101
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Li G, Zhang J, Li C, Guo Q, Jiang Y, Wei J, Qiu Y, Zhao X, Zhao LL, Lu J, Wan K. Antimycobacterial activity of five efflux pump inhibitors against Mycobacterium tuberculosis clinical isolates. J Antibiot (Tokyo) 2015; 69:173-5. [PMID: 26464012 DOI: 10.1038/ja.2015.101] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 08/20/2015] [Accepted: 09/07/2015] [Indexed: 11/09/2022]
Affiliation(s)
- Guilian Li
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Jingrui Zhang
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.,Laboratory, Shijiazhuang Obstetrics and Gynecology Hospital, the Fourth Hospital of Shijiazhuang, Shijiazhuang, China.,Key Laboratory of Laboratory Medicine, Wenzhou Medical College, Wenzhou, China
| | - Chao Li
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.,Key Laboratory of Laboratory Medicine, Wenzhou Medical College, Wenzhou, China
| | - Qian Guo
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.,Pathogenic Biology Institute, University of South China, Hengyang, China
| | - Yi Jiang
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Jianhao Wei
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.,Key Laboratory of Laboratory Medicine, Wenzhou Medical College, Wenzhou, China
| | - Yan Qiu
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Xiuqin Zhao
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Li-li Zhao
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Jianxin Lu
- Key Laboratory of Laboratory Medicine, Wenzhou Medical College, Wenzhou, China
| | - Kanglin Wan
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.,Key Laboratory of Laboratory Medicine, Wenzhou Medical College, Wenzhou, China
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102
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Pooja D, Tunki L, Kulhari H, Reddy BB, Sistla R. Characterization, biorecognitive activity and stability of WGA grafted lipid nanostructures for the controlled delivery of Rifampicin. Chem Phys Lipids 2015; 193:11-7. [PMID: 26409629 DOI: 10.1016/j.chemphyslip.2015.09.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 09/20/2015] [Accepted: 09/22/2015] [Indexed: 11/29/2022]
Abstract
Targeted nanomedicines improve the delivery of drugs by increasing the drug concentration at target site, protecting the premature degradation and releasing the encapsulated drug in controlled manner. To make rifampicin (RFN) delivery more effective, we designed and characterized wheat germ agglutinin (WGA) conjugated, RFN loaded solid-lipid nanoparticles (WRSN). Nanoparticles were prepared by solvent emulsification/evaporation and conjugated with fluorescein isothiocyanate-labeled WGA. Important characteristics, such as particle size, zeta potential, encapsulation efficiency, conjugation efficiency and in vitro drug release behavior, were investigated. WGA conjugation to the nanoparticles was confirmed by Fourier Transform Infrared (FTIR) analysis. Conjugation efficiency was determined by fluorescent spectroscopy and Bradford assay. RFN was released from nanoparticles via the diffusion-controlled, non-fickian and supercase II mechanism. A haemaglutination test confirmed that WGA retained its bio-recognition activity and sugar-binding specificity after it was coupled with the nanoparticles. In vitro experiments demonstrated that WRSN interacted more than non-conjugated nanoparticles with porcine mucin. WRSN were stable in the presence of electrolytes up to 1M concentration. Therefore, WGA-conjugated solid lipid nanoparticles could be a promising tool for the controlled delivery of RFN or other anti-tubercular drugs.
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Affiliation(s)
- Deep Pooja
- Medicinal Chemistry & Pharmacology Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500007, India
| | - Lakshmi Tunki
- Medicinal Chemistry & Pharmacology Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500007, India
| | - Hitesh Kulhari
- Medicinal Chemistry & Pharmacology Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500007, India; IICT-RMIT Research Centre, CSIR-Indian Institute of Chemical Technology, Hyderabad 500007, India; Health Innovations Research Institute, RMIT University, Melbourne, Australia
| | - Bharathi B Reddy
- Medicinal Chemistry & Pharmacology Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500007, India
| | - Ramakrishna Sistla
- Medicinal Chemistry & Pharmacology Division, CSIR-Indian Institute of Chemical Technology, Hyderabad 500007, India.
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103
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Zhai MX, Chen F, Zhao YY, Wu YH, Li GD, Gao YF, Qi YM. Novel epitopes identified from efflux pumps of Mycobacterium tuberculosis could induce cytotoxic T lymphocyte response. PeerJ 2015; 3:e1229. [PMID: 26417538 PMCID: PMC4582945 DOI: 10.7717/peerj.1229] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 08/14/2015] [Indexed: 12/05/2022] Open
Abstract
Overcoming drug-resistance is one of the major challenges to control tuberculosis (TB). The up-regulation of efflux pumps is one common mechanism that leads to drug-resistance. Therefore, immunotherapy targeting these efflux pump antigens could be promising strategy to be combined with current chemotherapy. Considering that CD8+ cytotoxic T lymphocytes (CTLs) induced by antigenic peptides (epitopes) could elicit HLA-restricted anti-TB immune response, efflux pumps from classical ABC family (Mycobacterium tuberculosis, Mtb) were chosen as target antigens to identify CTL epitopes. HLA-A2 restricted candidate peptides from Rv2937, Rv2686c and Rv2687c of Mycobacterium tuberculosis were predicted, synthesized and tested. Five peptides could induce IFN-γ release and cytotoxic activity in PBMCs from HLA-A2+ PPD+ donors. Results from HLA-A2/Kb transgenic mice immunization assay suggested that four peptides Rv2937-p168, Rv2937-p266, Rv2686c-p151, and Rv2686c-p181 could induce significant CTL response in vivo. These results suggested that these novel epitopes could be used as immunotherapy candidates to TB drug-resistance.
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Affiliation(s)
- Ming-Xia Zhai
- School of Life Sciences, Zhengzhou University , Zhengzhou , China
| | - Fei Chen
- School of Life Sciences, Zhengzhou University , Zhengzhou , China
| | - Yuan-Yuan Zhao
- School of Life Sciences, Zhengzhou University , Zhengzhou , China
| | - Ya-Hong Wu
- School of Life Sciences, Zhengzhou University , Zhengzhou , China
| | - Guo-Dong Li
- School of Life Sciences, Zhengzhou University , Zhengzhou , China
| | - Yan-Feng Gao
- School of Life Sciences, Zhengzhou University , Zhengzhou , China
| | - Yuan-Ming Qi
- School of Life Sciences, Zhengzhou University , Zhengzhou , China
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104
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Garneau-Tsodikova S, Labby KJ. Mechanisms of Resistance to Aminoglycoside Antibiotics: Overview and Perspectives. MEDCHEMCOMM 2015; 7:11-27. [PMID: 26877861 DOI: 10.1039/c5md00344j] [Citation(s) in RCA: 272] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Aminoglycoside (AG) antibiotics are used to treat many Gram-negative and some Gram-positive infections and, importantly, multidrug-resistant tuberculosis. Among various bacterial species, resistance to AGs arises through a variety of intrinsic and acquired mechanisms. The bacterial cell wall serves as a natural barrier for small molecules such as AGs and may be further fortified via acquired mutations. Efflux pumps work to expel AGs from bacterial cells, and modifications here too may cause further resistance to AGs. Mutations in the ribosomal target of AGs, while rare, also contribute to resistance. Of growing clinical prominence is resistance caused by ribosome methyltransferases. By far the most widespread mechanism of resistance to AGs is the inactivation of these antibiotics by AG-modifying enzymes. We provide here an overview of these mechanisms by which bacteria become resistant to AGs and discuss their prevalence and potential for clinical relevance.
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Affiliation(s)
- Sylvie Garneau-Tsodikova
- University of Kentucky, Department of Pharmaceutical Sciences, 789 South Limestone Street, Lexington, KY, USA. ; Tel: 859-218-1686
| | - Kristin J Labby
- Beloit College, Department of Chemistry, 700 College Street, Beloit, WI, USA. ; Tel: 608-363-2273
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105
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An update on pathogenesis and management of tuberculosis with special reference to drug resistance. ASIAN PACIFIC JOURNAL OF TROPICAL DISEASE 2015. [DOI: 10.1016/s2222-1808(15)60912-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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106
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Luthuli BB, Purdy GE, Balagaddé FK. Confinement-Induced Drug-Tolerance in Mycobacteria Mediated by an Efflux Mechanism. PLoS One 2015; 10:e0136231. [PMID: 26295942 PMCID: PMC4546595 DOI: 10.1371/journal.pone.0136231] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 07/30/2015] [Indexed: 11/20/2022] Open
Abstract
Tuberculosis (TB) is the world's deadliest curable disease, responsible for an estimated 1.5 million deaths annually. A considerable challenge in controlling this disease is the prolonged multidrug chemotherapy (6 to 9 months) required to overcome drug-tolerant mycobacteria that persist in human tissues, although the same drugs can sterilize genetically identical mycobacteria growing in axenic culture within days. An essential component of TB infection involves intracellular Mycobacterium tuberculosis bacteria that multiply within macrophages and are significantly more tolerant to antibiotics compared to extracellular mycobacteria. To investigate this aspect of human TB, we created a physical cell culture system that mimics confinement of replicating mycobacteria, such as in a macrophage during infection. Using this system, we uncovered an epigenetic drug-tolerance phenotype that appears when mycobacteria are cultured in space-confined bioreactors and disappears in larger volume growth contexts. Efflux mechanisms that are induced in space-confined growth environments contribute to this drug-tolerance phenotype. Therefore, macrophage-induced drug tolerance by mycobacteria may be an effect of confined growth among other macrophage-specific mechanisms.
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Affiliation(s)
- Brilliant B. Luthuli
- KwaZulu-Natal Research Institute for Tuberculosis and HIV, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, 4001, South Africa
| | - Georgiana E. Purdy
- Dept. of Molecular Microbiology and Immunology, Oregon Health and Sciences University, 3181 S. W. Sam Jackson Park Rd., Mail Code L220, Portland, OR, 97239, United States of America
| | - Frederick K. Balagaddé
- KwaZulu-Natal Research Institute for Tuberculosis and HIV, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban, 4001, South Africa
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107
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Sun Z, Xu Y, Sun Y, Liu Y, Zhang X, Huang H, Li C. Ofloxacin resistance in Mycobacterium tuberculosis is associated with efflux pump activity independent of resistance pattern and genotype. Microb Drug Resist 2015; 20:525-32. [PMID: 24940805 DOI: 10.1089/mdr.2013.0171] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Drug-resistance to ofloxacin (OFX) in Mycobacterium tuberculosis is due to missense mutations in gyrA and other factors, such as alterations in the activity of drug efflux pumps. In this study, we identified 8 extensively drug resistant tuberculosis (XDR-TB), 40 multidrug resistant TB (MDR-TB), 38 polydrug resistant TB (PDR-TB), and 16 single OFX-resistant TB from 102 clinical isolates. We tested the effect of three efflux inhibitors, reserpine, verapamil, and carbonyl cyanide m-chlorophenyl hydrazone (CCCP), on changes in the OFX minimum inhibitory concentration (MIC) using Resazurin microtitre assay. These three inhibitors changed the MICs from 2- to 32-fold, with CCCP having the strongest effect. A total of 55%, 74%, and 83% of the tested isolates had changes in MIC of more than two-fold by reserpine, verapamil, and CCCP, respectively. The inhibitors led to similar fold-changes of OFX MICs in the XDR, MDR, PDR, and single OFX-resistant isolates. For each inhibitor, a higher resistance to OFX was associated with the greater efflux pump activity. There were no significant differences in the effect of efflux pump inhibitors upon Beijing and non-Beijing M. tuberculosis genotypes. Taken together, these results indicate that the efflux pump activity was greater in the isolates higher resistant to OFX and had similar effects on isolates with different drug resistant pattern, and had similar effects on Beijing and non-Beijing genotypes.
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Affiliation(s)
- Zhaogang Sun
- Beijing Key Laboratory in Drug Resistant Tuberculosis Research, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing Chest Hospital, Capital Medical University , Beijing, People's Republic of China
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108
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Li N, Chen H, Williams HN. Genome-wide comparative analysis of ABC systems in the Bdellovibrio-and-like organisms. Gene 2015; 562:132-7. [PMID: 25707746 DOI: 10.1016/j.gene.2015.02.062] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 02/14/2015] [Accepted: 02/19/2015] [Indexed: 11/28/2022]
Abstract
Bdellovibrio-and-like organisms (BALOs) are gram-negative, predatory bacteria with wide variations in genome sizes and GC content and ecological habitats. The ATP-binding cassette (ABC) systems have been identified in several prokaryotes, fungi and plants and have a role in transport of materials in and out of cells and in cellular processes. However, knowledge of the ABC systems of BALOs remains obscure. A total of 269 putative ABC proteins were identified in BALOs. The genes encoding these ABC systems occupy nearly 1.3% of the gene content in freshwater Bdellovibrio strains and about 0.7% in their saltwater counterparts. The proteins found belong to 25 ABC system families based on their structural characteristics and functions. Among these, 16 families function as importers, 6 as exporters and 3 are involved in various cellular processes. Eight of these 25 ABC system families were deduced to be the core set of ABC systems conserved in all BALOs. All Bacteriovorax strains have 28 or less ABC systems. On the contrary, the freshwater Bdellovibrio strains have more ABC systems, typically around 51. In the genome of Bdellovibrio exovorus JSS (CP003537.1), 53 putative ABC systems were detected, representing the highest number among all the BALO genomes examined in this study. Unexpected high numbers of ABC systems involved in cellular processes were found in all BALOs. Phylogenetic analysis suggests that the majority of ABC proteins can be assigned into many separate families with high bootstrap supports (>50%). In this study, a general framework of sequence-structure-function connections for the ABC systems in BALOs was revealed providing novel insights for future investigations.
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Affiliation(s)
- Nan Li
- School of the Environment, Florida A&M University, Tallahassee, FL, USA
| | - Huan Chen
- National High Magnetic Field Laboratory, Tallahassee, FL, USA
| | - Henry N Williams
- School of the Environment, Florida A&M University, Tallahassee, FL, USA.
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109
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Coelho T, Machado D, Couto I, Maschmann R, Ramos D, von Groll A, Rossetti ML, Silva PA, Viveiros M. Enhancement of antibiotic activity by efflux inhibitors against multidrug resistant Mycobacterium tuberculosis clinical isolates from Brazil. Front Microbiol 2015; 6:330. [PMID: 25972842 PMCID: PMC4412083 DOI: 10.3389/fmicb.2015.00330] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 04/01/2015] [Indexed: 11/25/2022] Open
Abstract
Drug resistant tuberculosis continues to increase and new approaches for its treatment are necessary. The identification of M. tuberculosis clinical isolates presenting efflux as part of their resistant phenotype has a major impact in tuberculosis treatment. In this work, we used a checkerboard procedure combined with the tetrazolium microplate-based assay (TEMA) to study single combinations between antituberculosis drugs and efflux inhibitors (EIs) against multidrug resistant M. tuberculosis clinical isolates using the fully susceptible strain H37Rv as reference. Efflux activity was studied on a real-time basis by a fluorometric method that uses ethidium bromide as efflux substrate. Quantification of efflux pump genes mRNA transcriptional levels were performed by RT-qPCR. The fractional inhibitory concentrations (FIC) indicated synergistic activity for the interactions between isoniazid, rifampicin, amikacin, ofloxacin, and ethidium bromide plus the EIs verapamil, thioridazine and chlorpromazine. The FICs ranged from 0.25, indicating a four-fold reduction on the MICs, to 0.015, 64-fold reduction. The detection of active efflux by real-time fluorometry showed that all strains presented intrinsic efflux activity that contributes to the overall resistance which can be inhibited in the presence of the EIs. The quantification of the mRNA levels of the most important efflux pump genes on these strains shows that they are intrinsically predisposed to expel toxic compounds as the exposure to subinhibitory concentrations of antibiotics were not necessary to increase the pump mRNA levels when compared with the non-exposed counterpart. The results obtained in this study confirm that the intrinsic efflux activity contributes to the overall resistance in multidrug resistant clinical isolates of M. tuberculosis and that the inhibition of efflux pumps by the EIs can enhance the clinical effect of antibiotics that are their substrates.
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Affiliation(s)
- Tatiane Coelho
- Fundação Estadual de Produção e Pesquisa em Saúde, Centro de Desenvolvimento Científico e Tecnológico Porto Alegre, Brazil ; Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul Porto Alegre, Brazil
| | - Diana Machado
- Grupo de Micobactérias, Unidade de Microbiologia Médica, Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa Lisboa, Portugal
| | - Isabel Couto
- Grupo de Micobactérias, Unidade de Microbiologia Médica, Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa Lisboa, Portugal
| | - Raquel Maschmann
- Fundação Estadual de Produção e Pesquisa em Saúde, Centro de Desenvolvimento Científico e Tecnológico Porto Alegre, Brazil ; Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul Porto Alegre, Brazil
| | - Daniela Ramos
- Faculdade de Medicina, Núcleo de Pesquisa em Microbiologia Médica, Universidade Federal do Rio Grande Rio Grande, Brazil
| | - Andrea von Groll
- Faculdade de Medicina, Núcleo de Pesquisa em Microbiologia Médica, Universidade Federal do Rio Grande Rio Grande, Brazil
| | - Maria L Rossetti
- Fundação Estadual de Produção e Pesquisa em Saúde, Centro de Desenvolvimento Científico e Tecnológico Porto Alegre, Brazil ; Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul Porto Alegre, Brazil
| | - Pedro A Silva
- Faculdade de Medicina, Núcleo de Pesquisa em Microbiologia Médica, Universidade Federal do Rio Grande Rio Grande, Brazil
| | - Miguel Viveiros
- Grupo de Micobactérias, Unidade de Microbiologia Médica, Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa Lisboa, Portugal
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110
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Li G, Zhang J, Guo Q, Jiang Y, Wei J, Zhao LL, Zhao X, Lu J, Wan K. Efflux pump gene expression in multidrug-resistant Mycobacterium tuberculosis clinical isolates. PLoS One 2015; 10:e0119013. [PMID: 25695504 PMCID: PMC4335044 DOI: 10.1371/journal.pone.0119013] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 01/09/2015] [Indexed: 11/19/2022] Open
Abstract
Isoniazid (INH) and rifampicin (RIF) are the two most effective drugs in tuberculosis therapy. Understanding the molecular mechanisms of resistance to these two drugs is essential to quickly diagnose multidrug-resistant (MDR) tuberculosis and extensive drug-resistant tuberculosis. Nine clinical Mycobacterium tuberculosis isolates resistant to only INH and RIF and 10 clinical pan-sensitive isolates were included to evaluate the expression of 20 putative drug efflux pump genes and sequence mutations in rpoB (RIF), katG (INH), the inhA promoter (INH), and oxyR-ahpC (INH). Nine and three MDR isolates were induced to overexpress efflux pump genes by INH and RIF, respectively. Eight and two efflux pump genes were induced to overexpress by INH and RIF in MDR isolates, respectively. drrA, drrB, efpA, jefA (Rv2459), mmr, Rv0849, Rv1634, and Rv1250 were overexpressed under INH or RIF stress. Most efflux pump genes were overexpressed under INH stress in a MDR isolates that carried the wild-type katG, inhA, and oxyR-ahpC associated with INH resistance than in those that carried mutations. The expression levels of 11 genes (efpA, Rv0849, Rv1250, P55 (Rv1410c), Rv1634, Rv2994, stp, Rv2459, pstB, drrA, and drrB) without drug inducement were significantly higher (P < 0.05) in nine MDR isolates than in 10 pan-sensitive isolates. In conclusion, efflux pumps may play an important role in INH acquired resistance in MDR M. tuberculosis, especially in those strains having no mutations in genes associated with INH resistance; basal expression levels of some efflux pump genes are higher in MDR isolates than in pan-sensitive isolates and the basal expressional differences may be helpful to diagnose and treat resistant tuberculosis.
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Affiliation(s)
- Guilian Li
- Tuberculosis Branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou 310003, China
| | - Jingrui Zhang
- Tuberculosis Branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou 310003, China
- Key Lab of Laboratory Medicine, Wenzhou Medical College, Wenzhou 325035, Zhejiang, China
- Laboratory, Shijiazhuang Gynecological and Obstetric Hospital, Shijiazhuang, Hebei, 050000, China
| | - Qian Guo
- Tuberculosis Branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou 310003, China
- Pathogenic Biology Institute, South of China University, Hengyang, Hunan 421001, China
| | - Yi Jiang
- Tuberculosis Branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou 310003, China
| | - Jianhao Wei
- Tuberculosis Branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou 310003, China
- Key Lab of Laboratory Medicine, Wenzhou Medical College, Wenzhou 325035, Zhejiang, China
| | - Li-li Zhao
- Tuberculosis Branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou 310003, China
| | - Xiuqin Zhao
- Tuberculosis Branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou 310003, China
| | - Jianxin Lu
- Key Lab of Laboratory Medicine, Wenzhou Medical College, Wenzhou 325035, Zhejiang, China
| | - Kanglin Wan
- Tuberculosis Branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou 310003, China
- * E-mail:
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111
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Li G, Zhang J, Guo Q, Wei J, Jiang Y, Zhao X, Zhao LL, Liu Z, Lu J, Wan K. Study of efflux pump gene expression in rifampicin-monoresistant Mycobacterium tuberculosis clinical isolates. J Antibiot (Tokyo) 2015; 68:431-5. [PMID: 25690361 DOI: 10.1038/ja.2015.9] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2014] [Revised: 10/28/2014] [Accepted: 01/19/2015] [Indexed: 11/09/2022]
Abstract
Rifampicin (RIF) resistance is a risk factor for poor outcome in tuberculosis (TB). In Mycobacterium tuberculosis, both target gene mutation and efflux pumps have major roles in the resistance to anti-TB drugs. This study aimed to determine whether RIF induces efflux pump activation in RIF-monoresistant M. tuberculosis strains. Here, we took advantage of 16 RIF-monoresistant M. tuberculosis clinical isolates to evaluate the expression of 27 putative drug efflux pump genes and measured the influence of four drug efflux pump inhibitors, carbonyl cyanide m-chlorophenyl hydrazone (CCCP), verapamil (VP), thioridazine (TZ) and chlorpromazine (CPZ), on the RIF MICs of these strains. Eight of the 16 RIF-monoresistant isolates carried mutations in rpoB and overexpressed one or two of the following putative efflux pump genes: Rv2333, drrB, drrC, Rv0842, bacA and efpA. CCCP, VP, TZ and CPZ lowered the RIF MICs greater than fourfold in 6, 12, 9 and 12 isolates, respectively. The lowered RIF MICs by VP and CPZ were identical and stronger than CCCP (P-values were all 0.033). In conclusion, the efflux pumps Rv2333, DrrB, DrrC, Rv0842, BacA and EfpA may have a role in RIF resistance in addition to classical mutations in the rpoB gene, and the addition of VP and CPZ could significantly increase RIF susceptibility in RIF-monoresistant M. tuberculosis.
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Affiliation(s)
- Guilian Li
- 1] Tuberculosis branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China [2] Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Jingrui Zhang
- 1] Tuberculosis branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China [2] Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China [3] Key Lab of Laboratory Medicine, Wenzhou Medical College, Wenzhou, Zhejiang, China [4] Laboratory, Gynecological and Obstetric Hospital in Shi Jiazhuang, Hebei, China
| | - Qian Guo
- 1] Tuberculosis branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China [2] Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China [3] Pathogenic Biology Institute, South of China University, Hengyang, Hunan, China
| | - Jianhao Wei
- 1] Tuberculosis branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China [2] Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China [3] Key Lab of Laboratory Medicine, Wenzhou Medical College, Wenzhou, Zhejiang, China
| | - Yi Jiang
- 1] Tuberculosis branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China [2] Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Xiuqin Zhao
- 1] Tuberculosis branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China [2] Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Li-Li Zhao
- 1] Tuberculosis branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China [2] Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Zhiguang Liu
- 1] Tuberculosis branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China [2] Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Jianxin Lu
- Key Lab of Laboratory Medicine, Wenzhou Medical College, Wenzhou, Zhejiang, China
| | - Kanglin Wan
- 1] Tuberculosis branch, State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China [2] Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
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Uchiya KI, Takahashi H, Nakagawa T, Yagi T, Moriyama M, Inagaki T, Ichikawa K, Nikai T, Ogawa K. Characterization of a novel plasmid, pMAH135, from Mycobacterium avium subsp. hominissuis. PLoS One 2015; 10:e0117797. [PMID: 25671431 PMCID: PMC4324632 DOI: 10.1371/journal.pone.0117797] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 12/31/2014] [Indexed: 11/19/2022] Open
Abstract
Mycobacterium avium complex (MAC) causes mainly two types of disease. The first is disseminated disease in immunocompromised hosts, such as individuals infected by human immunodeficiency virus (HIV). The second is pulmonary disease in individuals without systemic immunosuppression, and the incidence of this type is increasing worldwide. M. avium subsp. hominissuis, a component of MAC, causes infection in pigs as well as in humans. Many aspects of the different modes of M. avium infection and its host specificity remain unclear. Here, we report the characteristics and complete sequence of a novel plasmid, designated pMAH135, derived from M. avium strain TH135 in an HIV-negative patient with pulmonary MAC disease. The pMAH135 plasmid consists of 194,711 nucleotides with an average G + C content of 66.5% and encodes 164 coding sequences (CDSs). This plasmid was unique in terms of its homology to other mycobacterial plasmids. Interestingly, it contains CDSs with sequence homology to mycobactin biosynthesis proteins and type VII secretion system-related proteins, which are involved in the pathogenicity of mycobacteria. It also contains putative conserved domains of the multidrug efflux transporter. Screening of isolates from humans and pigs for genes located on pMAH135 revealed that the detection rate of these genes was higher in clinical isolates from pulmonary MAC disease patients than in those from HIV-positive patients, whereas the genes were almost entirely absent in isolates from pigs. Moreover, variable number tandem repeats typing analysis showed that isolates carrying pMAH135 genes are grouped in a specific cluster. Collectively, the pMAH135 plasmid contains genes associated with M. avium's pathogenicity and resistance to antimicrobial agents. The results of this study suggest that pMAH135 influence not only the pathological manifestations of MAC disease, but also the host specificity of MAC infection.
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Affiliation(s)
- Kei-ichi Uchiya
- Department of Microbiology, Faculty of Pharmacy, Meijo University, Nagoya, Japan
- * E-mail:
| | - Hiroyasu Takahashi
- Department of Pharmacy, Kainan Hospital Aichi Prefectural Welfare Federation of Agricultural Cooperatives, Yatomi, Japan
| | - Taku Nakagawa
- Department of Clinical Research, National Hospital Organization, Higashi Nagoya National Hospital, Nagoya, Japan
- Department of Pulmonary Medicine, National Hospital Organization, Higashi Nagoya National Hospital, Nagoya, Japan
| | - Tetsuya Yagi
- Department of Infectious Diseases, Center of National University Hospital for Infection Control, Nagoya University Hospital, Nagoya, Japan
| | - Makoto Moriyama
- Department of Microbiology, Faculty of Pharmacy, Meijo University, Nagoya, Japan
- Department of Pharmacy, National Hospital Organization, Toyohashi Medical Center, Toyohashi, Japan
| | - Takayuki Inagaki
- Department of Microbiology, Faculty of Pharmacy, Meijo University, Nagoya, Japan
- Department of Pharmacy, Nagoya University Hospital, Nagoya, Japan
| | - Kazuya Ichikawa
- Department of Pharmacy, Nagoya University Hospital, Nagoya, Japan
| | - Toshiaki Nikai
- Department of Microbiology, Faculty of Pharmacy, Meijo University, Nagoya, Japan
| | - Kenji Ogawa
- Department of Clinical Research, National Hospital Organization, Higashi Nagoya National Hospital, Nagoya, Japan
- Department of Pulmonary Medicine, National Hospital Organization, Higashi Nagoya National Hospital, Nagoya, Japan
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Combination of amikacin and doxycycline against multidrug-resistant and extensively drug-resistant tuberculosis. Int J Antimicrob Agents 2015; 45:406-12. [PMID: 25717028 DOI: 10.1016/j.ijantimicag.2014.11.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 10/31/2014] [Accepted: 11/23/2014] [Indexed: 12/23/2022]
Abstract
The objective of this study was to assess the activity of amikacin in combination with doxycycline against clinical strains of Mycobacterium tuberculosis in the search for new strategies against multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis. The study included 28 clinical M. tuberculosis strains, comprising 5 fully susceptible, 1 isoniazid-resistant, 17 MDR, 1 poly-resistant (streptomycin/isoniazid), 1 rifampicin-resistant and 3 XDR isolates, as well as the laboratory strain M. tuberculosis H37Rv. Minimum inhibitory concentrations (MICs) were determined using a modified chequerboard methodology in a BACTEC™ MGIT™ 960 System. Fractional inhibitory concentration indices (FICIs) were calculated, and synergy, indifference or antagonism was assessed. Whole-genome sequencing was performed to investigate the genetic basis of synergy, indifference or antagonism. The MIC50 and MIC90 values (MICs that inhibit 50% and 90% of the isolates, respectively) were, respectively, 0.5 mg/L and 1.0 mg/L for amikacin and 8 mg/L and 16 mg/L for doxycycline. The combination of amikacin and doxycycline showed a synergistic effect in 18 of the 29 strains tested and indifference in 11 strains. Antagonism was not observed. A streptomycin resistance mutation (K43R) was associated with indifference. In conclusion, the benefit of addition of doxycycline to an amikacin-containing regimen should be explored since in vitro results in this study indicate either synergy or indifference. Moreover, doxycycline also has immunomodulatory effects.
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114
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Differential expression of efflux pump genes of Mycobacterium tuberculosis in response to varied subinhibitory concentrations of antituberculosis agents. Tuberculosis (Edinb) 2015; 95:155-61. [PMID: 25680943 DOI: 10.1016/j.tube.2015.01.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Accepted: 01/13/2015] [Indexed: 12/15/2022]
Abstract
Several reports have elaborated on the role of efflux pumps in drug resistance in Mycobacterium tuberculosis by analysing the mRNA expression profiles. However, there is no uniformity in the subinhibitory concentrations of drugs chosen in these studies. Some investigators studied the expression of efflux pumps under a drug concentration of 1/2 minimum inhibitory concentration (MIC), while others used 1/3, 1/4 or 1/8MIC. The present study was planned to understand the effect of different concentrations of antituberculosis drugs on the expression of efflux pump genes. Log phase culture of the laboratory strain M. tuberculosis H37Rv was exposed to rifampicin (RIF), isoniazid (INH), streptomycin (SM) and ethambutol (EMB) at different drug concentrations (1/2MIC, 1/3MIC and 1/4MIC). The expression of 10 putative efflux pump genes was studied using quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). We observed an optimal expression of efflux pumps at higher concentrations of INH; and at lower concentrations of RIF and EMB. However, in the presence of SM, a decreased expression of efflux genes with increasing concentrations of the drug was confounded by a significant reduction in Colony Forming Units (CFU).
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Abstract
The intrinsic resistance of mycobacteria to most antimicrobial agents is mainly attributed to the synergy between their relatively impermeable cell wall and efflux systems. The mycobacterial cell wall is rich in lipids and polysaccharides making a compact envelope that limits drug uptake. Changes in cell wall composition or structure lead to variations in susceptibility to drugs. Bacterial efflux pumps are membrane proteins that are capable of actively transporting a broad range of substrates, including drugs, from the cytoplasm to the extracellular environment. Increased expression of efflux pump genes confers a low level resistance phenotype, and under these conditions, bacteria may have greater chances of acquiring chromosomal mutation(s) conferring higher levels of drug resistance. In order to develop effective antimycobacterial therapeutic strategies, the contributions to drug resistance made by the limited permeability of the cell wall and the increased expression of efflux pumps must be understood. In this chapter, we describe a method that allows: (1) the quantification of general efflux activity of mycobacterial strains (clinical isolates, mutants impaired in efflux or permeability) by the study of the transport (influx and efflux) of fluorescent compounds, such as ethidium bromide; and (2) the screening of compounds in search of inhibitors of efflux pumps, which could restore the effectiveness of antimicrobials that are subject to efflux.
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Affiliation(s)
- Liliana Rodrigues
- Grupo de Genética de Micobacterias, Departamento de Microbiología, Medicina Preventiva y Salud Publica, Facultad de Medicina, Universidad de Zaragoza, C/ Domingo Miral s/n, Zaragoza, 50009, Spain
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Padwal P, Bandyopadhyaya R, Mehra S. Polyacrylic acid-coated iron oxide nanoparticles for targeting drug resistance in mycobacteria. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:15266-15276. [PMID: 25375643 DOI: 10.1021/la503808d] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The emergence of drug resistance is a major problem faced in current tuberculosis (TB) therapy, representing a global health concern. Mycobacterium is naturally resistant to most drugs due to export of the latter outside bacterial cells by active efflux pumps, resulting in a low intracellular drug concentration. Thus, development of agents that can enhance the effectiveness of drugs used in TB treatment and bypass the efflux mechanism is crucial. In this study, we present a new nanoparticle-based strategy for enhancing the efficacy of existing drugs. To that end, we have developed poly(acrylic acid) (PAA)-coated iron oxide (magnetite) nanoparticles (PAA-MNPs) as efflux inhibitors and used it together with rifampicin (a first line anti-TB drug) on Mycobacterium smegmatis. PAA-MNPs of mean diameter 9 nm interact with bacterial cells via surface attachment and are then internalized by cells. Although PAA-MNP alone does not inhibit cell growth, treatment of cells with a combination of PAA-MNP and rifampicin exhibits a synergistic 4-fold-higher growth inhibition compared to rifampicin alone. This is because the combination of PAA-MNP and rifampicin results in up to a 3-fold-increased accumulation of rifampicin inside the cells. This enhanced intracellular drug concentration has been explained by real-time transport studies on a common efflux pump substrate, ethidium bromide (EtBr). It is seen that PAA-MNP increases the accumulation of EtBr significantly and also minimizes the EtBr efflux in direct proportion to the PAA-MNP concentration. Our results thus illustrate that the addition of PAA-MNP with rifampicin may bypass the innate drug resistance mechanism of M. smegmatis. This generic strategy is also found to be successful for other anti-TB drugs, such as isoniazid and fluoroquinolones (e.g., norfloxacin), only when stabilized, coated nanoparticles (such as PAA-MNP) are used, not PAA or MNP alone. We hence establish coated nanoparticles as a new class of efflux inhibitors for potential therapeutic use.
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Affiliation(s)
- Priyanka Padwal
- Department of Chemical Engineering, Indian Institute of Technology Bombay , Powai, Mumbai 400076, India
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117
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The efflux pump inhibitor timcodar improves the potency of antimycobacterial agents. Antimicrob Agents Chemother 2014; 59:1534-41. [PMID: 25534740 DOI: 10.1128/aac.04271-14] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previous studies indicated that inhibition of efflux pumps augments tuberculosis therapy. In this study, we used timcodar (formerly VX-853) to determine if this efflux pump inhibitor could increase the potency of antituberculosis (anti-TB) drugs against Mycobacterium tuberculosis in in vitro and in vivo combination studies. When used alone, timcodar weakly inhibited M. tuberculosis growth in broth culture (MIC, 19 μg/ml); however, it demonstrated synergism in drug combination studies with rifampin, bedaquiline, and clofazimine but not with other anti-TB agents. When M. tuberculosis was cultured in host macrophage cells, timcodar had about a 10-fold increase (50% inhibitory concentration, 1.9 μg/ml) in the growth inhibition of M. tuberculosis and demonstrated synergy with rifampin, moxifloxacin, and bedaquiline. In a mouse model of tuberculosis lung infection, timcodar potentiated the efficacies of rifampin and isoniazid, conferring 1.0 and 0.4 log10 reductions in bacterial burden in lung, respectively, compared to the efficacy of each drug alone. Furthermore, timcodar reduced the likelihood of a relapse infection when evaluated in a mouse model of long-term, chronic infection with treatment with a combination of rifampin, isoniazid, and timcodar. Although timcodar had no effect on the pharmacokinetics of rifampin in plasma and lung, it did increase the plasma exposure of bedaquiline. These data suggest that the antimycobacterial drug-potentiating activity of timcodar is complex and drug dependent and involves both bacterial and host-targeted mechanisms. Further study of the improvement of the potency of antimycobacterial drugs and drug candidates when used in combination with timcodar is warranted.
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118
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Davis TD, Gerry CJ, Tan DS. General platform for systematic quantitative evaluation of small-molecule permeability in bacteria. ACS Chem Biol 2014; 9:2535-44. [PMID: 25198656 PMCID: PMC4245172 DOI: 10.1021/cb5003015] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The chemical features that impact small-molecule permeability across bacterial membranes are poorly understood, and the resulting lack of tools to predict permeability presents a major obstacle to the discovery and development of novel antibiotics. Antibacterials are known to have vastly different structural and physicochemical properties compared to nonantiinfective drugs, as illustrated herein by principal component analysis (PCA). To understand how these properties influence bacterial permeability, we have developed a systematic approach to evaluate the penetration of diverse compounds into bacteria with distinct cellular envelopes. Intracellular compound accumulation is quantitated using LC-MS/MS, then PCA and Pearson pairwise correlations are used to identify structural and physicochemical parameters that correlate with accumulation. An initial study using 10 sulfonyladenosines in Escherichia coli, Bacillus subtilis, and Mycobacterium smegmatis has identified nonobvious correlations between chemical structure and permeability that differ among the various bacteria. Effects of cotreatment with efflux pump inhibitors were also investigated. This sets the stage for use of this platform in larger prospective analyses of diverse chemotypes to identify global relationships between chemical structure and bacterial permeability that would enable the development of predictive tools to accelerate antibiotic drug discovery.
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Affiliation(s)
- Tony D. Davis
- Pharmacology Program−Weill Cornell Graduate School of Medical Sciences, ‡Gerstner Sloan Kettering Summer Undergraduate Research Program, §Molecular Pharmacology & Chemistry Program and Tri-Institutional Research Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, Box 422, New York, New York 10065, United States
| | - Christopher J. Gerry
- Pharmacology Program−Weill Cornell Graduate School of Medical Sciences, ‡Gerstner Sloan Kettering Summer Undergraduate Research Program, §Molecular Pharmacology & Chemistry Program and Tri-Institutional Research Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, Box 422, New York, New York 10065, United States
| | - Derek S. Tan
- Pharmacology Program−Weill Cornell Graduate School of Medical Sciences, ‡Gerstner Sloan Kettering Summer Undergraduate Research Program, §Molecular Pharmacology & Chemistry Program and Tri-Institutional Research Program, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, Box 422, New York, New York 10065, United States
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119
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Suriyanarayanan B, Sarojini Santhosh R. Docking analysis insights quercetin can be a non-antibiotic adjuvant by inhibiting Mmr drug efflux pump in Mycobacterium sp. and its homologue EmrE in Escherichia coli. J Biomol Struct Dyn 2014; 33:1819-34. [PMID: 25297690 DOI: 10.1080/07391102.2014.974211] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Drug efflux pumps (EP) like Mmr in Mycobacterium transported drugs out of cell, a main reason for drug resistance developing in Mycobacterium tuberculosis. In this in silico study, mainly analysed EP inhibitory potential of a plant-derived flavonoid, quercetin, through docking analysis. Mmr present in Mycobacterium smegmatis and M. tuberculosis, and its homologue EmrE of Escherichia coli was used. Initially, homology modelling of EP monomers and dimers constructed from M. smegmatis, M. tuberculosis and E. coli; the stabilities of models were analysed from Ramachandran plots prepared in PROCHECK. Docking analysis of quercetin with EP protein showed that in all three organisms, the residues for function and stability are important and quercetin had best interactions comparing to compounds such as, verapamil, reserpine, chlorpromazine, Carbonyl Cyanide m- Chloro Phenylhydrazone. Molecular dynamics and simulation studies showed that during the entire course of simulation quercetin-Mmr complex were stable. It insights quercetin can act as a non-antibiotic adjuvant for treatment of tuberculosis by bring down the efflux of drug from bacteria.
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Affiliation(s)
- Balasubramanian Suriyanarayanan
- a Centre for Research on Infectious Diseases , School of Chemical and Biotechnology, SASTRA University , Thanjavur 613401 , India
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120
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Vashisht R, Bhat AG, Kushwaha S, Bhardwaj A, Consortium OSDD, Brahmachari SK. Systems level mapping of metabolic complexity in Mycobacterium tuberculosis to identify high-value drug targets. J Transl Med 2014; 12:263. [PMID: 25304862 PMCID: PMC4201925 DOI: 10.1186/s12967-014-0263-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 09/11/2014] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND The effectiveness of current therapeutic regimens for Mycobacterium tuberculosis (Mtb) is diminished by the need for prolonged therapy and the rise of drug resistant/tolerant strains. This global health threat, despite decades of basic research and a wealth of legacy knowledge, is due to a lack of systems level understanding that can innovate the process of fast acting and high efficacy drug discovery. METHODS The enhanced functional annotations of the Mtb genome, which were previously obtained through a crowd sourcing approach was used to reconstruct the metabolic network of Mtb in a bottom up manner. We represent this information by developing a novel Systems Biology Spindle Map of Metabolism (SBSM) and comprehend its static and dynamic structure using various computational approaches based on simulation and design. RESULTS The reconstructed metabolism of Mtb encompasses 961 metabolites, involved in 1152 reactions catalyzed by 890 protein coding genes, organized into 50 pathways. By accounting for static and dynamic analysis of SBSM in Mtb we identified various critical proteins required for the growth and survival of bacteria. Further, we assessed the potential of these proteins as putative drug targets that are fast acting and less toxic. Further, we formulate a novel concept of metabolic persister genes (MPGs) and compared our predictions with published in vitro and in vivo experimental evidence. Through such analyses, we report for the first time that de novo biosynthesis of NAD may give rise to bacterial persistence in Mtb under conditions of metabolic stress induced by conventional anti-tuberculosis therapy. We propose such MPG's as potential combination of drug targets for existing antibiotics that can improve their efficacy and efficiency for drug tolerant bacteria. CONCLUSION The systems level framework formulated by us to identify potential non-toxic drug targets and strategies to circumvent the issue of bacterial persistence can substantially aid in the process of TB drug discovery and translational research.
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Affiliation(s)
- Rohit Vashisht
- />CSIR-Open Source Drug Discovery Unit, New Delhi, India
- />Academy of Scientific and Innovative Research, New Delhi, India
| | - Ashwini G Bhat
- />CSIR-Open Source Drug Discovery Unit, New Delhi, India
| | | | - Anshu Bhardwaj
- />CSIR-Open Source Drug Discovery Unit, New Delhi, India
| | - OSDD Consortium
- />CSIR-Open Source Drug Discovery Unit, New Delhi, India
- />Academy of Scientific and Innovative Research, New Delhi, India
- />CSIR - Institute of Genomics and Integrative Biology, New Delhi, India
| | - Samir K Brahmachari
- />CSIR-Open Source Drug Discovery Unit, New Delhi, India
- />Academy of Scientific and Innovative Research, New Delhi, India
- />CSIR - Institute of Genomics and Integrative Biology, New Delhi, India
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Pedgaonkar GS, Sridevi JP, Jeankumar VU, Saxena S, Devi PB, Renuka J, Yogeeswari P, Sriram D. Development of 2-(4-oxoquinazolin-3(4H)-yl)acetamide derivatives as novel enoyl-acyl carrier protein reductase (InhA) inhibitors for the treatment of tuberculosis. Eur J Med Chem 2014; 86:613-27. [DOI: 10.1016/j.ejmech.2014.09.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Revised: 08/05/2014] [Accepted: 09/08/2014] [Indexed: 10/24/2022]
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122
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Samala G, Madhuri C, Sridevi JP, Nallangi R, Perumal Y, Dharmarajan S. Synthesis and antitubercular evaluation of 2-iminothiazolidine-4-ones. ACTA ACUST UNITED AC 2014. [DOI: 10.5155/eurjchem.5.3.550-556.1059] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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123
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Development of benzo[d]oxazol-2(3H)-ones derivatives as novel inhibitors of Mycobacterium tuberculosis InhA. Bioorg Med Chem 2014; 22:6134-45. [PMID: 25282650 DOI: 10.1016/j.bmc.2014.08.031] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 08/21/2014] [Accepted: 08/26/2014] [Indexed: 11/21/2022]
Abstract
A series of twenty seven substituted 2-(2-oxobenzo[d]oxazol-3(2H)-yl)acetamide derivatives were designed based on our earlier reported Mycobacterium tuberculosis (MTB) enoyl-acyl carrier protein reductase (InhA) lead. Compounds were evaluated for MTB InhA inhibition study, in vitro activity against drug-sensitive and -resistant MTB strains, and cytotoxicity against RAW 264.7 cell line. Among the compounds tested, 2-(6-nitro-2-oxobenzo[d]oxazol-3(2H)-yl)-N-(5-nitrothiazol-2-yl)acetamide (30) was found to be the most promising compound with IC50 of 5.12 ± 0.44 μM against MTB InhA, inhibited drug sensitive MTB with MIC 17.11 μM and was non-cytotoxic at 100 μM. The interaction with protein and enhancement of protein stability in complex with compound 30 was further confirmed biophysically by differential scanning fluorimetry.
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A novel marRAB operon contributes to the rifampicin resistance in Mycobacterium smegmatis. PLoS One 2014; 9:e106016. [PMID: 25153492 PMCID: PMC4143341 DOI: 10.1371/journal.pone.0106016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 07/25/2014] [Indexed: 12/30/2022] Open
Abstract
The multiple-antibiotic resistance regulator (MarR) plays an important role in modulating bacterial antibiotic resistance. However, the regulatory model of the marRAB operon in mycobacteria remains to be characterized. Here we report that a MarR, encoded by Ms6508, and its marRAB operon specifically contribute to rifampicin (RIF) resistance in Mycobacterium smegmatis. We show that the MarR recognizes a conserved 21-bp palindromic motif and negatively regulates the expression of two ABC transporters in the operon, encoded by Ms6509–6510. Unlike other known drug efflux pumps, overexpression of these two ABC transporters unexpectedly increased RIF sensitivity and deletion of these two genes increased mycobacterial resistance to the antibiotic. No change can be detected for the sensitivity of recombinant mycobacterial strains to three other anti-TB drugs. Furthermore, HPLC experiments suggested that Ms6509–Ms6510 could pump RIF into the mycobacterial cells. These findings indicated that the mycobacterial MarR functions as a repressor and constitutively inhibits the expression of the marRAB operon, which specifically contributes to RIF resistance in M. smegmatis. Therefore, our data suggest a new regulatory mechanism of RIF resistance and also provide the new insight into the regulatory model of a marRAB operon in mycobacteria.
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125
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Devi PB, Samala G, Sridevi JP, Saxena S, Alvala M, Salina EG, Sriram D, Yogeeswari P. Structure-guided design of thiazolidine derivatives as Mycobacterium tuberculosis pantothenate synthetase inhibitors. ChemMedChem 2014; 9:2538-47. [PMID: 25155986 DOI: 10.1002/cmdc.201402171] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Indexed: 11/07/2022]
Abstract
The pantothenate biosynthetic pathway is essential for the persistent growth and virulence of Mycobacterium tuberculosis (Mtb) and one of the enzymes in the pathway, pantothenate synthetase (PS, EC: 6.3.2.1), encoded by the panC gene, has become an appropriate target for new therapeutics to treat tuberculosis. Herein, we report nanomolar thiazolidine inhibitors of Mtb PS developed by a rational inhibitor design approach. The thiazolidine compounds were discovered by using energy-based pharmacophore modelling and subsequent in vitro screening, which resulted in compounds with a half maximal inhibitory concentration (IC50) value of (1.12 ± 0.12) μM. These compounds were subsequently optimised by a combination of modelling and synthetic chemistry. Hit expansion of the lead by chemical synthesis led to an improved inhibitor with an IC50 value of 350 nM and an Mtb minimum inhibitory concentration (MIC) of 1.55 μM. Some of these compounds also showed good activity against dormant Mtb cells.
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Affiliation(s)
- Parthiban Brindha Devi
- Drug Discovery Research Laboratory, Department of Pharmacy, Birla Institute of Technology and Science-Pilani, Hyderabad Campus, Hyderabad-500078 (India)
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Lirio SB, Macabeo APG, Paragas EM, Knorn M, Kohls P, Franzblau SG, Wang Y, Aguinaldo MAM. Antitubercular constituents from Premna odorata Blanco. JOURNAL OF ETHNOPHARMACOLOGY 2014; 154:471-474. [PMID: 24768632 DOI: 10.1016/j.jep.2014.04.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 03/17/2014] [Accepted: 04/07/2014] [Indexed: 06/03/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Premna odorata Blanco (Lamiaceae) is a medicinal plant traditionally used in Albay Province, in southeastern Luzon, Philippines to treat tuberculosis. This study aimed to determine the antitubercular property of the crude extract and sub-extracts of the leaves, and to isolate the bioactive principles from the active fractions. MATERIALS AND METHODS Through extraction, solvent polarity-based fractionation and silica gel chromatography purification of the DCM sub-extract, compound mixtures from the bioactive fractions were isolated and screened for their in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv using the colorimetric Microplate Alamar Blue assay (MABA). RESULTS The crude methanolic extract and sub-extracts showed poor inhibitory activity against Mycobacterium tuberculosis H37Rv (MIC≥128µg/mL). However, increased inhibitory potency was observed for fractions eluted from the DCM sub-extract (MIC=54 to 120µg/mL). Further purification of the most active fraction (MIC=54µg/mL) led to the isolation of a 1-heneicosyl formate (1), 4:1 mixture of β-sitosterol (2), stigmasterol (3) and diosmetin (4), which were identified through GC-MS analysis (with dereplication) and NMR experiments. The MIC of compound 1 was 8µg/mL. CONCLUSIONS The results of this study provide scientific basis for the traditional use of Premna odorata as treatment for tuberculosis.
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Affiliation(s)
- Stephen B Lirio
- Graduate School, University of Santo Tomas, España, Manila 1015, Philippines
| | - Allan Patrick G Macabeo
- Graduate School, University of Santo Tomas, España, Manila 1015, Philippines; Phytochemistry Laboratory, Research Center for the Natural and Applied Sciences, Thomas Aquinas Research Complex, University of Santo Tomas, España, Manila 1015, Philippines
| | - Erickson M Paragas
- Phytochemistry Laboratory, Research Center for the Natural and Applied Sciences, Thomas Aquinas Research Complex, University of Santo Tomas, España, Manila 1015, Philippines
| | - Matthias Knorn
- Institut fur Organische Chemie, Universitat Regensburg, Universitatsstrasse 31, 93053 Regensburg, Germany
| | - Paul Kohls
- Institut fur Organische Chemie, Universitat Regensburg, Universitatsstrasse 31, 93053 Regensburg, Germany
| | - Scott G Franzblau
- Institute for Tuberculosis Research, College of Pharmacy, University of Illinois at Chicago, 833 S. Wood Street, Chicago, IL 60612-7231, USA
| | - Yuehong Wang
- Institute for Tuberculosis Research, College of Pharmacy, University of Illinois at Chicago, 833 S. Wood Street, Chicago, IL 60612-7231, USA
| | - Ma Alicia M Aguinaldo
- Graduate School, University of Santo Tomas, España, Manila 1015, Philippines; Phytochemistry Laboratory, Research Center for the Natural and Applied Sciences, Thomas Aquinas Research Complex, University of Santo Tomas, España, Manila 1015, Philippines.
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Black PA, Warren RM, Louw GE, van Helden PD, Victor TC, Kana BD. Energy metabolism and drug efflux in Mycobacterium tuberculosis. Antimicrob Agents Chemother 2014; 58:2491-503. [PMID: 24614376 PMCID: PMC3993223 DOI: 10.1128/aac.02293-13] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The inherent drug susceptibility of microorganisms is determined by multiple factors, including growth state, the rate of drug diffusion into and out of the cell, and the intrinsic vulnerability of drug targets with regard to the corresponding antimicrobial agent. Mycobacterium tuberculosis, the causative agent of tuberculosis (TB), remains a significant source of global morbidity and mortality, further exacerbated by its ability to readily evolve drug resistance. It is well accepted that drug resistance in M. tuberculosis is driven by the acquisition of chromosomal mutations in genes encoding drug targets/promoter regions; however, a comprehensive description of the molecular mechanisms that fuel drug resistance in the clinical setting is currently lacking. In this context, there is a growing body of evidence suggesting that active extrusion of drugs from the cell is critical for drug tolerance. M. tuberculosis encodes representatives of a diverse range of multidrug transporters, many of which are dependent on the proton motive force (PMF) or the availability of ATP. This suggests that energy metabolism and ATP production through the PMF, which is established by the electron transport chain (ETC), are critical in determining the drug susceptibility of M. tuberculosis. In this review, we detail advances in the study of the mycobacterial ETC and highlight drugs that target various components of the ETC. We provide an overview of some of the efflux pumps present in M. tuberculosis and their association, if any, with drug transport and concomitant effects on drug resistance. The implications of inhibiting drug extrusion, through the use of efflux pump inhibitors, are also discussed.
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Affiliation(s)
- Philippa A. Black
- DST/NRF Centre of Excellence for Biomedical Tuberculosis Research/MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa
| | - Robin M. Warren
- DST/NRF Centre of Excellence for Biomedical Tuberculosis Research/MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa
| | - Gail E. Louw
- DST/NRF Centre of Excellence for Biomedical Tuberculosis Research/MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa
| | - Paul D. van Helden
- DST/NRF Centre of Excellence for Biomedical Tuberculosis Research/MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa
| | - Thomas C. Victor
- DST/NRF Centre of Excellence for Biomedical Tuberculosis Research/MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa
| | - Bavesh D. Kana
- DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Howard Hughes Medical Institute, Chevy Chase, Maryland, USA
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128
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Xu WX, Zhang L, Mai JT, Peng RC, Yang EZ, Peng C, Wang HH. The Wag31 protein interacts with AccA3 and coordinates cell wall lipid permeability and lipophilic drug resistance in Mycobacterium smegmatis. Biochem Biophys Res Commun 2014; 448:255-60. [PMID: 24792177 DOI: 10.1016/j.bbrc.2014.04.116] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 04/22/2014] [Indexed: 10/25/2022]
Abstract
Mycobacterium tuberculosis, especially drug resistant tuberculosis, is a serious threat to global human health. Compared with other bacterial pathogens, M. tuberculosis gains stronger natural drug resistance from its unusually lipid-rich cell wall. As a DivIVA homolog, Wag31 has been demonstrated to be closely involved in peptidoglycan synthesis, cell growth and cell division. Previous research rarely investigated the role of Wag31 in drug resistance. In this study, we found Wag31 knock-down in Mycobacterium smegmatis resulted in a co-decrease of the resistance to four lipophilic drugs (rifampicin, novobiocin, erythromycin and clofazimine) and an increase in the cell permeability to lipophilic molecules. Six proteins (AccA3, AccD4 and AccD5, Fas, InhA and MmpL3) that are involved in fatty acid and mycolic acid synthesis were identified in the Wag31 interactome through Co-Immunoprecipitation. The Wag31-AccA3 interaction was confirmed by the pull-down assay. AccA3 overexpression resulted in a decrease in lipid permeability and an increase in the resistance of rifampicin and novobiocin. It confirmed the close relationship of lipophilic drug resistance, lipid permeability and the Wag31-AccA3 interaction. These results demonstrated that Wag31 maintained the resistance to lipophilic drugs and that Wag31 could play a role in controlling the lipid permeability of the cell wall through the Wag31-AccA3 interaction.
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Affiliation(s)
- Wen-xi Xu
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai, PR China.
| | - Lu Zhang
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai, PR China.
| | - Jun-tao Mai
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai, PR China.
| | - Ru-chao Peng
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai, PR China.
| | - En-zhuo Yang
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai, PR China.
| | - Chao Peng
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai, PR China.
| | - Hong-hai Wang
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai, PR China.
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129
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de Carvalho CCCR, Costa SS, Fernandes P, Couto I, Viveiros M. Membrane transport systems and the biodegradation potential and pathogenicity of genus Rhodococcus. Front Physiol 2014; 5:133. [PMID: 24772091 PMCID: PMC3983516 DOI: 10.3389/fphys.2014.00133] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 03/18/2014] [Indexed: 11/13/2022] Open
Abstract
The Rhodococcus genus contains species with remarkable ability to tolerate toxic compounds and to degrade a myriad of substrates. These substrates have to cross a distinctive cell envelope dominated by mycolic acids anchored in a scaffold of arabinogalactan covalently attached to the cell wall peptidoglycan, and a cellular membrane with phospholipids, whose composition in fatty acids can be rapidly altered in response to environmental conditions. The hydrophobic nature of the cell envelope facilitates the entrance of hydrophobic molecules but some substrates require active transport systems. Additionally, toxic compounds may also be extruded by energy spending efflux systems. In this review, physiological evidences of the use of transport systems by Rhodococcus strains and genomic studies that corroborate their existence are presented and discussed. The recently released complete genomes of several Rhodococcus strains will be the basis for an in silico correlation analysis between the efflux pumps present in the genome and their role on active transport of substrates. These transport systems will be placed on an integrative perspective of the impact of this important genus on biotechnology and health, ranging from bioremediation to antibiotic and biocide resistance.
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Affiliation(s)
- Carla C C R de Carvalho
- Department of Bioengineering, Centre for Biological and Chemical Engineering, Institute of Biotechnology and Bioengineering, Instituto Superior Técnico, Universidade de Lisboa Lisboa, Portugal
| | - Sofia S Costa
- Grupo de Micobactérias, Unidade de Microbiologia Médica, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa Lisboa, Portugal ; Centro de Recursos Microbiológicos, Universidade Nova de Lisboa Caparica, Portugal
| | - Pedro Fernandes
- Department of Bioengineering, Centre for Biological and Chemical Engineering, Institute of Biotechnology and Bioengineering, Instituto Superior Técnico, Universidade de Lisboa Lisboa, Portugal
| | - Isabel Couto
- Grupo de Micobactérias, Unidade de Microbiologia Médica, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa Lisboa, Portugal ; Centro de Recursos Microbiológicos, Universidade Nova de Lisboa Caparica, Portugal
| | - Miguel Viveiros
- Grupo de Micobactérias, Unidade de Microbiologia Médica, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa Lisboa, Portugal ; Centro de Malária e Outras Doenças Tropicais, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa Lisboa, Portugal
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130
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Nallangi R, Samala G, Sridevi JP, Yogeeswari P, Sriram D. Development of antimycobacterial tetrahydrothieno[2,3-c]pyridine-3-carboxamides and hexahydrocycloocta[b]thiophene-3-carboxamides: Molecular modification from known antimycobacterial lead. Eur J Med Chem 2014; 76:110-7. [DOI: 10.1016/j.ejmech.2014.02.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 01/29/2014] [Accepted: 02/08/2014] [Indexed: 11/30/2022]
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131
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Insights into the bonding pattern for characterizing the open and closed state of the substrate-binding loop in Mycobacterium tuberculosis InhA. Future Med Chem 2014; 6:605-16. [DOI: 10.4155/fmc.14.27] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Background: Direct InhA inhibitors, which interact with the substrate-binding loop (SBL) and order it into a closed state, are thought to be potential anti-multidrug-resistant tuberculosis molecules. Thus, developing parameters to distinguish between the open and closed state of SBL can help in screening the potent inhibitors with loop ordering properties. Results: We report empirical parameters to differentiate the 'open' and 'closed' conformation of SBL by comprehensive analysis of InhA crystal structures. The 'open' state of SBL was observed with intra- and inter-loop H-bonding within the residues pair, G205–G208 and L207–I105, respectively, while the 'closed' conformation is found with H-bonding within the residues pair: L207–E210 and A206–I105. Moreover, potent inhibitors (IC50, 5.3–5160 nM) are observed to make hydrophobic interactions with residues of SBL, particularly with A198 in the structures with closed state of SBL. Conclusion: The observed set of H-bonding pattern and hydrophobic contact with residues of SBL can be utilized as a filter to evaluate novel inhibitors for their SBL ordering properties and potencies using the molecular dynamic simulation in the virtual screening of direct InhA inhibitors.
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132
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Lu J, Liu M, Wang Y, Pang Y, Zhao Z. Mechanisms of fluoroquinolone monoresistance inMycobacterium tuberculosis. FEMS Microbiol Lett 2014; 353:40-8. [DOI: 10.1111/1574-6968.12401] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Affiliation(s)
- Jie Lu
- Beijing Key Laboratory for Pediatric Diseases of Otolaryngology, Head and Neck Surgery; Beijing Pediatric Research Institute; Beijing Children's Hospital affiliated to Capital Medical University; Beijing China
- National Center for Tuberculosis Control and Prevention; Chinese Center for Disease Control and Prevention; Beijing China
| | - Min Liu
- Liaoning Provincial Center for Disease Control and Prevention; Shenyang China
| | - Yufeng Wang
- Beijing Key Laboratory for Pediatric Diseases of Otolaryngology, Head and Neck Surgery; Beijing Pediatric Research Institute; Beijing Children's Hospital affiliated to Capital Medical University; Beijing China
| | - Yu Pang
- National Center for Tuberculosis Control and Prevention; Chinese Center for Disease Control and Prevention; Beijing China
| | - Zhuo Zhao
- Liaoning Provincial Center for Disease Control and Prevention; Shenyang China
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133
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Antimicrobial treatment improves mycobacterial survival in nonpermissive growth conditions. Antimicrob Agents Chemother 2014; 58:2798-806. [PMID: 24590482 PMCID: PMC3993263 DOI: 10.1128/aac.02774-13] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Antimicrobials targeting cell wall biosynthesis are generally considered inactive against nonreplicating bacteria. Paradoxically, we found that under nonpermissive growth conditions, exposure of Mycobacterium bovis BCG bacilli to such antimicrobials enhanced their survival. We identified a transcriptional regulator, RaaS (for regulator of antimicrobial-assisted survival), encoded by bcg1279 (rv1219c) as being responsible for the observed phenomenon. Induction of this transcriptional regulator resulted in reduced expression of specific ATP-dependent efflux pumps and promoted long-term survival of mycobacteria, while its deletion accelerated bacterial death under nonpermissive growth conditions in vitro and during macrophage or mouse infection. These findings have implications for the design of antimicrobial drug combination therapies for persistent infectious diseases, such as tuberculosis.
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134
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Viveiros M, Martins M, Couto I, Rodrigues L, Machado D, Portugal I, Amaral L. Molecular tools for rapid identification and novel effective therapy against MDRTB/XDRTB infections. Expert Rev Anti Infect Ther 2014; 8:465-80. [DOI: 10.1586/eri.10.20] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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135
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Viveiros M, Martins M, Rodrigues L, Machado D, Couto I, Ainsa J, Amaral L. Inhibitors of mycobacterial efflux pumps as potential boosters for anti-tubercular drugs. Expert Rev Anti Infect Ther 2014; 10:983-98. [DOI: 10.1586/eri.12.89] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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136
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Belardinelli JM, Morbidoni HR. Recycling and refurbishing old antitubercular drugs: the encouraging case of inhibitors of mycolic acid biosynthesis. Expert Rev Anti Infect Ther 2014; 11:429-40. [DOI: 10.1586/eri.13.24] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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137
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Gupta S, Tyagi S, Almeida DV, Maiga MC, Ammerman NC, Bishai WR. Acceleration of tuberculosis treatment by adjunctive therapy with verapamil as an efflux inhibitor. Am J Respir Crit Care Med 2013; 188:600-7. [PMID: 23805786 DOI: 10.1164/rccm.201304-0650oc] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
RATIONALE A major priority in tuberculosis (TB) is to reduce effective treatment times and emergence of resistance. Recent studies in macrophages and zebrafish show that inhibition of mycobacterial efflux pumps with verapamil reduces the bacterial drug tolerance and may enhance drug efficacy. OBJECTIVES Using mice, a mammalian model known to predict human treatment responses, and selecting conservative human bioequivalent doses, we tested verapamil as an adjunctive drug together with standard TB chemotherapy. As verapamil is a substrate for CYP3A4, which is induced by rifampin, we evaluated the pharmacokinetic/pharmacodynamic relationships of verapamil and rifampin coadministration in mice. METHODS Using doses that achieve human bioequivalent levels matched to those of standard verapamil, but lower than those of extended release verapamil, we evaluated the activity of verapamil added to standard chemotherapy in both C3HeB/FeJ (which produce necrotic granulomas) and the wild-type background C3H/HeJ mouse strains. Relapse rates were assessed after 16, 20, and 24 weeks of treatment in mice. MEASUREMENTS AND MAIN RESULTS We determined that a dose adjustment of verapamil by 1.5-fold is required to compensate for concurrent use of rifampin during TB treatment. We found that standard TB chemotherapy plus verapamil accelerates bacterial clearance in C3HeB/FeJ mice with near sterilization, and significantly lowers relapse rates in just 4 months of treatment when compared with mice receiving standard therapy alone. CONCLUSIONS These data demonstrate treatment shortening by verapamil adjunctive therapy in mice, and strongly support further study of verapamil and other efflux pump inhibitors in human TB.
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Affiliation(s)
- Shashank Gupta
- Center for Tuberculosis Research, Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
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138
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Malkhed V, Mustyala KK, Potlapally SR, Vuruputuri U. Identification of novel leads applyingin silicostudies for Mycobacterium multidrug resistant (MMR) protein. J Biomol Struct Dyn 2013; 32:1889-906. [DOI: 10.1080/07391102.2013.842185] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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139
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140
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Roy SK, Kumari N, Gupta S, Pahwa S, Nandanwar H, Jachak SM. 7-Hydroxy-(E)-3-phenylmethylene-chroman-4-one analogues as efflux pump inhibitors against Mycobacterium smegmatis mc² 155. Eur J Med Chem 2013; 66:499-507. [PMID: 23832254 DOI: 10.1016/j.ejmech.2013.06.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 03/21/2013] [Accepted: 06/03/2013] [Indexed: 11/28/2022]
Abstract
Efflux pump (EP) induces resistance in mycobacteria and hence could be explored as a new target for the discovery of anti-TB agents. In search for efflux pump inhibitors from natural products, bonducellin, a homoisoflavonoid was isolated from Caesalpinia digyna roots and evaluated for modulation and EP inhibitory activity. Bonducellin showed modulation in the MIC of EtBr by eight fold at a concentration of 62.5 mg/L and also showed significant EP inhibitory activity. A synthetic scheme was designed to prepare analogues of 7-hydroxy-(E)-3-phenylmethylene-chroman-4-one by modification at the phenylmethylene-ring and the synthesized compounds were evaluated in accumulation and efflux assays. Analogues 1, 7-11, 13-15, 17 and 19 were found to be good modulators and decreased the MIC of EtBr by ≥4 fold at sub-inhibitory concentration. The compounds 8, 13 and 17 were the most potent inhibitors of ethidium bromide efflux in Mycobacterium smegmatis mc(2) 155.
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Affiliation(s)
- Somendu K Roy
- Department of Natural Products, National Institute of Pharmaceutical Education and Research, Sector-67, SAS Nagar, Mohali 160062, Punjab, India
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141
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Sarathy JP, Lee E, Dartois V. Polyamines inhibit porin-mediated fluoroquinolone uptake in mycobacteria. PLoS One 2013; 8:e65806. [PMID: 23755283 PMCID: PMC3670895 DOI: 10.1371/journal.pone.0065806] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2013] [Accepted: 04/28/2013] [Indexed: 11/19/2022] Open
Abstract
Polyamines decrease the permeability of the outer membrane of Escherichia coli to fluoroquinolones and β-lactams. In this study, we tested the effect of four polyamines (spermidine, spermine, cadaverine and putrescine) on fluoroquinolone uptake in Mycobacterium bovis BCG. Our results show that polyamines are also capable of reducing the permeability of the mycobacterial outer membrane to fluoroquinolones. Spermidine was most effective and demonstrated reversible dose- and pH-dependent inhibition of ciprofloxacin accumulation. The extent of this inhibition was demonstrated across the fluoroquinolone compound class to varying degrees. Furthermore, we have shown that the addition of spermidine increases the survival of M. bovis BCG after a 5-day exposure to ciprofloxacin by up to 25 times. The treatment of actively-replicating Mycobacterium tuberculosis with spermidine reduced ciprofloxacin accumulation by half while non-replicating nutrient-starved M. tuberculosis cultures lacked similar sensitivity to polyamines. Gene expression studies showed that several outer membrane proteins are significantly down-regulated during the shift to non-replication. Collectively, these characteristics of fluoroquinolone uptake in M. bovis BCG are consistent with facilitated transport by porin-like proteins and suggest that a reduction in intracellular uptake contributes to the phenotypic drug resistance demonstrated by M. tuberculosis in the non-replicating state.
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142
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Calgin MK, Sahin F, Turegun B, Gerceker D, Atasever M, Koksal D, Karasartova D, Kiyan M. Expression analysis of efflux pump genes among drug-susceptible and multidrug-resistant Mycobacterium tuberculosis clinical isolates and reference strains. Diagn Microbiol Infect Dis 2013; 76:291-7. [PMID: 23561272 DOI: 10.1016/j.diagmicrobio.2013.02.033] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 02/08/2013] [Accepted: 02/27/2013] [Indexed: 11/28/2022]
Abstract
Finding a gene or genes that are involved with multidrug resistance will be useful for finding a new target for the treatment of drug resistant tuberculosis. In this study, we aimed to compare the differences of the expression of 15 putative multidrug efflux pump genes in clinically isolated drug sensitive and multidrug resistant (MDR) Mycobacterium tuberculosis isolates, and reference strains. We found that these genes in the drug-sensitive and MDR M. tuberculosis isolates have similar rates of expressions. However, we found the expression levels of the all the genes are significantly higher in the clinical strains compared to the expression level of genes in the reference strains. In addition to this, it is found that standard strain has lower MIC value for the drugs including streptomycin and rifampin compared to the clinical isolate. We presume that the increase of the gene expression in the clinical strains is due to the exposure of antituberculosis drugs during treatment of patients, which cause constitutive expression of efflux systems, which might increase MIC levels of the major anti-tuberculosis drugs.
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Affiliation(s)
- Mustafa Kerem Calgin
- Microbiology Department, Faculty of Medicine, Ankara University, 06100 Sihhiye-Ankara, Turkey
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143
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Luo X, Pires D, Aínsa JA, Gracia B, Duarte N, Mulhovo S, Anes E, Ferreira MJU. Zanthoxylum capense constituents with antimycobacterial activity against Mycobacterium tuberculosis in vitro and ex vivo within human macrophages. JOURNAL OF ETHNOPHARMACOLOGY 2013; 146:417-422. [PMID: 23337743 DOI: 10.1016/j.jep.2013.01.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 11/29/2012] [Accepted: 01/09/2013] [Indexed: 06/01/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Zanthoxylum capense Thunb. (Rutaceae) is a medicinal plant traditionally used in Mozambique to treat tuberculosis. AIMS OF THE STUDY The main aim of the study was to find antimycobacterial lead compounds from Zanthoxylum capense. Another goal was to provide scientific validation for the use of this plant in traditional medicine. METHODS AND MATERIALS By bioassay-guided fractionation, 16 compounds were isolated and screened for their in vitro antimycobacterial activity against two different strains of Mycobacterium tuberculosis. Their in vitro cytotoxicity to human THP-1 macrophages was also assessed. The compounds with favourable selectivity index values (SI>10) were further investigated for their ability to inhibit the growth of Mycobacterium tuberculosis H37Rv in an intracellular macrophage model of infection. RESULTS The best results were obtained for a benzophenanthridine alkaloid, decarine (1), and an N-isobutylamide, N-isobutyl-(2E,4E)-2,4-tetradecadienamide (15), which showed high activity against Mycobacterium tuberculosis H37Rv (MIC of 1.6 μg/ml), and a low macrophage cytotoxicity (IC50>60 μg/ml), indicating considerable selective activity. The benzophenanthridine alkaloid 6-acetonyldihydronitidine (6) revealed cytotoxicity (IC50 1.7 μg/ml), despite the determined MIC of 6.2-12.5 μg/ml. In infected macrophages, decarine (1) was able to reduce bacterial survival by almost two log units at a concentration of 6.2 μg/ml 5 days post-drug exposure. Compound 15 exhibited an intermediate activity at drug concentrations ranging from 6.2 to 25 μg/ml. CONCLUSIONS The high antimycobacterial activity of decarine found, both in vitro and ex vivo against mycobacteria, and the low cytotoxicity towards human macrophages indicate that it may be valuable as a lead scaffold for the development of anti-TB drugs.
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Affiliation(s)
- Xuan Luo
- Research Institute for Medicines and Pharmaceutical Sciences (iMed.UL), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
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144
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Amaral L, Molnar J. Why and how thioridazine in combination with antibiotics to which the infective strain is resistant will cure totally drug-resistant tuberculosis. Expert Rev Anti Infect Ther 2013; 10:869-73. [PMID: 23030326 DOI: 10.1586/eri.12.73] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Over a period of 14 years, the authors have studied thioridazine, an old neuroleptic, that has been shown to have in vitro activity against intracellular Mycobacterium tuberculosis, regardless of its antibiotic resistance status, thioridazine cures infected mice of antibiotic-susceptible and multidrug-resistant tuberculosis (TB) infections and, when used in combination with antibiotics used for therapy of TB, renders the organism significantly more susceptible. This article will describe the authors' further work and the mechanisms by which thioridazine alone and in combination with antibiotics cures an extensively drug-resistant infection and why it is expected to cure totally drug-resistant TB infections as well. The concepts presented are entirely new and because they focus on the activation of killing by nonkilling macrophages where M. tuberculosis normally resides during infection, and coupled to the inhibition of efflux pumps which contribute to the antibiotic-resistant status, effective therapy of any antibiotic-resistant TB infection is possible.
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Affiliation(s)
- Leonard Amaral
- Institute of Hygiene and Tropical Medicine, Universidade Nova de Lisboa, Rua Junqueira 100, 1349-008 Lisbon, Portugal.
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145
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Alvarez-Ortega C, Olivares J, Martínez JL. RND multidrug efflux pumps: what are they good for? Front Microbiol 2013; 4:7. [PMID: 23386844 PMCID: PMC3564043 DOI: 10.3389/fmicb.2013.00007] [Citation(s) in RCA: 135] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Accepted: 01/07/2013] [Indexed: 01/27/2023] Open
Abstract
Multidrug efflux pumps are chromosomally encoded genetic elements capable of mediating resistance to toxic compounds in several life forms. In bacteria, these elements are involved in intrinsic and acquired resistance to antibiotics. Unlike other well-known horizontally acquired antibiotic resistance determinants, genes encoding for multidrug efflux pumps belong to the core of bacterial genomes and thus have evolved over millions of years. The selective pressure stemming from the use of antibiotics to treat bacterial infections is relatively recent in evolutionary terms. Therefore, it is unlikely that these elements have evolved in response to antibiotics. In the last years, several studies have identified numerous functions for efflux pumps that go beyond antibiotic extrusion. In this review we present some examples of these functions that range from bacterial interactions with plant or animal hosts, to the detoxification of metabolic intermediates or the maintenance of cellular homeostasis.
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Affiliation(s)
- Carolina Alvarez-Ortega
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas Madrid, Spain
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Involvement of efflux pumps in the resistance to peptidoglycan synthesis inhibitors in Mycobacterium tuberculosis. Antimicrob Agents Chemother 2013; 57:1941-3. [PMID: 23335736 DOI: 10.1128/aac.01957-12] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We evaluated the contributions of Mycobacterium tuberculosis efflux pumps towards intrinsic resistance to different classes of peptidoglycan synthesis inhibitors (PSI). Our study indicates that the efflux pump knockout strains are more susceptible to PSI than the wild type. Vancomycin and ceftriaxone exhibited up to 3 log increased kill on efflux pump mutants compared to the wild-type strain, strongly suggesting an important role for efflux pumps in the intrinsic resistance of M. tuberculosis to PSI.
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Characterization of the MSMEG_2631 gene (mmp) encoding a multidrug and toxic compound extrusion (MATE) family protein in Mycobacterium smegmatis and exploration of its polyspecific nature using biolog phenotype microarray. J Bacteriol 2013; 195:1610-21. [PMID: 23292779 DOI: 10.1128/jb.01724-12] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In Mycobacterium, multidrug efflux pumps can be associated with intrinsic drug resistance. Comparison of putative mycobacterial transport genes revealed a single annotated open reading frame (ORF) for a multidrug and toxic compound extrusion (MATE) family efflux pump in all sequenced mycobacteria except Mycobacterium leprae. Since MATE efflux pumps function as multidrug efflux pumps by conferring resistance to structurally diverse antibiotics and DNA-damaging chemicals, we studied this gene (MSMEG_2631) in M. smegmatis mc(2)155 and determined that it encodes a MATE efflux system that contributes to intrinsic resistance of Mycobacterium. We propose that the MSMEG_2631 gene be named mmp, for mycobacterial MATE protein. Biolog Phenotype MicroArray data indicated that mmp deletion increased susceptibility for phleomycin, bleomycin, capreomycin, amikacin, kanamycin, cetylpyridinium chloride, and several sulfa drugs. MSMEG_2619 (efpA) and MSMEG_3563 mask the effect of mmp deletion due to overlapping efflux capabilities. We present evidence that mmp is a part of an MSMEG_2626-2628-2629-2630-2631 operon regulated by a strong constitutive promoter, initiated from a single transcription start site. All together, our results show that M. smegmatis constitutively encodes an Na(+)-dependent MATE multidrug efflux pump from mmp in an operon with putative genes encoding proteins for apparently unrelated functions.
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148
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Role of the Mmr efflux pump in drug resistance in Mycobacterium tuberculosis. Antimicrob Agents Chemother 2012; 57:751-7. [PMID: 23165464 DOI: 10.1128/aac.01482-12] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Efflux pumps are membrane proteins capable of actively transporting a broad range of substrates from the cytoplasm to the exterior of the cell. Increased efflux activity in response to drug treatment may be the first step in the development of bacterial drug resistance. Previous studies showed that the efflux pump Mmr was significantly overexpressed in strains exposed to isoniazid. In the work to be described, we constructed mutants lacking or overexpressing Mmr in order to clarify the role of this efflux pump in the development of resistance to isoniazid and other drugs in M. tuberculosis. The mmr knockout mutant showed an increased susceptibility to ethidium bromide, tetraphenylphosphonium, and cetyltrimethylammonium bromide (CTAB). Overexpression of mmr caused a decreased susceptibility to ethidium bromide, acriflavine, and safranin O that was obliterated in the presence of the efflux inhibitors verapamil and carbonyl cyanide m-chlorophenylhydrazone. Isoniazid susceptibility was not affected by the absence or overexpression of mmr. The fluorometric method allowed the detection of a decreased efflux of ethidium bromide in the knockout mutant, whereas the overexpressed strain showed increased efflux of this dye. This increased efflux activity was inhibited in the presence of efflux inhibitors. Under our experimental conditions, we have found that efflux pump Mmr is mainly involved in the susceptibility to quaternary compounds such as ethidium bromide and disinfectants such as CTAB. The contribution of this efflux pump to isoniazid resistance in Mycobacterium tuberculosis still needs to be further elucidated.
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Sarathy JP, Dartois V, Lee EJD. The role of transport mechanisms in mycobacterium tuberculosis drug resistance and tolerance. Pharmaceuticals (Basel) 2012; 5:1210-35. [PMID: 24281307 PMCID: PMC3816664 DOI: 10.3390/ph5111210] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 10/25/2012] [Accepted: 11/02/2012] [Indexed: 02/02/2023] Open
Abstract
In the fight against tuberculosis, cell wall permeation of chemotherapeutic agents remains a critical but largely unsolved question. Here we review the major mechanisms of small molecule penetration into and efflux from Mycobacterium tuberculosis and other mycobacteria, and outline how these mechanisms may contribute to the development of phenotypic drug tolerance and induction of drug resistance. M. tuberculosis is intrinsically recalcitrant to small molecule permeation thanks to its thick lipid-rich cell wall. Passive diffusion appears to account for only a fraction of total drug permeation. As in other bacterial species, influx of hydrophilic compounds is facilitated by water-filled open channels, or porins, spanning the cell wall. However, the diversity and density of M. tuberculosis porins appears lower than in enterobacteria. Besides, physiological adaptations brought about by unfavorable conditions are thought to reduce the efficacy of porins. While intracellular accumulation of selected drug classes supports the existence of hypothesized active drug influx transporters, efflux pumps contribute to the drug resistant phenotype through their natural abundance and diversity, as well as their highly inducible expression. Modulation of efflux transporter expression has been observed in phagocytosed, non-replicating persistent and multi-drug resistant bacilli. Altogether, M. tuberculosis has evolved both intrinsic properties and acquired mechanisms to increase its level of tolerance towards xenobiotic substances, by preventing or minimizing their entry. Understanding these adaptation mechanisms is critical to counteract the natural mechanisms of defense against toxic compounds and develop new classes of chemotherapeutic agents that positively exploit the influx and efflux pathways of mycobacteria.
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Affiliation(s)
- Jansy Passiflora Sarathy
- Novartis Institute for Tropical Diseases Pte Ltd, 10 Biopolis Road #05-01, Chromos, 138670, Singapore.
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Kurinčič M, Klančnik A, Smole Možina S. Epigallocatechin gallate as a modulator of Campylobacter resistance to macrolide antibiotics. Int J Antimicrob Agents 2012; 40:467-71. [DOI: 10.1016/j.ijantimicag.2012.07.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 06/18/2012] [Accepted: 07/20/2012] [Indexed: 12/11/2022]
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