Simultaneous colonisation of Helicobacter pylori with and without mutations in the 23S rRNA gene in patients with no history of clarithromycin exposure
Simultaneous colonisation of Helicobacter pylori with and without mutations in the 23S rRNA gene in patients with no history of clarithromycin exposure
复制标题
在无克拉霉素暴露史的患者中，有或没有 23S rRNA 基因突变的幽门螺杆菌同时定植
作者：
Masaki Matsuoka;Y. Yoshida;K. Hayakawa;S. Fukuchi;K. Sugano
最近有报道称，幽门螺杆菌23S rRNA基因2143和2144位的A到G过渡突变与克拉霉素耐药有关。目的通过对克拉霉素耐药突变的分析，探讨克拉霉素耐药的发生及发生机制。对象：82例幽门螺杆菌阳性患者，经内窥镜检查，无大环内酯类抗生素治疗史。方法采用聚合酶链反应- 23S rRNA基因限制性片段长度多态性结合药敏试验筛选克拉霉素耐药性。在具有突变或耐药的临床分离株中，通过直接测序分析单个菌落的突变。结果在79个扩增子（聚合酶链反应扩增的DNA片段）中，Alw26I和MboII酶切分别在4个（5%）和1个（1%）中发现突变。然而，在四个扩增子中的两个中，Alw26I的切割是不完整的，就像theMboII的切割一样。对裂解模式不完全的分离株进行菌落分析，发现23S rRNA基因同时存在野生型和突变株。结论：在一些没有大环内酯类药物暴露史的患者中，克拉霉素敏感菌株和耐药菌株均有定植。结果表明，耐药菌株可能不是由克拉霉素引起的，而是由克拉霉素引起的。
BACKGROUND It was recently reported that A to G transition mutations at positions 2143 and 2144 in the 23S rRNA gene are associated with clarithromycin resistance in Helicobacter pylori. AIMS To study the incidence and mechanism of development of clarithromycin resistance by analysing these mutations. SUBJECTS Eighty twoH pylori positive patients who had an endoscopic examination and no history of treatment with macrolide antibiotics. METHODS Clarithromycin resistance was screened for by polymerase chain reaction-restriction fragment length polymorphism of the 23S rRNA gene coupled with antibiotic susceptibility testing. In clinical isolates with mutations or resistance, mutations in individual colonies were analysed by direct sequencing. RESULTS Of the 79 amplicons (DNA fragments amplified by polymerase chain reaction),Alw26I and MboII digestion disclosed the mutation in four (5%) and one (1%) respectively. However, the Alw26I cleavage was incomplete in two of the four amplicons, as was theMboII cleavage. Individual colony analysis of the isolates with incomplete cleavage patterns showed the presence of both wild type and mutated strains in the 23S rRNA genes. CONCLUSIONS Both clarithromycin sensitive and resistant strains colonised in some patients with no history of exposure to macrolides. The results suggest that resistant strains may not be formed but selected by clarithromycin administration.