segunda-feira, 27 de setembro de 2010

Penicilina, a maior descoberta Século XX

A penicilina foi a maior descoberta do século XX. Com isolamento desse antibiótico só aplicado para seres humanos em 1942. Veja a história completa da descoberta publicada no The Scientist

-By Cristina Luiggi
The Discovery of Penicillin, circa 1928
It was the wonder drug of the 20th century: A yellow liquid that seeps from the spores of the Penicillium fungal mold and contains a compound that shatters the cell walls of bacteria responsible for common diseases such as pneumonia, strep throat, scarlet fever, syphilis, and meningitis. With steep reductions in human mortality rates and drastic improvements in quality of life, penicillin may very well be one of mankind’s greatest discoveries.

Scottish doctor Alexander Fleming observed the mold killing his Staphylococcus cultures in late 1928 while working at St. Mary’s Hospital in London. But by the start of World War II, no one had figured out how to efficiently extract the active ingredient from Penicillium, whose concentration “is almost the same as gold in sea water,” says Robert Bud, Principal Curator of Medicine at The Science Museum in London and author of Penicillin: Triumph and Tragedy.
It wasn’t until the end of 1940 that doctors at Oxford University had collected enough penicillin to treat one person: a policeman who got blood poisoning from a small scratch on his face. Unfortunately, his intravenous treatment of penicillin used up the entire stock of the drug. Doctors tried recycling penicillin from his urine to continue his treatment, Bud says, but with barely one hundredth of a gram of antibiotic per gallon of urine, it simply wasn’t enough. The man died shortly after the penicillin ran out

In 1942, the Russians held the record for treating the most patients with the drug, Bud says, scraping the Penicillium off the walls of damp air raid shelters and rubbing the fungal juice directly onto affected areas. Two years later, researchers finally succeeded in mass-producing the antibiotic by growing a mutant Penicillium strain in corn starch liquor in large metal tanks—just in time to aid the thousands of soldiers who would be wounded on the beaches of Normandy on D-Day.
The wonder drug has lost some of its killer properties in the decades following its initial widespread use, with hospitals reporting penicillin-resistant infections as early as the mid-1940s. A new antibiotic called methicillin initially served as a good alternative, but bacteria have since evolved ways to circumvent methicillin’s deadly grip as well. Methicillin-resistant Staphylococcus aureus (MRSA) was responsible for around 20,000 deaths in the United States in 2005.

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