多色巢式荧光定量PCR的半定量水平对结核病的诊断价值

The diagnostic value of semi-quantitative Xpert MTB/RIF level in tuberculosis

目的评估多色巢式荧光定量PCR(Xpert MTB/RIF)的半定量水平与MGIT 960液体培养的报阳率、报阳时间和利福平的耐药情况之间的关系。方法回顾性收集同时行痰液Xpert MTB/RIF及MGIT 960液体培养检测的患者共376例,根据Xpert MTB/RIF检测阈值将其分为4组进行比较。结果高含量组(98.1%)和中含量组(95.3%)的MGIT 960报阳率均较极低含量组(39.2%)和低含量组(66.1%)显著增高(P <0.01)。同时中等含量组(16.0 d)和高含量组(13.0 d)的报阳时间均较极低含量组(23.0 d)和低含量组(20.0 d)显著更短(P <0.01)。此外,以MGIT 960药敏试验结果为金标准,高含量组(96.2%)和中含量组(92.1%)耐药基因检测的准确度均较极低含量组(35.4%)和低含量组(63.6%)显著增高(P <0.01)。结论 Xpert MTB/RIF试验半定量结果为中等含量及以上时,液体培养的报阳率更高、报阳时间也更短,并且利福平的耐药基因检测的准确度也更高。

Objective To evaluate the relationship between semi-quantitative Xpert MTB/RIF level and the positive rate,reporting time and rifampicin resistance in MGIT 960 liquid culture. Methods The retrospective study enrolled 376 patients,the specimens of who were detected by Xpert MTB/RIF and MGIT 960 rapid liquid culture at the same time. The patients were separated in four groups for comparison according to semi-quantitative Xpert MTB/RIF level. Results The positive rate in MGIT 960 liquid culture of the very medium( 95. 3%) and high content group( 98. 1%) were both significantly higher than that in the very low( 66. 1%) and low content group( 39. 2%)( P < 0. 01). Meanwhile,the reporting time in MGIT 960 liquid culture of the medium( 16. 0 d) and high content group( 13. 0 d) were significantly shorter than that in the very low( 23. 0 d) and low content group( 20. 0 d)( P < 0. 01). With the drug sensitivity test of MGIT 960 liquid culture as the gold standard,the accuracy in the very low,low,medium and high content group were respectively 35. 4%( 28/79),63. 6%( 75/118),92. 1%( 117/127),96. 2%( 50/52). The accuracy of rifampicin detection in the medium( 92. 1%) and high content group( 96. 2%) were significantly higher than that in the very low( 35. 4%) and low content group( 63. 6%)( P <0. 01). Conclusion When the semi-quantitative results of Xpert MTB/RIF are at medium level and above,the positive rate of liquid culture is higher,the time of reporting positive is shorter,and the accuracy of rifampicin resistance gene detection is also higher.