DETECTION OF HELICOBACTER PYLORI AND VIRULENCE-ASSOCIATED GENES IN SALIVA SAMPLES OF ASYMPTOMATIC PERSONS IN NORTHEAST THAILAND.

The aims of the study were to develop nested-PCR (targeting vacA and cagA), SYBR green quantitative PCR (targeting 16S rDNA) tests and compared them with indirect fluorescent-monoclonal antibody (IFA) method for determination of the prevalence of Helicobacter pylori in 118 saliva samples from asymptomatic individuals in Khon Kaen, Thailand. Detection limit of both PCR-based assays was one cell. Prevalence of H. pylori in saliva samples was 55% based on the criterion of positivity of IFA test and one of the PCR-based methods or positivity of both PCR assays. Forty-nine percent of H. pylori detected carried cagA, encoding a cytotoxin associated with severe clinical outcomes. These results imply that the mouth may be an important reservoir for H. pylori, with nearly 50% of the virulent type that could possibly lead to gastroduodenal disease.