OBJECTIVE: To probe into the mutation of drug resistance gene in 89 children with Helicobacter pylori （Hp） infection in Dongguan City Maternal and Children Health Hospital （hereinafter referred to as "our hospital"）.METHODS: 89 children with HP infection admitted into our hospital from Jan. 2017 to Jun. 2019 were selected. All the children were given triple therapy centered on PPI

namely Omeprazole sodium enteric-coated tablets + Amoxicillin clavulanate potassium granules+Clarithromycin tablets

the course of treatment was 2 weeks. The resistance of Hp isolated strains to clarithromycin and Amoxicillin clavulanate potassium was determined by PCR amplification reagents

the mutations of resistance genes of different drugs were analyzed

and the mutation rate was recorded. RESULTS: A total of 89 Hp strains were isolated

the resistance rates of clarithromycin and amoxicillin clavulanate potassium were respectively 17. 98% （16 strains） and 15. 73% （14 strains）. There was no statistical significance in difference in drug resistance rates of clarithromycin and amoxicillin clavulanate potassium between boys and girls （P > 0. 05）. The mutation rates of clarithromycin mutation sites A2142G

A2143G and T2182C were respectively 26. 97% （24/89）

3. 37% （3/89） and47. 19% （42/89）

with T2182C having the highest mutation rate. The mutation rates of amoxicillinclavulanate potassium mutation sites C1667G

A1684G and A1777G were respectively 4. 49% （4/89）

2. 25% （2/89） and 12. 36% （11/89）

with A1777G having the highest mutation rate. The mutation rates of A2142G and A2143G genes in children with drug resistance were respectively 91. 67% （22/24） and 100. 00% （3/3）

which were higher than 8. 33% （2/24） and 0 in sensitive children. CONCLUSIONS: The drug resistance rates of clarithromycin and amoxicillin clavulanate potassium are very close

and the mutation rates of A2142G and A2143G genes in children with drug resistant are higher than those in sensitive children.