Study Finds Vitamin C Kills Drug-Resistant Tuberculosisselfnews Post TB is caused by infection with the bacterium M. tuberculosis. In 2011, TB sickened some 8.7 million people and took some 1.4 million lives, according to the World Health Organization. Infections that fail to respond to TB drugs are a growing problem: About 650,000 people worldwide now have multi-drug-resistant TB (MDR-TB), 9 percent of whom have extensively drug-resistant TB (XDR-TB).TB is especially acute in low and middle income countries, which account for more than 95 percent of TB-related deaths, according to the World Health Organization. Dr. Jacobs and his colleagues observed that isoniazid-resistant TB bacteria were deficient in a molecule called mycothiol. We hypothesized that TB bacteria that cant make mycothiol might contain more cysteine, an amino acid, said Dr. Jacobs. So, we predicted that if we added isoniazid and cysteine to isoniazid-sensitive M. tuberculosis in culture, the bacteria would develop resistance. Instead, we ended up killing off the culture something totally unexpected. The Einstein team suspected that cysteine was helping to kill TB bacteria by acting as a reducing agent that triggers the production of reactive oxygen species (sometimes called free radicals), which can damage DNA. We predicted that if we added isoniazid and cysteine to isoniazid-sensitive M. tuberculosis in culture, the bacteria would develop resistance. Instead, we ended up killing off the culture something totally unexpected. William Jacobs, Jr., Ph.D. To test this hypothesis, we repeated the experiment using isoniazid and a different reducing agent vitamin C, said Dr. Jacobs. The combination of isoniazid and vitamin C sterilized the M. tuberculosis culture. We were then amazed to discover that vitamin C by itself not only sterilized the drug-susceptible TB, but also sterilized MDR-TB and XDR-TB strains. To justify testing vitamin C in a clinical trial, Dr. Jacobs needed to find the molecular mechanism by which vitamin C exerted its lethal effect. More research produced the answer: Vitamin C induced what is known as a Fenton reaction, causing iron to react with other molecules to create reactive oxygen species that kill the TB bacteria. We dont know whether vitamin C will work in humans, but we now have a rational basis for doing a clinical trial, said Dr. Jacobs. It also helps that we know vitamin C is inexpensive, widely available and very safe to use. At the very least, this work shows us a new mechanism that we can exploit to attack TB. The paper is titled, Mycobacterium tuberculosis is extraordinarily sensitive to killing by a vitamin C-induced Fenton reaction. The other contributors are Catherine Vilcheze, Ph.D., Travis Hartman and Brian Weinrick, Ph.D., all at Einstein. The study was supported by a grant (AI26170) from National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health. The authors declare no conflict of interest. Deirdre Branley Press Release Source Read other articles and announcements by selfnews Post Here 