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目的建立噬菌体Chy2生物扩增法,并评价其检测临床痰标本结核分枝杆菌的应用价值。方法噬菌斑测试法观察噬菌体杀灭剂灭活Chy2的工作浓度和作用时间;噬菌斑计数法判断Chy2的最佳感染时间和感染滴度;分别用噬菌体Chy2和D29生物扩增法检测58份临床痰标本,以改良罗氏培养法作诊断标准,对比评价Chy2和D29的检测准确性。结果 6%硫酸亚铁铵溶液作用5 min可彻底灭活游离Chy2;Chy2滴度为2.2×1011CFU/mL时,与结核分枝杆菌孵育4 h的感染效率最高;噬菌体Chy2生物扩增法对痰标本的检测灵敏度、特异性、Youden指数、阳性预测值和阴性预测值分别为94.7%、85.0%、0.797、0.923、0.895,噬菌体D29生物扩增法的检测结果相应为76.3%、95.0%、0.713、0.967、0.678,噬菌体Chy2生物扩增法的灵敏度、阴性预测值优于噬菌体D29生物扩增法(P<0.05),两者特异性、Youden指数、阳性预测值无统计学差异(P>0.05)。结论成功建立了噬菌体Chy2生物扩增法,Chy2较D29检测特异性相当,灵敏度有所提高。
Objective To establish a phage Chy2 bioassay and to evaluate its value in the detection of clinical sputum specimens of Mycobacterium tuberculosis. Methods The phage plaque assay was used to observe the working concentration and duration of inactivation of Chy2 by bacteriophage killing agent. The best infection time and infection titer of Chy2 were determined by plaque counting method. The biological amplification of Chy2 and D29 The clinical sputum specimens, modified Roche culture method for diagnostic criteria, comparative evaluation of Chy2 and D29 detection accuracy. Results 6% ferrous ammonium sulfate solution for 5 min completely inactivated free Chy2; Chy2 titer 2.2 × 1011CFU / mL, the highest efficiency of infection with Mycobacterium tuberculosis 4 h incubation; phage Chy2 biological amplification of sputum The detection sensitivity, specificity, Youden index, positive predictive value and negative predictive value were 94.7%, 85.0%, 0.797,0.923,0.895 respectively. The results of phage amplification assay D29 were 76.3%, 95.0%, 0.713 , 0.967,0.678 respectively. The sensitivity and negative predictive value of the phage Chy2 bioassay were better than those of the phage D29 bioassay (P <0.05). There was no significant difference in the Youden index and the positive predictive value (P> 0.05) ). Conclusion The phage Chy2 bioassay was successfully established. Chy2 was more specific and sensitive than D29.