Vasquez A, Valdez Y, Gilman R H, McDonald J J, Westblom T U, Berg D, Mayta H, Gutierrez V
Department of Pathology, Universidad Peruana Cayetano Heredia, Lima, Peru.
J Clin Microbiol. 1996 May;34(5):1232-4. doi: 10.1128/jcm.34.5.1232-1234.1996.
Resistance of Helicobacter pylori to metronidazole often causes failure of commonly used combination drug treatment regimens. We determined the MICs of metronidazole and clarithromycin against 18 H. pylori strains from Peru using tetrazolium egg yolk (TEY) agar. The MIC results obtained by agar dilution with petri dishes were compared with the results found through a miniwell format. The results of the two protocols for measuring drug susceptibility differed by no more than 1 dilution in all cases. On TEY agar, bright-red H. pylori colonies were easy to identify against a yellow background. Sixty-one percent (11 of 18) of the strains were resistant to metronidazole (MIC, > or = 4 micrograms/ml) and 50% (9 of 18) were resistant to clarithromycin (MIC, > or = 0.125 micrograms/ml), whereas none (0 of 5) of the strains tested were resistant to tetracycline (MIC, > or = 1 micrograms/ml). Thus, the prevalence of metronidazole and clarithromycin resistance in Peru is higher than that in developed regions of the world. The miniwell plate with TEY agar allows easy H. pylori colony identification, requires about one-third less of the costly medium necessary for petri dish assaying, conserves space, and yields MICs equivalent to those with agar dilution in petri dishes.
幽门螺杆菌对甲硝唑的耐药性常常导致常用联合药物治疗方案失败。我们使用四氮唑蛋黄（TEY）琼脂测定了18株来自秘鲁的幽门螺杆菌对甲硝唑和克拉霉素的最低抑菌浓度（MIC）。将用培养皿进行琼脂稀释法获得的MIC结果与通过微孔板法得到的结果进行比较。在所有情况下，两种测量药物敏感性方案的结果差异不超过1个稀释度。在TEY琼脂上，鲜红色的幽门螺杆菌菌落相对于黄色背景易于识别。61%（18株中的11株）的菌株对甲硝唑耐药（MIC，≥4微克/毫升），50%（18株中的9株）对克拉霉素耐药（MIC，≥0.125微克/毫升），而所测试的菌株中无一（5株中的0株）对四环素耐药（MIC，≥1微克/毫升）。因此，秘鲁甲硝唑和克拉霉素耐药的流行率高于世界发达地区。带有TEY琼脂的微孔板便于识别幽门螺杆菌菌落，所需成本高昂的培养基比培养皿检测少约三分之一，节省空间，并且产生的MIC与培养皿琼脂稀释法相当。
