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Successful Treatment of a Multidrug-Resistant Tuberculosis Patient with a Negative Xpert MTB/RIF Test for Rifampicin-Resistant Tuberculosis in Guizhou Province of China: A Case Report

Authors Zhao ZL, Chen L, Zhang H

Received 8 January 2020

Accepted for publication 26 April 2020

Published 8 May 2020 Volume 2020:13 Pages 1351—1355


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 2

Editor who approved publication: Dr Eric Nulens

Zhao-Liang Zhao,1 Ling Chen,1 Hong Zhang1,2

1Tuberculosis Division of Respiratory and Critical Care Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, People’s Republic of China; 2Z-BioMed, Inc., Rockville, MD 20855, USA

Correspondence: Ling Chen; Hong Zhang Tel +86-851-28609237
Fax +86-851-28608239

Abstract: The Xpert MTB/RIF (Xpert) assay recommended by the World Health Organization (WHO) can be used to simultaneously detect Mycobacterium tuberculosis complex (MTBC) and rifampicin (RIF) resistance associated mutations. However, if Xpert testing results are negative for RIF resistance because mutations outside the RIF resistance-determining region (RRDR) are not detectable by the assay, patients with RIF-resistant/multidrug-resistant tuberculosis (RR/MDR-TB) will be treated inappropriately for several weeks prior to obtaining the drug susceptibility testing (DST) results. Here, we report a rare case of TB in Guizhou Province of China that was identified as RIF-susceptible by the Xpert MTB/RIF assay, but later was confirmed as MDR-TB by DST, and its successful treatment with effective second-line anti-TB drugs. We detected a rare rpoB mutation (Ile572Phe) in clinical samples of this patient, highlighting the importance of using other methods such as PCR and sequencing to complement the Xpert MTB/RIF assay for the routine diagnosis of RR/MDR-TB because of the limited scope of the assay. These complementary methods allow for the detection of rare rpoB mutations outside the RRDR and can be beneficial when used in geographical locations where such rpoB mutations are frequently reported. However, these methods may not be feasible for resource-limited settings.

Keywords: commercial tests, MTB/RIF Xpert assays, Ile572Phe, Ile491Phe, rifampicin/multidrug-resistant tuberculosis

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