Diagnosis of Multi-drug Resistant Tuberculosis Mutations Using Hain Line Probe Assay and GeneXpert: A Study Done in Zimbabwe
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Date
2015
Journal Title
Journal ISSN
Volume Title
Publisher
SCIENCEDOMAIN international
Abstract
Background and Aims: Tuberculosis (TB) is a global public health problem and one of the leading causes of death. Worldwide, 31% of all estimated new TB cases are from Africa. Zimbabwe is one of the 22 high TB burden countries. Multi-drug resistant TB (MDR-TB) poses challenges in TB control, hence the need for rapid laboratory diagnosis of MDR-TB for optimal treatment and reducing spread. The study aim was to investigate genetic mutations associated with MDR-TB isolates from various Harare clinics using the GeneXpert MTB/RIF® by Cepheid and Genotype MTBDRplus, to improve the diagnosis and management of MDR-TB.
Methods: Samples from adults aged 16 years and older, recruited from several polyclinics in the
southern suburbs of Harare were used for our study. All laboratory tests prior to this study had
been carried out at Biomedical research and training institute’s level three bio-safety TB laboratory
from January 2008-August 2012. Ethical approval was sought from BRTI Institutional review board.
A total of 69 (37 MDR-TB and 32 non MDR-TB) archived isolates processed on Genotype
MTBDRplus (Hains) and corresponding 39 sputum were processed on the GeneXpert. Mutations
on rpoB, katG and inhA genes were observed. The gold standard was culture. Diagnostic accuracy
of both methods and their level of agreement were calculated.
Results: Of the 37/69 isolates screened by culture for MDR-TB, 88.4% were confirmed by
MTBDR® plus line probe assay (Hains). Within the 39 isolates tested using the Xpert MTB/RIF
(GeneXpert) assay 12 were true MDR-TB. Over 8 single nucleotide polymorphisms were observed
on the three genes conferring Rifampicin and Isoniazide drug resistance. The Hains and
GeneXpert had an almost perfect agreement with a kappa value of 0.82.
Conclusion: Genetic markers can be used in the diagnosis of MDR-TB, to complement
phenotypic methods such as culture. Using the commercial methods, Hains and GeneXpert, 88.4-
94.2% of drug resistance maybe detected. Furthermore, we recommend sequencing so as to
identify novel mutations and to design a kit that is custom made for the population.
Description
Journal Article
Keywords
Tuberculosis, MDR-TB, molecular diagnosis, Zimbabwe, GeneXpert; hains.
Citation
Dhlamini, Z., 2015. Diagnosis of Multi-drug Resistant Tuberculosis Mutations Using Hain Line Probe Assay and GeneXpert: A Study Done in Zimbabwe. British Journal of Medicine & Medical Research. 5(8): 1044-1052.