title: Predominance of Beijing genotype in extensively drug resistant Mycobacterium tuberculosis isolates from a tertiary care hospital in New Delhi, India.
abstract: Out of a total of 311 Mycobacterium tuberculosis isolates from sputum specimens subjected to first- and second-line drug-susceptibility testing (DST) at a hospital serving as a referral center for chronic tuberculosis (TB) cases in New Delhi, 232/311 (74.6%) isolates were found to be resistant to isoniazid and rifampicin. Among multidrug-resistant (MDR) isolates, 119/232 (51.3%) were resistant to four first-line drugs (streptomycin, isoniazid, rifampicin and ethambutol). Mono-resistance to isoniazid was observed in 18 (5.7%) isolates, while none of the isolates tested showed mono-resistance to rifampicin. 50/232 (21.5%) isolates met the definition of extensively drug resistant (XDR) TB, i.e., additional resistance to a fluoroquinolone and at least one of the three injectable second-line drugs: kanamycin, capreomycin, or amikacin. Spoligotyping of the XDR-TB isolates revealed 14 patterns; 39/50 (78%) isolates being grouped in three clusters vs. 11/50 (22%) isolates being unique. SIT1/Beijing represented the largest cluster (n=21, 42%), followed by SIT26/CAS1-Delhi (n=10, 20%) and SIT 53/T1 (n=8 isolates; 16%). This study corroborates recent observations from North India suggesting that both Beijing and CAS1-Delhi lineages constitute the bulk of XDR-TB isolates that are disseminating rapidly across a large geographical region in and around the capital city of India.
authors.affiliation: Department of Microbiology, Lala Ram Sarup Institute of Tuberculosis and Respiratory Diseases, Sri Aurobindo Marg, New Delhi 110030, India. Electronic address: arojyoti@gmail.com.
authors.forename: Jyoti
authors.initials: J
authors.lastname: Arora
authors.affiliation: Department of Microbiology, Lala Ram Sarup Institute of Tuberculosis and Respiratory Diseases, Sri Aurobindo Marg, New Delhi 110030, India. Electronic address: mnprtbhalla@yahoo.com.
authors.forename: Manpreet
authors.initials: M
authors.lastname: Bhalla
authors.affiliation: Department of Microbiology, Lala Ram Sarup Institute of Tuberculosis and Respiratory Diseases, Sri Aurobindo Marg, New Delhi 110030, India. Electronic address: sidiqueezeeshan@yahoo.co.in.
authors.forename: Zeeshan
authors.initials: Z
authors.lastname: Sidiq
authors.affiliation: Department of Microbiology, Lala Ram Sarup Institute of Tuberculosis and Respiratory Diseases, Sri Aurobindo Marg, New Delhi 110030, India. Electronic address: prabhalal@gmail.com.
authors.forename: Prabha
authors.initials: P
authors.lastname: Lal
authors.affiliation: Department of Microbiology, Lala Ram Sarup Institute of Tuberculosis and Respiratory Diseases, Sri Aurobindo Marg, New Delhi 110030, India. Electronic address: dir.lrsi@gmail.com.
authors.forename: Digamber
authors.initials: D
authors.lastname: Behera
authors.affiliation: WHO Supranational TB Reference Laboratory, TB & Mycobacteria Unit, Institut Pasteur de la Guadeloupe, Abymes, France. Electronic address: nrastogi@pasteur-guadeloupe.fr.
authors.forename: Nalin
authors.initials: N
authors.lastname: Rastogi
authors.affiliation: Department of Microbiology, Lala Ram Sarup Institute of Tuberculosis and Respiratory Diseases, Sri Aurobindo Marg, New Delhi 110030, India. Electronic address: tbmicro@gmail.com.
authors.forename: Vithal Prasad
authors.initials: VP
authors.lastname: Myneedu
keywords: Extensively drug resistant TB; Multidrug-resistant TB; Mycobacterium tuberculosis; Spoligotyping