Rapid genotypic assays to identify drug-resistant Mycobacterium tuberculosis in South Africa

Evans, Joanna C.; Stead, Michael C.; Nicol, Mark P.; Segal, Heidi

doi:10.1093/jac/dkn433

Cited by 37 publications

(35 citation statements)

References 27 publications

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“…The S531L mutation in rpoB was most prevalent in the RIF r isolates, at a frequency (30/47, 63.8%) similar to that generally reported elsewhere (1,3,5,6,8,11,13,17 (5). Seven strains had both the wild-type pattern and mutant probe positivity (Table 2 and Table 3), possibly indicating the presence of a mixture of wild-type and mutated DNA sequences.…”

Section: Discussionsupporting

confidence: 80%

DNA Extracted from Stained Sputum Smears Can Be Used in the MTBDR plus Assay

et al. 2011

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We examined the feasibility of using DNA extracted from stained sputum smears for the detection of rifampin and isoniazid resistance with the commercial MTBDRplus assay from Hain Lifescience GmbH, Nehren, Germany. Overall sensitivity was initially low (70.0%) but increased to 96.7% when a multiplex PCR preamplification step was added. We then tested stored Mycobacterium tuberculosis-positive stained smears prepared from 297 patients' sputum samples. Species identification and drug susceptibility testing (DST) had been performed at the Institut Pasteur de Madagascar. Overall, the performance of the MTBDRplus assay applied to slide DNA was similar to that obtained in other studies with DNA extracted from clinical specimens. With the ready availability of stained smears in routine diagnostic laboratories and their easy transport and storage at room temperature, this approach should be useful for optimizing the treatment of multidrugresistant tuberculosis and for conducting resistance surveys aimed at identifying hot-spot regions and breaking chains of transmission.Multidrug-resistant tuberculosis (MDR-TB) poses a formidable worldwide challenge for control programs, because of complex diagnostic and treatment issues. Less than 5% of MDR-TB patients are currently being diagnosed, owing to a severe lack of laboratory capacity. Alarming increases in MDR-TB, the emergence of extensively drug resistant TB (XDR-TB), potential institutional transmission, and the rapid progression of HIV-coinfected MDR-TB and XDR-TB patients call for rapid screening methods (25). Novel technologies for rapid detection of anti-TB drug resistance have therefore become a priority in TB research and development, and molecular line-probe assays have already been developed for rapid detection of resistance to rifampin (RIF), isoniazid (INH), fluoroquinolones, and injectable drugs (9, 25).The MTBDRplus assay (Hain Lifescience GmbH, Nehren, Germany) has estimated sensitivities of 91.7% to 100% and 73% to 100% for the detection of RIF and INH resistance, respectively, in clinical strains (1-3, 6, 8, 10, 11, 13, 15, 17). However, because of the need for trained staff, specific equipment, and dedicated infrastructure, such tests are currently restricted to specialized laboratories. Even when these tests are available, detection of resistance in developing countries is often restricted by transport and storage of sputum samples from remote locations.It has been shown that Mycobacterium tuberculosis complex DNA present in Ziehl-Neelsen-or auramine-stained smears can be extracted and used in molecular tests (7,19,(21)(22)(23)(24). In this study, we show that the MTBDRplus assay can be applied to DNA extracted from microscopy-positive stained sputum smears from patients with relapse, treatment failure, and newly diagnosed TB. MATERIALS AND METHODS Stored stained slides.We selected 297 stored smear-positive stained slides prepared from TB patients' sputum samples between January 2003 and March 2010. Species identification and drug susceptibility testing (D...

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Section: Discussionsupporting

confidence: 80%

DNA Extracted from Stained Sputum Smears Can Be Used in the MTBDR plus Assay

et al. 2011

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“…Previous evaluations of the GenoType kits have documented their performance in detecting resistance to first-and second-line antituberculosis (anti-TB) drugs in different continents, like Africa, Asia, and Europe (2,3,4,5). From these studies, it became clear that there are geographic variations in the mutations that are associated with drug resistance in Mycobacterium tuberculosis (6).…”

Section: N June 2008 the World Health Organization (Who) Endorsedmentioning

confidence: 99%

Predictive Value of Molecular Drug Resistance Testing of Mycobacterium tuberculosis Isolates in Valle del Cauca, Colombia

et al. 2013

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Previous evaluations of the molecular GenoType tests have promoted their use to detect resistance to first-and second-line antituberculosis drugs in different geographical regions. However, there are known geographic variations in the mutations associated with drug resistance in Mycobacterium tuberculosis, and especially in South America, there is a paucity of information regarding the frequencies and types of mutations associated with resistance to first-and second-line antituberculosis drugs. We therefore evaluated the performance of the GenoType kits in this region by testing 228 M. tuberculosis isolates in Colombia, including 134 resistant and 94 pansusceptible strains. Overall, the sensitivity and specificity of the GenoType MTBDRplus test ranged from 92 to 96% and 97 to 100%, respectively; the agreement index was optimal (Cohen's kappa, >0.8). The sensitivity of the GenoType MTBDRsl test ranged from 84 to 100% and the specificity from 88 to 100%. The most common mutations were katG S315T1, rpoB S531L, embB M306V, gyrA D94G, and rrs A1401G. Our results reflect the utility of the GenoType tests in Colombia; however, as some discordance still exists between the conventional and molecular approaches in resistance testing, we adhere to the recommendation that the GenoType tests serve as early guides for therapy, followed by phenotypic drug susceptibility testing for all cases.

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“…Studies have assessed the performance of the GenoType® MTBDRPlus assay in medium to high-TB burden countries demonstrating a reported sensitivity and specificity for RIF and INH drug resistance of 88-100% with overall good concordance with phenotypic DST results [4,9,[14][15][16][17]. However, most of the reported studies were based on convenience samples of bacterial isolates and were conducted in settings with low drug resistance rates or confined to limited geographical areas [4,14,16].…”

Section: Introductionmentioning

confidence: 99%

“…However, most of the reported studies were based on convenience samples of bacterial isolates and were conducted in settings with low drug resistance rates or confined to limited geographical areas [4,14,16].…”

Section: Introductionmentioning

confidence: 99%

Performance of the GenoType® MTBDRPlus assay in routine settings: a multicenter study

Mironova

Pimkina

Kontsevaya

et al. 2011

Eur J Clin Microbiol Infect Dis

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Former Soviet Union countries including the Baltic States (Latvia, Lithuania, and Estonia) are hot spots for an emerging epidemic of drug resistant tuberculosis (TB). As a part of the development of a co-ordinated network of centers for diagnostic trials across Eastern Europe we conducted a retrospective multicenter analysis of the performance of the GenoType® MTBDRPlus assay for TB identification and susceptibility to isoniazid (INH) and rifampicin (RIF) in routine settings. A total of 1,045 primary samples, 1045 TB cultures derived from these specimens and 306 separate M. tuberculosis isolates tested in 2007-2010 at four participating sites (Tartu, Estonia; Riga, Latvia; Vilnius, Lithuania; and Samara, Russian Federation) were included in the analysis. The pooled sensitivity and specificity values for RIF and INH were 95.3% and 95.5%, 89.9 and 87.1%, respectively; there were no statistically significant variations in performance across sites. The proportion of multidrug resistant (MDR) strains in the collections ranged from 21.8% (in Estonia) to 55.9% (in Russia). In a routine non-trial context, the assay reliably detected both rifampicin and isoniazid resistance. The absence of statistically significant differences between sites suggested that the comparable performance obtained using these assays has helped demonstrate the formation of a successful diagnostic trial network.

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Rapid genotypic assays to identify drug-resistant Mycobacterium tuberculosis in South Africa

Cited by 37 publications

References 27 publications

DNA Extracted from Stained Sputum Smears Can Be Used in the MTBDR plus Assay

DNA Extracted from Stained Sputum Smears Can Be Used in the MTBDR plus Assay

Predictive Value of Molecular Drug Resistance Testing of Mycobacterium tuberculosis Isolates in Valle del Cauca, Colombia

Performance of the GenoType® MTBDRPlus assay in routine settings: a multicenter study

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