Sheep may be a natural host for Helicobacter pylori

The isolation of Helicobacter pylori from sheep milk and gastric tissue suggests that sheep may be a natural host for the bacterium, according to a report in May's American Journal of Gastroenterology.

A team from Houston, Texas, USA, examined whether Helicobacter pylori infection might be transmitted from sheep to humans.

Milk and gastric tissue from sheep were cultured and analyzed by PCR amplification using three sets of primers Helicobacter genus-specific 16S rRNA and two sets of primers specific for H. pylori vacA gene.

Helicobacter DNA was demonstrated in 60% (38/63) of milk samples and in 30% (6/20) of sheep tissue samples.

Proportion of samples with H. pylori DNA: - Milk: 60% - Tissue: 30%

American Journal of Gastroenterology

H. pylori vacA gene was amplified in 5 of 38 milk samples, and in 2 of 6 sheep tissue samples respectively.

H. pylori were cultured from sheep milk and tissue samples and confirmed as the bacterium on the basis of colony morphology, positive biochemical reactions, and negative Gram stain.

Sequence analysis of 16S rRNA PCR products from these isolates demonstrated 99% identity with H. pylori.

Researcher M. P. Dore, of the VA Medical Center and Baylor College of Medicine, concluded on behalf of colleagues, "The presence of H. pylori in sheep stomach, in the absence of associated gastritis, suggests that sheep may be a natural host for H. pylori.

"The additional recovery of H. pylori from sheep milk and gastric tissue further support this hypothesis."