Discordance of Rifampin Resistance Result by GeneXpert MTB/RIF, Phenotypic and Molecular Methods in A TB Patient: Case Report

結核分生（GeneXpert MTB/RIF）檢測出Rifampin抗藥性結果與傳統結核藥敏報告不符合之探討：案例報告

吳哲慰(Che-Wei Wu) ； 余秀珊(Hsiu-Shan Yu) ； 白雅文(Ya-Wen Bai) ； 莊寒玉(Han-Yu Chung) ； 陳志豪(Chih-Hao Chen)

《內科學誌》 32卷5期 (2021/10) Pp. 356-362

https://doi.org/10.6314/JIMT.202110_32(5).07

摘要

GeneXpert MTB/RIF can quickly detect Mycobacterium tuberculosis and whether it is a drug-resistant strain to provide doctors with accurate medication treatment and prevention. This case presented to the doctor due to urogenital discomfort. The chest radiography(CXR) during hospitalization revealed an abnormality. The sputum acid fast staining in the laboratory was positive, and the sputum and urine samples were sent for GeneXpert MTB/RIF. It is positive for MTB and resistant to Rifampin (RIF). But it is found that Rifampin (RIF) is sensitive through gold standard LJ proportion drug susceptibility (LJ-DST). After further genetic analysis, it was found that the gene rpoB had silent mutation P520P (silent mutation P520P), so the susceptibility of rifampin was judged to be sensitive. This similar genomic mutation cases are really rare and there were only 8 cases reported in Taiwan.

關鍵字

Mycobacterium tuberculosis ； GeneXpert MTB/RIF ； Silent mutation P520P

並列摘要

GeneXpert MTB/RIF能快速檢測結核桿菌及其是否為抗藥性菌株，以提供醫師正確之用藥治療及防治隔離是具有其相當重要性。此個案因泌尿生殖系統不適而就診，於住院時的胸部光檢查（CXR）發現異常，經由實驗室痰液抗酸性染色為陽性，而送驗痰液及尿液檢體做GeneXpert MTB/RIF皆呈現MTB陽性及Rifampin（RIF）抗藥，但經由傳統瓊指藥敏試驗卻發現Rifampin（RIF）是不具抗藥性而是具有敏感性的。再經由進一步基因分析下發現其基因rpoB發生Silent mutation P520P（沉默的突變P520P），故仍以Rifampin表現敏感性為最終判定。這種相似的基因組突變病例確實很罕見，目前台灣約有8例。