利福平耐药实时荧光定量核酸扩增技术在儿童结核病快速检测中的应用

Application of Gene Xpert Mycobacterium tuberculosis DNA and resistance to rifampicin assay in the rapid detection of tuberculosis in children

目的评价利福平耐药实时荧光定量核酸扩增检测技术（XpertMTB／RIF）在儿童结核病中的应用价值。方法收集2014年4月至2015年3月复旦大学附属公共卫生临床中心结核科住院109例临床疑似结核病患儿标本，其中疑似肺结核患儿65例（标本来源胃液46例、痰液19例），疑似肺外结核44例（标本来源穿刺液10例、脓液4例、脑脊液14例、浆膜腔积液11例、骨髓1例、粪便3例、尿液1例），分别进行荧光涂片显微镜检、液体快速生长培养、XpertMTB／RIF检测，同时所有患儿均抽取全血行T细胞斑点试验检测，分析XpertMTB／RIF方法对儿童结核病标本中结核分枝杆菌及其利福平耐药性检测的敏感度和特异度。结果XpertMTB／RIF在109例疑似儿童结核病临床标本中敏感度和特异度分别为28．6％、87．5％，65例疑似肺结核患儿敏感度为胃液33．3％、痰液57．1％，特异度均达100．0％；44例疑似肺外结核患儿脓液和穿刺液中的敏感度较高，接近100．0％，脑脊液和浆膜腔积液中检出率极低。涂阳培阳标本中敏感度均达100．0％，涂阴培阳中仅30．8％-50．0％；利福平耐药检测中敏感度和特异度均达100．0％。XpertMTB／RIF的敏感度（28．6％）优于荧光涂片（20．8％），差异无统计学意义（x^2=0，P〉0．05）；与BACTECMGIT960液体培养敏感度（27．3％）相比差异无统计学意义（x^2=2．50，P〉0．05）；远低于T细胞斑点试验（59．7％），差异有统计学意义（x^2=13．92，P〈0．05）。结论XpertMTB／RIF检测方法在儿童结核病中并不具有明显优势，尤其是在浆膜腔积液和脑脊液中，但其快速、可检测利福平耐药的优点使其为临床结核病患儿的诊疗提供帮助。

Objective To detect Mycobacterium tuberculosis （MTB） and rifampin resistance of the clinical specimens in children by Xpert MTB DNA and resistance to rifampicin （MTB/RIF） detection system, and evaluate the application value of this method in children with tuberculosis. Method Data of 109 children cases of clinically suspected tuberculosis were collected （ including 46 gastric lavage aspirate, 19 sputum, 10 fine needle aspiration biopsy,4 pus, 14 cerebrospinal fluid, 11 Serous membrance fluid, 1 marrow,3 stool, 1 urine specimens）between April 2014 and March 2015. All specimens were detected by smear fluorescence staining microscopy, MGIT 960 BACTEC liquid culture, Xpert MTB/RIF assay and T- SPOT. TB test respectively. The sensitivity and specificity of Xpert MTB/RIF assay were analyzed in those clinical specimens. Result The sensitivity and specificity of the Xpert MTB/RIF assay for MTB detection in childhood tuberculosis clinical specimen were 28.6% and 87.5%. The sensitivity of 65 pulmonary tuberculosis（46 gastric lavage aspirate,19 sputum） which included gastric lavage aspirates and sputum was 33.3% and 57. 1%, the specificity of the two was 100. 0%. In 44 extrapulmonary tuberculosis, the sensitivity of the pus and the puncture fluid was higher and approached 100.0%. The detection rate of the cerebrospinal fluid and serous cavity effusion was very low. The sensitivity was 100. 0% in smear-positive and culture-positive samples and only 30. 8% to 50. 0% in smear-negative and culture-positive samples. The sensitivity and specificity of Xpert MTB/RIF assay to detect rifampin resistance were 100. 0%. In clinical samples, the sensitivity of Xpert MTB/RIF assay was higher than that of smear fluorescence staining microscopy, but the difference was not statistically significant （ X^2 = 0, P 〉 0. 05 ）. The result was equivalent to that of MGIT 960 BACTEC liquid culture （28.6% vs. 27.3%, X^2 = 2. 50, P 〉 0. 05 ）, and far below that of T-SPOT. TB（28.6% vs 59.7%, x^2 = 13.92, P 〈 0. 05）. Conclusion Xpert MTB/RIF assay did not show obvious advantage in childhood tuberculosis, especially in serous cavity effusion and cerebrospinal fluid, but the advantages of detecting tuberculosis rapidly and resistance to rifampin can provide help for the clinical diagnosis and treatment in childrenhood tuberculosis.