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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: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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2
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DuPont HL. The potential for development of clinically relevant microbial resistance to rifaximin-α: a narrative review. Clin Microbiol Rev 2023; 36:e0003923. [PMID: 37971270 PMCID: PMC10732030 DOI: 10.1128/cmr.00039-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023] Open
Abstract
Rifaximin-α is a gut-targeted antibiotic indicated for numerous gastrointestinal and liver diseases. Its multifaceted mechanism of action goes beyond direct antimicrobial effects, including alterations in bacterial virulence, cytoprotective effects on host epithelial cells, improvement of impaired intestinal permeability, and reduction of proinflammatory cytokine expression via activation of the pregnane X receptor. Rifaximin-α is virtually non-absorbed, with low systemic drug levels contributing to its excellent safety profile. While there are high concentrations of drug in the colon, low water solubility leads to low colonic drug bioavailability, protecting the gut microbiome. Rifaximin-α appears to be more active in the bile-rich small bowel. Its important biologic effects are largely at sub-inhibitory concentration. Although in vitro testing of clinical isolates from rifaximin recipients has revealed rifaximin-resistant strains in some studies, the risk of emergent rifaximin-α resistance appears to be lower than for many other antibiotics. Rifaximin-α has been used for many years for traveler's diarrhea with no apparent increase in resistance levels in causative pathogens. Further, rifaximin-α retains its efficacy after long-term and recurrent usage in chronic gastrointestinal disorders. There are numerous reasons why the risk of microbial resistance to rifaximin-α may be lower than that for other agents, including low intestinal bioavailability in the aqueous colon, the mechanisms of action of rifaximin-α not requiring inhibitory concentrations of drug, and the low risk of cross transmission of rifaximin-α resistance between bacterial species. Reported emergence of vancomycin-resistant Enterococcus in liver-disease patients maintained on rifaximin needs to be actively studied. Further studies are required to assess the possible correlation between in vitro resistance and rifaximin-α efficacy.
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Affiliation(s)
- Herbert L. DuPont
- School of Public Health and McGovern Medical School, Baylor College of Medicine, Kelsey Research Foundation, University of Texas Health Science Center Houston, Houston, Texas, USA
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3
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Séraphin MN, Bellot J, Klann E, Ukhanova M, Saulsberry FG, Peloquin CA, Mai V. Gut microbiota composition and diversity before, during, and two months after rifamycin-based tuberculosis preventive therapy. Sci Rep 2023; 13:18933. [PMID: 37919333 PMCID: PMC10622450 DOI: 10.1038/s41598-023-44854-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 10/12/2023] [Indexed: 11/04/2023] Open
Abstract
Tuberculosis (TB) preventive therapy (TPT) is an effective strategy to eliminate TB in low-incidence settings. Shorter TPT regimens incorporating the antimicrobial class of rifamycins are designed to improve adherence and completion rates but carry the risk of modifications to the gut microbiota. We enrolled six subjects diagnosed with latent TB infection (LTBI) who accepted to initiate TPT. We also enrolled six healthy volunteers unexposed to the rifamycins. We profiled the gut microbiota using 16S rRNA amplicon sequencing (V1-V2 region) to document the immediate effect of rifamycin-based TPT on the gut microbiota composition and tracked recovery to baseline two months after TPT. Overall, TPT accounted for 17% of the variance in gut microbial community dissimilarity. This rifamycin-based TPT induced dysbiosis was characterized by a depletion of butyrate-producing taxa (Clostridium-XIVa and Roseburia) and expansion of potentially pathogenic taxa within the Firmicutes and Proteobacteria phyla. Recovery of the gut microbial composition was incomplete two months after TPT. Robust clinical studies are necessary to comprehensively catalogue TPT-induced gut microbiota dysbiosis to inform strategies to mitigate potential long-term sequelae of this important TB control intervention.
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Affiliation(s)
- Marie Nancy Séraphin
- Department of Medicine, Division of Infectious Diseases and Global Medicine, College of Medicine, University of Florida, Gainesville, FL, USA.
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA.
| | - Julia Bellot
- Department of Medicine, Division of Infectious Diseases and Global Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Emily Klann
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
- Department of Epidemiology, College of Public Health and Health Professions and College of Medicine, University of Florida, Gainesville, FL, USA
| | - Maria Ukhanova
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
- Department of Epidemiology, College of Public Health and Health Professions and College of Medicine, University of Florida, Gainesville, FL, USA
| | - Florence G Saulsberry
- Florida Department of Health in Alachua County, Disease Control Unit, Alachua County Health Department, Gainesville, FL, USA
| | - Charles A Peloquin
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
- Infectious Disease Pharmacokinetics Laboratory, College of Pharmacy, University of Florida, Gainesville, FL, USA
| | - Volker Mai
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
- Department of Epidemiology, College of Public Health and Health Professions and College of Medicine, University of Florida, Gainesville, FL, USA
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Noor H, David IG, Jinga ML, Popa DE, Buleandra M, Iorgulescu EE, Ciobanu AM. State of the Art on Developments of (Bio)Sensors and Analytical Methods for Rifamycin Antibiotics Determination. Sensors (Basel) 2023; 23:976. [PMID: 36679772 PMCID: PMC9863535 DOI: 10.3390/s23020976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/06/2023] [Accepted: 01/12/2023] [Indexed: 06/17/2023]
Abstract
This review summarizes the literature data reported from 2000 up to the present on the development of various electrochemical (voltammetric, amperometric, potentiometric and photoelectrochemical), optical (UV-Vis and IR) and luminescence (chemiluminescence and fluorescence) methods and the corresponding sensors for rifamycin antibiotics analysis. The discussion is focused mainly on the foremost compound of this class of macrocyclic drugs, namely rifampicin (RIF), which is a first-line antituberculosis agent derived from rifampicin SV (RSV). RIF and RSV also have excellent therapeutic action in the treatment of other bacterial infectious diseases. Due to the side-effects (e.g., prevalence of drug-resistant bacteria, hepatotoxicity) of long-term RIF intake, drug monitoring in patients is of real importance in establishing the optimum RIF dose, and therefore, reliable, rapid and simple methods of analysis are required. Based on the studies published on this topic in the last two decades, the sensing principles, some examples of sensors preparation procedures, as well as the performance characteristics (linear range, limits of detection and quantification) of analytical methods for RIF determination, are compared and correlated, critically emphasizing their benefits and limitations. Examples of spectrometric and electrochemical investigations of RIF interaction with biologically important molecules are also presented.
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Affiliation(s)
- Hassan Noor
- Department of Surgery, Faculty of Medicine, “Lucian Blaga” University Sibiu, Lucian Blaga Street 25, 550169 Sibiu, Romania
| | - Iulia Gabriela David
- Department of Analytical Chemistry and Physical Chemistry, Faculty of Chemistry, University of Bucharest, Panduri Av. 90-92, District 5, 050663 Bucharest, Romania
| | - Maria Lorena Jinga
- Department of Analytical Chemistry and Physical Chemistry, Faculty of Chemistry, University of Bucharest, Panduri Av. 90-92, District 5, 050663 Bucharest, Romania
| | - Dana Elena Popa
- Department of Analytical Chemistry and Physical Chemistry, Faculty of Chemistry, University of Bucharest, Panduri Av. 90-92, District 5, 050663 Bucharest, Romania
| | - Mihaela Buleandra
- Department of Analytical Chemistry and Physical Chemistry, Faculty of Chemistry, University of Bucharest, Panduri Av. 90-92, District 5, 050663 Bucharest, Romania
| | - Emilia Elena Iorgulescu
- Department of Analytical Chemistry and Physical Chemistry, Faculty of Chemistry, University of Bucharest, Panduri Av. 90-92, District 5, 050663 Bucharest, Romania
| | - Adela Magdalena Ciobanu
- Department of Psychiatry “Prof. Dr. Al. Obregia” Clinical Hospital of Psychiatry, Berceni Av. 10, District 4, 041914 Bucharest, Romania
- Discipline of Psychiatry, Neurosciences Department, Faculty of Medicine, “Carol Davila” University of Medicine and Pharmacy, Dionisie Lupu Street 37, 020021 Bucharest, Romania
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5
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Hurst-Hess KR, Saxena A, Rudra P, Yang Y, Ghosh P. Mycobacterium abscessus HelR interacts with RNA polymerase to confer intrinsic rifamycin resistance. Mol Cell 2022; 82:3166-3177.e5. [PMID: 35905736 PMCID: PMC9444957 DOI: 10.1016/j.molcel.2022.06.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 02/08/2022] [Accepted: 06/28/2022] [Indexed: 10/16/2022]
Abstract
Rifampicin (RIF), the frontline drug against M. tuberculosis, is completely ineffective against M. abscessus, partially due to the presence of an ADP-ribosyltransferase (Arr) that inactivates RIF. Using RNA-seq, we show that exposure of M. abscessus to sublethal doses of RIF and Rifabutin (RBT), a close analog of RIF, results in an ∼25-fold upregulation of Mab_helR in laboratory and clinical isolates. An isogenic deletion in Mab_helR results in RIF/RBT hypersensitivity, and overexpression of Mab_helR confers RIF tolerance in M. tuberculosis. We demonstrate an increased HelR-RNAP association in RIF-exposed bacteria and a MabHelR-mediated dissociation of RNAP from stalled initiation complexes in vitro. Finally, we show that the tip of the PCh-loop of Mab_helR, present in proximity to RIF, is critical for conferring RIF resistance but dispensable for dissociation of stalled RNAP complexes, suggesting that HelR-mediated RIF resistance requires a step in addition to displacement of RIF-stalled RNAP.
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Affiliation(s)
- Kelley R Hurst-Hess
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA
| | - Aavrati Saxena
- School of Public Health, University at Albany, Albany, NY 12208, USA
| | - Paulami Rudra
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA
| | - Yong Yang
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA
| | - Pallavi Ghosh
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA; School of Public Health, University at Albany, Albany, NY 12208, USA.
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Zloh M, Gupta M, Parish T, Brucoli F. Novel C-3-(N-alkyl-aryl)-aminomethyl rifamycin SV derivatives exhibit activity against rifampicin-resistant Mycobacterium tuberculosis RpoB S522L strain and display a different binding mode at the RNAP β-subunit site compared to rifampicin. Eur J Med Chem 2021; 225:113734. [PMID: 34418786 DOI: 10.1016/j.ejmech.2021.113734] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 07/26/2021] [Accepted: 07/28/2021] [Indexed: 11/16/2022]
Abstract
Antimicrobial resistance is a main concern in tuberculosis treatment and is often associated with the emergence of Mycobacterium tuberculosis strains resistant to rifampicin (RIF), which is one of the cornerstones of tuberculosis chemotherapy. In this study, aminoalkyl-aromatic ring tails were appended to the C3 position of rifamycin core to assess the role of C3 substitutions to the anti-mycobacterial activity of the rifamycin antibiotics. The typical hydrazone unit of RIF was replaced by an amino-alkyl linkage to connect the aromatic ring tails with the rifamycin naphthoquinone core. Eight novel C3-(N-alkyl-aryl)-aminoalkyl analogues of rifamycin SV were synthesised and screened in vitro against wild-type HR37Rv and "hypervirulent" HN-878 strains, and a panel of rifampicin-resistant M. tuberculosis clinical isolates carrying mutations at the 522, 531 and 455 positions of the rpoB gene (RpoBS522L, RpoBS531L and RpoBH455D strains). The analogues exhibited anti-tubercular activity against H37Rv and HN-878 at submicromolar or nanomolar concentrations, and against clinical H37Rv isolates bearing the S522L mutations at low micromolar concentration. Benzylamine moiety-including analogue 8 was as active as rifampicin against HN-878 with a MIC90 value of 0.02 μM, whereas 14 and 15, which included tryptamine and para-methyl-sulfonylbenzylamine C3-substituents, respectively, showed higher anti-tubercular activity (MIC90 = 3 μM) compared to rifampicin against the S522L mutated H37Rv strain. Detailed in silico analysis of different RNAP molecular systems predicted a distinct, possibly novel, binding mode for the new rifamycin analogues. These were found to occupy a different space in the binding pockets of both wild type and mutated RNAP proteins compared to that of rifampicin. Moreover, the molecular modelling experiments investigated the ability of the novel analogues aromatic tails to establish key interactions at the RNAP binding site. These interesting findings might pave the way for generating rifamycin analogues that can overcome anti-microbial resistance in M. tuberculosis.
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Affiliation(s)
- Mire Zloh
- Faculty of Pharmacy, University Business Academy, Novi Sad, 2100, Serbia; UCL School of Pharmacy, UCL, London, WC1N 1AX, UK
| | - Megha Gupta
- Infectious Disease Research Institute, 1616 Eastlake Ave E, Suite 400, Seattle, WA, 98102, USA
| | - Tanya Parish
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, 307 Westlake Avenue North, Suite 500, Seattle, USA
| | - Federico Brucoli
- Leicester School of Pharmacy, De Montfort University, Leicester, LE1 9BH, UK.
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Shi Y, Ye F, Song Y, Zhang X, Lu C, Shen Y. Rifamycin W Analogues from Amycolatopsis mediterranei S699 Δ rif- orf5 Strain. Biomolecules 2021; 11:920. [PMID: 34206314 PMCID: PMC8301457 DOI: 10.3390/biom11070920] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/15/2021] [Accepted: 06/18/2021] [Indexed: 11/16/2022] Open
Abstract
Rifamycin W, the most predominant intermediate in the biosynthesis of rifamycin, needs to undergo polyketide backbone rearrangement to produce rifamycin B via an oxidative cleavage of the C-12/C-29 double bond. However, the mechanism of this putative oxidative cleavage has not been characterized yet. Rif-Orf5 (a putative cytochrome P450 monooxygenase) was proposed to be involved in the cleavage of this olefinic moiety of rifamycin W. In this study, the mutant strain Amycolatopsis mediterranei S699 Δrif-orf5 was constructed by in-frame deleting the rif-orf5 gene to afford thirteen rifamycin W congeners (1-13) including seven new ones (1-7). Their structures were elucidated by extensive analysis of 1D and 2D NMR spectroscopic data and high-resolution ESI mass spectra. Presumably, compounds 1-4 were derivatized from rifamycin W via C-5/C-11 retro-Claisen cleavage, and compounds 1-3, 9 and 10 featured a hemiacetal. Compounds 5-7 and 11 showed oxygenations at various sites of the ansa chain. In addition, compounds 1-3 exhibited antibacterial activity against Staphylococcus aureus with minimal inhibitory concentration (MIC) values of 5, 40 and 0.5 µg/mL, respectively. Compounds 1 and 3 showed modest antiproliferative activity against HeLa and Caco-2 cells with half maximal inhibitory concentration (IC50) values of about 50 µM.
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Affiliation(s)
- Yanrong Shi
- Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China; (Y.S.); (F.Y.); (Y.S.); (X.Z.); (C.L.)
- Key Laboratory Experimental Teratology of the Ministry of Education, Department of Physiology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
| | - Feng Ye
- Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China; (Y.S.); (F.Y.); (Y.S.); (X.Z.); (C.L.)
| | - Yuliang Song
- Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China; (Y.S.); (F.Y.); (Y.S.); (X.Z.); (C.L.)
| | - Xiaochun Zhang
- Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China; (Y.S.); (F.Y.); (Y.S.); (X.Z.); (C.L.)
| | - Chunhua Lu
- Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China; (Y.S.); (F.Y.); (Y.S.); (X.Z.); (C.L.)
| | - Yuemao Shen
- Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China; (Y.S.); (F.Y.); (Y.S.); (X.Z.); (C.L.)
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Gao S, Wang C, Yu X, Teng T, Shang Y, Jia J, Dong L, Zhao L, Liu S, Chu N, Huang H. Xpert MTB/RIF Ultra enhanced tuberculous pleurisy diagnosis for patients with unexplained exudative pleural effusion who underwent a pleural biopsy via thoracoscopy: A prospective cohort study. Int J Infect Dis 2021; 106:370-375. [PMID: 33845198 DOI: 10.1016/j.ijid.2021.04.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 04/01/2021] [Accepted: 04/04/2021] [Indexed: 12/12/2022] Open
Abstract
INTRODUCTION To evaluate the performance of Xpert MTB/RIF Ultra (Xpert-Ultra) in testing pleural tissue and fluid collected by medical thoracoscopy among patients with unexplained exudative pleural effusion. METHODS Patients with an undiagnosed exudative pleural effusion were prospectively and consecutively recruited. Pleural tissue and fluid were collected by medical thoracoscopy and subjected to culture, Xpert MTB/RIF (Xpert) and Xpert-Ultra assays. Histopathological examination was also performed with the tissue and used as the major reference. RESULTS Sixty-one patients were enrolled, including: 27 tuberculosis (TB) pleurisy, 15 malignancy and 19 other chronic infection cases. The sensitivity, specificity, positive predictive value, and negative predictive value of Xpert-Ultra for TB diagnosis were 85.19% (23/27), 97.06% (33/34), 95.83% (23/24), and 89.19% (33/37), respectively. Xpert-Ultra testing with the biopsy tissue alone had an equivalent diagnostic capacity to that of pathological examination for the diagnosis of confirmed TB cases. By combining the pathological examination with Xpert-Ultra for biopsy, the percentage of confirmed TB cases greatly increased (i.e. 92.59% (25/27)). The "trace" positive outcome of Xpert-Ultra was highly supportive of TB diagnosis for both biopsy tissue and pleural fluid examinations. CONCLUSION With the specimens collected by medical thoracoscopy, the Xpert-Ultra assay presented high value in identifying TB among pleurisy patients who had difficulties in etiological diagnosis.
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Affiliation(s)
- Shan Gao
- National Clinical Laboratory on Tuberculosis, Beijing Key Laboratory for Drug Resistant Tuberculosis Research, Beijing, China; Department of Tuberculosis, Beijing Chest Hospital, Capital Medical University, Beijing Tuberculosis and Thoracic Tumor Institute, Beijing, China
| | - Chong Wang
- Department of Thoracic Surgery, Beijing Chest Hospital, Capital Medical University, Beijing Tuberculosis and Thoracic Tumor Institute, Beijing, China
| | - Xia Yu
- National Clinical Laboratory on Tuberculosis, Beijing Key Laboratory for Drug Resistant Tuberculosis Research, Beijing, China
| | - Tianlu Teng
- National Clinical Laboratory on Tuberculosis, Beijing Key Laboratory for Drug Resistant Tuberculosis Research, Beijing, China; Department of Tuberculosis, Beijing Chest Hospital, Capital Medical University, Beijing Tuberculosis and Thoracic Tumor Institute, Beijing, China
| | - Yuanyuan Shang
- National Clinical Laboratory on Tuberculosis, Beijing Key Laboratory for Drug Resistant Tuberculosis Research, Beijing, China; Department of Tuberculosis, Beijing Chest Hospital, Capital Medical University, Beijing Tuberculosis and Thoracic Tumor Institute, Beijing, China
| | - Junnan Jia
- National Clinical Laboratory on Tuberculosis, Beijing Key Laboratory for Drug Resistant Tuberculosis Research, Beijing, China
| | - Lingling Dong
- National Clinical Laboratory on Tuberculosis, Beijing Key Laboratory for Drug Resistant Tuberculosis Research, Beijing, China
| | - Liping Zhao
- National Clinical Laboratory on Tuberculosis, Beijing Key Laboratory for Drug Resistant Tuberculosis Research, Beijing, China
| | - Shuku Liu
- Department of Thoracic Surgery, Beijing Chest Hospital, Capital Medical University, Beijing Tuberculosis and Thoracic Tumor Institute, Beijing, China.
| | - Naihui Chu
- Department of Tuberculosis, Beijing Chest Hospital, Capital Medical University, Beijing Tuberculosis and Thoracic Tumor Institute, Beijing, China.
| | - Hairong Huang
- National Clinical Laboratory on Tuberculosis, Beijing Key Laboratory for Drug Resistant Tuberculosis Research, Beijing, China.
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Ye F, Shi Y, Zhao S, Li Z, Wang H, Lu C, Shen Y. 8-Deoxy-Rifamycin Derivatives from Amycolatopsis mediterranei S699 ΔrifT Strain. Biomolecules 2020; 10:biom10091265. [PMID: 32887371 PMCID: PMC7563148 DOI: 10.3390/biom10091265] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 08/27/2020] [Accepted: 08/31/2020] [Indexed: 02/03/2023] Open
Abstract
Proansamycin X, a hypothetical earliest macrocyclic precursor in the biosynthesis of rifamycin, had never been isolated and identified. According to bioinformatics analysis, it was proposed that RifT (a putative NADH-dependent dehydrogenase) may be a candidate target responsible for the dehydrogenation of proansamycin X. In this study, the mutant strain Amycolatopsis mediterranei S699 ΔrifT was constructed by deleting the rifT gene. From this strain, eleven 8-deoxy-rifamycin derivatives (1–11) and seven known analogues (12–18) were isolated. Their structures were elucidated by extensive analysis of 1D and 2D NMR spectroscopic data and high-resolution ESI mass spectra. Compound 1 is a novel amide N-glycoside of seco-rifamycin. Compounds 2 and 3 feature conserved 11,12-seco-rifamycin W skeleton. The diverse post-modifications in the polyketide chain led to the production of 4–11. Compounds 2, 3, 5, 6, 13 and 15 exhibited antibacterial activity against Staphylococcus aureus (MIC (minimal inhibitory concentration) values of 10, 20, 20, 20, 40 and 20 μg/mL, respectively). Compounds 14, 15, 16, 17 and 18 showed potent antiproliferative activity against KG1 cells with IC50 (half maximal inhibitory concentration) values of 14.91, 44.78, 2.16, 18.67 and 8.07 μM, respectively.
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Affiliation(s)
- Feng Ye
- Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, No. 44 West Wenhua Road, Jinan 250012, China; (F.Y.); (Y.S.); (S.Z.); (Z.L.); (C.L.)
| | - Yanrong Shi
- Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, No. 44 West Wenhua Road, Jinan 250012, China; (F.Y.); (Y.S.); (S.Z.); (Z.L.); (C.L.)
| | - Shengliang Zhao
- Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, No. 44 West Wenhua Road, Jinan 250012, China; (F.Y.); (Y.S.); (S.Z.); (Z.L.); (C.L.)
| | - Zhiying Li
- Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, No. 44 West Wenhua Road, Jinan 250012, China; (F.Y.); (Y.S.); (S.Z.); (Z.L.); (C.L.)
| | - Haoxin Wang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China;
| | - Chunhua Lu
- Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, No. 44 West Wenhua Road, Jinan 250012, China; (F.Y.); (Y.S.); (S.Z.); (Z.L.); (C.L.)
| | - Yuemao Shen
- Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, No. 44 West Wenhua Road, Jinan 250012, China; (F.Y.); (Y.S.); (S.Z.); (Z.L.); (C.L.)
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China;
- Correspondence: ; Tel.: +86-531-8838-2108
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10
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Yuan Y, Wang X, Xu X, Liu Y, Li C, Yang M, Yang Y, Ma Z. Evaluation of a Dual-Acting Antibacterial Agent, TNP-2092, on Gut Microbiota and Potential Application in the Treatment of Gastrointestinal and Liver Disorders. ACS Infect Dis 2020; 6:820-831. [PMID: 31849218 DOI: 10.1021/acsinfecdis.9b00374] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
TNP-2092 is a unique multitargeting drug conjugate with extremely low propensity for development of resistance. The in vitro activity of TNP-2092 against a panel of urease-producing bacteria was similar to that of rifaximin, a locally acting antibiotic approved for the treatment of hepatic encephalopathy, irritable bowel syndrome with diarrhea, and traveler's diarrhea. When given orally, TNP-2092 exhibited low absorption and the majority of compound was recovered in feces as parent. The impact of oral TNP-2092 on gut microbiota was investigated in rats. TNP-2092 was administered to rats by oral gavage for 7 days. Feces samples were collected and analyzed by 16S rRNA sequencing. Although the total amount of bacterial load appeared relatively unchanged before, during, and after treatment, significant changes in the relative abundance of certain gut bacteria at family and genus levels were observed. Some of the changes are known to be associated with improvement of symptoms associated with liver cirrhosis and hepatic encephalopathy. The observed effects of TNP-2092 on gut microbiota in rats were similar to those of rifaximin. In vivo, TNP-2092 demonstrated potent efficacy in a mouse Clostridium difficile infection model, superior to metronidazole and vancomycin, with no relapse observed after treatment. TNP-2092 is currently in clinical development for the treatment of symptoms associated with gastrointestinal and liver disorders.
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Affiliation(s)
- Ying Yuan
- TenNor Therapeutics Limited, 218 Xinghu Street, Suzhou Industrial Park, Suzhou 215123, China
| | - Xiaomei Wang
- TenNor Therapeutics Limited, 218 Xinghu Street, Suzhou Industrial Park, Suzhou 215123, China
| | - Xiangyi Xu
- TenNor Therapeutics Limited, 218 Xinghu Street, Suzhou Industrial Park, Suzhou 215123, China
| | - Yu Liu
- TenNor Therapeutics Limited, 218 Xinghu Street, Suzhou Industrial Park, Suzhou 215123, China
| | - Cancan Li
- WuXi AppTec (Shanghai) Co., Ltd., 288 Fute Zhong Road, Waigaoqiao, China (Shanghai) Pilot Free Trade Zone, Shanghai 200131, China
| | - Meng Yang
- WuXi AppTec (Shanghai) Co., Ltd., 288 Fute Zhong Road, Waigaoqiao, China (Shanghai) Pilot Free Trade Zone, Shanghai 200131, China
| | - Yiqing Yang
- BGI Genomics, BGI Park, No.21 Hongan 3rd Street, Yantian District, Shenzhen 518083, China
| | - Zhenkun Ma
- TenNor Therapeutics Limited, 218 Xinghu Street, Suzhou Industrial Park, Suzhou 215123, China
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Hanh BTB, Park JW, Kim TH, Kim JS, Yang CS, Jang K, Cui J, Oh DC, Jang J. Rifamycin O, An Alternative Anti- Mycobacterium abscessus Agent. Molecules 2020; 25:molecules25071597. [PMID: 32244387 PMCID: PMC7181020 DOI: 10.3390/molecules25071597] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 03/26/2020] [Accepted: 03/30/2020] [Indexed: 02/07/2023] Open
Abstract
Mycobacterium abscessus is the most difficult-to-treat nontuberculous mycobacteria because of its resistance to many antibiotics. In this study, we screened the Korea Chemical Bank library for a bioluminescent reporter assay to identify molecules capable of acting against M. abscessus. On application of the assay, rifamycin O showed excellent in vitro activity with a narrow range of the minimum inhibitory concentration required to inhibit the growth of 90% of the bacterium (MIC90 = 4.0-6.2 μM); its in vivo efficacy in the zebrafish (Danio rerio) infection model was comparable to that of rifabutin at 25 μM. Furthermore, rifamycin O did not show significant toxicity in cells and the zebrafish model. These results are the first in vivo indication that rifamycin O may be a drug candidate for treating M. abscessus infections.
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Affiliation(s)
- Bui Thi Bich Hanh
- Molecular Mechanisms of Antibiotics, Division of Life Science, Research Institute of Life Science, Gyeongsang National University, Jinju 52828, Korea; (B.T.B.H.); (T.H.K.)
- Division of Applied Life Science (BK21plus Program), Gyeongsang National University, Jinju 52828, Korea
| | - June-Woo Park
- Environmental Biology Research Group, Korea Institute of Toxicology, Jinju 52834, Korea;
- Human and Environmental Toxicology Program, Korea University of Science and Technology (UST), Daejeon 34113, Korea
| | - Tae Ho Kim
- Molecular Mechanisms of Antibiotics, Division of Life Science, Research Institute of Life Science, Gyeongsang National University, Jinju 52828, Korea; (B.T.B.H.); (T.H.K.)
- Division of Applied Life Science (BK21plus Program), Gyeongsang National University, Jinju 52828, Korea
| | - Jae-Sung Kim
- Department of Bionano Technology, Hanyang University, Seoul 04763, Korea; (J.-S.K.); (C.-S.Y.)
- Department of Molecular & Life Science, Hanyang University, Ansan 15588, Korea
| | - Chul-Su Yang
- Department of Bionano Technology, Hanyang University, Seoul 04763, Korea; (J.-S.K.); (C.-S.Y.)
- Department of Molecular & Life Science, Hanyang University, Ansan 15588, Korea
| | - Kiseok Jang
- Department of Pathology, Hanyang University College of Medicine, Seoul 04763, Korea;
| | - Jinsheng Cui
- Natural Products Research Institute, College of Pharmacy, Seoul National University, Seoul 08826, Korea; (J.C.); (D.-C.O.)
| | - Dong-Chan Oh
- Natural Products Research Institute, College of Pharmacy, Seoul National University, Seoul 08826, Korea; (J.C.); (D.-C.O.)
| | - Jichan Jang
- Molecular Mechanisms of Antibiotics, Division of Life Science, Research Institute of Life Science, Gyeongsang National University, Jinju 52828, Korea; (B.T.B.H.); (T.H.K.)
- Division of Applied Life Science (BK21plus Program), Gyeongsang National University, Jinju 52828, Korea
- Correspondence: ; Tel.: +82-(0)55-772-1368
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12
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Rifamycin (Aemcolo) for treatment of travelers' diarrhea. Med Lett Drugs Ther 2019; 61:39-40. [PMID: 30845098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
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13
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Pyta K, Janas A, Szukowska M, Pecyna P, Jaworska M, Gajecka M, Bartl F, Przybylski P. Synthesis, docking and antibacterial studies of more potent amine and hydrazone rifamycin congeners than rifampicin. Eur J Med Chem 2019; 167:96-104. [PMID: 30769243 DOI: 10.1016/j.ejmech.2019.02.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Revised: 01/18/2019] [Accepted: 02/03/2019] [Indexed: 12/24/2022]
Abstract
New rifamycin congeners (1-33) with incorporated amine and hydrazone substituents leading to lipophilic and/or basic nature and altered rigidity of modified C(3) arm were synthesized and structurally characterized in detail. NMR spectroscopic studies at different temperatures indicate two types of structures of rifamycin congeners that are realized in solution: zwitterionic and non-ionic forms in dependence of the basicity of modified C(3) arm. The presence of rifamycin congeners in these two possible forms has a significant impact on the physico-chemical parameters such as lipophilicity (clogP) and water solubility and different binding mode of the C(3) arm of antibiotic at RNAP binding pocket (molecular target) leading to different antibacterial potency. The highest antibacterial potency against S. aureus (including MRSA and MLSB strains) and S. epidermidis strains, even higher than reference rifampicin (Rif) and rifaximin (Rifx) antibiotics, was found for rifamycin congeners bearing at the C(3) arm relatively rigid and basic substituents (bipiperidine and guanidine groups). These modifications provide favorable docking mode and excellent water solubility resulting in high potency (MICs 0.0078 μg/mL what gives ∼ 8.5 nM), irrespective whether rifamycin congener is a tertiary amine (15) or hydrazone (29). In turn, for a higher antibacterial potency of rifamycin congeners against E. faecalis strain (MICs 0.5 μg/mL that is 0.6 μM) as compared to Rif and Rifx, the most crucial factors are: bulkiness and the lipophilic character of the end of the C(3) rebuilt arm.
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Affiliation(s)
- Krystian Pyta
- Faculty of Chemistry, A. Mickiewicz University, Umultowska 89b, 61-614, Poznan, Poland
| | - Anna Janas
- Faculty of Chemistry, A. Mickiewicz University, Umultowska 89b, 61-614, Poznan, Poland
| | - Monika Szukowska
- Faculty of Chemistry, A. Mickiewicz University, Umultowska 89b, 61-614, Poznan, Poland
| | - Paulina Pecyna
- Department of Genetics and Pharmaceutical Microbiology, University of Medical Sciences, Swiecickiego 4, 60-781, Poznan, Poland
| | - Marcelina Jaworska
- Department of Genetics and Pharmaceutical Microbiology, University of Medical Sciences, Swiecickiego 4, 60-781, Poznan, Poland
| | - Marzena Gajecka
- Department of Genetics and Pharmaceutical Microbiology, University of Medical Sciences, Swiecickiego 4, 60-781, Poznan, Poland; Institute of Human Genetics, Polish Academy of Sciences, Strzeszynska 32, 60-479, Poznan, Poland
| | - Franz Bartl
- Humboldt-Universität zu Berlin, Lebenswissenschaftliche Fakultät, Institut für Biologie, Biophysikalische Chemie, Invalidenstr. 42, 10099, Berlin, Germany
| | - Piotr Przybylski
- Faculty of Chemistry, A. Mickiewicz University, Umultowska 89b, 61-614, Poznan, Poland.
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Peek J, Lilic M, Montiel D, Milshteyn A, Woodworth I, Biggins JB, Ternei MA, Calle PY, Danziger M, Warrier T, Saito K, Braffman N, Fay A, Glickman MS, Darst SA, Campbell EA, Brady SF. Rifamycin congeners kanglemycins are active against rifampicin-resistant bacteria via a distinct mechanism. Nat Commun 2018; 9:4147. [PMID: 30297823 PMCID: PMC6175910 DOI: 10.1038/s41467-018-06587-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 08/29/2018] [Indexed: 11/25/2022] Open
Abstract
Rifamycin antibiotics (Rifs) target bacterial RNA polymerases (RNAPs) and are widely used to treat infections including tuberculosis. The utility of these compounds is threatened by the increasing incidence of resistance (RifR). As resistance mechanisms found in clinical settings may also occur in natural environments, here we postulated that bacteria could have evolved to produce rifamycin congeners active against clinically relevant resistance phenotypes. We survey soil metagenomes and identify a tailoring enzyme-rich family of gene clusters encoding biosynthesis of rifamycin congeners (kanglemycins, Kangs) with potent in vivo and in vitro activity against the most common clinically relevant RifR mutations. Our structural and mechanistic analyses reveal the basis for Kang inhibition of RifR RNAP. Unlike Rifs, Kangs function through a mechanism that includes interfering with 5'-initiating substrate binding. Our results suggest that examining soil microbiomes for new analogues of clinically used antibiotics may uncover metabolites capable of circumventing clinically important resistance mechanisms.
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Affiliation(s)
- James Peek
- Laboratory of Genetically Encoded Small Molecules, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
| | - Mirjana Lilic
- Laboratory of Molecular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
| | - Daniel Montiel
- Laboratory of Genetically Encoded Small Molecules, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
| | - Aleksandr Milshteyn
- Laboratory of Genetically Encoded Small Molecules, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
| | - Ian Woodworth
- Laboratory of Genetically Encoded Small Molecules, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
| | - John B Biggins
- Laboratory of Genetically Encoded Small Molecules, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
| | - Melinda A Ternei
- Laboratory of Genetically Encoded Small Molecules, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
| | - Paula Y Calle
- Laboratory of Genetically Encoded Small Molecules, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
| | - Michael Danziger
- Laboratory of Genetically Encoded Small Molecules, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
| | - Thulasi Warrier
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, 10065, USA
| | - Kohta Saito
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, 10065, USA
- Department of Medicine, Weill Cornell Medicine, New York, NY, 10065, USA
| | - Nathaniel Braffman
- Laboratory of Molecular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
| | - Allison Fay
- Immunology Program, Sloan-Kettering Institute, New York, NY, 10065, USA
| | | | - Seth A Darst
- Laboratory of Molecular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA
| | - Elizabeth A Campbell
- Laboratory of Molecular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA.
| | - Sean F Brady
- Laboratory of Genetically Encoded Small Molecules, The Rockefeller University, 1230 York Avenue, New York, NY, 10065, USA.
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15
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El-Demerdash AS, Aggour MG, El-Azzouny MM, Abou-Khadra SH. Molecular analysis of integron gene cassette arrays associated multi-drug resistant Enterobacteriaceae isolates from poultry. Cell Mol Biol (Noisy-le-grand) 2018; 64:149-156. [PMID: 29729709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 04/22/2018] [Accepted: 04/23/2018] [Indexed: 06/08/2023]
Abstract
The study investigated 110 Enterobacteriaceae isolates from broiler chickens isolated from Sharkia poultry farms and analyzed the isolates antimicrobial resistance and the presence of integrons as a potential basis for this resistance. Antibiotic susceptibilities against 12 different antibiotics were determined by the disk diffusion method. Prevalences and classes of integrons were then detected in multi-drug resistant (MDR) strains using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) followed by sequencing of the variable parts. Fifty-three isolates were MDR (resistant to three or more antimicrobial agents). High resistance was detected for rifamycin (82.7%), erythromycin (67.2%), and amoxicillin-clavulanic acid (63%). Classes 1 and 2 integrons were detected in 38 of 53 MDR Enterobacteriaceae isolates of which the most common were Salmonella species (n=19), followed by Escherichia coli (12), Klebsiella pneumoniae (3), Proteus species (3), and Citrobacter freundii (1). Three isolates only harbored class 1 integrons while the remaining 35 isolates carried class 2. All class 1 integron positive isolates exhibited the same gene cassettes arrangements: 1.) dfrA12-orfF-aadA27 (1.6 kbp); 2.) aadA23 (1.0 kbp); and 3.) dfrA15 (0.8 kbp). Moreover, four different gene cassettes were identified within class 2 integrons: 1.) dfrA1-sat2-aadA30 (2 kbp) in all isolates; 2.) sat2-aadA1 (1.7 kbp) in only one isolate; 3.) catB2 (0.9 kbp) in four isolates; and 4.) a new variant of sat2 (0.65 kbp) in three isolates. Efforts should be made to introduce surveillance programs for monitoring antimicrobial resistance that could potentially be transmitted from broiler chickens to human via integrons.
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Sarathy JP, Via LE, Weiner D, Blanc L, Boshoff H, Eugenin EA, Barry CE, Dartois VA. Extreme Drug Tolerance of Mycobacterium tuberculosis in Caseum. Antimicrob Agents Chemother 2018; 62:e02266-17. [PMID: 29203492 PMCID: PMC5786764 DOI: 10.1128/aac.02266-17] [Citation(s) in RCA: 132] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 11/29/2017] [Indexed: 11/26/2022] Open
Abstract
Tuberculosis (TB) recently became the leading infectious cause of death in adults, while attempts to shorten therapy have largely failed. Dormancy, persistence, and drug tolerance are among the factors driving the long therapy duration. Assays to measure in situ drug susceptibility of Mycobacterium tuberculosis bacteria in pulmonary lesions are needed if we are to discover new fast-acting regimens and address the global TB threat. Here we take a first step toward this goal and describe an ex vivo assay developed to measure the cidal activity of anti-TB drugs against M. tuberculosis bacilli present in cavity caseum obtained from rabbits with active TB. We show that caseum M. tuberculosis bacilli are largely nonreplicating, maintain viability over the course of the assay, and exhibit extreme tolerance to many first- and second-line TB drugs. Among the drugs tested, only the rifamycins fully sterilized caseum. A similar trend of phenotypic drug resistance was observed in the hypoxia- and starvation-induced nonreplicating models, but with notable qualitative and quantitative differences: (i) caseum M. tuberculosis exhibits higher drug tolerance than nonreplicating M. tuberculosis in the Wayne and Loebel models, and (ii) pyrazinamide is cidal in caseum but has no detectable activity in these classic nonreplicating assays. Thus, ex vivo caseum constitutes a unique tool to evaluate drug potency against slowly replicating or nonreplicating bacilli in their native caseous environment. Intracaseum cidal concentrations can now be related to the concentrations achieved in the necrotic foci of granulomas and cavities to establish correlations between clinical outcome and lesion-centered pharmacokinetics-pharmacodynamics (PK-PD) parameters.
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Affiliation(s)
- Jansy P Sarathy
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | - Laura E Via
- Tuberculosis Research Section, Laboratory of Clinical Infectious Diseases, NIAID, NIH, Bethesda, Maryland, USA
- Institute of Infectious Disease and Molecular Medicine, Department of Clinical Laboratory Sciences, University of Cape Town, Cape Town, South Africa
| | - Danielle Weiner
- Tuberculosis Research Section, Laboratory of Clinical Infectious Diseases, NIAID, NIH, Bethesda, Maryland, USA
| | - Landry Blanc
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | - Helena Boshoff
- Tuberculosis Research Section, Laboratory of Clinical Infectious Diseases, NIAID, NIH, Bethesda, Maryland, USA
| | - Eliseo A Eugenin
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey, USA
- Department of Microbiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | - Clifton E Barry
- Tuberculosis Research Section, Laboratory of Clinical Infectious Diseases, NIAID, NIH, Bethesda, Maryland, USA
- Institute of Infectious Disease and Molecular Medicine, Department of Clinical Laboratory Sciences, University of Cape Town, Cape Town, South Africa
| | - Véronique A Dartois
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey, USA
- Department of Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey, USA
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18
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Kaji K, Takaya H, Saikawa S, Furukawa M, Sato S, Kawaratani H, Kitade M, Moriya K, Namisaki T, Akahane T, Mitoro A, Yoshiji H. Rifaximin ameliorates hepatic encephalopathy and endotoxemia without affecting the gut microbiome diversity. World J Gastroenterol 2017; 23:8355-8366. [PMID: 29307995 PMCID: PMC5743506 DOI: 10.3748/wjg.v23.i47.8355] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 10/30/2017] [Accepted: 11/14/2017] [Indexed: 02/06/2023] Open
Abstract
AIM To determine the efficacy of rifaximin for hepatic encephalopathy (HE) with the linkage of gut microbiome in decompensated cirrhotic patients.
METHODS Twenty patients (12 men and 8 women; median age, 66.8 years; range, 46-81 years) with decompensated cirrhosis (Child-pugh score > 7) underwent cognitive neuropsychological testing, endotoxin analysis, and fecal microbiome assessment at baseline and after 4 wk of treatment with rifaximin 400 mg thrice a day. HE was determined by serum ammonia level and number connection test (NCT)-A. Changes in whole blood endotoxin activity (EA) was analyzed by endotoxin activity assay. Fecal microbiome was assessed by 16S ribosome RNA (rRNA) gene sequencing.
RESULTS Treatment with rifaximin for 4 wk improved hyperammonemia (from 90.6 ± 23.9 μg/dL to 73.1 ± 33.1 μg/dL; P < 0.05) and time required for NCT (from 68.2 ± 17.4 s to 54.9 ± 20.3 s; P < 0.05) in patients who had higher levels at baseline. Endotoxin activity was reduced (from 0.43 ± 0.03 to 0.32 ± 0.09; P < 0.05) in direct correlation with decrease in serum ammonia levels (r = 0.5886, P < 0.05). No statistically significant differences were observed in the diversity estimator (Shannon diversity index) and major components of the gut microbiome between the baseline and after treatment groups (3.948 ± 0.548 at baseline vs 3.980 ± 0.968 after treatment; P = 0.544), but the relative abundances of genus Veillonella and Streptococcus were lowered.
CONCLUSION Rifaximin significantly improved cognition and reduced endotoxin activity without significantly affecting the composition of the gut microbiome in patients with decompensated cirrhosis.
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Affiliation(s)
- Kosuke Kaji
- Third Department of Internal Medicine, Nara Medical University, Kashihara 634-8522, Japan
| | - Hiroaki Takaya
- Third Department of Internal Medicine, Nara Medical University, Kashihara 634-8522, Japan
| | - Soichiro Saikawa
- Third Department of Internal Medicine, Nara Medical University, Kashihara 634-8522, Japan
| | - Masanori Furukawa
- Third Department of Internal Medicine, Nara Medical University, Kashihara 634-8522, Japan
| | - Shinya Sato
- Third Department of Internal Medicine, Nara Medical University, Kashihara 634-8522, Japan
| | - Hideto Kawaratani
- Third Department of Internal Medicine, Nara Medical University, Kashihara 634-8522, Japan
| | - Mitsuteru Kitade
- Third Department of Internal Medicine, Nara Medical University, Kashihara 634-8522, Japan
| | - Kei Moriya
- Third Department of Internal Medicine, Nara Medical University, Kashihara 634-8522, Japan
| | - Tadashi Namisaki
- Third Department of Internal Medicine, Nara Medical University, Kashihara 634-8522, Japan
| | - Takemi Akahane
- Third Department of Internal Medicine, Nara Medical University, Kashihara 634-8522, Japan
| | - Akira Mitoro
- Third Department of Internal Medicine, Nara Medical University, Kashihara 634-8522, Japan
| | - Hitoshi Yoshiji
- Third Department of Internal Medicine, Nara Medical University, Kashihara 634-8522, Japan
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Abstract
Amyloid aggregates are associated with several debilitating diseases, and there are numerous efforts to develop small molecule treatments against these diseases. One challenge associated with these efforts is determining protein binding site information for potential therapeutics because amyloid-forming proteins rapidly form oligomers and aggregates, making traditional protein structural analysis techniques challenging. Using β-2-microglobulin (β2m) as a model amyloid-forming protein along with two recently identified small molecule amyloid inhibitors (i.e., rifamycin SV and doxycycline), we demonstrate that covalent labeling and mass spectrometry (MS) can be used to map small-molecule binding sites for a rapidly aggregating protein. Specifically, three different covalent labeling reagents, namely diethylpyrocarbonate, 2,3-butanedione, and the reagent pair EDC/GEE, are used together to pinpoint the binding sites of rifamycin SV, doxycycline, and another molecule, suramin, which binds but does not inhibit Cu(II)-induced β2m amyloid formation. The labeling results reveal binding sites that are consistent with the known effects of these molecules on β2m amyloid formation and are in general agreement with molecular docking results. We expect that this combined covalent labeling approach will be applicable to other protein/small molecule systems that are difficult to study by traditional means.
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Affiliation(s)
- Tianying Liu
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Tyler M. Marcinko
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Patrick A. Kiefer
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Richard W. Vachet
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
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20
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Ponziani FR, Zocco MA, D’Aversa F, Pompili M, Gasbarrini A. Eubiotic properties of rifaximin: Disruption of the traditional concepts in gut microbiota modulation. World J Gastroenterol 2017; 23:4491-4499. [PMID: 28740337 PMCID: PMC5504364 DOI: 10.3748/wjg.v23.i25.4491] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Revised: 04/14/2017] [Accepted: 05/19/2017] [Indexed: 02/06/2023] Open
Abstract
Antibiotics are usually prescribed to cure infections but they also have significant modulatory effects on the gut microbiota. Several alterations of the intestinal bacterial community have been reported during antibiotic treatment, including the reduction of beneficial bacteria as well as of microbial alpha-diversity. Although after the discontinuation of antibiotic therapies it has been observed a trend towards the restoration of the original condition, the new steady state is different from the previous one, as if antibiotics induced some kind of irreversible perturbation of the gut microbial community. The poorly absorbed antibiotic rifaximin seem to be different from the other antibiotics, because it exerts non-traditional effects additional to the bactericidal/bacteriostatic activity on the gut microbiota. Rifaximin is able to reduce bacterial virulence and translocation, has anti-inflammatory properties and has been demonstrated to positively modulate the gut microbial composition. Animal models, culture studies and metagenomic analyses have demonstrated an increase in Bifidobacterium, Faecalibacterium prausnitzii and Lactobacillus abundance after rifaximin treatment, probably consequent to the induction of bacterial resistance, with no major change in the overall gut microbiota composition. Antibiotics are therefore modulators of the symbiotic relationship between the host and the gut microbiota. Specific antibiotics, such as rifaximin, can also induce eubiotic changes in the intestinal ecosystem; this additional property may represent a therapeutic advantage in specific clinical settings.
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Novoa-Farias O, Frati-Munari AC, Peredo MA, Flores-Juárez S, Novoa-García O, Galicia-Tapia J, Romero-Carpio CE. Susceptibility to rifaximin and other antimicrobials of bacteria isolated in patients with acute gastrointestinal infections in Southeast Mexico. Rev Gastroenterol Mex 2017; 82:226-233. [PMID: 28298258 DOI: 10.1016/j.rgmx.2016.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 10/14/2016] [Accepted: 10/25/2016] [Indexed: 06/06/2023]
Abstract
INTRODUCTION Enteropathogenic bacteria isolated in Mexico City have shown a high rate of resistance to different antibiotics, with the exception of rifaximin (RIF). RIF is a nonabsorbable antibiotic that reaches high fecal concentrations (≈ 8,000μg/g). Susceptibility to antimicrobials can vary in different geographic regions. AIM To study the susceptibility to rifaximin and other antimicrobials of enteropathogenic bacteria isolated in patients with acute diarrhea in the southeastern region of Mexico. MATERIAL AND METHODS A total of 614 strains of bacteria isolated from patients with acute diarrhea from 4 cities in Southeast Mexico were analyzed. An antibiogram with the following antibiotics was created: ampicillin (AMP), trimethoprim/sulfamethoxazole (T-S), neomycin (NEO), furazolidone (FUR), ciprofloxacin (CIP), chloramphenicol (CHL), and fosfomycin (FOS), assessed through the agar diffusion method at the standard concentrations recommended by the Clinical and Laboratory Standards Institute (CLSI) and the American Society for Microbiology (ASM), and RIF, assessed through microdilution at 4 concentrations. RESULTS The bacteria were Escherichia coli (55%), as the majority, in all its pathogenic variants, Shigella (16.8%), Salmonella (15.3%), Aeromonas (7.8%), and less than 5% Campylobacter, Yersinia, Vibrio, and Plesiomonas. The accumulated overall susceptibility to RIF was 69.1, 90.8, 98.9, and 100% at concentrations of 100, 200, 400, and 800μg/ml, respectively. Overall susceptibility to other antibiotics was FOS 82.8%, CHL 76.8%, CIP 73.9%, FUR 64%, T-S 58.7%, NEO 55.8%, and AMP 23.8%. Susceptibility to RIF at 400 and 800μg was significantly greater than with the other antimicrobials (P<.001). CONCLUSIONS The data of the present study were similar to those of a previous study carried out in Mexico City: susceptibility to RIF in > 98% of the bacterial strains and a high frequency of resistance to several common antimicrobials.
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Affiliation(s)
- O Novoa-Farias
- División de Microbiología Clínica, Unidad de Diagnóstico Microbiológico UDMSC, Ciudad de México, México
| | - A C Frati-Munari
- Departamento de Medicina Interna, Hospital Médica Sur, Ciudad de México, México.
| | - M A Peredo
- Alliance for the prudent use of antibiotics (APUA), Chapter México, Ciudad de México, México
| | - S Flores-Juárez
- Alliance for the prudent use of antibiotics (APUA), Chapter México, Ciudad de México, México
| | - O Novoa-García
- División de Microbiología Clínica, Unidad de Diagnóstico Microbiológico UDMSC, Ciudad de México, México
| | - J Galicia-Tapia
- División de Microbiología Clínica, Unidad de Diagnóstico Microbiológico UDMSC, Ciudad de México, México
| | - C E Romero-Carpio
- División de Microbiología Clínica, Unidad de Diagnóstico Microbiológico UDMSC, Ciudad de México, México
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Jatsenko T, Sidorenko J, Saumaa S, Kivisaar M. DNA Polymerases ImuC and DinB Are Involved in DNA Alkylation Damage Tolerance in Pseudomonas aeruginosa and Pseudomonas putida. PLoS One 2017; 12:e0170719. [PMID: 28118378 PMCID: PMC5261740 DOI: 10.1371/journal.pone.0170719] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 01/09/2017] [Indexed: 12/12/2022] Open
Abstract
Translesion DNA synthesis (TLS), facilitated by low-fidelity polymerases, is an important DNA damage tolerance mechanism. Here, we investigated the role and biological function of TLS polymerase ImuC (former DnaE2), generally present in bacteria lacking DNA polymerase V, and TLS polymerase DinB in response to DNA alkylation damage in Pseudomonas aeruginosa and P. putida. We found that TLS DNA polymerases ImuC and DinB ensured a protective role against N- and O-methylation induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in both P. aeruginosa and P. putida. DinB also appeared to be important for the survival of P. aeruginosa and rapidly growing P. putida cells in the presence of methyl methanesulfonate (MMS). The role of ImuC in protection against MMS-induced damage was uncovered under DinB-deficient conditions. Apart from this, both ImuC and DinB were critical for the survival of bacteria with impaired base excision repair (BER) functions upon alkylation damage, lacking DNA glycosylases AlkA and/or Tag. Here, the increased sensitivity of imuCdinB double deficient strains in comparison to single mutants suggested that the specificity of alkylated DNA lesion bypass of DinB and ImuC might also be different. Moreover, our results demonstrated that mutagenesis induced by MMS in pseudomonads was largely ImuC-dependent. Unexpectedly, we discovered that the growth temperature of bacteria affected the efficiency of DinB and ImuC in ensuring cell survival upon alkylation damage. Taken together, the results of our study disclosed the involvement of ImuC in DNA alkylation damage tolerance, especially at low temperatures, and its possible contribution to the adaptation of pseudomonads upon DNA alkylation damage via increased mutagenesis.
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Affiliation(s)
- Tatjana Jatsenko
- Department of Genetics, Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
- * E-mail: (MK); (TJ)
| | - Julia Sidorenko
- Department of Genetics, Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Signe Saumaa
- Department of Genetics, Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Maia Kivisaar
- Department of Genetics, Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
- * E-mail: (MK); (TJ)
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Ciobanu L, Tantau M, Valean S, Parau A, Bedecean I, Mîrleneanu R, Berce C, Catoi C, Taulescu M. Rifaximin modulates 5-fluorouracil-induced gastrointestinal mucositis in rats. Eur Rev Med Pharmacol Sci 2016; 20:4993-5001. [PMID: 27981532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
OBJECTIVE This study assessed the protective potential of rifaximin in 5-fluorouracil (5-FU) induced intestinal mucositis in the Wistar rats'. MATERIALS AND METHODS Twenty-nine Wistar rats were divided into 4 interventional groups of 6 animals (A, B, C and F) and one control group (M) of 5 animals. Groups A, B and C received for three days consecutively rifaximin orally: 50 mg/kg (group A), 100 mg/kg (group B) and 200 mg/kg (group C). In the fourth day, 500 mg/kg of 5-FU was administered intraperitoneally to the groups A, B, C and F. A semi-quantitative histological assessment for duodenum, jejunum and colon were obtained by rating 11 histological characteristics of mucositis from 0 (normal) to 3 (severe). Semi-quantitative grades were a measure for TLR4 immunopositive cells. Statistical comparisons used - U Test, with a Bonferroni correction for alpha (p ≤ 0.016). RESULTS In the group F the most affected areas were the jejunum (median histological score 25) and the duodenum (median histological score 22). The assessment of duodenum histological lesions depicted significant difference between F and B groups (U = 1.5, p = 0.007) and between F and C groups (U = 0, p = 0.003). Graded microscopic degenerative lesions on jejunum were significantly different between F and C groups (U = 0, p = 0.004). Graded TLR4 immunopositive cells in the jejunum surface epithelium was significantly different between groups F and C (U = 2.5, p = 0.006). In the colonic mucosa, significantly differences were noted on microscopic degenerative lesions between F and A groups (U = 0, p = 0.004) and between F and C groups (U = 0, p = 0.004). CONCLUSIONS Pretreatment with 200 mg/kg of rifaximin for 3 consecutive days proved efficient in preventing intestinal mucosal degenerative lesions induced by 5-FU.
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Affiliation(s)
- L Ciobanu
- University of Medicine and Pharmacy Iuliu Hatieganu, Cluj-Napoca, Romania.
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Pandrea I, Xu C, Stock JL, Frank DN, Ma D, Policicchio BB, He T, Kristoff J, Cornell E, Haret-Richter GS, Trichel A, Ribeiro RM, Tracy R, Wilson C, Landay AL, Apetrei C. Antibiotic and Antiinflammatory Therapy Transiently Reduces Inflammation and Hypercoagulation in Acutely SIV-Infected Pigtailed Macaques. PLoS Pathog 2016; 12:e1005384. [PMID: 26764484 PMCID: PMC4713071 DOI: 10.1371/journal.ppat.1005384] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Accepted: 12/16/2015] [Indexed: 01/08/2023] Open
Abstract
Increased chronic immune activation and inflammation are hallmarks of HIV/SIV infection and are highly correlated with progression to AIDS and development of non-AIDS comorbidities, such as hypercoagulability and cardiovascular disease. Intestinal dysfunction resulting in microbial translocation has been proposed as a lead cause of systemic immune activation and hypercoagulability in HIV/SIV infection. Our goal was to assess the biological and clinical impact of a therapeutic strategy designed to reduce microbial translocation through reduction of the microbial content of the intestine (Rifaximin-RFX) and of gut inflammation (Sulfasalazine-SFZ). RFX is an intraluminal antibiotic that was successfully used in patients with hepatic encephalopathy. SFZ is an antiinflammatory drug successfully used in patients with mild to moderate inflammatory bowel disease. Both these clinical conditions are associated with increased microbial translocation, similar to HIV-infected patients. Treatment was administered for 90 days to five acutely SIV-infected pigtailed macaques (PTMs) starting at the time of infection; seven untreated SIVsab-infected PTMs were used as controls. RFX+SFZ were also administered for 90 days to three chronically SIVsab-infected PTMs. RFX+SFZ administration during acute SIVsab infection of PTMs resulted in: significantly lower microbial translocation, lower systemic immune activation, lower viral replication, better preservation of mucosal CD4+ T cells and significantly lower levels of hypercoagulation biomarkers. This effect was clear during the first 40 days of treatment and was lost during the last stages of treatment. Administration of RFX+SFZ to chronically SIVsab–infected PTMs had no discernible effect on infection. Our data thus indicate that early RFX+SFZ administration transiently improves the natural history of acute and postacute SIV infection, but has no effect during chronic infection. We report that administration of the intraluminal antibiotic Rifaximin and the gut-focused anti-inflammatory drug Sulfasalazine to acutely SIV-infected pigtailed macaques is associated with a transient disruption of the vicious circle of inflammation-microbial translocation-immune activation which is pathognomonic to pathogenic HIV/SIV infection and drives HIV disease progression and non-AIDS comorbidities in HIV-infected patients. This therapeutic approach resulted in transient lower microbial translocation, lower systemic immune activation, lower viral replication, better preservation of mucosal CD4+ T cells and lower levels of hypercoagulation biomarkers throughout acute SIV infection. Our results thus support the use of therapeutic approaches to reduce microbial translocation, improve the clinical outcome of HIV-infected patients receiving antiretroviral therapy and prevent non-AIDS comorbidities. Our results also reinforce the importance of early therapeutic management of HIV infection.
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Affiliation(s)
- Ivona Pandrea
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Pathology, School of Medicine, University of Pittsburgh, Pittsburgh, Penssylvania, United States of America
- * E-mail:
| | - Cuiling Xu
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Jennifer L. Stock
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Daniel N. Frank
- Department of Medicine, University of Colorado, Aurora, Colorado, United States of America
| | - Dongzhu Ma
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Microbiology and Molecular Genetics, School of Medicine, University of Pittsburgh, Pittsburgh, Penssylvania, United States of America
| | - Benjamin B. Policicchio
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Tianyu He
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Jan Kristoff
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Elaine Cornell
- Department of Pathology and Laboratory Medicine, University of Vermont, Burlington, Vermont, United States of America
| | - George S. Haret-Richter
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Anita Trichel
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Division of Laboratory Animal Resources, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Ruy M. Ribeiro
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Russell Tracy
- Department of Pathology and Laboratory Medicine, University of Vermont, Burlington, Vermont, United States of America
| | - Cara Wilson
- Department of Medicine, University of Colorado, Aurora, Colorado, United States of America
| | - Alan L. Landay
- Department of Immunology and Microbiology, Rush University Medical Center, Chicago, Illinois, United States of America
| | - Cristian Apetrei
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Microbiology and Molecular Genetics, School of Medicine, University of Pittsburgh, Pittsburgh, Penssylvania, United States of America
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Manzhaliy EG, Virchenko OV, Falaleyeva TM, Kuryk OG. [MОRPHOLOGICAL HEPATIC CHANGES IN RATS WHILE CCL(4) —ІNDUCED CIRRHOSIS AND HEPATIC ENCEPHALOPATHY ON BACKGROUND OF TREATMENT]. Klin Khir 2016:66-70. [PMID: 30265490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Impact of choline alphoscerate on morphological hepatic indices in rats with hepatic cirrhosis and hepatic encephalopathy, caused by injection of 15% solution of CCl(4) during 4 weeks, in comparison to standard scheme of treatment, was studied. Reduction of the hepatic histological changes severity, of the injured hepatocytes volume, of stromal—parenchymal ratio and enhancement of nucleo—cytoplasmic ratio in rats with hepatic cirrhosis under the choline alphoscerate impact were noted. The fibrosis and histological activity index in accordance to Knodell's scale witnessed a reduction of severity of hepatic affection in rats, which were treated, using choline alphoscerate.
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Colquhoun JM, Wozniak RAF, Dunman PM. Clinically Relevant Growth Conditions Alter Acinetobacter baumannii Antibiotic Susceptibility and Promote Identification of Novel Antibacterial Agents. PLoS One 2015; 10:e0143033. [PMID: 26558753 PMCID: PMC4641712 DOI: 10.1371/journal.pone.0143033] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 10/29/2015] [Indexed: 12/13/2022] Open
Abstract
Biological processes that govern bacterial proliferation and survival in the host-environment(s) are likely to be vastly different from those that are required for viability in nutrient-rich laboratory media. Consequently, growth-based antimicrobial screens performed in conditions modeling aspects of bacterial disease states have the potential to identify new classes of antimicrobials that would be missed by screens performed in conventional laboratory media. Accordingly, we performed screens of the Selleck library of 853 FDA approved drugs for agents that exhibit antimicrobial activity toward the Gram-negative bacterial pathogen Acinetobacter baumannii during growth in human serum, lung surfactant, and/or the organism in the biofilm state and compared those results to that of conventional laboratory medium. Results revealed that a total of 90 compounds representing 73 antibiotics and 17 agents that were developed for alternative therapeutic indications displayed antimicrobial properties toward the test strain in at least one screening condition. Of the active library antibiotics only four agents, rifampin, rifaximin, ciprofloxacin and tetracycline, exhibited antimicrobial activity toward the organism during all screening conditions, whereas the remainder were inactive in ≥ 1 condition; 56 antibiotics were inactive during serum growth, 25 and 38 were inactive toward lung surfactant grown and biofilm-associated cells, respectively, suggesting that subsets of antibiotics may outperform others in differing infection settings. Moreover, 9 antibiotics that are predominantly used for the treatment Gram-positive pathogens and 10 non-antibiotics lacked detectable antimicrobial activity toward A. baumannii grown in conventional medium but were active during ≥ 1 alternative growth condition(s). Such agents may represent promising anti-Acinetobacter agents that would have likely been overlooked by antimicrobial whole cell screening assays performed in traditional laboratory screening media.
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Affiliation(s)
- Jennifer M. Colquhoun
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
| | - Rachel A. F. Wozniak
- Department of Ophthalmology, Flaum Eye Institute, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
| | - Paul M. Dunman
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, New York, United States of America
- * E-mail:
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Hodnik Ž, Tomašič T, Smodiš D, D'Amore C, Mašič LP, Fiorucci S, Kikelj D. Diethylstilbestrol-scaffold-based pregnane X receptor modulators. Eur J Med Chem 2015; 103:551-62. [PMID: 26408814 DOI: 10.1016/j.ejmech.2015.09.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 07/21/2015] [Accepted: 09/04/2015] [Indexed: 12/22/2022]
Abstract
Due to its function as a regulator of drug-metabolizing enzymes and transporters, pregnane X receptor (PXR) represents an important factor involved in drug metabolism. In this work, we describe the discovery of diethylstilbestrol-based PXR modulators, which were designed from marine sulfated steroids with PXR agonistic activity, solomonsterols A and B, and our recently reported bazedoxifene scaffold-derived PXR antagonists. The methylated diethylstilbestrol derivative 1 displayed potent PXR agonistic activity with an EC50 value of 10.5 μM, whereas compounds 3, 4 and 6 (IC50 for 6 = 27.4 μM) and diethylstilbestrol (2) itself (IC50 = 14.6 μM) exhibited PXR antagonistic effects in HepG2 cells. The PXR modulatory effects of the synthesized diethylstilbestrol derivatives were further confirmed by the induction of PXR-regulated CYP3A4 expression with compound 1, as well as by the inhibition of the rifaximin-promoted up-regulation of CYP3A4 expression with 2 and its derivative 6.
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Affiliation(s)
- Žiga Hodnik
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, 1000 Ljubljana, Slovenia
| | - Tihomir Tomašič
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, 1000 Ljubljana, Slovenia
| | - Domen Smodiš
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, 1000 Ljubljana, Slovenia
| | - Claudio D'Amore
- University of Perugia, Dipartimento di Medicina Clinica e Sperimentale, Nuova Facultàdi Medicina e Chirurgia, S. Andrea delle Fratte, 06132 Perugia, Italy
| | | | - Stefano Fiorucci
- University of Perugia, Dipartimento di Medicina Clinica e Sperimentale, Nuova Facultàdi Medicina e Chirurgia, S. Andrea delle Fratte, 06132 Perugia, Italy
| | - Danijel Kikelj
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, 1000 Ljubljana, Slovenia.
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Rockwood N, Abdullahi LH, Wilkinson RJ, Meintjes G. Risk Factors for Acquired Rifamycin and Isoniazid Resistance: A Systematic Review and Meta-Analysis. PLoS One 2015; 10:e0139017. [PMID: 26406228 PMCID: PMC4583446 DOI: 10.1371/journal.pone.0139017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 09/07/2015] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Studies looking at acquired drug resistance (ADR) are diverse with respect to geographical distribution, HIV co-infection rates, retreatment status and programmatic factors such as regimens administered and directly observed therapy. Our objective was to examine and consolidate evidence from clinical studies of the multifactorial aetiology of acquired rifamycin and/or isoniazid resistance within the scope of a single systematic review. This is important to inform policy and identify key areas for further studies. METHODS Case-control and cohort studies and randomised controlled trials that reported ADR as an outcome during antitubercular treatment regimens including a rifamycin and examined the association of at least 1 risk factor were included. Post hoc, we carried out random effects Mantel-Haenszel weighted meta-analyses of the impact of 2 key risk factors 1) HIV and 2) baseline drug resistance on the binary outcome of ADR. Heterogeneity was assessed used I2 statistic. As a secondary outcome, we calculated median cumulative incidence of ADR, weighted by the sample size of the studies. RESULTS Meta-analysis of 15 studies showed increased risk of ADR with baseline mono- or polyresistance (RR 4.85 95% CI 3.26 to 7.23, heterogeneity I2 58%, 95% CI 26 to 76%). Meta-analysis of 8 studies showed that HIV co-infection was associated with increased risk of ADR (RR 3.02, 95% CI 1.28 to 7.11); there was considerable heterogeneity amongst these studies (I2 81%, 95% CI 64 to 90%). Non-adherence, extrapulmonary/disseminated disease and advanced immunosuppression in HIV co-infection were other risk factors noted. The weighted median cumulative incidence of acquired multi drug resistance calculated in 24 studies (assuming whole cohort as denominator, regardless of follow up DST) was 0.1% (5th to 95th percentile 0.07 to 3.2%). CONCLUSION Baseline drug resistance and HIV co-infection were significant risk factors for ADR. There was a trend of positive association with non-adherence which is likely to contribute to the outcome of ADR. The multifactorial aetiology of ADR in a programmatic setting should be further evaluated via appropriately designed studies.
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Affiliation(s)
- Neesha Rockwood
- Department of Medicine, Imperial College, London W2 1PG, United Kingdom
- Clinical Infectious Diseases Research Initiative, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
- * E-mail:
| | - Leila H. Abdullahi
- Vaccines for Africa Initiative, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Robert J. Wilkinson
- Department of Medicine, Imperial College, London W2 1PG, United Kingdom
- Clinical Infectious Diseases Research Initiative, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
- Francis Crick Institute Mill Hill Laboratory, London, United Kingdom
- Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Graeme Meintjes
- Department of Medicine, Imperial College, London W2 1PG, United Kingdom
- Clinical Infectious Diseases Research Initiative, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
- Department of Medicine, University of Cape Town, Cape Town, South Africa
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Sanchez CJ, Shiels SM, Tennent DJ, Hardy SK, Murray CK, Wenke JC. Rifamycin Derivatives Are Effective Against Staphylococcal Biofilms In Vitro and Elutable From PMMA. Clin Orthop Relat Res 2015; 473:2874-84. [PMID: 25896136 PMCID: PMC4523531 DOI: 10.1007/s11999-015-4300-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Local antimicrobial delivery through polymethylmethacrylate beads (PMMA), commonly vancomycin, is used for the treatment of contaminated open fractures but has limited activity against Staphylococcus aureus biofilms, which occur commonly in such fractures. Rifamycins have activity against biofilms and are an effective treatment for osteoarticular infections involving staphylococcal biofilms, but there are limited studies evaluating the activity of rifamycin derivatives, other than rifampin, against biofilms of S. aureus and evaluating incorporation of these drugs into PMMA for treatment of contaminated open fractures. QUESTIONS/PURPOSES (1) Are rifamycin derivatives effective against established biofilms of clinical isolates of S. aureus? (2) Can PMMA be used as a carrier for rifamycin derivatives? METHODS Biofilms were developed and evaluated for susceptibility to a panel of antimicrobials in vitro using the minimum biofilm eradication concentration high-throughput model. Susceptibility was assessed by measuring bacterial recovery at 6 and 24 hours after antimicrobial treatment. Activity of rifamycin derivatives against intracellular bacteria was also evaluated using a gentamicin protection assay. Evaluation of PMMA as a carrier for rifampin and rifamycin derivatives was determined by assessing the curing time subsequent to loading of rifamycins and characterizing the release kinetics of rifamycins at daily intervals for 14 days from PMMA by performing bioassays. RESULTS Rifamycin derivatives between 1 and 8 µg/mL reduced bacteria within biofilms 5- to 9-logs and prevented bacterial recovery up to 24 hours post-treatment, indicating near to complete eradication of biofilms. Rifamycin derivatives at 32 µg/mL had activity against intracellular staphylococci, significantly reducing the number of internalized bacteria with limited effects on osteoblast viability. Rifampin was the only rifamycin observed to have a suitable release profile from PMMA, releasing 49% of the total antibiotic and maintaining a sustained released profile up to 14 days at a mean 28 ± 6 μg/mL. CONCLUSIONS Rifampin can be incorporated into PMMA and eluted at concentrations effective against biofilms and intracellular staphylococci. CLINICAL RELEVANCE Our in vitro findings suggest that local delivery of rifampin may be an effective strategy for the prevention and/or treatment of open fractures where S. aureus biofilms might develop. Clinical studies are needed to characterize what role this approach might have in the prevention and treatment of infections involving biofilms.
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Affiliation(s)
- Carlos J. Sanchez
- />Extremity Trauma & Regenerative Medicine Task Area, US Army Institute of Surgical Research, 3698 Chambers Pass, JBSA, Fort Sam Houston, TX 78234 USA
| | - Stefanie M. Shiels
- />Extremity Trauma & Regenerative Medicine Task Area, US Army Institute of Surgical Research, 3698 Chambers Pass, JBSA, Fort Sam Houston, TX 78234 USA
| | - David J. Tennent
- />Extremity Trauma & Regenerative Medicine Task Area, US Army Institute of Surgical Research, 3698 Chambers Pass, JBSA, Fort Sam Houston, TX 78234 USA
| | - Sharanda K. Hardy
- />Extremity Trauma & Regenerative Medicine Task Area, US Army Institute of Surgical Research, 3698 Chambers Pass, JBSA, Fort Sam Houston, TX 78234 USA
| | - Clinton K. Murray
- />Department of Medicine, Infectious Disease Service, San Antonio Military Medical Center, Fort Sam Houston, TX USA
| | - Joseph C. Wenke
- />Extremity Trauma & Regenerative Medicine Task Area, US Army Institute of Surgical Research, 3698 Chambers Pass, JBSA, Fort Sam Houston, TX 78234 USA
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30
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DuPont HL. Therapeutic Effects and Mechanisms of Action of Rifaximin in Gastrointestinal Diseases. Mayo Clin Proc 2015; 90:1116-24. [PMID: 26162610 DOI: 10.1016/j.mayocp.2015.04.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Revised: 04/27/2015] [Accepted: 04/29/2015] [Indexed: 02/06/2023]
Abstract
Emerging preclinical and clinic evidence described herein suggests that the mechanism of action of rifaximin is not restricted to direct antibacterial effects within the gastrointestinal tract. Data from this study were derived from general and clinical trial-specific PubMed searches of English-language articles on rifaximin available through December 3, 2014. Search terms included rifaximin alone and in combination (using the Boolean operation "AND") with travelers' diarrhea, hepatic encephalopathy, liver cirrhosis, irritable bowel syndrome, inflammatory bowel disease, and Crohn's disease. Rifaximin appears to reduce bacterial virulence and pathogenicity by inhibiting bacterial translocation across the gastrointestinal epithelial lining. Rifaximin was shown to decrease bacterial adherence to epithelial cells and subsequent internalization in a bacteria- and cell type-specific manner, without an alteration in bacterial counts, but with a down-regulation in epithelial proinflammatory cytokine expression. Rifaximin also appears to modulate gut-immune signaling. In animal models of inflammatory bowel disease, rifaximin produced therapeutic effects by activating the pregnane X receptor and thereby reducing levels of the proinflammatory transcription factor nuclear factor κB. Therefore, for a given disease state, rifaximin may act through several mechanisms of action to exert its therapeutic effects. Clinically, rifaximin 600 mg/d significantly reduced symptoms of travelers' diarrhea (eg, time to last unformed stool vs placebo [32.0 hours vs 65.5 hours, respectively; P=.001]). For the prevention of hepatic encephalopathy recurrence, data indicate that treating 4 patients with rifaximin 1100 mg/d for 6 months would prevent 1 episode of hepatic encephalopathy. For diarrhea-predominant irritable bowel syndrome, a significantly greater percentage (40.7%) of patients treated with rifaximin 1650 mg/d for 2 weeks experienced adequate global irritable bowel syndrome symptom relief vs placebo (31.7%; P<.001). Rifaximin may be best described as a gut microenvironment modulator with cytoprotection properties, and further studies are needed to determine whether these putative mechanisms of action play a direct role in clinical outcomes.
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Affiliation(s)
- Herbert L DuPont
- Center for Infectious Diseases, The University of Texas School of Public Health, Baylor College of Medicine, Baylor St. Luke's Medical Center, Kelsey Research Foundation, Houston, TX.
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Wan YC, Li T, Han YD, Zhang HY, Lin H, Zhang B. EFFECT OF PREGNANE XENOBIOTIC RECEPTOR ACTIVATION ON INFLAMMATORY BOWEL DISEASE TREATED WITH RIFAXIMIN. J BIOL REG HOMEOS AG 2015; 29:401-410. [PMID: 26122229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The causes and pathogenesis of Inflammatory Bowel Disease (IBD) are still not clearly understood. This study aims to prove the important role of rifaximin played in inflammatory reaction caused by abnormity of the intestinal mucosal immune system. Intestinal microflora can greatly promote and maintain the inflammatory reaction of IBD, therefore, antibiotics can be used to treat IBD. Rifaximin is a medicine usually used for local intestinal infection. Many clinical and basic studies have shown that both a single application of rifaximin and the joint application with other medicines could achieve a good efficacy. This paper studied the activation of Pregnane Xenobiotic Receptor (PXR) in treating IBD with rifaximin and analyzed its efficacy in IBD when PXR was involved in the transport of medicine and metabolism. The results prove that rifaximin can not only serve as an anti-microbial drug, but can activate PXR and actually weaken the reaction of IBD. Thus it is safe to say that rifaximin has great potential in treating IBD.
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Affiliation(s)
- Y C Wan
- Department of Endocrinology, China-Japan Union Hospital, Jilin University, Jilin University, Changchun, China
| | - T Li
- Department of Anesthesiology, China-Japan Union Hospital, Jilin University, Jilin University, Changchun, China
| | - Y-D Han
- Department of Anesthesiology, China-Japan Union Hospital, Jilin University, Jilin University, Changchun, China
| | - H-Y Zhang
- Microscopic Examination Department, China-Japan Union Hospital, Jilin University, Changchun, China
| | - H Lin
- Department of Internal Medicine, Outpatient Department of Air Force Aviation University, Jilin University, Changchun, China
| | - B Zhang
- Microscopic Examination Department, China-Japan Union Hospital, Jilin University, Changchun, China
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Kaur P, Rampal A, Singh Bedi PM, Bedi N. Ternary Inclusion Complexes of Rifaximin with β-Cyclodextrin and Sodium Deoxycholate for Solubility Enhancement. Curr Drug Discov Technol 2015; 12:179-189. [PMID: 26279215 DOI: 10.2174/1570163812666150817113230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 08/06/2015] [Accepted: 08/07/2015] [Indexed: 06/04/2023]
Abstract
Rifaximin is a rifamycin derivative, having extremely poor aqueous solubility. The objective of present study was to improve dissolution and solubility of drug using β-cyclodextrin inclusion complexes and also to evaluate the effect of presence of sodium deoxycholate on solubilization efficiency of β-cyclodextrin. The stochiometry of inclusion complexes of binary (drug-cyclodextrin) and ternary system (drug-cyclodextrin-sodium deoxycholate) were determined by phase solubility studies at 25 °C. The stability constants (K1:2) calculated from phase solubility analysis were 126 M(-1) and 267 M(-1) for binary and ternary systems respectively. The inclusion complexes were prepared by solvent evaporation method with the inclusion efficiency of 43% and 56.9% for binary and ternary systems followed by their characterization using fourier transform infrared spectroscopy, X-ray diffractometry, differential scanning calorimetry and in-vitro antibacterial activity. The solubility of drug was improved by 4.3 and 11.9 folds in binary and ternary inclusion complexes, respectively. Therefore, it can be concluded that the ternary inclusion complexation having better solubilization efficiency as compared to binary complexation.
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Affiliation(s)
| | | | | | - Neena Bedi
- Department of Pharmaceutical Sciences, Guru Nanak Dev University, Amritsar-143005, India.
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Ahluwalia V, Wade JB, Heuman DM, Hammeke TA, Sanyal AJ, Sterling RK, Stravitz RT, Luketic V, Siddiqui MS, Puri P, Fuchs M, Lennon MJ, Kraft KA, Gilles H, White MB, Noble NA, Bajaj JS. Enhancement of functional connectivity, working memory and inhibitory control on multi-modal brain MR imaging with Rifaximin in Cirrhosis: implications for the gut-liver-brain axis. Metab Brain Dis 2014; 29:1017-25. [PMID: 24590688 PMCID: PMC4155029 DOI: 10.1007/s11011-014-9507-6] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 02/12/2014] [Indexed: 12/11/2022]
Abstract
UNLABELLED Minimal hepatic encephalopathy (MHE) impairs daily functioning in cirrhosis, but its functional brain impact is not completely understood. To evaluate the effect of rifaximin, a gut-specific antibiotic, on the gut-liver-brain axis in MHE. HYPOTHESIS Rifaximin will reduce endotoxemia, enhance cognition, increase activation during working memory(N-back) and reduce activation needed for inhibitory control tasks. METHODS Cirrhotics with MHE underwent baseline endotoxin and cognitive testing, then underwent fMRI, diffusion tensor imaging and MR spectroscopy(MRS). On fMRI, two tasks; N-back (outcome: correct responses) and inhibitory control tests(outcomes: lure inhibition) were performed. All procedures were repeated after 8 weeks of rifaximin. RESULTS were compared before/after rifaximin. RESULTS 20 MHE patients (59.7 years) were included; sixteen completed pre/post-rifaximin scanning with 92% medication compliance. Pre-rifaximin patients had cognitive impairment. At trial-end, there was a significantly higher correct 2-back responses, ICT lure inhibitions and reduced endotoxemia(p = 0.002). This was accompanied by significantly higher activation from baseline in subcortical structures (thalamus, caudate, insula and hippocampus) and left parietal operculum (LPO) during N-back, decrease in fronto-parietal activation required for inhibiting lures, including LPO during ICT compared to baseline values. Connectivity studies in N-back showed significant shifts in linkages after therapy in fronto-parietal regions with a reduction in fractional anisotropy (FA) but not mean diffusivity (MD), and no change in MRS metabolites at the end of the trial. A significant improvement in cognition including working memory and inhibitory control, and fractional anisotropy without effect on MD or MRS, through modulation of fronto-parietal and subcortical activation and connectivity was seen after open-label rifaximin therapy in MHE.
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Affiliation(s)
- Vishwadeep Ahluwalia
- Radiology, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, VA
- Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, VA
| | - James B Wade
- Psychiatry, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, VA
| | - Douglas M Heuman
- Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, VA
| | | | - Arun J Sanyal
- Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, VA
| | - Richard K Sterling
- Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, VA
| | - R. Todd Stravitz
- Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, VA
| | - Velimir Luketic
- Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, VA
| | - Mohammad S Siddiqui
- Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, VA
| | - Puneet Puri
- Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, VA
| | - Michael Fuchs
- Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, VA
| | - Micheal J Lennon
- Radiology, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, VA
| | - Kenneth A Kraft
- Radiology, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, VA
| | - HoChong Gilles
- Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, VA
| | - Melanie B White
- Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, VA
| | - Nicole A Noble
- Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, VA
| | - Jasmohan S Bajaj
- Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and McGuire VA Medical Center, Richmond, VA
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Knudson SE, Awasthi D, Kumar K, Carreau A, Goullieux L, Lagrange S, Vermet H, Ojima I, Slayden RA. A trisubstituted benzimidazole cell division inhibitor with efficacy against Mycobacterium tuberculosis. PLoS One 2014; 9:e93953. [PMID: 24736743 PMCID: PMC3988029 DOI: 10.1371/journal.pone.0093953] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 03/10/2014] [Indexed: 12/05/2022] Open
Abstract
Trisubstituted benzimidazoles have demonstrated potency against Gram-positive and Gram-negative bacterial pathogens. Previously, a library of novel trisubstituted benzimidazoles was constructed for high throughput screening, and compounds were identified that exhibited potency against M. tuberculosis H37Rv and clinical isolates, and were not toxic to Vero cells. A new series of 2-cyclohexyl-5-acylamino-6-N, N-dimethylaminobenzimidazoles derivatives has been developed based on SAR studies. Screening identified compounds with potency against M. tuberculosis. A lead compound from this series, SB-P17G-A20, was discovered to have an MIC of 0.16 µg/mL and demonstrated efficacy in the TB murine acute model of infection based on the reduction of bacterial load in the lungs and spleen by 1.73±0.24 Log10 CFU and 2.68±Log10 CFU, respectively, when delivered at 50 mg/kg by intraperitoneal injection (IP) twice daily (bid). The activity of SB-P17G-A20 was determined to be concentration dependent and to have excellent stability in mouse and human plasma, and liver microsomes. Together, these studies demonstrate that SB-P17G-A20 has potency against M. tuberculosis clinical strains with varying susceptibility and efficacy in animal models of infection, and that trisubstituted benzimidazoles continue to be a platform for the development of novel inhibitors with efficacy.
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Affiliation(s)
- Susan E. Knudson
- Mycobacteria Research Laboratories, Department Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Divya Awasthi
- Department of Chemistry, Stony Brook University, Stony Brook, New York, United States of America
| | - Kunal Kumar
- Institute of Chemical Biology & Drug Discovery, Stony Brook University, Stony Brook, New York, United States of America
| | - Alexandra Carreau
- Infectious Disease Therapeutic Strategic Unit, Sanofi-Aventis R&D, Toulouse, France
| | - Laurent Goullieux
- Infectious Disease Therapeutic Strategic Unit, Sanofi-Aventis R&D, Toulouse, France
| | - Sophie Lagrange
- Infectious Disease Therapeutic Strategic Unit, Sanofi-Aventis R&D, Toulouse, France
| | - Hélèn Vermet
- Infectious Disease Therapeutic Strategic Unit, Sanofi-Aventis R&D, Montpellier, France
| | - Iwao Ojima
- Department of Chemistry, Stony Brook University, Stony Brook, New York, United States of America
- Institute of Chemical Biology & Drug Discovery, Stony Brook University, Stony Brook, New York, United States of America
| | - Richard A. Slayden
- Mycobacteria Research Laboratories, Department Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
- * E-mail:
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Evans SE, Goult BT, Fairall L, Jamieson AG, Ko Ferrigno P, Ford R, Schwabe JWR, Wagner SD. The ansamycin antibiotic, rifamycin SV, inhibits BCL6 transcriptional repression and forms a complex with the BCL6-BTB/POZ domain. PLoS One 2014; 9:e90889. [PMID: 24595451 PMCID: PMC3942486 DOI: 10.1371/journal.pone.0090889] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2013] [Accepted: 02/05/2014] [Indexed: 11/22/2022] Open
Abstract
BCL6 is a transcriptional repressor that is over-expressed due to chromosomal translocations, or other abnormalities, in ∼40% of diffuse large B-cell lymphoma. BCL6 interacts with co-repressor, SMRT, and this is essential for its role in lymphomas. Peptide or small molecule inhibitors, which prevent the association of SMRT with BCL6, inhibit transcriptional repression and cause apoptosis of lymphoma cells in vitro and in vivo. In order to discover compounds, which have the potential to be developed into BCL6 inhibitors, we screened a natural product library. The ansamycin antibiotic, rifamycin SV, inhibited BCL6 transcriptional repression and NMR spectroscopy confirmed a direct interaction between rifamycin SV and BCL6. To further determine the characteristics of compounds binding to BCL6-POZ we analyzed four other members of this family and showed that rifabutin, bound most strongly. An X-ray crystal structure of the rifabutin-BCL6 complex revealed that rifabutin occupies a partly non-polar pocket making interactions with tyrosine58, asparagine21 and arginine24 of the BCL6-POZ domain. Importantly these residues are also important for the interaction of BLC6 with SMRT. This work demonstrates a unique approach to developing a structure activity relationship for a compound that will form the basis of a therapeutically useful BCL6 inhibitor.
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Affiliation(s)
- Sian E. Evans
- Department of Biochemistry, University of Leicester, Leicester, United Kingdom
- Department of Cancer Studies and Molecular Medicine and MRC Toxicology Unit, University of Leicester, Leicester, United Kingdom
| | - Benjamin T. Goult
- Department of Biochemistry, University of Leicester, Leicester, United Kingdom
| | - Louise Fairall
- Department of Biochemistry, University of Leicester, Leicester, United Kingdom
| | - Andrew G. Jamieson
- Department of Chemistry, University of Leicester, Leicester, United Kingdom
| | - Paul Ko Ferrigno
- Section of Experimental Therapeutics, Leeds Institute of Molecular Medicine, University of Leeds, Leeds, United Kingdom
| | - Robert Ford
- Section of Experimental Therapeutics, Leeds Institute of Molecular Medicine, University of Leeds, Leeds, United Kingdom
| | - John W. R. Schwabe
- Department of Biochemistry, University of Leicester, Leicester, United Kingdom
| | - Simon D. Wagner
- Department of Cancer Studies and Molecular Medicine and MRC Toxicology Unit, University of Leicester, Leicester, United Kingdom
- * E-mail:
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Staudinger T, Redl B, Glasgow BJ. Antibacterial activity of rifamycins for M. smegmatis with comparison of oxidation and binding to tear lipocalin. Biochim Biophys Acta 2014; 1844:750-8. [PMID: 24530503 DOI: 10.1016/j.bbapap.2014.02.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Revised: 01/28/2014] [Accepted: 02/03/2014] [Indexed: 11/19/2022]
Abstract
A mutant of Mycobacterium smegmatis is a potential class I model substitute for Mycobacterium tuberculosis. Because not all of the rifamycins have been tested in this organism, we determined bactericidal profiles for the 6 major rifamycin derivatives. The profiles closely mirrored those established for M. tuberculosis. Rifalazil was confirmed to be the most potent rifamycin. Because the tuberculous granuloma presents a harshly oxidizing environment we explored the effects of oxidation on rifamycins. Mass spectrometry confirmed that three of the six major rifamycins showed autoxidation in the presence of trace metals. Oxidation could be monitored by distinctive changes including isosbestic points in the ultraviolet-visible spectrum. Oxidation of rifamycins abrogated anti-mycobacterial activity in M. smegmatis. Protection from autoxidation was conferred by binding susceptible rifamycins to tear lipocalin, a promiscuous lipophilic protein. Rifalazil was not susceptible to autoxidation but was insoluble in aqueous solution. Solubility was enhanced when complexed to tear lipocalin and was accompanied by a spectral red shift. The positive solvatochromism was consistent with robust molecular interaction and binding. Other rifamycins also formed a complex with lipocalin, albeit to a lesser extent. Protection from oxidation and enhancement of solubility with protein binding may have implications for delivery of select rifamycin derivatives.
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Affiliation(s)
- Tamara Staudinger
- Department of Ophthalmology, Jules Stein Eye Institute, University of California, Los Angeles, 100 Stein Plaza, Rm. B-279, Los Angeles, CA 90095, USA; Department of Pathology and Laboratory Medicine, Jules Stein Eye Institute, University of California, Los Angeles, 100 Stein Plaza, Rm. B-279, Los Angeles, CA 90095, USA; Division of Molecular Biology, Biocenter, Innsbruck Medical University, Innrain 80-82, A-6020 Innsbruck, Austria
| | - Bernhard Redl
- Division of Molecular Biology, Biocenter, Innsbruck Medical University, Innrain 80-82, A-6020 Innsbruck, Austria
| | - Ben J Glasgow
- Department of Ophthalmology, Jules Stein Eye Institute, University of California, Los Angeles, 100 Stein Plaza, Rm. B-279, Los Angeles, CA 90095, USA; Department of Pathology and Laboratory Medicine, Jules Stein Eye Institute, University of California, Los Angeles, 100 Stein Plaza, Rm. B-279, Los Angeles, CA 90095, USA.
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Sato K, Shimizu T, Dimova V, Tomioka H. Antimicrobial Activities of Cinnamyl Rifamycin Derivatives, T-9 and T-11, againstMycobacterium tuberculosisandMycobacterium aviumComplex (MAC) with Special Reference to the Activities against Intracellular MAC. Microbiol Immunol 2013; 50:621-3. [PMID: 16924146 DOI: 10.1111/j.1348-0421.2006.tb03836.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The mycobacterial activities of cinamyl rifamycin derivatives, T-9 and T-11, especially against extracellular and intracellular Mycobacterium avium complex residing within macrophages and type II pneumocytes were compared with those of other rifamycins. The activities of test rifamycins were found to be in the order rifalazil, rifabutin, T-9, T-11, and rifampicin.
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Affiliation(s)
- Katsumasa Sato
- Department of Microbiology and Immunology, Shimane University School of Medicine, Izumo, Shimane, Japan
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Schrodt C, McHugh EE, Gawinowicz MA, DuPont HL, Brown EL. Rifaximin-mediated changes to the epithelial cell proteome: 2-D gel analysis. PLoS One 2013; 8:e68550. [PMID: 23922656 PMCID: PMC3724845 DOI: 10.1371/journal.pone.0068550] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 05/30/2013] [Indexed: 12/11/2022] Open
Abstract
Rifaximin is a semi-synthetic rifamycin derivative that is used to treat different conditions including bacterial diarrhea and hepatic encephalopathy. Rifaximin is of particular interest because it is poorly adsorbed in the intestines and has minimal effect on colonic microflora. We previously demonstrated that rifaximin affected epithelial cell physiology by altering infectivity by enteric pathogens and baseline inflammation suggesting that rifaximin conferred cytoprotection against colonization and infection. Effects of rifaximin on epithelial cells were further examined by comparing the protein expression profile of cells pretreated with rifaximin, rifampin (control antibiotic), or media (untreated). Two-dimensional (2-D) gel electrophoresis identified 36 protein spots that were up- or down-regulated by over 1.7-fold in rifaximin treated cells compared to controls. 15 of these spots were down-regulated, including annexin A5, intestinal-type alkaline phosphatase, histone H4, and histone-binding protein RbbP4. 21 spots were up-regulated, including heat shock protein (HSP) 90α and fascin. Many of the identified proteins are associated with cell structure and cytoskeleton, transcription and translation, and cellular metabolism. These data suggested that in addition to its antimicrobial properties, rifaximin may alter host cell physiology that provides cytoprotective effects against bacterial pathogens.
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Affiliation(s)
- Caroline Schrodt
- Center for Infectious Diseases, the University of Texas School of Public Health, Houston, Texas, United States of America
| | - Erin E. McHugh
- Center for Infectious Diseases, the University of Texas School of Public Health, Houston, Texas, United States of America
| | - Mary Ann Gawinowicz
- Protein Core Facility, Columbia University College, New York, New York, United States of America
| | - Herbert L. DuPont
- Center for Infectious Diseases, the University of Texas School of Public Health, Houston, Texas, United States of America
- Internal Medicine Services, St. Luke’s Episcopal Hospital and Department of Medicine, Infectious Diseases Section, Baylor College of Medicine, Houston, Texas, United States of America
| | - Eric L. Brown
- Center for Infectious Diseases, the University of Texas School of Public Health, Houston, Texas, United States of America
- * E-mail:
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Kim MS, Morales W, Hani AA, Kim S, Kim G, Weitsman S, Chang C, Pimentel M. The effect of rifaximin on gut flora and Staphylococcus resistance. Dig Dis Sci 2013; 58:1676-82. [PMID: 23589147 DOI: 10.1007/s10620-013-2675-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 03/27/2013] [Indexed: 12/11/2022]
Abstract
AIM Rifaximin is a non-absorbed antibiotic relative of rifampicin. The location of effect and staphylococcal resistance are two recent potential concerns with rifaximin. In this study we evaluate the location of effect of rifaximin as well as the development of staphylococcal rifampicin resistance. METHODS Rats were divided into three groups. Group 1 gavaged for 10 days with PBS, group 2 gavaged with rifaximin for 10 days, and group 3 gavaged with rifaximin for 10 days and housed for 30 days. In each group, stool was collected daily for quantitative culture of Staphylococcus spp. and coliforms. After euthanasia luminal bacterial counts were determined at multiple gut locations by qPCR. Rifampicin susceptibility was tested on Staphylococcus pre and post rifaximin. RESULTS At baseline, rats had a median of 2.90 × 10(6) cfu/ml Staphylococcus spp. in stool. After 10 days of rifaximin, this dropped to 1.20 × 10(5) cfu/ml (P < 0.01). With coliform counts, rats had a median of 1.86 × 10(4) cfu/ml at baseline which dropped to 2.2 × 10(3) cfu/ml (P < 0.01) after rifaximin. After cessation of rifaximin, coliform counts recovered within 3 days. When examining the total bacterial counts by qPCR, rifaximin reduced small bowel bacterial levels, but not colon. This reduction was sustained for 30 days. No colonies of Staphylococcus became resistant and only one colony was intermediate. The mean inhibitory concentration for rifampicin was not different before and after rifaximin. CONCLUSION Staphylococcal spp. fail to demonstrate resistance to rifampicin after rifaximin. The transient reductions in stool coliform counts recover while rifaximin appears to produce durable reductions in duodenal bacteria.
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Affiliation(s)
- Mi-Sung Kim
- Division of Gastroenterology, Cheongju St. Mary's Hospital, Cheongju, Korea
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Bajaj JS, Heuman DM, Sanyal AJ, Hylemon PB, Sterling RK, Stravitz RT, Fuchs M, Ridlon JM, Daita K, Monteith P, Noble NA, White MB, Fisher A, Sikaroodi M, Rangwala H, Gillevet PM. Modulation of the metabiome by rifaximin in patients with cirrhosis and minimal hepatic encephalopathy. PLoS One 2013; 8:e60042. [PMID: 23565181 PMCID: PMC3615021 DOI: 10.1371/journal.pone.0060042] [Citation(s) in RCA: 302] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 02/19/2013] [Indexed: 12/12/2022] Open
Abstract
UNLABELLED Hepatic encephalopathy (HE) represents a dysfunctional gut-liver-brain axis in cirrhosis which can negatively impact outcomes. This altered gut-brain relationship has been treated using gut-selective antibiotics such as rifaximin, that improve cognitive function in HE, especially its subclinical form, minimal HE (MHE). However, the precise mechanism of the action of rifaximin in MHE is unclear. We hypothesized that modulation of gut microbiota and their end-products by rifaximin would affect the gut-brain axis and improve cognitive performance in cirrhosis. Aim To perform a systems biology analysis of the microbiome, metabolome and cognitive change after rifaximin in MHE. METHODS Twenty cirrhotics with MHE underwent cognitive testing, endotoxin analysis, urine/serum metabolomics (GC and LC-MS) and fecal microbiome assessment (multi-tagged pyrosequencing) at baseline and 8 weeks post-rifaximin 550 mg BID. Changes in cognition, endotoxin, serum/urine metabolites (and microbiome were analyzed using recommended systems biology techniques. Specifically, correlation networks between microbiota and metabolome were analyzed before and after rifaximin. RESULTS There was a significant improvement in cognition(six of seven tests improved, p<0.01) and endotoxemia (0.55 to 0.48 Eu/ml, p = 0.02) after rifaximin. There was a significant increase in serum saturated (myristic, caprylic, palmitic, palmitoleic, oleic and eicosanoic) and unsaturated (linoleic, linolenic, gamma-linolenic and arachnidonic) fatty acids post-rifaximin. No significant microbial change apart from a modest decrease in Veillonellaceae and increase in Eubacteriaceae was observed. Rifaximin resulted in a significant reduction in network connectivity and clustering on the correlation networks. The networks centered on Enterobacteriaceae, Porphyromonadaceae and Bacteroidaceae indicated a shift from pathogenic to beneficial metabolite linkages and better cognition while those centered on autochthonous taxa remained similar. CONCLUSIONS Rifaximin is associated with improved cognitive function and endotoxemia in MHE, which is accompanied by alteration of gut bacterial linkages with metabolites without significant change in microbial abundance. TRIAL REGISTRATION ClinicalTrials.gov NCT01069133.
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Affiliation(s)
- Jasmohan S Bajaj
- Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University and McGuire Veterans Affairs Medical Center, Richmond, Virginia, United States of America.
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Bielaszewska M, Idelevich EA, Zhang W, Bauwens A, Schaumburg F, Mellmann A, Peters G, Karch H. Effects of antibiotics on Shiga toxin 2 production and bacteriophage induction by epidemic Escherichia coli O104:H4 strain. Antimicrob Agents Chemother 2012; 56:3277-82. [PMID: 22391549 PMCID: PMC3370775 DOI: 10.1128/aac.06315-11] [Citation(s) in RCA: 145] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The role of antibiotics in treatment of enterohemorrhagic Escherichia coli (EHEC) infections is controversial because of concerns about triggering hemolytic-uremic syndrome (HUS) by increasing Shiga toxin (Stx) production. During the recent large EHEC O104:H4 outbreak, antibiotic therapy was indicated for some patients. We tested a diverse panel of antibiotics to which the outbreak strain is susceptible to interrogate the effects of subinhibitory antibiotic concentrations on induction of stx(2)-harboring bacteriophages, stx(2) transcription, and Stx2 production in this emerging pathogen. Ciprofloxacin significantly increased stx(2)-harboring phage induction and Stx2 production in outbreak isolates (P values of <0.001 to <0.05), while fosfomycin, gentamicin, and kanamycin insignificantly influenced them (P > 0.1) and chloramphenicol, meropenem, azithromycin, rifaximin, and tigecycline significantly decreased them (P ≤ 0.05). Ciprofloxacin and chloramphenicol significantly upregulated and downregulated stx(2) transcription, respectively (P < 0.01); the other antibiotics had insignificant effects (P > 0.1). Meropenem, azithromycin, and rifaximin, which were used for necessary therapeutic or prophylactic interventions during the EHEC O104:H4 outbreak, as well as tigecycline, neither induced stx(2)-harboring phages nor increased stx(2) transcription or Stx2 production in the outbreak strain. These antibiotics might represent therapeutic options for patients with EHEC O104:H4 infection if antibiotic treatment is inevitable. We await further analysis of the epidemic to determine if usage of these agents was associated with an altered risk of developing HUS.
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Affiliation(s)
- Martina Bielaszewska
- Institute of Hygiene and the National Consulting Laboratory for Hemolytic Uremic Syndrome, University of Münster, Münster, Germany
| | | | - Wenlan Zhang
- Institute of Hygiene and the National Consulting Laboratory for Hemolytic Uremic Syndrome, University of Münster, Münster, Germany
| | - Andreas Bauwens
- Institute of Hygiene and the National Consulting Laboratory for Hemolytic Uremic Syndrome, University of Münster, Münster, Germany
| | - Frieder Schaumburg
- Institute of Medical Microbiology, University of Münster, Münster, Germany
| | - Alexander Mellmann
- Institute of Hygiene and the National Consulting Laboratory for Hemolytic Uremic Syndrome, University of Münster, Münster, Germany
- Interdisciplinary Center of Clinical Research (IZKF), University of Münster, Münster, Germany
| | - Georg Peters
- Institute of Medical Microbiology, University of Münster, Münster, Germany
- Interdisciplinary Center of Clinical Research (IZKF), University of Münster, Münster, Germany
| | - Helge Karch
- Institute of Hygiene and the National Consulting Laboratory for Hemolytic Uremic Syndrome, University of Münster, Münster, Germany
- Interdisciplinary Center of Clinical Research (IZKF), University of Münster, Münster, Germany
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Sharma P, Butters CJ, Smith V, Elsby R, Surry D. Prediction of the in vivo OATP1B1-mediated drug-drug interaction potential of an investigational drug against a range of statins. Eur J Pharm Sci 2012; 47:244-55. [PMID: 22538052 DOI: 10.1016/j.ejps.2012.04.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 02/23/2012] [Accepted: 04/03/2012] [Indexed: 01/17/2023]
Abstract
To support drug development, the drug-drug interaction potential (DDI) of an investigational drug (AZX) was assessed against the probe estradiol 17β-glucuronide as well as against simvastatin acid, atorvastatin, pravastatin, pitavastatin, fluvastatin, rosuvastatin and estrone 3-sulfate. The inhibitory potentials of the OATP1B1 inhibitors rifamycin SV and gemfibrozil were assessed in parallel. Monolayer cellular uptake assays were used to determine inhibition of human OATP1B1. Apparent K(m) values for the OATP1B1-mediated transport of [(3)H] substrates were determined prior to their use as probes in inhibition studies, and ranged from 0.6 to 29 μM for statins. The K(m) of lipophilic simvastatin acid could not be determined due to its high passive permeability that masked OATP1B1 transport, and therefore this statin could not be used as a probe. Estrone 3-sulfate exhibited biphasic kinetics, whereas estradiol 17β-glucuronide demonstrated simple Michaelis-Menton kinetics. AZX moderately inhibited OATP1B1-mediated transport of all statins (IC(50)=4.6-9.7 μM), except fluvastatin, of estradiol 17β-glucuronide (IC(50)=5.3 μM), and weakly inhibited estrone 3-sulfate (IC(50)=79 μM). Rifamycin SV strongly, and gemfibrozil weakly, inhibited the OATP1B1-mediated transport of substrates. Estradiol 17β-glucuronide was identified as a good surrogate probe for statins when assessing OATP1B1 inhibitory potential using this test system. Inhibition data was used to predict the likelihood of a clinical DDI, using current draft US FDA guidance and recommendations of the International Transporter Consortium. Predictions for AZX indicated the potential for an OATP1B1-mediated DDI in vivo and that a clinical interaction study is warranted to confirm whether AZX is an OATP1B1 inhibitor in the clinic.
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Affiliation(s)
- Pradeep Sharma
- Global DMPK, AstraZeneca R&D Alderley Park, Mereside, Macclesfield, Cheshire SK10 4TG, UK.
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Lindqvist L, Robert F, Merrick W, Kakeya H, Fraser C, Osada H, Pelletier J. Inhibition of translation by cytotrienin A--a member of the ansamycin family. RNA 2010; 16:2404-2413. [PMID: 20943818 PMCID: PMC2995401 DOI: 10.1261/rna.2307710] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Accepted: 09/17/2010] [Indexed: 05/30/2023]
Abstract
The ansamycins are a diverse and often physiologically active group of compounds that include geldanamycin and rifamycin, inhibitors of heat shock protein 90 and prokaryotic DNA-dependent RNA synthesis, respectively. Cytotrienin A is an ansamycin-type small molecule with potent antiproliferative and proapoptotic properties. Here, we report that this compound inhibits eukaryotic protein synthesis by targeting translation elongation and interfering with eukaryotic elongation factor 1A function. We also find that cytotrienin A prevents HUVEC tube formation and diminishes microvessel formation in the chorioallantoic membrane assay. These results provide a molecular understanding into cytotrienin A's previously reported properties as an anticancer apoptosis-inducing drug.
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Affiliation(s)
- Lisa Lindqvist
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
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Sayada C. Re: Review article titled, "Rifamycins - Obstacles and opportunities" by Paul A. Aristoff, George A. Garcia, Paul D. Kirchhoff, H.D. Hollis Showalter. Tuberculosis 2010; 90(2):94-118. Tuberculosis (Edinb) 2010; 90:326; author reply 326-7. [PMID: 20691638 DOI: 10.1016/j.tube.2010.07.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Accepted: 07/08/2010] [Indexed: 11/17/2022]
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Abstract
PURPOSE OF REVIEW Rifaximin is gaining attention for its potential activity in a multitude of gastrointestinal diseases. We review the unique pharmaceutical properties of this antibiotic and the published evidence in the literature regarding the use of rifaximin for different gastrointestinal disorders. RECENT FINDINGS Rifaximin is a gastrointestinal-selective antibiotic with a broad spectrum of antimicrobial activity, an excellent safety profile, minimal drug interactions, and negligible impact on the intestinal microbiome. Rifaximin is currently approved in the United States for the treatment of travelers' diarrhea caused by noninvasive diarrheagenic Escherichia coli and is approved in more than 30 other countries for a variety of gastrointestinal disorders. Considerable research with this medication has been conducted for the treatment and prevention of travelers' diarrhea, the treatment of portal systemic encephalopathy, Clostridium difficile infection, small bowel intestinal overgrowth, irritable bowel syndrome, inflammatory bowel disease, pouchitis, and colonic diverticular disease. SUMMARY Rifaximin is effective for the treatment of travelers' diarrhea and can be considered as the treatment of choice for uncomplicated travelers' diarrhea. When invasive travelers' diarrhea pathogens are suspected, an alternative antibiotic should be administered. Rifaximin appears promising as a chemoprophylaxis for travelers' diarrhea and as a treatment of portal systemic encephalopathy. This antibiotic may be effective for other gastrointestinal diseases, but more well designed clinical studies are needed to confirm its efficacy for these off-label indications. Future studies will determine whether the development of significant bacterial resistance will limit rifaximin use.
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Affiliation(s)
- Hoonmo L Koo
- Baylor College of Medicine, Houston, Texas 77030, USA.
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Johnson S, Schriever C, Patel U, Patel T, Hecht DW, Gerding DN. Rifaximin Redux: treatment of recurrent Clostridium difficile infections with rifaximin immediately post-vancomycin treatment. Anaerobe 2009; 15:290-1. [PMID: 19698797 DOI: 10.1016/j.anaerobe.2009.08.004] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2009] [Accepted: 08/10/2009] [Indexed: 01/09/2023]
Abstract
We report our continued experience with rifaximin as a post-vancomycin treatment strategy in six patients with multiple recurrences of C. difficile infection (CDI). Four of the six patients (67%) had no further diarrhea episodes, but two patients failed shortly after or during the rifaximin treatment. C. difficile isolates from one of the two patients who failed treatment had an MIC of >256 microg/ml to rifampin. Serial therapy with vancomycin, followed by rifaximin remains an option for some patients with multiple CDI recurrences.
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Affiliation(s)
- Stuart Johnson
- Research Service, Hines VA Hospital, Hines, IL 60141-3030, USA.
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Abstract
INTRODUCTION The treatment of tuberculosis (TB) is a mature discipline, with more than 60 years of clinical experience accrued across the globe. The requisite Multi-drug treatment of drug-susceptible TB, however, lasts 6 months and has never been optimized according to current standards. Multi-drug resistant TB and TB in individuals coinfected with HIV present additional treatment challenges. OBJECTIVE This article reviews the role that existing drugs and new compounds could have in shortening or improving treatment for TB. The key to treatment shortening seems to be sterilizing activity, or the ability of drugs to kill mycobacteria that persist after the initial days of multi-drug treatment. RESULTS Among existing anti-TB drugs, the rifamycins hold the greatest potential for shortening treatment and improving outcomes, in both HIV-infected and HIV-uninfected populations, without dramatic increases in toxicity. Clinical studies underway or being planned, are supported by in vitro , animal and human evidence of increased sterilizing activity--without significant increases in toxicity--at elevated daily doses. Fluoroquinolones also seem to have significant sterilizing activity. At present, at least two class members are being evaluated for treatment shortening with different combinations of first-line drugs. However, in light of apparent rapid selection for fluoroquinolone-resistant mutants, relative frequency of serious adverse events and a perceived need to 'reserve' fluoroquinolones for the treatment of drug-resistant TB, their exact role in TB treatment remains to be determined. Other possible improvements may come from inhaled delivery or split dosing (linezolid) of anti-TB drugs for which toxicity (ethionamide) or lack of absorption (aminoglycosides and polypeptides) precludes delivery of maximally effective, oral doses, once daily. New classes of drugs with novel mechanisms of action, nitroimidazopyrans and a diarylquinoline, among others, may soon provide opportunities for improving treatment of drug-resistant TB or shortening treatment of drug-susceptible TB. CONCLUSION More potential options for improved TB treatment currently exist than at any other time in the last 30 years. The challenge in TB pharmacotherapy is to devise well-tolerated, efficacious, short-duration regimens that can be used successfully against drug-resistant and drug-resistant TB in a heterogeneous population of patients.
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Affiliation(s)
- Carole D Mitnick
- Department of Global Health & Social Medicine, Harvard Medical School, 643 Huntington Ave., 4th Floor, Boston, MA 02215, USA
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Robertson GT, Bonventre EJ, Doyle TB, Du Q, Duncan L, Morris TW, Roche ED, Yan D, Lynch AS. In vitro evaluation of CBR-2092, a novel rifamycin-quinolone hybrid antibiotic: studies of the mode of action in Staphylococcus aureus. Antimicrob Agents Chemother 2008; 52:2313-23. [PMID: 18443108 PMCID: PMC2443886 DOI: 10.1128/aac.01649-07] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Revised: 03/03/2008] [Accepted: 04/22/2008] [Indexed: 01/12/2023] Open
Abstract
Rifamycins have proven efficacy in the treatment of persistent bacterial infections. However, the frequency with which bacteria develop resistance to rifamycin agents restricts their clinical use to antibiotic combination regimens. In a program directed toward the synthesis of rifamycins with a lower propensity to elicit resistance development, a series of compounds were prepared that covalently combine rifamycin and quinolone pharmacophores to form stable hybrid antibacterial agents. We describe mode-of-action studies with Staphylococcus aureus of CBR-2092, a novel hybrid that combines the rifamycin SV and 4H-4-oxo-quinolizine pharmacophores. In biochemical studies, CBR-2092 exhibited rifampin-like potency as an inhibitor of RNA polymerase, was an equipotent (balanced) inhibitor of DNA gyrase and DNA topoisomerase IV, and retained activity against a prevalent quinolone-resistant variant. Macromolecular biosynthesis studies confirmed that CBR-2092 has rifampin-like effects on RNA synthesis in rifampin-susceptible strains and quinolone-like effects on DNA synthesis in rifampin-resistant strains. Studies of mutant strains that exhibited reduced susceptibility to CBR-2092 further substantiated RNA polymerase as the primary cellular target of CBR-2092, with DNA gyrase and DNA topoisomerase IV being secondary and tertiary targets, respectively, in strains exhibiting preexisting rifampin resistance. In contrast to quinolone comparator agents, no strains with altered susceptibility to CBR-2092 were found to exhibit changes consistent with altered efflux properties. The combined data indicate that CBR-2092 may have potential utility in monotherapy for the treatment of persistent S. aureus infections.
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Raykov ZZ, Vassilev K, Grigorova G, Lyapova A, Alexiev A, Petrov G. Spin-labeled rifamycin: biological activity. Pharmazie 2008; 63:61-66. [PMID: 18271306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
3-[(2,2,6,6-Tetramethylpiperidine-4-ylimino)methyl]rifamycin (4) and spin-labeled rifamycin-3-[(2,2,6,6- tetramethyl-1-oxyl-piperidine-4-ylimino)methyl]rifamycin (1) were prepared. The structures of these compounds were determined by IR, UV, MS and 1H NMR of 4. The ESR-spectrum of 1 is a symmetric triplet signal, characteristic of nitroxyl radicals, g = 2.0025. An in vitro comparative study of the cytotoxicity and antitumor activity of 1, 4 and the initial 3-formyl-rifamycin was carried out in concentrations from 0.1 to 0.001 mM on cells before and after oxidative stress (preliminary irradiation 7Gy) on MH3924A-hepatoma rat cells, 293 transformed human fibroblasts, NBK transformed human fibroblasts and HT 1080 human fibrosarcoma. The compounds showed a cytostatic effect to 85%, with 1 being less toxic in the hepatoma cell line. In human melanoma cell lines 1 showed a higher toxicity than 4. All the derivatives (1 and 4) have in vitro antibacterial activity comparable with that of rifampicin.
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Affiliation(s)
- Z Z Raykov
- German Cancer Research Center, Heidelberg, Germany
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Abstract
BACKGROUND Treatment options for hepatic encephalopathy have disparate risks and benefits. Non-absorbable disaccharides and neomycin are limited by uncertain efficacy and common dose-limiting side effects. In contrast, rifaximin is safe and effective in hepatic encephalopathy, but is more expensive. METHODS We conducted a decision analysis to calculate the cost-effectiveness of six strategies in hepatic encephalopathy: (i) no hepatic encephalopathy treatment, (ii) lactulose monotherapy, (iii) lactitol monotherapy, (iv) neomycin monotherapy, (v) rifaximin monotherapy and (vi) up-front lactulose with crossover to rifaximin if poor response or intolerance of lactulose ('rifaximin salvage'). The primary outcome was cost per quality-adjusted life-year gained. RESULTS Under base-case conditions, 'do nothing' was least effective and rifaximin salvage was most effective. Lactulose monotherapy was least expensive, and rifaximin monotherapy was most expensive. When balancing cost and effectiveness, lactulose monotherapy and rifaximin salvage dominated alternative strategies. Compared to lactulose monotherapy, rifaximin salvage cost an incremental US$2315 per quality-adjusted life-year-gained. The cost of rifaximin had to fall below US$1.03/tab in order for rifaximin monotherapy to dominate lactulose monotherapy. CONCLUSIONS Rifaximin monotherapy is not cost-effective in the treatment of chronic hepatic encephalopathy at current average wholesale prices. However, a hybrid salvage strategy, reserving rifaximin for lactulose-refractory patients, may be highly cost-effective.
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Affiliation(s)
- E Huang
- David Geffen School of Medicine at UCLA, Los Angeles, California, USA
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