Background

Tuberculosis (TB) requires drug treatment for several months to be cured, possibly because some of the TB-causing bacteria are tolerant to the drugs and continue to survive when the rest of the bacteria are killed. These tolerant TB bacteria may delay the cure of TB and may also lead to the reappearance of TB when treatment is stopped.

The number of tolerant bacteria and the factors leading to tolerance are poorly defined. It is important to understand tolerance better as it may lead to new drugs that overcome tolerance and thereby shorten the treatment of TB.