OBJECTIVEIn order to understand the prevalence of hepatitis B virus (HBV) precore mutants isolated from asymtomatic carriers in Guangxi.

METHODSNested polymerase chain reaction (nPCR) was used for amplification of HBV DNA precore in 77 carrier sera, followed by HBV DNA nPCR products sequencing using direct sequencing.

RESULTS50.7% of 77 carriers was positive for HBV DNA with a prevalence of mutants 22.1% (17/77). HBV DNA positive rate in the southern part of the autonomous region was 55.6% (20/36). Six of them were mutants, counting for 30%. The common mutation in the southern part was seen T-->C at nt1858 while nt1896 stop mutation was discovered in one sample only, which was accompanied by point mutation at nt1837 (A-->G). HBV DNA positive rate in the northern part was 46.3% (19/41) with 11 of them were mutants, counting for 57.9%. The common mutation in that area stopped at nt1896. Among samples with stopped mutation, 4 samples had mutation at nt1846 (A-->T), 2 samples at nt1862 (G-->T). Both mutation at nt1856 (C-->T) and nt1858 (T-->C) could be seen in sample 734.

CONCLUSIONSThe prevalence of HBV precore mutant in asymptomatic carriers in Guangxi was at the average level in China. Further study is needed to determine the difference between the southern and the northern part of the region in the common type of mutation exists.