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Dartois V, Dick T. Therapeutic developments for tuberculosis and nontuberculous mycobacterial lung disease. Nat Rev Drug Discov 2024; 23:381-403. [PMID: 38418662 PMCID: PMC11078618 DOI: 10.1038/s41573-024-00897-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/24/2024] [Indexed: 03/02/2024]
Abstract
Tuberculosis (TB) drug discovery and development has undergone nothing short of a revolution over the past 20 years. Successful public-private partnerships and sustained funding have delivered a much-improved understanding of mycobacterial disease biology and pharmacology and a healthy pipeline that can tolerate inevitable attrition. Preclinical and clinical development has evolved from decade-old concepts to adaptive designs that permit rapid evaluation of regimens that might greatly shorten treatment duration over the next decade. But the past 20 years also saw the rise of a fatal and difficult-to-cure lung disease caused by nontuberculous mycobacteria (NTM), for which the drug development pipeline is nearly empty. Here, we discuss the similarities and differences between TB and NTM lung diseases, compare the preclinical and clinical advances, and identify major knowledge gaps and areas of cross-fertilization. We argue that applying paradigms and networks that have proved successful for TB, from basic research to clinical trials, will help to populate the pipeline and accelerate curative regimen development for NTM disease.
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Affiliation(s)
- Véronique Dartois
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, USA.
- Department of Medical Sciences, Hackensack Meridian School of Medicine, Nutley, NJ, USA.
| | - Thomas Dick
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, NJ, USA
- Department of Medical Sciences, Hackensack Meridian School of Medicine, Nutley, NJ, USA
- Department of Microbiology and Immunology, Georgetown University, Washington, DC, USA
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Ho CH, Chen CJ, Hsieh CY, Su PY. Amino acid substitutions in the region between RpoB clusters II and III on rifampin susceptibility in Haemophilus influenzae. Eur J Clin Microbiol Infect Dis 2023; 42:1499-1509. [PMID: 37906391 DOI: 10.1007/s10096-023-04689-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 10/18/2023] [Indexed: 11/02/2023]
Abstract
BACKGROUND Rifampin is a potent chemoprophylactic antibiotic for Haemophilus influenzae infection, and the resistance rate in H. influenzae is low. In this study, we assessed rifampin resistance-related genetic variations in H. influenzae. METHODS Rifampin susceptibility testing and whole-genome sequencing were performed in 51 H. influenzae isolates. Variations associated with rifampin resistance were identified using Fisher's exact tests. Functional assays were performed to evaluate the effect of RpoB substitutions on rifampin susceptibility. RESULTS Using the genome of the Rd KW20 H. influenzae strain as the reference, we detected 40 genetic variations in rpoB, which resulted in 39 deduced amino acid substitutions among the isolates. Isolate A0586 was resistant to rifampin, with a minimum inhibitory concentration (MIC) = 8 μg/mL. Phylogenetic analyses revealed that the RpoB sequence of isolate A0586 was distinct from other isolates. Five substitutions, including H526N located in cluster I and L623F, R628C, L645F, and L672F in the region between clusters II and III, were unique to isolate A0586. In two rifampin-susceptible H. influenzae isolates, RpoB-H526N alone and in combination with RpoB-L672F increased the MICs of rifampin to 4 and 8 μg/mL, respectively. RpoB-L672F did not affect cell growth and transcription in H. influenzae isolates. No amino acid substitutions in the AcrAB-TolC efflux pump or outer membrane proteins were found to be associated with rifampin resistance in H. influenzae. CONCLUSIONS Our findings indicate that L672F substitution in the region between RpoB clusters II and III has an aggravating effect on rifampin resistance in H. influenzae.
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Affiliation(s)
- Cheng-Hsun Ho
- Department of Medical Laboratory Science, College of Medical Science and Technology, I-Shou University, Kaohsiung, Taiwan.
| | - Chuan-Jung Chen
- Department of Medical Laboratory Science, College of Medical Science and Technology, I-Shou University, Kaohsiung, Taiwan
| | - Chia-Yun Hsieh
- Department of Medical Laboratory Science, College of Medical Science and Technology, I-Shou University, Kaohsiung, Taiwan
| | - Pei-Yi Su
- Department of Laboratory Medicine, E-DA Hospital, Kaohsiung, Taiwan
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Ganapathy US, Lan T, Dartois V, Aldrich CC, Dick T. Blocking ADP-ribosylation expands the anti-mycobacterial spectrum of rifamycins. Microbiol Spectr 2023; 11:e0190023. [PMID: 37681986 PMCID: PMC10580999 DOI: 10.1128/spectrum.01900-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 07/13/2023] [Indexed: 09/09/2023] Open
Abstract
The clinical utility of rifamycins against non-tuberculous mycobacterial (NTM) disease is limited by intrinsic drug resistance achieved by ADP-ribosyltransferase Arr. By blocking the site of ribosylation, we recently optimized a series of analogs with substantially improved potency against Mycobacterium abscessus. Here, we show that a representative member of this series is significantly more potent than rifabutin against major NTM pathogens expressing Arr, providing a powerful medicinal chemistry approach to expand the antimycobacterial spectrum of rifamycins. IMPORTANCE Lung disease caused by a range of different species of non-tuberculous mycobacteria (NTM) is difficult to cure. The rifamycins are very active against Mycobacterium tuberculosis, which causes tuberculosis (TB), but inactive against many NTM species. Previously, we showed that the natural resistance of the NTM Mycobacterium abscessus to rifamycins is due to enzymatic inactivation of the drug by the bacterium. We generated chemically modified versions of rifamycins that prevent inactivation by the bacterium and thus become highly active against M. abscessus. Here, we show that such a chemically modified rifamycin is also highly active against several additional NTM species that harbor the rifamycin inactivating enzyme found in M. abscessus, including M. chelonae, M. fortuitum, and M. simiae. This finding expands the potential therapeutic utility of our novel rifamycins to include several currently difficult-to-cure NTM lung disease pathogens beyond M. abscessus.
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Affiliation(s)
- Uday S. Ganapathy
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey, USA
| | - Tian Lan
- Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota, USA
| | - Véronique Dartois
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey, USA
- Department of Medical Sciences, Hackensack Meridian School of Medicine, Nutley, New Jersey, USA
| | - Courtney C. Aldrich
- Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota, USA
| | - Thomas Dick
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey, USA
- Department of Medical Sciences, Hackensack Meridian School of Medicine, Nutley, New Jersey, USA
- Department of Microbiology and Immunology, Georgetown University, Washington, DC, USA
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Relationship between Resistance to Ethambutol and Rifampin and Clinical Outcomes in Mycobacterium avium Complex Pulmonary Disease. Antimicrob Agents Chemother 2022; 66:e0202721. [PMID: 35266825 DOI: 10.1128/aac.02027-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We evaluated the associations between the in vitro activities of ethambutol and rifampin and clinical outcomes of Mycobacterium avium complex (MAC) pulmonary disease (PD). Among 158 patients with MAC-PD, there was no relationship between high MICs for ethambutol and/or rifampin and treatment failure for MAC-PD. Ethambutol and rifampin resistance was common among MAC isolates (rates of 87% and 59%, respectively), but mutations in embB, rpoB, and rpoC were rare, with detection in only 4% of the drug-resistant MAC isolates.
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Singh P, Jamal S, Ahmed F, Saqib N, Mehra S, Ali W, Roy D, Ehtesham NZ, Hasnain SE. Computational modeling and bioinformatic analyses of functional mutations in drug target genes in Mycobacterium tuberculosis. Comput Struct Biotechnol J 2021; 19:2423-2446. [PMID: 34025934 PMCID: PMC8113780 DOI: 10.1016/j.csbj.2021.04.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 04/09/2021] [Accepted: 04/15/2021] [Indexed: 11/29/2022] Open
Abstract
MycoTRAP-DB, a database of mutations and their impact on normal functionality of protein in M.tb genes. Several secondary mutations were identified with significant impact on protein structure and function. Comprehensive information gives insight for screening of suspected hotspots in advance to combat drug resistant TB.
Tuberculosis (TB) continues to be the leading cause of deaths due to its persistent drug resistance and the consequent ineffectiveness of anti-TB treatment. Recent years witnessed huge amount of sequencing data, revealing mutations responsible for drug resistance. However, the lack of an up-to-date repository remains a barrier towards utilization of these data and identifying major mutations-associated with resistance. Amongst all mutations, non-synonymous mutations alter the amino acid sequence of a protein and have a much greater effect on pathogenicity. Hence, this type of gene mutation is of prime interest of the present study. The purpose of this study is to develop an updated database comprising almost all reported substitutions within the Mycobacterium tuberculosis (M.tb) drug target genes rpoB, inhA, katG, pncA, gyrA and gyrB. Various bioinformatics prediction tools were used to assess the structural and biophysical impacts of the resistance causing non-synonymous single nucleotide polymorphisms (nsSNPs) at the molecular level. This was followed by evaluating the impact of these mutations on binding affinity of the drugs to target proteins. We have developed a comprehensive online resource named MycoTRAP-DB (Mycobacterium tuberculosis Resistance Associated Polymorphisms Database) that connects mutations in genes with their structural, functional and pathogenic implications on protein. This database is accessible at http://139.59.12.92. This integrated platform would enable comprehensive analysis and prioritization of SNPs for the development of improved diagnostics and antimycobacterial medications. Moreover, our study puts forward secondary mutations that can be important for prognostic assessments of drug-resistance mechanism and actionable anti-TB drugs.
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Affiliation(s)
- Pooja Singh
- Jamia Hamdard Institute of Molecular Medicine, Jamia Hamdard, New Delhi 110062, India
| | - Salma Jamal
- Jamia Hamdard Institute of Molecular Medicine, Jamia Hamdard, New Delhi 110062, India
| | - Faraz Ahmed
- Jamia Hamdard Institute of Molecular Medicine, Jamia Hamdard, New Delhi 110062, India
| | - Najumu Saqib
- Jamia Hamdard Institute of Molecular Medicine, Jamia Hamdard, New Delhi 110062, India
| | - Seema Mehra
- Jamia Hamdard Institute of Molecular Medicine, Jamia Hamdard, New Delhi 110062, India
| | - Waseem Ali
- Jamia Hamdard Institute of Molecular Medicine, Jamia Hamdard, New Delhi 110062, India
| | - Deodutta Roy
- Department of Environmental and Occupational Health, Florida International University, Miami 33029, USA
| | - Nasreen Z Ehtesham
- ICMR-National Institute of Pathology, Safdarjung Hospital Campus, New Delhi, India
| | - Seyed E Hasnain
- Department of Life Sciences, School of Basic Sciences and Research, Sharda University, Greater Noida 201301, India.,Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, Delhi (IIT-D), Hauz Khas, New Delhi 110016, India
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Huh HJ, Kim SY, Jhun BW, Shin SJ, Koh WJ. Recent advances in molecular diagnostics and understanding mechanisms of drug resistance in nontuberculous mycobacterial diseases. INFECTION GENETICS AND EVOLUTION 2018; 72:169-182. [PMID: 30315892 DOI: 10.1016/j.meegid.2018.10.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 10/08/2018] [Accepted: 10/09/2018] [Indexed: 01/31/2023]
Abstract
Accumulating evidence suggests that human infections caused by nontuberculous mycobacteria (NTM) are increasing worldwide, indicating that NTM disease is no longer uncommon in many countries. As a result of an increasing emphasis on the importance of differential identification of NTM species, several molecular tools have recently been introduced in clinical and experimental settings. These advances have led to a much better understanding of the diversity of NTM species with regard to clinical aspects and the potential factors responsible for drug resistance that influence the different outcomes of NTM disease. In this paper, we review currently available molecular diagnostics for identification and differentiation of NTM species by summarizing data from recently applied methods, including commercially available assays, and their relevant strengths and weaknesses. We also highlight drug resistance-associated genes in clinically important NTM species. Understanding the basis for different treatment outcomes with different causative species and drug-resistance mechanisms will eventually improve current treatment regimens and facilitate the development of better control measures for NTM diseases.
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Affiliation(s)
- Hee Jae Huh
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Su-Young Kim
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Byung Woo Jhun
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Sung Jae Shin
- Department of Microbiology, Institute for Immunology and Immunological Disease, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, South Korea.
| | - Won-Jung Koh
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
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A balancing act: efflux/influx in mycobacterial drug resistance. Antimicrob Agents Chemother 2009; 53:3181-9. [PMID: 19451293 DOI: 10.1128/aac.01577-08] [Citation(s) in RCA: 172] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Zaczek A, Brzostek A, Augustynowicz-Kopec E, Zwolska Z, Dziadek J. Genetic evaluation of relationship between mutations in rpoB and resistance of Mycobacterium tuberculosis to rifampin. BMC Microbiol 2009; 9:10. [PMID: 19146699 PMCID: PMC2652454 DOI: 10.1186/1471-2180-9-10] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2008] [Accepted: 01/15/2009] [Indexed: 11/12/2022] Open
Abstract
Background Rifampin is a first line antituberculosis drug active against bacilli in logarithmic and stationary phase, which interferes with RNA synthesis by binding to bacterial RNA polymerase. Tubercle bacilli achieve resistance to rifampin by accumulation of mutations in a short-81 bp region of the rpoB gene. Among many mutations identified in the rpoB gene, few were verified by molecular genetic methods as responsible for resistance to rifampin (RMP). Results In this study eight different mutations identified in an 81 bp section of a "hot spot" region of the rpoB gene of RMP resistant Mycobacterium tuberculosis clinical strains were evaluated in respect to drug resistance. It was found that: mutations in positions 526 (H/D), 516 (D/V) and 531 (S/L) result in high level resistance to rifampin; mutations in positions 516 (D/Y), 515 (M/I), 510 (Q/H) or a double mutation in codons 512 (S/I) and 516 (D/G) relate to low level of resistance. Gene rpoB carrying mutations in codon 513 (Q/L) introduced into an M. tuberculosis laboratory strain did not cause resistance to rifampin, however the same gene introduced into two different clinical strains did, with the level of resistance depending on the host strain. Conclusion Mutations in an 81 bp "hot spot" region of the rpoB of M. tuberculosis lead to different levels of resistance to rifampin. Some mutations in this "hot spot" region of rpoB require a specific genetic background for the host strain to develop resistance to rifampin. Therefore, the identification of such mutations in a clinical M. tuberculosis strain is not enough to classify the given strain as resistant to rifampin.
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Affiliation(s)
- Anna Zaczek
- Institute for Medical Biology, Polish Academy of Sciences, Lodz, Poland.
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Wu X, Zhang J, Chao L, Liang J, Lu Y, Li H, Yang Y, Liang Y, Li C. Identification of Rifampin-Resistant Genotypes in Mycobacterium tuberculosis by PCR-Reverse Dot Blot Hybridization. Mol Biotechnol 2008; 41:1-7. [DOI: 10.1007/s12033-008-9085-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2008] [Accepted: 06/19/2008] [Indexed: 10/21/2022]
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Alexander DC, Jones JRW, Liu J. A rifampin-hypersensitive mutant reveals differences between strains of Mycobacterium smegmatis and presence of a novel transposon, IS1623. Antimicrob Agents Chemother 2004; 47:3208-13. [PMID: 14506032 PMCID: PMC201156 DOI: 10.1128/aac.47.10.3208-3213.2003] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rifampin is a front-line antibiotic for the treatment of tuberculosis. Infections caused by rifampin- and multidrug-resistant Mycobacterium tuberculosis strains are difficult to treat and contribute to a poor clinical outcome. Rifampin resistance most often results from mutations in rpoB. However, some drug-resistant strains have rpoB alleles that encode the phenotype for susceptibility. Similarly, non-M. tuberculosis mycobacteria exhibit higher levels of baseline resistance to rifampin, despite the presence of rpoB alleles that encode the phenotype for susceptibility. To identify other genes involved in rifampin resistance, we generated a library of Mycobacterium smegmatis mc(2)155 transposon insertion mutants. Upon screening this library, we identified one mutant that was hypersensitive to rifampin. The transposon insertion was localized to the arr gene, which encodes rifampin ADP ribosyltransferase, an enzyme able to inactivate rifampin. Sequence analysis revealed differences in the arr alleles of M. smegmatis strain mc(2)155 and previously described strain DSM 43756. The arr region of strain mc(2)155 contains a second, partial copy of the arr gene plus a novel insertion sequence, IS1623.
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Affiliation(s)
- David C Alexander
- Department of Medical Genetics and Microbiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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Klein JL, Brown TJ, French GL. Rifampin resistance in Mycobacterium kansasii is associated with rpoB mutations. Antimicrob Agents Chemother 2001; 45:3056-8. [PMID: 11600355 PMCID: PMC90781 DOI: 10.1128/aac.45.11.3056-3058.2001] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rifampin is the most potent drug used in the treatment of disease due to Mycobacterium kansasii. A 69-bp fragment of rpoB, the gene that encodes the beta subunit of the bacterial RNA polymerase, was sequenced and found to be identical in five rifampin-susceptible clinical isolates of M. kansasii. This sequence showed 87% homology with the Mycobacterium tuberculosis gene, with an identical deduced amino acid sequence. In contrast, missense mutations were detected in the same fragment amplified from five rifampin-resistant isolates. A rifampin-resistant strain generated in vitro also harbored an rpoB gene missense mutation that was not present in the parent isolate. All mutations detected (in codons 513, 526, and 531) have previously been described in rifampin-resistant M. tuberculosis isolates. Rifampin MICs determined by E-test were <1 mg/liter for all rifampin-susceptible isolates and >256 mg/liter for all rifampin-resistant ones. In addition, four of the five rifampin-resistant isolates were also resistant to rifabutin. We have thus shown a strong association between rpoB gene missense mutations and rifampin resistance in M. kansasii. Although our results are derived from a small number of isolates and confirmation with larger numbers would be useful, they strongly suggest that mutations within rpoB form the molecular basis of rifampin resistance in this species.
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Affiliation(s)
- J L Klein
- Department of Infection, Guy's, King's and St. Thomas' School of Medicine, St. Thomas' Hospital, London SE1 7EH, United Kingdom.
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Imai T, Watanabe K, Mikami Y, Yazawa K, Ando A, Nagata Y, Morisaki N, Hashimoto Y, Furihata K, Dabbs ER. Identification and characterization of a new intermediate in the ribosylative inactivation pathway of rifampin by Mycobacterium smegmatis. Microb Drug Resist 2000; 5:259-64. [PMID: 10647083 DOI: 10.1089/mdr.1999.5.259] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Mycobacterium smegmatis DSM 43756 inactivates rifampin by ribosylation. To study this process of rifampicin, all possible inactivated forms of the antibiotic were extracted and purified. Structural studies showed the presence of a new inactivation product, designated RIP-TAp(23-phosphoribosyl-rifampin). Formation of 23-(O-ADP-ribosyl)rifampin (RIP-TAs) is the first step, followed by removal of AMP to give rise to the newly identified compound. Lastly, dephosphorylation leads to formation of 23-ribosyl-rifampin (RIP-Mb). Feeding experiments with the ADP-ribosylated antibiotic obtained from the cell homogenates of an Escherichia coli strain carrying the cloned M. smegmatis gene confirmed this rifampin inactivation process.
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Affiliation(s)
- T Imai
- Research Center for Pathogenic Fungi and Microbial Toxicoses, Chiba University, Japan
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Padayachee T, Klugman KP. Molecular basis of rifampin resistance in Streptococcus pneumoniae. Antimicrob Agents Chemother 1999; 43:2361-5. [PMID: 10508007 PMCID: PMC89483 DOI: 10.1128/aac.43.10.2361] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rifampin resistance among South African clinical isolates of Streptococcus pneumoniae was shown to be due to missense mutations within the rpoB gene. Sequence analysis of 24 rifampin-resistant isolates revealed the presence of mutations within cluster I as well as novel mutations in an area designated pneumococcus cluster III. Of the 24 isolates characterized, only 1 resistant isolate did not contain any mutations in the regions sequenced. Either the cluster I or the cluster III mutations separately conferred MICs of 32 to 128 microg/ml. Clinical isolate 55, for which the MIC was 256 microg/ml, was noted to contain 9 of the 10 mutations identified, which included the cluster I and cluster III mutations. As in Escherichia coli, it is possible that cluster I (amino acids 406 to 434) and cluster III (amino acids 523 to 600) of S. pneumoniae interact to form part of the antibiotic binding site, thus accounting for the very high MIC observed for isolate 55. PCR products containing cluster I or cluster III mutations were able to transform rifampin-susceptible S. pneumoniae to resistance. Although many of the isolates studied displayed identical sequences, pulsed-field gel electrophoresis analysis revealed that the isolates were not of clonal origin.
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Affiliation(s)
- T Padayachee
- Pneumococcal Diseases Research Unit of the MRC, SAIMR, and the University of the Witwatersrand, Johannesburg, South Africa.
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15
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Quan S, Imai T, Mikami Y, Yazawa K, Dabbs ER, Morisaki N, Iwasaki S, Hashimoto Y, Furihata K. ADP-ribosylation as an intermediate step in inactivation of rifampin by a mycobacterial gene. Antimicrob Agents Chemother 1999; 43:181-4. [PMID: 9869590 PMCID: PMC89045 DOI: 10.1128/aac.43.1.181] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mycobacterium smegmatis DSM43756 inactivates rifampin, and the inactivated antibiotic product recovered from culture medium was ribosylated on the 23-OH group. To study this process, the gene responsible for the inactivation was expressed at high levels by the lac promoter in Escherichia coli conferring resistance to >500 microg of antibiotic per ml. Cell homogenates generated a novel derivative designated RIP-TAs; in this study, we determined that RIP-TAs is 23-(O-ADP-ribosyl)rifampin. Our results indicated that RIP-TAs is an intermediate in the pathway leading to ribosylated rifampin and that the previously characterized gene encodes a mono(ADP-ribosyl)transferase which, however, shows no sequence similarity to other enzymes of this class.
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Affiliation(s)
- S Quan
- Genetics Department, University of the Witwatersrand, Johannesburg 2050, South Africa
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16
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Affiliation(s)
- A Telenti
- Department of Internal Medicine, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
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17
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Quan S, Venter H, Dabbs ER. Ribosylative inactivation of rifampin by Mycobacterium smegmatis is a principal contributor to its low susceptibility to this antibiotic. Antimicrob Agents Chemother 1997; 41:2456-60. [PMID: 9371349 PMCID: PMC164144 DOI: 10.1128/aac.41.11.2456] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Mycobacterium smegmatis inactivates rifampin by ribosylating this antibiotic. The gene responsible for this ability was cloned and was shown to confer low-level resistance to this antibiotic (MIC increase, about 12-fold) in related organisms. A 600-bp subclone responsible for ribosylating activity and resistance carried an open reading frame of 429 bp. Targeted disruption of the gene in M. smegmatis resulted in mutants with much increased susceptibility to rifampin (MICs of 1.5 instead of 20 microg/ml) as well as the loss of antibiotic-inactivating ability. Also, disruption of this gene led to a much lower frequency of occurrence of spontaneous high-level rifampin-resistant mutants.
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Affiliation(s)
- S Quan
- Genetics Department, University of the Witwatersrand, Johannesburg, South Africa
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Stevenson K, Sharp JM. The contribution of molecular biology to Mycobacterium avium subspecies Paratuberculosis research. Vet J 1997; 153:269-86. [PMID: 9232117 DOI: 10.1016/s1090-0233(97)80062-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Molecular biology has contributed to our knowledge and understanding of the structure of Mycobacterium avium subspecies paratuberculosis and has been particularly useful in determining those components that elicit immune responses in the host or discriminate M. avium paratuberculosis from other closely related environmental mycobacteria. As such, it has made a significant impact in the field of diagnosis, and has been instrumental in the development of specific and sensitive diagnostic tests. The next decade will see exciting new developments in paratuberculosis research as a consequence of substantial advances made in the construction of gene transfer systems in mycobacteria. These will provide opportunities for applying new strategies to determine the genetic basis for pathogenesis and the mechanisms of drug resistance and will offer new prospects for the rational design of efficient vaccines.
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Affiliation(s)
- K Stevenson
- Moredun Research Institute, Edinburgh, Scotland, UK
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Abstract
In the last few years, there has been considerable progress in our understanding of the mechanisms of action and resistance to antimycobacterials. To date, there is information about 11 genes involved in resistance in M. tuberculosis. This has prompted the development of novel tests for the rapid identification of resistant strains, and has provided invaluable insight into unique mycobacterial structures, which are important targets for the development of new inhibitory compounds.
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Affiliation(s)
- A Telenti
- Section of Infectious Diseases, University of Berne, Switzerland
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20
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Persing DH. Nucleic Acid-Based Discovery Techniques for Potential Xenozoonotic Pathogens. Xenotransplantation 1997. [DOI: 10.1007/978-3-642-60572-7_54] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Morris SL, Rouse DA. The genetics of multiple drug resistance in Mycobacterium tuberculosis and the Mycobacterium avium complex. Res Microbiol 1996; 147:68-73. [PMID: 8761725 DOI: 10.1016/0923-2508(96)80206-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- S L Morris
- Laboratory of Mycobacteria, Center for Biologics Evaluation and Research, Bethesda, MD 20892, USA
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22
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Affiliation(s)
- S T Cole
- Unité de Génétique Moléculaire Bactérienne, Institut Pasteur, Paris
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Maddry JA, Suling WJ, Reynolds RC. Glycosyltransferases as targets for inhibition of cell wall synthesis in M. tuberculosis and M. avium. Res Microbiol 1996; 147:106-12. [PMID: 8761730 DOI: 10.1016/0923-2508(96)80211-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- J A Maddry
- Southern Research Institute, Birmingham, AL 35255, USA
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Musser JM. Antimicrobial agent resistance in mycobacteria: molecular genetic insights. Clin Microbiol Rev 1995; 8:496-514. [PMID: 8665467 PMCID: PMC172873 DOI: 10.1128/cmr.8.4.496] [Citation(s) in RCA: 407] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The primary theme emerging from molecular genetic work conducted with Mycobacterium tuberculosis and several other mycobacterial species is that resistance is commonly associated with simple nucleotide alterations in target chromosomal genes rather than with acquisition of new genetic elements encoding antibiotic-altering enzymes. Mutations in an 81-bp region of the gene (rpoB) encoding the beta subunit of RNA polymerase account for rifampin resistance in 96% of M. tuberculosis and many Mycobacterium leprae isolates. Streptomycin resistance in about one-half of M. tuberculosis isolates is associated with missense mutations in the rpsL gene coding for ribosomal protein S12 or nucleotide substitutions in the 16S rRNA gene (rrs). Mutations in the katG gene resulting in catalase-peroxidase amino acid alterations nad nucleotide substitutions in the presumed regulatory region of the inhA locus are repeatedly associated with isoniazid-resistant M. tuberculosis isolates. A majority of fluoroquinolone-resistant M. tuberculosis isolates have amino acid substitutions in a region of the DNA gyrase A subunit homologous to a conserved fluoroquinolone resistance-determining region. Multidrug-resistant isolates of M. tuberculosis arise as a consequence of sequential accumulation of mutations conferring resistance to single therapeutic agents. Molecular strategies show considerable promise for rapid detection of mutations associated with antimicrobial resistance. These approaches are now amenable to utilization in an appropriately equipped clinical microbiology laboratory.
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Affiliation(s)
- J M Musser
- Department of Pathology, Baylor College of Medicine, Houston, TX 77030, USA
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25
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Hetherington SV, Watson AS, Patrick CC. Sequence and analysis of the rpoB gene of Mycobacterium smegmatis. Antimicrob Agents Chemother 1995; 39:2164-6. [PMID: 8540740 PMCID: PMC162905 DOI: 10.1128/aac.39.9.2164] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The rpoB gene encodes the beta subunit of the DNA-dependent RNA polymerase of bacteria. Mutations in defined areas result in resistance to rifampin. Mycobacterium smegmatis is naturally resistant to rifampin, but analysis of the rpoB gene revealed no identifiable rifampin resistance mutations. Another mechanism of resistance may be present.
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Affiliation(s)
- S V Hetherington
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
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Guerrero C, Bernasconi C, Burki D, Bodmer T, Telenti A. A novel insertion element from Mycobacterium avium, IS1245, is a specific target for analysis of strain relatedness. J Clin Microbiol 1995; 33:304-7. [PMID: 7714183 PMCID: PMC227937 DOI: 10.1128/jcm.33.2.304-307.1995] [Citation(s) in RCA: 225] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The insertion sequence IS1245 is a novel mycobacterial repetitive element identified in Mycobacterium avium. It encodes a transposase which exhibits a 64% amino acid similarity with IS1081, an insertion element present in the M. tuberculosis complex. The host range of IS1245 appears limited to M. avium as this element was not identified in M. intracellulare or in any other of 18 mycobacteria species tested. When IS1245 was used for restriction fragment length polymorphism (RFLP) analysis, human isolates characteristically presented a high number of copies (median, 16; range, 3 to 27) and a diversity of RFLP patterns comparable to that found by pulsed-field gel electrophoresis. Isolates from nonhuman sources differed both in number of copies and in RFLP pattern diversity: while swine isolates shared the characteristics of human strains, those from several avian sources exhibited a very low copy number of IS1245 and appeared clonal on the basis of RFLP.
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Affiliation(s)
- C Guerrero
- Institute for Medical Microbiology, University of Berne, Switzerland
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