摘要
目的探讨甲硝唑耐药幽门螺杆菌(Hp)的rdx A基因突变的分子特征,分析疾病及细菌毒力基因变异对耐药的影响。方法从胃窦粘膜标本分离培养Hp,用琼脂稀释法药敏实验检测Hp对甲硝唑的敏感性;用PCR扩增Hp甲硝唑耐药基因rdx A、毒力基因cag A和vac A,PCR产物直接测序后进行序列比对分析。结果共分离出101株Hp,耐药株占43.6%,胃癌相关Hp菌株甲硝唑耐药率(33.3%)显著低于胃炎相关菌株(55.3%),差异有统计学意义(χ2=4.94,P=0.029);Hp毒力基因分型(cag A+/-、vac A各亚型)在敏感株和耐药株中的分布差异无统计学意义;序列分析表明,95.5%的Hp甲硝唑耐药株由插入/缺失核苷酸序列导致移码突变造成rdx A基因失活,59.1%的插入/缺失突变发生在单核苷酸重复序列位置。结论 rdx A的单核苷酸串联重复序列区域发生插入/缺失是引起基因突变失活,导致Hp甲硝唑耐药的主要机制。
Objective To investigate the molecular features and influencing factors of rdx A mutation in metronidazole-resistant Helicobacter pylori（ H. pylori）. Methods H. pylori was isolated from mucosal biopsies of gastric antrum,and the susceptibility of H. pylori to metronidazole was determined by the agar diffusion test. The rdx A gene responsible for the metronidazole-resistant,and virulence genes cag A and vac A were amplified using PCR,and the products were directly sequenced and analyzed. Results A total of 101 isolates of H. pylori were obtained,and the metronidazole-resistant isolates accounted for 43. 6%. The metronidazole-resistant rate in gastric cancer associated isolates was significantly lower than that in chronic gastritis associated isolates（ 33. 3% vs 55. 3%,χ2= 4. 94,P = 0. 029）. There was no statistical difference in the positive rate of cag A＋ /-gene and distribution of vac A subtypes between the metronidazole-resistant and metronidazole-sensitive isolates. Sequence analysis of rdx A gene showed that the inactivation of rdx A gene was caused by insertion / deletion-induced frameshift mutation in 95. 5% of metronidazole-resistant isolates,and that 59. 1% of insertion /deletion mutations occurred at the location of mononucleotide repeated sequence. Conclusion The inactivation ofrdx Agene caused by insertion / deletion mutations located in mononucleotide tandem repetitive sequence may be the main mechanism of metronidazole-resistant H. pylori.
出处
《临床检验杂志》
CAS
CSCD
2015年第7期494-497,共4页
Chinese Journal of Clinical Laboratory Science
基金
青岛市科技计划基础研究项目(13-1-4136-jch)
作者简介
王莉莉，1979年生，女，主治医师，博士，从事微生物耐药机制研究。
通信作者：孙桂荣，教授，博士研究生导师，E-mail：sungr@qduhospital．cn。
