CHENNAI: The most feared form of drug-resistant tuberculosis has arrived in Chennai. Doctors at the National Institute for Research in Tuberculosis (NIRT) in Chennai report that they have since July treated a few TB patients who did not respond to any of the existing antibiotics for the disease. Some of the patients have died.

Researchers say they cannot as yet provide specific number of cases or the percentage of TB patients with the deadly strain of the disease, advanced extensively drug resistant tuberculosis (XDR-TB ). They say that they are still screening patients and analysing the results, but the institute confirmed instances of the strain.