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Te Brake LHM, de Knegt GJ, de Steenwinkel JE, van Dam TJP, Burger DM, Russel FGM, van Crevel R, Koenderink JB, Aarnoutse RE. The Role of Efflux Pumps in Tuberculosis Treatment and Their Promise as a Target in Drug Development: Unraveling the Black Box. Annu Rev Pharmacol Toxicol 2017; 58:271-291. [PMID: 28715978 DOI: 10.1146/annurev-pharmtox-010617-052438] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Insight into drug transport mechanisms is highly relevant to the efficacious treatment of tuberculosis (TB). Major problems in TB treatment are related to the transport of antituberculosis (anti-TB) drugs across human and mycobacterial membranes, affecting the concentrations of these drugs systemically and locally. Firstly, transporters located in the intestines, liver, and kidneys all determine the pharmacokinetics and pharmacodynamics of anti-TB drugs, with a high risk of drug-drug interactions in the setting of concurrent use of antimycobacterial, antiretroviral, and antidiabetic agents. Secondly, human efflux transporters limit the penetration of anti-TB drugs into the brain and cerebrospinal fluid, which is especially important in the treatment of TB meningitis. Finally, efflux transporters located in the macrophage and Mycobacterium tuberculosis cell membranes play a pivotal role in the emergence of phenotypic tolerance and drug resistance, respectively. We review the role of efflux transporters in TB drug disposition and evaluate the promise of efflux pump inhibition from a novel holistic perspective.
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Affiliation(s)
- Lindsey H M Te Brake
- Department of Pharmacy, Radboud Institute for Health Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands; .,Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Gerjo J de Knegt
- Department of Medical Microbiology and Infectious Diseases, Erasmus Medical Center, 3015 CN Rotterdam, The Netherlands
| | - Jurriaan E de Steenwinkel
- Department of Medical Microbiology and Infectious Diseases, Erasmus Medical Center, 3015 CN Rotterdam, The Netherlands
| | - Teunis J P van Dam
- Centre for Molecular and Biomolecular Informatics, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - David M Burger
- Department of Pharmacy, Radboud Institute for Health Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands;
| | - Frans G M Russel
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Reinout van Crevel
- Department of Internal Medicine, Radboud Institute for Health Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Jan B Koenderink
- Department of Pharmacology and Toxicology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Rob E Aarnoutse
- Department of Pharmacy, Radboud Institute for Health Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands;
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The importance of clinical pharmacokinetic-pharmacodynamic studies in unraveling the determinants of early and late tuberculosis outcomes. ACTA ACUST UNITED AC 2017; 2:195-212. [PMID: 30283633 PMCID: PMC6161803 DOI: 10.4155/ipk-2017-0004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 05/16/2017] [Indexed: 12/17/2022]
Abstract
Tuberculosis remains a major infectious cause of morbidity and mortality worldwide. Current antibiotic regimens, constructed prior to the development of modern pharmacokinetic-pharmacodynamic (PK–PD) tools, are based on incomplete understanding of exposure–response relationships in drug susceptible and multidrug resistant tuberculosis. Preclinical and population PK data suggest that clinical PK–PD studies may enable therapeutic drug monitoring for some agents and revised dosing for others. Future clinical PK–PD challenges include: incorporation of PK methods to assay free concentrations for all active metabolites; selection of appropriate early outcome measures which reflect therapeutic response; elucidation of genetic contributors to interindividual PK variability; conduct of targeted studies on special populations (including children); and measurement of PK–PD parameters at the site of disease.
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Efflux Attenuates the Antibacterial Activity of Q203 in Mycobacterium tuberculosis. Antimicrob Agents Chemother 2017; 61:AAC.02637-16. [PMID: 28416541 DOI: 10.1128/aac.02637-16] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 03/31/2017] [Indexed: 11/20/2022] Open
Abstract
New and improved treatments for tuberculosis (TB) are urgently needed. Recently, it has been demonstrated that verapamil, an efflux inhibitor, can reduce bacterial drug tolerance caused by efflux pump activity when administered in combination with available antituberculosis agents. The aim of this study was to evaluate the effectiveness of verapamil in combination with the antituberculosis drug candidate Q203, which has recently been developed and is currently under clinical trials as a potential antituberculosis agent. We evaluated changes in Q203 activity in the presence and absence of verapamil in vitro using the resazurin microplate assay and ex vivo using a microscopy-based phenotypic assay for the quantification of intracellular replicating mycobacteria. Verapamil increased the potency of Q203 against Mycobacterium tuberculosis both in vitro and ex vivo, indicating that efflux pumps are associated with the activity of Q203. Other efflux pump inhibitors also displayed an increase in Q203 potency, strengthening this hypothesis. Therefore, the combination of verapamil and Q203 may be a promising combinatorial strategy for anti-TB treatment to accelerate the elimination of M. tuberculosis.
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54
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Dheda K, Gumbo T, Maartens G, Dooley KE, McNerney R, Murray M, Furin J, Nardell EA, London L, Lessem E, Theron G, van Helden P, Niemann S, Merker M, Dowdy D, Van Rie A, Siu GKH, Pasipanodya JG, Rodrigues C, Clark TG, Sirgel FA, Esmail A, Lin HH, Atre SR, Schaaf HS, Chang KC, Lange C, Nahid P, Udwadia ZF, Horsburgh CR, Churchyard GJ, Menzies D, Hesseling AC, Nuermberger E, McIlleron H, Fennelly KP, Goemaere E, Jaramillo E, Low M, Jara CM, Padayatchi N, Warren RM. The epidemiology, pathogenesis, transmission, diagnosis, and management of multidrug-resistant, extensively drug-resistant, and incurable tuberculosis. THE LANCET. RESPIRATORY MEDICINE 2017; 5:S2213-2600(17)30079-6. [PMID: 28344011 DOI: 10.1016/s2213-2600(17)30079-6] [Citation(s) in RCA: 382] [Impact Index Per Article: 54.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 10/24/2016] [Accepted: 12/08/2016] [Indexed: 12/25/2022]
Abstract
Global tuberculosis incidence has declined marginally over the past decade, and tuberculosis remains out of control in several parts of the world including Africa and Asia. Although tuberculosis control has been effective in some regions of the world, these gains are threatened by the increasing burden of multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis. XDR tuberculosis has evolved in several tuberculosis-endemic countries to drug-incurable or programmatically incurable tuberculosis (totally drug-resistant tuberculosis). This poses several challenges similar to those encountered in the pre-chemotherapy era, including the inability to cure tuberculosis, high mortality, and the need for alternative methods to prevent disease transmission. This phenomenon mirrors the worldwide increase in antimicrobial resistance and the emergence of other MDR pathogens, such as malaria, HIV, and Gram-negative bacteria. MDR and XDR tuberculosis are associated with high morbidity and substantial mortality, are a threat to health-care workers, prohibitively expensive to treat, and are therefore a serious public health problem. In this Commission, we examine several aspects of drug-resistant tuberculosis. The traditional view that acquired resistance to antituberculous drugs is driven by poor compliance and programmatic failure is now being questioned, and several lines of evidence suggest that alternative mechanisms-including pharmacokinetic variability, induction of efflux pumps that transport the drug out of cells, and suboptimal drug penetration into tuberculosis lesions-are likely crucial to the pathogenesis of drug-resistant tuberculosis. These factors have implications for the design of new interventions, drug delivery and dosing mechanisms, and public health policy. We discuss epidemiology and transmission dynamics, including new insights into the fundamental biology of transmission, and we review the utility of newer diagnostic tools, including molecular tests and next-generation whole-genome sequencing, and their potential for clinical effectiveness. Relevant research priorities are highlighted, including optimal medical and surgical management, the role of newer and repurposed drugs (including bedaquiline, delamanid, and linezolid), pharmacokinetic and pharmacodynamic considerations, preventive strategies (such as prophylaxis in MDR and XDR contacts), palliative and patient-orientated care aspects, and medicolegal and ethical issues.
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Affiliation(s)
- Keertan Dheda
- Lung Infection and Immunity Unit, Department of Medicine, Division of Pulmonology and UCT Lung Institute, University of Cape Town, Groote Schuur Hospital, Cape Town, South Africa.
| | - Tawanda Gumbo
- Center for Infectious Diseases Research and Experimental Therapeutics, Baylor Research Institute, Baylor University Medical Center, Dallas, TX, USA
| | - Gary Maartens
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Kelly E Dooley
- Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ruth McNerney
- Lung Infection and Immunity Unit, Department of Medicine, Division of Pulmonology and UCT Lung Institute, University of Cape Town, Groote Schuur Hospital, Cape Town, South Africa
| | - Megan Murray
- Department of Global Health and Social Medicine, Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Jennifer Furin
- Department of Global Health and Social Medicine, Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Edward A Nardell
- TH Chan School of Public Health, Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Leslie London
- School of Public Health and Medicine, University of Cape Town, Cape Town, South Africa
| | | | - Grant Theron
- SA MRC Centre for Tuberculosis Research/DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, Division of Molecular Biology and Human Genetics, Stellenbosch University, Tygerberg, South Africa
| | - Paul van Helden
- SA MRC Centre for Tuberculosis Research/DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, Division of Molecular Biology and Human Genetics, Stellenbosch University, Tygerberg, South Africa
| | - Stefan Niemann
- Molecular and Experimental Mycobacteriology, Research Center Borstel, Borstel, Schleswig-Holstein, Germany; German Centre for Infection Research (DZIF), Partner Site Borstel, Borstel, Schleswig-Holstein, Germany
| | - Matthias Merker
- Molecular and Experimental Mycobacteriology, Research Center Borstel, Borstel, Schleswig-Holstein, Germany
| | - David Dowdy
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Annelies Van Rie
- University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; International Health Unit, Epidemiology and Social Medicine, Faculty of Medicine, University of Antwerp, Antwerp, Belgium
| | - Gilman K H Siu
- Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hung Hom, Hong Kong SAR, China
| | - Jotam G Pasipanodya
- Center for Infectious Diseases Research and Experimental Therapeutics, Baylor Research Institute, Baylor University Medical Center, Dallas, TX, USA
| | - Camilla Rodrigues
- Department of Microbiology, P.D. Hinduja National Hospital & Medical Research Centre, Mumbai, India
| | - Taane G Clark
- Faculty of Infectious and Tropical Diseases and Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK
| | - Frik A Sirgel
- SA MRC Centre for Tuberculosis Research/DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, Division of Molecular Biology and Human Genetics, Stellenbosch University, Tygerberg, South Africa
| | - Aliasgar Esmail
- Lung Infection and Immunity Unit, Department of Medicine, Division of Pulmonology and UCT Lung Institute, University of Cape Town, Groote Schuur Hospital, Cape Town, South Africa
| | - Hsien-Ho Lin
- Institute of Epidemiology and Preventive Medicine, National Taiwan University, Taipei, Taiwan
| | - Sachin R Atre
- Center for Clinical Global Health Education (CCGHE), Johns Hopkins University, Baltimore, MD, USA; Medical College, Hospital and Research Centre, Pimpri, Pune, India
| | - H Simon Schaaf
- Desmond Tutu TB Centre, Department of Paediatrics and Child Health, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Kwok Chiu Chang
- Tuberculosis and Chest Service, Centre for Health Protection, Department of Health, Hong Kong SAR, China
| | - Christoph Lange
- Division of Clinical Infectious Diseases, German Center for Infection Research, Research Center Borstel, Borstel, Schleswig-Holstein, Germany; International Health/Infectious Diseases, University of Lübeck, Lübeck, Germany; Department of Medicine, Karolinska Institute, Stockholm, Sweden; Department of Medicine, University of Namibia School of Medicine, Windhoek, Namibia
| | - Payam Nahid
- Division of Pulmonary and Critical Care, San Francisco General Hospital, University of California, San Francisco, CA, USA
| | - Zarir F Udwadia
- Pulmonary Department, Hinduja Hospital & Research Center, Mumbai, India
| | | | - Gavin J Churchyard
- Aurum Institute, Johannesburg, South Africa; School of Public Health, University of Witwatersrand, Johannesburg, South Africa; Advancing Treatment and Care for TB/HIV, South African Medical Research Council, Johannesburg, South Africa
| | - Dick Menzies
- Montreal Chest Institute, McGill University, Montreal, QC, Canada
| | - Anneke C Hesseling
- Desmond Tutu TB Centre, Department of Paediatrics and Child Health, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Eric Nuermberger
- Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Helen McIlleron
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Kevin P Fennelly
- Pulmonary Clinical Medicine Section, Division of Intramural Research, National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Eric Goemaere
- MSF South Africa, Cape Town, South Africa; School of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa
| | | | - Marcus Low
- Treatment Action Campaign, Johannesburg, South Africa
| | | | - Nesri Padayatchi
- Centre for the AIDS Programme of Research in South Africa (CAPRISA), MRC HIV-TB Pathogenesis and Treatment Research Unit, Durban, South Africa
| | - Robin M Warren
- SA MRC Centre for Tuberculosis Research/DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, Division of Molecular Biology and Human Genetics, Stellenbosch University, Tygerberg, South Africa
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Rodrigues L, Parish T, Balganesh M, Ainsa JA. Antituberculosis drugs: reducing efflux = increasing activity. Drug Discov Today 2017; 22:592-599. [DOI: 10.1016/j.drudis.2017.01.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 12/21/2016] [Accepted: 01/05/2017] [Indexed: 11/30/2022]
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Reduced Chance of Hearing Loss Associated with Therapeutic Drug Monitoring of Aminoglycosides in the Treatment of Multidrug-Resistant Tuberculosis. Antimicrob Agents Chemother 2017; 61:AAC.01400-16. [PMID: 28069654 DOI: 10.1128/aac.01400-16] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 12/04/2016] [Indexed: 11/20/2022] Open
Abstract
Hearing loss and nephrotoxicity are associated with prolonged treatment duration and higher dosage of amikacin and kanamycin. In our tuberculosis center, we used therapeutic drug monitoring (TDM) targeting preset pharmacokinetic/pharmacodynamic (PK/PD) surrogate endpoints in an attempt to maintain efficacy while preventing (oto)toxicity. To evaluate this strategy, we retrospectively evaluated medical charts of tuberculosis (TB) patients treated with amikacin or kanamycin in the period from 2000 to 2012. Patients with culture-confirmed multiresistant or extensively drug-resistant tuberculosis (MDR/XDR-TB) receiving amikacin or kanamycin as part of their TB treatment for at least 3 days were eligible for inclusion in this retrospective study. Clinical data, including maximum concentration (Cmax), Cmin, and audiometry data, were extracted from the patients' medical charts. A total of 80 patients met the inclusion criteria. The mean weighted Cmax/MIC ratios obtained from 57 patients were 31.2 for amikacin and 12.3 for kanamycin. The extent of hearing loss was limited and correlated with the cumulative drug dose per kg of body weight during daily administration. At follow-up, 35 (67.3%) of all patients had successful outcome; there were no relapses. At a median dose of 6.5 mg/kg, a correlation was found between the dose per kg of body weight during daily dosing and the extent of hearing loss in dB at 8,000 Hz. These findings suggest that the efficacy at this lower dosage is maintained with limited toxicity. A randomized controlled trial should provide final proof of the safety and efficacy of TDM-guided use of aminoglycosides in MDR-TB treatment.
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Moxifloxacin's Limited Efficacy in the Hollow-Fiber Model of Mycobacterium abscessus Disease. Antimicrob Agents Chemother 2016; 60:3779-85. [PMID: 27067317 DOI: 10.1128/aac.02821-15] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 04/03/2016] [Indexed: 01/12/2023] Open
Abstract
Current regimens used to treat pulmonary Mycobacterium abscessus disease have limited efficacy. There is an urgent need for new drugs and optimized combinations and doses. We performed hollow-fiber-system studies in which M. abscessus was exposed to moxifloxacin lung concentration-time profiles similar to human doses of between 0 and 800 mg/day. The minimum bactericidal concentration and MIC were 8 and 2 mg/liter, respectively, in our M. abscessus strain, suggesting bactericidal activity. Measurement of the moxifloxacin concentrations in each hollow-fiber system revealed an elimination rate constant (kel) of 0.11 ± 0.05 h(-1) (mean ± standard deviation) (half-life of 9.8 h). Inhibitory sigmoid maximal effect (Emax) modeling revealed that the highest Emax was 3.15 ± 1.84 log10 CFU/ml on day 3, and the exposure mediating 50% of Emax (EC50) was a 0- to 24-h area under the concentration time curve (AUC0-24)-to-MIC ratio of 41.99 ± 31.78 (r(2) = 0.99). The EC80 was an AUC0-24/MIC ratio of 102.11. However, no moxifloxacin concentration killed the bacteria to burdens below the starting inoculum. There was regrowth beyond day 3 in all doses, with replacement by a resistant subpopulation that had an MIC of >32 mg/liter by the end of the experiment. A quadratic function best described the relationship between the AUC0-24/MIC ratio and the moxifloxacin-resistant subpopulation. Monte Carlo simulations of 10,000 patients revealed that the 400- to 800-mg/day doses would achieve or exceed the EC80 in ≤12.5% of patients. The moxifloxacin susceptibility breakpoint was 0.25 mg/liter, which means that almost all M. abscessus clinical strains are moxifloxacin resistant by these criteria. While moxifloxacin's efficacy against M. abscessus was poor, formal combination therapy studies with moxifloxacin are still recommended.
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A Long-term Co-perfused Disseminated Tuberculosis-3D Liver Hollow Fiber Model for Both Drug Efficacy and Hepatotoxicity in Babies. EBioMedicine 2016; 6:126-138. [PMID: 27211555 PMCID: PMC4856747 DOI: 10.1016/j.ebiom.2016.02.040] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 02/15/2016] [Accepted: 02/25/2016] [Indexed: 11/21/2022] Open
Abstract
Treatment of disseminated tuberculosis in children ≤ 6 years has not been optimized. The pyrazinamide-containing combination regimen used to treat disseminated tuberculosis in babies and toddlers was extrapolated from adult pulmonary tuberculosis. Due to hepatotoxicity worries, there are no dose–response studies in children. We designed a hollow fiber system model of disseminated intracellular tuberculosis with co-perfused three-dimensional organotypic liver modules to simultaneously test for efficacy and toxicity. We utilized pediatric pharmacokinetics of pyrazinamide and acetaminophen to determine dose-dependent pyrazinamide efficacy and hepatotoxicity. Acetaminophen concentrations that cause hepatotoxicity in children led to elevated liver function tests, while 100 mg/kg pyrazinamide did not. Surprisingly, pyrazinamide did not kill intracellular Mycobacterium tuberculosis up to fourfold the standard dose as monotherapy or as combination therapy, despite achieving high intracellular concentrations. Host-pathogen RNA-sequencing revealed lack of a pyrazinamide exposure transcript signature in intracellular bacteria or of phagolysosome acidification on pH imaging. Artificial intelligence algorithms confirmed that pyrazinamide was not predictive of good clinical outcomes in children ≤ 6 years who had extrapulmonary tuberculosis. Thus, adding a drug that works inside macrophages could benefit children with disseminated tuberculosis. Our in vitro model can be used to identify such new regimens that could accelerate cure while minimizing toxicity. We designed a pre-clinical of disseminated for simultaneous identification of toxicity and efficacy in children. The system is a co-culture of infected monocytes and 3 dimensional organotypic liver recapitulating children pharmacokinetics. Pyrazinamide, central drug in treatment regimen, had no effect as monotherapy or contribute to the combination therapy.
Due to fear of toxicity children are often not involved in clinical trials, and as a result the optimal treatment regimens are often lacking. As an example, toddlers and babies develop disseminated tuberculosis but are treated with regimens designed for adults with lung cavity disease. We designed a “glass-mouse” model of disseminated tuberculosis that simultaneously tests for the efficacy and toxicity of the anti-tuberculosis drugs for children with disseminated disease. We found that while not causing dose-dependent liver toxicity, one of the central drugs used to treat this children is likely not efficacious.
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Abstract
A major factor complicating efforts to control the tuberculosis epidemic is the long duration of treatment required to successfully clear the infection. One reason that long courses of treatment are required may be the fact that mycobacterial cells arise during the course of infection that are less susceptible to antibiotics. Here we describe the paradigms of phenotypic drug tolerance and resistance as they apply to mycobacteria. We then discuss the mechanisms by which phenotypically drug-tolerant and -resistant cells arise both at a population level and in specialized subpopulations of cells that may be especially important in allowing the bacterium to survive in the face of treatment. These include general mechanisms that have been shown to alter the susceptibility of mycobacteria to antibiotics including growth arrest, efflux pump induction, and biofilm formation. In addition, we discuss emerging data from single-cell studies of mycobacteria that have identified unique ways in which specialized subpopulations of cells arise that vary in their frequency, in their susceptibility to drug, and in their stability over time.
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60
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Fonseca JD, Knight GM, McHugh TD. The complex evolution of antibiotic resistance in Mycobacterium tuberculosis. Int J Infect Dis 2016; 32:94-100. [PMID: 25809763 DOI: 10.1016/j.ijid.2015.01.014] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 01/12/2015] [Accepted: 01/14/2015] [Indexed: 12/23/2022] Open
Abstract
Multidrug-resistant and extensively drug-resistant tuberculosis (TB) represent a major threat to the control of the disease worldwide. The mechanisms and pathways that result in the emergence and subsequent fixation of resistant strains of Mycobacterium tuberculosis are not fully understood and recent studies suggest that they are much more complex than initially thought. In this review, we highlight the exciting new areas of research within TB resistance that are beginning to fill these gaps in our understanding, whilst also raising new questions and providing future directions.
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Affiliation(s)
- J D Fonseca
- Centre for Clinical Microbiology, University College London, London, NW3 2PF, UK.
| | - G M Knight
- TB Modelling Group, TB Centre, Centre for the Mathematical Modelling of Infectious Diseases, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK
| | - T D McHugh
- Centre for Clinical Microbiology, University College London, London, NW3 2PF, UK
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Shenje J, Ifeoma Adimora-Nweke F, Ross IL, Ntsekhe M, Wiesner L, Deffur A, McIlleron HM, Pasipanodya J, Gumbo T, Mayosi BM. Poor Penetration of Antibiotics Into Pericardium in Pericardial Tuberculosis. EBioMedicine 2015; 2:1640-9. [PMID: 26870790 PMCID: PMC4740291 DOI: 10.1016/j.ebiom.2015.09.025] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 09/08/2015] [Accepted: 09/15/2015] [Indexed: 11/08/2022] Open
Abstract
Pericardial tuberculosis (TB) is associated with high therapy failure and high mortality rates. Antibiotics have to penetrate to site of infection at sufficient non-protein bound concentrations, and then enter bacteria to inhibit intracellular biochemical processes. The antibiotic concentrations achieved in pericardial fluid in TB pericarditis have never been measured before. We recruited two cohorts of patients with TB pericarditis, and left a pigtail catheter in-situ for serial drug concentration measurements over 24 h. Altogether, 704 drug concentrations were comodeled for pharmacokinetic analyses. The drug concentrations achieved in pericardial fluid were compared to the minimum inhibitory concentrations (MICs) of clinical Mycobacterium tuberculosis isolates. The total rifampicin concentration pericardial-to-serum ratios in 16 paired samples were 0.19 ± 0.33. The protein concentrations of the pericardial fluid in TB pericarditis were observed to be as high as in plasma. The non-protein bound rifampicin concentrations in pericardial fluid were 4-fold lower than rifampicin MICs in the pilot study, and the peak concentration was 0.125 versus 0.208 mg/L in the second (p = 0.001). The rifampicin clearance from pericardial fluid was 9.45 L/h versus 7.82 L/h in plasma (p = 0.002). Ethambutol peak concentrations had a pericardial-to-plasma ratio of 0.55 ± 0.22; free ethambutol peak concentrations were 2.30-lower than MICs (p < 0·001). The pericardial fluid pH was 7.34. The median pyrazinamide peak concentrations were 42.93 mg/L versus a median MIC of 800 mg/L at pH 7.34 (p < 0.0001). There was no significant difference between isoniazid pericardial fluid and plasma concentrations, and isoniazid peak concentrations were above MIC. This is the first study to measure anti-TB drug concentrations, pH and protein in the pericardial TB fluid. Pericardial concentrations of the key sterilizing drugs for TB were below MIC, which could contribute to poor outcomes. A new regimen that overcomes these limitations might need to be crafted. The amounts of antibiotics such as rifampicin, ethambutol, pyrazinamide and isoniazid used to treat TB pericarditis that enter pericardial fluid have up to now been unknown The study found that the pH in pericardial fluid was alkaline, which would mean that pyrazinamide effect would be compromised. The protein content in pericardial fluid was high, which would lead to low non-protein bound rifampicin and ethambutol concentrations The concentrations of rifampicin, ethambutol and pyrazinamide in pericardial were dramatically low and below the MICs of Mycobacterium tuberculosis
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Affiliation(s)
- Justin Shenje
- Divisions of Cardiology, Groote Schuur Hospital, University of Cape Town, Observatory, South Africa
| | - F Ifeoma Adimora-Nweke
- Center for Infectious Diseases Research and Experimental Therapeutics, Baylor Research Institute, Dallas, TX, USA
| | - Ian L Ross
- Endocrinology and Diabetes Medicine, Groote Schuur Hospital, University of Cape Town, Observatory, South Africa
| | - Mpiko Ntsekhe
- Divisions of Cardiology, Groote Schuur Hospital, University of Cape Town, Observatory, South Africa; Department of Medicine, Groote Schuur Hospital, University of Cape Town, Observatory, South Africa
| | - Lubbe Wiesner
- Clinical Pharmacology, Groote Schuur Hospital, University of Cape Town, Observatory, South Africa
| | - Armin Deffur
- Divisions of Cardiology, Groote Schuur Hospital, University of Cape Town, Observatory, South Africa
| | - Helen M McIlleron
- Clinical Pharmacology, Groote Schuur Hospital, University of Cape Town, Observatory, South Africa
| | - Jotam Pasipanodya
- Center for Infectious Diseases Research and Experimental Therapeutics, Baylor Research Institute, Dallas, TX, USA
| | - Tawanda Gumbo
- Center for Infectious Diseases Research and Experimental Therapeutics, Baylor Research Institute, Dallas, TX, USA; Department of Medicine, Groote Schuur Hospital, University of Cape Town, Observatory, South Africa
| | - Bongani M Mayosi
- Divisions of Cardiology, Groote Schuur Hospital, University of Cape Town, Observatory, South Africa; Department of Medicine, Groote Schuur Hospital, University of Cape Town, Observatory, South Africa
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Gumbo T, Pasipanodya JG, Romero K, Hanna D, Nuermberger E. Forecasting Accuracy of the Hollow Fiber Model of Tuberculosis for Clinical Therapeutic Outcomes. Clin Infect Dis 2015. [DOI: 10.1093/cid/civ427] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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63
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Pasipanodya JG, Nuermberger E, Romero K, Hanna D, Gumbo T. Systematic Analysis of Hollow Fiber Model of Tuberculosis Experiments. Clin Infect Dis 2015. [DOI: 10.1093/cid/civ425] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
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Gumbo T, Pasipanodya JG, Nuermberger E, Romero K, Hanna D. Correlations Between the Hollow Fiber Model of Tuberculosis and Therapeutic Events in Tuberculosis Patients: Learn and Confirm. Clin Infect Dis 2015. [DOI: 10.1093/cid/civ426] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Whole Genome Sequencing Investigation of a Tuberculosis Outbreak in Port-au-Prince, Haiti Caused by a Strain with a "Low-Level" rpoB Mutation L511P - Insights into a Mechanism of Resistance Escalation. PLoS One 2015; 10:e0129207. [PMID: 26039194 PMCID: PMC4454571 DOI: 10.1371/journal.pone.0129207] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 05/07/2015] [Indexed: 12/30/2022] Open
Abstract
The World Health Organization recommends diagnosing Multidrug-Resistant Tuberculosis (MDR-TB) in high burden countries by detection of mutations in Rifampin (RIF) Resistance Determining Region of Mycobacterium tuberculosis rpoB gene with rapid molecular tests GeneXpert MTB/RIF and Hain MTBDRplus. Such mutations are found in >95% of Mycobacterium tuberculosis strains resistant to RIF by conventional culture-based drug susceptibility testing (DST). However routine diagnostic screening with molecular tests uncovered specific “low level” rpoB mutations conferring resistance to RIF below the critical concentration of 1 μg/ml in some phenotypically susceptible strains. Cases with discrepant phenotypic (susceptible) and genotypic (resistant) results for resistance to RIF account for at least 10% of resistant diagnoses by molecular tests and urgently require new guidelines to inform therapeutic decision making. Eight strains with a “low level” rpoB mutation L511P were isolated by GHESKIO laboratory between 2008 and 2012 from 6 HIV-negative and 2 HIV-positive patients during routine molecular testing. Five isolates with a single L511P mutation and two isolates with double mutation L511P&M515T had MICs for RIF between 0.125 and 0.5 μg/ml and tested susceptible in culture-based DST. The eighth isolate carried a double mutation L511P&D516C and was phenotypically resistant to RIF. All eight strains shared the same spoligotype SIT 53 commonly found in Haiti but classic epidemiological investigation failed to uncover direct contacts between the patients. Whole Genome Sequencing (WGS) revealed that L511P cluster isolates resulted from a clonal expansion of an ancestral strain resistant to Isoniazid and to a very low level of RIF. Under the selective pressure of RIF-based therapy the strain acquired mutation in the M306 codon of embB followed by secondary mutations in rpoB and escalation of resistance level. This scenario highlights the importance of subcritical resistance to RIF for both clinical management of patients and public health and provides support for introducing rpoB mutations as proxy for MICs into laboratory diagnosis of RIF resistance. This study illustrates that WGS is a promising multi-purpose genotyping tool for high-burden settings as it provides both “gold standard” sequencing results for prediction of drug susceptibility and a high-resolution data for epidemiological investigation in a single assay.
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Gumbo T, Lenaerts AJ, Hanna D, Romero K, Nuermberger E. Nonclinical Models for Antituberculosis Drug Development: A Landscape Analysis. J Infect Dis 2015; 211 Suppl 3:S83-95. [DOI: 10.1093/infdis/jiv183] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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Gumbo T, Angulo-Barturen I, Ferrer-Bazaga S. Pharmacokinetic-Pharmacodynamic and Dose-Response Relationships of Antituberculosis Drugs: Recommendations and Standards for Industry and Academia. J Infect Dis 2015; 211 Suppl 3:S96-S106. [DOI: 10.1093/infdis/jiu610] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Zhang Z, Yan J, Xu K, Ji Z, Li L. Tetrandrine reverses drug resistance in isoniazid and ethambutol dual drug-resistant Mycobacterium tuberculosis clinical isolates. BMC Infect Dis 2015; 15:153. [PMID: 25887373 PMCID: PMC4417324 DOI: 10.1186/s12879-015-0905-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 03/13/2015] [Indexed: 02/04/2023] Open
Abstract
Background Tetrandrine is a natural chemical product purified from fourstamen stephania root which recently has been shown to act similarly as synthesized drug efflux pump inhibitor verapamil. The aim of the study is to examine whether tetrandrine could potentiate anti-tubercular drugs to which Mycobacterium tuberculosis (MTB) has turned resistant via efflux mechanisms. Methods We screened 200 MTB clinical isolates using drug sensitivity test to look for those who have turned resistant to the drugs most probably due to efflux mechanisms. We found 29 isoniazid (INH) and ethambutol (EMB) - dual resistant (IEDR) strains. Then we tested if treatment with tetrandrine or verapamil could reverse drug resistance to INH and/or EMB in IEDR isolates. Results There is a parallel resistance among EMB- and INH-resistant strains in the tested clinical isolates. Among INH-resistant strains, 65% was also EMB-resistant. This suggests an involvement of efflux mechanisms which can lead to dual drug resistance in IEDR clinical isolates. Similar to a synthesized efflux pump inhibitor verapamil, tetrandrine treatment together with INH or EMB brought down the MICs from the clinical level of drug resistance to the sensitive range of both drugs. The effective rate reached 82% among IEDR clinical isolates. Conclusions Combinational application of tetrandrine with INH or EMB increased drug efficacy. Drugs like tetrandrine may help to reduce drug dosage thus alleviate side effects.
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Affiliation(s)
- Zhe Zhang
- Research Center of Infection and Immunity, Department of Microbiology and Parasitology, School of Basic Medical Sciences, School of Medicine, Zhejiang University, Hangzhou, China.
| | - Jie Yan
- Research Center of Infection and Immunity, Department of Microbiology and Parasitology, School of Basic Medical Sciences, School of Medicine, Zhejiang University, Hangzhou, China.
| | - Kaijin Xu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital of School of Medicine, Zhejiang University, 15th floor, Building 6A, No. 79 Qingchun Road, Shangcheng District, Hangzhou, 310003, Zhejiang Province, China.
| | - Zhongkang Ji
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital of School of Medicine, Zhejiang University, 15th floor, Building 6A, No. 79 Qingchun Road, Shangcheng District, Hangzhou, 310003, Zhejiang Province, China.
| | - Lanjuan Li
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital of School of Medicine, Zhejiang University, 15th floor, Building 6A, No. 79 Qingchun Road, Shangcheng District, Hangzhou, 310003, Zhejiang Province, China.
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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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Rapid drug tolerance and dramatic sterilizing effect of moxifloxacin monotherapy in a novel hollow-fiber model of intracellular Mycobacterium kansasii disease. Antimicrob Agents Chemother 2015; 59:2273-9. [PMID: 25645830 DOI: 10.1128/aac.04441-14] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mycobacterium kansasii is the second most common mycobacterial cause of lung disease. Standard treatment consists of rifampin, isoniazid, and ethambutol for at least 12 months after negative sputum. Thus, shorter-duration therapies are needed. Moxifloxacin has good MICs for M. kansasii. However, good preclinical models to identify optimal doses currently are lacking. We developed a novel hollow fiber system model of intracellular M. kansasii infection. We indexed the efficacy of the standard combination regimen, which was a kill rate of -0.08 ± 0.05 log10 CFU/ml/day (r(2) = 0.99). We next performed moxifloxacin dose-effect and dose-scheduling studies at a half-life of 11.1 ± 6.47 h. Some systems also were treated with the efflux pump inhibitor reserpine. The highest moxifloxacin exposure, as well as lower exposures plus reserpine, sterilized the cultures by day 7. This suggests that efflux pump-mediated tolerance at low ratios of the area under the concentration-time curve from 0 to 24 h (AUC0 - 24) to MICs is an early bacterial defense mechanism but is overcome by higher exposures. The highest rate of moxifloxacin monotherapy sterilization was -0.82 ± 0.15 log10 CFU/ml/day (r(2) = 0.97). The moxifloxacin exposure associated with 80% of maximal kill (EC80) was an AUC0-24/MIC of 317 (the non-protein-bound moxifloxacin AUC0-24/MIC was 158.5). We performed Monte Carlo simulations of 10,000 patients in order to identify the moxifloxacin dose that would achieve or exceed the EC80. The simulations revealed an optimal moxifloxacin dose of 800 mg a day. The MIC susceptibility breakpoint at this dose was 0.25 mg/liter. Thus, moxifloxacin, at high enough doses, is suitable to study in patients for the potential to add rapid sterilization to the standard regimen.
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Hiruy H, Rogers Z, Mbowane C, Adamson J, Ngotho L, Karim F, Gumbo T, Bishai W, Jeena P. Subtherapeutic concentrations of first-line anti-TB drugs in South African children treated according to current guidelines: the PHATISA study. J Antimicrob Chemother 2014; 70:1115-23. [PMID: 25505005 DOI: 10.1093/jac/dku478] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES There is a paucity of evidence regarding the optimal dosing of anti-TB drugs in children. The aim of this study was to identify the pharmacokinetic parameters of first-line anti-TB drugs and the concentrations achieved after implementation of the 2010 WHO-recommended paediatric dosages. METHODS We conducted a prospective, observational pharmacokinetic study in children 10 years old or younger who were on isoniazid, rifampicin, pyrazinamide and ethambutol therapy in Durban, KwaZulu-Natal, South Africa. Blood was collected at six timepoints over a 24 h period, chosen using optimal sampling theory. The drug concentrations were simultaneously modelled to identify the compartmental pharmacokinetics of each drug in each child, using the ADAPT program. RESULTS The best six sampling timepoints in children were identified as 0 (pre-dose) and 0.42, 1.76, 3.37, 10.31 and 24 h post-dose. Thirty-one children were recruited and blood was drawn at these timepoints. Rifampicin, ethambutol and pyrazinamide were best described using a one-compartment model, while isoniazid was best described with a two-compartment model. Only 2/31 (6%), 20/31 (65%), 17/31 (55%) and 2/13 (15%) of children attained the WHO 2 h target therapeutic concentrations of rifampicin, isoniazid, pyrazinamide and ethambutol, respectively. Moreover, only 24/31 (77%), 6/31 (19%) and 8/31 (26%) achieved the AUCs associated with an optimal clinical response to rifampicin, pyrazinamide and isoniazid, respectively. No single risk factor was significantly associated with below-normal drug levels. CONCLUSIONS The drug concentrations of all first-line anti-TB drugs were markedly below the target therapeutic concentrations in most South African children who received the revised WHO-recommended paediatric weight-based dosages.
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Affiliation(s)
- Hiwot Hiruy
- Center for Tuberculosis Research, Department of Medicine, JHU, Baltimore, MD 21287, USA
| | - Zoe Rogers
- Kwazulu-Natal Research Institute for TB and HIV, Durban 4001, South Africa
| | - Chris Mbowane
- Department of Pediatrics, Nelson Mandela School of Medicine, UKZN, Durban 4001, South Africa
| | - John Adamson
- Kwazulu-Natal Research Institute for TB and HIV, Durban 4001, South Africa
| | - Lihle Ngotho
- Kwazulu-Natal Research Institute for TB and HIV, Durban 4001, South Africa
| | - Farina Karim
- Kwazulu-Natal Research Institute for TB and HIV, Durban 4001, South Africa
| | - Tawanda Gumbo
- Office of Global Health, University of Texas Southwestern Medical School, Dallas, TX 75390, USA
| | - William Bishai
- Center for Tuberculosis Research, Department of Medicine, JHU, Baltimore, MD 21287, USA Kwazulu-Natal Research Institute for TB and HIV, Durban 4001, South Africa Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Prakash Jeena
- Department of Pediatrics, Nelson Mandela School of Medicine, UKZN, Durban 4001, South Africa
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An upstream truncation of the furA-katG operon confers high-level isoniazid resistance in a Mycobacterium tuberculosis clinical isolate with no known resistance-associated mutations. Antimicrob Agents Chemother 2014; 58:6093-100. [PMID: 25092698 DOI: 10.1128/aac.03277-14] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Although the major causes of isoniazid (INH) resistance in Mycobacterium tuberculosis are confined to structural mutations in katG and promoter mutations in the mabA-inhA operon, a significant proportion of INH-resistant strains have unknown resistance mechanisms. Recently, we identified a high-level INH-resistant M. tuberculosis clinical isolate, GB005, with no known resistance-associated mutations. A comprehensive study was performed to investigate the molecular basis of drug resistance in this strain. Although no mutations were found throughout the katG and furA-katG intergenic region, the katG expression and the catalase activity were greatly diminished compared to those in H37Rv (P < 0.01). Northern blotting revealed that the katG transcript from the isolate was smaller than that of H37Rv. Sequencing analysis of furA and upstream genes discovered a 7.2-kb truncation extended from the 96th base preceding the initiation codon of katG. Complementation of the M. tuberculosis Δ(furA-katG) strain with katG and different portions of the truncated region identified a 134-bp upstream fragment of furA that was essential for full catalase activity and INH susceptibility in M. tuberculosis. The promoter activity of this fragment was also shown to be stronger than that of the furA-katG intergenic region (P < 0.01). Collectively, these findings demonstrate that deletion of the 134-bp furA upstream fragment is responsible for the reduction in katG expression, resulting in INH resistance in GB005. To our knowledge, this is the first report showing that deletion of the upstream region preceding the furA-katG operon causes high-level INH resistance in a clinical isolate of M. tuberculosis.
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Redefining multidrug-resistant tuberculosis based on clinical response to combination therapy. Antimicrob Agents Chemother 2014; 58:6111-5. [PMID: 25092691 DOI: 10.1128/aac.03549-14] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In tuberculosis treatment, susceptibility is defined by a critical concentration of 1.0 mg/liter for rifampin and 0.2 or 1.0 mg/liter for low- and high-level isoniazid resistance on the basis of an epidemiologic cutoff method that uses the distribution of the MICs for isolates. However, pharmacokinetics-pharmacodynamics-based clinical trial simulations suggested that the breakpoints should be 0.0625 mg/liter for rifampin and 0.0312 or 0.125 mg/liter for isoniazid. We examined the outcomes of 36 patients with drug-susceptible tuberculosis whose rifampin and isoniazid MICs were determined, whose plasma drug concentrations were also measured, and who were part of a prospective cohort study in Western Cape, South Africa. We performed classification and regression tree analysis to identify clinical and laboratory factors that predicted 2-month sputum conversion rates and long-term clinical outcomes. Poor long-term clinical outcomes were defined as microbiological failure, relapse, or death within a 2-year follow-up period. Peak drug concentrations and areas under the concentration-time curve were most predictive of outcomes and constituted the primary node, similar to our findings on the larger cohort. However, rifampin and isoniazid MICs improved the predictive capacity of the primary decision node by 20 and 17%, respectively, for these 36 patients. The rifampin MIC cutoff above which there was therapy failure was 0.125 mg/liter, while that of isoniazid was 0.0312 mg/liter; these are similar to those derived in clinical trial simulations. The critical concentrations used to define multidrug resistance for clinical decision making should take clinical outcomes into account.
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Magis-Escurra C, Later-Nijland HMJ, Alffenaar JWC, Broeders J, Burger DM, van Crevel R, Boeree MJ, Donders ART, van Altena R, van der Werf TS, Aarnoutse RE. Population pharmacokinetics and limited sampling strategy for first-line tuberculosis drugs and moxifloxacin. Int J Antimicrob Agents 2014; 44:229-34. [PMID: 24985091 DOI: 10.1016/j.ijantimicag.2014.04.019] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 04/17/2014] [Accepted: 04/23/2014] [Indexed: 10/25/2022]
Abstract
Therapeutic drug monitoring (TDM) of tuberculosis (TB) drugs currently focuses on peak plasma concentrations, yet total exposure [area under the 24-h concentration-time curve (AUC₀₋₂₄)] is probably most relevant to the efficacy of these drugs. We therefore assessed population AUC₀₋₂₄ data for all four first-line TB drugs (rifampicin, isoniazid, pyrazinamide and ethambutol) as well as moxifloxacin and developed limited sampling strategies to estimate AUC₀₋₂₄ values conveniently. AUC₀₋₂₄ and other pharmacokinetic (PK) parameters were determined following intensive PK sampling in two Dutch TB referral centres. Best subset selection multiple linear regression was performed to derive limited sampling equations. Median percentage prediction error and median absolute percentage prediction error were calculated via jackknife analysis to evaluate bias and imprecision of the predictions. Geometric mean AUC₀₋₂₄ values for rifampicin, isoniazid, pyrazinamide, ethambutol and moxifloxacin were 41.1, 15.2, 380, 25.5 and 33.6 hmg/L, respectively. Limited sampling at various fixed sampling points enabled an accurate and precise prediction of AUC₀₋₂₄ values of all drugs separately and simultaneously. In the absence of clinically validated target values for AUC₀₋₂₄, average AUC₀₋₂₄ values can be used as reference values in TDM. Limited sampling of AUC₀₋₂₄ is feasible in many settings and allows for TDM to be performed at a larger scale.
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Affiliation(s)
- C Magis-Escurra
- Radboud University Medical Centre, Department of Pulmonary diseases, Nijmegen and University Centre for Chronic Diseases Dekkerswald, Groesbeek, The Netherlands.
| | - H M J Later-Nijland
- Radboud University Medical Centre, Department of Pharmacy, Nijmegen, The Netherlands
| | - J W C Alffenaar
- University Medical Centre Groningen, Department of Hospital and Clinical Pharmacy, Groningen, The Netherlands
| | - J Broeders
- Radboud University Medical Centre, Department of Pharmacy, Nijmegen, The Netherlands
| | - D M Burger
- Radboud University Medical Centre, Department of Pharmacy, Nijmegen, The Netherlands
| | - R van Crevel
- Radboud University Medical Centre, Department of Internal Medicine, Nijmegen, The Netherlands
| | - M J Boeree
- Radboud University Medical Centre, Department of Pulmonary diseases, Nijmegen and University Centre for Chronic Diseases Dekkerswald, Groesbeek, The Netherlands
| | - A R T Donders
- Radboud University Medical Centre, Department for Epidemiology, Biostatistics and HTA, Nijmegen, The Netherlands
| | - R van Altena
- University Medical Centre Groningen, Tuberculosis Centre Beatrixoord, Haren, The Netherlands
| | - T S van der Werf
- University Medical Centre Groningen, Tuberculosis Centre Beatrixoord, Haren, The Netherlands; University Medical Centre Groningen, Department of Internal Medicine, Groningen, The Netherlands
| | - R E Aarnoutse
- Radboud University Medical Centre, Department of Pharmacy, Nijmegen, The Netherlands
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Dheda K, Gumbo T, Gandhi NR, Murray M, Theron G, Udwadia Z, Migliori GB, Warren R. Global control of tuberculosis: from extensively drug-resistant to untreatable tuberculosis. THE LANCET RESPIRATORY MEDICINE 2014; 2:321-38. [PMID: 24717628 DOI: 10.1016/s2213-2600(14)70031-1] [Citation(s) in RCA: 200] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Extensively drug-resistant tuberculosis is a burgeoning global health crisis mainly affecting economically active young adults, and has high mortality irrespective of HIV status. In some countries such as South Africa, drug-resistant tuberculosis represents less than 3% of all cases but consumes more than a third of the total national budget for tuberculosis, which is unsustainable and threatens to destabilise national tuberculosis programmes. However, concern about drug-resistant tuberculosis has been eclipsed by that of totally and extremely drug-resistant tuberculosis--ie, resistance to all or nearly all conventional first-line and second-line antituberculosis drugs. In this Review, we discuss the epidemiology, pathogenesis, diagnosis, management, implications for health-care workers, and ethical and medicolegal aspects of extensively drug-resistant tuberculosis and other resistant strains. Finally, we discuss the emerging problem of functionally untreatable tuberculosis, and the issues and challenges that it poses to public health and clinical practice. The emergence and growth of highly resistant strains of tuberculosis make the development of new drugs and rapid diagnostics for tuberculosis--and increased funding to strengthen global control efforts, research, and advocacy--even more pressing.
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Affiliation(s)
- Keertan Dheda
- Lung Infection and Immunity Unit, Division of Pulmonology and UCT Lung Institute, Department of Medicine, University of Cape Town, Cape Town, South Africa; Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa.
| | - Tawanda Gumbo
- Office of Global Health and Department of Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Neel R Gandhi
- Departments of Epidemiology, Global Health, and Infectious Diseases, Rollins School of Public Health, Emory University, Atlanta, GA, USA
| | - Megan Murray
- Department of Global Health and Social Medicine, Harvard Medical School, Boston, MA, USA
| | - Grant Theron
- Lung Infection and Immunity Unit, Division of Pulmonology and UCT Lung Institute, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | | | - G B Migliori
- WHO Collaborating Centre for TB and Lung Diseases, Fondazione S Maugeri, Care and Research Institute, Tradate, Italy
| | - Robin Warren
- DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg, South Africa
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Reynolds J, Heysell SK. Understanding pharmacokinetics to improve tuberculosis treatment outcome. Expert Opin Drug Metab Toxicol 2014; 10:813-23. [PMID: 24597717 DOI: 10.1517/17425255.2014.895813] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
INTRODUCTION Tuberculosis (TB) remains the leading cause of death from a curable infectious disease; drug-resistant TB threatens to dismantle all prior gains in global control. Suboptimal circulating anti-TB drug concentrations can lead to lack of cure and acquired drug resistance. AREAS COVERED This review will introduce pharmacokinetic parameters for key anti-TB drugs, as well as the indications and limitations of measuring these parameters in clinical practice. Current and novel methodologies for delivering anti-TB pharmacokinetic-pharmacodynamic data are highlighted and gaps in operational research described. EXPERT OPINION Individual pharmacokinetic variability is commonplace, underappreciated and difficult to predict without therapeutic drug monitoring (TDM). Pharmacokinetic thresholds associated with poor TB treatment outcome in drug-susceptible TB have recently been described and may now guide the application of TDM, but require validation in a variety of settings and comorbidities. Dried blood spots for TDM and prepackaged multidrug plates for minimum inhibitory concentration testing will overcome barriers of accessibility and represent areas for innovation. Operationalizing pharmacokinetics has the potential to improve TB outcomes in the most difficult-to-treat forms of the disease such as multidrug resistance. Clinical studies in these areas are eagerly anticipated and we expect will better define the rational introduction of novel therapeutics.
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Affiliation(s)
- Jonathan Reynolds
- University of Virginia, School of Medicine , PO Box 801340, Charlottesville, VA 22908-1340 , USA
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Pusch T, Pasipanodya JG, Hall RG, Gumbo T. Therapy duration and long-term outcomes in extra-pulmonary tuberculosis. BMC Infect Dis 2014; 14:115. [PMID: 24580808 PMCID: PMC3943436 DOI: 10.1186/1471-2334-14-115] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 02/18/2014] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Tuberculosis is classified as either pulmonary or extra-pulmonary (EPTB). While much focus has been paid to pulmonary tuberculosis, EPTB has received scant attention. Moreover, EPTB is viewed as one wastebasket diagnosis, as "the other" which is not pulmonary. METHODS This is a retrospective cohort study of all patients treated for EPTB in the state of Texas between January 2000 and December 2005, who had no pulmonary disease. Clinical and epidemiological factors were abstracted from electronic records of the Report of Verified Case of Tuberculosis. The long-term outcome, which is death by December 2011, was established using the Social Security Administration Death Master File database. Survival in EPTB patients was compared to those with latent tuberculosis, as well as between different types of EPTB, using Cox proportional hazard models. A hybrid of the machine learning method of classification and regression tree analyses and standard regression models was used to identify high-order interactions and clinical factors predictive of long-term all-cause mortality. RESULTS Four hundred and thirty eight patients met study criteria; the median study follow-up period for the cohort was 7.8 (inter-quartile range 6.0-10.1) years. The overall all-cause mortality rate was 0.025 (95% confidence interval [CI]: 0.021-0.030) per 100 person-year of follow-up. The significant predictors of poor long-term outcome were age (hazard ratio [HR] for each year of age-at-diagnosis was 1.05 [CI: 1.04-1.06], treatment duration, type of EPTB and HIV-infection (HR = 2.16; CI: 1.22, 3.83). Mortality in genitourinary tuberculosis was no different from latent tuberculosis, while meningitis had the poorest long-term outcome of 46.2%. Compared to meningitis the HR for death was 0.50 (CI: 0.27-0.91) for lymphatic disease, 0.42 (CI: 0.21-0.81) for bone/joint disease, and 0.59 (CI: 0.27-1.31) for peritonitis. The relationship between mortality and therapy duration for each type of EPTB was a unique "V" shaped curve, with the lowest mortality observed at different therapy durations for each, beyond which mortality increased. CONCLUSIONS EPTB is comprised of several different diseases with different outcomes and durations of therapy. The "V" shaped relationship between therapy duration and outcome leads to the hypothesis that longer duration of therapy may lead to higher patient mortality.
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Affiliation(s)
- Tobias Pusch
- Department of Medicine, University of Texas Southwestern Medical Center, Dallas, USA
| | - Jotam G Pasipanodya
- Department of Medicine, University of Texas Southwestern Medical Center, Dallas, USA
- Office of Global Health, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, Texas 75390-8504, USA
| | - Ronald G Hall
- Department of Pharmacy Practice, Texas Tech University Health Sciences Center, School of Pharmacy, 4500 Lancaster, Dallas, Texas 75216, USA
| | - Tawanda Gumbo
- Department of Medicine, University of Texas Southwestern Medical Center, Dallas, USA
- Office of Global Health, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, Texas 75390-8504, USA
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78
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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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79
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Pasipanodya JG, McIlleron H, Burger A, Wash PA, Smith P, Gumbo T. Serum drug concentrations predictive of pulmonary tuberculosis outcomes. J Infect Dis 2013; 208:1464-73. [PMID: 23901086 DOI: 10.1093/infdis/jit352] [Citation(s) in RCA: 333] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Based on a hollow-fiber system model of tuberculosis, we hypothesize that microbiologic failure and acquired drug resistance are primarily driven by low drug concentrations that result from pharmacokinetic variability. METHODS Clinical and pharmacokinetic data were prospectively collected from 142 tuberculosis patients in Western Cape, South Africa. Compartmental pharmacokinetic parameters of isoniazid, rifampin, and pyrazinamide were identified for each patient. Patients were then followed for up to 2 years. Classification and regression tree analysis was used to identify and rank clinical predictors of poor long-term outcome such as microbiologic failure or death, or relapse. RESULTS Drug concentrations and pharmacokinetics varied widely between patients. Poor long-term outcomes were encountered in 35 (25%) patients. The 3 top predictors of poor long-term outcome, by rank of importance, were a pyrazinamide 24-hour area under the concentration-time curve (AUC) ≤ 363 mg·h/L, rifampin AUC ≤ 13 mg·h/L, and isoniazid AUC ≤ 52 mg·h/L. Poor outcomes were encountered in 32/78 patients with the AUC of at least 1 drug below the identified threshold vs 3/64 without (odds ratio = 14.14; 95% confidence interval, 4.08-49.08). Low rifampin and isoniazid peak and AUC concentrations preceded all cases of acquired drug resistance. CONCLUSIONS Low drug AUCs are predictive of clinical outcomes in tuberculosis patients.
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Affiliation(s)
- Jotam G Pasipanodya
- Office of Global Health, University of Texas Southwestern Medical Center, Dallas, Texas
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80
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Gumbo T. Biological variability and the emergence of multidrug-resistant tuberculosis. Nat Genet 2013; 45:720-1. [DOI: 10.1038/ng.2675] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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81
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Szumowski JD, Adams KN, Edelstein PH, Ramakrishnan L. Antimicrobial efflux pumps and Mycobacterium tuberculosis drug tolerance: evolutionary considerations. Curr Top Microbiol Immunol 2013; 374:81-108. [PMID: 23242857 PMCID: PMC3859842 DOI: 10.1007/82_2012_300] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The need for lengthy treatment to cure tuberculosis stems from phenotypic drug resistance, also known as drug tolerance, which has been previously attributed to slowed bacterial growth in vivo. We discuss recent findings that challenge this model and instead implicate macrophage-induced mycobacterial efflux pumps in antimicrobial tolerance. Although mycobacterial efflux pumps may have originally served to protect against environmental toxins, in the pathogenic mycobacteria, they appear to have been repurposed for intracellular growth. In this light, we discuss the potential of efflux pump inhibitors such as verapamil to shorten tuberculosis treatment by their dual inhibition of tolerance and growth.
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Affiliation(s)
- John D Szumowski
- Department of Medicine (Division of Infectious Diseases), University of Washington, Seattle, WA, USA,
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82
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Martins M. Is adjuvant therapy a potential road for fighting Mycobacterium tuberculosis resistance? Expert Rev Anti Infect Ther 2012; 10:1225-7. [PMID: 23241177 DOI: 10.1586/eri.12.103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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83
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Mycobacterial shuttle vectors designed for high-level protein expression in infected macrophages. Appl Environ Microbiol 2012; 78:6829-37. [PMID: 22820329 DOI: 10.1128/aem.01674-12] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mycobacterial shuttle vectors contain dual origins of replication for growth in both Escherichia coli and mycobacteria. One such vector, pSUM36, was re-engineered for high-level protein expression in diverse bacterial species. The modified vector (pSUM-kan-MCS2) enabled green fluorescent protein expression in E. coli, Mycobacterium smegmatis, and M. avium at levels up to 50-fold higher than that detected with the parental vector, which was originally developed with a lacZα promoter. This high-level fluorescent protein expression allowed easy visualization of M. smegmatis and M. avium in infected macrophages. The M. tuberculosis gene esat-6 was cloned in place of the green fluorescence protein gene (gfp) to determine the impact of ESAT-6 on the innate inflammatory response. The modified vector (pSUM-kan-MCS2) yielded high levels of ESAT-6 expression in M. smegmatis. The ability of ESAT-6 to suppress innate inflammatory pathways was assayed with a novel macrophage reporter cell line, designed with an interleukin-6 (IL-6) promoter-driven GFP cassette. This stable cell line fluoresces in response to diverse mycobacterial strains and stimuli, such as lipopolysaccharide. M. smegmatis clones expressing high levels of ESAT-6 failed to attenuate IL-6-driven GFP expression. Pure ESAT-6, produced in E. coli, was insufficient to suppress a strong inflammatory response elicited by M. smegmatis or lipopolysaccharide, with ESAT-6 itself directly activating the IL-6 pathway. In summary, a pSUM-protein expression vector and a mammalian IL-6 reporter cell line provide new tools for understanding the pathogenic mechanisms deployed by various mycobacterial species.
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84
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The antibiotic resistance arrow of time: efflux pump induction is a general first step in the evolution of mycobacterial drug resistance. Antimicrob Agents Chemother 2012; 56:4806-15. [PMID: 22751536 DOI: 10.1128/aac.05546-11] [Citation(s) in RCA: 136] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We hypothesize that low-level efflux pump expression is the first step in the development of high-level drug resistance in mycobacteria. We performed 28-day azithromycin dose-effect and dose-scheduling studies in our hollow-fiber model of disseminated Mycobacterium avium-M. intracellulare complex. Both microbial kill and resistance emergence were most closely linked to the within-macrophage area under the concentration-time curve (AUC)/MIC ratio. Quantitative PCR revealed that subtherapeutic azithromycin exposures over 3 days led to a 56-fold increase in expression of MAV_3306, which encodes a putative ABC transporter, and MAV_1406, which encodes a putative major facilitator superfamily pump, in M. avium. By day 7, a subpopulation of M. avium with low-level resistance was encountered and exhibited the classic inverted U curve versus AUC/MIC ratios. The resistance was abolished by an efflux pump inhibitor. While the maximal microbial kill started to decrease after day 7, a population with high-level azithromycin resistance appeared at day 28. This resistance could not be reversed by efflux pump inhibitors. Orthologs of pumps encoded by MAV_3306 and MAV_1406 were identified in Mycobacterium tuberculosis, Mycobacterium leprae, Mycobacterium marinum, Mycobacterium abscessus, and Mycobacterium ulcerans. All had highly conserved protein secondary structures. We propose that induction of several efflux pumps is the first step in a general pathway to drug resistance that eventually leads to high-level chromosomal-mutation-related resistance in mycobacteria as ordered events in an "antibiotic resistance arrow of time."
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85
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Machado D, Couto I, Perdigão J, Rodrigues L, Portugal I, Baptista P, Veigas B, Amaral L, Viveiros M. Contribution of efflux to the emergence of isoniazid and multidrug resistance in Mycobacterium tuberculosis. PLoS One 2012; 7:e34538. [PMID: 22493700 PMCID: PMC3321020 DOI: 10.1371/journal.pone.0034538] [Citation(s) in RCA: 153] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 03/01/2012] [Indexed: 11/19/2022] Open
Abstract
Multidrug resistant (MDR) tuberculosis is caused by Mycobacterium tuberculosis resistant to isoniazid and rifampicin, the two most effective drugs used in tuberculosis therapy. Here, we investigated the mechanism by which resistance towards isoniazid develops and how overexpression of efflux pumps favors accumulation of mutations in isoniazid targets, thus establishing a MDR phenotype. The study was based on the in vitro induction of an isoniazid resistant phenotype by prolonged serial exposure of M. tuberculosis strains to the critical concentration of isoniazid employed for determination of drug susceptibility testing in clinical isolates. Results show that susceptible and rifampicin monoresistant strains exposed to this concentration become resistant to isoniazid after three weeks; and that resistance observed for the majority of these strains could be reduced by means of efflux pumps inhibitors. RT-qPCR assessment of efflux pump genes expression showed overexpression of all tested genes. Enhanced real-time efflux of ethidium bromide, a common efflux pump substrate, was also observed, showing a clear relation between overexpression of the genes and increased efflux pump function. Further exposure to isoniazid resulted in the selection and stabilization of spontaneous mutations and deletions in the katG gene along with sustained increased efflux activity. Together, results demonstrate the relevance of efflux pumps as one of the factors of isoniazid resistance in M. tuberculosis. These results support the hypothesis that activity of efflux pumps allows the maintenance of an isoniazid resistant population in a sub-optimally treated patient from which isoniazid genetically resistant mutants emerge. Therefore, the use of inhibitors of efflux should be considered in the development of new therapeutic strategies for preventing the emergence of MDR-TB during treatment.
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Affiliation(s)
- Diana Machado
- Grupo de Micobactérias, Unidade de Microbiologia Médica, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa (IHMT/UNL), Lisboa, Portugal
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86
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Goldberg DE, Siliciano RF, Jacobs WR. Outwitting evolution: fighting drug-resistant TB, malaria, and HIV. Cell 2012; 148:1271-83. [PMID: 22424234 PMCID: PMC3322542 DOI: 10.1016/j.cell.2012.02.021] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Indexed: 11/20/2022]
Abstract
Although caused by vastly different pathogens, the world's three most serious infectious diseases, tuberculosis, malaria, and HIV-1 infection, share the common problem of drug resistance. The pace of drug development has been very slow for tuberculosis and malaria and rapid for HIV-1. But for each disease, resistance to most drugs has appeared quickly after the introduction of the drug. Learning how to manage and prevent resistance is a major medical challenge that requires an understanding of the evolutionary dynamics of each pathogen. This Review summarizes the similarities and differences in the evolution of drug resistance for these three pathogens.
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Affiliation(s)
- Daniel E Goldberg
- Department of Medicine and Howard Hughes Medical Institute, Washington University School of Medicine, St. Louis, MO 63110, USA
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87
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Generation of a novel nucleic acid-based reporter system to detect phenotypic susceptibility to antibiotics in Mycobacterium tuberculosis. mBio 2012; 3:mBio.00312-11. [PMID: 22415006 PMCID: PMC3312217 DOI: 10.1128/mbio.00312-11] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We designed, constructed, and evaluated a prototype novel reporter system comprised of two functional cassettes: (i) the SP6 RNA polymerase gene under transcriptional control of a promoter active in mycobacteria and (ii) the consensus SP6 polymerase promoter that directs expression of an otherwise unexpressed sequence. We incorporated the reporter system into a mycobacteriophage for delivery into viable Mycobacterium tuberculosis, and introduction led to synthesis of an SP6 polymerase-dependent surrogate marker RNA that we detected by reverse transcriptase PCR (RT-PCR). The reporter confirmed the susceptibility profile of both drug-susceptible and drug-resistant M. tuberculosis strains exposed to first-line antitubercular drugs and required as little as 16 h of exposure to antibacterial agents targeting bacterial metabolic processes to accurately read the reaction. The reporter system translated the bacterial phenotype into a language interpretable by rapid and sensitive nucleic acid detection. As a phenotypic assay that works only on viable M. tuberculosis, it could be used to rapidly assess resistance to any drug, including drugs for which the mechanism of resistance is unknown or which result from many potential known (and unknown) genetic alterations. The ability to detect antibiotic resistance of slow-growing bacteria (i.e., Mycobacterium tuberculosis) is hampered by two factors, the time to detection (weeks to months) and the resistance mechanism (unknown for many drugs), delaying the appropriate treatment of patients with drug-resistant or multidrug-resistant tuberculosis (TB). The novel technique described in this article uses a unique surrogate nucleic acid marker produced by phage that infects M. tuberculosis to record phenotypic antibiotic susceptibility in less than a day.
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88
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McIntosh EDG. Efflux: how bacteria use pumps to control their microenvironment. Handb Exp Pharmacol 2012:153-166. [PMID: 23090601 DOI: 10.1007/978-3-642-28951-4_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Efflux pumps are a potent and clinically important cause of antibiotic resistance. The particular focus of this chapter is on the efflux pump as a target for antimicrobial therapy and the development of new antibacterials to address the efflux problem.Tigecycline is an example of how old antibiotics, in this case tetracyclines, which have become substrates for efflux pumps, can be extensively modified to restore antimicrobial activity and clinical efficacy.
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89
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Sirgel FA, Warren RM, Streicher EM, Victor TC, van Helden PD, Böttger EC. embB306 Mutations as Molecular Indicators to Predict Ethambutol Susceptibility inMycobacterium tuberculosis. Chemotherapy 2012; 58:358-63. [DOI: 10.1159/000343474] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 09/13/2012] [Indexed: 11/19/2022]
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90
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Ethambutol pharmacokinetic variability is linked to body mass in overweight, obese, and extremely obese people. Antimicrob Agents Chemother 2011; 56:1502-7. [PMID: 22155817 DOI: 10.1128/aac.05623-11] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We conducted a prospective study of 18 adult volunteers (male-to-female ratio of 1) whose body mass index fell into categories of <25, 25 to 40, or >40 kg/m(2), who received a single oral dose of 1,600 mg ethambutol. Only individuals with normal renal function were recruited. The minimum body mass (M) was 45.6 kg, the median was 90.8 kg, and the maximum weight was 160.4 kg. Ethambutol pharmacokinetics were best described by a two-compartment model. Inclusion of weight as a covariate dramatically improved the model, with a relative likelihood approaching infinity. The typical clearance was 42.6 liters/h. Ethambutol systemic clearance was proportional to (M/45.6)(3/4) and thus obeyed fractal geometry-based laws. This means that the area under the concentration-time curve (AUC) actually decreased for obese patients compared to that for leaner patients, reducing chances of concentration-dependent toxicity. On the other hand, such reduced AUCs could lead to therapy failure. Thus, new and individualized ethambutol dosing regimens need to be designed for obese and extremely obese patients.
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91
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Magis-Escurra C, van den Boogaard J, Ijdema D, Boeree M, Aarnoutse R. Therapeutic drug monitoring in the treatment of tuberculosis patients. Pulm Pharmacol Ther 2011; 25:83-6. [PMID: 22179055 DOI: 10.1016/j.pupt.2011.12.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 11/11/2011] [Accepted: 12/03/2011] [Indexed: 11/16/2022]
Abstract
At the University Centre for Chronic Diseases Dekkerswald, a tertiary tuberculosis (TB) referral hospital in The Netherlands, therapeutic drug monitoring (TDM) is used in patients in case of relapse TB, when there is delayed response to TB treatment, and when abnormal TB drug concentrations are suspected for other reasons. In this article, a case series is presented to illustrate the value of individualized TB drug dosing in four patients with low TB drug concentrations. Increased doses of the TB drugs, especially of rifampicin, resulted in adequate peak plasma concentrations and improved clinical response to treatment in these patients, while no adverse events occurred.
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Affiliation(s)
- Cecile Magis-Escurra
- Radboud University Nijmegen Medical Centre, University Centre for Chronic Diseases Dekkerswald, Nijmeegsebaan 31, 6561 KE Groesbeek, The Netherlands.
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92
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Deshpande D, Gumbo T. Pharmacokinetic/pharmacodynamic-based treatment of disseminated Mycobacterium avium. Future Microbiol 2011; 6:433-9. [PMID: 21526944 DOI: 10.2217/fmb.11.25] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Disseminated Mycobacterium avium complex (MAC) is treated with a macrolide and ethambutol. However, the kill rates are extremely slow so that therapy takes many months to years to achieve and even then more than 40% of patients are not completely cured. Recent studies have demonstrated that assays that detect extracellular MAC have a limited predictive value. Antibiotics kill at a much slower and more disappointing rate against bacilli within macrophages. Use of pharmacodynamic/pharmacokinetic models has resulted in design of new doses and dosing schedules for disseminated MAC, as well as new susceptibility breakpoints for ethambutol and moxifloxacin.
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Affiliation(s)
- Devyani Deshpande
- Division of Infectious Diseases, UT Southwestern Medical Center, Dallas, TX 75390-9113, USA
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93
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Plasma drug activity assay for treatment optimization in tuberculosis patients. Antimicrob Agents Chemother 2011; 55:5819-25. [PMID: 21968363 DOI: 10.1128/aac.05561-11] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Low antituberculosis (TB) drug levels are common, but their clinical significance remains unclear, and methods of measurement are resource intensive. Subjects initiating treatment for sputum smear-positive pulmonary TB were enrolled from Kibong'oto National TB Hospital, Tanzania, and levels of isoniazid, rifampin, ethambutol, and pyrazinamide were measured at the time of typical peak plasma concentration (C(2 h)). To evaluate the significance of the effect of observed drug levels on Mycobacterium tuberculosis growth, a plasma TB drug activity (TDA) assay was developed using the Bactec MGIT system. Time to detection of plasma-cocultured M. tuberculosis versus time to detection of control growth was defined as a TDA ratio. TDA assays were later performed using the subject's own M. tuberculosis isolate and C(2 h) plasma from the Tanzanian cohort and compared to drug levels and clinical outcomes. Sixteen subjects with a mean age of 37.8 years ± 10.7 were enrolled. Fourteen (88%) had C(2 h) rifampin levels and 11 (69%) had isoniazid levels below 90% of the lower limit of the expected range. Plasma spiked with various concentrations of antituberculosis medications found TDA assay results to be unaffected by ethambutol or pyrazinamide. Yet with a range of isoniazid and rifampin concentrations, TDA exhibited a statistically significant correlation with drug level and drug MIC, and a TDA of ~1.0 indicated the presence of multidrug-resistant TB. In Tanzania, low (≤ 2.0) TDA was significantly associated with both lower isoniazid and rifampin C(2 h) levels, and very low (≤ 1.5) TDA corresponded to a trend toward lack of cure. Study of TDA compared to additional clinical outcomes and as a therapeutic management tool is warranted.
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94
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Characterization of mutations conferring extensive drug resistance to Mycobacterium tuberculosis isolates in Pakistan. Antimicrob Agents Chemother 2011; 55:5654-9. [PMID: 21911575 DOI: 10.1128/aac.05101-11] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The increasing incidence of extensively drug-resistant (XDR) Mycobacterium tuberculosis in high-tuberculosis-burden countries further highlights the need for improved rapid diagnostic assays. An increasing incidence of XDR M. tuberculosis strains in Pakistan has been reported, but drug resistance-associated mutations in these strains have not been evaluated previously. We sequenced the "hot-spot" regions of rpoB, katG, inhA, ahpC, gyrA, gyrB, and rrs genes in 50 XDR M. tuberculosis strains. It was observed that 2% of rifampin, 6% of isoniazid, 24% of fluoroquinolone, and 32% of aminoglycoside/capreomycin resistance in XDR M. tuberculosis strains would be undetected if only these common hot-spot regions were tested. The frequencies of resistance-conferring mutations were found to be comparable among all XDR M. tuberculosis strain families present, including the Central Asian Strain, Beijing, and East African Indian genogroups and the Unique isolates. Additional genetic loci need to be tested for detection of mutations conferring fluoroquinolone, aminoglycoside, and capreomycin resistance in order to improve molecular diagnosis of regional XDR M. tuberculosis strains.
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95
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Pasipanodya JG, Gumbo T. A new evolutionary and pharmacokinetic-pharmacodynamic scenario for rapid emergence of resistance to single and multiple anti-tuberculosis drugs. Curr Opin Pharmacol 2011; 11:457-63. [PMID: 21807559 DOI: 10.1016/j.coph.2011.07.001] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2011] [Revised: 06/29/2011] [Accepted: 07/01/2011] [Indexed: 12/14/2022]
Abstract
The current understanding of the mechanism of anti-tuberculosis drug resistance has been shaped by the history of development of anti-tuberculosis drugs in the past 60 years and was arrived at as part of inductive generalization. Recently, these standard beliefs have been tested in controlled hollow fiber systems experiments. Drug resistance in Mycobacterium tuberculosis was shown to be related to pharmacokinetic-pharmacodynamic (PK/PD) factors, and factors such as pharmacokinetic variability. Poor PK/PD exposures owing to our current non-optimized dosing regimens initiate a chain of evolution driven events, starting with induction of multi-drug efflux pumps, followed by the development of chromosomal mutations in time, which together lead to high level resistance multi-drug resistant tuberculosis and extremely drug resistant tuberculosis.
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Affiliation(s)
- Jotam G Pasipanodya
- Department of Medicine, UT Southwestern Medical Center, Dallas, TX 75390-9113, USA
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96
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In vitro pharmacokinetic/pharmacodynamic models in anti-infective drug development: focus on TB. Future Med Chem 2011; 2:1355-69. [PMID: 21359155 DOI: 10.4155/fmc.10.224] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
For rapid anti-tuberculosis (TB) drug development in vitro pharmacokinetic/pharmacodynamic (PK/PD) models are useful in evaluating the direct interaction between the drug and the bacteria, thereby guiding the selection of candidate compounds and the optimization of their dosing regimens. Utilizing in vivo drug-clearance profiles from animal and/or human studies and simulating them in an in vitro PK/PD model allows the in-depth characterization of antibiotic activity of new and existing antibacterials by generating time–kill data. These data capture the dynamic interplay between mycobacterial growth and changing drug concentration as encountered during prolonged drug therapy. This review focuses on important PK/PD parameters relevant to anti-TB drug development, provides an overview of in vitro PK/PD models used to evaluate the efficacy of agents against mycobacteria and discusses the related mathematical modeling approaches of time–kill data. Overall, it provides an introduction to in vitro PK/PD models and their application as critical tools in evaluating anti-TB drugs.
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97
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Louw GE, Warren RM, van Pittius NCG, Leon R, Jimenez A, Hernandez-Pando R, McEvoy CRE, Grobbelaar M, Murray M, van Helden PD, Victor TC. Rifampicin reduces susceptibility to ofloxacin in rifampicin-resistant Mycobacterium tuberculosis through efflux. Am J Respir Crit Care Med 2011; 184:269-76. [PMID: 21512166 PMCID: PMC3698754 DOI: 10.1164/rccm.201011-1924oc] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Central dogma suggests that rifampicin resistance in Mycobacterium tuberculosis develops solely through rpoB gene mutations. OBJECTIVE To determine whether rifampicin induces efflux pumps activation in rifampicin resistant M. tuberculosis strains thereby defining rifampicin resistance levels and reducing ofloxacin susceptibility. METHODS Rifampicin and/or ofloxacin minimum inhibitory concentrations (MICs) were determined in rifampicin resistant strains by culture in BACTEC 12B medium. Verapamil and reserpine were included to determine their effect on rifampicin and ofloxacin susceptibility. RT-qPCR was applied to assess expression of efflux pump/transporter genes after rifampicin exposure. To determine whether verapamil could restore susceptibility to first-line drugs, BALB/c mice were infected with a MDR-TB strain and treated with first-line drugs with/without verapamil. MEASUREMENTS AND MAIN FINDINGS Rifampicin MICs varied independently of rpoB mutation and genetic background. Addition reserpine and verapamil significantly restored rifampicin susceptibility (p = 0.0000). RT-qPCR demonstrated that rifampicin induced differential expression of efflux/transporter genes in MDR-TB isolates. Incubation of rifampicin mono-resistant strains in rifampicin (2 μg/ml) for 7 days induced ofloxacin resistance (MIC > 2 μg/ml) in strains with an rpoB531 mutation. Ofloxacin susceptibility was restored by exposure to efflux pump inhibitors. Studies in BALB/c mice showed that verapamil in combination with first-line drugs significantly reduced pulmonary CFUs after 1 and 2 months treatment (p < 0.05). CONCLUSION Exposure of rifampicin resistant M. tuberculosis strains to rifampicin can potentially compromise the efficacy of the second-line treatment regimens containing ofloxacin, thereby emphasising the need for rapid diagnostics to guide treatment. Efflux pump inhibitors have the potential to improve the efficacy of anti-tuberculosis drug treatment.
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Affiliation(s)
- 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, Department of Biomedical Sciences, Faculty of Health Sciences, Stellenbosch University, Cape Town, 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, Department of Biomedical Sciences, Faculty of Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Nicolaas C. Gey van Pittius
- DST/NRF Centre of Excellence for Biomedical Tuberculosis Research/MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, Faculty of Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Rosalba Leon
- Medical Research Unit of Natural Products Pharmacology, Pediatrics Hospital, National Medical Centre, Mexico City, Mexico
| | - Adelina Jimenez
- Medical Research Unit of Natural Products Pharmacology, Pediatrics Hospital, National Medical Centre, Mexico City, Mexico
| | - Rogelio Hernandez-Pando
- Experimental Pathology Section, Department of Pathology, National Institute of Medical Sciences and Nutrition, Mexico City, Mexico
| | - Christopher R. E. McEvoy
- DST/NRF Centre of Excellence for Biomedical Tuberculosis Research/MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, Faculty of Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Melanie Grobbelaar
- DST/NRF Centre of Excellence for Biomedical Tuberculosis Research/MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, Faculty of Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Megan Murray
- Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts
| | - 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, Department of Biomedical Sciences, Faculty of Health Sciences, Stellenbosch University, Cape Town, 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, Department of Biomedical Sciences, Faculty of Health Sciences, Stellenbosch University, Cape Town, South Africa
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98
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Lougheed KE, Osborne SA, Saxty B, Whalley D, Chapman T, Bouloc N, Chugh J, Nott TJ, Patel D, Spivey VL, Kettleborough CA, Bryans JS, Taylor DL, Smerdon SJ, Buxton RS. Effective inhibitors of the essential kinase PknB and their potential as anti-mycobacterial agents. Tuberculosis (Edinb) 2011; 91:277-86. [PMID: 21482481 PMCID: PMC3158675 DOI: 10.1016/j.tube.2011.03.005] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Revised: 03/03/2011] [Accepted: 03/15/2011] [Indexed: 01/18/2023]
Abstract
PknB is an essential serine/threonine kinase of Mycobacterium tuberculosis with possible roles in a number of signalling pathways involved in cell division and metabolism. We screened a library of >50,000 compounds for inhibitors of the in vitro phosphorylation of GarA (Rv1827) by PknB and identified a number of inhibitors. A program of synthetic medicinal chemistry was subsequently conducted around one class of inhibitors and was successful in generating ATP competitive inhibitors with potency in the nanomolar range. Compounds in this class showed cross-reactivity with the related M. tuberculosis kinase, PknF, but not with PknG in an in vitro autophosphorylation assay. These synthesised inhibitors were able to prevent the growth of M. tuberculosis in an Alamar blue assay and in an intracellular model of infection, but only in the micromolar range. We attempted to determine if cell wall permeability was an explanation for the discrepancy between the potent in vitro compared with relatively poor in vivo activity, but found no evidence that the activity of the inhibitors could be improved by weakening the cell wall. Despite a number of drug discovery efforts attempting to develop inhibitors against PknB, it is yet to be reported that any such inhibitors prevent mycobacterial growth at submicromolar concentrations.
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Affiliation(s)
- Kathryn E.A. Lougheed
- Division of Mycobacterial Research, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London, NW7 1AA, United Kingdom
| | - Simon A. Osborne
- Centre for Therapeutics Discovery, MRC Technology, 1-3 Burtonhole Lane, Mill Hill, London, NW7 1AD, United Kingdom
| | - Barbara Saxty
- Centre for Therapeutics Discovery, MRC Technology, 1-3 Burtonhole Lane, Mill Hill, London, NW7 1AD, United Kingdom
| | - David Whalley
- Centre for Therapeutics Discovery, MRC Technology, 1-3 Burtonhole Lane, Mill Hill, London, NW7 1AD, United Kingdom
| | - Tim Chapman
- Centre for Therapeutics Discovery, MRC Technology, 1-3 Burtonhole Lane, Mill Hill, London, NW7 1AD, United Kingdom
| | - Nathalie Bouloc
- Centre for Therapeutics Discovery, MRC Technology, 1-3 Burtonhole Lane, Mill Hill, London, NW7 1AD, United Kingdom
| | - Jasveen Chugh
- Centre for Therapeutics Discovery, MRC Technology, 1-3 Burtonhole Lane, Mill Hill, London, NW7 1AD, United Kingdom
| | - Timothy J. Nott
- Division of Molecular Structure, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London, NW7 1AA, United Kingdom
| | - Dony Patel
- Division of Molecular Structure, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London, NW7 1AA, United Kingdom
| | - Vicky L. Spivey
- Division of Mycobacterial Research, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London, NW7 1AA, United Kingdom
| | - Catherine A. Kettleborough
- Centre for Therapeutics Discovery, MRC Technology, 1-3 Burtonhole Lane, Mill Hill, London, NW7 1AD, United Kingdom
| | - Justin S. Bryans
- Centre for Therapeutics Discovery, MRC Technology, 1-3 Burtonhole Lane, Mill Hill, London, NW7 1AD, United Kingdom
| | - Debra L. Taylor
- Centre for Therapeutics Discovery, MRC Technology, 1-3 Burtonhole Lane, Mill Hill, London, NW7 1AD, United Kingdom
| | - Stephen J. Smerdon
- Division of Molecular Structure, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London, NW7 1AA, United Kingdom
| | - Roger S. Buxton
- Division of Mycobacterial Research, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London, NW7 1AA, United Kingdom
- Corresponding author. Tel.: +44 20 8816 2225; fax: +44 20 8906 4477.
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99
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van den Boogaard J, Boeree MJ, Kibiki GS, Aarnoutse RE. The complexity of the adherence-response relationship in tuberculosis treatment: why are we still in the dark and how can we get out? Trop Med Int Health 2011; 16:693-8. [DOI: 10.1111/j.1365-3156.2011.02755.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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100
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Pasipanodya J, Gumbo T. An oracle: antituberculosis pharmacokinetics-pharmacodynamics, clinical correlation, and clinical trial simulations to predict the future. Antimicrob Agents Chemother 2011; 55:24-34. [PMID: 20937778 PMCID: PMC3019641 DOI: 10.1128/aac.00749-10] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Antimicrobial pharmacokinetic-pharmacodynamic (PK/PD) science and clinical trial simulations have not been adequately applied to the design of doses and dose schedules of antituberculosis regimens because many researchers are skeptical about their clinical applicability. We compared findings of preclinical PK/PD studies of current first-line antituberculosis drugs to findings from several clinical publications that included microbiologic outcome and pharmacokinetic data or had a dose-scheduling design. Without exception, the antimicrobial PK/PD parameters linked to optimal effect were similar in preclinical models and in tuberculosis patients. Thus, exposure-effect relationships derived in the preclinical models can be used in the design of optimal antituberculosis doses, by incorporating population pharmacokinetics of the drugs and MIC distributions in Monte Carlo simulations. When this has been performed, doses and dose schedules of rifampin, isoniazid, pyrazinamide, and moxifloxacin with the potential to shorten antituberculosis therapy have been identified. In addition, different susceptibility breakpoints than those in current use have been identified. These steps outline a more rational approach than that of current methods for designing regimens and predicting outcome so that both new and older antituberculosis agents can shorten therapy duration.
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Affiliation(s)
- Jotam Pasipanodya
- Division of Infectious Diseases, UT Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd., Dallas, Texas 75390-9113
| | - Tawanda Gumbo
- Division of Infectious Diseases, UT Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd., Dallas, Texas 75390-9113
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