IDENTIFICATION OF HELICOBACTER-PYLORI IN SALIVA BY A NESTED PCR ASSAYDERIVED FROM A NEWLY CLONED DNA-PROBE

A novel probe was developed from genomic DNA of Helicobacter pylori AT CC type strain 43629. It hybridized with all 73 H. pylori clinical iso lates tested but not with any of 183 non-H. pylori DNAs in dot blot hy bridization. Typing tests revealed 41 different HaeIII-digestion patte rns from 57 H. pylori strains tested. Based on the sequence of the pro be, a nested PCR was developed that detected as little as 2 fg of H. p ylori DNA or approximately equivalent to one cell. No PCR products wer e amplified from any of 21 non-H. pylori strains tested. Using this ne sted PCR, H. pylori DNA was detected in 33 of 45 (73%) saliva samples collected from patients with gastric H. pylori infection. These data s uggest that the probe is useful for typing H. pylori and that the nest ed PCR is a valuable tool for detecting H. pylori DNA in saliva.