Bacteria In Dirt May Be "Born" Resistant To Drugs
Bacteria that live in soil, a major source of wonder drugs such as penicillin, are surprisingly resistant to antibiotics and may provide clues for developing new medicines, according to a study. Researchers in Canada examined 480 types of soil-dwelling microbes and found every one to be resistant to at least six antibiotics such as penicillin and tetracycline, according to the report in the Dec. 20 issue of the journal Science. Two microbes resisted 15 of the 21 medicines tested. ``The frequency of high-level resistance seen in the study to antibiotics that have for decades served as gold-standard treatments, as well as those only recently approved for human use, is remarkable,'' wrote Vanessa D'Costa and three co-authors at McMaster University in Hamilton, Ontario. The researchers found that many soil bacteria produce enzymes that counter the effects of the drugs, rather than mutating to become resistant. Understanding the enzymes may help drug developers find means to overcome the resistance, the researchers said. The resistance mechanisms described in the study ``may provide the medicinal chemist with precious clues in the design of new antimicrobial agents,'' wrote Alexander Tomasz, a microbiologist at Rockefeller University in New York, in an accompanying commentary. Infections now considered trivial used to be fatal, before antibiotics were discovered to kill dangerous bacteria. As the microbes that cause human disease have mutated, many have become resistant to older drugs such as penicillin.