title: Anti-Helicobacter pylori therapy in India: differences in eradication efficiency associated with particular alleles of vacuolating cytotoxin (vacA) gene.
abstract: OBJECTIVE
  The efficiency of Helicobacter pylori eradication varies geographically, as do many parameters that might affect therapeutic efficiency, including bacterial genotype. The aim of the present study was to determine the efficiency of H. pylori eradication using a 10-day proton pump inhibitor-based triple-therapy regimen (omeprazole, clarithromycin and amoxycillin) in an eastern Indian patient population, and to find out the relationship, if any, of the success or failure of the therapy to known features of bacterial genotype.
  
  
  METHODS
  Helicobacter pylori infections were analyzed in 66 duodenal ulcer patients by upper gastrointestinal endoscopy, rapid urease tests, histology and culture. The cytotoxin-associated gene (cagA) and vacuolating cytotoxin (vacA) gene status of cultured strains were studied by polymerase chain reaction. Treatment was given for 10 days and endoscopy was repeated at 4 and 12 weeks post therapy to monitor ulcer healing and H. pylori eradication.
  
  
  RESULTS
  Ulcer healing was observed in 60 patients (96.77%). Helicobacter pylori was eradicated in 41 (62.12% intention to treat, 66.13% per protocol) of the 66 duodenal ulcer patients, but not in the other 25. The bacteria from 47 patients were genotyped. The only significant disease-associated difference in patterns observed was that the vacA m1 allele was represented more disproportionately among patients with eradication failures (68%) than in those with successful eradication (39%) (P < 0.05) No significant association of vacAs1 (signal sequence allele) or cag pathogenicity island status with persistence was detected.
  
  
  CONCLUSIONS
  This study highlights the public health need for cheaper, more cost-effective anti-H. pylori therapies for developing countries, and suggests that subtle features of bacterial genotype can influence therapeutic efficiency. The possibility that particular vacA mid region alleles affect persistence, perhaps through toxin action on particular gastric cell types, merits further study.
authors.affiliation: Department of Gastroenterology, Institute of Post Graduate Medical Education and Research, Kolkata, India.
authors.forename: Sujit
authors.initials: S
authors.lastname: Chaudhuri
authors.forename: Abhijit
authors.initials: A
authors.lastname: Chowdhury
authors.forename: Simanti
authors.initials: S
authors.lastname: Datta
authors.forename: Asish K
authors.initials: AK
authors.lastname: Mukhopadhyay
authors.forename: Santanu
authors.initials: S
authors.lastname: Chattopadhya
authors.forename: Dhira R
authors.initials: DR
authors.lastname: Saha
authors.forename: Gopal
authors.initials: G
authors.lastname: Dhali
authors.forename: Amal
authors.initials: A
authors.lastname: Santra
authors.forename: G Balakrish
authors.initials: GB
authors.lastname: Nair
authors.forename: Sujit
authors.initials: S
authors.lastname: Bhattacharya
authors.forename: Douglas E
authors.initials: DE
authors.lastname: Berg
mesh_terms: D000328:Adult; D000483:Alleles; D000658:Amoxicillin / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D000897:Anti-Ulcer Agents / Q000627:therapeutic use; D000942:Antigens, Bacterial / Q000235:genetics; D001426:Bacterial Proteins / Q000032:analysis / Q000235:genetics*; D017291:Clarithromycin; D003603:Cytotoxins / Q000235:genetics; D004269:DNA, Bacterial / Q000032:analysis; D004359:Drug Therapy, Combination; D004381:Duodenal Ulcer / Q000188:drug therapy / Q000382:microbiology*; D005260:Female; D005798:Genes, Bacterial; D016481:Helicobacter Infections / Q000175:diagnosis / Q000188:drug therapy* / Q000235:genetics*; D016480:Helicobacter pylori / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D007194:India; D008297:Male; D009853:Omeprazole / Q000627:therapeutic use
chemical_list: D000900:Anti-Bacterial Agents; D000897:Anti-Ulcer Agents; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D003603:Cytotoxins; D004269:DNA, Bacterial; C074689:VacA protein, Helicobacter pylori; C080866:cagA protein, Helicobacter pylori; D000658:Amoxicillin; D017291:Clarithromycin; D009853:Omeprazole