The comparison of YMDD mutation results detected by direct sequencing and real-time PCR / 解放军医学杂志

ABSTRACT

Objective To compare the efficiency of detecting YMDD mutations by direct DNA sequencing and real time fluerescence PCR, and to explore the significance of the mutations of drug-resistance gene other than YMDD mutation. Methods 92 serum samples from 89 patients with chronic hepatitis B were collected and all the samples were detected by real-time PCR for YMDD mutation. HBV DNA was extracted from serum and was amplified by nest PCR to achieve HBV P gene RT region sequence. The PCR products were sequenced at both directions, and the sequencing results were contrasted through NTI program. The other 11 known drug-resistance mutation sites at the HBV RT region were also analyzed. Results Among the 37 samples with no YMDD mutation detected by real-time PCR, 33 samples were with M204M (without mutation), 1 sample with M204I and 3 samples with M204V by direct sequencing. Mutation and wild-type standard sequences were all coexisted in the 4 positive samples. There were 7 samples detected with ADV resistant mutation, accounting for 18.9% (7/37). Among the 55 samples with YMDD mutation detected by real-time PCR, 52 samples were detected by DNA sequencing, the accordance rate was 94.5% (52/55); 5 samples with ADV or ETV resistant mutation were detected, accounting for 9.1% (5/55). Conclusions Direct DNA sequencing is a high sensitive, repeatable method to detect drug-resistance mutation at RT region of HBV P gene. The result is well consistent with that attained by real-time PCR. Direct DNA sequencing can also detect various drug-resistance mutations as well as YMDD mutation, which is helpful to generally understand the nucleoside analogue resistant mutation and adopt more reasonable therapy projects against HBV.