Consequences of rpoB mutations missed by the GenoType MTBDRplus assay in a programmatic setting in South Africa
African Journal of Laboratory Medicine
| Field | Value | |
| Title | Consequences of rpoB mutations missed by the GenoType MTBDRplus assay in a programmatic setting in South Africa | |
| Creator | Mvelase, Nomonde R. Cele, Lindiwe P. Singh, Ravesh Naidoo, Yeshnee Giandhari, Jennifer Wilkinson, Eduan de Oliveira, Tulio Swe Swe-Han, Khine Mlisana, Koleka P. | |
| Description | Background: Rifampicin resistance missed by commercial rapid molecular assays but detected by phenotypic assays may lead to discordant susceptibility results and affect patient management.Objective: This study was conducted to evaluate the causes of rifampicin resistance missed by the GenoType MTBDRplus and its impact on the programmatic management of tuberculosis in KwaZulu-Natal, South Africa.Methods: We analysed routine tuberculosis programme data from January 2014 to December 2014 on isolates showing rifampicin susceptibility on the GenoType MTBDRplus assay but resistance on the phenotypic agar proportion method. Whole-genome sequencing was performed on a subset of these isolates.Results: Out of 505 patients with isoniazid mono-resistant tuberculosis on the MTBDRplus, 145 (28.7%) isolates showed both isoniazid and rifampicin resistance on the phenotypic assay. The mean time from MTBDRplus results to initiation of drug-resistant tuberculosis therapy was 93.7 days. 65.7% of the patients had received previous tuberculosis treatment. The most common mutations detected in the 36 sequenced isolates were I491F (16; 44.4%) and L452P (12; 33.3%). Among the 36 isolates, resistance to other anti-tuberculosis drugs was 69.4% for pyrazinamide, 83.3% for ethambutol, 69.4% for streptomycin, and 50% for ethionamide.Conclusion: Missed rifampicin resistance was mostly due to the I491F mutation located outside the MTBDRplus detection area and the L452P mutation, which was not included in the initial version 2 of the MTBDRplus. This led to substantial delays in the initiation of appropriate therapy. The previous tuberculosis treatment history and the high level of resistance to other anti-tuberculosis drugs suggest an accumulation of resistance. | |
| Publisher | AOSIS | |
| Date | 2023-02-06 | |
| Identifier | 10.4102/ajlm.v12i1.1975 | |
| Source | African Journal of Laboratory Medicine; Vol 12, No 1 (2023); 8 pages 2225-2010 2225-2002 | |
| Language | eng | |
| Relation |
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https://ajlmonline.org/index.php/ajlm/article/view/1975/2562
https://ajlmonline.org/index.php/ajlm/article/view/1975/2563
https://ajlmonline.org/index.php/ajlm/article/view/1975/2564
https://ajlmonline.org/index.php/ajlm/article/view/1975/2565
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