Barry A L, Thornsberry C, Jones R N, Gerlach E H
Antimicrob Agents Chemother. 1980 Oct;18(4):616-21. doi: 10.1128/AAC.18.4.616.
Disk susceptibility tests with two structurally related aminoglycosides (amikacin and Sch 21420) were evaluated. Tests with 10- and 30-micrograms amikacin disks confirmed previous recommendations for interpretive zone standards; 30-micrograms disks are preferred. Tests with 10-, 20-, and 30-micrograms Sch 21420 disks led to similar conclusions. The 30-micrograms Sch 21420 disks are recommended, with zone standards of less than or equal to 14 mm for the resistant category (minimal inhibitory concentration, greater than or equal to 32 micrograms/ml) and greater than or equal to 17 mm for the susceptible category (minimal inhibitory concentration, less than or equal to 16 micrograms/ml). If a minimal inhibitory concentration breakpoint of less than or equal to 8 micrograms/ml is preferred for defining the susceptible category, somewhat different zone standards may be used (less than or equal to 15 mm and greater than or equal to 19mm). Further evaluation documented the fact that tests with 30-micrograms amikacin disks predicted resistance or susceptibility to Sch 21420 almost as well as did a 30-micrograms Sch 21420 disk. Thus, the class concept of disk testing was judged to applicable, and routine testing with Sch 21420 may not be required.
对两种结构相关的氨基糖苷类药物（阿米卡星和Sch 21420）进行了纸片药敏试验评估。用含10微克和30微克阿米卡星的纸片进行的试验证实了先前关于解释性抑菌圈标准的建议；首选30微克的纸片。用含10微克、20微克和30微克Sch 21420的纸片进行的试验得出了类似结论。推荐使用30微克Sch 21420纸片，耐药类别（最低抑菌浓度大于或等于32微克/毫升）的抑菌圈标准为小于或等于14毫米，敏感类别（最低抑菌浓度小于或等于16微克/毫升）的抑菌圈标准为大于或等于17毫米。如果将敏感类别的最低抑菌浓度断点定义为小于或等于8微克/毫升，则可使用略有不同的抑菌圈标准（小于或等于15毫米和大于或等于19毫米）。进一步评估证明，用30微克阿米卡星纸片进行的试验预测对Sch 21420耐药或敏感的效果几乎与用30微克Sch 21420纸片进行的试验相同。因此，纸片试验的类别概念被判定适用，可能不需要常规进行Sch 21420试验。
