scholarly journals Evaluation of rifampicin resistance and 81-bp rifampicin resistant determinant region of rpoB gene mutations of Mycobacterium tuberculosis detected with XpertMTB/Rif in Cross River State, Nigeria

2016 ◽  
Vol 5 ◽  
pp. S145-S146 ◽  
Author(s):  
Ernest A. Ochang ◽  
Ubong A. Udoh ◽  
Ubleni E. Emanghe ◽  
Gerald O. Tiku ◽  
Jonah B. Offor ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Gene Mutations ◽  
Rpob Gene ◽  
Rifampicin Resistance ◽  
Cross River ◽  
Cross River State

Emergence of Heteroresistance Mycobacterium Tuberculosis in Saudi Arabia

2020 ◽  
Vol 20 (4) ◽  
pp. 491-494 ◽  
Author(s):  
Eltayib H. Ahmed Abakur ◽  
Tarig M.S. Alnour ◽  
Faisel Abuduhier ◽  
Fahad M.A. Albalawi ◽  
Khalid A.S. Alfifi
Keyword(s):  
Saudi Arabia ◽  
Mycobacterium Tuberculosis ◽  
Clinical Specimen ◽  
Rpob Gene ◽  
Rifampicin Resistance ◽  
Resistant Bacteria ◽  
Kingdom Of Saudi Arabia ◽  
Preliminary Stage ◽  
The North ◽  
Genotype Mtbdrplus

Purpose: Heteroresistant Mycobacterium tuberculosis (MTB) is defined as a group of drug-susceptible and resistant bacteria in a single clinical specimen from tuberculosis (TB) patients. Heteroresistance of MTB is considered a preliminary stage to full resistance. The present study aimed to determine the heteroresistance in Mycobacterium tuberculosis in Tabuk province, in the north of the Kingdom of Saudi Arabia. Method: GenoType MTBDRplus assay was used to determine mutations associated with isoniazid and rifampicin resistance. Results: A total number of 46 confirmed M. tuberculosis positive sputum samples were scanned for heteroresistance. The present study revealed 3 (6.5%) heteroresistant mutations to either rpoB gene alone, 2 (4.4%) to rpoB and 1 (2.2%) to inhA genes. Conclusion: The detection of heteroresistant mutations could guide the initiation of an appropriate regimen of treatment.

scholarly journals Resistance profiles and rpoB gene mutations of Mycobacterium tuberculosis isolates in Taiwan

2013 ◽  
Vol 46 (4) ◽  
pp. 266-270 ◽  
Author(s):  
Yun-Ho Lin ◽  
Chun-Hsi Tai ◽  
Chia-Ru Li ◽  
Chin-Fu Lin ◽  
Zhi-Yuan Shi
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Gene Mutations ◽  
Rpob Gene

scholarly journals Does Xpert MTB/RIF Assay Give Rifampicin Resistance Results Without Identified Mutation? Review of Cases from Addis Ababa, Ethiopia.

2019 ◽  
Author(s):  
Ayinalem Alemu ◽  
Mengistu Tadesse ◽  
Getachew Seid ◽  
Helina Mollalign ◽  
Kirubel Eshetu ◽  
...  
Keyword(s):  
Molecular Beacon ◽  
Addis Ababa ◽  
Gene Mutations ◽  
Rpob Gene ◽  
Rifampicin Resistance ◽  
Reference Laboratory ◽  
Probe Type ◽  
Dna Amount ◽  
National Tuberculosis ◽  
E Region

Abstract Background: Xpert MTB/RIF Assay is currently used in Ethiopia for the rapid diagnosis of Mycobacterium tuberculosis (MTB) and mutations that confer Rifampicin resistance. Rifampicin resistance is determined based on any mutation in the 81 bp of rpoB gene using five overlapping probes represented as Probe A (codons 507–511), Probe B (codons 512–518), Probe C (codons 518–523), Probe D (codons 523–529) and Probe E (codons 529–533). In this review, we assessed the frequency of missed probe types for Rifampicin Resistance results. Methods: Data were reviewed from specimens received and tested using Xpert® MTB/RIF Assay at Ethiopian National Tuberculosis Reference Laboratory, in Addis Ababa from 15 July 2016 to 31 December 2018 retrospectively. All archived data were reviewed carefully to describe missed probe types and quantity of DNA in the sample. Results: A total of 100 specimens were reported as MTB Detected Rifampicin Resistance Detected by Xpert MTB/RIF assay. More than half (55%) of these results were reported from male patients. The median age was 28.0 years (5 months to 88 years). Majorities (62%) of the cases were detected from sputum. Among the total of 38 extra pulmonary samples, lymph node aspirates were accounted 50% (19/38). The most common mutations (81.0%) were found in Probe E region followed by Probe D (10.0%), and Probe B (3.0%). Mutations in Probe A and Probe C regions were not observed. However six (6.0%) Rifampicin resistance cases were found without any missed probe type. The delta Ct max is ≥4.3. No specimen yielded Rifampicin resistance associated with more than one probe failure or mutation combinations. Conclusion: Mutations associated with Probe E (codons 529–533) region were identified as the commonest rpoB gene mutations. The Rifampicin resistance results found without any identified missing probe needs a further study. Lower DNA amount was observed in extrapulmonary specimens compared with sputum. Keywords: Rifampicin-resistance, Molecular Beacon, DNA probes, Xpert MTB/RIF Assay

scholarly journals Does Xpert MTB/RIF Assay Give Rifampicin Resistance Results Without Identified Mutation? Review of Cases from Addis Ababa, Ethiopia.

2020 ◽  
Author(s):  
Ayinalem Alemu ◽  
Mengistu Tadesse ◽  
Getachew Seid ◽  
Helina Mollalign ◽  
Kirubel Eshetu ◽  
...  
Keyword(s):  
Molecular Beacon ◽  
Addis Ababa ◽  
Gene Mutations ◽  
Rpob Gene ◽  
Rifampicin Resistance ◽  
Reference Laboratory ◽  
Probe Type ◽  
Dna Amount ◽  
National Tuberculosis ◽  
E Region

Abstract Background: Xpert® MTB/RIF assay is currently used in Ethiopia for the rapid diagnosis of Mycobacterium tuberculosis (MTB) and mutations that confer Rifampicin resistance. Rifampicin resistance is determined based on any mutation in the 81 bp of rpoB gene using five overlapping probes represented as Probe A (codons 507–511), Probe B (codons 512–518), Probe C (codons 518–523), Probe D (codons 523–529) and Probe E (codons 529–533). In this review, we assessed the frequency of missed probe types for Rifampicin Resistance results. Methods: Data were reviewed from specimens received and tested using Xpert® MTB/RIF assay at Ethiopian National Tuberculosis Reference Laboratory, in Addis Ababa from 15 July 2016 to 31 December 2018 retrospectively. All archived data were reviewed carefully to describe missed probe types and the quantity of DNA in the sample. Results: A total of 100 specimens were reported as MTB Detected Rifampicin Resistance Detected by Xpert® MTB/RIF assay. More than half (55%) of these results were reported from male patients. The median age was 28.0 years (5 months to 88 years). Majorities (62%) of the cases were detected from sputum. Among the total of 38 extrapulmonary samples, lymph node aspirates were accounted for 50% (19/38). The most common mutations (81.0%) were found in the Probe E region followed by Probe D (10.0%), and Probe B (3.0%). Mutations in Probe A and Probe C regions were not observed. However, six (6.0%) Rifampicin resistance cases were found without any missed probe type. The delta Ct max is ≥4.3. No specimen yielded Rifampicin resistance associated with more than one probe failure or mutation combinations. Conclusion: Mutations associated with Probe E (codons 529–533) region were identified as the commonest rpoB gene mutations. The Rifampicin resistance results found without any identified missing probe needs further study. The lower DNA amount was observed in extrapulmonary specimens compared with sputum. Keywords: Rifampicin-resistance, Molecular Beacon, DNA probes, Xpert® MTB/RIF Assay

scholarly journals Automatic Identification of Individual rpoB Gene Mutations Responsible for Rifampin Resistance in Mycobacterium tuberculosis by Use of Melting Temperature Signatures Generated by the Xpert MTB/RIF Ultra Assay

2019 ◽  
Vol 58 (1) ◽  
Author(s):  
Yuan Cao ◽  
Heta Parmar ◽  
Ann Marie Simmons ◽  
Devika Kale ◽  
Kristy Tong ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Melting Temperature ◽  
Gene Mutations ◽  
Test Sample ◽  
Rpob Gene ◽  
Automatic Identification ◽  
Content Type ◽  
Automated Algorithm ◽  
Wide Range ◽  
Rifampin Resistance

ABSTRACT Molecular surveillance of rifampin-resistant Mycobacterium tuberculosis can help to monitor the transmission of the disease. The Xpert MTB/RIF Ultra assay detects mutations in the rifampin resistance-determining region (RRDR) of the rpoB gene by the use of melting temperature (Tm) information from 4 rpoB probes which can fall in one of the 9 different assay-specified Tm windows. The large amount of Tm data generated by the assay offers the possibility of an RRDR genotyping approach more accessible than whole-genome sequencing. In this study, we developed an automated algorithm to specifically identify a wide range of mutations in the rpoB RRDR by utilizing the pattern of the Tm of the 4 probes within the 9 windows generated by the Ultra assay. The algorithm builds a RRDR mutation-specific “Tm signature” reference library from a set of known mutations and then identifies the RRDR genotype of an unknown sample by measuring the Tm distances between the test sample and the reference Tm values. Validated using a set of clinical isolates, the algorithm correctly identified RRDR genotypes of 93% samples with a wide range of rpoB single and double mutations. Our analytical approach showed a great potential for fast RRDR mutation identification and may also be used as a stand-alone method for ruling out relapse or transmission between patients. The algorithm can be further modified and optimized for higher accuracy as more Ultra data become available.

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