Zhen-Hua Zhu, De-Qiang Huang, Yong Xie, Lin-Lin Liu, Nong-Hua Lu
Department of Gastroenterology, The First Affiliated Hospital, Nanchang University, Nanchang, China.
Turk J Gastroenterol. 2013;24(1):5-9. doi: 10.4318/tjg.2013.0525.
BACKGROUND/AIMS: Clarithromycin is an effective antibiotic for treating Helicobacter pylori; however, the development clarithromycin- resistance by multiple strains prevents the eradication of Helicobacter pylori. We aimed to characterize mutations in the 23S rRNA gene of primary clarithromycin-sensitive, primary clarithromycin-resistant and secondary clarithromycin-resistant Helicobacter pylori strains that were collected in East China and elucidate the mechanisms of clarithromycin resistance.
The disk diffusion test and E-test method were used to determine the clarithromycin susceptibility of clinical Helicobacter pylori strains. The 23S rRNA gene fragments were amplified by polymerase chain reaction from 18 primary clarithromycin- resistant strains, 15 primary sensitive strains and 8 secondary clarithromycin-resistant strains. Polymerase chain reaction-products were sequenced to determine mutations of the 23S rRNA gene.
We found an A2143G (8 strains) mutation in primary clarithromycin-resistant strains, an A2143T (5 strains) mutation in secondary clarithromycin-resistant strains; but no mutations were found in position 2143 of sensitive strains. A T2182C mutation in primary clarithromycin-sensitive, primary clarithromycinresistant and secondary clarithromycin-resistant strains was found with a prevalence of 86.7% (13 strains), 72.2% (13 strains) or 87.5% (7 strains), respectively. In addition, we found a G2254T (8 strains) and a G2172T (7 strains) mutation in secondary clarithromycin- resistant strains. These point mutations were absent in primary clarithromycin-resistant and -sensitive strains.
The gene mutation in position 2143 was associated with resistance to clarithromycin, but the mutation was different between primary and secondary clarithromycin-resistant strains. The T2182C mutation was not associated with clarithromycin resistance. Two new hotspot mutations: G2254T and G2172T, in 23S rRNA were discovered in secondary clarithromycin-resistant strains.
背景/目的：克拉霉素是治疗幽门螺杆菌的有效抗生素；然而，多种菌株对克拉霉素产生耐药性阻碍了幽门螺杆菌的根除。我们旨在对华东地区收集的原发性克拉霉素敏感、原发性克拉霉素耐药和继发性克拉霉素耐药幽门螺杆菌菌株的23S rRNA基因中的突变进行特征分析，并阐明克拉霉素耐药机制。
采用纸片扩散法和E-test法测定临床幽门螺杆菌菌株对克拉霉素的敏感性。通过聚合酶链反应从18株原发性克拉霉素耐药菌株、15株原发性敏感菌株和8株继发性克拉霉素耐药菌株中扩增23S rRNA基因片段。对聚合酶链反应产物进行测序以确定23S rRNA基因的突变。
我们在原发性克拉霉素耐药菌株中发现了A2143G突变（8株），在继发性克拉霉素耐药菌株中发现了A2143T突变（5株）；但在敏感菌株的2143位点未发现突变。在原发性克拉霉素敏感、原发性克拉霉素耐药和继发性克拉霉素耐药菌株中均发现了T2182C突变，其发生率分别为86.7%（13株）、72.2%（13株）或87.5%（7株）。此外，我们在继发性克拉霉素耐药菌株中发现了G2254T突变（8株）和G2172T突变（7株）。这些点突变在原发性克拉霉素耐药和敏感菌株中不存在。
2143位点的基因突变与对克拉霉素的耐药性有关，但原发性和继发性克拉霉素耐药菌株中的突变不同。T2182C突变与克拉霉素耐药性无关。在继发性克拉霉素耐药菌株中发现了23S rRNA中的两个新的热点突变：G2254T和G217
