Publication: katG (SER 315 THR) Gene Mutation in Isoniazid Resistant Mycobacterium tuberculosis
Date
2011
Journal Title
Journal ISSN
Volume Title
Publisher
Kathmandu University
Abstract
ABSTRACT
Background
Isoniazid (INH) together with Rifampicin (RFP) forms the cornerstone of a short
chemotherapy course for tuberculosis (TB) treatment. Mutation at codon 315 of
katG gene is most prevalent in isoniazid resistant Mycobacterium tuberculosis
(MTB) and is high in area with high TB incidence. Polymerase Chain Reaction
Restriction Fragment Length Polymorphism (PCR-RFLP) has been found to be a
reliable and effective tool for the identification of the specific gene alteration.
Objective
The objective of this study was to screen Ser315Thr mutation of KatG gene of INH
resistant MTB strain by PCR-RFLP technique.
Methods
Altogether 37 INHr MTB isolates obtained from German Nepal Tuberculosis Project
(GENETUP) Kathmandu Nepal was included in the study. Deoxyribonucleic Acid
(DNA) extraction was performed according to protocol of SORPOCLEAN™ from the
culture isolates. Amplification of the fragment with katG codon 315 was performed
in a Biometra Thermocycler using primers. The amplified fragment was cleaved with
MspI. The restriction fragments obtained were electrophoresed in a 2% agarose gel
and were visualized using transilluminator.
Results
The katG Ser315Thr mutation was observed in 23 (62.2%) out of 37 INH resistant
isolates. The drug susceptibility profile of INHr MTB isolates showed all isolates
to be resistant to INH and RFP whereas 26 and 27 MTB isolates were resistant
to Ethambutol (EMB) and Streptomycin (S) respectively. Seventeen (17) patients
were harbouring katG gene mutated strain among Ethambutol and Streptomycin
resistant cases.
Conclusion
The study identified high prevalence of Ser315Thr mutation in katG. The isolates
harbouring this mutation were also simultaneously resistant to RFP. Ser315Th could
be a potential genetic marker for predicting MDR-TB.
KEY WORDS
Isoniazid resistant MTB, katG gene, Mycobacterium tuberculosis, PCR-RFLP,
mutation.
Description
Marahatta SB,1 Gautam S,2 Dhital S,2 Pote N,2 Jha AK,2 Mahato R,1 Mishra S,3 Poudel BH,4 Ramasoota P,5 Kaewkungwal J,6 Singhasivanon P6
1 Department of Community Medicine, Kathmandu University School of Medical Sciences University, Nepal
2Department of Laboratory Medicine, Nobel College, Pokhara University, Kathmandu, Nepal
3 Department of Microbiology, Institute of Medicine, Tribhuvan University, Kathmandu, Nepal
4Department of Biotechnology Tribhuvan University Kathmandu Nepal
5Department of Social and Environmental Medicine, Faculty of Tropical Medicine Mahidol University,Thailand
6Department of Tropical Hygiene, Faculty of Tropical Medicine Mahidol University, Thailand