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. 2016 Mar;143(3):341-7.
doi: 10.4103/0971-5916.182625.

A study on pre-XDR & XDR tuberculosis & their prevalent genotypes in clinical isolates of Mycobacterium tuberculosis in north India

Parul Singhal  1 , Pratima Dixit  1 , Pooja Singh  1 , Indu Jaiswal  1 , Mastan Singh  1 , Amita Jain  1
Affiliations

A study on pre-XDR & XDR tuberculosis & their prevalent genotypes in clinical isolates of Mycobacterium tuberculosis in north India

Parul Singhal et al. Indian J Med Res. 2016 Mar.

Abstract

Background & objectives: Pre-extensively drug resistant (pre-XDR) and extensively drug resistant tuberculosis (XDR-TB) have been areas of growing concern, and are posing threat to global efforts of TB control. The present study was planned to study the presence of pre-XDR and XDR Mycobacterium tuberculosis and their genotypes in clinical isolates obtained from previously treated cases of pulmonary TB.

Methods: A total of 219 isolates obtained from previously treated cases of pulmonary TB were subjected to first-line (streptomycin, isoniazid, rifampicin and ethambutol) and second-line (ofloxacin, kanamycin, capreomycin and amikacin) drug susceptibility testing on solid Lowenstein-Jensen medium by proportion method. Genotyping was done for pre-XDR and XDR-TB isolates using 12 loci Mycobacterial Interspersed Repetitive Units-Variable Number Tandem Repeats (MIRU-VNTR).

Results: Multi-drug resistance was observed in 39.7 per cent (87/219) isolates. pre-XDR and XDR M. tuberculosis isolates amongst 87 multi-drug resistant (MDR) TB isolates were 43 (49.4%) and 10 (11.4%), respectively. Two most dominant genotypes among pre-XDR and XDR M. tuberculosis isolates were Beijing and Delhi/CAS types.

Interpretation & conclusions: Resistance to second-line anti-tubercular drugs should be routinely assessed in areas endemic for TB. Similar genotype patterns were seen in pre-XDR and XDR-TB isolates. Beijing and Delhi/CAS were predominant genotypes.

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Conflict of interest statement

Conflicts of Interest: None.

Figures

Fig. 1
Fig. 1
Dendogram showing MIRU-VNTR (Mycobacterial Interspersed Repetitive Units - Variable Number Tandem Repeats) analysis of pre-XDR M. tuberculosis isolates (n=43). LAM, Latin American and Mediterranean.
Fig. 2
Fig. 2
Dendogram showing MIRU-VNTR (Mycobacterial Interspesred Repetitive Units - Variable Number Tandem Repeats) analysis of XDR M. tuberculosis isolates (n=10).
See this image and copyright information in PMC

References

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