|LETTER TO EDITOR
|Year : 2018 | Volume
| Issue : 2 | Page : 161-162
High percentage of Beijing genotype among extensively drug-resistant tuberculosis isolates in Delhi Region
Zeeshan Sidiq1, M Hanif2, Indrani Jadhav3, Kamal Kishore Chopra2
1 School of Life Sciences, Jaipur National University, Jaipur, Rajasthan; New Delhi Tuberculosis Centre, New Delhi, India
2 New Delhi Tuberculosis Centre, New Delhi, India
3 School of Life Sciences, Jaipur National University, Jaipur, Rajasthan, India
|Date of Web Publication||14-Jun-2018|
Dr. M Hanif
New Delhi Tuberculosis Centre, Jawaharlal Nehru Marg, Delhi Gate, New Delhi - 110 002
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Sidiq Z, Hanif M, Jadhav I, Chopra KK. High percentage of Beijing genotype among extensively drug-resistant tuberculosis isolates in Delhi Region. Biomed Biotechnol Res J 2018;2:161-2
|How to cite this URL:|
Sidiq Z, Hanif M, Jadhav I, Chopra KK. High percentage of Beijing genotype among extensively drug-resistant tuberculosis isolates in Delhi Region. Biomed Biotechnol Res J [serial online] 2018 [cited 2021 Oct 26];2:161-2. Available from: https://www.bmbtrj.org/text.asp?2018/2/2/161/234461
India is one of the high-burden countries for tuberculosis (TB) as well as drug-resistant (DR) TB. India accounted for an estimated 147,000 patients out of 601,000 cases of multidrug-resistant TB estimated to have occurred among the notified cases of TB across the globe in 2016. In addition, 2650 cases of extensively drug-resistant (XDR) TB were also reported to have occurred. Patients infected with strains resistant to multiple drugs are less likely to be cured. Previous work on the population dynamics of drug resistance has shown that the fitness of DR strains is a key determinant of the future burden of DR-TB. Hence, understanding of the disease transmission dynamics becomes important in order to contain the epidemics of DR-TB. Molecular genotyping methods such as Spoligotyping of Mycobacterium tuberculosis strains worldwide have led to the identification of strain families or lineages, which are associated with DR-TB.
At the New Delhi Tuberculosis Centre which is a State TB Training and Demonstration Centre and is also functioning as an intermediate reference laboratory providing support to Delhi state Revised National Tuberculosis Control Programme for the diagnosis of DR-TB, we performed Spoligotyping of XDR-TB strains identified among presumptive DR-TB patients tested during January to August 2017. Spoligotyping of 20 XDR-TB isolates identified among the 3400 presumptive DR-TB patients identified a total of six different patterns. Five patterns corresponded to shared types (SITs) in Spoligotyping database, and one pattern belonged to orphan strains. The largest cluster was SIT1/Beijing (10/20 or 50%), followed by SIT26/CAS1-Delhi (6/20 or 30%), SIT53/T1 (1/20 or 2.0%), SIT54/T1 (1/20 or 2.0%) and SIT11/EAI3_IND (1/20 02 2.0%). Taken as a lineage irrespective of SIT designations, Beijing was the most predominant clade (n = 10), followed by CAS (n = 6), ill-defined T (n = 2), and EAI (n = 1) whereas one isolate showed unknown lineage signatures.
We found SIT1/Beijing and SIT26/CAS1-Delhi to be predominant among the XDR isolates in Delhi region, accounting for 80% of the total isolates spoligotyped. Previous studies from Delhi have reported the isolation of these two clads with varying percentages. It is generally accepted that Beijing genotypes have a particular propensity to acquire drug resistance, and once established, resistance could encourage spread if it delays effective treatment. In addition, these strains have mutation in their putative mutator genes, which suggests adaptability and hence reduced fitness due to resistance is not common. Considering the fact that Beijing genotype is the major cause of outbreaks involving drug-resistant variants worldwide  and is highly associated with drug resistance, our findings are a major cause of concern for health authorities.
In conclusion, the association of XDR-TB with these prevalent clades poses a potential threat to TB control in India. Emphasis should be laid on characterization of the clades with regard to their transmissibility and rapid diagnosis of drug resistance in order to curtail chains of transmission and strengthening the TB control program in India, especially when the country is aiming to end TB in the near future.
The authors gratefully acknowledge the technical support from Dr. Kaushal, Dr. Vasim, Dr. Himanshu and Ms. Srishti Sharma.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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