This is a revised version of an application to study the molecular genetics of H. pylori (Hp). Dr. Berg took the critique of the previous version so much to heart that he has prepared what is in essence an entirely new application. Therefore, he has not responded in detail to the previous critique and no more need be said about it. The present application is focussed on emerging antibiotic resistance in Hp and on the possibility of extensive genetic exchange within the species. Dr. Berg notes that Hp shows a remarkable genotypic diversity with respect to fingerprinting markers as well as specific proteins such as those implicated in virulence. The molecular basis for this diversity is, however, unknown, though it has been observed that Hp isolates are frequently transformable, often highly so, and could engage in DNA exchange in vivo. As might have been expected, resistance to clathromycin (Cla) and metronidazole (Met), two widely used drugs, has been on the rise, especially in the third world, where these drugs are used indiscriminately. Neither the mechanisms of resistance nor the responsible genes have been identified to date. Dr. Berg has two specific aims, namely to identify and characterize the genes for Cla and Met resistances and to analyze genetic recombination among Hp strains in vivo. In preliminary studies, he has developed the RAPD and PCR-RFLP methods for genotyping of Hp,and shown that these methods are more sensitive than MLEE, and that plasmid variability does not contribute disproportionately to typing specificity. He also showed that RAPD was useful for pedigree analysis of laboratory K12 strains and that observed variations were often at or near the replication terminus, possibly owing to decay of the replication complex at the terminus in strains stored on stabs. With respect to Hp, Dr. Berg has demonstrated infection with multiple Hp strains and confirmed joint multiple infection in a gnotobioticpiglet model - which appears to be a very good model for Hp infection. Finally, he has constructed an ordered cosmid library of 68 units with 3 gaps, and found the order of genes to be quite different from that in a different strain mapped by PFGE.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
1R01AI038166-01
Application #
2075096
Study Section
Bacteriology and Mycology Subcommittee 2 (BM)
Project Start
1995-01-01
Project End
1997-12-31
Budget Start
1995-01-01
Budget End
1995-12-31
Support Year
1
Fiscal Year
1995
Total Cost
Indirect Cost
Name
Washington University
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
062761671
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Velapatino, Billie; Balqui, Jacqueline; Gilman, Robert H et al. (2006) Validation of string test for diagnosis of Helicobacter pylori infections. J Clin Microbiol 44:976-80
Finger, S Alison; Velapatino, Billie; Kosek, Margaret et al. (2006) Effectiveness of enterobacterial repetitive intergenic consensus PCR and random amplified polymorphic DNA fingerprinting for Helicobacter pylori strain differentiation. Appl Environ Microbiol 72:4713-6
Albert, Thomas J; Dailidiene, Daiva; Dailide, Giedrius et al. (2005) Mutation discovery in bacterial genomes: metronidazole resistance in Helicobacter pylori. Nat Methods 2:951-3
Datta, S; Chattopadhyay, S; Patra, R et al. (2005) Most Helicobacter pylori strains of Kolkata in India are resistant to metronidazole but susceptible to other drugs commonly used for eradication and ulcer therapy. Aliment Pharmacol Ther 22:51-7
Datta, Simanti; Chattopadhyay, Santanu; Chowdhury, Abhijit et al. (2005) Diagnosis and genotyping of Helicobacter pylori by polymerase chain reaction of bacterial DNA from gastric juice. J Gastroenterol Hepatol 20:1253-9
Kalia, Awdhesh; Mukhopadhyay, Asish K; Dailide, Giedrius et al. (2004) Evolutionary dynamics of insertion sequences in Helicobacter pylori. J Bacteriol 186:7508-20
McNulty, Shannon L; Mole, Beth M; Dailidiene, Daiva et al. (2004) Novel 180- and 480-base-pair insertions in African and African-American strains of Helicobacter pylori. J Clin Microbiol 42:5658-63
Chattopadhyay, Santanu; Patra, Rajashree; Ramamurthy, T et al. (2004) Multiplex PCR assay for rapid detection and genotyping of Helicobacter pylori directly from biopsy specimens. J Clin Microbiol 42:2821-4
Dailidiene, Daiva; Dailide, Giedrius; Ogura, Keiji et al. (2004) Helicobacter acinonychis: genetic and rodent infection studies of a Helicobacter pylori-like gastric pathogen of cheetahs and other big cats. J Bacteriol 186:356-65
Kersulyte, Dangeruta; Kalia, Awdhesh; Zhang, MaoJun et al. (2004) Sequence organization and insertion specificity of the novel chimeric ISHp609 transposable element of Helicobacter pylori. J Bacteriol 186:7521-8

Showing the most recent 10 out of 59 publications