Diagnosis of Multi-drug Resistant Tuberculosis Mutations Using Hain Line Probe Assay and GeneXpert: A Study Done in Zimbabwe

Racheal, S.; Dhlamini, Z.; Mutetwa, Reggie; Duri, Kerina; Stray‐Pedersen, Babill; Mátyus, Péter

doi:10.9734/bjmmr/2015/13979

Cited by 6 publications

(10 citation statements)

References 7 publications

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“…In this study our finding was that 90% of RIF isolates were MDR-TB consistent with previous studies that say the majority of MTB isolates worldwide have mutations within the 81bp core region of the rpoB gene [ 20 ]. The most frequently mutated codon in our study was S531L (25/92), followed by D516G/Y/del (8/92) and H526D, H526L (4/92) which was similar to those reported from other clinical isolates [ 25 , 31 ].…”

Section: Discussionsupporting

confidence: 91%

“…Rifampicin resistance has been found to be associated with a hotspot (codon 507-533) core region called rifampicin resistant determining region (RRDR) where several authors have described the presence of common as well as novel mutations for rpoB gene especially in the hotspot region as well as outside the hotspot region but within the rpoB gene [ 20 , 24 , 25 ]. This diversity has been shown to demonstrate implications in the vaccines and diagnostics for TB.…”

Section: Discussionmentioning

confidence: 99%

“…This lack of genotyping data prevents the identification of unexpected and unsuspected transmission pattern including transnational spread [ 19 ]. MDR-TB cases pose a huge challenge in controlling the infection, thus indicating the need for timely and accurate laboratory diagnosis for optimizing treatment and preventing its spread [ 20 ]. The patterns and frequency of mutations in the rifampicin resistance determining region of the rpoB gene in MTB clinical isolates vary significantly according to the geographical location and ( Figure 1 ) in addition, the available data regarding the pattern of rpoB gene mutations in MDR-TB patients in Zimbabwe limited [ 21 ].…”

Section: Introductionmentioning

confidence: 99%

“…This would require an established set of known mutations that are linked to resistance since not all mutations have been recorded as shown by isolates that lack mutations but still display resistance to antibiotics [ 16 , 19 , 23 ]. For example, the Hain's Genotype MTBDRplus kit has defined mutations and therefore, gene sequencing would be recommended to rule out any possible novel mutations [ 20 ]. Although certain mutations have been highly associated with drug resistance other mutations such as those recently discovered and still to be discovered could be utilized in sequence based testing to lower the discordance frequency and thus, increase the sensitivity [ 18 ].…”

Section: Introductionmentioning

confidence: 99%

“…With this in mind, significant geographical differences in the type of mutations as well as discordances have been found. This research was therefore also intended at generating more information that could be useful in enabling sequence based tests to be possibly targeted for each specific geographic region rather than using a single general test used worldwide [ 19 , 20 ]. The objectives of this research was to determine the drug resistance profiles in M. tuberculosis isolates that are phenotypically resistant but not detected by the GeneXpert and MTBDRplus kit and also to detect mutations in the rpoB and katG genes which are not detected by the Hain Genotype MTBDRplus kit and GeneXpert diagnosis.…”

Section: Introductionmentioning

confidence: 99%

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Mutations in rpoB and katG genes of multidrug resistant mycobacterium tuberculosis undetectable using genotyping diagnostic methods

Takawira¹,

Mandishora²,

Dhlamini³

et al. 2017

Pan Afr Med J

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IntroductionTuberculosis remains the leading causes of death worldwide with frequencies of mutations in rifampicin and isoniazid resistant Mycobacterium tuberculosis isolates varying according to geographical location. There is limited information in Zimbabwe on specific antibiotic resistance gene mutation patterns in MTB and hence, increased rate of discordant results and mortality due to inappropriate antibiotic prescriptions. The rpoB and katG genes molecular markers are used for detecting rifampicin and isoniazid resistance respectively. Some mutations within these gene sequences are associated with drug resistance as they directly alter gene function. The objectives of this research was to determine the drug resistance profiles in M. tuberculosis isolates that are phenotypically resistant but not detected by the GeneXpert and MTBDRplus kit and also to detect mutations in the rpoB and katG genes which are not detected by the Hain Genotype MTBDRplus kit and GeneXpert diagnosis.MethodsPCR was used for the amplification of the rpoB and katG genes from MTB isolates collected from human clinical samples between 2008 and 2015. The genes were sequenced and compared to the wild type MTB H37Rv rpoB (accession number L27989) and kat G genes (KP46920), respectively. Sequence analysis results were compared to genotyping results obtained from molecular assays and culture results of all isolates.ResultsThe most frequent mutation responsible for rifampicin resistance was (25/92) S531L that was detected by using all molecular assays. Some inconsistencies were observed between phenotypic and genotypic assay results for both katG and rpoB genes in 30 strains. For these, eight codons; G507S, T508A, L511V, del513-526, P520P, L524L, R528H, R529Q and S531F were novel mutations. In addition, the I572P/F, E562Q, P564S, and Q490Y mutations were identified as novel mutations outside the rifampicin resistance determining region. In katG gene, amino acid changes to threonine, asparagine and isoleucine exhibited high degrees of polymorphism such as V473N, D311N, and L427I. The R463L (20/92) amino acid substitution was most common but was not associated with isoniazid resistance.ConclusionThese finding indicate that molecular assay kit diagnosis that is based on the rpoB and katG genes should be improved to cater for the genetic variations associated with the geographic specificity of the target genes and be able to detect most prevalent mutations in different areas.

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Mutations in rpoB and katG genes of multidrug resistant mycobacterium tuberculosis undetectable using genotyping diagnostic methods

Takawira¹,

Mandishora²,

Dhlamini³

et al. 2017

Pan Afr Med J

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Mutations in rpoB and katG genes and the inhA operon in multidrug-resistant Mycobacterium tuberculosis isolates from Zambia

Solo

Nakajima

Kaile

et al. 2020

Journal of Global Antimicrobial Resistance

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Xpert My cobacterium tuberculosis/Rifampicin–Detected Rifampicin Resistance is a Suboptimal Surrogate for Multidrug-resistant Tuberculosis in Eastern Democratic Republic of the Congo: Diagnostic and Clinical Implications

Bisimwa

Nachega

Warren

et al. 2020

Clinical Infectious Diseases

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BACKGROUND Rifampicin (RIF) resistance is highly correlated with isoniazid (INH) resistance and used as proxy for multidrugresistant tuberculosis (MDR-TB). Using MTBDRplus as a comparator, we evaluated the predictive value of Xpert® MTB/RIF (Xpert)detected RIF resistance for MDR-TB in eastern Democratic Republic of the Congo (DRC). METHODS We conducted a cross-sectional study involving data from new or retreatment pulmonary adult TB cases evaluated between July 2013 and December 2016. Separate, paired sputa for smear microscopy and MTBDRplus were collected. Xpert testing was performed subject to the availability of Xpert cartridges on sample remnants after microscopy. RESULTS Among 353 patients, 193 (54.7%) were previously treated and 224 (63.5%) were MTBDRplus TB-positive. Of the 224, 43 (19.2%) were RIFmono-resistant, 11 (4.9%) were INHmono-resistant, 53 (23.7%) had MDR-TB, and 117 (52.2%) were RIF- and INH-susceptible. Overall, among the 96 samples detected by MTBDRplus as RIF-resistant, 53 (55.2%) had MDR-TB. Xpert testing was performed in 179 (50.7%) specimens, and amongst these, 163 (91.1%) were TB-positive and 73 (44.8%) RIF-resistant. Only 45/73 (61.6%) Xpertidentified RIF-resistant isolates had concomitant MTBDRplus-detected INH resistance. Xpert had a sensitivity of 100.0% (95% CI; 92.1-100.0) for detecting RIFresistance but a positive predictive value of only 61.6% (95% CI; 49.5-72.8) for MDR-TB. The most frequent mutations associated with RIF and INH resistance were S531L and S315T1, respectively. CONCLUSIONS In this high-risk MDR-TB study population, Xpert had low positive predictive value for the presence of MDR-TB. Comprehensive resistance testing for both INH and RIF should be performed in this setting.

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Diagnosis of Multi-drug Resistant Tuberculosis Mutations Using Hain Line Probe Assay and GeneXpert: A Study Done in Zimbabwe

Cited by 6 publications

References 7 publications

Mutations in rpoB and katG genes of multidrug resistant mycobacterium tuberculosis undetectable using genotyping diagnostic methods

Mutations in rpoB and katG genes of multidrug resistant mycobacterium tuberculosis undetectable using genotyping diagnostic methods

Mutations in rpoB and katG genes and the inhA operon in multidrug-resistant Mycobacterium tuberculosis isolates from Zambia

Xpert My cobacterium tuberculosis/Rifampicin–Detected Rifampicin Resistance is a Suboptimal Surrogate for Multidrug-resistant Tuberculosis in Eastern Democratic Republic of the Congo: Diagnostic and Clinical Implications

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