Objective:To investigate the prevalence and resistance mechanism of Helicobacter pylori(Hp) resistant to Clarithromycin in Chongqing area.Methods:96 Hp clinical isolates were cultured.The susceptibilities of the 96 Hp strains to clarithromycin were tested by agar dilution test to determine minimum inhibitory concentration(MIC).These Hp strains with MIC>2 μg/ml were defined to be resistant to clarithromycin

then prevalence of Hp resistant to Clarithromycin in urban and rural area of Chongqing were compared.10 Hp strains of being resistant to Clarithromycin were chosen.After the DNAs of Hp were extracted

PCR-Restriction Fragment Length Polymorphism(RFLP) analysis was used to test 23SrRNA domain V gene mutations.Results:The resistance rate of Hp resistant to Clarithromycin in Chongqing area was 29.17%

with no statistically significant difference between urban and rural area(P>0.05).10 clarithromycin-resistant stains of Hp were found to have an A-to-G mutation in 23SrRNA domain V at position of 2143.Conclusions:The results indicated that prevalence of Hp resistant to Clarithromycin in Chongqing area was higher

and there was no statistically significant difference between urban and rural area(P>0.05).Besides

the majority of clarithromycin-resistant isolates of Hp in Chongqing have an A2143G mutation in 23SrRNA domain V.