GeneXpert MTB/RIF assay in the diagnosis of urinary tuberculosis from urine specimens

Yu Pang,Liping Zhao,Yunxu Li,Jie Lu,Hairong Huang,Lingling Dong,Yuanyuan Shang,Qian Liang,Guanglu Jiang

doi:10.1038/s41598-017-06517-0

Abstract

Conventional bacteriological methods are not generally helpful in diagnosing urinary tuberculosis (UTB). GeneXpert is endorsed for the detection of pulmonary tuberculosis, whereas the data on its utility for urine specimens is limited. In this study, we aimed to evaluate its performance on urine specimens in a country with high TB incidence. A total of 163 suspected UTB patients were consecutively enrolled in the analysis, including 37 (22.7%) culture-positive and 44 (27.0%) clinically diagnosed UTB cases. Compared with conventional culture, the sensitivity of GeneXpert (94.6%) was significantly higher than that of smear microscopy (40.5%, P < 0.001). When setting clinical diagnosis as gold standard, 51 out of 81 clinically diagnosed UTB cases were detected by GeneXpert, demonstrating a sensitivity of 63.0%, which was significantly higher than that of smear microscopy (18.5%, P < 0.001) and culture (45.7%, P = 0.027), respectively. In addition, the proportion of UTB cases in the migrant population was significantly higher than that in the resident population (P = 0.019). To conclude, our data demonstrate that GeneXpert outperforms AFB smear and culture for the detection of MTB in urine samples, which provides an alternative for the diagnosis of UTB. The migrant population and previously diagnosed TB cases are high risk factors for developing UTB cases.

Highlights

Tuberculosis (TB), caused by Mycobacterium tuberculosis complex (MTBC), remains a major global public health concern and is the first leading cause of death from infectious diseases worldwide[1, 2]
When compared with L-J culture, the sensitivity of acid-fast bacilli (AFB) microscopy and GeneXpert were 40.5% (15/37, 95% confidence interval [CI]: 24.7–56.4%) and 94.6% (35/37, 95% CI: 87.3–100.0%), respectively
We have evaluated the fully automated GeneXpert assay for diagnosis of Urinary TB (UTB) from urine specimens, and compared it with AFB smears as well as the L-J culture

Summary

Introduction

Tuberculosis (TB), caused by Mycobacterium tuberculosis complex (MTBC), remains a major global public health concern and is the first leading cause of death from infectious diseases worldwide[1, 2]. A series of studies from industrialized countries demonstrated that the contribution of EPTB to the total TB burden has significantly increased in recent years[5, 6]. Despite the increased trend seen in several regions, EPTB is rarely given high priority in the public health sector, which is mainly because EPTB is not significantly associated with the community transmission of the disease[5]. Patients fulfill criterion A or B: A) Clinical suspected cases plus one or more of the following: positive smear microscopy examination; or positive mycobacterial culture examination. We have evaluated the performance of the GeneXpert on urine specimens for diagnosis of urinary TB in a country with high TB incidence

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