Extensively drug-resistant tuberculosis (XDR-TB) in HIV-positive people is “a reality in India”, according to a study published in the November edition of AIDS. In a nine month study period, investigators identified 54 HIV-positive individuals with TB, and four of these patients had XDR-TB. All four died within three months.
HIV and TB are major public health concerns and TB is the single biggest cause of death in HIV-positive patients around the world.
In 2004 approximately 4% of patients with TB had a strain of the disease with resistance to one or more key first-choice drugs used in its treatment (multidrug-resistant TB, or MDR-TB). This form of TB requires a longer duration of treatment with more-expensive and less-effective second-line drugs. Studies have shown a high prevalence of MDR-TB in HIV-positive individuals.
More recently, TB has been detected that has resistance to second-line drugs as well. Clusters of XDR-TB have been identified in HIV-positive patients and these patients have had a very poor prognosis.
India has a higher rate of MDR-TB than any country other than China, so investigators expected that the possibility that XDR-TB was present in the country was high.
A prospective study was therefore undertaken involving HIV-positive patients coinfected with TB who received care from the All India Institute of Medical Science in New Delhi.
The study was conducted between March and December 2006. During the study period, 54 HIV-positive patients were diagnosed with TB and 24 of these patients had culture-positive TB.
Drug sensitivity testing of specimens obtained from each of the 24 patients with culture-positive TB. This testing showed that twelve (50%) individuals had MDR-TB.
When samples from patients with MDR-TB were subjected to further tests it was established that four patients (33.3%) had XDR-TB. Three of these patients were men, and the mean CD4 cell count was 102 cells/mm3. All four patients died within 2.6 months of XDR-TB being diagnosed.
“Our preliminary findings suggest that XDR tuberculosis is a reality in India. Even though XDR tuberculosis in four (16.7%) out of 24 cases may not truly reflect the prevalence rate, it clearly shows that these patients carry an extremely high and rapid mortality rate”, comment the investigators.
They add, “this study also has significance in that from 54 patients [TB] was isolated in nine months only. We are continuing our work on XDR tuberculosis evaluation in HIV-positive and negative patients from both community and hospital settings.”
Singh S et al. High rate of extensively drug-resistant tuberculosis in Indian AIDS patients. AIDS 21: 2345 – 2347, 2007.