PARIS – Extensively drug-resistant tuberculosis (XDR-TB) emerged and was widely transmitted in South Africa long before it was spotted by public health surveillance efforts, and at least a decade earlier than the first reported outbreak in 2005, a presentation Monday (July 24) showed. The start of the spread was concurrent with the steep rise in both HIV and TB incidence in the early 1990s.
The analysis of genomic sequencing of cases in KwaZulu-Natal provice, presented by Tyler Brown an infectious diseases fellow at Massachusetts General Hospital, was similar to that undertaken to determine the timing of the introduction of HIV into North America.
Extensively drug-resistant tuberculosis (XDR-TB) is defined as TB that is resistant to the two major anti-TB medications, isoniazid and rifampicin as well as two additional categories of TB drugs and has a mortality rate of 50 to 80 percent. South Africa has the highest rate of XDR-TB in the world with more than 1,000 cases reported in 2015.
“Evolution of drug resistance happens fast even in TB and whole genomic sequencing can be an important tool for early detection of emerging drug resistance,” Brown said. He called for immediate surveillance to monitor the potential emergence of resistance to the new medications, bedaquiline and delamanid. He also noted that HIV likely facilitated the introduction and spread of XDR-TB. “HIV treatment is likely a cornerstone to preventing further spread of XDR-TB,” he concluded.
Source: Science Speaks