Detection of Drug-Resistant Tuberculosis by Xpert MTB/RIF in Swaziland

Sánchez-Padilla, Elisabeth; Merker, Matthias; Beckert, Patrick; Jochims, Frauke; Dlamini, Themba; Kahn, Patricia; Bonnet, Maryline; Niemann, Stefan

doi:10.1056/nejmc1413930

Cited by 155 publications

(138 citation statements)

References 3 publications

Supporting

Mentioning

133

Contrasting

Unclassified

Order By: Relevance

“…Genetic screening for DST by currently available rapid commercial tests (Xpert MTB/RIF, GenoType MTBDRplus version 1.0 and 2.0, and INNO-LiPA Rif. TB) are limited to previously described mutations and cannot detect resistance-associated mutations encountered outside the mutation hot spots (51). The current version of the HRM assay does not include mutation detection outside the 81-bp RRDR region; however, the assay can be easily modified by including plasmid controls and amplifying specific gene regions to include these novel mutations for resistance screening.…”

Section: Discussionmentioning

confidence: 99%

Direct Detection of Rifampin and Isoniazid Resistance in Sputum Samples from Tuberculosis Patients by High-Resolution Melt Curve Analysis

et al. 2017

View full text Add to dashboard Cite

Drug-resistant tuberculosis (TB) is a major threat to TB control worldwide. Globally, only 40% of the 340,000 notified TB patients estimated to have multidrug-resistant-TB (MDR-TB) were detected in 2015. This study was carried out to evaluate the utility of high-resolution melt curve analysis (HRM) for the rapid and direct detection of MDR-TB in Mycobacterium tuberculosis in sputum samples. A reference plasmid library was first generated of the most frequently observed mutations in the resistance-determining regions of rpoB, katG, and an inhA promoter and used as positive controls in HRM. The assay was first validated in 25 MDR M. tuberculosis clinical isolates. The assay was evaluated on DNA isolated from 99 M. tuberculosis culture-positive sputum samples that included 84 smear-negative sputum samples, using DNA sequencing as gold standard. Mutants were discriminated from the wild type by comparing melting-curve patterns with those of control plasmids using HRM software. Rifampin (RIF) and isoniazid (INH) monoresistance were detected in 11 and 21 specimens, respectively, by HRM. Six samples were classified as MDR-TB by sequencing, one of which was missed by HRM. The HRM-RIF, INH-katG, and INHinhA assays had 89% (95% confidence interval [CI], 52, 100%), 85% (95% CI, 62, 97%), and 100% (95% CI, 74, 100%) sensitivity, respectively, in smear-negative samples, while all assays had 100% sensitivity in smear-positive samples. All assays had 100% specificity. Concordance of 97% to 100% ( value, 0.9 to 1) was noted between sequencing and HRM. Heteroresistance was observed in 5 of 99 samples by sequencing. In conclusion, the HRM assay was a cost-effective (Indian rupee [INR] 400/US$6), rapid, and closed-tube method for the direct detection of MDR-TB in sputum, especially for direct smear-negative cases.KEYWORDS DNA sequencing, high-resolution melt curve analysis, tuberculosis, molecular diagnostics, multidrug resistance, sputum T uberculosis (TB) is one of the world's deadliest transmittable diseases (1). In 2015, worldwide, 10.4 million people were estimated to be infected with TB, with 1.4 million people dying from the disease. Drug-resistant TB is a menace for TB control worldwide, and 60% of reported TB patients estimated to have multidrug-resistant TB (MDR-TB) were not detected in 2015 (1). India holds the dubious distinction of harboring 27% of the global TB burden, with 2.5% of its new TB cases and 16% of previously treated cases having MDR-TB (1). Conventional Mycobacterium tuberculosis culturebased systems for first-line and second-line drug susceptibility testing (DST) are timeconsuming, while commercial liquid culture-based DST reduces turnaround times but

show abstract

Section: Discussionmentioning

confidence: 99%

Direct Detection of Rifampin and Isoniazid Resistance in Sputum Samples from Tuberculosis Patients by High-Resolution Melt Curve Analysis

et al. 2017

View full text Add to dashboard Cite

show abstract

“…30 A recent study in Swaziland found that, due to the prevalence of specific mutations in the rifampicin (RMP) gene, the sensitivity of Xpert to detect RMP resistance is reduced. 31 In response to this, routine culture and DST have now been introduced. The last MDR-TB prevalence survey dates from 2009; the planned drug resistance survey will give more insight into the current situation.…”

Section: Public Health Action Deaths Among Tb Patients On Hiv Treatmementioning

confidence: 99%

High mortality in tuberculosis patients despite HIV interventions in Swaziland

Mchunu¹,

Griensven

Hinderaker

et al. 2016

public health action

View full text Add to dashboard Cite

“…One study showed that rpoB 445 was a very strong factor in predicting rifampicin resistance [24]. A previous study in Swaziland showed rpoB 445 mutation in MDR-TB patients (79.17%) [22]. The rpoB 445 mutation was also found during the outbreak of MDR-TB in Argentina in 1973 [23].…”

Section: Discussionmentioning

confidence: 99%

The Prediction Factors of Pre-XDR and XDR-TB among MDR-TB Patients in Northern Thailand

Jaksuwan¹,

Patumanond²,

Tharavichikul³

et al. 2018

JTR

View full text Add to dashboard Cite

Background: Molecular diagnosis based on the detection of mutations conferring genetic drug resistance is useful for early diagnosis and treatment of Pre-XDR and XDR-TB patients. However, the study of mutation as a marker to predict Pre-XDR and XDR-TB is rare. Methods: Thirty-four Mycobacterium tuberculosis (MTB) isolates from MDR, Pre-XDR and XDR-TB patients in the upper north of Thailand, who had been identified for drug susceptibility using the indirect agar proportion method from 2005-2012, were examined for genetic site mutations of katG, inhA, and ahpC for isoniazid (INH) drug resistance, rpoB for rifampicin (RIF) drug resistance, gyrA for ofloxacin (OFX), and rrs for kanamycin (KAN). Associations between resistant genes and Pre-XDR and XDR-TB in the MDR patients were performed using exact probability tests. Univariable logistic regression was used to quantify the strength of association between the gene mutation with Mycobacterium tuberculosis and the prevalence of Pre-XDR and XDR-TB in the MDR patients. Results: The mutations in the region of the rpoB gene at codon 445 (C445T) in the Pre-XDR or XDR-TB patients were significantly 20.6 times more prevalent among the MDR-TB patients. The inhA gene mutation at codon 114 (T114G) was also significantly 8.1 times more prevalent. Conclusion: The findings can be used to predict the odds of Pre-XDR and XDR-TB in MDR-TB patients, as a guide for prevention and treatments.

show abstract

Detection of Drug-Resistant Tuberculosis by Xpert MTB/RIF in Swaziland

Cited by 155 publications

References 3 publications

Direct Detection of Rifampin and Isoniazid Resistance in Sputum Samples from Tuberculosis Patients by High-Resolution Melt Curve Analysis

Direct Detection of Rifampin and Isoniazid Resistance in Sputum Samples from Tuberculosis Patients by High-Resolution Melt Curve Analysis

High mortality in tuberculosis patients despite HIV interventions in Swaziland

The Prediction Factors of Pre-XDR and XDR-TB among MDR-TB Patients in Northern Thailand

Contact Info

Product

Resources

About