title: Virulence factors and antibiotic resistance of Helicobacter pylori isolated from raw milk and unpasteurized dairy products in Iran.
abstract: BACKGROUND
  Despite the high importance of Helicobacter pylori, the origin and transmission of this bacterium has not been clearly determined. According to controversial theories and results of previous studies, animal source foods - especially milk - play an important role in the transmission of H. pylori to humans. The aim of the present study was to determine the distribution of vacA, cagA, iceA and oipA virulence factors in H. pylori strains isolated from milk and dairy products and study their antimicrobial resistance properties.
  
  
  METHODS
  A total of 520 raw milk and 400 traditional dairy product samples were cultured and tested. Those that were H. pylori-positive were analyzed for the presence of vacA, cagA, iceA and oipA virulence factors. Antimicrobial susceptibility testing was performed by the disk diffusion method.
  
  
  RESULTS
  One hundred and three out of 520 milk samples (19.8%) and 77 out of 400 dairy products samples (19.2%) were contaminated with H. pylori. The most frequently contaminated samples were ovine milk (35%) and traditional cheese (30%). Total prevalence of vacA, cagA, iceA and oipA factors were 75%, 76.6%, 41.6% and 25%, respectively. H. pylori strains of milk and dairy products harbored high levels of resistance to ampicillin (84.4%), tetracycline (76.6%), erythromycin (70.5%) and metronidazole (70%).
  
  
  CONCLUSIONS
  High presence of antibiotic-resistant strains of H. pylori suggest that milk and dairy samples may be the sources of bacteria that can cause severe infection. Our findings should raise awareness about antibiotic resistance in H. pylori strains in Iran.
authors: Young Researches and Elites Club, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran.
authors: Soolmaz
authors: S
authors: Mousavi
authors: Young Researches and Elites Club, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran.
authors: Farhad Safarpoor
authors: FS
authors: Dehkordi
authors: Department of Food Hygiene, College of Veterinary Medicine, Islamic Azad University, Shahrekord Branch, PO Box 166, Shahrekord, Iran.
authors: Ebrahim
authors: E
authors: Rahimi
keywords: Antibiotic resistance properties; Dairy products; Helicobacter pylori; Iran; Milk; Virulence factors