title: Anti-Helicobacter pylori activity of Lactobacillus delbrueckii subsp. bulgaricus strains: preliminary report.
abstract: OBJECTIVE
  To evaluate the activities of six Lactobacillus delbrueckii subsp. bulgaricus (LB) strains against 30 Helicobacter pylori strains by agar-well diffusion method.
  
  
  RESULTS
  LB cultures [4 x 10(8)-4 x 10(9) CFU ml(-1)) either were prepared in milk at their native pH, 3.8-5.0, or were adjusted to pH 6.4-7.7. At low and neutralized pH, LB strains inhibited the growth by 40-86.7% and 16.7-66.7% of H. pylori strains, respectively. LB activity was strain-dependent. At low and neutralized pH, one and five H. pylori strains, respectively, were not inhibited by any LB strain. LB2 and LB3, taken together, were active against most metronidazole and clarithromycin resistant strains.
  
  
  CONCLUSIONS
  All LB strains inhibited a number of H. pylori strains, including also antibiotic resistant strains. LB activity was strain-dependent and better at low pH. At low pH values, the most active LB strains were LB1, LB2 and LB3, inhibiting 86.7% of H. pylori strains, while at neutralized pH values, the most active LB strains were LB2 and LB3, inhibiting 53.3 and 66.7% of H. pylori strains, respectively.
  
  
  CONCLUSIONS
  LB could be utilized in the treatment or prophylaxis of H. pylori infection and warrants clinical investigations.
authors.affiliation: Department of Microbiology, Medical University of Sofia, Sofia, Bulgaria. l.boyanova@hotmail.com
authors.forename: L
authors.initials: L
authors.lastname: Boyanova
authors.forename: M
authors.initials: M
authors.lastname: Stephanova-Kondratenko
authors.forename: I
authors.initials: I
authors.lastname: Mitov
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000898:Antibiosis; D002648:Child; D005260:Female; D016481:Helicobacter Infections / Q000382:microbiology*; D016480:Helicobacter pylori / Q000187:drug effects / Q000302:isolation & purification / Q000502:physiology*; D006801:Humans; D007778:Lactobacillus / Q000502:physiology*; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents