A PCR-OLIGONUCLEOTIDE LIGATION ASSAY TO DETERMINE THE PREVALENCE OF 23S RIBOSOMAL-RNA GENE-MUTATIONS IN CLARITHROMYCIN-RESISTANT HELICOBACTER-PYLORI

We have developed a rapid PCR-oligonucleotide ligation assay that can discriminate single base substitutions that are associated with clarit hromycin resistance in Helicobacter pylori. Susceptible isolates were wild type at positions 2143 and 2144 (cognate to 2058 and 2059 in Esch erichia coli), while 93% of the resistant isolates contained A-to-G mu tations at either position and 7% of the isolates contained A-to-C mut ations at position 2143. In addition, the MIC for 86% of the resistant isolates with an A2143 mutation was greater than or equal to 64 mu g per mi, and that for 89% of the resistant isolates with an A2144 mutat ion was less than or equal to 32 mu g per mi.