title: Helicobacter pylori isolates from proximal and distal stomach of patients never treated and already treated show genetic variability and discordant antibiotic resistance.
abstract: BACKGROUND
  The treatment failure of Helicobacter pylori (H. pylori) infection may be mainly because of antibiotic resistance and the presence of a mixed infection in the same patient.
  
  
  OBJECTIVE
  To investigate the incidence of mixed infection and discordant antibiotic resistance in patients never treated and already treated.
  
  
  METHODS
  Susceptibility test to amoxicillin, rifabutin, tinidazole, clarithromycin, levofloxacin, and moxifloxacin was conducted on H. pylori strains culture from 76 patients never treated and 72 patients already treated unsuccessfully. DNA fingerprinting was determined on H. pylori strains harboring in the same patient with a discordant resistance to the same antibiotic.
  
  
  RESULTS
  Forty percent of patients never treated and 53% of patients already treated showed a pangastric infection. The overall resistance to amoxicillin, clarithromycin, and tinidazole was significantly higher in patients with pangastric infection in comparison with those with the infection in the antrum (P<0.05). Discordant resistance was present in 33% of patients never treated, and 21% of patients already treated. DNA fingerprinting showed substantial differences among DNA patterns suggesting a mixed infection.
  
  
  CONCLUSIONS
  Culture and susceptibility test should be performed when necessary not only in the antrum but also in the fundus of patients with H. pylori infection.
authors.affiliation: Digestive Physiopathology Unit, Ospedale Civile Pescara, G. d'Annunzio University, Chieti-Pescara, Italy. marzio@unich.it
authors.forename: Leonardo
authors.initials: L
authors.lastname: Marzio
authors.forename: Lugina
authors.initials: L
authors.lastname: Cellini
authors.forename: Maria
authors.initials: M
authors.lastname: Amitrano
authors.forename: Rossella
authors.initials: R
authors.lastname: Grande
authors.forename: Mariaelena
authors.initials: M
authors.lastname: Serio
authors.forename: Giorgio
authors.initials: G
authors.lastname: Cappello
authors.forename: Laurino
authors.initials: L
authors.lastname: Grossi
mesh_terms: D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D001706:Biopsy; D001944:Breath Tests; D016009:Chi-Square Distribution; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000302:isolation & purification*; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D005260:Female; D005748:Gastric Fundus / Q000382:microbiology*; D005773:Gastroscopy; D014644:Genetic Variation; D005838:Genotype; D016481:Helicobacter Infections / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology / Q000382:microbiology; D016480:Helicobacter pylori / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D015994:Incidence; D007558:Italy; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D010641:Phenotype; D011706:Pyloric Antrum / Q000382:microbiology*; D017211:Treatment Failure; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial