快猫短视频

A BREAKTHROUGH in understanding how tuberculosis lies low in the body could
lead to a fast and effective cure for the disease.

TB is a growing threat as drug-resistant forms emerge. At present, a course
of antibiotics lasting between 6 and 12 months is needed to cure TB. It takes
this long because the existing drugs target rapidly dividing bacteria, rather
than the slow-growing ones responsible for persistent infections.

But when John McKinney, who is now at the Rockefeller University in New York,
reviewed research done in the 1950s, he was intrigued by a study of bacteria
taken from long-infected lung tissue. Unlike Mycobacterium tuberculosis
grown in the lab, these bacteria got their energy from fatty acids, not
sugars.

McKinney and his colleagues then targeted the pathway bacteria use to break
down fatty acids. They genetically engineered TB bacteria that lacked a key
enzyme called isocitrate lyase. When they infected mice with these mutant
bacteria, a normal infection developed but the animals鈥� immune systems were able
to clear the bacteria.

The results suggest that the M. tuberculosis bacterium alters its
metabolism to counter the immune system鈥檚 attack. McKinney and his collaborators
are now studying the structure of the enzyme and are developing drugs to inhibit
it. They hope to begin animal trials by the end of the year.

If all goes well, TB patients could soon get the drugs that target rapidly
growing bacteria along with another one that targets persistent bugs. This
one-two punch could eliminate the bacteria in weeks instead of months, McKinney
says.

鈥淚t would be wonderful to imagine that we could treat tuberculosis like any
other bacterial infection,鈥� says James Sacchettini, one of McKinney鈥檚
collaborators at Texas A&M University in College Station. 鈥淚f we could treat
tuberculosis in two to three weeks, I think we鈥檇 have a really good chance of
eradicating the disease.鈥�