Tarrand J J, Gröschel D H
J Clin Microbiol. 1985 Jun;21(6):941-6. doi: 10.1128/jcm.21.6.941-946.1985.
BACTEC and conventional methods of antimicrobial susceptibility testing were compared with the use of artificial mixtures of 1% resistant and 99% susceptible Mycobacterium tuberculosis strains. Inocula for the assays were prepared on the basis of radiometric readings. A total of 40 resistant strains were tested: 18 were resistant to isoniazid, 16 to rifampin, 5 to streptomycin, and 1 to ethambutol. The BACTEC method detected 27 of 39 strains at the greater than 0.5% resistance level, whereas the conventional plate method detected only 8 of 40. In addition, the results of the BACTEC assay were closer to the expected 1% resistance level (0.7%) than were the data obtained with the proportional plate method (0.3%; P = 0.001). This difference was most striking with the isoniazid-resistant strains. The precision of the assay methods was quite different (coefficients of variation, 26% for BACTEC and 54% for plates; P = 0.0002). Streptomycin-resistant strains had the highest variability in both assay methods. A 1-day delay in calculating the BACTEC data after the control vial reading was equal to or greater than 30 resulted in a 25% reduction in the calculated level of resistance (0.7 to 0.53). By adhering exactly to the recommended procedures for the BACTEC test method and by using log-phase inocula, this method shows better precision and accuracy at the 1% resistance level than does the proportional plate method.
使用1%耐药和99%敏感的结核分枝杆菌菌株的人工混合物，比较了BACTEC法和传统抗菌药敏试验方法。根据放射性测量读数制备检测接种物。共检测了40株耐药菌株：18株对异烟肼耐药，16株对利福平耐药，5株对链霉素耐药，1株对乙胺丁醇耐药。BACTEC法在大于0.5%的耐药水平下检测出39株中的27株，而传统平板法在40株中仅检测出8株。此外，BACTEC检测结果比比例平板法获得的数据（0.3%；P = 0.001）更接近预期的1%耐药水平（0.7%）。这种差异在异烟肼耐药菌株中最为明显。两种检测方法的精密度差异很大（变异系数，BACTEC为26%，平板法为54%；P = 0.0002）。在两种检测方法中，链霉素耐药菌株的变异性最高。在对照瓶读数后1天延迟计算BACTEC数据，当读数等于或大于30时，计算出的耐药水平降低25%（从0.7降至0.53）。通过严格遵守BACTEC检测方法的推荐程序并使用对数期接种物，该方法在1%耐药水平下比比例平板法显示出更好的精密度和准确性。
