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Timestamp: 2019-04-24 12:31:34+00:00

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Many therapies for peptic ulcer disease have been tried, with the conclusion that multiple drug combinations are at present essential to the achievement of acceptable outcomes; cure of infection in >80% of patients is based on intention to treat. One class of drugs, which has been a constant from the early work of Marshall and Warren, is the 5-nitroimidazoles, principally tinidazole and metronidazole, agents that had been used in the treatment of anaerobic bacterial and selected protozoan infections. Two other drugs were also used with success subsequently: a macrolide compound, clarithromycin, and a β-lactam compound, amoxicillin. The issues relating to drug selection and antibiotic resistance as well as the prospect of using genomics for drug discovery is reviewed in this chapter. Resistance to 5-nitroimidazole is widespread. In the developed countries, it varies between 10 and 50% whereas in developing countries it may concern virtually all strains. Resistance to β-lactam antibiotics by gram-negative bacteria is most commonly due to the production of β-lactamase, either chromosomally encoded, or, more often, plasmid media. The methods used for H. pylori susceptibility testing can be divided into standard phenotypic methods on the basis of diffusion or dilution, and genotypic methods. In summary, despite the significant progress that has been made with respect to development of tests to detect antimicrobial resistance, additional work is needed to optimize the performance of the susceptibility testing methods of H. pylori, especially for metronidazole.
Chemical structure of the prodrug metronidazole. Metronidazole is activated by the reduction of the nitro group (arrow) leading to the generation of a reactive radical.
Binding of labeled erythromycin on increasing concentrations of H. pylori ribosomes.
1. Abdi, Y. M.,, K. A. Young,, D. S. Rampton,, J. M. Hardie,, R. A. Feldman,, and N. Banatvala. 1999. Comparison of the effects of anaerobic and microaerophilic incubation on resistance of Helicobacter pylori to metronidazole. J. Med. Microbiol. 48: 407– 410.
2. Akada, J. K.,, M. Shirai,, K. Fujii,, K. Okita,, and T. Nakazawa. 1999. In vitro anti-Helicobacter pylori activities of new rifamycin derivatives, KRM-1648 and KRM-1657. Antimicrob. Agents Chemother. 43: 1072– 1076.
3. Alarcon, T.,, D. Domingo,, and M. Lopez-Brea. 1998. Discrepancies between E-test and agar dilution methods for testing metronidazole susceptibility of Helicobacter pylori. J. Clin. Microbiol. 36: 1165– 1166.
4. Alarcon, T.,, D. Domingo,, and M. Lopez-Brea. 1999. Antibiotic resistance problems with Helicobacter pylori. Int. J. Antimicrob. Agents 12: 19– 26.
5. Alarcon, T.,, D. Domingo,, N. Prieto,, and M. Lopez-Brea. 2000. PCR using 3'-mismatched primers to detect A2142C mutation in 23S rRNA conferring resistance to clarithromycin in Helicobacter pylori clinical isolates. J. Clin. Microbiol. 38: 923– 925.
6. Alm, R. A.,, L. S. Ling,, D. T. Moir,, B. L. King,, E. D. Brown,, P. C. Doig,, D. R. Smith,, B. Noonan,, B. C. Guild,, B. L. deJonge,, G. Carmel,, P. J. Tummino,, A. Caruso,, M. Uria Nickelsen,, D. M. Mills,, C. Ives C,, R. Gibson,, D. Merberg,, S. D. Mills,, Q. Jiang,, D. E. Taylor,, G. F. Vovis,, and T. J. Trust. 1999. Genomic-sequence comparison of two unrelated isolates of the human gastric pathogen H. pylori. Nature 397: 176– 180.
7. Arner, E. S. J.,, M. Bjornstedt,, and A. Holmgren. 1995. 1-chloro-2,4-dinitrobenzene is an irreversible inhibitor of human thioredoxin reductase—loss of thioredoxin disulfide reductase activity is accompanied by a large increase in NADPH oxidase activity. J. Biol. Chem. 270: 3479– 3482.
8. Bergeron, M. G.,, and M. Ouelette. 1998. Preventing antibiotic resistance through rapid genotypic identification of bacteria and of their antibiotic resistance genes in the clinical microbiology laboratory. J. Clin. Microbiol. 36: 2169– 2172.
9. Bina, J. E.,, R. A. Aim,, M. Uria-Nickelsen,, S. R. Thomas,, T. J. Trust,, and R. E. W. Hancock. 2000. Helicobacter pylori uptake and efflux: basis for intrinsic susceptibility to antibiotics in vitro. Antimicrob. Agents Chemother. 44: 248– 254.
10. Blackstock, W. P.,, and M. P. Weir. 1999. Proteomics: quantitative and physical mapping of cellular proteins. Trends Biotechnol. 17: 121– 127.
11. Bock, H.,, H. Koop,, N. Lehn,, and M. Heep. 2000. Rifabutin-based triple therapy after failure of Helicobacter pylori eradication treatment: preliminary experience. J. Clin. Gastroenterol. 31: 222– 225.
12. Boyanova, L. 1999. Comparative evaluation of two methods for testing metronidazole susceptibility of Helicobacter pylori in routine practice. Diagn. Microbiol. Infect. Dis. 35: 33– 36.
13. Boyanova, L.,, I. Stancheva,, Z. Spassova,, N. Katzaerov,, I. Mitov,, and R. Koumanova. 2000. Primary and combined resistance to four antimicrobial agents in Helicobacter pylori in Sofia, Bulgaria. J. Med. Microbiol. 49: 415– 418.
14. Burucoa, C.,, G. Blasac,, J. V. Solnick,, and J. L. Fauchere. 2000. Helicobacter pylori: une bacterie spontanement hyper-mutatrice? Lett. Infect. 15( Suppl. 3): 30.
15. Cabrita, J.,, M. Oleastro,, R. Matos,, A. Manhente,, J. Cabral,, R. Barros,, A. I. Lopes,, P. Ramalho,, B. C. Neves,, and A. S. Guerreiro. 2000. Features and trends in Helicobacter pylori antibiotic resistance in Lisbon area, Portugal (1990-1999). J. Antimicrob. Chemother. 46: 1029– 1031.
16. Cafrert, S.,, F. P. Stewart,, K. Swarna,, and J. S. Wiseman. 1999. The use of informatics and automation to remove bottlenecks in drug discovery. Curr. Opin. Drug Disc. Dev. 2: 234– 238.
17. Calzi, M. L.,, and L. B. Poole. 1997. Requirement for the two AhpF cystine disulfide centers in catalysis of peroxide reduction by alkyl hydroperoxide reductase. Biochemistry 36: 13357– 13364.
18. Carlberg, I.,, and B. Mannervik. 1980. Oxidase activity of glutathione reductase effected by 2,4,6-trinitrobenzenesulfo-nate. FEBS Lett. 115: 265– 268.
19. Carlberg, I.,, L. Sahlman,, and B. Mannervik. 1985. The effect of 2,4,6-trinitrobenzenesulfonate on mercuric reductase, glutathione reductase and lipoamide dehydrogenase. FEBS Lett. 180: 102– 106.
20. Cederbrant, G.,, G. Kahlmeter,, and A. Ljungh. 1992. Proposed mechanism for metronidazole resistance in Helicobacter pylori. J. Antimicrob. Chemother. 29: 115– 120.
21. Cederbrant, G.,, G. Kahlmeter,, and A. Ljungh. 1993. The E test for antimicrobial susceptibility testing of Helicobacter pylori. J. Antimicrob. Chemother. 31: 65– 71.
22. Chaves, S.,, M. Gadanho,, R. Tenreiro,, and J. Cabrita. 1999. Assessment of metronidazole susceptibility in Helicobacter pylori: statistical validation and error rate analysis of breakpoints determined by the disk diffusion test. J. Clin. Microbiol. 37: 1628– 1631.
23. Cordwell, S. J. 1999. Microbial genomes and 'missing' enzymes: re-defining biochemical pathways? Arch. Microbiol. 172: 269– 279.
24. Cordwell, S. J.,, D. J. Basseal,, B. J. Bjellqvist,, D. C. Shaw,, and I. Humphery-Smith. 1997. Characterisation of basic proteins from Spiroplasma melliferum using novel immobilised pH gradients. Electrophoresis 18: 1393– 1398.
25. Cordwell, S. J.,, D. J. Basseal,, and I. Humphery-Smith. 1997. Proteome analysis of Spiroplasma melliferum (A56) and protein characterisation across species boundaries. Electrophoresis 18: 1335– 1346.
26. Coudron, P. E.,, and C. W. Stratton. 1995. Factors affecting growth and susceptibility testing of Helicobacter pylori in liquid media. J. Clin. Microbiol. 33: 1028– 1030.
27. Coudron, P. E.,, and C. W. Stratton. 1998. In vitro evaluation of nitrofurantoin as an alternative agent for metronidazole in combination antimicrobial therapy against Helicobacter pylori. J. Antimicrob. Chemother. 42: 657– 660.
28. Debets-Ossenkopp, Y. J.,, A. B. Brinkman,, E. J. Kuipers,, C. M. J. E. Vandenbroucke-Grauls,, and J. G. Kusters. 1998. Explaining the bias in the 23S rRNA gene mutations associated with clarithromycin resistance in clinical isolates of Helicobacter pylori. Antimicrob. Agents Chemother. 42: 2749– 2751.
29. Debets-Ossenkopp, Y. J.,, A. J. Herscheid,, R. G. J. Pot,, E. J. Kuipers,, J. G. Kusters,, and C. M. J. E. Vandenbroucke-Grauls. 1999. Prevalence of Helicobacter pylori resistance to metronidazole, clarithromycin, amoxycillin, tetracycline, and trovafloxacin in the Netherlands. J. Antimicrob. Chemother. 43: 511– 515.
30. Debets-Ossenkopp, Y. J.,, R. G. J. Pot,, D. J. van Westerloo,, A. Goodwin,, C. M. J. E. Vandenbroucke-Grauls,, D. E. Berg,, P. S. Hoffman,, and J. G. Kurters. 1999. Insertion of mini-IS605 and deletion of adjacent sequences in the nitroreductase (rdxA) gene cause metronidazole resistance in Helicobacter pylori NCTC11637. Antimicrob. Agents Chemother. 43: 2657– 2662.
31. Debets-Ossenkopp, Y. J.,, M. Spanius,, J. G. Kusters,, J. J. Kolkman,, and C. M. J. E. Vandenbroucke-Grauls. 1996. Mechanism of clarithromycin resistance in clinical isolates of Helicobacter pylori. FEMS Microbiol. Lett. 142: 37– 42.
32. de Boer, W. A.,, and G. N. J. Tytgat. 2000. Treatment of Helicobacter pylori infection. Br. Med. J. 320: 31– 34.
33. DeLoney, C. R.,, and N. L. Schiller. 1999. Competition of various β-lactam antibiotics for the major penicillin-binding proteins of Helicobacter pylori: antibacterial activity and effects on bacterial morphology. Antimicrob. Agents Chemother. 43: 2702– 2709.
34. DeLoney, C. R.,, and N. L. Schiller. 2000. Characterization of an in vitro selected amoxicillin resistant strain of Helicobacter pylori. Antimicrob. Agents Chemother. 44: 3368– 3373.
35. Dore, M. P.,, D. Y. Graham,, and A. R. Sepulveda. 1999. Different penicillin-binding protein profiles in amoxicillin-resistant Helicobacter pylori. Helicobacter 4: 154– 161.
36. Dore, M. P.,, D. Y. Graham,, A. R. Sepulveda,, G. Realdi,, and M. S. Osato. 1999. Sensitivity of amoxicillin-resistant Helicobacter pylori to other penicillins. Antimicrob. Agents Chemother. 43: 1803– 1804.
37. Dore, M. P.,, G. Leandro,, G. Realdi,, A. R. Sepulveda,, and D. Y. Graham. 2000. Effect of pre-treatment antibiotic resistance to metronidazole and clarithromycin on outcome of Helicobacter pylori therapy: a meta-analytical approach. Dig. Dis. Sci. 45: 68– 76.
38. Dore, M. P.,, M. S. Osato,, G. Realdi,, I. Mura,, D. Y. Graham,, and A. R. Sepulveda. 1999. Amoxycillin tolerance in Helicobacter pylori. J. Antimicrob. Chemother. 43: 47– 54.
39. Dore, M. P.,, A. Piana,, M. Carta,, A. Atzei,, B. M. Are,, I. Mura,, G. Massarelli,, A. Maida,, A. R. Sepulveda,, D. Y. Graham,, and G. Realdi. 1998. Amoxicillin resistance is one reason for failure of amoxicillin omeprazole treatment of Helicobacter pylori infection. Aliment. Pharmacol. Ther. 12: 635– 639.
40. Drews, J. 2000. D rug discovery: a historical perspective. Science 287: 1960– 1964.
41. Edwards, D. I. 1993. Nitroimidazole drugs—action and resistance mechanisms. I. Mechanisms of action. J. Antimicrob. Chemother. 31: 19– 20.
42. Fauchere, J. L., and Groupe d'Etude Francais des Helicobacters. 1999. Validation of a disk diffusion method for macrolide susceptibility testing of Helicobacter pylori. Gut 45( Suppl. 3): A9.
43. Garcia-Arata, M. I.,, F. Baquero,, L. de Rafael,, C. M. de Argila,, J. P. Gisbert,, F. Mermjo,, D. Boixeda,, and R. Canton. 1999. Mutations in 23S rRNA in Helicobacter pylori conferring resistance to erythromycin do not always confer resistance to clarithromycin. Antimicrob. Agents Chemother. 43: 374– 376.
44. Garcia Sanchez, J. E.,, N. Garcia Saenz,, M. Rodriguez Rincon,, I. Trujillano Martin,, E. Garcia Sanchez,, and M. J. Fresnadillo Martinez. 2000. Susceptibility of Helicobacter pylori to mupirocin, oxazolidinones, quinupristin/dalfopristin and new quinolones. J. Antimicrob. Chemother. 46: 283– 285.
45. Ge, Z.,, and D. E. Taylor. 1999. Contributions of genome sequencing to understanding of the biology of Helicobacter pylori. Annuv. Rev. Microbiol. 53: 353– 387.
46. Ghuysen, J. M. 1997. Penicillin-binding proteins. Wall peptidoglycan assembly and resistance to penicillin: facts, doubts and hopes. Int. J. Antimicrob. 8: 45– 60.
47. Gibson, J. R.,, N. A. Saunders,, B. Burke,, and R. J. Owen. 1999. Novel method for rapid determination of clarithromycin sensitivity in Helicobacter pylori. J. Clin. Microbiol. 37: 3746– 3748.
48. Gingeras, T. R.,, and C. Rosenow. 2000. Studying microbial genomics with high density oligonucleotide arrays. ASM News 66: 463– 467.
49. Glupczynski, Y.,, L. P. Andersen,, M. Lopez-Brea,, and F. Megraud. 1998. Towards standardisation of antimicrobial susceptibility testing of H. pylori: preliminary results by a European Multicentre Study Group. Gut 43( Suppl. 2): A47.
50. Glupczynski, Y.,, M. Delmee,, C. Briick,, M. Labbe,, V. Avesani,, and A. Burette. 1988. Susceptibility of clinical isolates of Campylobacter pylori to 24 antimicrobial and anti-ulcer agents. Eur. J. Epidemiol. 4: 154– 157.
51. Glupczynski, Y.,, M. Labbe,, W. Hansen,, F. Crokaert,, and E. Yourassowsky. 1991. Evaluation of the E-test for quantitative antimicrobial susceptibility testing of Helicobacter pylori. J. Clin. Microbiol. 29: 2072– 2075.
52. Goldman, R. C.,, D. Zakula,, R. Flamm,, J. Beyer,, and J. Capo-bianco. 1994. Tight binding of clarithromycin, its 14-(R)-hydroxy metabolite, and erythromycin to Helicobacter pylori ribosomes. Antimicrob. Agents Chemother. 38: 1496– 1500.
53. Goodwin, A.,, D. Kersulyte,, G. Sisson,, S.J. O. Veldhuyzenvan Zanten,, D. E. Berg,, and P. S. Hoffman. 1998. Metronidazole resistance in Helicobacter pylori is due to null mutations in a gene (rdxA) that encodes an oxygen-insensitive NADPH nitroreductase. Mol. Microbiol. 28: 383– 393.
54. Goodwin, C. S.,, B. J. Marshall,, E. D. Blincow,, D. H. Wilson,, S. Blackbourn,, and M. Philipps. 1988. Prevention of nitroimidazole resistance in Campylobacter pylori by coadministration of colloidal bismuth subcitrate: clinical and in vitro studies. J. Clin. Pathol. 41: 217– 220.
55. Graham, D. Y.,, M. S. Osato,, J. Hoffman,, A. R. Opekun,, S.-Y. Anderson,, and H. M. T. El-Zimaity. 2000. Furazolidone combination therapies for Helicobacter pylori infection in the United States. Aliment. Pharmacol. Ther. 14: 211– 215.
56. Grebe, T.,, and R. Hackenbeck. 1996. Penicillin-binding proteins 2b and 2x of Streptococcus pneumoniae are primary determinant resistants for different classes of β-lactam antibiotics. Antimicrob. Agents Chemother. 40: 829– 834.
57. Haas, C. E.,, D. E. Nix,, and J. J. Schentag. 1990. In vitro selection of resistant Helicobacter pylori. Antimicrob. Agents Chemother. 34: 1637– 1641.
58. Hachem, C. Y.,, J. E. Clarridge,, R. Reddy,, R. Flamm,, D. G. Evans,, S. K. Tanaka,, and D. Y. Graham. 1996. Antimicrobial susceptibility testing of Helicobacter pylori. Diagn. Microbiol. Infect. Dis. 24: 37– 41.
59. Hackenbeck, R. 1995. Target-mediated resistance to β-lactam antibiotics. Biochem. Pharmacol. 50: 1121– 1127.
60. Han, S. R.,, S. Bhakdi,, M. J. Maeurer,, T. Schneider,, and S. Gehring. 1999. Stable and unstable amoxicillin resistance in Helicobacter pylori: should antibiotic resistance testing be performed prior to eradication therapy? J. Clin. Microbiol. 37: 2740– 2741.
61. Harris, A. G.,, S. L. Hazell,, and A. G. Netting. 2000. Use of digoxigenin-la belled ampicillin in the identification of penicillin-binding proteins in H. pylori. J. Antimicrob. Chemother. 45: 591– 598.
62. Hartvig-Hartzen, S.,, L. P. Andersen,, A. Bremmelgaard,, H. Colding,, M. Arpi,, J. Kristiansen,, T. Justesen,, F. Espersen,, N. Frimodt-Moller,, and O. Bonnevie. 1997. Antimicrobial susceptibility testing of 230 Helicobacter pylori strains: importance of medium, inoculum and incubation time. Antimicrob. Agents Chemother. 41: 2634– 2639.
63. Haynes, P. A.,, S. P. Gygi,, D. Figeys,, and R. Aebersold. 1998. Proteome analysis: biological assay or data archive? Electrophoresis 19: 1862– 1871.
64. Hazell, S. L.,, and G. L. Mendz. 1997. How Helicobacter pylori works: an overview of the metabolism of Helicobacter pylori. Helicobacter 2: 1– 12.
65. Heep, M.,, D. Beck,, E. Bayerddrffer,, and N. Lehn. 1999. Rifampin and rifabutin resistance mechanisms in Helicobacter pylori. Antimicrob. Agents Chemother. 43: 1497– 1499.
66. Heep, M.,, U. Rieger,, D. Beck,, and N. Lehn. 2000. Mutations in the beginning of the rpoB gene can induce resistance to rifamycins in both Helicobacter pylori and Mycobacterium tuberculosis. Antimicrob. Agents Chemother. 44: 1075– 1077.
67. Heithoff, D. M.,, C. P. Conner,, P. C. Hanna,, S. M. Julio,, U. Hentschel,, and M. J. Mahan. 1997. Bacterial infection as assessed by in vivo gene expression. Proc. Natl. Acad. Sci. USA 94: 934– 939.
68. Henriksen, T. H.,, O. Brorson,, T. SchSyen,, T. Thoresen,, and A. Lia. 1997. A simple method for determining metronidazole resistance of Helicobacter pylori. J. Clin. Microbiol. 35: 1424– 1426.
69. Hirschl, A.,, M. M. Hirschl,, and M. L. Rotter. 1993. Comparison of three methods for the determination of the sensitivity of Helicobacter pylori to metronidazole. J. Antimicrob. Chemother. 32: 45– 49.
70. Hoffman, P. S.,, A. Goodwin,, J. Johnsen,, K. Magee,, and S. J. Veldhaygen van Zanten. 1996. Metabolic activities of metronidazole-sensitive and -resistant strains of Helicobacter pylori: repression of pyruvate oxidoreductase and expression of isocitrate lyase activity correlate with resistance. J. Bacteriol. 178: 4822– 4829.
71. Huang, J. Q.,, and R. H. Hunt. 1999. Treatment after failure: the problem of 'non-responders.' Gut 45(Suppl. l): 40– 44.
72. Hughes, N. J.,, P. A. Chalk,, C. L. Clayton,, and D. J. Kelly. 1995. Identification of carboxylation enzymes and characterization of a novel four-subunit pyruvate:flavodoxin oxidoreductase from Helicobacter pylori. J. Bacteriol. 177: 3953– 3959.
73. Hughes, N. J.,, C. L. Clayton,, P. A. Chalk,, and D. J. Kelly. 1998. Helicobacter pylori porCDAB and oorDABC genes encode distinct pyruvate:flavodoxin oxidoreductase and 2-oxogluterate: acceptor oxidoreductase which mediate electron transport to NADP. J. Bacteriol. 180: 1119– 1128.
74. Hulten, K.,, A. Gibreel,, O. Skold,, and L. Engstrand. 1997. Macrolide resistance in Helicobacter pylori: mechanism and stability in strains from clarithromycin-treated patients. Antimicrob. Agents Chemother. 41: 2550– 2553.
75. Huynen, M.,, T. Dandekar,, and P. Bork. 1998. Differential genome analysis applied to the species-specific features of Helicobacter pylori. FEBS Lett. 426: 1– 5.
76. Ikeda, F.,, Y. Yokota,, A. Ikemoto,, N. Teratani,, K. Shimomura,, and H. Kanno. 1995. Interaction of beta-lactam antibiotics with the penicillin-binding proteins of penicillin-resistant Streptococcus pneumoniae. Chemotherapy 41: 159– 164.
77. Ikeda, F.,, Y. Yokota,, Y. Mine,, and M. Tatsuta. 1990. Activity of cefixime against Helicobacter pylori and affinities for the penicillin-binding proteins. Antimicrob. Agents Chemother. 34: 2426– 2428.
78. Jacoby, G. A.,, and G. L. Archer. 1991. New mechanisms of bacterial resistance to antimicrobial agents. N. Engl.J. Med. 324: 601– 612.
79. Jenks, P. J.,, R. L. Ferrero,, and A. Labigne. 1999. The role of the rdxA gene in the evolution of metronidazole resistance in Helicobacter pylori. J. Antimicrob. Chemother. 43: 753– 758.
80. Jorgensen, M. A.,, J. Manos,, G. L. Mendz,, and S. L. Hazell. 1998. The mode of action of metronidazole in Helicobacter pylori: futile cycling or reduction? J. Antimicrob. Chemother. 41: 67– 75.
81. Kaihovaara, P.,, J. Hook-Nikanne,, M. Uusi-Oukari,, T. U. Kosunen,, and M. Salaspuro. 1995. Flavodoxin-dependent pyruvate oxidation, acetate production and metronidazole reduction by Helicobacter pylori. J. Antimicrob. Chemother. 41: 171– 177.
82. Krebs, R. 1999. Novel technology to improve pharmaceutical productivity. Curr. Opin. Drug Disc. Dev. 2: 239– 243.
83. Krisrwamurthy, P.,, M. H. Parlow,, J. Schneider,, S. Burroughs,, C. Wickland,, N. B. Vakil,, B. E. Dunn,, and S. H. Phadnis. 1999. Identification of a novel penicillin-binding protein from Helicobacter pylori. J. Bacteriol. 181: 5107– 5110.
84. Kunin, C. M. 1996. Antimicrobial activity of rifabutin. Clin. Infect. Dis. 22( Suppl. 1): S3– S13.
85. Kusters, J. G.,, D. F. Schuijffel,, M. M. Gerrits,, A. van Zwet,, and C. M. J. E. Vandenbroucke-Grauls. 1999. A PBP-1A homologue is involved in stable amoxicillin resistance of Helicobacter pylori. Gastroenterology 116: A226.
86. Kwon, D. H.,, F. A. K. El-Zaatari,, M. Kato,, M. S. Osato,, R. Reddy,, Y. Yamaoka,, and D. Y. Graham. 2000. Analysis of a rdxA gene and involvement of additional genes encoding NADPH flavin oxidoreductase (FrxA) and ferredoxin-like protein (FdxB) in metronidazole resistance of Helicobacter pylori. Antimicrob. Agents Chemother. 44: 2133– 2142.
87. Kwon, D. H.,, M. Kato,, F. A. K. El-Zaatari,, M. S. Osato,, and D. Y. Graham. 2000. Frame-shift mutations in NAD(P)H flavin oxidoreductase encoding gene frxA from metronidazole resistant Helicobacter pylori ATCC43504 and its involvement in metronidazole resistance. FEMS Microbiol. Lett. 188: 197– 202.
88. Kwon, D. H.,, J. J. Kim,, M. Lee,, Y. Yamaoka,, M. Kato,, M. S. Osato,, F. A. K. El-Zaatari,, and D. Y. Graham. 2000. Isolation and characterization of tetracycline-resistant clinical isolates of Helicobacter pylori. Antimicrob. Agents Chemother. 44: 3203– 3205.
89. Kwon, D. H.,, M. Lee,, J. J. Kim,, J. G. Kim,, F. A. K. El-Zaatari,, M. S. Osato,, and D. Y. Graham. 2001. Furazolidone- and nitrofurantoin-resistant Helicobacter pylori: prevalence and role of genes involved in metronidazole resistance. Antimicrob. Agents Chemother. 45: 306– 308.
90. Kwon, D. H.,, M. S. Osato,, D. Y. Graham,, and F. A. K. El-Zaatari. 2000. Quantitative RT-PCR analysis of multiple genes encoding putative metronidazole nitroreductases from Helicobacter pylori. Int. J. Antimicrob. Agents 15: 31– 36.
91. Labenz, J.,, E. Gyenes,, U. Peitz,, and G. Borsch. 1991. Ciprofloxacin-omeprazole combination therapy for eradication of Helicobacter pylori. Z. Gastroenterol. 29: 143– 145.
92. Lenski, R. E. 1997. The cost of antibiotic resistance from the perspective of a bacterium. Ciba Found. Symp. 207: 131– 140.
93. Lin, S.,, W. R. Cullen,, and D. J. Thomas. 1999. Methylarsenicals and arsinothiols are potent inhibitors of mouse liver thioredoxin reductase. Chem. Res. Toxicol. 12: 924– 930.
94. Lind, T.,, S. V. van Zanten,, P. Unge,, R. Spiller,, E. Bayerdorffer,, C. O'Morain,, K. dev Bardhan,, M. Braderte,, N. Cbiba,, M. Wrangstadh,, C. Cederberg,, and J. Idstrom. 1996. Eradication of Helicobacter pylori using one week triple therapies combining omeprazole with two antimicrobials: The MACH 1 study. Helicobacter 1: 138– 144.
95. Livermore, D. M. 1995. β-lactamases in laboratory and clinical resistance. Clin. Microbiol. Rev. 8: 557– 584.
96. Logan, R. P.,, P. A. Gummett,, J. J. Misiewicz,, Q. N. Karim,, M. M. Walker,, and J. H. Baron. 1993. Two-week eradication regimen for metronidazole-resistant Helicobacter pylori. Aliment. Pharmacol. Ther. 7: 149– 153.
97. Lopez-Brea, M.,, D. Domingo,, I. Sanchez,, and T. Alarcon. 1997. Evolution of resistance to metronidazole and clarithromycin in Helicobacter pylori clinical isolates from Spain. J. Antimicrob. Chemother. 40: 279– 281.
98. Maeda, S.,, H. Yoshida,, H. Matsunaga,, K. Ogura,, O. Kawamata,, Y. Shiratori,, and M. Omata. 2000. Detection of clarithromycin-resistant H. pylori strains by a preferential homo-duplex formation assay. J. Clin. Microbiol. 38: 210– 214.
99. Malfertheiner, P.,, F. Megraud,, C. O'Morain,, D. Bell,, G. Bianch-Porro,, M. Deltenre, and The European Helicobacter pylori Study Group. 1997. Current European concepts in the management of Helicobacter pylori infection—the Maastricht consensus report. Gut 41: 8– 13.
100. Malouin, F.,, and L. E. Bryan. 1986. Modification of penicillin-binding proteins as mechanisms of β-lactam resistance. Antimicrob. Agents Chemother. 30: 1– 5.
101. Marais, A.,, G. L. Mendz,, S. L. Hazell,, and F. Megraud. 1999. Metabolism and genetics of Helicobacter pylori: the genome era. Microbiol. Mol. Biol. Rev. 3: 642– 674.
102. Marais, A.,, L. Monteiro,, A. Occhialini,, M. Pina,, H. Lamouliatte,, and F. Megraud. 1999. Direct detection of Helicobacter pylori resistance to macrolides by a polymerase chain reaction/DNA enzyme immunoassay in gastric biopsy specimens. Gut 44: 463– 467.
103. Marshall, B. J.,, C. S. Goodwin,, J. R. Warren,, R. Murray,, E. D. Blincow,, S. J. Blackbourn,, M. Phillips,, T. E. Waters,, and C. R. Sanderson. 1988. Prospective double-blind trial of duodenal ulcer relapse after eradication of Campylobacter pylori. Lancet 2: 1437– 1442.
104. Martinez, J. L.,, and F. Baquero. 2000. Mutation frequencies and antibiotic resistance. Antimicrob. Agents Chemother. 44: 1771– 1777.
105. Matsuoka, M.,, Y. Yosbida,, K. Hayakawa,, S. Fukuchi,, and K. Sugona. 1999. Simultaneous colonisation of Helicobacter pylori with and without mutations in the 23S rRNA gene in patients with no history of clarithromycin exposure. Gut 45: 503– 507.
106. McOsker, C. C.,, and P. M. Fitzpatrick. 1994. Nitrofurantoin: mechanisms of action and implication for resistance development in common uropathogens. J. Antimicrob. Chemother. 33(Suppl. A): 23– 30.
107. Megraud, F. 1998. Epidemiology and mechanism of antibiotic resistance in Helicobacter pylori. Gastroenterology 115: 1278– 1282.
108. Megraud, F.,, C. Camou-Juncas,, A. Occhialini,, and C. Birac. 1996. Helicobacter pylori resistance levels to clarithromycin remain stable. Gastroenterology 110: A192.
109. Megraud, F.,, and H. P. Doermann. 1998. Clinical relevance of resistant strains of Helicobacter pylori: a review of current data. Gut 43( Suppl. 1): S61– S65.
110. Megraud, F.,, N. Lehn,, T. Lind,, E. Bayerdorffer,, C. O'Morain,, R. Spiller,, P. Unge,, S. Veldhuyzen van Zanten,, M. Wrangstadh,, and C. F. Burman. 1999. Antimicrobial susceptibility testing of Helicobacter pylori in a large multicenter trial: the MACH2 study. Antimicrob. Agents Chemother. 43: 2747– 2752.
111. Mendelman, P. M. 1992. Targets of the 0-lactam antibiotics, penicillin-binding proteins, in ampicillin-resistant, non-β-lactamase-producing Haemophilus influenzae. J. Infect. Dis. 165( Suppl. 1): S107– S109.
112. Mendonca, S.,, C. Ecclissato,, M. S. Sartori,, A. P. Ortiz Godoy,, R. A. Aparecida Guerzoni,, M. Degger,, and J. Pedrazzoli, Jr. 2000. Prevalence of Helicobacter pylori resistance to metronidazole, clarithromycin, amoxicillin, tetracycline, and furazolidone in Brazil. Helicobacter 5: 79– 83.
113. Mendz, G. L.,, and S. L. Hazell. 1996. The urea cycle of Helicobacter pylori. Microbiology 142: 2959– 2967.
114. Mendz, G. L.,, B. M. Jimenez,, S. L. Hazell,, A. M. Gero,, and W.J. O'Sullivan. 1994. De novo synthesis of pyrimidine nucleotides by Helicobacter pylori. J. Appl. Bacteriol. 77: 1– 8.
115. Mendz, G. L.,, B. M. Jimenez,, S. L. Hazell,, A. M. Gero,, and W. J. O'Sullivan. 1994. Salvage synthesis of purine nucleotides by Helicobacter pylori. J. Appl. Bacteriol. 77: 674– 681.
116. Mentis, A. F.,, E. Roma,, A. Pangalis,, and E. Katsiyiannakis. 2000. Susceptibilities of Helicobacter pylori strains isolated from children with gastritis to selected antibiotics. J. Antimicrob. Chemother. 44: 717– 722.
117. Midolo, P. D.,, M. G. Korman,, J. D. Turnidge,, and J. R. Lambert. 1996. Helicobacter pylori resistance to tetracycline. Lancet 347: 1194– 1195.
118. Midolo, P. D.,, J. Turnidgz,, J. R. Lambert,, and J. M. Bell. 1995. Validation of a modified Kirby-Bauer disk diffusion method for metronidazole susceptibility testing of Helicobacter pylori. Diagn. Microbiol. Infect. Dis. 21: 135– 140.
119. Moir, D. T.,, K. J. Shaw,, R. S. Hare,, and G. F. Vovis. 1999. Genomics and antimicrobial drug discovery. Antimicrob. Agents Chemother. 43: 439– 446.
120. Moore, R. A.,, B. Beckthold,, S. Wong,, A. Kureishi,, and L. E. Bryan. 1995. Nucleotide sequence of the gyrA gene and characterization of ciprofloxacin-resistant mutants of Helicobacter pylori. Antimicrob. Agents Chemother. 39: 107– 111.
121.National Committee for Clinical Laboratory Standards. 1999. Performance Standards for Antimicrobial Susceptibility Testing. Vlth Informational Supplement M100 S9, 19,1. National Committee for Clinical Laboratory Standards, Villanova, Pa,.
122. Neuwirth, C.,, E. Siebor,, J.-M. Duez,, A. Pechinot,, and A. Kazmierczak. 1995. Imipenem resistance in clinical isolates of Proteus mirabilis associated with alterations in penicillin-binding proteins. J. Antimicrob. Chemother. 36: 335– 342.
123.NIH Consensus Conference. 1994. Helicobacter pylori in peptic ulcer disease. JAMA 272: 65– 69.
124. Nikaido, H. 1996. Multidrug efflux pumps of gram-negative bacteria. J. Bacteriol. 178: 5853– 5859.
125. Nordberg, J.,, L. Zhong,, A. Holmgren,, and E. S. J. Arner. 1998. Mammalian thioredoxin reductase is irreversibly inhibited by dinitrohalobenzenes by alkylation of both the redox active selenocysteine and its neighboring cysteine residue. J. Biol. Chem. 273: 10835– 10842.
126. Occhialini, A.,, M. Urdaci,, F. Doucet-Populaire,, C. M. Bebeéar,, H. Lamouliatte,, and F. Megraud. 1997. Macrolide resistance in Helicobacter pylori: rapid detection of point mutations and assays of macrolide binding to ribosomes. Antimicrob. Agents Chemother. 41: 2724– 2728.
127. Perri, F.,, V. Festa,, R. Clemente,, M. Quitadamo,, and A. Andriulli. 2000. Rifabutin-based 'rescue therapy' for Helicobacter pylori infected patients after failure of standard regimens. Aliment. Pharmacol. Ther. 14: 311– 316.
128. Piccolomini, R.,, G. Di Bonaventura,, G. Catamo,, F. Carbone,, and M. Neri. 1997. Comparative evaluation of the E-test, agar dilution, and broth dilution for testing susceptibility of Helicobacter pylori strains to 20 antimicrobial agents. J. Clin. Microbiol. 35: 1842– 1846.
129. Pina, M.,, A. Occhialini,, L. Monteiro,, H. P. Doermann,, and F. Megraud. 1998. Detection of point mutations associated with resistance of Helicobacter pylori to clarithromycin by hybridization in liquid phase. J. Clin. Microbiol. 36: 3285– 3290.
130. Realdi, G.,, M. P. Dore,, A. Piana,, A. Atzei,, M. Carta,, L. Cugia,, A. Manca,, B. M. Arc,, G. Massarelli,, I. Mura,, A. Maida,, and D. Y. Graham. 1999. Pretreatment antibiotic resistance in Helicobacter pylori infection: results of three randomized controlled trials. Helicobacter 4: 106– 112.
131. Reece, R. J.,, and A. Maxwell. 1991. DNA gyrase: structure and function. Crit. Rev. Biochem. Mol. Biol. 26: 335– 375.
132. Rosamond, J.,, and A. Allsop. 2000. Harnessing the power of the genome in the search for new antibiotics. Science 287: 1973– 1976.
133. Samuelson, J. 1999. Why metronidazole is active against both bacteria and parasites. Antimicrobial. Agents Chemother. 43: 1533– 1541.
134. Service, R. F. 2000. Structural genomics offers high-speed look at proteins. Science 287: 1954– 1956.
135. Sigmund, C. D.,, and E. A. Morgan. 1992. Erythromycin resistance due to a mutation in a ribosomal RNA of Escherichia coli. Proc. Natl. Acad. Sci. USA 79: 5602– 5606.
136. Smith, C.,, J. Perkins,, and D. Tompkins. 1997. Comparison of E-test and disc diffusion for detection of antibiotic resistance in Helicobacter pylori. Microbiol. Digest. 14: 21– 23.
137. Smith, M. A.,, and D. I. Edwards. 1995. Redox potential and oxygen concentration as factors in the susceptibility of Helicobacter pylori to nitroheterocyclic drugs. J. Antimicrob. Chemother. 35: 751– 764.
138. Smith, M. A.,, and D. I. Edwards. 1997. Oxygen scavenging, NADH oxidase and metronidazole resistance in Helicobacter pylori. J. Antimicrob. Chemother. 39: 347– 353.
139. Sbrberg, M.,, H. Hanberger,, M. Nilsson,, A. Bjorkma,, and L. E. Nilsson. 1998. Risk of development of in vitro resistance to amoxicillin, clarithromycin, and metronidazole in Helicobacter pylori. Antimicrob. Agents Chemother. 42: 1222– 1228.
140. Spratt, B. 1977. Properties of penicillin-binding proteins of Escherichia coli K12. Eur. J. Biochem. 72: 341– 352.
141. Spratt, B. G. 1988. Hybrid penicillin-binding proteins in penicillin-resistant isolates of Neisseria gonorrhoeae. Nature 332: 173– 176.
142. Spratt, B. G.,, and A. B. Pardee. 1975. Penicillin-binding proteins and cell shape in E. coli. Nature 254: 516– 517.
143. Stone, G. G.,, D. Shortridge,, J. Versalovic,, R. K. Flamm,, J. Beyer,, A. T. Ghoneim,, D. Y. Graham,, and S. K. Tanaka. 1997. A PCR-oligonucleotide ligation assay to determine the prevalence of 23S rRNA gene mutations in clarithromycin-resistant Helicobacter pylori. Antimicrob. Agents Chemother. 41: 712– 714.
144. Stone, J. W.,, R. Wise,, I. A. Donovan,, and J. Gearty. 1988. Failure of ciprofloxacin to eradicate Campylobacter pylori from the stomach. J. Antimicrob. Chemother. 22: 92– 93.
145. Szczebara, F.,, L. Dhaemens,, P. Vincent,, and M. O. Husson. 1997. Evaluation of rapid molecular methods for detection of clarithromycin resistance in Helicobacter pylori. Eur. J. Clin. Microbiol. Infect. Dis. 16: 162– 164.
146. Takahashi, Y.,, N. Masuda,, M. Otsuki,, M. Miki,, and T. Nishino. 1997. In vitro activity of HSR-903, a new quinolone. Antimicrob. Agents Chemother. 41: 1326– 1330.
147. Tankovich, J.,, D. Lamarque,, J. C. Delchier,, C. J. Soussy,, A. Labigne,, and P. J. Jenks. 2000. Frequent association between alterations of the rdxA gene and metronidazole resistance in French and north African isolates of Helicobacter pylori. Antimicrob. Agents Chemother. 44: 608– 613.
148. Tao, H.,, C. Bausch,, C. Richmond,, F. R. Blattner,, and T. Conway. 1999. Functional genomics: expression analysis of Escherichia coli growing on minimal and rich medium. J. Bacteriol. 181: 6425– 6440.
149. Taylor, D. E.,, Z. Ge,, D. Purych,, T. Lo,, and K. Hiratsuka. 1997. Cloning and sequence analysis of two copies of a 23S rRNA gene from Helicobacter pylori and association of clarithromycin resistance with 23S rRNA mutations. Antimicrob. Agents Chemother. 41: 2621– 2628.
150. Tomb, J.-F.,, O. White,, A. R. Kerlavage,, R. A. Clayton,, G. G. Sutton,, R. D. Fleischmann,, K. A. Ketchum,, H. P. Klenk,, S. Gill,, B. A. Dougherty,, K. Nelson,, J. Quackenbush,, L. Zhou,, E. F. Kirkness,, S. Peterson,, B. Loftus,, D. Richardson,, R. Dodson,, H. G. Khalak,, A. Glodek,, K. McKenney,, L. M. Fitzegerald,, N. Lee,, M. D. Adams,, E. K. Hickey,, D. E. Berg,, J. D. Gocayne,, T. R. Utterback,, J. D. Peterson,, J. M. Kelley,, M. D. Cotton,, J. M. Weidman,, C. Fujii,, C. Bowman,, W. Whattey,, E. Wallin,, W. S. Hayes,, M. Borodovsky,, P. D. Karp,, H. O. Smith,, C. M. Fraser,, and J. C. Venter. 1997. The complete genome sequence of H. pylori. Nature 388: 539– 547.
151. Trebesius, K.,, K. Pauthel,, S. Strobel,, K. Vogt,, G. Faller,, T. Kirchner,, M. Kist,, J. Heeseman,, and R. Haas. 2000. Rapid and specific detection of Helicobacter pylori macrolide resistance in gastric tissue by fluorescent in situ hybridisation. Gut 46: 608– 614.
152. Valdez, Y.,, B. Velapatino,, R. H. Gilman,, V. Guttierez,, and C. Leon. 1998. Antimicrobial susceptibility of Helicobacter pylori determined by the E test using tetrazolium egg yolk agar. J. Clin. Microbiol. 36: 2784– 2785.
153. van der Wouden, E. J.,, J. C. Thijs,, J. H. Kleibeuker,, and A. A. Van Zwet. 1999. Subpopulations of Helicobacter pylori are responsible for discrepancies in the outcome of nitroimidazole susceptibility testing. Antimicrob. Agents Chemother. 43: 1484– 1486.
154. van der Wouden, E. J.,, J. C. Thijs,, W. J. Sluiter,, and J. H. Kleibeuker. 1999. The influence of in vitro nitroimidazole resistance on the efficacy of nitroimidazole-containing anti- Helicobacter pylori regimens: a meta-analysis. Am. J. Gastroenterol. 94: 1751– 1759.
155. van Doom, L. J.,, Y. J. Debets-Ossenkopp,, A. Marais,, R. Sanna,, F. Megraud,, J. G. Kusters,, and W. G. V. Quinnt. 1999. Rapid detection, by PCR and reverse hybridization, of mutations in the Helicobacter pylori 23S rRNA gene, associated with macrolide resistance. Antimicrob. Agents Chemother. 43: 1779– 1782.
156. van Doom, L. J.,, Y. Glupczynski,, J. G. Kusters,, F. Megraud,, P. Midolo,, J. C. Piffaretti,, D. Queiroz,, N. Nouhan,, E. Stet,, and W. Quint. Accurate prediction of macrolide resistance of Helicobacter pylori by the PCR line probe assay (LiPA) for the detection of mutations in the 23 S rDNA. A multicenter validation study. Submitted for publication.
156. van Zwet, A. A.,, C. M. J. E. Vandenbroucke-Grauls,, J. C. Thijs,, E. J. van der Wouden,, M. M. Gerrits,, and J. G. Kusters. 1998. Stable amoxicillin resistance in Helicobacter pylori. Lancet 352: 1595.
158. Versalovic, J.,, D. Shortridge,, K. Kliber,, V. Griffy,, J. Beyer,, R. K. Flamm,, S. K. Tanaka,, D. Y. Graham,, and M. F. Go. 1996. Mutations in 23S rRNA are associated with clarithromycin resistance in Helicobacter pylori. Antimicrob. Agents Chemother. 40: 477– 480.
159. Versalovic, J.,, M. S. Osato,, K. Spakovsky,, M. P. Dore,, R. Reddy,, G. G. Stone,, D. Shortridge,, R. K. Flamm,, S. K. Tanaka,, and D. Y. Graham. 1997. Point mutations in the 23S rRNA gene of Helicobacter pylori associated with different levels of clarithromycin resistance. J. Antimicrob. Chemother. 40: 283– 286.
160. Wang, G. E.,, S. M. Rahman,, M. Z. Humayun,, and D. E. Taylor. 1999. Multiplex sequence analysis demonstrates the competitive growth advantage of the A-to-G mutants of clarithromycin-resistant Helicobacter pylori. Antimicrob. Agents Chemother. 43: 683– 685.
161. Weissfeld, A.,, D. Simmon,, P. Rose,, S. Kidd,, N. Lukasik,, and N. Siepman. 1997. Susceptibility of Helicobacter pylori to clarithromycin and amoxicillin in the US. Gastroenterology 112: A329.
162. Whiteway, J.,, P. Koziarz,, J. Veall,, N. Sandhu,, P. Kumar,, B. Hoecher,, and I. B. Lambert. 1998. Oxygen-insensitive nitroreductases: analysis of the roles of nfsA and nfsB in the development of resistance to 5-nitrofuran derivatives in Escherichia coli. J. Bacteriol. 180: 5529– 5539.
163. Wilson, M.,, J. DeRisi,, H. H. Kristensen,, P. Imboden,, S. Rane,, P. O. Brown,, and G. K. Schoolnik. 2000. Exploring drug induced alterations in gene expression in Mycobacterium tuberculosis by microarray hybridization. Proc. Natl. Acad. Sci. USA 96: 12833– 12838.
164. Wittwer, C. T.,, K. M. Ririe,, R. V. Andrew,, D. A. David,, R. A. Gundry,, and U. J. Balis. 1997. The Lightcycler™: a microvolume multisample fluorimeter with rapid temperature control. BioTechniques 22: 176– 181.
165. Wolle, K.,, M. Nilius,, A. Leodolter,, W. A. Muller,, P. Malfer-theiner,, and W. Kdnig. 1998. Prevalence of Helicobacter pylori resistance to several antimicrobial agents in Germany. Eur. J. Clin. Microbiol. Infect. Dis. 17: 519– 521.
166. Wu, H.,, X. D. Shi,, H. T. Wang,, and J. X. Limu 2000. Resistance of Helicobacter pylori to metronidazole, tetracycline and amoxycillin. J. Antimicrob. Chemother. 46: 121– 123.
167. Xia, H.,, M. Buckley,, C. T. Keane,, and C. A. O'Morain. 1996. Clarithromycin resistance in Helicobacter pylori: prevalence in untreated dyspeptic patients and stability in vitro. J. Antimicrob. Chemother. 37: 473– 481.
168. Xia, H.,, C. T. Keane,, S. Beattie,, and C. A. O'Morain. 1994. Standardization of disk diffusion and its clinical significance for susceptibility testing of metronidazole against Helicobacter pylori. Antimicrob. Agents Chemother. 38: 2357– 2361.
169. Zhang, Z.,, P. J. Hillas,, and P. R. O. de Montellano. 1999. Reduction of peroxides and dinitrobenzenes by Mycobacterium tuberculosis thioredoxin and thioredoxin reductase. Arch. Biochem. Biophys. 363: 19– 26.

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