Antibacterial Activity of Garlic ( Allium sativum L. ) on Multi-Drug Resistant Helicobacter pylori Isolated From Gastric Biopsies

Garlic (Allium sativum L.) exhibit a broad-spectrum of antimicrobial activity against both gram negative and gram-positive bacteria. Helicobacter pylori (H. pylori) is the main factor in peptic and duodenal ulcer diseases. Some strains of H. pylori have become resistant to the current antibiotics. The purpose of this study was to determine the antibacterial effects of garlic on H. pylori. The gastric biopsies were inoculated on Brucella agar base (Conda Pronadisa, Spain) supplemented with 5% sterile sheep blood, 7 % fetal calf serum, vancomycin (5 mg/L), trimethoprim (5 mg/L), and polymyxin B (2500 U/L). Antibiotic susceptibility to garlic and commercial antibiotic disc was determined by agar disc diffusion method. In this study, ten strains of H. pylori out of 120 samples were isolated. The minimum inhibitory concentration of garlic extract for all isolates ranged between 25- 400 mg/mL. Resistance rates of 10 strains of H. pylori to amoxicillin, ciprofloxacin, clarithromycin, metronidazole, and tetracycline were 20%, 20%, 30%, 60%, and 30%, respectively. In this study, the antibacterial effect of aqueous extract of garlic on all H. pylori clinical isolates was confirmed. These findings might help us to use a new strategy for treatment of peptic ulcer.