Genetic diversity in clinical Mycobacterium tuberculosis isolates from Punjab.
METHODS
Two hospitals, Sri Guru Ram Das Institute of Medical Sciences and Research and the TB and Chest Hospital, Amritsar, Punjab.


OBJECTIVE
To explore genetic diversity among the clinical Mycobacterium tuberculosis isolates prevalent in Punjab.


METHODS
Fifty-six random clinical isolates of M. tuberculosis were cultured from the sputum specimens of pulmonary tuberculosis patients. DNA was extracted from cultured biomass and analysed using the mycobacterial interspersed repetitive units (MIRU) typing method.


RESULTS
MIRU typing of 51 isolates revealed 45 different patterns, with a combined Hunter-Gaston discriminatory index (HGDI) of 0.990. Five clinical isolates failed to amplify for one or more MIRUs and were excluded from the analysis. The remaining isolates were categorised in three groups based on the allelic heterogeneity of individual MIRUs. MIRU 10, 16, 26 and 31 were highly discriminant, with an HGDI value >0.6; MIRU 4, 23, 24, 39 and 40 were designated as moderately discriminant (HGDI value 0.6-0.3) and MIRU 2, 20 and 27 were poorly discriminant (HGDI value <0.3).


CONCLUSIONS
MIRU typing and the HGDI values revealed that M. tuberculosis strains from Punjab are genetically quite heterogeneous.
Sharma
R
R
Department of Molecular Biology and Biochemistry, Guru Nanak Dev University, Amritsar, India.
Kalyani
M
M
Kajal
N C
NC
Sarin
B C
BC
Sehajpal
P K
PK
D015373:Bacterial Typing Techniques; D004269:DNA, Bacterial / Q000032:analysis; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D007194:India / Q000453:epidemiology; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000302:isolation & purification; D013183:Sputum / Q000382:microbiology; D014397:Tuberculosis, Pulmonary / Q000453:epidemiology / Q000235:genetics / Q000382:microbiology*
D004269:DNA, Bacterial