January 22, 2007

Requiem for Magic Bullets

Steve Silberman:
The golden age of antibiotics began in 1944 with the widespread use of penicillin in Europe, which saved many thousands of lives during World War II. But the first sign that this new era of easily treatable bacterial infections would not last appeared just a couple of years later, with the emergence of penicillin-resistant strains of Staphylococcus aureus, a bacterium responsible for a wide variety of ailments, from skin infections to fatal pneumonia.

By 1950, 40 percent of the staph strains in hospitals had already become immune to the drug. Now a form of staph known as methicillin-resistant Staph aureus, or MRSA, which is resistant to nearly every known antibiotic, is responsible for the majority of tens of thousands of deaths a year from infections picked up in U.S. hospitals alone.

Bacteria develop immunity to antibiotics by rapidly evolving genetic defenses against the drugs or by acquiring pieces of DNA and RNA from organisms that are already resistant -- even from other bacterial species. Bacterial pathogens that have learned how to survive in hospitals have an evolutionary advantage, because there are plenty of other resistant organisms in the environment from which they can borrow resistance factors.
Posted by James Zellmer at January 22, 2007 7:55 AM | Subscribe to this site via RSS:
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