Madison B, Gross W, George I, Sloutsky A, Washabaugh G, Robinson-Dunn B, Lipman H, Metchock B, Mazurek G, Ridderhof J
Centers for Disease Control and Prevention, 4770 Buford Highway NE, Mail Stop G-25, Atlanta, GA 30347, USA.
J Clin Microbiol. 2002 Oct;40(10):3753-6. doi: 10.1128/JCM.40.10.3753-3756.2002.
Pyrazinamide (PZA) is an integral component of the short-course chemotherapy regimen for tuberculosis. The BACTEC 460TB PZA susceptibility test for Mycobacterium tuberculosis with a daily (D) reading schedule has been available for more than 10 years, but weekend laboratory staffing is necessary. A nonweekend (NW) reading schedule has not been validated in a multicenter study. This prospective multicenter study compares the interlaboratory reproducibility of PZA susceptibility results by following both the D and NW schedules. A total of 181 cultures were shared among four laboratories. Isolates were selected based on resistance or borderline resistance to at least one streptomycin-isoniazid-rifampin-ethambutol drug or PZA. One laboratory used a D reading schedule, and three laboratories used a NW schedule. Both reading schedules are based on the standard BACTEC 460TB PZA protocol. With the NW schedule, the growth index (GI) is not available for test interpretation on Saturday, Sunday, and Monday. Of the 181 shared cultures, 154 were found to be susceptible by all laboratories, 19 were found to be resistant, and 8 had discordant results. The overall pairwise interlaboratory agreement was 97.7%. The discrepancies were not associated with the type of reading schedule used. However, the median control GI was significantly higher for the NW schedule (321) than for the D schedule (259) (P < 0.0001) although results were available on average in about 7 days from setup for both schedules. These results show that the NW schedule is a suitable alternative for laboratories that do not read and interpret PZA susceptibility tests on weekends.
吡嗪酰胺（PZA）是结核病短程化疗方案的一个重要组成部分。用于结核分枝杆菌的BACTEC 460TB PZA药敏试验，每日（D）读数方案已应用超过10年，但周末需要实验室工作人员值班。非周末（NW）读数方案尚未在多中心研究中得到验证。这项前瞻性多中心研究通过遵循D和NW方案比较了PZA药敏结果的实验室间重复性。四个实验室共分享了181株培养物。根据对至少一种链霉素-异烟肼-利福平-乙胺丁醇药物或PZA的耐药或临界耐药情况选择分离株。一个实验室采用D读数方案，三个实验室采用NW方案。两种读数方案均基于标准的BACTEC 460TB PZA方案。采用NW方案时，周六、周日和周一无法获得生长指数（GI）用于试验判读。在181株共享培养物中，所有实验室均发现154株敏感，19株耐药，8株结果不一致。实验室间总体两两一致性为97.7%。差异与所采用的读数方案类型无关。然而，NW方案的对照GI中位数（321）显著高于D方案（259）（P<0.0001），尽管两种方案从接种开始平均约7天可获得结果。这些结果表明，对于不在周末进行PZA药敏试验判读的实验室，NW方案是一种合适的替代方案。
