This is what experts heard today at the bi-annual meeting of the Society of General Microbiology at the University of East Anglia in Britain.

Dr. Lawrence Wayne of the Department of Veterans Affairs Medical Center, Long Beach, California, says, "We have had powerful drugs to treat tuberculosis for over 50 years, but we have failed to eradicate the disease.

"This is due in part to socioeconomic factors as well as to AIDS, which destroys our immunity to the tubercule bacteria, but also because the bacteria can go into a dormant state in our bodies, surviving for months or years without multiplying, protected from the anti-tuberculosis drugs."

According to Dr. Wayne, the tubercule bacteria adapt their biochemistry to conserve energy, which allows them to survive without any oxygen, although they usually need at least 10% oxygen to grow.

As inflamed and infected tissues slowly run out of oxygen, the bacteria stop reproducing and become dormant. The bacteria can also switch to alternative energy sources, reduce their need to make proteins, and protect their essential enzymes from breaking down.

Dr. Wayne says, "As medical scientists gain further genetic information about these adaptations, it should be possible to design drugs that will interfere with them and prevent the bacteria from surviving in oxygen depleted tissues, solving the problem of latent tuberculosis disease."

(Editor's Note: A lengthier review of the conference presentation, "Nonreplicating persistence of Mycobacterium tuberculosis," in collaboration with C. Sohaskey, is in press in the 2001 edition of Annual Reviews of Microbiology.)

[Contact: Dr. Lawrence Wayne]

10-Sep-2001