and its regulatory pathways in E. coli with a focus on crotonylation. Further studies show that YjgM upregulates the crotonylation of the substrate protein PmrA, thereby boosting PmrA's affinity for binding to the promoter of eptA, which, in turn, promotes EptA expression and confers polymyxin resistance in E. coli. Additionally, we discover that PmrA's crucial crotonylation site and functional site is Lys 164. These significant discoveries highlight the role of crotonylation in bacterial drug resistance and offer a fresh perspective on creating antibacterial compounds.
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Affiliation(s)
- Jianpeng Zhuang
- MOE Key Laboratory of Tumor Molecular Biology and State Key Laboratory of Bioactive Molecules and Druggability Assessment, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou, China
| | - Shiqin Liu
- MOE Key Laboratory of Tumor Molecular Biology and State Key Laboratory of Bioactive Molecules and Druggability Assessment, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou, China
| | - Gao-Fei Du
- MOE Key Laboratory of Tumor Molecular Biology and State Key Laboratory of Bioactive Molecules and Druggability Assessment, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou, China; Key Laboratory of Laboratory Diagnostics, Medical Technology School, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Zuye Fang
- MOE Key Laboratory of Tumor Molecular Biology and State Key Laboratory of Bioactive Molecules and Druggability Assessment, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou, China
| | - Jiayi Wu
- MOE Key Laboratory of Tumor Molecular Biology and State Key Laboratory of Bioactive Molecules and Druggability Assessment, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou, China
| | - Nan Li
- MOE Key Laboratory of Tumor Molecular Biology and State Key Laboratory of Bioactive Molecules and Druggability Assessment, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou, China
| | - Tairan Zhong
- MOE Key Laboratory of Tumor Molecular Biology and State Key Laboratory of Bioactive Molecules and Druggability Assessment, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou, China
| | - Jiayi Xu
- MOE Key Laboratory of Tumor Molecular Biology and State Key Laboratory of Bioactive Molecules and Druggability Assessment, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou, China
| | - Qing-Yu He
- MOE Key Laboratory of Tumor Molecular Biology and State Key Laboratory of Bioactive Molecules and Druggability Assessment, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou, China.
| | - Xuesong Sun
- MOE Key Laboratory of Tumor Molecular Biology and State Key Laboratory of Bioactive Molecules and Druggability Assessment, Institute of Life and Health Engineering, College of Life Science and Technology, Jinan University, Guangzhou, China.
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11
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Singh G, Rana A, Smriti. Decoding antimicrobial resistance: unraveling molecular mechanisms and targeted strategies. Arch Microbiol 2024; 206:280. [PMID: 38805035 DOI: 10.1007/s00203-024-03998-2] [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: 03/31/2024] [Revised: 05/07/2024] [Accepted: 05/08/2024] [Indexed: 05/29/2024]
Abstract
Antimicrobial resistance poses a significant global health threat, necessitating innovative approaches for combatting it. This review explores various mechanisms of antimicrobial resistance observed in various strains of bacteria. We examine various strategies, including antimicrobial peptides (AMPs), novel antimicrobial materials, drug delivery systems, vaccines, antibody therapies, and non-traditional antibiotic treatments. Through a comprehensive literature review, the efficacy and challenges of these strategies are evaluated. Findings reveal the potential of AMPs in combating resistance due to their unique mechanisms and lower propensity for resistance development. Additionally, novel drug delivery systems, such as nanoparticles, show promise in enhancing antibiotic efficacy and overcoming resistance mechanisms. Vaccines and antibody therapies offer preventive measures, although challenges exist in their development. Non-traditional antibiotic treatments, including CRISPR-Cas systems, present alternative approaches to combat resistance. Overall, this review underscores the importance of multifaceted strategies and coordinated global efforts to address antimicrobial resistance effectively.
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Affiliation(s)
- Gagandeep Singh
- Department of Biosciences (UIBT), Chandigarh University, Punjab, 140413, India
| | - Anita Rana
- Department of Biosciences (UIBT), Chandigarh University, Punjab, 140413, India.
| | - Smriti
- Department of Biosciences (UIBT), Chandigarh University, Punjab, 140413, India
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12
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Bisaro F, Jackson-Litteken CD, McGuffey JC, Hooppaw AJ, Bodrog S, Jebeli L, Ortiz-Marquez JC, van Opijnen T, Scott NE, Di Venanzio G, Feldman MF. Diclofenac sensitizes multi-drug resistant Acinetobacter baumannii to colistin. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.17.594771. [PMID: 38798593 PMCID: PMC11118529 DOI: 10.1101/2024.05.17.594771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Acinetobacter baumannii causes life-threatening infections that are becoming difficult to treat due to increasing rates of multi-drug resistance (MDR) among clinical isolates. This has led the World Health Organization and the CDC to categorize MDR A. baumannii as a top priority for the research and development of new antibiotics. Colistin is the last-resort antibiotic to treat carbapenem-resistant A. baumannii . Not surprisingly, reintroduction of colistin has resulted in the emergence of colistin-resistant strains. Diclofenac is a nonsteroidal anti-inflammatory drug used to treat pain and inflammation associated with arthritis. In this work, we show that diclofenac sensitizes colistin-resistant A. baumannii clinical strains to colistin, in vitro and in a murine model of pneumonia. Diclofenac also reduced the colistin MIC of Klebsiella pneumoniae and Pseudomonas aeruginosa isolates. Transcriptomic and proteomic analyses revealed an upregulation of oxidative stress-related genes and downregulation of type IV pili induced by the combination treatment. Notably, the concentrations of colistin and diclofenac effective in the murine model were substantially lower than those determined in vitro , implying a stronger synergistic effect in vivo compared to in vitro . A pilA mutant strain, lacking the primary component of the type IV pili, became sensitive to colistin in the absence of diclofenac. This suggest that the downregulation of type IV pili is key for the synergistic activity of these drugs in vivo and indicates that colistin and diclofenac exert an anti-virulence effect. Together, these results suggest that the diclofenac can be repurposed with colistin to treat MDR A. baumannii .
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Papazachariou A, Tziolos RN, Karakonstantis S, Ioannou P, Samonis G, Kofteridis DP. Treatment Strategies of Colistin Resistance Acinetobacter baumannii Infections. Antibiotics (Basel) 2024; 13:423. [PMID: 38786151 PMCID: PMC11117269 DOI: 10.3390/antibiotics13050423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2024] [Revised: 05/01/2024] [Accepted: 05/02/2024] [Indexed: 05/25/2024] Open
Abstract
Acinetobacter baumannii has emerged as a pressing challenge in clinical practice, mainly due to the development of resistance to multiple antibiotics, including colistin, one of the last-resort treatments. This review highlights all the possible mechanisms of colistin resistance and the genetic basis contributing to this resistance, such as modifications to lipopolysaccharide or lipid A structures, alterations in outer membrane permeability via porins and heteroresistance. In light of this escalating threat, the review also evaluates available treatment options. The development of new antibiotics (cefiderocol, sulbactam/durlobactam) although not available everywhere, and the use of various combinations and synergistic drug combinations (including two or more of the following: a polymyxin, ampicillin/sulbactam, carbapenems, fosfomycin, tigecycline/minocycline, a rifamycin, and aminoglycosides) are discussed in the context of overcoming colistin resistance of A. baumannii infections. Although most studied combinations are polymyxin-based combinations, non-polymyxin-based combinations have been emerging as promising options. However, clinical data remain limited and continued investigation is essential to determine optimal therapeutic strategies against colistin-resistant A. baumannii.
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Affiliation(s)
- Andria Papazachariou
- Department of Internal Medicine & Infectious Diseases, University General Hospital of Heraklion, 71500 Heraklion, Greece; (A.P.); (R.-N.T.); (S.K.)
| | - Renatos-Nikolaos Tziolos
- Department of Internal Medicine & Infectious Diseases, University General Hospital of Heraklion, 71500 Heraklion, Greece; (A.P.); (R.-N.T.); (S.K.)
| | - Stamatis Karakonstantis
- Department of Internal Medicine & Infectious Diseases, University General Hospital of Heraklion, 71500 Heraklion, Greece; (A.P.); (R.-N.T.); (S.K.)
| | - Petros Ioannou
- Department of Internal Medicine & Infectious Diseases, University General Hospital of Heraklion, 71500 Heraklion, Greece; (A.P.); (R.-N.T.); (S.K.)
| | - George Samonis
- Department of Internal Medicine & Infectious Diseases, University General Hospital of Heraklion, 71500 Heraklion, Greece; (A.P.); (R.-N.T.); (S.K.)
- Metropolitan Hospital, Neon Faliron, 18547 Athens, Greece
| | - Diamantis P. Kofteridis
- Department of Internal Medicine & Infectious Diseases, University General Hospital of Heraklion, 71500 Heraklion, Greece; (A.P.); (R.-N.T.); (S.K.)
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14
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Karthikeyan D, Kumar S, Jayaprakash NS. A comprehensive review of recent developments in the gram-negative bacterial UDP-2,3-diacylglucosamine hydrolase (LpxH) enzyme. Int J Biol Macromol 2024; 267:131327. [PMID: 38574903 DOI: 10.1016/j.ijbiomac.2024.131327] [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: 11/20/2023] [Revised: 03/09/2024] [Accepted: 03/31/2024] [Indexed: 04/06/2024]
Abstract
The emergence of multidrug resistance has provided a great challenge to treat nosocomial infections, which have become a major health threat around the globe. Lipid A (an active endotoxin component), the final product of the Raetz lipid A metabolism pathway, is a membrane anchor of lipopolysaccharide (LPS) of the gram-negative bacterial outer membrane. It shields bacterial cells and serves as a protective barrier from antibiotics, thereby eliciting host response and making it difficult to destroy. UDP-2,3-diacylglucosamine pyrophosphate hydrolase (LpxH), a crucial peripheral membrane enzyme of the Raetz pathway, turned out to be the potential target to inhibit the production of Lipid A. This review provides a comprehensive compilation of information regarding the structural and functional aspects of LpxH, as well as its analogous LpxI and LpxG. In addition, apart from by providing a broader understanding of the enzyme-inhibitor mechanism, this review facilitates the development of novel drug candidates that can inhibit the pathogenicity of the lethal bacterium.
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Affiliation(s)
- Divyapriya Karthikeyan
- Centre for Bioseparation Technology, Vellore Institute of Technology, Vellore 632014, India
| | - Sanjit Kumar
- Department of Biotechnology, School of Interdisciplinary Education and Research, Guru Ghasidas Vishwavidyalaya, Bilaspur (A Central University), Chhattisgarh 495009, India
| | - N S Jayaprakash
- Centre for Bioseparation Technology, Vellore Institute of Technology, Vellore 632014, India.
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15
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Wang H, Ishchenko A, Skudlarek J, Shen P, Dzhekieva L, Painter RE, Chen YT, Bukhtiyarova M, Leithead A, Tracy R, Babaoglu K, Bahnck-Teets C, Buevich A, Cabalu TD, Labroli M, Lange H, Lei Y, Li W, Liu J, Mann PA, Meng T, Mitchell HJ, Mulhearn J, Scapin G, Sha D, Shaw AW, Si Q, Tong L, Wu C, Wu Z, Xiao JC, Xu M, Zhang LK, McKenney D, Miller RR, Black TA, Cooke A, Balibar CJ, Klein DJ, Raheem I, Walker SS. Cerastecins inhibit membrane lipooligosaccharide transport in drug-resistant Acinetobacter baumannii. Nat Microbiol 2024; 9:1244-1255. [PMID: 38649414 DOI: 10.1038/s41564-024-01667-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 03/06/2024] [Indexed: 04/25/2024]
Abstract
Carbapenem-resistant Acinetobacter baumannii infections have limited treatment options. Synthesis, transport and placement of lipopolysaccharide or lipooligosaccharide (LOS) in the outer membrane of Gram-negative bacteria are important for bacterial virulence and survival. Here we describe the cerastecins, inhibitors of the A. baumannii transporter MsbA, an LOS flippase. These molecules are potent and bactericidal against A. baumannii, including clinical carbapenem-resistant Acinetobacter baumannii isolates. Using cryo-electron microscopy and biochemical analysis, we show that the cerastecins adopt a serpentine configuration in the central vault of the MsbA dimer, stalling the enzyme and uncoupling ATP hydrolysis from substrate flipping. A derivative with optimized potency and pharmacokinetic properties showed efficacy in murine models of bloodstream or pulmonary A. baumannii infection. While resistance development is inevitable, targeting a clinically unexploited mechanism avoids existing antibiotic resistance mechanisms. Although clinical validation of LOS transport remains undetermined, the cerastecins may open a path to narrow-spectrum treatment modalities for important nosocomial infections.
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Affiliation(s)
- Hao Wang
- Merck & Co., Inc., West Point, PA, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Ying Lei
- Merck & Co., Inc., West Point, PA, USA
| | - Wei Li
- Merck & Co., Inc., West Point, PA, USA
| | - Jian Liu
- Merck & Co., Inc., West Point, PA, USA
| | | | - Tao Meng
- Merck & Co., Inc., Rahway, NJ, USA
| | | | | | | | - Deyou Sha
- Merck & Co., Inc., West Point, PA, USA
| | | | - Qian Si
- Merck & Co., Inc., West Point, PA, USA
| | - Ling Tong
- Merck & Co., Inc., West Point, PA, USA
| | | | - Zhe Wu
- Merck & Co., Inc., West Point, PA, USA
| | | | - Min Xu
- Merck & Co., Inc., West Point, PA, USA
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16
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Seo J, Kim JH, Ko N, Kim J, Moon K, Kim IS, Lee W. Development of novel indole-quinoline hybrid molecules targeting bacterial proton motive force. J Appl Microbiol 2024; 135:lxae104. [PMID: 38678002 DOI: 10.1093/jambio/lxae104] [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: 03/04/2024] [Revised: 04/01/2024] [Accepted: 04/18/2024] [Indexed: 04/29/2024]
Abstract
AIMS This study aimed to develop an editable structural scaffold for improving drug development, including pharmacokinetics and pharmacodynamics of antibiotics by using synthetic compounds derived from a (hetero)aryl-quinoline hybrid scaffold. METHODS AND RESULTS In this study, 18 CF3-substituted (hetero)aryl-quinoline hybrid molecules were examined for their potential antibacterial activity against Staphylococcus aureus by determining minimal inhibitory concentrations. These 18 synthetic compounds represent modifications to key regions of the quinoline N-oxide scaffold, enabling us to conduct a structure-activity relationship analysis for antibacterial potency. Among the compounds, 3 m exhibited potency against with both methicillin resistant S. aureus strains, as well as other Gram-positive bacteria, including Enterococcus faecalis and Bacillus subtilis. We demonstrated that 3 m disrupted the bacterial proton motive force (PMF) through monitoring the PMF and conducting the molecular dynamics simulations. Furthermore, we show that this mechanism of action, disrupting PMF, is challenging for S. aureus to overcome. We also validated this PMF inhibition mechanism of 3 m in an Acinetobacter baumannii strain with weaken lipopolysaccharides. Additionally, in Gram-negative bacteria, we demonstrated that 3 m exhibited a synergistic effect with colistin that disrupts the outer membrane of Gram-negative bacteria. CONCLUSIONS Our approach to developing editable synthetic novel antibacterials underscores the utility of CF3-substituted (hetero)aryl-quinoline scaffold for designing compounds targeting the bacterial proton motive force, and for further drug development, including pharmacokinetics and pharmacodynamics.
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Affiliation(s)
- Jinbeom Seo
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Ji-Hoon Kim
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Nayoung Ko
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jihyeon Kim
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Kyeongwon Moon
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - In Su Kim
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Wonsik Lee
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea
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17
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Nemeth AM, Young MM, Melander RJ, Smith RD, Ernst RK, Melander C. Identification of a 2-Aminobenzimidazole Scaffold that Potentiates Gram-Positive Selective Antibiotics Against Gram-Negative Bacteria. Chembiochem 2024; 25:e202400127. [PMID: 38451872 PMCID: PMC11021177 DOI: 10.1002/cbic.202400127] [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: 02/09/2024] [Revised: 03/07/2024] [Accepted: 03/07/2024] [Indexed: 03/09/2024]
Abstract
The development of novel therapeutic approaches is crucial in the fight against multi-drug resistant (MDR) bacteria, particularly gram-negative species. Small molecule adjuvants that enhance the activity of otherwise gram-positive selective antibiotics against gram-negative bacteria have the potential to expand current treatment options. We have previously reported adjuvants based upon a 2-aminoimidazole (2-AI) scaffold that potentiate macrolide antibiotics against several gram-negative pathogens. Herein, we report the discovery and structure-activity relationship (SAR) investigation of an additional class of macrolide adjuvants based upon a 2-aminobenzimidazole (2-ABI) scaffold. The lead compound lowers the minimum inhibitory concentration (MIC) of clarithromycin (CLR) from 512 to 2 μg/mL at 30 μM against Klebsiella pneumoniae 2146, and from 32 to 2 μg/mL at 5 μM, against Acinetobacter baumannii 5075. Preliminary investigation into the mechanism of action suggests that the compounds are binding to lipopolysaccharide (LPS) in K. pneumoniae, and modulating lipooligosaccharide (LOS) biosynthesis, assembly, or transport in A. baumannii.
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Affiliation(s)
- Ansley M Nemeth
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN-46556, USA
| | - Milah M Young
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN-46556, USA
| | - Roberta J Melander
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN-46556, USA
| | - Richard D Smith
- Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, MD-21201, USA
| | - Robert K Ernst
- Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, MD-21201, USA
| | - Christian Melander
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN-46556, USA
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18
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Mondal AH, Khare K, Saxena P, Debnath P, Mukhopadhyay K, Yadav D. A Review on Colistin Resistance: An Antibiotic of Last Resort. Microorganisms 2024; 12:772. [PMID: 38674716 PMCID: PMC11051878 DOI: 10.3390/microorganisms12040772] [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: 03/17/2024] [Revised: 04/04/2024] [Accepted: 04/08/2024] [Indexed: 04/28/2024] Open
Abstract
Antibiotic resistance has emerged as a significant global public health issue, driven by the rapid adaptation of microorganisms to commonly prescribed antibiotics. Colistin, previously regarded as a last-resort antibiotic for treating infections caused by Gram-negative bacteria, is increasingly becoming resistant due to chromosomal mutations and the acquisition of resistance genes carried by plasmids, particularly the mcr genes. The mobile colistin resistance gene (mcr-1) was first discovered in E. coli from China in 2016. Since that time, studies have reported different variants of mcr genes ranging from mcr-1 to mcr-10, mainly in Enterobacteriaceae from various parts of the world, which is a major concern for public health. The co-presence of colistin-resistant genes with other antibiotic resistance determinants further complicates treatment strategies and underscores the urgent need for enhanced surveillance and antimicrobial stewardship efforts. Therefore, understanding the mechanisms driving colistin resistance and monitoring its global prevalence are essential steps in addressing the growing threat of antimicrobial resistance and preserving the efficacy of existing antibiotics. This review underscores the critical role of colistin as a last-choice antibiotic, elucidates the mechanisms of colistin resistance and the dissemination of resistant genes, explores the global prevalence of mcr genes, and evaluates the current detection methods for colistin-resistant bacteria. The objective is to shed light on these key aspects with strategies for combating the growing threat of resistance to antibiotics.
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Affiliation(s)
- Aftab Hossain Mondal
- Department of Microbiology, Faculty of Allied Health Sciences, Shree Guru Gobind Singh Tricentenary University, Gurugram 122505, Haryana, India; (A.H.M.); (P.D.)
| | - Kriti Khare
- Antimicrobial Research Laboratory, School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India; (K.K.); (P.S.); (K.M.)
| | - Prachika Saxena
- Antimicrobial Research Laboratory, School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India; (K.K.); (P.S.); (K.M.)
| | - Parbati Debnath
- Department of Microbiology, Faculty of Allied Health Sciences, Shree Guru Gobind Singh Tricentenary University, Gurugram 122505, Haryana, India; (A.H.M.); (P.D.)
| | - Kasturi Mukhopadhyay
- Antimicrobial Research Laboratory, School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India; (K.K.); (P.S.); (K.M.)
| | - Dhananjay Yadav
- Department of Life Science, Yeungnam University, Gyeongsan 712-749, Republic of Korea
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19
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Boyd BM, House N, Carduck CW, Reed DL. Genomic Diversity in the Endosymbiotic Bacteria of Human Head Lice. Mol Biol Evol 2024; 41:msae064. [PMID: 38513084 PMCID: PMC10986857 DOI: 10.1093/molbev/msae064] [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: 10/25/2023] [Revised: 02/21/2024] [Accepted: 03/15/2024] [Indexed: 03/23/2024] Open
Abstract
Insects have repeatedly forged symbioses with heritable microbes, gaining novel traits. For the microbe, the transition to symbioses can lead to the degeneration of the symbiont's genome through transmission bottlenecks, isolation, and the loss of DNA repair enzymes. However, some insect-microbial symbioses have persisted for millions of years, suggesting that natural selection slows genetic drift and maintains functional consistency between symbiont populations. By sampling in multiple countries, we examine genomic diversity within a symbiont species, a heritable symbiotic bacterium found only in human head lice. We find that human head louse symbionts contain genetic diversity that appears to have arisen contemporaneously with the appearance of anatomically modern humans within Africa and/or during the colonization of Eurasia by humans. We predict that the observed genetic diversity underlies functional differences in extant symbiont lineages, through the inactivation of genes involved in symbiont membrane construction. Furthermore, we find evidence of additional gene losses prior to the appearance of modern humans, also impacting the symbiont membrane. From this, we conclude that symbiont genome degeneration is proceeding, via gene inactivation and subsequent loss, in human head louse symbionts, while genomic diversity is maintained. Collectively, our results provide a look into the genomic diversity within a single symbiont species and highlight the shared evolutionary history of humans, lice, and bacteria.
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Affiliation(s)
- Bret M Boyd
- Center for Biological Data Science, Life Sciences, Virginia Commonwealth University, Richmond, VA, USA
| | - Niyomi House
- Department of Biology, University of Nevada Reno, Reno, NV, USA
- Florida Museum of Natural History, University of Florida, Gainesville, FL, USA
| | - Christopher W Carduck
- Center for Biological Data Science, Life Sciences, Virginia Commonwealth University, Richmond, VA, USA
| | - David L Reed
- Florida Museum of Natural History, University of Florida, Gainesville, FL, USA
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20
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Gharaibeh MH, Abandeh YM, Elnasser ZA, Lafi SQ, Obeidat HM, Khanfar MA. Multi-drug Resistant Acinetobacter baumannii: Phenotypic and Genotypic Resistance Profiles and the Associated Risk Factors in Teaching Hospital in Jordan. J Infect Public Health 2024; 17:543-550. [PMID: 38367568 DOI: 10.1016/j.jiph.2024.01.018] [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: 06/08/2023] [Revised: 01/02/2024] [Accepted: 01/30/2024] [Indexed: 02/19/2024] Open
Abstract
BACKGROUND This study aimed to determine the prevalence of Antimicrobial Resistance Genes (ARGs), with a focus on colistin resistance in clinical A. baumannii, as well as the risk factors associated with A. baumannii infection in Jordanian patients. METHODS In total, 150 A. baumannii isolates were obtained from patients at a teaching hospital. The isolates were tested for antimicrobial susceptibility using disc diffusion and microdilution methods. PCR amplification was used to detect ARGs, and statistical analysis was conducted to evaluate the influence of identified risk factors on the ARGs acquisition. RESULTS More than 90% of A. baumannii isolates were resistant to monobactam, carbapenem, cephalosporins, Fluoroquinolones, penicillin, and β-lactam agents. Moreover, 20.6% of the isolates (n = 31) were colistin-resistant. Several ARGs were also detected in A. baumannii isolates. Univariate analysis indicated that risk factors and the carriage of ARGs were significantly associated P ≤ (0.05) with gender, invasive devices, immunodeficiency, systemic diseases, tumors, and covid-19. Logistic regression analysis indicated seven risk factors, and three protective factors were associated with the ARGs (armA, strA, and strB) P ≤ (0.05). In contrast, tetB and TEM were associated with 2 risk factors each P ≤ (0.05). CONCLUSION Our study indicates a high prevalence of MDR A. baumannii infections in ICU patients, as well as describing the case of colistin-resistant A. baumannii for the first time in Jordan. Additionally, the risk factors associated with ARGs-producing A. baumannii infections among ICU patients suggest a rapid emergence and spread of MDR A. baumannii without adequate surveillance and control measures.
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Affiliation(s)
- Mohammad H Gharaibeh
- Department of Basic Veterinary Medical Science, Faculty of Veterinary Medicine, Jordan University of Science and Technology, P. O. Box 3030, Irbid 22110, Jordan.
| | - Yaman M Abandeh
- Department of Basic Veterinary Medical Science, Faculty of Veterinary Medicine, Jordan University of Science and Technology, P. O. Box 3030, Irbid 22110, Jordan
| | - Ziad A Elnasser
- Department of Pathology and Microbiology, Faculty of Medicine, Jordan University of Science and Technology, P.O. Box 3030, Irbid 22110, Jordan
| | - Shawkat Q Lafi
- Department of Pathology and Public Health, Faculty of Veterinary Medicine, Jordan University of Science and Technology, P. O. Box 3030, Irbid 22110, Jordan
| | - Haneen M Obeidat
- Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, P.O. Box 3030, Irbid 22110, Jordan
| | - Malak A Khanfar
- Department of Biotechnology and Genetic Engineering, Faculty of Science and Arts, Jordan University of Science and Technology, P. O. Box 3030, Irbid 22110, Jordan
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21
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Yoon Y, Song S. Structural Insights into the Lipopolysaccharide Transport (Lpt) System as a Novel Antibiotic Target. J Microbiol 2024; 62:261-275. [PMID: 38816673 DOI: 10.1007/s12275-024-00137-w] [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: 03/19/2024] [Revised: 04/15/2024] [Accepted: 04/15/2024] [Indexed: 06/01/2024]
Abstract
Lipopolysaccharide (LPS) is a critical component of the extracellular leaflet within the bacterial outer membrane, forming an effective physical barrier against environmental threats in Gram-negative bacteria. After LPS is synthesized and matured in the bacterial cytoplasm and the inner membrane (IM), LPS is inserted into the outer membrane (OM) through the ATP-driven LPS transport (Lpt) pathway, which is an energy-intensive process. A trans-envelope complex that contains seven Lpt proteins (LptA-LptG) is crucial for extracting LPS from the IM and transporting it across the periplasm to the OM. The last step in LPS transport involves the mediation of the LptDE complex, facilitating the insertion of LPS into the outer leaflet of the OM. As the Lpt system plays an essential role in maintaining the impermeability of the OM via LPS decoration, the interactions between these interconnected subunits, which are meticulously regulated, may be potential targets for the development of new antibiotics to combat multidrug-resistant Gram-negative bacteria. In this review, we aimed to provide an overview of current research concerning the structural interactions within the Lpt system and their implications to clarify the function and regulation of LPS transport in the overall process of OM biogenesis. Additionally, we explored studies on the development of therapeutic inhibitors of LPS transport, the factors that limit success, and future prospects.
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Affiliation(s)
- Yurim Yoon
- Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology, Daejeon, 34114, Republic of Korea
| | - Saemee Song
- Infectious Diseases Therapeutic Research Center, Korea Research Institute of Chemical Technology, Daejeon, 34114, Republic of Korea.
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22
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Hummels KR. mSphere of Influence: Celebrating exceptions to the rule of lipid A essentiality. mSphere 2024; 9:e0063323. [PMID: 38421175 PMCID: PMC10964400 DOI: 10.1128/msphere.00633-23] [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: 03/02/2024] Open
Abstract
Kate Hummels works in the field of bacterial cell envelope biosynthesis and studies the regulation of the metabolic pathways needed to build the Gram-negative cell envelope. In this mSphere of Influence article, she reflects on how the papers "A penicillin-binding protein inhibits selection of colistin-resistant, lipopoligosaccharide-deficient Acinetobacter baumannii" by Boll et al. and "Caulobacter lipid A is conditionally dispensable in the absence of fur and in the presence of anionic sphingolipids" by Zik et al. made an impact on her by studying organisms that deviate from accepted norms to highlight the plethora of unanswered questions in cell envelope biology.
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Bhavya JN, Anugna SS, Premanath R. Sub-inhibitory concentrations of colistin and imipenem impact the expression of biofilm-associated genes in Acinetobacter baumannii. Arch Microbiol 2024; 206:169. [PMID: 38489041 DOI: 10.1007/s00203-024-03869-w] [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: 11/28/2023] [Revised: 01/23/2024] [Accepted: 01/24/2024] [Indexed: 03/17/2024]
Abstract
Acinetobacter baumannii is an opportunistic pathogen that is responsible for nosocomial infections. Imipenem and colistin are drugs that are commonly used to treat severe infections caused by A. baumannii, such as sepsis, ventilator-associated pneumonia, and bacteremia. However, some strains of A. baumannii have become resistant to these drugs, which is a concern for public health. Biofilms produced by A. baumannii increase their resistance to antibiotics and the cells within the inner layers of biofilm are exposed to sub-inhibitory concentrations (sub-MICs) of antibiotics. There is limited information available regarding how the genes of A. baumannii are linked to biofilm formation when the bacteria are exposed to sub-MICs of imipenem and colistin. Thus, this study's objective was to explore this relationship by examining the genes involved in biofilm formation in A. baumannii when exposed to low levels of imipenem and colistin. The study found that exposing an isolate of A. baumannii to low levels of these drugs caused changes in their drug susceptibility pattern. The relative gene expression profiles of the biofilm-associated genes exhibited a change in their expression profile during short-term and long-term exposure. This study highlights the potential consequences of overuse and misuse of antibiotics, which can help bacteria become resistant to these drugs.
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Affiliation(s)
- J N Bhavya
- Nitte (Deemed to be University), Nitte University Centre for Science Education and Research, Paneer Campus, Deralakatte, Mangaluru, Karnataka, 575018, India
| | - Sureddi Sai Anugna
- Nitte (Deemed to be University), Nitte University Centre for Science Education and Research, Paneer Campus, Deralakatte, Mangaluru, Karnataka, 575018, India
| | - Ramya Premanath
- Nitte (Deemed to be University), Nitte University Centre for Science Education and Research, Paneer Campus, Deralakatte, Mangaluru, Karnataka, 575018, India.
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24
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Karampatakis T, Tsergouli K, Behzadi P. Pan-Genome Plasticity and Virulence Factors: A Natural Treasure Trove for Acinetobacter baumannii. Antibiotics (Basel) 2024; 13:257. [PMID: 38534692 DOI: 10.3390/antibiotics13030257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 02/17/2024] [Accepted: 03/12/2024] [Indexed: 03/28/2024] Open
Abstract
Acinetobacter baumannii is a Gram-negative pathogen responsible for a variety of community- and hospital-acquired infections. It is recognized as a life-threatening pathogen among hospitalized individuals and, in particular, immunocompromised patients in many countries. A. baumannii, as a member of the ESKAPE group, encompasses high genomic plasticity and simultaneously is predisposed to receive and exchange the mobile genetic elements (MGEs) through horizontal genetic transfer (HGT). Indeed, A. baumannii is a treasure trove that contains a high number of virulence factors. In accordance with these unique pathogenic characteristics of A. baumannii, the authors aim to discuss the natural treasure trove of pan-genome and virulence factors pertaining to this bacterial monster and try to highlight the reasons why this bacterium is a great concern in the global public health system.
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Affiliation(s)
| | - Katerina Tsergouli
- Microbiology Department, Agios Pavlos General Hospital, 55134 Thessaloniki, Greece
| | - Payam Behzadi
- Department of Microbiology, Shahr-e-Qods Branch, Islamic Azad University, Tehran 37541-374, Iran
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25
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Noel HR, Keerthi S, Ren X, Winkelman JD, Troutman JM, Palmer LD. Genetic synergy between Acinetobacter baumannii undecaprenyl phosphate biosynthesis and the Mla system impacts cell envelope and antimicrobial resistance. mBio 2024; 15:e0280423. [PMID: 38364179 PMCID: PMC10936186 DOI: 10.1128/mbio.02804-23] [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: 10/16/2023] [Accepted: 01/17/2024] [Indexed: 02/18/2024] Open
Abstract
Acinetobacter baumannii is a Gram-negative bacterial pathogen that poses a major health concern due to increasing multidrug resistance. The Gram-negative cell envelope is a key barrier to antimicrobial entry and includes an inner and outer membrane. The maintenance of lipid asymmetry (Mla) system is the main homeostatic mechanism by which Gram-negative bacteria maintain outer membrane asymmetry. Loss of the Mla system in A. baumannii results in attenuated virulence and increased susceptibility to membrane stressors and some antibiotics. We recently reported two strain variants of the A. baumannii type strain ATCC 17978: 17978VU and 17978UN. Here, ∆mlaF mutants in the two ATCC 17978 strains display different phenotypes for membrane stress resistance, antibiotic resistance, and pathogenicity in a murine pneumonia model. Although allele differences in obgE were previously reported to synergize with ∆mlaF to affect growth and stringent response, obgE alleles do not affect membrane stress resistance. Instead, a single-nucleotide polymorphism (SNP) in the essential gene encoding undecaprenyl pyrophosphate (Und-PP) synthase, uppS, results in decreased enzymatic rate and decrease in total Und-P levels in 17978UN compared to 17978VU. The UppSUN variant synergizes with ∆mlaF to reduce capsule and lipooligosaccharide (LOS) levels, increase susceptibility to membrane stress and antibiotics, and reduce persistence in a mouse lung infection. Und-P is a lipid glycan carrier required for the biosynthesis of A. baumannii capsule, cell wall, and glycoproteins. These findings uncover synergy between Und-P and the Mla system in maintaining the A. baumannii cell envelope and antibiotic resistance.IMPORTANCEAcinetobacter baumannii is a critical threat to global public health due to its multidrug resistance and persistence in hospital settings. Therefore, novel therapeutic approaches are urgently needed. We report that a defective undecaprenyl pyrophosphate synthase (UppS) paired with a perturbed Mla system leads to synthetically sick cells that are more susceptible to clinically relevant antibiotics and show reduced virulence in a lung infection model. These results suggest that targeting UppS or undecaprenyl species and the Mla system may resensitize A. baumannii to antibiotics in combination therapies. This work uncovers a previously unknown synergistic relationship in cellular envelope homeostasis that could be leveraged for use in combination therapy against A. baumannii.
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Affiliation(s)
- Hannah R. Noel
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, Illinois, USA
| | - Sowmya Keerthi
- Department of Chemistry, University of North Carolina Charlotte, Charlotte, North Carolina, USA
| | - Xiaomei Ren
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, Illinois, USA
| | | | - Jerry M. Troutman
- Department of Chemistry, University of North Carolina Charlotte, Charlotte, North Carolina, USA
| | - Lauren D. Palmer
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, Illinois, USA
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VanOtterloo LM, Macias LA, Powers MJ, Brodbelt JS, Trent MS. Characterization of Acinetobacter baumannii core oligosaccharide synthesis reveals novel aspects of lipooligosaccharide assembly. mBio 2024; 15:e0301323. [PMID: 38349180 PMCID: PMC10936431 DOI: 10.1128/mbio.03013-23] [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: 11/06/2023] [Accepted: 01/12/2024] [Indexed: 03/14/2024] Open
Abstract
A fundamental feature of Gram-negative bacteria is their outer membrane that protects the cell against environmental stressors. This defense is predominantly due to its asymmetry, with glycerophospholipids located in the inner leaflet and lipopolysaccharide (LPS) or lipooligosaccharide (LOS) confined to the outer leaflet. LPS consists of a lipid A anchor, a core oligosaccharide, and a distal O-antigen while LOS lacks O-antigen. While LPS/LOS is typically essential for growth, this is not the case for Acinetobacter baumannii. Despite this unique property, the synthesis of the core oligosaccharide of A. baumannii LOS is not well-described. Here, we characterized the LOS chemotypes of A. baumannii strains with mutations in a predicted core oligosaccharide locus via tandem mass spectrometry. This allowed for an extensive identification of genes required for core assembly that can be exploited to generate precise structural LOS modifications in many A. baumannii strains. We further investigated two chemotypically identical yet phenotypically distinct mutants, ∆2903 and ∆lpsB, that exposed a possible link between LOS and the peptidoglycan cell wall-two cell envelope components whose coordination has not yet been described in A. baumannii. Selective reconstruction of the core oligosaccharide via expression of 2903 and LpsB revealed that these proteins rely on each other for the unusual tandem transfer of two residues, KdoIII and N-acetylglucosaminuronic acid. The data presented not only allow for better usage of A. baumannii as a tool to study outer membrane integrity but also provide further evidence for a novel mechanism of core oligosaccharide assembly. IMPORTANCE Acinetobacter baumannii is a multidrug-resistant pathogen that produces lipooligosaccharide (LOS), a glycolipid that confers protective asymmetry to the bacterial outer membrane. The core oligosaccharide is a ubiquitous component of LOS that typically follows a well-established model of synthesis. In addition to providing an extensive analysis of the genes involved in the synthesis of the core region, we demonstrate that this organism has evidently diverged from the long-held archetype of core synthesis. Moreover, our data suggest that A. baumannii LOS assembly is important for cell division and likely intersects with the synthesis of the peptidoglycan cell wall, another essential component of the Gram-negative cell envelope. This connection between LOS and cell wall synthesis provides an intriguing foundation for a unique method of outer membrane biogenesis and cell envelope coordination.
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Affiliation(s)
- Leah M. VanOtterloo
- Department of Microbiology, College of Art and Sciences, University of Georgia, Athens, Georgia, USA
| | - Luis A. Macias
- Department of Chemistry, University of Texas at Austin, Austin, Texas, USA
| | - Matthew J. Powers
- Department of Microbiology, College of Art and Sciences, University of Georgia, Athens, Georgia, USA
| | | | - M. Stephen Trent
- Department of Microbiology, College of Art and Sciences, University of Georgia, Athens, Georgia, USA
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
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Rout BP, Dash SK, Otta S, Behera B, Praharaj I, Sahu KK. Colistin resistance in carbapenem non-susceptible Acinetobacter baumanii in a tertiary care hospital in India: clinical characteristics, antibiotic susceptibility and molecular characterization. Mol Biol Rep 2024; 51:357. [PMID: 38400950 DOI: 10.1007/s11033-023-08982-5] [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: 09/09/2023] [Accepted: 10/24/2023] [Indexed: 02/26/2024]
Abstract
INTRODUCTION Acinetobacter baumanii (AB) is a bacterium of concern in the hospital setup due to its ability to thrive in unfavorable conditions and the rapid emergence of antibiotic resistance. Carbapenem resistance in this organism is disheartening, further clouded by the emergence of colistin resistance. AIM The present prospective study aims to note the epidemiology, molecular profile, and clinical outcome of patients with colistin resistance AB infections in a multispecialty tertiary care setup in Odisha, Eastern India. METHODS All AB strains received from March 2021 to February 2022, identified by Vitek2 (Biomerieux) and confirmed by oxa-51 genes, were included. Carbapenem and colistin resistance were identified as per CLSI guidelines. Known mutations for blaOXA-23-like, blaIMP, blaVIM, blaKP, lpxA, lpxC, pmrA, pmrB, and plasmid mediated mcr (mcr1-5) were screened by conventional PCR techniques. The clinical outcome was noted retrospectively from case sheets. Data was entered in MS Excel and tabulated using SPSS software. RESULTS In the study period, 350 AB were obtained, of which 317(90.5%) were carbapenem resistant (CRAB). Among the CRAB isolates, 19 (5.9%) were colistin resistant (ABCoR). The most valuable antibiotics in the study were tigecycline (65.4% in ABCoI; 31.6% in ABCoR) and minocycline (44.3% in CI; 36.8% in CR). There was a significant difference in mortality among ABCoI and ABCoR infections. bla OXA was the predominant carbapenem resistance genotype, while pmrA was the predominant colistin resistant genotype. There were no plasmid mediated mcr genes detected in the present study.
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Affiliation(s)
- Bidyut Prava Rout
- Department of Microbiology, IMS & SUM Hospital, Bhubaneswar, Odisha, India
| | - Sumesh Kumar Dash
- Department of Microbiology, IMS & SUM Hospital, Bhubaneswar, Odisha, India
| | - Sarita Otta
- Department of Microbiology, IMS & SUM Hospital, Bhubaneswar, Odisha, India.
| | - Birasen Behera
- Department of Microbiology, IMS & SUM Hospital, Bhubaneswar, Odisha, India
| | - Ira Praharaj
- Department of Virology, RMRC (ICMR), Bhubaneswar, Odisha, India
| | - Kundan Kumar Sahu
- Department of Microbiology, IMS & SUM Hospital, Bhubaneswar, Odisha, India.
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Ward RD, Tran JS, Banta AB, Bacon EE, Rose WE, Peters JM. Essential gene knockdowns reveal genetic vulnerabilities and antibiotic sensitivities in Acinetobacter baumannii. mBio 2024; 15:e0205123. [PMID: 38126769 PMCID: PMC10865783 DOI: 10.1128/mbio.02051-23] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 11/20/2023] [Indexed: 12/23/2023] Open
Abstract
The emergence of multidrug-resistant Gram-negative bacteria underscores the need to define genetic vulnerabilities that can be therapeutically exploited. The Gram-negative pathogen, Acinetobacter baumannii, is considered an urgent threat due to its propensity to evade antibiotic treatments. Essential cellular processes are the target of existing antibiotics and a likely source of new vulnerabilities. Although A. baumannii essential genes have been identified by transposon sequencing, they have not been prioritized by sensitivity to knockdown or antibiotics. Here, we take a systems biology approach to comprehensively characterize A. baumannii essential genes using CRISPR interference (CRISPRi). We show that certain essential genes and pathways are acutely sensitive to knockdown, providing a set of vulnerable targets for future therapeutic investigation. Screening our CRISPRi library against last-resort antibiotics uncovered genes and pathways that modulate beta-lactam sensitivity, an unexpected link between NADH dehydrogenase activity and growth inhibition by polymyxins, and anticorrelated phenotypes that may explain synergy between polymyxins and rifamycins. Our study demonstrates the power of systematic genetic approaches to identify vulnerabilities in Gram-negative pathogens and uncovers antibiotic-essential gene interactions that better inform combination therapies.IMPORTANCEAcinetobacter baumannii is a hospital-acquired pathogen that is resistant to many common antibiotic treatments. To combat resistant A. baumannii infections, we need to identify promising therapeutic targets and effective antibiotic combinations. In this study, we comprehensively characterize the genes and pathways that are critical for A. baumannii viability. We show that genes involved in aerobic metabolism are central to A. baumannii physiology and may represent appealing drug targets. We also find antibiotic-gene interactions that may impact the efficacy of carbapenems, rifamycins, and polymyxins, providing a new window into how these antibiotics function in mono- and combination therapies. Our studies offer a useful approach for characterizing interactions between drugs and essential genes in pathogens to inform future therapies.
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Affiliation(s)
- Ryan D. Ward
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jennifer S. Tran
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Amy B. Banta
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Emily E. Bacon
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Warren E. Rose
- Pharmacy Practice Division, School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jason M. Peters
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, Wisconsin, USA
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Abou Fayad A, Haraoui LP, Sleiman A, Hussein H, Grenier F, Derbaj G, Itani D, Iweir S, Sherri N, Bazzi W, Rasheed S, Tanelian A, Miari M, el Hafi B, Kanj SS, Kanafani ZA, Daoud Z, Araj GF, Matar GM. Molecular Characteristics of Colistin Resistance in Acinetobacter baumannii and the Activity of Antimicrobial Combination Therapy in a Tertiary Care Medical Center in Lebanon. Microorganisms 2024; 12:349. [PMID: 38399753 PMCID: PMC10892383 DOI: 10.3390/microorganisms12020349] [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: 12/22/2023] [Revised: 01/21/2024] [Accepted: 01/26/2024] [Indexed: 02/25/2024] Open
Abstract
(1) Background: Infections with pan-drug-resistant (PDR) bacteria, such as A. baumannii, are becoming increasingly common, especially in healthcare facilities. In this study, we selected 15 colistin-resistant clinical A. baumannii isolates from a hospital in Beirut, Lebanon, to test combination therapies and determine their sequence types (STs) and the mechanism of colistin resistance using whole-genome sequencing (WGS). (2) Methods: Antimicrobial susceptibility testing via broth microdilution against 12 antimicrobials from different classes and growth rate assays were performed. A checkerboard assay was conducted on PDR isolates using six different antimicrobials, each in combination with colistin. Genomic DNA was extracted from all isolates and subjected to WGS. (3) Results: All isolates were resistant to all tested antimicrobials with the one exception that was susceptible to gentamicin. Combining colistin with either meropenem, ceftolozane-tazobactam, or teicoplanin showed synergistic activity. Sequencing data revealed that 67% of the isolates belonged to Pasteur ST2 and 33% to ST187. Furthermore, these isolates harbored a number of resistance genes, including blaOXA-23. Mutations in the pmrC gene were behind colistin resistance. (4) Conclusions: With the rise in antimicrobial resistance and the absence of novel antimicrobial production, alternative treatments must be found. The combination therapy results from this study suggest treatment options for PDR ST2 A. baumannii-infected patients.
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Affiliation(s)
- Antoine Abou Fayad
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon; (A.A.F.); (A.S.); (G.D.); (D.I.); (S.I.); (N.S.); (W.B.); (S.R.); (A.T.); (M.M.)
- Center for Infectious Diseases Research, American University of Beirut, Beirut 1107 2020, Lebanon; (S.S.K.); (Z.A.K.); (G.F.A.)
- World Health Organization (WHO) Collaborating Center for Reference and Research on Bacterial Pathogens, Beirut 1107 2020, Lebanon
| | - Louis-Patrick Haraoui
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada;
- Centre de recherche Charles-Le Moyne, Hôpital Charles-Le Moyne, Greenfield Park, QC J4V 2G9, Canada
| | - Ahmad Sleiman
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon; (A.A.F.); (A.S.); (G.D.); (D.I.); (S.I.); (N.S.); (W.B.); (S.R.); (A.T.); (M.M.)
- Center for Infectious Diseases Research, American University of Beirut, Beirut 1107 2020, Lebanon; (S.S.K.); (Z.A.K.); (G.F.A.)
- World Health Organization (WHO) Collaborating Center for Reference and Research on Bacterial Pathogens, Beirut 1107 2020, Lebanon
| | - Hadi Hussein
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon; (A.A.F.); (A.S.); (G.D.); (D.I.); (S.I.); (N.S.); (W.B.); (S.R.); (A.T.); (M.M.)
- Center for Infectious Diseases Research, American University of Beirut, Beirut 1107 2020, Lebanon; (S.S.K.); (Z.A.K.); (G.F.A.)
- World Health Organization (WHO) Collaborating Center for Reference and Research on Bacterial Pathogens, Beirut 1107 2020, Lebanon
| | - Frédéric Grenier
- Department of Biology, Faculty of Science, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada;
| | - Ghada Derbaj
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon; (A.A.F.); (A.S.); (G.D.); (D.I.); (S.I.); (N.S.); (W.B.); (S.R.); (A.T.); (M.M.)
- Center for Infectious Diseases Research, American University of Beirut, Beirut 1107 2020, Lebanon; (S.S.K.); (Z.A.K.); (G.F.A.)
- World Health Organization (WHO) Collaborating Center for Reference and Research on Bacterial Pathogens, Beirut 1107 2020, Lebanon
| | - Dana Itani
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon; (A.A.F.); (A.S.); (G.D.); (D.I.); (S.I.); (N.S.); (W.B.); (S.R.); (A.T.); (M.M.)
- Center for Infectious Diseases Research, American University of Beirut, Beirut 1107 2020, Lebanon; (S.S.K.); (Z.A.K.); (G.F.A.)
- World Health Organization (WHO) Collaborating Center for Reference and Research on Bacterial Pathogens, Beirut 1107 2020, Lebanon
| | - Sereen Iweir
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon; (A.A.F.); (A.S.); (G.D.); (D.I.); (S.I.); (N.S.); (W.B.); (S.R.); (A.T.); (M.M.)
- Center for Infectious Diseases Research, American University of Beirut, Beirut 1107 2020, Lebanon; (S.S.K.); (Z.A.K.); (G.F.A.)
- World Health Organization (WHO) Collaborating Center for Reference and Research on Bacterial Pathogens, Beirut 1107 2020, Lebanon
| | - Nour Sherri
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon; (A.A.F.); (A.S.); (G.D.); (D.I.); (S.I.); (N.S.); (W.B.); (S.R.); (A.T.); (M.M.)
- Center for Infectious Diseases Research, American University of Beirut, Beirut 1107 2020, Lebanon; (S.S.K.); (Z.A.K.); (G.F.A.)
- World Health Organization (WHO) Collaborating Center for Reference and Research on Bacterial Pathogens, Beirut 1107 2020, Lebanon
| | - Wael Bazzi
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon; (A.A.F.); (A.S.); (G.D.); (D.I.); (S.I.); (N.S.); (W.B.); (S.R.); (A.T.); (M.M.)
- Center for Infectious Diseases Research, American University of Beirut, Beirut 1107 2020, Lebanon; (S.S.K.); (Z.A.K.); (G.F.A.)
- World Health Organization (WHO) Collaborating Center for Reference and Research on Bacterial Pathogens, Beirut 1107 2020, Lebanon
| | - Sari Rasheed
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon; (A.A.F.); (A.S.); (G.D.); (D.I.); (S.I.); (N.S.); (W.B.); (S.R.); (A.T.); (M.M.)
- Center for Infectious Diseases Research, American University of Beirut, Beirut 1107 2020, Lebanon; (S.S.K.); (Z.A.K.); (G.F.A.)
- World Health Organization (WHO) Collaborating Center for Reference and Research on Bacterial Pathogens, Beirut 1107 2020, Lebanon
| | - Arax Tanelian
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon; (A.A.F.); (A.S.); (G.D.); (D.I.); (S.I.); (N.S.); (W.B.); (S.R.); (A.T.); (M.M.)
- Center for Infectious Diseases Research, American University of Beirut, Beirut 1107 2020, Lebanon; (S.S.K.); (Z.A.K.); (G.F.A.)
- World Health Organization (WHO) Collaborating Center for Reference and Research on Bacterial Pathogens, Beirut 1107 2020, Lebanon
| | - Mariam Miari
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon; (A.A.F.); (A.S.); (G.D.); (D.I.); (S.I.); (N.S.); (W.B.); (S.R.); (A.T.); (M.M.)
- Center for Infectious Diseases Research, American University of Beirut, Beirut 1107 2020, Lebanon; (S.S.K.); (Z.A.K.); (G.F.A.)
- World Health Organization (WHO) Collaborating Center for Reference and Research on Bacterial Pathogens, Beirut 1107 2020, Lebanon
| | - Bassam el Hafi
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon; (A.A.F.); (A.S.); (G.D.); (D.I.); (S.I.); (N.S.); (W.B.); (S.R.); (A.T.); (M.M.)
- Center for Infectious Diseases Research, American University of Beirut, Beirut 1107 2020, Lebanon; (S.S.K.); (Z.A.K.); (G.F.A.)
- World Health Organization (WHO) Collaborating Center for Reference and Research on Bacterial Pathogens, Beirut 1107 2020, Lebanon
| | - Souha S. Kanj
- Center for Infectious Diseases Research, American University of Beirut, Beirut 1107 2020, Lebanon; (S.S.K.); (Z.A.K.); (G.F.A.)
- Division of Infectious Diseases, Department of Internal Medicine, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon
| | - Zeina A. Kanafani
- Center for Infectious Diseases Research, American University of Beirut, Beirut 1107 2020, Lebanon; (S.S.K.); (Z.A.K.); (G.F.A.)
- Division of Infectious Diseases, Department of Internal Medicine, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon
| | - Ziad Daoud
- Laboratory Department, My Michigan Health Midland Medical Center, College of Medicine, Central Michigan University, Saginaw, MI 48602, USA;
| | - George F. Araj
- Center for Infectious Diseases Research, American University of Beirut, Beirut 1107 2020, Lebanon; (S.S.K.); (Z.A.K.); (G.F.A.)
- Department of Pathology and Laboratory Medicine, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon
| | - Ghassan M. Matar
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut 1107 2020, Lebanon; (A.A.F.); (A.S.); (G.D.); (D.I.); (S.I.); (N.S.); (W.B.); (S.R.); (A.T.); (M.M.)
- Center for Infectious Diseases Research, American University of Beirut, Beirut 1107 2020, Lebanon; (S.S.K.); (Z.A.K.); (G.F.A.)
- World Health Organization (WHO) Collaborating Center for Reference and Research on Bacterial Pathogens, Beirut 1107 2020, Lebanon
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Vijayakumar S, Swetha RG, Bakthavatchalam YD, Vasudevan K, Abirami Shankar B, Kirubananthan A, Walia K, Ramaiah S, Biswas I, Veeraraghavan B, Anbarasu A. Genomic investigation unveils colistin resistance mechanism in carbapenem-resistant Acinetobacter baumannii clinical isolates. Microbiol Spectr 2024; 12:e0251123. [PMID: 38214512 PMCID: PMC10846133 DOI: 10.1128/spectrum.02511-23] [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: 06/15/2023] [Accepted: 11/29/2023] [Indexed: 01/13/2024] Open
Abstract
Colistin resistance in Acinetobacter baumannii is mediated by multiple mechanisms. Recently, mutations within pmrABC two-component system and overexpression of eptA gene due to upstream insertion of ISAba1 have been shown to play a major role. Thus, the aim of our study is to characterize colistin resistance mechanisms among the clinical isolates of A. baumannii in India. A total of 207 clinical isolates of A. baumannii collected from 2016 to 2019 were included in this study. Mutations within lipid A biosynthesis and pmrABC genes were characterized by whole-genome shotgun sequencing. Twenty-eight complete genomes were further characterized by hybrid assembly approach to study insertional inactivation of lpx genes and the association of ISAba1-eptA. Several single point mutations (SNPs), like M12I in pmrA, A138T and A444V in pmrB, and E117K in lpxD, were identified. We are the first to report two novel SNPs (T7I and V383I) in the pmrC gene. Among the five colistin-resistant A. baumannii isolates where complete genome was available, the analysis showed that three of the five isolates had ISAba1 insertion upstream of eptA. No mcr genes were identified among the isolates. We mapped the SNPs on the respective protein structures to understand the effect on the protein activity. We found that majority of the SNPs had little effect on the putative protein function; however, some SNPs might destabilize the local structure. Our study highlights the diversity of colistin resistance mechanisms occurring in A. baumannii, and ISAba1-driven eptA overexpression is responsible for colistin resistance among the Indian isolates.IMPORTANCEAcinetobacter baumannii is a Gram-negative, emerging and opportunistic bacterial pathogen that is often associated with a wide range of nosocomial infections. The treatment of these infections is hindered by increase in the occurrence of A. baumannii strains that are resistant to most of the existing antibiotics. The current drug of choice to treat the infection caused by A. baumannii is colistin, but unfortunately, the bacteria started to show resistance to the last-resort antibiotic. The loss of lipopolysaccharides and mutations in lipid A biosynthesis genes are the main reasons for the colistin resistance. The present study characterized 207 A. baumannii clinical isolates and constructed complete genomes of 28 isolates to recognize the mechanisms of colistin resistance. We showed the mutations in the colistin-resistant variants within genes essential for lipid A biosynthesis and that cause these isolates to lose the ability to produce lipopolysaccharides.
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Affiliation(s)
- Saranya Vijayakumar
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Rayapadi G. Swetha
- Medical and Biological Computing Laboratory, School of Biosciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| | | | - Karthick Vasudevan
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
- Department of Biotechnology, School of Applied Sciences, REVA University, Bangalore, India
| | - Baby Abirami Shankar
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | | | - Kamini Walia
- Division of Epidemiology and Communicable Diseases, Indian Council for Medical Research, New Delhi, India
| | - Sudha Ramaiah
- Medical and Biological Computing Laboratory, School of Biosciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| | - Indranil Biswas
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas, USA
| | - Balaji Veeraraghavan
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Anand Anbarasu
- Medical and Biological Computing Laboratory, School of Biosciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
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Yaikhan T, Chukamnerd A, Singkhamanan K, Nokchan N, Chintakovid N, Chusri S, Pomwised R, Wonglapsuwan M, Surachat K. Genomic Characterization of Mobile Genetic Elements Associated with Multidrug-Resistant Acinetobacter Non- baumannii Species from Southern Thailand. Antibiotics (Basel) 2024; 13:149. [PMID: 38391535 PMCID: PMC10886146 DOI: 10.3390/antibiotics13020149] [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: 12/22/2023] [Revised: 01/23/2024] [Accepted: 01/31/2024] [Indexed: 02/24/2024] Open
Abstract
This study investigated the genetic diversity, antimicrobial resistance profiles, and virulence characteristics of Acinetobacter non-baumannii isolates obtained from four hospitals in southern Thailand. Clinical data, genome information, and average nucleotide identity (ANI) were analyzed for eight isolates, revealing diverse genetic profiles and novel sequence types (STs). Minimum spanning tree analysis indicated potential clonal spread of certain STs across different geographic regions. Antimicrobial resistance genes (ARGs) were detected in all isolates, with a high prevalence of genes conferring resistance to carbapenems, highlighting the challenge of antimicrobial resistance in Acinetobacter spp. infections. Mobile genetic elements (MGEs) carrying ARGs were also identified, emphasizing the role of horizontal gene transfer in spreading resistance. Evaluation of virulence-associated genes revealed a diverse range of virulence factors, including those related to biofilm formation and antibiotic resistance. However, no direct correlation was found between virulence-associated genes in Acinetobacter spp. and specific clinical outcomes, such as infection severity or patient mortality. This complexity suggests that factors beyond gene presence may influence disease progression and outcomes. This study emphasizes the importance of continued surveillance and molecular epidemiological studies to combat the spread of multidrug-resistant (MDR) Acinetobacter non-baumannii strains. The findings provide valuable insights into the epidemiology and genetic characteristics of this bacteria in southern Thailand, with implications for infection control and antimicrobial management efforts.
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Affiliation(s)
- Thunchanok Yaikhan
- Department of Biomedical Sciences and Biomedical Engineering, Faculty of Medicine, Prince of Songkla University, Songkhla 90110, Thailand
| | - Arnon Chukamnerd
- Division of Infectious Diseases, Department of Internal Medicine, Faculty of Medicine, Prince of Songkla University, Songkhla 90110, Thailand
| | - Kamonnut Singkhamanan
- Department of Biomedical Sciences and Biomedical Engineering, Faculty of Medicine, Prince of Songkla University, Songkhla 90110, Thailand
| | - Natakorn Nokchan
- Department of Biomedical Sciences and Biomedical Engineering, Faculty of Medicine, Prince of Songkla University, Songkhla 90110, Thailand
| | - Nutwadee Chintakovid
- Department of Biomedical Sciences and Biomedical Engineering, Faculty of Medicine, Prince of Songkla University, Songkhla 90110, Thailand
| | - Sarunyou Chusri
- Division of Infectious Diseases, Department of Internal Medicine, Faculty of Medicine, Prince of Songkla University, Songkhla 90110, Thailand
| | - Rattanaruji Pomwised
- Division of Biological Science, Faculty of Science, Prince of Songkla University, Songkhla 90110, Thailand
| | - Monwadee Wonglapsuwan
- Division of Biological Science, Faculty of Science, Prince of Songkla University, Songkhla 90110, Thailand
| | - Komwit Surachat
- Department of Biomedical Sciences and Biomedical Engineering, Faculty of Medicine, Prince of Songkla University, Songkhla 90110, Thailand
- Translational Medicine Research Center, Faculty of Medicine, Prince of Songkla University, Songkhla 90110, Thailand
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Kang Y, Yu K, Huang Z, Pang B, Liu S, Peng T, Li Y, Wang D. Prevalence and molecular characteristics of Shewanella infection in diarrhea patients in Beijing, China 2017-2019. Front Microbiol 2024; 15:1293577. [PMID: 38357347 PMCID: PMC10866003 DOI: 10.3389/fmicb.2024.1293577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 01/03/2024] [Indexed: 02/16/2024] Open
Abstract
Introduction Shewanella is an important opportunistic pathogen distributed in marine environments that has caused an increasing number of clinical infections. However, there are few reports on the distribution and characteristics of Shewanella in the diarrheal pathogen spectrum. In this study, we have systematically described the prevalence of Shewanella infections in diarrhea patients in Beijing, China 2017-2019, and genome characteristics and antimicrobial susceptibility of Shewanella isolates. Methods Stool samples were collected from diarrhea patients in a surveillance project from 2017 to 2019. Shewanella strains were isolated, and identified using VITEKR 2 COMPACT and MALDI-TOF MS. Average nucleotide identity (ANI) analysis, multi-locus sequence typing (MLST), phylogenetic analysis, virulence-associated genes and antimicrobial resistance genes analysis were used for genome characteristics description. The antibiotic susceptibility test was performed with microbroth dilution method. Results 1104 fecal samples were collected, and the Shewanella detection rate was 2.36% (26/1104). The main manifestations of infection caused by Shewanella spp. were diarrhea (100%, 26/26), abdominal pain (65.38%, 17/26), and vomiting (38.46%, 10/26). The 26 isolates were classified into 3 species (S. algae (n = 18), S. indica (n = 5), and S. chilikensis (n = 3)) and 22 sequence types. Core genome single nucleotide polymorphism-based evolutionary tree identified three clone groups corresponding to three infection events in the same months in 2017 and 2019. The putative virulence-associated gene pool consisted of 56 potential virulence genes, including 19 virulence gene factors. The resistance rates of the 26 isolates to 17 antibiotics from high to low were as follows: polymyxin E (76.92%), cefotaxime (57.69%), ampicillin (50%), ampicillin-sulbactam (34.62%), nalidixic acid (15.38%), ciprofloxacin (11.54%), selectrin (3.846%,1/26), and tetracycline (3.846%, 1/26). The rate of multidrug resistance was 38.46% (10/26). Discussion Monitoring for Shewanella spp. should be added to the routine surveillance of infectious diarrhea during the epidemic season.
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Affiliation(s)
- Ying Kang
- Shunyi District Center for Disease Control and Prevention, Beijing, China
- Workstation for Microbial Infectious Disease, Shunyi District Center for Disease Control and Prevention, Beijing, China
| | - Keyi Yu
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention (China CDC), Beijing, China
| | - Zhenzhou Huang
- Hangzhou Center for Disease Control and Prevention, Hangzhou, Zhejiang, China
| | - Bo Pang
- Workstation for Microbial Infectious Disease, Shunyi District Center for Disease Control and Prevention, Beijing, China
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention (China CDC), Beijing, China
| | - Shengtian Liu
- Shunyi District Center for Disease Control and Prevention, Beijing, China
| | - Tao Peng
- Shunyi District Center for Disease Control and Prevention, Beijing, China
| | - Ying Li
- Shunyi District Center for Disease Control and Prevention, Beijing, China
- Workstation for Microbial Infectious Disease, Shunyi District Center for Disease Control and Prevention, Beijing, China
| | - Duochun Wang
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention (China CDC), Beijing, China
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Kho ZY, Azad MAK, Zhu Y, Han ML, Zhou QT, Velkov T, Naderer T, Li J. Transcriptomic interplay between Acinetobacter baumannii , human macrophage and polymyxin. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.23.576770. [PMID: 38328180 PMCID: PMC10849618 DOI: 10.1101/2024.01.23.576770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Optimization of antibiotic therapy has been hindered by our dearth of understanding on the mechanism of the host-pathogen-drug interactions. Here, we employed dual RNA-sequencing to examine transcriptomic perturbations in response to polymyxin B in a co-culture infection model of Acinetobacter baumannii and human macrophages. Our findings revealed that polymyxin B treatment induced significant transcriptomic response in macrophage-interacting A. baumannii , exacerbating bacterial oxidative stress, disrupting metal homeostasis, affecting osmoadaptation, triggering stringent stress response, and influencing pathogenic factors. Moreover, infected macrophages adapt heme catabolism, coagulation cascade, and hypoxia-inducible signaling to confront bacterial invasion. Disrupting rcnB , ompW , and traR/dksA genes in A. baumannii impairs metal homeostasis, osmotic stress defense and stringent responses, thereby enhancing antibacterial killing by polymyxin. These findings shed light on the global stress adaptations at the network level during host-pathogen-drug interactions, revealing promising therapeutic targets for further investigation. IMPORTANCE In the context of the development of bacterial resistance during the course of antibiotic therapy, the role of macrophages in shaping bacterial response to antibiotic killing remains enigmatic. Herein we employed dual RNA-sequencing and an in vitro tripartite model to delve into the unexplored transcriptional networks of the Acinetobacter baumannii -macrophage-polymyxin axis. Our findings uncovered the potential synergy between macrophages and polymyxin B which appear to act in co-operation to disrupt multiple stress tolerance mechanisms in A. baumannii . Notably, we discovered the critical roles of bacterial nickel/cobalt homeostasis ( rcnB family), osmotic stress defense ( ompW family), and stringent response regulator ( traR/dksA C4-type zinc finger) in tolerating the last-line antibiotic polymyxin B. Our findings may lead to potential targets for the development of novel therapeutics against the problematic pathogen A. baumannii .
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Shi J, Cheng J, Liu S, Zhu Y, Zhu M. Acinetobacter baumannii: an evolving and cunning opponent. Front Microbiol 2024; 15:1332108. [PMID: 38318341 PMCID: PMC10838990 DOI: 10.3389/fmicb.2024.1332108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 01/08/2024] [Indexed: 02/07/2024] Open
Abstract
Acinetobacter baumannii is one of the most common multidrug-resistant pathogens causing nosocomial infections. The prevalence of multidrug-resistant A. baumannii infections is increasing because of several factors, including unregulated antibiotic use. A. baumannii drug resistance rate is high; in particular, its resistance rates for tigecycline and polymyxin-the drugs of last resort for extensively drug-resistant A. baumannii-has been increasing annually. Patients with a severe infection of extensively antibiotic-resistant A. baumannii demonstrate a high mortality rate along with a poor prognosis, which makes treating them challenging. Through carbapenem enzyme production and other relevant mechanisms, A. baumannii has rapidly acquired a strong resistance to carbapenem antibiotics-once considered a class of strong antibacterials for A. baumannii infection treatment. Therefore, understanding the resistance mechanism of A. baumannii is particularly crucial. This review summarizes mechanisms underlying common antimicrobial resistance in A. baumannii, particularly those underlying tigecycline and polymyxin resistance. This review will serve as a reference for reasonable antibiotic use at clinics, as well as new antibiotic development.
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Affiliation(s)
- Jingchao Shi
- Open Laboratory Medicine, Hangzhou Xixi Hospital Affiliated to Zhejiang Chinese Medical University, Hangzhou, China
- Department of Clinical Laboratory, Affiliated Jinhua Hospital, Zhejiang University School of Medicine, Jinhua, China
- Graduate School, Zhejiang Chinese Medical University, Hangzhou, China
| | - Jianghao Cheng
- Open Laboratory Medicine, Hangzhou Xixi Hospital Affiliated to Zhejiang Chinese Medical University, Hangzhou, China
| | - Shourong Liu
- Department of Infectious Disease, Hangzhou Xixi Hospital Affiliated to Zhejiang Chinese Medical University, Hangzhou, China
| | - Yufeng Zhu
- Open Laboratory Medicine, Hangzhou Xixi Hospital Affiliated to Zhejiang Chinese Medical University, Hangzhou, China
| | - Mingli Zhu
- Open Laboratory Medicine, Hangzhou Xixi Hospital Affiliated to Zhejiang Chinese Medical University, Hangzhou, China
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Abdul-Mutakabbir JC, Opoku NS, Tan KK, Jorth P, Nizet V, Fletcher HM, Kaye KS, Rybak MJ. Determining Susceptibility and Potential Mediators of Resistance for the Novel Polymyxin Derivative, SPR206, in Acinetobacter baumannii. Antibiotics (Basel) 2024; 13:47. [PMID: 38247606 PMCID: PMC10812597 DOI: 10.3390/antibiotics13010047] [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: 12/12/2023] [Revised: 12/30/2023] [Accepted: 01/02/2024] [Indexed: 01/23/2024] Open
Abstract
With the increase in carbapenem-resistant A. baumannii (CRAB) infections, there has been a resurgence in the use of polymyxins, specifically colistin (COL). Since the reintroduction of COL-based regimens in treating CRAB infections, several COL-resistant A. baumannii isolates have been identified, with the mechanism of resistance heavily linked with the loss of the lipopolysaccharide (LPS) layer of the bacterial outer membrane through mutations in lpxACD genes or the pmrCAB operon. SPR206, a novel polymyxin derivative, has exhibited robust activity against multidrug-resistant (MDR) A. baumannii. However, there is a dearth of knowledge regarding its efficacy in comparison with other A. baumannii-active therapeutics and whether traditional polymyxin (COL) mediators of A. baumannii resistance also translate to reduced SPR206 activity. Here, we conducted susceptibility testing using broth microdilution on 30 A. baumannii isolates (17 COL-resistant and 27 CRAB), selected 14 COL-resistant isolates for genomic sequencing analysis, and performed time-kill analyses on four COL-resistant isolates. In susceptibility testing, SPR206 demonstrated a lower range of minimum inhibitory concentrations (MICs) compared with COL, with a four-fold difference observed in MIC50 values. Mutations in lpxACD and/or pmrA and pmrB genes were detected in each of the 14 COL-resistant isolates; however, SPR206 maintained MICs ≤ 2 mg/L for 9/14 (64%) of the isolates. Finally, SPR206-based combination regimens exhibited increased synergistic and bactericidal activity compared with COL-based combination regimens irrespective of the multiple resistance genes detected. The results of this study highlight the potential utility of SPR206 in the treatment of COL-resistant A. baumannii infections.
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Affiliation(s)
- Jacinda C. Abdul-Mutakabbir
- Division of Clinical Pharmacy, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093, USA;
- Division of the Black Diaspora and African American Studies, University of California San Diego, La Jolla, CA 92093, USA
- Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA 92374, USA; (N.S.O.); (H.M.F.)
| | - Nana Sakyi Opoku
- Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA 92374, USA; (N.S.O.); (H.M.F.)
| | - Karen K. Tan
- Department of Pharmacy, Loma Linda University Medical Center, Loma Linda, CA 92374, USA;
| | - Peter Jorth
- Department of Pathology and Laboratory Medicine, Cedars Sinai Medical Center, Los Angeles, CA 90048, USA;
| | - Victor Nizet
- Division of Clinical Pharmacy, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093, USA;
| | - Hansel M. Fletcher
- Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA 92374, USA; (N.S.O.); (H.M.F.)
| | - Keith S. Kaye
- Department of Medicine, Rutgers University School of Medicine, New Brunswick, NJ 08854, USA;
| | - Michael J. Rybak
- Department of Pharmacy Practice, Anti-Infective Research Laboratory, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USA;
- Department of Medicine, Division of Infectious Diseases, Wayne State University, Detroit, MI 48201, USA
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Storek KM, Sun D, Rutherford ST. Inhibitors targeting BamA in gram-negative bacteria. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119609. [PMID: 37852326 DOI: 10.1016/j.bbamcr.2023.119609] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 06/08/2023] [Accepted: 09/19/2023] [Indexed: 10/20/2023]
Abstract
Antibiotic resistance has led to an increase in the number of patient hospitalizations and deaths. The situation for gram-negative bacteria is especially dire as the last new class of antibiotics active against these bacteria was introduced to the clinic over 60 years ago, thus there is an immediate unmet need for new antibiotic classes able to overcome resistance. The outer membrane, a unique and essential structure in gram-negative bacteria, contains multiple potential antibacterial targets including BamA, an outer membrane protein that folds and inserts transmembrane β-barrel proteins. BamA is essential and conserved, and its outer membrane location eliminates a barrier that molecules must overcome to access this target. Recently, antibacterial small molecules, natural products, peptides, and antibodies that inhibit BamA activity have been reported, validating the druggability of this target and generating potential leads for antibiotic development. This review will describe these BamA inhibitors, highlight their key attributes, and identify challenges with this potential target.
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Affiliation(s)
- Kelly M Storek
- Department of Infectious Diseases, Genentech Inc., South San Francisco, CA, USA
| | - Dawei Sun
- Department of Structural Biology, Genentech Inc., South San Francisco, CA, USA
| | - Steven T Rutherford
- Department of Infectious Diseases, Genentech Inc., South San Francisco, CA, USA.
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Bulitta JB, Shin E, Bergen PJ, Lang Y, Forrest A, Tsuji BT, Moya B, Li J, Nation RL, Landersdorfer CB. Distinguishing Inducible and Non-Inducible Resistance to Colistin in Pseudomonas aeruginosa by Quantitative and Systems Pharmacology Modeling at Low and Standard Inocula. J Pharm Sci 2024; 113:202-213. [PMID: 37879409 DOI: 10.1016/j.xphs.2023.10.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 10/20/2023] [Accepted: 10/20/2023] [Indexed: 10/27/2023]
Abstract
Colistin is a polymyxin and peptide antibiotic that can yield rapid bacterial killing, but also leads to resistance emergence. We aimed to develop a novel experimental and Quantitative and Systems Pharmacology approach to distinguish between inducible and non-inducible resistance. Viable count profiles for the total and less susceptible populations of Pseudomonas aeruginosa ATCC 27853 from static and dynamic in vitro infection models were simultaneously modeled. We studied low and normal initial inocula to distinguish between inducible and non-inducible resistance. A novel cutoff filter approach allowed us to describe the eradication and inter-conversion of bacterial populations. At all inocula, 4.84 mg/L of colistin (sulfate) yielded ≥4 log10 killing, followed by >4 log10 regrowth. A pre-existing, less susceptible population was present at standard but not at low inocula. Formation of a non-pre-existing, less susceptible population was most pronounced at intermediate colistin (sulfate) concentrations (0.9 to 5 mg/L). Both less susceptible populations inter-converted with the susceptible population. Simultaneously modeling of the total and less susceptible populations at low and standard inocula enabled us to identify the de novo formation of an inducible, less susceptible population. Inducible resistance at intermediate colistin concentrations highlights the importance of rapidly achieving efficacious polymyxin concentrations by front-loaded dosage regimens.
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Affiliation(s)
- Jürgen B Bulitta
- Department of Pharmacotherapy and Translational Research, College of Pharmacy, University of Florida, Orlando, FL, USA.
| | - Eunjeong Shin
- Department of Pharmacotherapy and Translational Research, College of Pharmacy, University of Florida, Orlando, FL, USA
| | - Phillip J Bergen
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), Parkville, Australia
| | - Yinzhi Lang
- Department of Pharmacotherapy and Translational Research, College of Pharmacy, University of Florida, Orlando, FL, USA
| | - Alan Forrest
- School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, SUNY, Buffalo, NY, USA
| | - Brian T Tsuji
- School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, SUNY, Buffalo, NY, USA
| | - Bartolome Moya
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitario Son Espases, Instituto de Investigación Sanitaria Illes Balears (IdISBa), Palma de Mallorca, Spain
| | - Jian Li
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), Parkville, Australia; Biomedicine Discovery Institute, Infection Program, Department of Microbiology and Department of Pharmacology, Monash University, Melbourne, Australia
| | - Roger L Nation
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), Parkville, Australia
| | - Cornelia B Landersdorfer
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), Parkville, Australia
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Abstract
Gram-negative bacteria are intrinsically resistant to many antibiotics, due in large part to the permeability barrier formed by their cell envelope. The complex and synergistic interplay of the two Gram-negative membranes and active efflux prevents the accumulation of a diverse range of compounds that are effective against Gram-positive bacteria. A lack of detailed information on how components of the cell envelope contribute to this has been identified as a key barrier to the rational development of new antibiotics with efficacy against Gram-negative species. This review describes the current understanding of the role of the different components of the Gram-negative cell envelope in preventing compound accumulation and the state of efforts to describe properties that allow compounds to overcome this barrier and apply them to the development of new broad-spectrum antibiotics.
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Affiliation(s)
- Claire Maher
- College of Engineering, Science and Environment, University of Newcastle, Newcastle, Australia
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, Australia
| | - Karl A. Hassan
- College of Engineering, Science and Environment, University of Newcastle, Newcastle, Australia
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, Australia
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Anurag Anand A, Amod A, Anwar S, Sahoo AK, Sethi G, Samanta SK. A comprehensive guide on screening and selection of a suitable AMP against biofilm-forming bacteria. Crit Rev Microbiol 2023:1-20. [PMID: 38102871 DOI: 10.1080/1040841x.2023.2293019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 11/30/2023] [Indexed: 12/17/2023]
Abstract
Lately, antimicrobial resistance (AMR) is increasing at an exponential rate making it important to search alternatives to antibiotics in order to combat multi-drug resistant (MDR) bacterial infections. Out of the several antibacterial and antibiofilm strategies being tested, antimicrobial peptides (AMPs) have shown to give better hopes in terms of a long-lasting solution to the problem. To select a desired AMP, it is important to make right use of available tools and databases that aid in identification, classification, and analysis of the physiochemical properties of AMPs. To identify the targets of these AMPs, it becomes crucial to understand their mode-of-action. AMPs can also be used in combination with other antibacterial and antibiofilm agents so as to achieve enhanced efficacy against bacteria and their biofilms. Due to concerns regarding toxicity, stability, and bioavailability, strategizing drug formulation at an early-stage becomes crucial. Although there are few concerns regarding development of bacterial resistance to AMPs, the evolution of resistance to AMPs occurs extremely slowly. This comprehensive review gives a deep insight into the selection of the right AMP, deciding the right target and combination strategy along with the type of formulation needed, and the possible resistance that bacteria can develop to these AMPs.
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Affiliation(s)
- Ananya Anurag Anand
- Department of Applied Sciences, Indian Institute of Information Technology Allahabad, Prayagraj, India
| | - Ayush Amod
- Department of Applied Sciences, Indian Institute of Information Technology Allahabad, Prayagraj, India
| | - Sarfraz Anwar
- Department of Bioinformatics, University of Allahabad, Prayagraj, India
| | - Amaresh Kumar Sahoo
- Department of Applied Sciences, Indian Institute of Information Technology Allahabad, Prayagraj, India
| | - Gautam Sethi
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Sintu Kumar Samanta
- Department of Applied Sciences, Indian Institute of Information Technology Allahabad, Prayagraj, India
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Gómez AC, Horgan C, Yero D, Bravo M, Daura X, O'Driscoll M, Gibert I, O'Sullivan TP. Synthesis and evaluation of aromatic BDSF bioisosteres on biofilm formation and colistin sensitivity in pathogenic bacteria. Eur J Med Chem 2023; 261:115819. [PMID: 37748387 DOI: 10.1016/j.ejmech.2023.115819] [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: 08/14/2023] [Revised: 09/11/2023] [Accepted: 09/12/2023] [Indexed: 09/27/2023]
Abstract
The diffusible signal factor family (DSF) of molecules play an important role in regulating intercellular communication, or quorum sensing, in several disease-causing bacteria. These messenger molecules, which are comprised of cis-unsaturated fatty acids, are involved in the regulation of biofilm formation, antibiotic tolerance, virulence and the control of bacterial resistance. We have previously demonstrated how olefinic N-acyl sulfonamide bioisosteric analogues of diffusible signal factor can reduce biofilm formation or enhance antibiotic sensitivity in a number of bacterial strains. This work describes the design and synthesis of a second generation of aromatic N-acyl sulfonamide bioisosteres. The impact of these compounds on biofilm production in Acinetobacter baumannii, Escherichia coli, Burkholderia multivorans, Burkholderia cepacia, Burkholderia cenocepacia, Pseudomonas aeruginosa and Stenotrophomonas maltophilia is evaluated, in addition to their effects on antibiotic tolerance. The ability of these molecules to increase survival rates on co-administration with colistin is also investigated using the Galleria infection model.
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Affiliation(s)
- Andromeda-Celeste Gómez
- Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona, Barcelona, Spain; Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Conor Horgan
- School of Chemistry, University College Cork, Cork, Ireland
| | - Daniel Yero
- Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona, Barcelona, Spain; Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Marc Bravo
- Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona, Barcelona, Spain; Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Xavier Daura
- Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona, Barcelona, Spain; Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain; CIBER de Bioingeniería, Biomateriales y Nanomedicina, Instituto de Salud Carlos III, Cerdanyola de Vallès, Spain
| | - Michelle O'Driscoll
- School of Chemistry, University College Cork, Cork, Ireland; School of Pharmacy, University College Cork, Cork, Ireland; Analytical and Biological Chemistry Research Facility, University College Cork, Cork, Ireland
| | - Isidre Gibert
- Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona, Barcelona, Spain; Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona, Barcelona, Spain.
| | - Timothy P O'Sullivan
- School of Chemistry, University College Cork, Cork, Ireland; School of Pharmacy, University College Cork, Cork, Ireland; Analytical and Biological Chemistry Research Facility, University College Cork, Cork, Ireland.
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41
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Ji X, Yu R, Zhu M, Zhang C, Zhou L, Cai T, Li W. Diadenosine tetraphosphate modulated quorum sensing in bacteria treated with kanamycin. BMC Microbiol 2023; 23:353. [PMID: 37978430 PMCID: PMC10657157 DOI: 10.1186/s12866-023-03113-3] [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: 09/14/2023] [Accepted: 11/06/2023] [Indexed: 11/19/2023] Open
Abstract
BACKGROUND The dinucleotide alarmone diadenosine tetraphosphate (Ap4A), which is found in cells, has been shown to affect the survival of bacteria under stress. RESULTS Here, we labeled Ap4A with biotin and incubated the labeled Ap4A with the total proteins extracted from kanamycin-treated Escherichia coli to identify the Ap4A binding protein in bacteria treated with kanamycin. Liquid chromatography‒mass spectrometry (LCMS) and bioinformatics were used to identify novel proteins that Ap4A interacts with that are involved in biofilm formation, quorum sensing, and lipopolysaccharide biosynthesis pathways. Then, we used the apaH knockout strain of E. coli K12-MG1655, which had increased intracellular Ap4A, to demonstrate that Ap4A affected the expression of genes in these three pathways. We also found that the swarming motility of the apaH mutant strain was reduced compared with that of the wild-type strain, and under kanamycin treatment, the biofilm formation of the mutant strain decreased. CONCLUSIONS These results showed that Ap4A can reduce the survival rate of bacteria treated with kanamycin by regulating quorum sensing (QS). These effects can expand the application of kanamycin combinations in the treatment of multidrug-resistant bacteria.
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Affiliation(s)
- Xia Ji
- School of Life Science, Huizhou University, Huizhou, 516007, China.
| | - Ruojing Yu
- School of Life Science, Huizhou University, Huizhou, 516007, China
| | - Meilian Zhu
- School of Life Science, Huizhou University, Huizhou, 516007, China
| | - Cuilin Zhang
- School of Life Science, Huizhou University, Huizhou, 516007, China
| | - Libin Zhou
- School of Life Science, Huizhou University, Huizhou, 516007, China
| | - Tianshu Cai
- Huizhou Health Sciences Polytechnic, Huizhou, 516025, China
| | - Weiwei Li
- Huizhou Health Sciences Polytechnic, Huizhou, 516025, China
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42
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Chen Y, Yong M, Li M, Si Z, Koh CH, Lau P, Chang YW, Teo J, Chan-Park MB, Gan YH. A hydrophilic polyimidazolium antibiotic targeting the membranes of Gram-negative bacteria. J Antimicrob Chemother 2023; 78:2581-2590. [PMID: 37671807 PMCID: PMC10545527 DOI: 10.1093/jac/dkad274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 08/21/2023] [Indexed: 09/07/2023] Open
Abstract
OBJECTIVES The rise of MDR Gram-negative bacteria (GNB), especially those resistant to last-resort drugs such as carbapenems and colistin, is a global health risk and calls for increased efforts to discover new antimicrobial compounds. We previously reported that polyimidazolium (PIM) compounds exhibited significant antimicrobial activity and minimal mammalian cytotoxicity. However, their mechanism of action is relatively unknown. We examined the efficacy and mechanism of action of a hydrophilic PIM (PIM5) against colistin- and meropenem-resistant clinical isolates. METHODS MIC and time-kill testing was performed for drug-resistant Escherichia coli and Klebsiella pneumoniae clinical isolates. N-phenyl-1-naphthylamine and propidium iodide dyes were employed to determine membrane permeabilization. Spontaneous resistant mutants and single deletion mutants were generated to understand potential resistance mechanisms to the drug. RESULTS PIM5 had the same effectiveness against colistin- and meropenem-resistant strains as susceptible strains of GNB. PIM5 exhibited a rapid bactericidal effect independent of bacterial growth phase and was especially effective in water. The polymer disrupts both the outer and cytoplasmic membranes. PIM5 binds and intercalates into bacterial genomic DNA upon entry of cells. GNB do not develop high resistance to PIM5. However, the susceptibility and uptake of the polymer is moderately affected by mutations in the two-component histidine kinase sensor BaeS. PIM5 has negligible cytotoxicity on human cells at bacterial-killing concentrations, comparable to the commercial antibiotics polymyxin B and colistin. CONCLUSIONS PIM5 is a potent broad-spectrum antibiotic targeting GNB resistant to last-resort antibiotics.
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Affiliation(s)
- Yahua Chen
- Infectious Diseases Translational Research Programme, Department of Biochemistry, National University of Singapore, Singapore, Singapore
| | - Melvin Yong
- Infectious Diseases Translational Research Programme, Department of Biochemistry, National University of Singapore, Singapore, Singapore
| | - Ming Li
- Infectious Diseases Translational Research Programme, Department of Biochemistry, National University of Singapore, Singapore, Singapore
| | - Zhangyong Si
- School of Chemistry, Chemical and Biotechnology, Nanyang Technological University, Singapore, Singapore
| | - Chong Hui Koh
- School of Chemistry, Chemical and Biotechnology, Nanyang Technological University, Singapore, Singapore
| | - Pearlyn Lau
- Infectious Diseases Translational Research Programme, Department of Biochemistry, National University of Singapore, Singapore, Singapore
| | - Yi Wei Chang
- Infectious Diseases Translational Research Programme, Department of Biochemistry, National University of Singapore, Singapore, Singapore
| | - Jeanette Teo
- Department of Laboratory Medicine, National University Hospital, Singapore, Singapore
| | - Mary B Chan-Park
- School of Chemistry, Chemical and Biotechnology, Nanyang Technological University, Singapore, Singapore
| | - Yunn-Hwen Gan
- Infectious Diseases Translational Research Programme, Department of Biochemistry, National University of Singapore, Singapore, Singapore
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43
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Cross AS. Hit 'em Where It Hurts: Gram-Negative Bacterial Lipopolysaccharide as a Vaccine Target. Microbiol Mol Biol Rev 2023; 87:e0004522. [PMID: 37432116 PMCID: PMC10521362 DOI: 10.1128/mmbr.00045-22] [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] [Indexed: 07/12/2023] Open
Abstract
Infections with antimicrobial-resistant (AMR) bacteria pose an increasing threat to the ability to perform surgical procedures, organ transplantation, and treat cancer among many other medical conditions. There are few new antimicrobials in the development pipeline. Vaccines against AMR Gram-negative bacteria may reduce the use of antimicrobials and prevent bacterial transmission. This review traces the origins of lipopolysaccharide (LPS)-based vaccines against Gram-negative bacteria, the role of O polysaccharides and LPS core regions as potential vaccine targets, the development of new vaccine technologies, and their application to vaccines in current development.
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Affiliation(s)
- Alan S. Cross
- Center for Vaccine Development and Global Health, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
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44
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Noel HR, Keerthi S, Ren X, Winkelman JD, Troutman JM, Palmer LD. Genetic synergy in Acinetobacter baumannii undecaprenyl biosynthesis and maintenance of lipid asymmetry impacts outer membrane and antimicrobial resistance. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.22.556980. [PMID: 37790371 PMCID: PMC10542541 DOI: 10.1101/2023.09.22.556980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Acinetobacter baumannii is a Gram-negative healthcare-associated pathogen that poses a major health concern due to increasing multidrug resistance. The Gram-negative cell envelope is a key barrier to antimicrobial entry and includes an inner and outer membrane. The outer membrane has an asymmetric composition that is important for structural integrity and barrier to the environment. Therefore, Gram-negative bacteria have mechanisms to uphold this asymmetry such as the maintenance of lipid asymmetry system (Mla), which removes glycerophospholipids from the outer leaflet of the outer membrane and transports them to the inner membrane. Loss of this system in A. baumannii results in attenuated virulence and increased susceptibility to membrane stressors and some antibiotics. We recently reported two strain variants of the A. baumannii type strain ATCC 17978, 17978VU and 17978UN. We show here that ΔmlaF mutants in the two strains display different phenotypes for membrane stress resistance, antibiotic resistance, and pathogenicity in a murine pneumonia model. We used comparative genetics to identify interactions between ATCC 17978 strain alleles and mlaF to uncover the cause behind the phenotypic differences. Although allele differences in obgE were previously reported to synergize with ΔmlaF to affect growth and stringent response, we show that obgE alleles do not affect membrane stress resistance. Instead, a single nucleotide polymorphism (SNP) in the essential gene encoding undecaprenyl pyrophosphate (Und-PP) synthase, uppS, synergizes with ΔmlaF to increase susceptibility to membrane stress and antibiotics, and reduce persistence in a mouse lung infection. Und-P is a lipid glycan carrier known to be required for biosynthesis of A. baumannii capsule, cell wall, and glycoproteins. Our data suggest that in the absence of the Mla system, the cellular level of Und-P is critical for envelope integrity, antibiotic resistance, and lipooligosaccharide abundance. These findings uncover synergy between Und-P and the Mla system in maintaining the A. baumannii outer membrane and stress resistance.
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Affiliation(s)
- Hannah R. Noel
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, IL, USA
| | - Sowmya Keerthi
- Department of Chemistry, University of North Carolina Charlotte, Charlotte, NC, USA
| | - Xiaomei Ren
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, IL, USA
| | | | - Jerry M. Troutman
- Department of Chemistry, University of North Carolina Charlotte, Charlotte, NC, USA
| | - Lauren D. Palmer
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, IL, USA
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45
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Gadar K, de Dios R, Kadeřábková N, Prescott TAK, Mavridou DAI, McCarthy RR. Disrupting iron homeostasis can potentiate colistin activity and overcome colistin resistance mechanisms in Gram-Negative Bacteria. Commun Biol 2023; 6:937. [PMID: 37704838 PMCID: PMC10499790 DOI: 10.1038/s42003-023-05302-2] [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: 01/26/2023] [Accepted: 08/29/2023] [Indexed: 09/15/2023] Open
Abstract
Acinetobacter baumannii is a Gram-negative priority pathogen that can readily overcome antibiotic treatment through a range of intrinsic and acquired resistance mechanisms. Treatment of carbapenem-resistant A. baumannii largely relies on the use of colistin in cases where other treatment options have been exhausted. However, the emergence of resistance against this last-line drug has significantly increased amongst clinical strains. In this study, we identify the phytochemical kaempferol as a potentiator of colistin activity. When administered singularly, kaempferol has no effect on growth but does impact biofilm formation. Nonetheless, co-administration of kaempferol with sub-inhibitory concentrations of colistin exposes bacteria to a metabolic Achilles heel, whereby kaempferol-induced dysregulation of iron homeostasis leads to bacterial killing. We demonstrate that this effect is due to the disruption of Fenton's reaction, and therefore to a lethal build-up of toxic reactive oxygen species in the cell. Furthermore, we show that this vulnerability can be exploited to overcome both intrinsic and acquired colistin resistance in clinical strains of A. baumannii and E. coli in vitro and in the Galleria mellonella model of infection. Overall, our findings provide a proof-of-principle demonstration that targeting iron homeostasis is a promising strategy for enhancing the efficacy of colistin and overcoming colistin-resistant infections.
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Affiliation(s)
- Kavita Gadar
- Biosciences, Department of Life Sciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, UB8 3PH, UK
| | - Rubén de Dios
- Biosciences, Department of Life Sciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, UB8 3PH, UK
| | - Nikol Kadeřábková
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, 78712, USA
| | | | - Despoina A I Mavridou
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, 78712, USA
- John Ring LaMontagne Centre for Infectious Diseases, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Ronan R McCarthy
- Biosciences, Department of Life Sciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, UB8 3PH, UK.
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46
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Fan Z, Fu T, Liu H, Li Z, Du B, Cui X, Zhang R, Feng Y, Zhao H, Xue G, Cui J, Yan C, Gan L, Feng J, Xu Z, Yu Z, Tian Z, Ding Z, Chen J, Chen Y, Yuan J. Glucose Induces Resistance to Polymyxins in High-Alcohol-Producing Klebsiella pneumoniae via Increasing Capsular Polysaccharide and Maintaining Intracellular ATP. Microbiol Spectr 2023; 11:e0003123. [PMID: 37338347 PMCID: PMC10434286 DOI: 10.1128/spectrum.00031-23] [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: 01/10/2023] [Accepted: 05/31/2023] [Indexed: 06/21/2023] Open
Abstract
High-alcohol-producing K. pneumoniae (HiAlc Kpn) causes nonalcoholic fatty liver disease (NAFLD) by producing excess endogenous alcohol in the gut of patients with NAFLD, using glucose as the main carbon source. The role of glucose in the response of HiAlc Kpn to environmental stresses such as antibiotics remains unclear. In this study, we found that glucose could enhance the resistance of HiAlc Kpn to polymyxins. First, glucose inhibited the expression of crp in HiAlc Kpn and promoted the increase of capsular polysaccharide (CPS), which promoted the drug resistance of HiAlc Kpn. Second, glucose maintained high ATP levels in HiAlc Kpn cells under the pressure of polymyxins, enhancing the resistance of the cells to the killing effect of antibiotics. Notably, the inhibition of CPS formation and the decrease of intracellular ATP levels could both effectively reverse glucose-induced polymyxins resistance. Our work demonstrated the mechanism by which glucose induces polymyxins resistance in HiAlc Kpn, thereby laying the foundation for developing effective treatments for NAFLD caused by HiAlc Kpn. IMPORTANCE HiAlc Kpn can use glucose to produce excess endogenous alcohol for promoting the development of NAFLD. Polymyxins are the last line of antibiotics and are commonly used to treat infections caused by carbapenem-resistant K. pneumoniae. In this study, we found that glucose increased bacterial resistance to polymyxins via increasing CPS and maintaining intracellular ATP; this increases the risk of failure to treat NAFLD caused by multidrug-resistant HiAlc Kpn infection. Further research revealed the important roles of glucose and the global regulator, CRP, in bacterial resistance and found that inhibiting CPS formation and decreasing intracellular ATP levels could effectively reverse glucose-induced polymyxins resistance. Our work reveals that glucose and the regulatory factor CRP can affect the resistance of bacteria to polymyxins, laying a foundation for the treatment of infections caused by multidrug-resistant bacteria.
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Affiliation(s)
- Zheng Fan
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Tongtong Fu
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Hongbo Liu
- School of Pharmaceutical Sciences, Jilin University, Changchun, China
| | - Zhoufei Li
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Bing Du
- University of Edinburgh, Edinburgh, United Kingdom
| | - Xiaohu Cui
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Rui Zhang
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
- Graduate School, Peking Union Medical College, Beijing, China
| | - Yanling Feng
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Hanqing Zhao
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Guanhua Xue
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Jinghua Cui
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Chao Yan
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Lin Gan
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Junxia Feng
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Ziying Xu
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Zihui Yu
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Ziyan Tian
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Zanbo Ding
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Jinfeng Chen
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Yujie Chen
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Jing Yuan
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
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47
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Paredes-Amaya CC, Ulloa MT, García-Angulo VA. Fierce poison to others: the phenomenon of bacterial dependence on antibiotics. J Biomed Sci 2023; 30:67. [PMID: 37574554 PMCID: PMC10424368 DOI: 10.1186/s12929-023-00963-x] [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: 04/25/2023] [Accepted: 08/07/2023] [Indexed: 08/15/2023] Open
Abstract
Beyond the development of resistance, the effects of antibiotics on bacteria and microbial communities are complex and far from exhaustively studied. In the context of the current global antimicrobial resistance crisis, understanding the adaptive and physiological responses of bacteria to antimicrobials is of paramount importance along with the development of new therapies. Bacterial dependence on antibiotics is a phenomenon in which antimicrobials instead of eliminating the pathogens actually provide a boost for their growth. This trait comprises an extreme example of the complexities of responses elicited by microorganisms to these drugs. This compelling evolutionary trait was readily described along with the first wave of antibiotics use and dependence to various antimicrobials has been reported. Nevertheless, current molecular characterizations have been focused on dependence on vancomycin, linezolid and colistin, three critically important antibiotics frequently used as last resource therapy for multi resistant pathogens. Outstanding advances have been made in understanding the molecular basis for the dependence to vancomycin, including specific mutations involved. Regarding linezolid and colistin, the general physiological components affected by the dependence, namely ribosomes and membrane function respectively, have been established. Nonetheless the implications of antibiotic dependence in clinically relevant features, such as virulence, epidemics, relationship with development of resistance, diagnostics and therapy effectiveness require clarification. This review presents a brief introduction of the phenomenon of bacterial dependence to antibiotics and a summary on early and current research concerning the basis for this trait. Furthermore, the available information on the effect of dependence in key clinical aspects is discussed. The studies performed so far underline the need to fully disclose the biological and clinical significance of this trait in pathogens to successfully assess its role in resistance and to design adjusted therapies.
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Affiliation(s)
- Claudia C Paredes-Amaya
- Microbiology Department, Escuela de Ciencias Básicas, Facultad de Salud, Universidad del Valle, Cali, Colombia
| | - María Teresa Ulloa
- Microbiology and Micology Program, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Independencia 1027, Independencia, RM, Santiago, Chile
- Vertebral I+D+i - Corporation for Assistance for Burned Children (Coaniquem), Santiago, Chile
| | - Víctor Antonio García-Angulo
- Microbiology and Micology Program, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Independencia 1027, Independencia, RM, Santiago, Chile.
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48
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Ding Y, Hao J, Xiao W, Ye C, Xiao X, Jian C, Tang M, Li G, Liu J, Zeng Z. Role of efflux pumps, their inhibitors, and regulators in colistin resistance. Front Microbiol 2023; 14:1207441. [PMID: 37601369 PMCID: PMC10436536 DOI: 10.3389/fmicb.2023.1207441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 07/13/2023] [Indexed: 08/22/2023] Open
Abstract
Colistin is highly promising against multidrug-resistant and extensively drug-resistant bacteria clinically. Bacteria are resistant to colistin mainly through mcr and chromosome-mediated lipopolysaccharide (LPS) synthesis-related locus variation. However, the current understanding cannot fully explain the resistance mechanism in mcr-negative colistin-resistant strains. Significantly, the contribution of efflux pumps to colistin resistance remains to be clarified. This review aims to discuss the contribution of efflux pumps and their related transcriptional regulators to colistin resistance in various bacteria and the reversal effect of efflux pump inhibitors on colistin resistance. Previous studies suggested a complex regulatory relationship between the efflux pumps and their transcriptional regulators and LPS synthesis, transport, and modification. Carbonyl cyanide 3-chlorophenylhydrazone (CCCP), 1-(1-naphthylmethyl)-piperazine (NMP), and Phe-Arg-β-naphthylamide (PAβN) all achieved the reversal of colistin resistance, highlighting the role of efflux pumps in colistin resistance and their potential for adjuvant development. The contribution of the efflux pumps to colistin resistance might also be related to specific genetic backgrounds. They can participate in colistin tolerance and heterogeneous resistance to affect the treatment efficacy of colistin. These findings help understand the development of resistance in mcr-negative colistin-resistant strains.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Jinbo Liu
- Department of Laboratory Medicine, the Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Zhangrui Zeng
- Department of Laboratory Medicine, the Affiliated Hospital of Southwest Medical University, Luzhou, China
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49
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Ward RD, Tran JS, Banta AB, Bacon EE, Rose WE, Peters JM. Essential Gene Knockdowns Reveal Genetic Vulnerabilities and Antibiotic Sensitivities in Acinetobacter baumannii. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.02.551708. [PMID: 37577569 PMCID: PMC10418195 DOI: 10.1101/2023.08.02.551708] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
The emergence of multidrug-resistant Gram-negative bacteria underscores the need to define genetic vulnerabilities that can be therapeutically exploited. The Gram-negative pathogen, Acinetobacter baumannii, is considered an urgent threat due to its propensity to evade antibiotic treatments. Essential cellular processes are the target of existing antibiotics and a likely source of new vulnerabilities. Although A. baumannii essential genes have been identified by transposon sequencing (Tn-seq), they have not been prioritized by sensitivity to knockdown or antibiotics. Here, we take a systems biology approach to comprehensively characterize A. baumannii essential genes using CRISPR interference (CRISPRi). We show that certain essential genes and pathways are acutely sensitive to knockdown, providing a set of vulnerable targets for future therapeutic investigation. Screening our CRISPRi library against last-resort antibiotics uncovered genes and pathways that modulate beta-lactam sensitivity, an unexpected link between NADH dehydrogenase activity and growth inhibition by polymyxins, and anticorrelated phenotypes that underpin synergy between polymyxins and rifamycins. Our study demonstrates the power of systematic genetic approaches to identify vulnerabilities in Gram-negative pathogens and uncovers antibiotic-essential gene interactions that better inform combination therapies.
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Affiliation(s)
- Ryan D Ward
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI 53706
| | - Jennifer S Tran
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI 53706
| | - Amy B Banta
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53726
| | - Emily E Bacon
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI 53706
| | - Warren E Rose
- Pharmacy Practice Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705
| | - Jason M Peters
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53726
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI 53706
- Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI 53706
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50
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Hoffmann A, Pacios K, Mühlemann R, Daumke R, Frank B, Kalman F. Application of a novel chemical assay for the quantification of endotoxins in bacterial bioreactor samples. J Chromatogr B Analyt Technol Biomed Life Sci 2023; 1228:123839. [PMID: 37527605 DOI: 10.1016/j.jchromb.2023.123839] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 06/26/2023] [Accepted: 07/19/2023] [Indexed: 08/03/2023]
Abstract
A novel chemical assay, the so-called Kdo-DMB-liquid chromatography (LC) assay, was used for the accurate and cost-effective determination of the endotoxin content in supernatants of Gram-negative bacteria bioreactor samples. During mild acid hydrolysis, the endotoxin-specific sugar acid 3-deoxy-D-manno-oct-2-ulsonic acid (Kdo) is quantitatively released. Kdo is reacted with 1,2-diamino-4,5-methylenedioxybenzene (DMB) to obtain the highly fluorescent derivate Kdo-DMB. It is separated from the reaction mixture by reversed phase-(U)HPLC and detected by fluorescence. From the Kdo content the endotoxin content of the sample is calculated. For three batch cultivations of Escherichia coli K12 and a fed-batch cultivation of Pseudomonas putida KT2440, the evolution of the endotoxin content in dependence on the cultivation time was monitored. Under optimal, constant cultivation conditions a linear correlation between the endotoxin content and the easy-to-access bioreactor parameters optical density at 600 nm and dry cell weight was found for both endotoxin kinds. Under stress cultivation conditions the E. coli K12 cultivation showed a stronger increase of the endotoxin content at harvest in comparison to optimal conditions. Optical density and dry cell weight may be used for production reactors as an economic real-time estimation tool to determine the endotoxin content at different cultivation time points and conditions. The optical density can further be used to establish straightforward sample dilution schemes for endotoxin quantification in samples of unknown endotoxin content. The endotoxin content [ng mL-1] measured by the Kdo-DMB-LC assay and the endotoxin activity [EU mL-1] obtained by the compendial Limulus Amoebocyte Lysate assay show a high correlation for the bacterial bioreactor samples tested.
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Affiliation(s)
- Anika Hoffmann
- University of Applied Sciences and Arts Western Switzerland Valais, Institute of Life Technology, Rue de l'Industrie 23, 1950 Sion, Switzerland
| | - Kevin Pacios
- University of Applied Sciences and Arts Western Switzerland Valais, Institute of Life Technology, Rue de l'Industrie 23, 1950 Sion, Switzerland
| | - Reto Mühlemann
- FILTROX AG, Moosmühlestr. 6, 9000 St. Gallen, Switzerland
| | - Ralph Daumke
- FILTROX AG, Moosmühlestr. 6, 9000 St. Gallen, Switzerland
| | - Brian Frank
- FILTROX AG, Moosmühlestr. 6, 9000 St. Gallen, Switzerland
| | - Franka Kalman
- University of Applied Sciences and Arts Western Switzerland Valais, Institute of Life Technology, Rue de l'Industrie 23, 1950 Sion, Switzerland.
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