Performance of the Xpert MTB/RIF assay for the diagnosis of pulmonary tuberculosis and rifampin resistance in a low-incidence, high-resource setting
نویسندگان
چکیده
Performance of the Xpert MTB/RIF assay, designed to simultaneously detect Mycobacterium tuberculosis complex (MTBC) and rifampin (RIF) resistance, has been well documented in low-resource settings with high TB-incidence. However, few studies have assessed its accuracy in low TB incidence settings. We evaluated the performance of Xpert MTB/RIF using clinical sputum specimens routinely collected from suspect pulmonary TB patients over a 4-year time period in San Diego County, California. Xpert MTB/RIF results were compared to acid-fast bacilli (AFB) smear microscopy, mycobacterial culture, and phenotypic drug susceptibility testing (DST). Of 751 sputum specimens, 134 (17.8%) were MTBC culture-positive and 2 (1.5%) were multidrug-resistant (MDR). For the detection of MTBC, Xpert MTB/RIF sensitivity was 89.6% (97.7% and 74.5% in smear-positive and -negative sputa, respectively) and specificity was 97.2%; while AFB smear sensitivity and specificity were 64.9% and 77.8%, respectively. Xpert MTB/RIF detected 35 of 47 smear-negative culture-positive specimens, and excluded 124 of 137 smear-positive culture-negative specimens. Xpert MTB/RIF also correctly excluded 99.2% (121/122) of nontuberculous mycobacteria (NTM) specimens, including all 33 NTM false-positives by smear microscopy. For the detection of RIF resistance, Xpert MTB/RIF sensitivity and specificity were 100% and 98.3%, respectively. Our findings demonstrate that Xpert MTB/RIF is able to accurately detect MTBC and RIF resistance in routinely collected respiratory specimens in a low TB-incidence setting, with comparable performance to that achieved in high-incidence settings; and suggest that under these conditions the assay has particular utility in detecting smear-negative TB cases, excluding smear-positive patients without MTBC disease, and differentiating MTBC from NTM.
منابع مشابه
Performance evaluation of the Xpert MTB/RIF assay according to its clinical application
BACKGROUND The Xpert MTB/RIF assay (Xpert assay; Cepheid, Sunnyvale, CA) is becoming the test of choice for the rapid diagnosis of tuberculosis and rifampin (RIF) resistance. The aim of this study was to evaluate the performance of the Xpert assay with respect to its clinical application at a tertiary care hospital in Korea, a country with an intermediate tuberculosis burden and high-resource. ...
متن کاملEvaluation of Xpert MTB/RIF in detection of pulmonary and extrapulmonary tuberculosis cases in China
Background: To evaluate the performance of Xpert MTB/RIF assay for direct detection of Mycobacterium tuberculosis (Mtb) and rifampin resistance in pulmonary and extrapulmonary tuberculosis (TB) patients in China. Material/Methods: We prospectively enrolled 506 TB patients to evaluate sensitivity and specificity of Xpert MTB/ RIF by comparing with Mtb culture, fluorescent staining smear microsco...
متن کاملAn evaluation of false-positive rifampicin resistance on the Xpert MTB/RIF
BACKGROUND Mycobacterium tuberculosis (MTB) is one of the most significant causes of mortality and morbidity. Early diagnose is important especially in multiple drug resistant tuberculosis to avoid transmission. Traditional techniques requires at least one to three weeks for diagnosis of tuberculosis. Diagnostic delays with multiple drug resistant tuberculosis are associated with worse clinical...
متن کاملRapid diagnosis of extra pulmonary tuberculosis by automated Xpert MTB/RIF assay
Introduction Although extra pulmonary tuberculosis accounts for only 10-15% of tuberculosis in India, they have high morbidity and mortality because of lack of good diagnostic methods. One of the recent molecular methods namely the Xpert MTB/RIF is a fully automated real time PCR system that detects M. tuberculosis (Mtb) complex and rifampicin resistance directly from clinical samples. This ass...
متن کاملRapid and effective diagnosis of tuberculosis and rifampicin resistance with Xpert MTB/RIF assay: a meta-analysis.
OBJECTIVES Xpert MTB/RIF (Cepheid) assay has been introduced for the diagnosis of tuberculosis (TB) and RIF-resistance. The meta-analysis was used to establish the overall accuracy of Xpert MTB/RIF assay for diagnosing TB and RIF-resistance. METHODS Based on comprehensive searches of the Pubmed and Embase, we identified outcome data from all articles estimating diagnostic accuracy with Xpert ...
متن کامل