新型国产改良Middlebrook液体培养试剂对结核分枝杆菌培养效果的评价

目的: 评价新型国产改良Middlebrook液体培养试剂用于临床样本中结核分枝杆菌培养的效果。方法: 采集2021年3—4月西安市胸科医院诊治的疑似肺结核患者痰液和肺泡灌洗液标本,对其中质量合格的89份痰液标本和61份肺泡灌洗液标本进行分枝杆菌改良试剂培养(改良试剂法)和BACTEC MGIT 960(简称“MGIT 960”)培养。比较两种方法检测分枝杆菌的阳性率、报阳时间和污染率差异,并以MGIT 960培养结果为参照标准,评价改良试剂法的检测效能。结果: 改良试剂法检测痰液和肺泡灌洗液标本结核分枝杆菌的总阳性率[44.7%(67/150)]和报阳时间[中位数(四分位数):13.0(8.5,17.0)d]与MGIT 960培养结果[分别为42.7%(63/150)和13.0(8.0,17.5)d]相比,差异均无统计学意义(χ²=0.571,P=0.453;Z=-1.344,P=0.179)。两种方法检测肺泡灌洗液标本均未出现污染,但改良试剂法检测痰液标本的污染率[12.4%(11/89)]明显高于MGIT 960培养[4.5%(4/89)],差异有统计学意义(χ²=4.000,P=0.039)。 改良培养试剂的成本[(49.6±10.5)元/份]仅约为MGIT 960培养试剂[(75.4±15.8)元/份]的60%。以MGIT 960培养结果为参照标准,改良试剂法检测痰液和肺泡灌洗液标本结核分枝杆菌的总敏感度为96.9%(62/64)、总特异度为94.2%(81/86),Kappa值为0.905,一致性好。结论: 分枝杆菌改良Middlebrook液体培养试剂检测痰液和肺泡灌洗液标本与MGIT 960培养诊断结核病的一致性好,但应注意痰液标本检测污染率较高的问题。

Evaluation of the effect of a new domestic improved Middlebrook liquid culture reagent on the culture of Mycobacterium tuberculosis

Objective:To evaluate the effect of a new domestic improved Middlebrook liquid culture reagent on the culture of Mycobacterium tuberculosis in clinical.Methods:Sputum and alveolar lavage fluid samples of suspected pulmonary tuberculosis patients diagnosed and treated in Xi’an Chest Hospital from March to April 2021 were collected.Eighty-nine sputum samples and 61 alveolar lavage fluid samples were qualified and cultured with mycobacterium modified reagent and BACTEC MGIT 960(MGIT 960).The positive rate,positive reporting time and contamination rate of mycobacterium detection by the two methods were compared,and the detection efficiency of the improved reagent method was evaluated refered to the culture results of MGIT 960.Results:The total positive rate and positive reporting time(median(quartile))of sputum and alveolar lavage fluid samples detected by mycobacterium modified reagent method were not significantly different from the culture results of MGIT 960(44.7%(67/150)vs.42.7%(63/150),χ²=0.571,P=0.453;13.0(8.5,17.0)d vs.13.0(8.0,17.5)d,Z=-1.344,P=0.179).There was no contamination in alveolar lavage fluid samples detected by the two methods,but the contamination rate of sputum samples detected by the improved reagent method(12.4%(11/89))was significantly higher than that of MGIT 960 culture(4.5%(4/89))(χ²=4.000,P=0.039).The cost of the improved culture reagent(RMB(49.6±10.5)yuan/person)was only about 60%of that of MGIT 960 culture reagent(RMB(75.4±15.8)yuan/person).Using MGIT 960 culture results as the standard,the total sensitivity and specificity of the improved reagent method for sputum and alveolar lavage fluid samples were 96.9%(62/64)and 94.2%(81/86),the Kappa value was 0.905,showing excellent consistency.Conclusion:Mycobacterium modified Middlebrook liquid culture reagent has the good consistency of MGIT 960 culture in the detection of sputum and alveolar lavage fluid,however,attention should be paid to the high contamination rate of sputum specimens.