Old drugs show promise in fighting TB

WASHINGTON (AP) — Scientists might have found a way to deal drug-resistant tuberculosis a one-two punch using two old, safe antibiotics — and studies in ill patients could begin later this year.

TB is one of the world’s oldest killers, and the lung disease still claims the lives of more than 1.5 million people globally every year. The bacteria that cause TB are fast becoming impervious to many treatments, drug resistance that is seen worldwide but is a particular problem in parts of Asia and Africa. While typically the TB doesn’t respond to two top treatments, an emerging threat is so-called extensively drug-resistant disease, or XDR-TB, that is virtually untreatable by remaining options.

So researchers are frantically hunting new approaches, including taking a fresh look at some old drugs. TB bacteria contain a certain enzyme that renders the penicillin family of antibiotics drugs useless.

“It chews them up and spits them out and they never get to see their target,” explained biochemist John Blanchard of the Albert Einstein School of Medicine.

But there are different antibiotics that can block that enzyme, called beta-lactamase. One, named clavulanate, has long been sold as part of the two-drug Augmentin combination that’s widely used for various children’s infections.

So Blanchard’s team tested whether administering clavulanate might make TB vulnerable to other antibiotics — and found a combination that in laboratory tests blocked the growth of 13 different drug-resistant TB strains.The combo: Clavul