India: Multi-drug resistant TB looms over Chennai
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.
"We have seen more than a dozen cases in Tamil Nadu since July. It makes TB treatment extremely difficult," said NIRT director Soumya Swaminathan. Cocktail of antibiotics can cure TB.
Chennai: Tuberculosis, caused by the organism Mycobacterium tuberculosis, can be fatal but is curable with a cocktail of antibiotics. But new strains of the organism with multi-drug resistance, which have surfaced in many places across the globe, have left physicians dreading the possibility that a TB 'superbug' could prove completely resistant to all drugs currently available.
When patients are resistant to the first line of treatment, they are labelled multidrug resistant (MDR-TB ). Such people are given the second line drugs that are more expensive and have greater side-effects . Patients who become resistant to second line of drugs fall into the extensively drug resistant (XDR-TB ) category.
While India has data on MDR-TB and XDR-TB , there has been no agreement on the new drug resistant strain. A group of Mumbai doctors who first found the strain in January 2012 call it totally drug resistant (TDR) tuberculosis, but WHO prefers to identify it as an advanced stage of extreme drug resistance (XDR+).
Scientists unanimously agree that the strain is as deadly as a superbug. Since July , NIRT has been screening patients in three districts of northern Tamil Nadu — Chennai, Tiruvallur and Kancheepuram — for the totally drug resistant strain. Patients who failed the first line of treatment , those who dropped out of the programme , HIV-infected people and those who had a relapse of the bacterial infection were tested for drug resistance. The results, they said, were as expected.
The Centre will soon begin a nationwide survey to determine the incidence of the most complicated strain of tuberculosis, advanced extensively drug resistant tuberculosis(XDR-TB). The National Institute of Tuberculosis in Bangalore is drawing up a protocol for the survey which will be conducted by three government-run institutes in the country. When the first instances of the strain, which is resistant to all known antibiotics, being detected in India were reported in Mumbai in January, the government went into denial mode. After doctors across the country said they had treated TB patients who did not respond to drugs, the government confirmed that the drug-resistant strain had arrived in India.
"We cannot say it is totally drug resistant," said Dr Ashok Kumar who heads the revised national TB control programme in India. "We only have piecemeal information now. We need comprehensive data. That's why we are planning a nationwide survey."
The survey will be carried out by National Institute of Tuberculosis , Bangalore, National Institute for Tuberculosis Research , Chennai, and LRS Institute of Tuberculosis and Respiratory Diseases, Delhi. Tuberculosis is a bacterial disease caused by the organism, Mycobacterium tuberculosis. Advanced extensively drug resistant TB (usually abbreviated to XXDR TB or XDR TB) is also referred to as totally drug resistant TB. This strain is resistant to all first and second line TB drugs.
In 2007, Italy reported two cases of XXDR TB in 2003. Earlier this year, infectious diseases expert Dr Zarir Udwadia of Hinduja Hospital, Mumbai, found a dozen cases that were totally resistant to known drugs. "We have little to offer these patients except for drastic surgery and medication for relief ," he said.
St John's National Academy of Health Sciences, Bangalore, has reported three such cases and All India Institute of Medical Sciences, New Delhi, has had two. Experts said many of these patients had received erratic, unsupervised second line drugs in incorrect doses from multiple practitioners.
NIRT director Soumya Swaminathan said that though many doctors had clinically confirmed such cases, the strain's "total drug resistance" is difficult to confirm in a lab. "Adequate tests have not been done to draw conclusion that the strain is drug resistant," she said. "This is a reason why WHO does not call it totally resistant."
A senior scientist at NIT said the institute is drawing up a protocol that will be acceptable to the scientific community. "We are conducting brainstorming sessions and discussions with researchers abroad. We will be able start the survey before the end of the year," he said.
When the bacterium is exposed to the drug but is not killed, it develops resistance to the medicine . "Drug resistance slows cure and increases rate of transmission , said Dr Nalini Krishnan, who heads REACH, a Chennai-based NGO. "People infected are likely to spread the strain, making it difficult for us to control the infection."
DECODING THE VIRUS
What is tuberculosis?
Tuberculosis or TB is a communicable disease caused by bacillus mycobacterium tuberculosis. It can be fatal, but is curable with a cocktail of antibiotics.
Types of drug resistance
Multi-drug-resistant tuberculosis or MDR-TB is a form of the disease, which is resistant to isoniazid (INH) and rifampicin (RMP), the two most powerful first-line anti-TB drugs. Extensively drug-resistant tuberculosis or XDR-TB is a form caused by bacteria that are resistant to anti-TB drugs. Total drug-resistant tuberculosis or TDRTB is a relatively new strain of TB reported, which is resistant to the 12 anti-TB drugs.
How does one get drug-resistant TB?
Drug resistance occurs due to the improper use of antibiotics among TB patients. This is a result of a number of actions, including administration of improper treatment regimens by healthcare workers and failure to ensure that patients complete the whole course of treatment
Silent killer
Every year, India adds the largest number of people to the global TB population. The Union health ministry in 2009 estimated that of the 94 lakh cases reported globally 20 lakh were from India WHO records show that of the 11 lakh deaths reported in 2010, more than 3 lakh were from India, the largest number recorded, followed by Bangladesh, Indonesia and Pakistan.
The Times of India
