4种不同方法检测痰液及支气管肺泡灌洗液中结核分枝杆菌阳性率的比较分析

Comparative analysis on four different methods for testing the positive rate of mycobacterium tuberculosis in sputum and bronchoalveolar lavage fluid

目的比较4种不同方法检测痰液和支气管肺泡灌洗液(bronchoalveolar lavage fluid,BALF)样本中结核分枝杆菌(mycobacterium tuberculosis,MTB)的阳性检出率差异,并评估其在肺结核诊断中的临床价值。方法收集2018年1月至6月在河北省胸科医院就诊的415例肺结核患者的BALF及痰液,分别应用夹层杯离心集菌涂片法(涂片法)、BACTEC MGIT-960快速培养系统(培养法)、PCR-荧光探针法(PCR法)和Gene Xpert MTB/RIF系统(Xpert法)和进行检测并分析不同方法的阳性率及差异。结果Xpert法、培养法、PCR法和涂片法阳性率分别为48.19%(200/415)、41.20%(171/415)、40.24%(167/415)和28.19%(117/415),差异有统计学意义(χ^(2)=35.937,P<0.01)。培养法和涂片法在痰液中阳性率分别为48.05%(74/154)、41.56%(64/154),均显著高于BALF中阳性率37.16%(97/261)、20.31%(53/261),差异有统计学意义(χ^(2)_(培养)=4.739,χ^(2)_(涂片)=21.607,P<0.05);而Xpert法和PCR法在痰液和BALF中阳性率差异无统计学意义(χ^(2)_(Xpert)=0.025,χ^(2)_(PCR)=0.394,P>0.05)。4种不同检测方法在痰液中两两之间阳性率差异无统计学意义(P>0.05);而在BALF中,Xpert法阳性率显著高于其他3种方法,涂片法显著低于其他3种方法,差异有统计学意义(Xpert法相对于其他3种方法的χ^(2)值分别为6.145、4.124和44.193,P<0.05;涂片法的χ^(2)值分别为18.111、44.193、22.033,P<0.01),而培养法与PCR法阳性率之间差异无统计学意义(P>0.05)。与培养法检测结果相比,Xpert法与涂片法在痰液中检测结果均为高度一致(Kappa值分别为0.753、0.765,P<0.01),而在BALF中3种不同检测方法与痰液中Kappa值相比均有所降低,且均为中度一致(Kappa值分别为0.588、0.537和0.494,P<0.01)。结论4种检测方法在肺结核患者痰液中阳性检出率无明显差异,均能够满足临床需求,但在BALF中阳性检出率差异较大。Xpert法和PCR法能够较好地应用于痰液和BALF中结核分枝杆菌检测,且Xpert法阳性检出率最高。

Objective To compare the positive detection rate of mycobacterium tuberculosis(MTB)in sputum and bronchoalveolar lavage fluid(BALF)samples by four different methods,and to evaluate respective clinical value in the diagnosis of tuberculosis.Methods A total of 415 cases of BALF and sputum in tuberculosis patients visiting Hebei Chest Hospital from January to June 2018 were collected.The sandwich cup bacteria collection and smear method(Smear),BACTEC MGIT-960 rapid culture system(Culture),PCR-fluorescent probe method(PCR)and Gene Xpert MTB/RIF system(Xpert)were used for detection of MTB,and the positive rates and differences of different methods for detecting MTB were analyzed.Results The positive rate of Xpert,Culture,PCR and Smear was 48.19%(200/415),41.20%(171/415),40.24%(167/415)and 28.19%(117/415)respectiively,and the differences was statistically significant(χ^(2)=35.937,P<0.01).The positive rates of Culture and Smear in the sputum were 48.05%(74/154)and 41.56%(64/154)respectively,being significantly higher than that in BALF at 37.16%(97/261)and 20.31%(53/261),the difference was statistically significant(χ^(2)_(Culture)=4.739,χ^(2)_(Smear)=21.607,P<0.05);whereas Xpert and PCR showed no difference in positive rates between sputum and BALF(χ^(2)_(Xpert)=0.025,χ^(2)_(PCR)=0.394,P>0.05).The difference in pairwise positive rate between four different detection methods in the sputum weren’t statistically significant(P>0.05).The positive rate of Xpert in BALF was significantly higher than that of other three methods,the positive rate of Smear was significantly lower than that of other three methods,and the difference was statistically significant(χ^(2) value of Xpert was 6.145,4.124 and 44.193 when compared that of the remaining three methods,P<0.05,andχ^(2) values of Smear was 18.111,44.193,and 22.033 respectively,P<0.01),and the difference in the positive rate of Culture and PCR wasn’t statistically significant(P>0.05).Compared to the test results of Culture,the test results of Xpert and Smear highly matched in the sputum test(Kappa values was 0.753 and 0.765 respectively,P<0.01).Kappa value in BALF with three different detection methods were lower than those in the sputum and moderately matched(Kappa value was 0.588,0.537 and 0.494 respectively,P<0.01).Conclusion There is no significant difference in the positive detection rate of four detection methods in the sputum of patients with tuberculosis,these methods can meet clinical requirements,while the positive detection rate in BALF vary significantly.Xpert and PCR can be greatly applied to test mycobacterium tuberculosis in the sputum and BALF,and Xpert is the method with maximum positive detection rate.