Identification of Helicobacter suis in pig-producing regions of the United States

Objectives: To develop a non-culture-based method to determine levels of Helicobacter suis infection in porcine stomachs and to test the method in a sample of pigs from a variety of regions in the United States. Materials and methods: A polymerase chain reaction (PCR) assay was developed to quantitate total Helicobacter generic DNA and Helicobacter suis species-specific DNA in pig stomachs. Primers were derived from 16s ribosomal RNA (rRNA) gene sequences, selected on the basis of relative conservation and divergence of sequences across the various Helicobacter species. The assay was standardized using cloned 16s rRNA sequences and was initially tested with DNA isolated from cultured H suis. Gastric mucosal scrapings were collected from pigs in three geographic regions of the United States, including the North (Minnesota and Michigan), East Central (Iowa), and South (Oklahoma and North Carolina). Results: Of a total of 118 pigs tested, approximately half (55.1%; 95% CI, 46.1%-63.8%) were positive for H suis DNA. Helicobacter suis DNA was detected in pigs from all states tested. Implications: Helicobacter suis is present in US pigs and may be relevant to pig health and production. This quantitative PCR assay will facilitate further study of H suis in pigs, including potential therapeutic and prophylactic interventions.