Quantitation of Helicobacter pylori in the stomach using quantitative polymerase chain reaction assays

Background. The density of Helicobacter pylori is thought to correlate with the degree of inflammation and thus indirectly with the outcome of the inf ection. Rapid quantitative assays of H. pylori in gastric or duodenal mucos a are lacking. The aim was to develop quantitative assays using the polymer ase chain reaction to assess the quantity of H. pylori in the gastric mucos a. Methods. Competitive PCR was based on coamplification of a segment of the u reC sequence and an internal control using a single set of primers. PCR pro ducts were quantified colorimetrically by an enzyme-linked immunosorbent as say and compared with known quantities of the internal control standard add ed to the PCR reaction. The highly sensitive, noncompetitive PCR assay does not use coamplification and measures the amplified DNA sequence using a fl ash-type luminescent tag and a specific probe. The mouse infected model usi ng H. pylori strain SS-1 was used to develop the assays. Results. Quantification of H. pylori using either the competitive or noncom petitive PCR was reliable, highly sensitive and specific. Conclusions. The ability to rapidly quantitate H. pylori from gastric mucos a should be useful to investigate the role of H. pylori density and infecti on outcome, as well as to monitor the effectiveness of antibiotic treatment or vaccines against H. pylori.