[Use of the polymerase chain reaction to identify Helicobacter pylori in clinical material]

A new system for the detection of Helicobacter pylori DNA, based on the method of directed amplification, has been developed. Primers for specific detection of H. pylori were selected from a nucleotide sequence of 16 S-p RNA. The sequences of the primers had a few nucleotide substitutions as compared with the sequences of closely related microorganisms. An essential condition for the attainment of reaction specificity was the rise of annealing step temperature to 66 degrees C. Sensitivity of the system was in the range of 3 to 30 fg of DNA, or 20 to 100 bacterial cells. Using the proposed system for the detection of H. pylori DNA clinical specimens (stomach biopsy sample, gastric juice and wash-offs of oral cavity), obtained from 49 patients with antral gastritis, were analyzed. The method of H. pylori detection in clinical specimens using polymerase chain reaction (PCR) turned out to be more sensitive compared with microbiological tests. By application of PCR H. pylori DNA was detected in subgingival pockets.