Virulence factors and antibiotic resistance of Helicobacter pylori isolated from raw milk and unpasteurized dairy products in Iran

Background: despite the high importance ofhelicobacter 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 ofh. pylorito humans. the aim of the present study was to determine the distribution ofvaca,caga,iceaandoipavirulence factors inh. pyloristrains 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 wereh. pylori-positive were analyzed for the presence ofvaca,caga,iceaandoipavirulence 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 withh. pylori. the most frequently contaminated samples were ovine milk (35%) and traditional cheese (30%). total prevalence ofvaca,caga,iceaandoipafactors were 75%,76.6%,41.6% and 25%,respectively.h. pyloristrains 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 ofh. pylorisuggest that milk and dairy samples may be the sources of bacteria that can cause severe infection. our findings should raise awareness about antibiotic resistance inh. pyloristrains in iran. © 2014 mousavi et al.