Rapid PCR detection of Helicobacter pylori-associated virulence and resistance genes directly from gastric biopsy material

Abstract

We have developed a PCR-based method to detect macrolide resistance and the virulence gene cagA in Helicobacter pylori within 24 h, thereby improving the lengthy process of culture-based approaches. Total DNA was prepared directly from stomach biopsy specimens. The procedure proved to be rapid and reliable and could be utilized for diagnostic purposes.

FIG. 1

Restriction enzyme digestions of samples from patients treated for H. pylori. Numbers denote patient samples; “a” lanes show digestion of the 23S rRNA gene with BsaI, and “b” lanes show digestion with MboII. Mw, 100-step basepair ladder (Pharmacia Biotech, Sollentuna, Sweden). The 700-bp band indicates a resistant strain, since the mutation site is in the middle of the 1.4-kb PCR fragment. Sample 1 was digested at 700 bp by both MboII and BsaI and thus mutated in both positions. Samples 2 and 3 were digested at the mutation by MboII; i.e., they had the A2143G mutation. Samples 4, 6, and 7 were digested by BsaI; i.e., they had the A2144G mutation. Sample 5 was not resistant.