ScienceDaily (Oct. 9, 1998) — Groundbreaking work to alter penicillin's structure and make it effective against antibiotic-resistant strains of bacteria has been reported in the October 9, 1998 Web edition of The Journal of Organic Chemistry, published by the American Chemical Society, the world's largest scientific society. The researchers say their prototype structure offers a "checkmate stratagem" against resistant bacteria.

Penicillin's effectiveness as an antibiotic has diminished since its widespread introduction in the 1940s, due to the ability of various bacteria to develop resistance to the drug. Researchers at the University of Limerick in Ireland have taken a major first step forward by developing a "unique modification to the penicillin structure," according to Timothy Smyth, Ph.D., lead author of the report.

Some bacteria are able to negate penicillin's infection-fighting properties by producing enzymes that cleave, or cut, a critical part of the penicillin molecule. To counter this, the typical response is to combine the penicillin with a chemical substance that inhibits the action of the enzymes. After a while, the bacteria develop additional resistance to the new substance and render the updated penicillin version ineffective.

The Irish research team has produced a prototype penicillin structure that works by incorporating a unique fragment to the penicillin molecule, which is fatal to bacteria and specifically activated only when a bacterium attempts to cleave the drug's molecular structure. Any bacterium that does not produce cleaving enzymes would still be killed off by the normal action of the intact penicillin.

While Smyth acknowledges "there is some way to go yet to deliver a therapeutically useful drug," he says the work "represents the delineation and implementation of the first steps toward realizing a new approach to combat bacterial resistance to antibiotics."

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