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Antimicrob Agents Chemother. 1997 Aug; 41(8): 1677–1681.
PMCID: PMC163984

Ethambutol resistance in Mycobacterium tuberculosis: critical role of embB mutations.


Ethambutol [(S,S')-2,2'-(ethylenediimino)di-1-butanol; EMB], is a first-line drug used to treat tuberculosis. To gain insight into the molecular basis of EMB resistance, we characterized the 10-kb embCAB locus in 16 EMB-resistant and 3 EMB-susceptible genetically distinct Mycobacterium tuberculosis strains from diverse localities by automated DNA sequencing and single-stranded conformation polymorphism analysis. All 19 organisms had virtually identical sequences for the entire 10-kb region. Eight EMB-resistant organisms had mutations located in codon 306 of embB that resulted in the replacement of the wild-type Met residue with Ile or Val. Automated sequence analysis of the 5' region (1,892 bp) of embB in an additional 69 EMB-resistant and 30 EMB-susceptible M. tuberculosis isolates from diverse geographic localities and representing 70 distinct IS6110 fingerprints confirmed the unique association of substitutions in amino acid residue 306 of EmbB with EMB resistance. Six other embB nucleotide substitutions resulting in four amino acid replacements were uniquely found in resistant strains. Sixty-nine percent of epidemiologically unassociated EMB-resistant organisms had an amino acid substitution not found in susceptible strains, and most (89%) replacements occurred at amino acid residue 306 of EmbB. For strains with the Met306Leu or Met306Val replacements EMB MICs were generally higher (40 microg/ml) than those for organisms with Met306Ile substitutions (20 microg/ml). The data are consistent with the idea that amino acid substitutions in EmbB alter the drug-protein interaction and thereby cause EMB resistance.

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Selected References

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  • Beggs WH, Andrews FA. Nonspecific ionic inhibition of ethambutol binding by Mycobacterium smegmatis. Antimicrob Agents Chemother. 1973 Aug;4(2):115–119. [PMC free article] [PubMed]
  • Belanger AE, Besra GS, Ford ME, Mikusová K, Belisle JT, Brennan PJ, Inamine JM. The embAB genes of Mycobacterium avium encode an arabinosyl transferase involved in cell wall arabinan biosynthesis that is the target for the antimycobacterial drug ethambutol. Proc Natl Acad Sci U S A. 1996 Oct 15;93(21):11919–11924. [PMC free article] [PubMed]
  • Bloch AB, Cauthen GM, Onorato IM, Dansbury KG, Kelly GD, Driver CR, Snider DE., Jr Nationwide survey of drug-resistant tuberculosis in the United States. JAMA. 1994 Mar 2;271(9):665–671. [PubMed]
  • Bodmer T, Zürcher G, Imboden P, Telenti A. Mutation position and type of substitution in the beta-subunit of the RNA polymerase influence in-vitro activity of rifamycins in rifampicin-resistant Mycobacterium tuberculosis. J Antimicrob Chemother. 1995 Feb;35(2):345–348. [PubMed]
  • Cohn DL, Bustreo F, Raviglione MC. Drug-resistant tuberculosis: review of the worldwide situation and the WHO/IUATLD Global Surveillance Project. International Union Against Tuberculosis and Lung Disease. Clin Infect Dis. 1997 Jan;24 (Suppl 1):S121–S130. [PubMed]
  • Cooksey RC, Morlock GP, McQueen A, Glickman SE, Crawford JT. Characterization of streptomycin resistance mechanisms among Mycobacterium tuberculosis isolates from patients in New York City. Antimicrob Agents Chemother. 1996 May;40(5):1186–1188. [PMC free article] [PubMed]
  • Deng L, Mikusová K, Robuck KG, Scherman M, Brennan PJ, McNeil MR. Recognition of multiple effects of ethambutol on metabolism of mycobacterial cell envelope. Antimicrob Agents Chemother. 1995 Mar;39(3):694–701. [PMC free article] [PubMed]
  • Finken M, Kirschner P, Meier A, Wrede A, Böttger EC. Molecular basis of streptomycin resistance in Mycobacterium tuberculosis: alterations of the ribosomal protein S12 gene and point mutations within a functional 16S ribosomal RNA pseudoknot. Mol Microbiol. 1993 Sep;9(6):1239–1246. [PubMed]
  • Gangadharam PR, Gonzales ER. Influence of the medium on the in vitro susceptibility of Mycobacterium tuberculosis to ethambutol. Am Rev Respir Dis. 1970 Oct;102(4):653–655. [PubMed]
  • Heifets LB, Iseman MD, Lindholm-Levy PJ. Ethambutol MICs and MBCs for Mycobacterium avium complex and Mycobacterium tuberculosis. Antimicrob Agents Chemother. 1986 Dec;30(6):927–932. [PMC free article] [PubMed]
  • Heym B, Honoré N, Truffot-Pernot C, Banerjee A, Schurra C, Jacobs WR, Jr, van Embden JD, Grosset JH, Cole ST. Implications of multidrug resistance for the future of short-course chemotherapy of tuberculosis: a molecular study. Lancet. 1994 Jul 30;344(8918):293–298. [PubMed]
  • Kapur V, Whittam TS, Musser JM. Is Mycobacterium tuberculosis 15,000 years old? J Infect Dis. 1994 Nov;170(5):1348–1349. [PubMed]
  • Kapur V, Li LL, Iordanescu S, Hamrick MR, Wanger A, Kreiswirth BN, Musser JM. Characterization by automated DNA sequencing of mutations in the gene (rpoB) encoding the RNA polymerase beta subunit in rifampin-resistant Mycobacterium tuberculosis strains from New York City and Texas. J Clin Microbiol. 1994 Apr;32(4):1095–1098. [PMC free article] [PubMed]
  • Kapur V, Li LL, Hamrick MR, Plikaytis BB, Shinnick TM, Telenti A, Jacobs WR, Jr, Banerjee A, Cole S, Yuen KY, et al. Rapid Mycobacterium species assignment and unambiguous identification of mutations associated with antimicrobial resistance in Mycobacterium tuberculosis by automated DNA sequencing. Arch Pathol Lab Med. 1995 Feb;119(2):131–138. [PubMed]
  • Kilburn JO, Takayama K, Armstrong EL, Greenberg J. Effects of ethambutol on phospholipid metabolism in Mycobacterium smegmatis. Antimicrob Agents Chemother. 1981 Feb;19(2):346–348. [PMC free article] [PubMed]
  • Maddry JA, Suling WJ, Reynolds RC. Glycosyltransferases as targets for inhibition of cell wall synthesis in M. tuberculosis and M. avium. Res Microbiol. 1996 Jan-Feb;147(1-2):106–112. [PubMed]
  • Meier A, Sander P, Schaper KJ, Scholz M, Böttger EC. Correlation of molecular resistance mechanisms and phenotypic resistance levels in streptomycin-resistant Mycobacterium tuberculosis. Antimicrob Agents Chemother. 1996 Nov;40(11):2452–2454. [PMC free article] [PubMed]
  • Mikusová K, Slayden RA, Besra GS, Brennan PJ. Biogenesis of the mycobacterial cell wall and the site of action of ethambutol. Antimicrob Agents Chemother. 1995 Nov;39(11):2484–2489. [PMC free article] [PubMed]
  • Moghazeh SL, Pan X, Arain T, Stover CK, Musser JM, Kreiswirth BN. Comparative antimycobacterial activities of rifampin, rifapentine, and KRM-1648 against a collection of rifampin-resistant Mycobacterium tuberculosis isolates with known rpoB mutations. Antimicrob Agents Chemother. 1996 Nov;40(11):2655–2657. [PMC free article] [PubMed]
  • Morris S, Bai GH, Suffys P, Portillo-Gomez L, Fairchok M, Rouse D. Molecular mechanisms of multiple drug resistance in clinical isolates of Mycobacterium tuberculosis. J Infect Dis. 1995 Apr;171(4):954–960. [PubMed]
  • Musser JM. Antimicrobial agent resistance in mycobacteria: molecular genetic insights. Clin Microbiol Rev. 1995 Oct;8(4):496–514. [PMC free article] [PubMed]
  • Musser JM, Kapur V, Williams DL, Kreiswirth BN, van Soolingen D, van Embden JD. Characterization of the catalase-peroxidase gene (katG) and inhA locus in isoniazid-resistant and -susceptible strains of Mycobacterium tuberculosis by automated DNA sequencing: restricted array of mutations associated with drug resistance. J Infect Dis. 1996 Jan;173(1):196–202. [PubMed]
  • Nair J, Rouse DA, Bai GH, Morris SL. The rpsL gene and streptomycin resistance in single and multiple drug-resistant strains of Mycobacterium tuberculosis. Mol Microbiol. 1993 Nov;10(3):521–527. [PubMed]
  • Ohno H, Koga H, Kohno S, Tashiro T, Hara K. Relationship between rifampin MICs for and rpoB mutations of Mycobacterium tuberculosis strains isolated in Japan. Antimicrob Agents Chemother. 1996 Apr;40(4):1053–1056. [PMC free article] [PubMed]
  • Paulin LG, Brander EE, Pösö HJ. Specific inhibition of spermidine synthesis in Mycobacteria spp. by the dextro isomer of ethambutol. Antimicrob Agents Chemother. 1985 Jul;28(1):157–159. [PMC free article] [PubMed]
  • Silve G, Valero-Guillen P, Quemard A, Dupont MA, Daffe M, Laneelle G. Ethambutol inhibition of glucose metabolism in mycobacteria: a possible target of the drug. Antimicrob Agents Chemother. 1993 Jul;37(7):1536–1538. [PMC free article] [PubMed]
  • Takayama K, Kilburn JO. Inhibition of synthesis of arabinogalactan by ethambutol in Mycobacterium smegmatis. Antimicrob Agents Chemother. 1989 Sep;33(9):1493–1499. [PMC free article] [PubMed]
  • Takiff HE, Salazar L, Guerrero C, Philipp W, Huang WM, Kreiswirth B, Cole ST, Jacobs WR, Jr, Telenti A. Cloning and nucleotide sequence of Mycobacterium tuberculosis gyrA and gyrB genes and detection of quinolone resistance mutations. Antimicrob Agents Chemother. 1994 Apr;38(4):773–780. [PMC free article] [PubMed]
  • Telenti A, Imboden P, Marchesi F, Lowrie D, Cole S, Colston MJ, Matter L, Schopfer K, Bodmer T. Detection of rifampicin-resistance mutations in Mycobacterium tuberculosis. Lancet. 1993 Mar 13;341(8846):647–650. [PubMed]
  • Telenti A, Imboden P, Marchesi F, Schmidheini T, Bodmer T. Direct, automated detection of rifampin-resistant Mycobacterium tuberculosis by polymerase chain reaction and single-strand conformation polymorphism analysis. Antimicrob Agents Chemother. 1993 Oct;37(10):2054–2058. [PMC free article] [PubMed]
  • Telenti A, Philipp WJ, Sreevatsan S, Bernasconi C, Stockbauer KE, Wieles B, Musser JM, Jacobs WR., Jr The emb operon, a gene cluster of Mycobacterium tuberculosis involved in resistance to ethambutol. Nat Med. 1997 May;3(5):567–570. [PubMed]
  • van Embden JD, Cave MD, Crawford JT, Dale JW, Eisenach KD, Gicquel B, Hermans P, Martin C, McAdam R, Shinnick TM, et al. Strain identification of Mycobacterium tuberculosis by DNA fingerprinting: recommendations for a standardized methodology. J Clin Microbiol. 1993 Feb;31(2):406–409. [PMC free article] [PubMed]
  • Wolucka BA, McNeil MR, de Hoffmann E, Chojnacki T, Brennan PJ. Recognition of the lipid intermediate for arabinogalactan/arabinomannan biosynthesis and its relation to the mode of action of ethambutol on mycobacteria. J Biol Chem. 1994 Sep 16;269(37):23328–23335. [PubMed]
  • Xu C, Kreiswirth BN, Sreevatsan S, Musser JM, Drlica K. Fluoroquinolone resistance associated with specific gyrase mutations in clinical isolates of multidrug-resistant Mycobacterium tuberculosis. J Infect Dis. 1996 Nov;174(5):1127–1130. [PubMed]

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