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Ghimire J, Guha S, Nelson BJ, Morici LA, Wimley WC. The Remarkable Innate Resistance of Burkholderia bacteria to Cationic Antimicrobial Peptides: Insights into the Mechanism of AMP Resistance. J Membr Biol 2022; 255:503-511. [PMID: 35435452 PMCID: PMC9576820 DOI: 10.1007/s00232-022-00232-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Accepted: 03/24/2022] [Indexed: 12/29/2022]
Abstract
Gram-negative bacteria belonging to the genus Burkholderia are remarkably resistant to broad-spectrum, cationic, antimicrobial peptides (AMPs). It has been proposed that this innate resistance is related to changes in the outer membrane lipopolysaccharide (OM LPS), including the constitutive, essential modification of outer membrane Lipid A phosphate groups with cationic 4-amino-4-deoxy-arabinose. This modification reduces the overall negative charge on the OM LPS which may change the OM structure and reduce the binding, accumulation, and permeation of cationic AMPs. Similarly, the Gram-negative pathogen Pseudomonas aeruginosa can quickly become resistant to many AMPs by multiple mechanisms, frequently, including activation of the arn operon, which leads, transiently, to the same modification of Lipid A. We recently discovered a set of synthetically evolved AMPs that do not invoke any resistance in P. aeruginosa over multiple passages and thus are apparently not inhibited by aminorabinosylation of Lipid A in P. aeruginosa. Here we test these resistance-avoiding peptides, within a set of 18 potent AMPs, against Burkholderia thailandensis. We find that none of the AMPs tested have measurable activity against B. thailandensis. Some were inactive at concentrations as high as 150 μM, despite all having sterilizing activity at ≤ 10 μM against a panel of common, human bacterial pathogens, including P. aeruginosa. We speculate that the constitutive modification of Lipid A in members of the Burkholderia genus is only part of a broader set of modifications that change the architecture of the OM to provide such remarkable levels of resistance to cationic AMPs.
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Affiliation(s)
- Jenisha Ghimire
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, 70112
| | - Shantanu Guha
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, 70112
| | - Benjamin J. Nelson
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, 70112
| | - Lisa A. Morici
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA, 70112
| | - William C. Wimley
- Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, New Orleans, LA, 70112,To whom correspondence should be addressed at
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Niu H, Yee R, Cui P, Zhang S, Tian L, Shi W, Sullivan D, Zhu B, Zhang W, Zhang Y. Identification and Ranking of Clinical Compounds with Activity Against Log-phase Growing Uropathogenic Escherichia coli. Curr Drug Discov Technol 2021; 17:191-196. [PMID: 30088449 DOI: 10.2174/1570163815666180808115501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 07/26/2018] [Accepted: 08/06/2018] [Indexed: 11/22/2022]
Abstract
BACKGROUND Uropathogenic Escherichia coli (UPEC) is a major cause of Urinary Tract Infections (UTIs). Due to increasing antibiotic-resistance among UPEC bacteria, new treatment options for UTIs are urgently needed. OBJECTIVE To identify new agents targeting growing bacteria that may be used for the treatment of antibiotic-resistant UTIs. METHODS We screened a clinical compound library consisting of 1,524 compounds using a high throughput 96-well plate assay and ranked the activities of the selected agents according to their MICs against the UPEC strain UTI89. RESULTS We identified 33 antibiotics which were active against log-phase clinical UPEC strain UTI89. Among the selected antibiotics, there were 12 fluoroquinolone antibiotics (tosufloxacin, levofloxacin, sparfloxacin, clinafloxacin, pazufloxacin, gatifloxacin, enrofloxacin, lomefloxacin, norfloxacin, fleroxacin, flumequine, ciprofloxacin), 15 beta-lactam or cephalosporin antibiotics (cefmenoxime, cefotaxime, ceftizoxime, cefotiam, cefdinir, cefoperazone, cefpiramide, cefamandole, cefixime, ceftibuten, cefmetazole, cephalosporin C, aztreonam, piperacillintazobactam, mezlocillin), 3 tetracycline antibiotics (meclocycline, doxycycline, tetracycline), 2 membrane-acting agents (colistin and clofoctol), and 1 protein synthesis inhibitor (amikacin). Among them, the top 7 hits were colistin, tosufloxacin, levofloxacin, sparfloxacin, clinafloxacin, cefmenoxime and pazufloxacin, where clinafloxacin and pazufloxacin were the newly identified agents active against UPEC strain UTI89. We validated the key results obtained with UTI89 on two other UTI strains CFT073 and KTE181 and found that they all had comparable MICs for fluoroquinolones while CFT073 and KTE181 were more susceptible to cephalosporin antibiotics and tetracycline antibiotics but were less susceptible to colistin than UTI89. CONCLUSION Our findings provide possible effective drug candidates for the more effective treatment of antibiotic-resistant UTIs.
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Affiliation(s)
- Hongxia Niu
- Lanzhou Center for Tuberculosis Research and Institute of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China.,Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, United States
| | - Rebecca Yee
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, United States
| | - Peng Cui
- Key Laboratory of Medical Molecular Virology, Department of Infectious Diseases, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Shuo Zhang
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, United States
| | - Lili Tian
- Beijing Research Institute for Tuberculosis Control, Beijing, China
| | - Wanliang Shi
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, United States
| | - David Sullivan
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, United States
| | - Bingdong Zhu
- Lanzhou Center for Tuberculosis Research and Institute of Pathogenic Biology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Wenhong Zhang
- Key Laboratory of Medical Molecular Virology, Department of Infectious Diseases, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Ying Zhang
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, United States
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Abstract
Urinary tract infections (UTIs) cause a huge burden of morbidity worldwide with recurrent UTIs becoming increasingly frequent owing to the emergence of antibiotic-resistant bacterial strains. Interactions between the innate and adaptive immune responses to pathogens colonizing the urinary tract have been the focus of much research. Inflammasomes are part of the innate immune defence and can respond rapidly to infectious insult. Assembly of the multiprotein inflammasome complex activates caspase-1, processes proinflammatory cytokines IL-1β and IL-18, and induces pyroptosis. These effector pathways, in turn, act at different levels to either prevent or resolve infection, or eliminate the infectious agent itself. In certain instances, inflammasome activation promotes tissue pathology; however, the precise functions of inflammasomes in UTIs remain unexplored. An improved understanding of inflammasomes could provide novel approaches for the design of diagnostics and therapeutics for complicated UTIs, enabling us to overcome the challenge of drug resistance.
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