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Paleckyte A, Dissanayake O, Mpagama S, Lipman MC, McHugh TD. Reducing the risk of tuberculosis transmission for HCWs in high incidence settings. Antimicrob Resist Infect Control 2021; 10:106. [PMID: 34281623 PMCID: PMC8287104 DOI: 10.1186/s13756-021-00975-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 07/06/2021] [Indexed: 11/10/2022] Open
Abstract
Globally, tuberculosis (TB) is a leading cause of death from a single infectious agent. Healthcare workers (HCWs) are at increased risk of hospital-acquired TB infection due to persistent exposure to Mycobacterium tuberculosis (Mtb) in healthcare settings. The World Health Organization (WHO) has developed an international system of infection prevention and control (IPC) interventions to interrupt the cycle of nosocomial TB transmission. The guidelines on TB IPC have proposed a comprehensive hierarchy of three core practices, comprising: administrative controls, environmental controls, and personal respiratory protection. However, the implementation of most recommendations goes beyond minimal physical and organisational requirements and thus cannot be appropriately introduced in resource-constrained settings and areas of high TB incidence. In many low- and middle-income countries (LMICs) the lack of knowledge, expertise and practice on TB IPC is a major barrier to the implementation of essential interventions. HCWs often underestimate the risk of airborne Mtb dissemination during tidal breathing. The lack of required expertise and funding to design, install and maintain the environmental control systems can lead to inadequate dilution of infectious particles in the air, and in turn, increase the risk of TB dissemination. Insufficient supply of particulate respirators and lack of direction on the re-use of respiratory protection is associated with unsafe working practices and increased risk of TB transmission between patients and HCWs. Delayed diagnosis and initiation of treatment are commonly influenced by the effectiveness of healthcare systems to identify TB patients, and the availability of rapid molecular diagnostic tools. Failure to recognise resistance to first-line drugs contributes to the emergence of drug-resistant Mtb strains, including multidrug-resistant and extensively drug-resistant Mtb. Future guideline development must consider the social, economic, cultural and climatic conditions to ensure that recommended control measures can be implemented in not only high-income countries, but more importantly low-income, high TB burden settings. Urgent action and more ambitious investments are needed at both regional and national levels to get back on track to reach the global TB targets, especially in the context of the COVID-19 pandemic.
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Affiliation(s)
- Ana Paleckyte
- UCL Centre for Clinical Microbiology, Division of Infection & Immunity, UCL, London, UK
| | | | - Stella Mpagama
- Kibong'oto Infectious Diseases Hospital, Kilimanjaro, Tanzania
| | - Marc C Lipman
- UCL Respiratory, Division of Medicine, UCL, London, UK
| | - Timothy D McHugh
- UCL Centre for Clinical Microbiology, Division of Infection & Immunity, UCL, London, UK.
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2
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Wibberg D, Price-Carter M, Rückert C, Blom J, Möbius P. Complete Genome Sequence of Ovine Mycobacterium avium subsp. paratuberculosis Strain JIII-386 (MAP-S/type III) and Its Comparison to MAP-S/type I, MAP-C, and M. avium Complex Genomes. Microorganisms 2020; 9:microorganisms9010070. [PMID: 33383865 PMCID: PMC7823733 DOI: 10.3390/microorganisms9010070] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 12/21/2020] [Accepted: 12/24/2020] [Indexed: 02/07/2023] Open
Abstract
Mycobacterium avium (M. a.) subsp. paratuberculosis (MAP) is a worldwide-distributed obligate pathogen in ruminants causing Johne’s disease. Due to a lack of complete subtype III genome sequences, there is not yet conclusive information about genetic differences between strains of cattle (MAP-C, type II) and sheep (MAP-S) type, and especially between MAP-S subtypes I, and III. Here we present the complete, circular genome of MAP-S/type III strain JIII-386 (DE) closed by Nanopore-technology and its comparison with MAP-S/type I closed genome of strain Telford (AUS), MAP-S/type III draft genome of strain S397 (U.S.), twelve closed MAP-C strains, and eight closed M.-a.-complex-strains. Structural comparative alignments revealed clearly the mosaic nature of MAP, emphasized differences between the subtypes and the higher diversity of MAP-S genomes. The comparison of various genomic elements including transposases and genomic islands provide new insights in MAP genomics. MAP type specific phenotypic features may be attributed to genes of known large sequence polymorphisms (LSPSs) regions I–IV and deletions #1 and #2, confirmed here, but could also result from identified frameshifts or interruptions of various virulence-associated genes (e.g., mbtC in MAP-S). Comprehensive core and pan genome analysis uncovered unique genes (e.g., cytochromes) and genes probably acquired by horizontal gene transfer in different MAP-types and subtypes, but also emphasized the highly conserved and close relationship, and the complex evolution of M.-a.-strains.
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Affiliation(s)
- Daniel Wibberg
- Center for Biotechnology (CeBiTec), Bielefeld University, 33501 Bielefeld, Germany; (D.W.); (C.R.)
| | - Marian Price-Carter
- AgResearch, Hopkirk Research Institute, Grasslands Research Centre, Palmerston North 4442, New Zealand;
| | - Christian Rückert
- Center for Biotechnology (CeBiTec), Bielefeld University, 33501 Bielefeld, Germany; (D.W.); (C.R.)
| | - Jochen Blom
- Bioinformatics and Systems Biology, Justus Liebig University Gießen, D-35390 Gießen, Germany;
| | - Petra Möbius
- Friedrich-Loeffler-Institut/Federal Research Institute for Animal Health, Institute of Molecular Pathogenesis, 07743 Jena, Germany
- Correspondence: ; Tel.: +49-(0)3641-8042280
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Narang A, Garima K, Porwal S, Bhandekar A, Shrivastava K, Giri A, Sharma NK, Bose M, Varma-Basil M. Potential impact of efflux pump genes in mediating rifampicin resistance in clinical isolates of Mycobacterium tuberculosis from India. PLoS One 2019; 14:e0223163. [PMID: 31557231 PMCID: PMC6762166 DOI: 10.1371/journal.pone.0223163] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 09/12/2019] [Indexed: 01/16/2023] Open
Abstract
Despite the consideration of chromosomal mutations as the major cause of rifampicin (RIF) resistance in M. tuberculosis, the role of other mechanisms such as efflux pumps cannot be ruled out. We evaluated the role of four efflux pumps viz., MmpL2 (Rv0507), MmpL5 (Rv0676c), Rv0194 and Rv1250 in providing RIF resistance in M. tuberculosis. The real time expression of the efflux pumps was analyzed in 16 RIF resistant and 11 RIF susceptible clinical isolates of M. tuberculosis after exposure to RIF. Expression of efflux pumps in these isolates was also correlated with mutations in the rpoB gene and MICs of RIF in the presence and absence of efflux pump inhibitors. Under RIF stress, Rv0194 was induced in 8/16 (50%) RIF resistant and 2/11 (18%) RIF susceptible isolates; mmpL5 in 7/16 (44%) RIF resistant and 1/11 (9%) RIF susceptible isolates; Rv1250 in 4/16 (25%) RIF resistant and 2/11 (18%) RIF susceptible isolates; and mmpL2 was upregulated in 2/16 (12.5%) RIF resistant and 1/11 (9%) RIF susceptible isolates. This preliminary study did not find any association between Rv0194, MmpL2, MmpL5 and Rv1250 and RIF resistance. However, the overexpression of Rv0194 and mmpL5 in greater number of RIF resistant isolates as compared to RIF susceptible isolates and expression of Rv0194 in wild type (WT) resistant isolates suggests a need for further investigations.
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Affiliation(s)
- Anshika Narang
- Department of Microbiology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India
| | - Kushal Garima
- Department of Microbiology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India
| | - Shraddha Porwal
- Department of Microbiology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India
| | - Archana Bhandekar
- Department of Microbiology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India
| | - Kamal Shrivastava
- Department of Microbiology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India
| | - Astha Giri
- Department of Microbiology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India
| | - Naresh Kumar Sharma
- Department of Microbiology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India
| | - Mridula Bose
- Department of Microbiology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India
| | - Mandira Varma-Basil
- Department of Microbiology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, India
- * E-mail:
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Genetics and roadblocks of drug resistant tuberculosis. INFECTION GENETICS AND EVOLUTION 2018; 72:113-130. [PMID: 30261266 DOI: 10.1016/j.meegid.2018.09.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 09/20/2018] [Accepted: 09/22/2018] [Indexed: 11/22/2022]
Abstract
Considering the extensive evolutionary history of Mycobacterium tuberculosis, anti-Tuberculosis (TB) drug therapy exerts a recent selective pressure. However, in a microorganism devoid of horizontal gene transfer and with a strictly clonal populational structure such as M. tuberculosis the usual, but not sole, path to overcome drug susceptibility is through de novo mutations on a relatively strict set of genes. The possible allelic diversity that can be associated with drug resistance through several mechanisms such as target alteration or target overexpression, will dictate how these genes can become associated with drug resistance. The success demonstrated by this pathogenic microbe in this latter process and its ability to spread is currently one of the major obstacles to an effective TB elimination. This article reviews the action mechanism of the more important anti-TB drugs, including bedaquiline and delamanid, along with new findings on specific resistance mechanisms. With the development, validation and endorsement of new in vitro molecular tests for drug resistance, knowledge on these resistance mechanisms and microevolutionary dynamics leading to the emergence and fixation of drug resistance mutations within the host is highly important. Additionally, the fitness toll imposed by resistance development is also herein discussed together with known compensatory mechanisms. By elucidating the possible mechanisms that enable one strain to reacquire the original fitness levels, it will be theoretically possible to make more informed decisions and develop novel strategies that can force M. tuberculosis microevolutionary trajectory down through a path of decreasing fitness levels.
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Manicheva OA, Dogonadze MZ, Melnikova NN, Vishnevskiy BI, Manichev SA. THE GROWTH RATE PHENOTYPIC PROPERTY OF MYCOBACTERIUM TUBERCULOSIS CLINICAL STRAINS: DEPENDENCE ON TUBERCULOSIS LOCALIZATION, TREATMENT, DRUG SUSCEPTIBILITY. RUSSIAN JOURNAL OF INFECTION AND IMMUNITY 2018. [DOI: 10.15789/2220-7619-2018-2-175-186] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The phenotypic properties of the M. tuberculosis strains obtained from patients with pulmonary or extra-pulmonary tuberculosis are determined by a complex set of factors: the genetic characteristics of the pathogen, its ability to adapt in vivo and in vitro, the influence of the host’s immune system and chemotherapy. The growth rate as the phenotypic property is the most accessible for the study of the host-pathogen relationships at the level of host/strain population interactions. The aim of the study is to assess in vitro of the growth rate of M. tuberculosis strains isolated from patients with pulmonary and extra-pulmonary tuberculosis: untreated and treated (with surgical and non-surgical treatment) and also sensitive and resistant isolates in comparison with the reference strain H37Rv. To estimate the growth rate of 116 clinical isolates we have used the modified method originally developed by von Groll and co-authors: to get the bacteria growth curve the fluorescence intensity of growing strains (with indicator resazurin) has been measured daily for 8 days in 96- well plate. The growth rate is determined as the slope of the growth curve. The mean values of the growth rate have been calculated in the following groups of patients: 1 — untreated patients with pulmonary tuberculosis (PT), respiratory material; 2 — non-surgical treated PT patients, respiratory material; 3 — surgical treated PT patients (mainly with chronic and hyperchronic process), respiratory material; 4 — patients like in 3rd group, surgical material; 5 — bone and joint tuberculosis (BJT), surgical material. In addition, groups of sensitive and resistant strains have been examined, but there are no significant differences in growth rates. It has been obtained that the growth rate of strains isolated from the PT patients is higher than in BJT patients: it can be explained less favorable conditions for the pathogen vegetation in the BJT. In the case of a closed tuberculous lesion where the pathogen transmission to another host is impossible, then the selection of strains with the property to survive in the tissues of the osteoarticular system is impossible too, therefor it should be observed only an adaptation of the pathogen strain population to the individual host. The growth rate of isolates from untreated PT patients is higher than that of the treated ones. Comparison of the growth parameters of only MDR strains 1–5 groups to eliminate the influence of the sensitivity/resistance has resulted in the same conclusions. We suggest that the decrease in the growth rate of strains from the treated PT patients is in not only result of the treatment, but also is conditioned by adaptation of the pathogen to its external environment, which is the internal environment of the macroorganism. To confirm this assumption, the bacterial load of 1,083 diagnostic specimens grouped in a similar manner has been estimated, taking into account only MDR/XDR strains. In the group of treated patients the frequency of high bacterial load (CFU ≥ 100) reached 52.5–63.8% that shows the conserved fitness of bacteria in such patients. The mean values of the growth rate of the strain H37Rv non-adapted to the macroorganism (due to numerous passages on artificial media) are higher than in all groups of clinical strains. Thus, heterogeneity of phenotypic properties of M. tuberculosis clinical strains on the basis of growth rate has been obtained. The growth rate of M. tuberculosis clinical strains is depended on the tuberculosis localization (PT, BJT) and on the joint effect of patient treatment and pathogen adaptation to the host.
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Satta G, Witney AA, Shorten RJ, Karlikowska M, Lipman M, McHugh TD. Genetic variation in Mycobacterium tuberculosis isolates from a London outbreak associated with isoniazid resistance. BMC Med 2016; 14:117. [PMID: 27530812 PMCID: PMC4988016 DOI: 10.1186/s12916-016-0659-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 07/26/2016] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND The largest outbreak of isoniazid-resistant (INH-R) Mycobacterium tuberculosis in Western Europe is centred in North London, with over 400 cases diagnosed since 1995. In the current study, we evaluated the genetic variation in a subset of clinical samples from the outbreak with the hypothesis that these isolates have unique biological characteristics that have served to prolong the outbreak. METHODS Fitness assays, mutation rate estimation, and whole-genome sequencing were performed to test for selective advantage and compensatory mutations. RESULTS This detailed analysis of the genetic variation of these INH-R samples suggests that this outbreak consists of successful, closely related, circulating strains with heterogeneous resistance profiles and little or no associated fitness cost or impact on their mutation rate. CONCLUSIONS Specific deletions and SNPs could be a peculiar feature of these INH-R M. tuberculosis isolates, and could potentially explain their persistence over the years.
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Affiliation(s)
- Giovanni Satta
- Department of Infection, Centre for Clinical Microbiology, University College London, London, UK. .,Imperial College Healthcare NHS Trust, London, UK.
| | - Adam A Witney
- Institute of Infection and Immunity, St George's, University of London, London, UK
| | - Robert J Shorten
- Department of Infection, Centre for Clinical Microbiology, University College London, London, UK.,Public Health Laboratory Manchester, Manchester Royal Infirmary, Manchester, UK
| | - Magdalena Karlikowska
- Department of Infection, Centre for Clinical Microbiology, University College London, London, UK
| | - Marc Lipman
- Royal Free London NHS Foundation Trust, London, UK.,UCL Respiratory, Division of Medicine, University College London, London, UK
| | - Timothy D McHugh
- Department of Infection, Centre for Clinical Microbiology, University College London, London, UK
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Nguyen L. Antibiotic resistance mechanisms in M. tuberculosis: an update. Arch Toxicol 2016; 90:1585-604. [PMID: 27161440 DOI: 10.1007/s00204-016-1727-6] [Citation(s) in RCA: 125] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 04/27/2016] [Indexed: 12/16/2022]
Abstract
Treatment of tuberculosis (TB) has been a therapeutic challenge because of not only the naturally high resistance level of Mycobacterium tuberculosis to antibiotics but also the newly acquired mutations that confer further resistance. Currently standardized regimens require patients to daily ingest up to four drugs under direct observation of a healthcare worker for a period of 6-9 months. Although they are quite effective in treating drug susceptible TB, these lengthy treatments often lead to patient non-adherence, which catalyzes for the emergence of M. tuberculosis strains that are increasingly resistant to the few available anti-TB drugs. The rapid evolution of M. tuberculosis, from mono-drug-resistant to multiple drug-resistant, extensively drug-resistant and most recently totally drug-resistant strains, is threatening to make TB once again an untreatable disease if new therapeutic options do not soon become available. Here, I discuss the molecular mechanisms by which M. tuberculosis confers its profound resistance to antibiotics. This knowledge may help in developing novel strategies for weakening drug resistance, thus enhancing the potency of available antibiotics against both drug susceptible and resistant M. tuberculosis strains.
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Affiliation(s)
- Liem Nguyen
- Department of Molecular Biology and Microbiology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.
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Meftahi N, Namouchi A, Mhenni B, Brandis G, Hughes D, Mardassi H. Evidence for the critical role of a secondary site rpoB mutation in the compensatory evolution and successful transmission of an MDR tuberculosis outbreak strain. J Antimicrob Chemother 2015; 71:324-32. [PMID: 26538504 DOI: 10.1093/jac/dkv345] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 09/24/2015] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND MDR Mycobacterium tuberculosis clinical strains that cause large outbreaks, particularly among HIV-negative patients, are likely to have undergone the most successful compensatory evolution. Hence, mutations secondary to the acquisition of drug resistance are worthy of consideration in these highly transmissible strains. Here, we assessed the role of a mutation within rpoB, rpoB V615M, secondary to the rifampicin resistance-conferring mutation rpoB S531L, which is associated with a major MDR tuberculosis outbreak strain that evolved in an HIV-negative context in northern Tunisia. METHODS Using BCG as a model organism, we engineered strains harbouring either the rpoB S531L mutation alone or the double mutation rpoB S531L, V615M. Individual and competitive in vitro growth assays were performed in order to assess the relative fitness of each BCG mutant. RESULTS The rpoB V615M mutation was found to be invariably associated with rpoB S531L. Structural analysis mapped rpoB V615M to the same bridge helix region as rpoB compensatory mutations previously described in Salmonella. Compared with the rpoB single-mutant BCG, the double mutant displayed improved growth characteristics and fitness rates equivalent to WT BCG. Strikingly, the rpoB double mutation conferred high-level resistance to rifampicin. CONCLUSIONS Here, we demonstrated the fitness compensatory role of a mutation within rpoB, secondary to the rifampicin resistance mutation rpoB S531L, which is characteristic of an MDR M. tuberculosis major outbreak strain. The finding that this secondary mutation concomitantly increased the resistance level to rifampicin argues for its significant contribution to the successful transmission of the MDR-TB strain.
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Affiliation(s)
- Nedra Meftahi
- Unit of Typing & Genetics of Mycobacteria, Laboratory of Molecular Microbiology, Vaccinology, and Biotechnology Development, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - Amine Namouchi
- Unit of Typing & Genetics of Mycobacteria, Laboratory of Molecular Microbiology, Vaccinology, and Biotechnology Development, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - Besma Mhenni
- Unit of Typing & Genetics of Mycobacteria, Laboratory of Molecular Microbiology, Vaccinology, and Biotechnology Development, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
| | - Gerrit Brandis
- Department of Medical Biochemistry and Microbiology, Box 582 Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Diarmaid Hughes
- Department of Medical Biochemistry and Microbiology, Box 582 Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Helmi Mardassi
- Unit of Typing & Genetics of Mycobacteria, Laboratory of Molecular Microbiology, Vaccinology, and Biotechnology Development, Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, Tunisia
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Chen XH, Zhang BW, Li H, Peng XX. Myo-inositol improves the host's ability to eliminate balofloxacin-resistant Escherichia coli. Sci Rep 2015; 5:10720. [PMID: 26030712 PMCID: PMC5377236 DOI: 10.1038/srep10720] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 04/29/2015] [Indexed: 12/11/2022] Open
Abstract
Antibiotic-resistant mechanisms are associated with fitness costs. However, why antibiotic-resistant bacteria usually show increasing adaptation to hosts is largely unknown, especially from the host's perspective. The present study reveals the host's varied response to balofloxacin-resistant Escherichia coli (BLFX-R) using an integrated proteome and metabolome approach and identifies myo-inositol and phagocytosis-related proteins as crucial biomarkers. Originally, macrophages have an optimal attractive preference to BLFX-S due to more polarization of BLFX-S than BLFX-R, which renders faster elimination to BLFX-S than BLFX-R. The slower elimination to BLFX-R may be reversed by exogenous myo-inositol. Primarily, myo-inositol depolarizes macrophages, elevating adherence to both BLFX-S and BLFX-R. Since the altered adherence is equal to both strains, the myo-inositol-treated macrophages are free of the barrier to BLFX-R and thereby promote phagocytosis of BLFX-R. This work provides a novel strategy based on metabolic modulation for eliminating antibiotic-resistant bacteria with a high degree of host adaptation.
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Affiliation(s)
- Xin-Hai Chen
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, MOE Key Lab Aquat Food Safety, School of Life Sciences, Sun Yat-sen University, University City, Guangzhou 510006, People's Republic of China
| | - Bing-Wen Zhang
- 1] Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, MOE Key Lab Aquat Food Safety, School of Life Sciences, Sun Yat-sen University, University City, Guangzhou 510006, People's Republic of China [2] Drug Discovery Pipeline, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, Guangdong, People's Republic of China
| | - Hui Li
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, MOE Key Lab Aquat Food Safety, School of Life Sciences, Sun Yat-sen University, University City, Guangzhou 510006, People's Republic of China
| | - Xuan-Xian Peng
- Center for Proteomics and Metabolomics, State Key Laboratory of Bio-Control, MOE Key Lab Aquat Food Safety, School of Life Sciences, Sun Yat-sen University, University City, Guangzhou 510006, People's Republic of China
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Ruer S, Pinotsis N, Steadman D, Waksman G, Remaut H. Virulence-targeted Antibacterials: Concept, Promise, and Susceptibility to Resistance Mechanisms. Chem Biol Drug Des 2015; 86:379-99. [DOI: 10.1111/cbdd.12517] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 12/23/2014] [Accepted: 01/06/2015] [Indexed: 12/25/2022]
Affiliation(s)
- Ségolène Ruer
- Structural and Molecular Microbiology; Structural Biology Research Center; VIB; Pleinlaan 2 Brussels 1050 Belgium
- Structural Biology Brussels; Vrije Universiteit Brussel; Pleinlaan 2 Brussels 1050 Belgium
| | - Nikos Pinotsis
- Institute of Structural and Molecular Biology (ISMB); UCL and Birkbeck College; London WC1E 7HX UK
| | - David Steadman
- Wolfson Institute for Biomedical Research (WIBR); UCL; London WC1E 6BT UK
| | - Gabriel Waksman
- Institute of Structural and Molecular Biology (ISMB); UCL and Birkbeck College; London WC1E 7HX UK
| | - Han Remaut
- Structural and Molecular Microbiology; Structural Biology Research Center; VIB; Pleinlaan 2 Brussels 1050 Belgium
- Structural Biology Brussels; Vrije Universiteit Brussel; Pleinlaan 2 Brussels 1050 Belgium
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11
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MacLean RC, Vogwill T. Limits to compensatory adaptation and the persistence of antibiotic resistance in pathogenic bacteria. EVOLUTION MEDICINE AND PUBLIC HEALTH 2014; 2015:4-12. [PMID: 25535278 PMCID: PMC4323496 DOI: 10.1093/emph/eou032] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Antibiotic resistance carries a fitness cost that could potentially limit the spread of resistance in bacterial pathogens. In spite of this cost, a large number of experimental evolution studies have found that resistance is stably maintained in the absence of antibiotics as a result of compensatory evolution. Clinical studies, on the other hand, have found that resistance in pathogen populations usually declines after antibiotic use is stopped, suggesting that compensatory adaptation is not effective in vivo. In this article, we argue that this disagreement arises because there are limits to compensatory adaptation in nature that are not captured by the design of current laboratory selection experiments. First, clinical treatment fails to eradicate antibiotic-sensitive strains, and competition between sensitive and resistant strains leads to the rapid loss of resistance following treatment. Second, laboratory studies overestimate the efficacy of compensatory adaptation in nature by failing to capture costs associated with compensatory mutations. Taken together, these ideas can potentially reconcile evolutionary theory with the clinical dynamics of antibiotic resistance and guide the development of strategies for containing resistance in clinical pathogens.
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Affiliation(s)
- R Craig MacLean
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
| | - Tom Vogwill
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
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12
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Morcillo NS, Imperiale BR, Di Giulio Á, Zumárraga MJ, Takiff H, Cataldi ÁA. Fitness of drug resistant Mycobacterium tuberculosis and the impact on the transmission among household contacts. Tuberculosis (Edinb) 2014; 94:672-7. [DOI: 10.1016/j.tube.2014.08.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 07/05/2014] [Accepted: 08/06/2014] [Indexed: 11/15/2022]
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13
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Koch A, Mizrahi V, Warner DF. The impact of drug resistance on Mycobacterium tuberculosis physiology: what can we learn from rifampicin? Emerg Microbes Infect 2014; 3:e17. [PMID: 26038512 PMCID: PMC3975073 DOI: 10.1038/emi.2014.17] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 12/12/2013] [Accepted: 12/30/2013] [Indexed: 01/08/2023]
Abstract
The emergence of drug-resistant pathogens poses a major threat to public health. Although influenced by multiple factors, high-level resistance is often associated with mutations in target-encoding or related genes. The fitness cost of these mutations is, in turn, a key determinant of the spread of drug-resistant strains. Rifampicin (RIF) is a frontline anti-tuberculosis agent that targets the rpoB-encoded β subunit of the DNA-dependent RNA polymerase (RNAP). In Mycobacterium tuberculosis (Mtb), RIF resistance (RIF(R)) maps to mutations in rpoB that are likely to impact RNAP function and, therefore, the ability of the organism to cause disease. However, while numerous studies have assessed the impact of RIF(R) on key Mtb fitness indicators in vitro, the consequences of rpoB mutations for pathogenesis remain poorly understood. Here, we examine evidence from diverse bacterial systems indicating very specific effects of rpoB polymorphisms on cellular physiology, and consider these observations in the context of Mtb. In addition, we discuss the implications of these findings for the propagation of clinically relevant RIF(R) mutations. While our focus is on RIF, we also highlight results which suggest that drug-independent effects might apply to a broad range of resistance-associated mutations, especially in an obligate pathogen increasingly linked with multidrug resistance.
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Affiliation(s)
- Anastasia Koch
- Medical Research Council/National Health Laboratory Service/University of Cape Town Molecular Mycobacteriology Research Unit, Department of Science and Technology/National Research Foundation Centre of Excellence for Biomedical Tuberculosis Research, Institute of Infectious Disease and Molecular Medicine and Department of Clinical Laboratory Sciences, University of Cape Town , Cape Town 7701, South Africa
| | - Valerie Mizrahi
- Medical Research Council/National Health Laboratory Service/University of Cape Town Molecular Mycobacteriology Research Unit, Department of Science and Technology/National Research Foundation Centre of Excellence for Biomedical Tuberculosis Research, Institute of Infectious Disease and Molecular Medicine and Department of Clinical Laboratory Sciences, University of Cape Town , Cape Town 7701, South Africa
| | - Digby F Warner
- Medical Research Council/National Health Laboratory Service/University of Cape Town Molecular Mycobacteriology Research Unit, Department of Science and Technology/National Research Foundation Centre of Excellence for Biomedical Tuberculosis Research, Institute of Infectious Disease and Molecular Medicine and Department of Clinical Laboratory Sciences, University of Cape Town , Cape Town 7701, South Africa
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14
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A time-to-event pharmacodynamic model describing treatment response in patients with pulmonary tuberculosis using days to positivity in automated liquid mycobacterial culture. Antimicrob Agents Chemother 2012. [PMID: 23183433 DOI: 10.1128/aac.01876-12] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Days to positivity in automated liquid mycobacterial culture have been shown to correlate with mycobacterial load and have been proposed as a useful biomarker for treatment responses in tuberculosis. However, there is currently no quantitative method or model to analyze the change in days to positivity with time on treatment. The objectives of this study were to describe the decline in numbers of mycobacteria in sputum collected once weekly for 8 weeks from patients on treatment for tuberculosis using days to positivity in liquid culture. One hundred forty-four patients with smear-positive pulmonary tuberculosis were recruited from a tuberculosis clinic in Cape Town, South Africa. A nonlinear mixed-effects repeated-time-to-event modeling approach was used to analyze the time-to-positivity data. A biexponential model described the decline in the estimated number of bacteria in patients' sputum samples, while a logistic model with a lag time described the growth of the bacteria in liquid culture. At baseline, the estimated number of rapidly killed bacteria is typically 41 times higher than that of those that are killed slowly. The time to kill half of the rapidly killed bacteria was about 1.8 days, while it was 39 days for slowly killed bacteria. Patients with lung cavitation had higher bacterial loads than patients without lung cavitation. The model successfully described the increase in days to positivity as treatment progressed, differentiating between bacteria that are killed rapidly and those that are killed slowly. Our model can be used to analyze similar data from studies testing new drug regimens.
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15
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Sergeev R, Colijn C, Murray M, Cohen T. Modeling the dynamic relationship between HIV and the risk of drug-resistant tuberculosis. Sci Transl Med 2012; 4:135ra67. [PMID: 22623743 PMCID: PMC3387814 DOI: 10.1126/scitranslmed.3003815] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The emergence of highly drug-resistant tuberculosis (TB) and interactions between TB and HIV epidemics pose serious challenges for TB control. Previous researchers have presented several hypotheses for why HIV-coinfected TB patients may suffer an increased risk of drug-resistant TB (DRTB) compared to other TB patients. Although some studies have found a positive association between an individual's HIV status and his or her subsequent risk of multidrug-resistant TB (MDRTB), the observed individual-level relationship between HIV and DRTB varies substantially among settings. Here, we develop a modeling framework to explore the effect of HIV on the dynamics of DRTB. The model captures the acquisition of resistance to important classes of TB drugs, imposes fitness costs associated with resistance-conferring mutations, and allows for subsequent restoration of fitness because of compensatory mutations. Despite uncertainty in several key parameters, we demonstrate epidemic behavior that is robust over a range of assumptions. Whereas HIV facilitates the emergence of MDRTB within a community over several decades, HIV-seropositive individuals presenting with TB may, counterintuitively, be at lower risk of drug-resistant TB at early stages of the co-epidemic. This situation arises because many individuals with incident HIV infection will already harbor latent Mycobacterium tuberculosis infection acquired at an earlier time when drug resistance was less prevalent. We find that the rise of HIV can increase the prevalence of MDRTB within populations even as it lowers the average fitness of circulating MDRTB strains compared to similar populations unaffected by HIV. Preferential social mixing among individuals with similar HIV status and lower average CD4 counts among HIV-seropositive individuals further increase the expected burden of MDRTB. This model suggests that the individual-level association between HIV and drug-resistant forms of TB is dynamic, and therefore, cross-sectional studies that do not report a positive individual-level association will not provide assurance that HIV does not exacerbate the burden of resistant TB in the community.
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Affiliation(s)
- Rinat Sergeev
- Department of Medicine, Brigham and Women's Hospital, 641 Huntington Ave, 02115, Boston, MA, USA
- Department of Microelectronics, Ioffe Institute, 26 Polytekhnicheskaya, St Petersburg 194021, Russia
| | - Caroline Colijn
- Department of Mathematics, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Megan Murray
- Department of Medicine, Brigham and Women's Hospital, 641 Huntington Ave, 02115, Boston, MA, USA
- Department of Epidemiology, Harvard School of Public Health, 641 Huntington Ave, 02115, Boston, MA, USA
| | - Ted Cohen
- Department of Medicine, Brigham and Women's Hospital, 641 Huntington Ave, 02115, Boston, MA, USA
- Department of Epidemiology, Harvard School of Public Health, 641 Huntington Ave, 02115, Boston, MA, USA
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16
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Smith T, Wolff KA, Nguyen L. Molecular biology of drug resistance in Mycobacterium tuberculosis. Curr Top Microbiol Immunol 2012. [PMID: 23179675 DOI: 10.1007/82_2012_279] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Tuberculosis (TB) has become a curable disease, thanks to the discovery of antibiotics. However, it has remained one of the most difficult infections to treat. Most current TB regimens consist of 6-9 months of daily doses of four drugs that are highly toxic to patients. The purpose of these lengthy treatments is to completely eradicate Mycobacterium tuberculosis, notorious for its ability to resist most antibacterial agents, thereby preventing the formation of drug resistant mutants. On the contrary, the prolonged therapies have led to poor patient adherence. This, together with a severe limit of drug choices, has resulted in the emergence of strains that are increasingly resistant to the few available antibiotics. Here, we review our current understanding of molecular mechanisms underlying the profound drug resistance of M. tuberculosis. This knowledge is essential for the development of more effective antibiotics, which are not only potent against drug resistant M. tuberculosis strains but also help shorten the current treatment courses required for drug susceptible TB.
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Affiliation(s)
- Tasha Smith
- Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
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17
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Rey-Jurado E, Tudó G, Borrell S, Alcaide F, Coll P, Español M, Martín-Casabona N, Mick V, Montemayor M, Moure R, Salvadó M, Vicente E, González-Martín J. Impaired fitness of Mycobacterium tuberculosis resistant isolates in a cell culture model of murine macrophages. J Antimicrob Chemother 2011; 66:2277-80. [PMID: 21791442 DOI: 10.1093/jac/dkr288] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES We analysed the ability of Mycobacterium tuberculosis clinical isolates to penetrate and grow inside murine macrophages as a surrogate of fitness. METHODS Thirty-five drug-resistant and 10 drug-susceptible M. tuberculosis isolates were studied in a murine macrophage model from the J774.2 cell line in a 6 day protocol, performing semi-quantitative counts in Middlebrook 7H11 medium. The mycobacterial penetration index (MPI) after infection and the mycobacterial growth ratio (MGR) inside the macrophages were determined to evaluate the fitness of isolates. RESULTS Isolates with the katG S315T mutation and multidrug-resistant (MDR) isolates had a significantly lower MGR compared with drug-susceptible isolates. The MPI of the isolates with the katG S315T mutation showed a significant decrease compared with the MPI of those without this mutation. A trend to significantly lower values was also observed on comparing the MPI of the MDR isolates with that of the drug-susceptible isolates and the isolates resistant to isoniazid. CONCLUSIONS The isoniazid-resistant and MDR isolates with mutations in the katG gene showed decreased multiplication inside murine macrophages, suggesting a lower fitness of M. tuberculosis with these resistance patterns.
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Affiliation(s)
- Emma Rey-Jurado
- Servei de Microbiologia, CDB, Hospital Clínic de Barcelona-IDIBAPS, Universitat de Barcelona (UB), Barcelona, Spain
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18
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O'Sullivan DM, McHugh TD, Gillespie SH. Mapping the fitness of Mycobacterium tuberculosis strains: a complex picture. J Med Microbiol 2010; 59:1533-1535. [PMID: 20724506 DOI: 10.1099/jmm.0.019091-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- D M O'Sullivan
- Department of Infection, Royal Free Campus, University College London, Rowland Hill Street, Hampstead, London NW3 2PF, UK
| | - T D McHugh
- Department of Infection, Royal Free Campus, University College London, Rowland Hill Street, Hampstead, London NW3 2PF, UK
| | - S H Gillespie
- Health Protection Agency, Regional Microbiology Network, Holborn Gate, London WC1V 7PP, UK.,Department of Infection, Royal Free Campus, University College London, Rowland Hill Street, Hampstead, London NW3 2PF, UK
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19
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Andersson DI, Hughes D. Antibiotic resistance and its cost: is it possible to reverse resistance? Nat Rev Microbiol 2010; 8:260-71. [PMID: 20208551 DOI: 10.1038/nrmicro2319] [Citation(s) in RCA: 1440] [Impact Index Per Article: 102.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Most antibiotic resistance mechanisms are associated with a fitness cost that is typically observed as a reduced bacterial growth rate. The magnitude of this cost is the main biological parameter that influences the rate of development of resistance, the stability of the resistance and the rate at which the resistance might decrease if antibiotic use were reduced. These findings suggest that the fitness costs of resistance will allow susceptible bacteria to outcompete resistant bacteria if the selective pressure from antibiotics is reduced. Unfortunately, the available data suggest that the rate of reversibility will be slow at the community level. Here, we review the factors that influence the fitness costs of antibiotic resistance, the ways by which bacteria can reduce these costs and the possibility of exploiting them.
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Affiliation(s)
- Dan I Andersson
- Department of Medical Biochemistry and Microbiology, Uppsala University, BOX 582, SE-751 23, Uppsala, Sweden.
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20
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Mycobacterium tuberculosis strains with highly discordant rifampin susceptibility test results. J Clin Microbiol 2009; 47:3501-6. [PMID: 19759221 DOI: 10.1128/jcm.01209-09] [Citation(s) in RCA: 144] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The objectives of this study were to investigate the origin of highly discordant rifampin (rifampicin) (RMP) drug susceptibility test results obtained for Mycobacterium tuberculosis strains during proficiency testing. Nine Supra-National Tuberculosis Reference Laboratories tested the RMP susceptibilities of 19 selected M. tuberculosis strains, using standard culture-based methods. The strains were classified as definitely resistant (R) (n = 6) or susceptible (S) (n = 2) or probably resistant (PR) (n = 8) or susceptible (PS) (n = 3) based on rpoB mutations and treatment outcome. All methods yielded a susceptible result for the two S and three PS strains lacking an rpoB mutation and a resistant result for one R strain with a Ser531Leu mutation and one PR strain with a double mutation. Although the remaining 12 R and PR strains had rpoB mutations (four Asp516Tyr, three Leu511Pro, two Leu533Pro, one each His526Leu/Ser, and one Ile572Phe), they were all susceptible by the radiometric Bactec 460TB or Bactec 960 MGIT methods. In contrast, only one was susceptible by the proportion method on Löwenstein-Jensen medium and two on Middlebrook 7H10 agar. Low-level but probably clinically relevant RMP resistance linked to specific rpoB mutations is easily missed by standard growth-based methods, particularly the automated broth-based systems. Further studies are required to confirm these findings, to determine the frequency of these low-level-resistant isolates, and to identify technical improvements that may identify such strains.
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21
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Jassal M, Bishai WR. Extensively drug-resistant tuberculosis. THE LANCET. INFECTIOUS DISEASES 2009; 9:19-30. [DOI: 10.1016/s1473-3099(08)70260-3] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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22
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Jones KDJ, Hesketh T, Yudkin J. Extensively drug-resistant tuberculosis in sub-Saharan Africa: an emerging public-health concern. Trans R Soc Trop Med Hyg 2008; 102:219-24. [PMID: 18243260 DOI: 10.1016/j.trstmh.2007.11.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2007] [Revised: 11/27/2007] [Accepted: 11/27/2007] [Indexed: 11/19/2022] Open
Abstract
The extensively drug-resistant tuberculosis (XDR-TB) categorisation has been developed as a phenotypic description of those TB strains that are resistant to most conventional anti-TB drugs. While widely accepted to have significant incidence in those areas, such as Eastern Europe, that have high levels of multidrug resistance, recent reports have described a cluster of XDR-TB cases in the KwaZulu-Natal province of South Africa. With very high case-fatality rates in this setting and a paucity of potential treatment options, concerns have grown about the possibility of an outbreak of highly lethal TB occurring in areas where TB prevalence, generally, is at its highest. In this article, we review previously documented case series of XDR-TB, and examine questions around the likelihood of rapid XDR-TB expansion in sub-Saharan Africa. We analyse how current TB control measures in the area might cope with such a challenge, and identify new areas for focus within the research and development community.
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Affiliation(s)
- Kelsey D J Jones
- UCL Centre for International Health and Development, The Institute of Child Health, London, UK.
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23
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Abstract
Tuberculosis remains a global public health threat: the causative organism, Mycobacterium tuberculosis, was once thought to show little genetic variation, but research in the last 10 years has demonstrated an ability to change in a series of different time frames. Related species of mycobacteria have undergone evolution by deletion of segments of DNA, allowing Mycobacterium bovis and other species to emerge from the M. tuberculosis complex, disproving the previously accepted theories. Deletions also affect the pathogenic potential of different lineages of M. tuberculosis. Over shorter time periods genetic variation is achieved by the movement of insertion sequences such as IS6110. Some lineages identified by this means are over-represented in patient populations, suggesting a genetic advantage, although the mechanism for this is not yet apparent. M. tuberculosis must also adapt to host and antibiotic selection pressure, and this is achieved by point mutations. Almost all antibiotic resistance emerges in this way, and data from clinical and in vitro studies indicate that M. tuberculosis exists with pre-existent mutants that remain as a small proportion of the population because of fitness deficits. Under certain physiological conditions, these rarer mutants may be favoured and, when antibiotic selection pressure is applied, will rise to dominate the bacterial population. M. tuberculosis is a highly effective pathogen that has caused disease in human populations for millennia. We are now starting to understand some of the genetic mechanisms behind this phenomenon.
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24
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Gay PB, Gillespie SH. Antibiotic resistance markers in genetically modified plants: a risk to human health? THE LANCET. INFECTIOUS DISEASES 2005; 5:637-46. [PMID: 16183518 DOI: 10.1016/s1473-3099(05)70241-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Cotransformation with an antibiotic-resistance marker is often necessary in the process of creating a genetically modified (GM) plant. Concern has been expressed that the release of these markers in GM plants may result in an increase in the rate of antibiotic resistance in human pathogens. For such an event to occur, DNA must not be totally degraded in field conditions, and the antibiotic-resistance marker must encounter potential recipient bacteria and be taken up by them, before being integrated into the bacterial genome, and the genes then expressed. In addition, the new recombinant must overcome the physiological disadvantage of acquisition of a piece of foreign DNA, probably in conditions where the new gene does not provide a selective advantage. We review each of these stages, summarising the investigations that have followed each of these steps. We contrast the potential increase in the antibiotic resistance reservoir created by antibiotic-resistance markers in GM plants with the current situation created by medical antibiotic prescribing. We conclude that, although fragments of DNA large enough to contain an antibiotic-resistance gene may survive in the environment, the barriers to transfer, incorporation, and transmission are so substantial that any contribution to antibiotic resistance made by GM plants must be overwhelmed by the contribution made by antibiotic prescription in clinical practice.
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25
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McHugh TD, Batt SL, Shorten RJ, Gosling RD, Uiso L, Gillespie SH. Mycobacterium tuberculosis lineage: a naming of the parts. Tuberculosis (Edinb) 2005; 85:127-36. [PMID: 15850751 DOI: 10.1016/j.tube.2004.06.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2004] [Revised: 06/03/2004] [Accepted: 06/09/2004] [Indexed: 11/18/2022]
Abstract
There have been many reports of groups of related Mycobacterium tuberculosis strains described variously as lineages, families or clades. There is no objective definition of these groupings, making it impossible to define relationships between those groups with biological advantages. Here we describe two groups of related strains obtained from an epidemiological study in Tanzania, which we define as the Kilimanjaro and Meru lineages on the basis of IS6110 restriction fragment length polymorphism (RFLP), polymorphic GC rich sequence (PGRS) RFLP and mycobacterial interspersed repeat unit (MIRU) typing. We investigated the concordance between each of the typing techniques and the dispersal of the typing profiles from a core pattern. The Meru lineage is more dispersed than the Kilimanjaro lineage and we speculate that the Meru lineage is older. We suggest that this approach provides an objective definition that proves robust in this epidemiological study. Such a framework will permit associations between a lineage and clinical or bacterial phenomenon to be tested objectively. This definition will also enable new putative lineages to be objectively tested.
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Affiliation(s)
- T D McHugh
- Department of Infection, Centre for Medical Microbiology, University College London, Royal Free Campus, Rowland Hill Street, Hampstead, London NW3 2PF, UK.
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26
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Coll P, Aragón LM, Alcaide F, Espasa M, Garrigó M, González J, Manterola JM, Orús P, Salvadó M. Molecular analysis of isoniazid and rifampin resistance in Mycobacterium tuberculosis isolates recovered from Barcelona. Microb Drug Resist 2005; 11:107-14. [PMID: 15910223 DOI: 10.1089/mdr.2005.11.107] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We studied the presence of mutations in the whole katG gene and specific regions of the oxyR-ahpC and mabA-inhA regulatory region in 61 Mycobacterium tuberculosis isoniazid-resistant isolates. An 81-bp region of the rpoB gene was also sequenced in 17 rifampin-resistant strains. Alterations in the katG gene were detected in 55% of the isolates. Mutation in codon 315 was the most prevalent (32%). Strains showed a high level of resistance, and most maintained a substantial catalase-peroxidase activity. Three strains with an isoniazid MIC of >or=32 microg/ml lacked catalase-peroxidase activity. Two of them had deletions in the catalytic domain of the KatG protein. One strain with deletion and three strains with mutations in the C-terminal domain showed low-level resistance and conserved the catalase-peroxidase activity. Mutations in the mabA-inhA regulatory region were identified in 32% of the isolates. All had low-level resistance, and the vast majority conserved catalase-peroxidase activity. Seventeen percent of the isoniazid-resistant isolates had no detectable alterations at the studied loci. Resistance to rifampin was associated with mutations in the 81-bp of the rpoB gene in all cases. IS6110 analysis indicated that recent transmission contributed substantially to the emergence of isoniazid- resistant tuberculosis in Barcelona through short transmission chains. A rapid genotypic assay, including the 315-katG codon and the -15 nucleotide of the mabA-inhA regulatory region, may cover 62% of isoniazid- resistant strains in Barcelona. In contrast, the targeting of the 81-bp region of rpoB would detect all our rifampin-resistant isolates.
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Affiliation(s)
- Pere Coll
- Servei de Microbiología, Hospital de la Santa Creu i Sant Pau, Barcelona.
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27
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Toungoussova OS, Caugant DA, Sandven P, Mariandyshev AO, Bjune G. Impact of drug resistance on fitness of Mycobacterium tuberculosis strains of the W-Beijing genotype. ACTA ACUST UNITED AC 2005; 42:281-90. [PMID: 15477041 DOI: 10.1016/j.femsim.2004.05.012] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2003] [Revised: 04/21/2004] [Accepted: 05/29/2004] [Indexed: 10/26/2022]
Abstract
Mycobacterium tuberculosis strains of the W-Beijing genotype became a common cause of tuberculosis during the past years and they are often associated with drug resistance. The biological factors facilitating the selection and wide dissemination of these strains are not known. To determine how acquisition of drug resistance affected growth of strains of the W-Beijing genotype, the growth of 55 M. tuberculosis isolates were studied using the BBL MGIT Mycobacteria Growth Indicator Tube and the BACTEC MGIT 960 System. Susceptible strains of non-Beijing genotypes were found to be the most fit strains. Drug-resistant strains of non-Beijing genotypes were more likely to grow slower than susceptible strains (P=0.001). Drug-resistant strains of the W-Beijing genotype had two tendencies of growth: some of them showed reduced growth compared to susceptible strains, while others did not show loss of fitness measured as growth.
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Affiliation(s)
- Olga S Toungoussova
- Division of Infectious Disease Control, Norwegian Institute of Public Health, Oslo, Norway.
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28
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Luo N, Pereira S, Sahin O, Lin J, Huang S, Michel L, Zhang Q. Enhanced in vivo fitness of fluoroquinolone-resistant Campylobacter jejuni in the absence of antibiotic selection pressure. Proc Natl Acad Sci U S A 2005; 102:541-6. [PMID: 15634738 PMCID: PMC545549 DOI: 10.1073/pnas.0408966102] [Citation(s) in RCA: 268] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Campylobacter jejuni, a major foodborne human pathogen, has become increasingly resistant to fluoroquinolone (FQ) antimicrobials. By using clonally related isolates and genetically defined mutants, we determined the fitness of FQ-resistant Campylobacter in chicken (a natural host and a major reservoir for C. jejuni) in the absence of antibiotic selection pressure. When monoinoculated into the host, FQ-resistant and FQ-susceptible Campylobacter displayed similar levels of colonization and persistence in the absence of FQ antimicrobials. The prolonged colonization in chickens did not result in loss of the FQ resistance and the resistance-conferring point mutation (C257 --> T) in the gyrA gene. Strikingly, when coinoculated into chickens, the FQ-resistant Campylobacter isolates outcompeted the majority of the FQ-susceptible strains, indicating that the resistant Campylobacter was biologically fit in the chicken host. The fitness advantage was not due to compensatory mutations in the genes targeted by FQ and was linked directly to the single point mutation in gyrA, which confers on Campylobacter a high-level resistance to FQ antimicrobials. In certain genetic backgrounds, the same point mutation entailed a biological cost on Campylobacter, as evidenced by its inability to compete with the FQ-susceptible Campylobacter. These findings provide a previously undescribed demonstration of the profound effect of a resistance-conferring point mutation in gyrA on the fitness of a major foodborne pathogen in its natural host and suggest that the rapid emergence of FQ-resistant Campylobacter on a worldwide scale may be attributable partly to the enhanced fitness of the FQ-resistant isolates.
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Affiliation(s)
- Naidan Luo
- Food Animal Health Research Program, Ohio Agricultural Research and Development Center, Ohio State University, Wooster, OH 44691, USA
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29
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Les épidémies nosocomiales de tuberculoses multirésistantes peuvent se propager dans la communauté, surtout si la durée d’isolement des patients est insuffisante. Rev Mal Respir 2004. [DOI: 10.1016/s0761-8425(04)72030-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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30
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Maisnier-Patin S, Andersson DI. Adaptation to the deleterious effects of antimicrobial drug resistance mutations by compensatory evolution. Res Microbiol 2004; 155:360-9. [PMID: 15207868 DOI: 10.1016/j.resmic.2004.01.019] [Citation(s) in RCA: 186] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2003] [Accepted: 01/20/2004] [Indexed: 11/25/2022]
Abstract
Compensatory mutations, due to their ability to mask the deleterious effects of another mutation, are important for the adaptation and evolution of most organisms. Resistance to antibiotics, antivirals, antifungals, herbicides and insecticides is usually associated with a fitness cost. As a result of compensatory evolution, the initial fitness costs conferred by resistance mutations (or other deleterious mutations) can often be rapidly and efficiently reduced. Such compensatory evolution is potentially of importance for (i) the long-term persistence of drug resistance, (ii) reducing the rate of fitness loss associated with the accumulation of deleterious mutations in small asexual populations, and (iii) the evolution of complexity of cellular processes.
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Affiliation(s)
- Sophie Maisnier-Patin
- Department of Bacteriology, Swedish Institute for Infectious Disease Control, 171 82 Solna, Sweden
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