Evaluation of the use of GeneXpert MTB/RIF in a zone with high burden of tuberculosis in Thailand

Abstract

GeneXpert MTB/RIF is a reliable molecular diagnostic tool capable of detecting Mycobacterium tuberculosis (MTB) and identifying genetic determinants of rifampicin (RIF) resistance. This study aimed to assess physicians’ diagnostic decision-making processes for TB based on GeneXpert MTB/RIF results and how this affected the initiation of multidrug resistance (MDR) treatment. This study employed a mixed method: data were collected retrospectively from the medical records of TB patients and in-depth interviews were conducted with healthcare workers in areas with a high TB burden in Thailand. A total of 2,030 complete TB records from 2 patient groups were reviewed, including 1443 suspected cases with negative smear results and 587 with high risk of MDR-TB. GeneXpert MTB/RIF was routinely used to assist the physicians in their decision-making for the diagnosis of pulmonary tuberculosis (PTB) and the initiation of MDR-TB treatment. The physicians used it as a “rule-in test” for all patients with negative chest X-rays (CXR) and smear results, to ensure timely treatment. Approximately one-fourth of the patients with negative CXR/smear and GeneXpert MTB/RIF results were diagnosed with PTB by the physicians, who based their decisions on other evidence, such as clinical symptoms, and did not use GeneXpert MTB/RIF as a “rule-out test.” GeneXpert MTB/RIF proved effective in early detection within a day, thereby radically shortening the time required to initiate second-line drug treatment. Despite its high sensitivity for detecting PTB and MDR-TB, GeneXpert MTB/RIF had contradictory results (false positive and/or false negative) for 21.8% of cases among patients with negative smear results and 41.1% of cases among patients with high risk of MDR-TB. Therefore, physicians still used the results of other conventional tests in their decision-making process. It is recommended that GeneXpert MTB/RIF should be established at all points of care and be used as the initial test for PTB and MDR-TB diagnosis.

The Next Frontier in Tuberculosis Investigation: Automated Whole Genome Sequencing for Mycobacterium tuberculosis Analysis

“…However, outbreaks caused by MDR strains with novel antimicrobial resistance (AMR) profiles may not be picked up by these assays, which focus on a limited number of targets. This underscores the importance of employing assays with a genome-wide approach that cover a broader range of resistance determinants [4]. Although molecular targeted assays have shown great value in TB AMR characterization [2], these methods are still dependent on known genotypic and mutation profiles [1].…”

“…Widespread adoption and implementation of this methodology remains challenging due to a lack of necessary infrastructure, the high cost of entry and the requirement for technical expertise to process the samples and analyze the generated sequencing data [4]. Integrating next generation (NGS) technologies with automation will alleviate these challenges and has been proven successful for application in the food safety and infectious diseases space [6][7][8][9].…”

“…Genomic DNA obtained from the culture collections (ATCC or BEI Resources) 3. DNA was extracted by Nevada State Public Health Laboratory (NSPHL) using Promega Maxwell RSC Cultured Cell Kit 4. DNA was extracted by San Francisco Public Health Laboratory (SFPHL) using Roche MagNA Pure 24 Total NA Isolation Kit 5 DNA was extracted by San Francisco Public Health Laboratory (SFPHL) using QIAGEN EZ1&2 Virus Mini Kit.…”

Access the Diagnostic Accuracy of GeneXpert to Detect <em>Mycobacterium tuberculosis</em> and Rifampicin-Resistance Tuberculosis among Presumptive Tuberculosis and Presumptive Drug Resistant Tuberculosis Patients

“…The fact that it allows diagnosis of TB simultaneously as pinpointing resistance to rifampicin treatment is vital in minimizing the transmission of drug-resistant TB in TB-endemic countries. The test function is based on a nucleicacid amplification assay that detects M. tuberculosis and rifampicin resistance patterns from the sputum and other body fluids [6]. Therefore, this study aimed to appraise the wide range of molecular diagnostics for drug-resistant tuberculosis (DR-TB) endorsed by the World Health Organisation and assess Xpert's utility for the rapid molecular diagnosis of Tuberculosis in a highburden setting, southern region in India.…”

Assess the Diagnostic Accuracy of GeneXpert to Detect Mycobacterium tuberculosis and Rifampicin-Resistant Tuberculosis among Presumptive Tuberculosis and Presumptive Drug Resistant Tuberculosis Patients

“…The fact that it allows diagnosis of TB simultaneously as pinpointing resistance to rifampicin treatment is vital in minimizing the transmission of drug-resistant TB in TB-endemic countries. The test function is based on a nucleic-acid amplification assay that detects M. tuberculosis and rifampicin resistance patterns from the sputum and other body fluids [9]. Therefore, this study aimed to assess the wide range of molecular diagnostics for drug-resistant tuberculosis (DR-TB) endorsed by the World Health Organization and assess GeneXpert's utility for the rapid molecular diagnosis of tuberculosis in a high-burden setting-the southern region of India.…”