江苏地区幽门螺杆菌对左氧氟沙星的耐药情况

An investigation on Helicobacter pylori resistence to levofloxacin in Jiangsu area

目的分析江苏地区幽门螺杆菌(Hp)对左氧氟沙星的耐药情况,探讨Hp对左氧氟沙星的耐药机制。方法慢性胃炎或消化性溃疡患者160例,将胃镜活检黏膜标本接种于Hp选择性培养基,37℃微需氧环境培养3-5d;分离Hp菌株,采用Giemsa染色、尿素酶试验和UreA基因PCR扩增鉴定菌种。左氧氟沙星药敏试验采用E试验(E-test),筛选出耐药菌株和敏感菌株。提取Hp菌株基因组DNA,PCR扩增gyrA基因并测序。结果 62例分离出Hp菌株,并行左氧氟沙星E-test药敏试验。其中,20例最低抑菌浓度(MIC)>1.0μg/ml,耐药菌株占32.25%,敏感菌株占67.75%。gyrA基因测序结果显示,20例耐药菌株261、271和272位点存在突变;C261A突变4例,C261G突变3例,G271A突变6例,A272G突变7例。而在40例敏感菌株中未发现突变。结论江苏地区分离Hp的临床菌株左氧氟沙星耐药率较高。其耐药与gyrA基因261、271和272位点有关。

Objective To analyze the Helicobacter pylori （Hp） resistance to levofloxacin in Jiangsu province and explore the mechanism for it. Methods The gastric mucosa samples from 160 patients with chronic gastritis and/or peptic ulcer taken by gastroendoscopy were put into selective medium for Hp and cultured with microoxegen enviralment for 3 to 5 days. Hp was identified by Giemsa stain, urease test and PCR reaction test. The levofloxacin-resistant and -sensitive strains were screened. The Hp DNA was extracted, amplified and sequenced. Results Of 160 samples, Hp was isolated and E-test of resistance to levofloxzcin was performed in 62 samples, of which 20 had a minimum inhibition concentration （MIC） higher than 1.0μg/ml with the drug-resistant strain of 32.25% and drug-sensitive strain of 67.75%. The sequening of gyrA shown that the mutation existed at 261,271,272 locus in 20 drug-resistant strains, which included 4 mutations in C261A, 3 in C261G, 6 in G271A and 7 in A272G. The mutation was not found in 40 drug-sensitive strains. Conclusion The isolated strains of Hp in Jiangsu province has a high rate of drug resistance to levofloxacin, which is related to the mutations at 261,271 ,and 272 locus of gyrA gene.