A DNA PROBE FOR THE DIAGNOSIS OF CAMPYLOBACTER PYLORIDIS GASTRITIS

THE ROLE OF A SPECIFIC BACTERIUM AS THE POSSIBLE ETIOLOGIC AGENT OF GASTRITIS OR PEPTIC ULCER IS SUPPORTED BY A GROWINGSCIENTIFIC LITERATURE. HOWEVER, THE DIFFICULTY OF CONVENT- IONAL SAMPLING AND DIAGNOSTIC TECHNIQUES HAS RESTRICTED ADVANCES IN DISEASE DIAGNOSIS. THE PURPOSE OF THIS PHASE I PROJECT IS TO DEVELOP A DNA PROBE FROM THE CHROMOSOMAL DNA OF CAMPYLOBACTER PYLORIDIS, A MICROORGANISM RECENTLY SHOWN TO BE ASSOCIATED WITH GASTRITIS AND PEPTIC ULCER. THE 32P- LABELED PROBE WILL BE HYBRIDIZED TO CULTURED BACTERIAL DNA IMMOBILIZED ON NITROCELLULOSE. HYBRIDIZATION SPECIFICITY WILL BE EVALUATED IN A STANDARD NACL SOLUTION AND IN A NEW SALT SOLUTION, TETRAETHYLAMMONIUM CHLORIDE (TEACL). THE TEACL SYSTEM ABOLISHES THE PREFERENTIAL MELTING OF A-T VS. G-C BASE PAIRS IN DNA HYBRIDS, YIELDING A SIGNIFICANT SHARP-ENING OF THE MELTING PROFILE (<1C IN TEACL VS. 5-15C IN NACL), THUS ENHANCING PROBE SPECIFICITY. A DNA PROBE IN A TEACL SALT SYSTEM ALLOWS THE DEVELOPMENT OF A SENSITIVE AND SPECIFIC DNA PROBE ASSAY. THE LONG-TERM OBJECTIVE OF THE PROJECT IS TO PROVIDE A SIMPLE, RAPID, ACCURATE, AND LOW- COST METHOD FOR THE DETECTION OF CAMPYLOBACTER PYLORIDIS IN CLINICAL ISOLATES FROM PATIENTS WITH GASTRITIS OR PEPTIC ULCER. A DIAGNOSTIC TEST WILL BE PRODUCED COMMERCIALLY FOR BY CLINICAL DIAGNOSTIC LABORATORIES.