Hachem C Y, Clarridge J E, Reddy R, Flamm R, Evans D G, Tanaka S K, Graham D Y
Department of Medicine, Veterans Affairs Medical Center, Houston, TX 77030, USA.
Diagn Microbiol Infect Dis. 1996 Jan;24(1):37-41. doi: 10.1016/0732-8893(95)00252-9.
The optimal method for the determination of the minimum inhibitory concentration (MIC) of antimicrobials against Helicobacter pylori has not been established. The epsilometer agar diffusion gradient test (E-Test; AB Biodisk, Solna, Sweden) was compared with broth microdilution, the reference method, and disk diffusion for the antimicrobial susceptibility testing of 122 clinical isolates of H. pylori to ampicillin, clarithromycin, and metronidazole. Isolates were considered to be resistant when the MIC values was > 8 micrograms/ml for either ampicillin or metronidazole and > 2 micrograms/ml for clarithromycin. For an individual isolate, the MICs for ampicillin and clarithromycin determined by broth microdilution and the E-test were highly reproducible, with replicate results being within +/- 1 log2 dilution. The correlation between the MICs determined by E-test and broth microdilution was excellent for both ampicillin and clarithromycin (90.1% and 88.5% were within +/- log2 dilution, and 98.3% and 96.7% of the values were within +/- 2 log2 dilution, respectively). In no instance did the interpretation of "sensitive" or "resistant" differ. Conversely, only 70.5% of the E-test results of metronidazole were within +/- 1 log2 dilution of the broth microdilution results. In addition, 15 (12.3%) of the H. pylori isolates interpreted as resistant by the E-test were sensitive by the broth microdilution method. All discrepancies occurred when the E-test MIC values fell between 8 and 32 micrograms/ml. The results of the ampicillin and clarithromycin disk diffusion assay correlated 100% with the results of the broth microdilution. However, these data suggest that when the E-test MIC results of metronidazole yield values between 8 and 32 micrograms/ml, the MIC should be reevaluated by another method.
尚未确定针对幽门螺杆菌测定抗菌药物最低抑菌浓度（MIC）的最佳方法。将埃普利米特琼脂扩散梯度试验（E试验；AB生物盘公司，瑞典索尔纳）与作为参考方法的肉汤微量稀释法以及纸片扩散法进行比较，以检测122株幽门螺杆菌临床分离株对氨苄西林、克拉霉素和甲硝唑的药敏情况。当氨苄西林或甲硝唑的MIC值>8微克/毫升且克拉霉素的MIC值>2微克/毫升时，分离株被视为耐药。对于单个分离株，通过肉汤微量稀释法和E试验测定的氨苄西林和克拉霉素的MIC具有高度可重复性，重复结果在±1个对数2稀释范围内。E试验和肉汤微量稀释法测定的氨苄西林和克拉霉素的MIC之间的相关性极佳（分别有90.1%和88.5%在±1个对数2稀释范围内，98.3%和96.7%的值在±2个对数2稀释范围内）。在任何情况下，“敏感”或“耐药”的判定均无差异。相反，甲硝唑的E试验结果仅有70.5%在肉汤微量稀释结果的±1个对数2稀释范围内。此外，通过E试验判定为耐药的幽门螺杆菌分离株中有15株（12.3%）通过肉汤微量稀释法检测为敏感。所有差异均发生在E试验的MIC值介于8至32微克/毫升之间时。氨苄西林和克拉霉素纸片扩散试验的结果与肉汤微量稀释法的结果100%相关。然而，这些数据表明，当甲硝唑的E试验MIC结果在8至32微克/毫升之间时，应通过另一种方法重新评估MIC。
