摘要
目的:探讨幽门螺杆菌(Helicobacter pylori,Hp)对克拉霉素耐药的分子基础。方法:采用E-test方法对35例Hp的临床分离株进行克拉霉素的MIC(minimal inhibitory concentration)检测,大于或等于8mg/L为耐药株, 按酚-氯仿方法提取Hp的DNA,PCR方法扩增23S rRNA基因中2047-2347之间的片段,对PCR产物进行序列分析,观察耐药株的基因突变情况,结果:与敏感菌(No33)序列比较,No13存在1个突变位点,即2289位点T变成了C(T2289C),No17存在2个突变位点,即G2224A、T2289C,No22存在3个突变位点,即G2224A、C2245T及T2289C,三株耐药Hp菌株的MIC值分别是:No13为8.0mg/L,No17为64mg/L,No22为大于256mg/L,随着耐药性的提高(表现在MIC值的升高),高耐药性菌株的突变位点多于低耐药注菌株的突变位点结论:与耐药有关的3个突变位点,G2224A、C2245T及T2289C,国内外未见报道。
AIM: To investigate the resistance mechanism of Hp to darithromycin. METHODS: With E-test method, we examined the minimal inhibitory concentration (MIC) to clarithromycin of 35 Hp dinical isolates. Resistance strains were defined when MIC ≥ 8 mg/L. Extract the DNA from the bacteria with the phenol- chloroform extraction method. Then amplify the fragments from 2 047 to 2 347 of 23 S rRNA gene. Gene sequence of the FCR products was analyzed to observe the mutation in the resistant Hp strains. RESULTS: Compared with susceptible strains, No13 strain contained one point mutation (T2289C), No17 had two point mutations (G2224A, T2289C) and No22 strain had 3 point mutations (G2224A, C2245T, T2289C). The MICs of the 3 resistant Hpisolates were as follows: No13 of 8.0 mg/L, No17 of 64 mg/L, No22 of > 256 mg/L. With increase of the resistance of Hp strains, the number of point mutations increased. C0NCLUSION: The point-mutations at 23 S rRNA gene re- spensible for Hp resistance to clarithromycin have not been reported in literature either at home or abroad, demon- strating that different mechanism of Hp resistance to clarithromvcin exists in different regions.
出处
《世界华人消化杂志》
CAS
2003年第10期1485-1487,共3页
World Chinese Journal of Digestology
