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

Abstract

BackgroundDespite 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.MethodsA 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.ResultsOne 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%).ConclusionsHigh 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.

Genotyping of vacA alleles of <i>Helicobacter pylori</i> strains recovered from some Iranian food items

“…The role of foods in the transmission of H. pylori is still unknown but there are several studies on its isolation from various types of food like milk, vegetables and salad [4][5][6][7]. Favorable conditions for the growth of bacteria in various types of foods including ready to eat foods, meat, salads and vegetables would enhance H. pylori the survival [5,7].…”

“…Favorable conditions for the growth of bacteria in various types of foods including ready to eat foods, meat, salads and vegetables would enhance H. pylori the survival [5,7].…”

Synergistic effects of combined curcumin and antibiotic in ameliorating an animal model of Helicobacter pylori infection

“…The presence of microbial agents in the stomach was discovered about 100 years ago, but since the 1970's its association with gastritis (gastric mucosal inflammation) was diagnosed [16]. The prevalence of Helicobacter pylori infection was 50% to 80% respectively in developed and developing countries.…”

Genotyping pattern of the vacuolating cytotoxin A and cytotoxin associated gene A of the Helicobacter pylori strains detected in fecal samples of household dogs

“…[4][5][6][7] Documented data revealed a high homology in the DNA sequence of H. pylori strains isolated from household dogs and also those which cause severe gastroenteritis and other types of gastrointestinal diseases in their owners. 8 Therefore, close contact with healthy and complicated dogs which harbor H. pylori in their stomach has been determined to be a risk factor for human Helicobacter infection. [4][5][6][7][8] Study the distribution of putative genotypes is essential to assess the microbiological and epidemiological prospective of H. pylori in clinical cases.…”

“…8 Therefore, close contact with healthy and complicated dogs which harbor H. pylori in their stomach has been determined to be a risk factor for human Helicobacter infection. [4][5][6][7][8] Study the distribution of putative genotypes is essential to assess the microbiological and epidemiological prospective of H. pylori in clinical cases. The most imperative virulence genes accompanied with severe cases of H. pylori infections are vacuolating cytotoxin A (vacA) and cytotoxin associated gene A (cagA).…”