Department of Laboratory Sciences, School of Paramedical Sciences, Torbat Heydariyeh University of Medical sciences, Torbat Heydariyeh, Iran.
Department of Bacteriology, Pasteur Institute of Iran, Tehran, Iran.
Helicobacter. 2020 Apr;25(2):e12684. doi: 10.1111/hel.12684. Epub 2020 Feb 19.
Resistant Helicobacter pylori to commonly used antimicrobial agents are associated with severe upper gastrointestinal disorders. To provide an epidemiological picture of H pylori and characterize the resistance pattern and genetic variation of clinical isolates, stomach biopsies from patients with functional dyspepsia were evaluated in northeast of Iran.
In this study, 80 patients were recruited. Finally, fifty H pylori strains were isolated from antrum and corpus biopsies by culturing on Columbia agar. All strains were identified by standard laboratory procedures. Susceptibility testing of antibiotics was performed using minimum inhibitory concentration test. Allele-specific primer (ASP)-PCR of 23S rRNA which associated with clarithromycin resistance was done among resistant strains. Moreover, cagA gene and polymorphism in vacA were detected. Random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) was applied to investigate the genetic variations among all strains.
Antibiotic resistance pattern of H pylori strains was as follows: 68% (34/50) to metronidazole, 50% (25/50) to rifampicin, 30% (15/50) to amoxicillin, 28% (14/50) to levofloxacin, 22% (11/50) to clarithromycin, and 16% (8/50) to tetracycline. Multidrug-resistant strains were observed in 19 strains (38%). ASP-PCR of 23S rRNA showed four strains had A2143G mutation, six strains had A2142G mutation, and one strain had a Wt+A2143G mutation. Amplification of virulence-associated genes revealed that cagA was present in 27 isolates (54%) and vacA in 36 isolates (72%). The most common genotype of H pylori was vacA s1am2 (40%) followed by vacA s2m2 (14%), vacA s1am1 (12%), vacA s1bm1 (4%), and vacA s1bm2 (2%). DNA fingerprinting pattern indicated a high heterogeneity among isolated strains.
An alarming level of resistance to metronidazole and rifampicin and high heterogeneity among H pylori isolates highlighted the importance of continued monitoring of antimicrobial susceptibility and epidemiological surveillance of this pathogen.
耐常用抗菌药物的幽门螺杆菌与严重的上消化道疾病有关。为了提供幽门螺杆菌的流行病学图片，并描述临床分离株的耐药模式和遗传变异，对伊朗东北部功能性消化不良患者的胃活检进行了评估。
本研究共招募了 80 名患者。最终，从胃窦和胃体活检中培养出 50 株幽门螺杆菌。所有菌株均通过标准实验室程序鉴定。采用最低抑菌浓度试验对抗生素进行药敏试验。对耐药菌株进行 23S rRNA 等位基因特异性引物（ASP）-PCR，以检测与克拉霉素耐药相关的突变。此外，还检测了 cagA 基因和 vacA 多态性。应用随机扩增多态性 DNA 聚合酶链反应（RAPD-PCR）检测所有菌株的遗传变异。
幽门螺杆菌菌株的抗生素耐药模式如下：68%（34/50）对甲硝唑耐药，50%（25/50）对利福平耐药，30%（15/50）对阿莫西林耐药，28%（14/50）对左氧氟沙星耐药，22%（11/50）对克拉霉素耐药，16%（8/50）对四环素耐药。19 株（38%）为多药耐药菌株。23S rRNA 的 ASP-PCR 显示 4 株有 A2143G 突变，6 株有 A2142G 突变，1 株有 Wt+A2143G 突变。毒力相关基因的扩增显示 cagA 存在于 27 株（54%）中，vacA 存在于 36 株（72%）中。幽门螺杆菌最常见的基因型是 vacA s1am2（40%），其次是 vacA s2m2（14%）、vacA s1am1（12%）、vacA s1bm1（4%）和 vacA s1bm2（2%）。DNA 指纹图谱显示分离株之间存在高度异质性。
对甲硝唑和利福平的耐药率令人担忧，以及幽门螺杆菌分离株之间的高度异质性，强调了继续监测抗菌药物敏感性和该病原体的流行病学监测的重要性。
