There is an alarmingly high burden of drug-resistant tuberculosis (DR-TB) among HIV-positive patients at antiretroviral therapy (ART) centres in Mumbai, according to a new study by the international medical humanitarian organisation Médecins Sans Frontières (MSF).

The findings reinforce the need for national health authorities to ensure timely diagnosis of DR-TB, especially for vulnerable populations and including people living with HIV, in order to curb primary transmission.

The study, published in PLoS One, is the first to look at the DR-TB burden amongst attendees of ART centres in high HIV-burden settings in Mumbai. Conducted in collaboration with the national health authorities in Mumbai between February 2013 and January 2014, attendees at seven large-scale ART centres were screened during more than 14,000 visits, and the sputum of 1,724 patients with TB symptoms was collected.  The study reveals the proportion of DR-TB to be 25 per cent among new cases of TB and 44 per cent among previously treated TB cases.
 
The study raises concerns, as it provides evidence that primary transmission is the cause of DR-TB in as many as one in four newly-diagnosed TB patients. These patients were exposed to DR-TB mycobacterium either in their communities or during their visits to health facilities as they have no previous records of receiving treatment for TB.

“In ‘hot-spots’ such as the slums of Mumbai, and among vulnerable groups such as people living with HIV, the DR-TB epidemic may be driven by primary transmission, rather than simply by a lack of adherence to TB treatment,” says Dr Petros Isaakidis, MSF principal investigator of the study. “The government needs to pay more attention to primary transmission of DR-TB, particularly in settings of high HIV prevalence and rapid TB spread. Promptly diagnosing and treating DR-TB is the solution to curb primary transmission.”

The data highlights the urgent need to address DR-TB among people living with HIV by systematically offering screening, drug susceptibility testing (DST) and access to treatment based on actual resistance patterns.

“We need to urgently prevent transmission of DR-TB to others. With DR-TB, treatment is prevention, and these findings should lead to a stronger focus on diagnostics and treatment of DR-TB, particularly in high HIV-prevalent settings,” says Eldred Tellis of the Mumbai AIDS Forum. “This is in addition to the fact that health authorities cannot afford to neglect TB infection control in overcrowded healthcare facilities like ART centres.”

“This study comes at the right time. Studies like this are complementary to the national survey and are essential to get a close-up picture of the DR-TB epidemic in ‘hot-spots’ and marginalised populations,” says Dr Arun Bamne, co-author of the study and former executive health officer of Mumbai’s Public Health Department. “Such studies will help shape the national response with specific interventions for those populations most at risk of getting DR-TB.”