Irish scientists have made a ground-breaking discovery which could reinstate penicillin as the single most important drug in the fight against bacterial infection.
A team at the University of Limerick found a way to modify the antibiotic, which tricks a bacterium displaying resistance to it, and in the process kills it. Drug resistance has been one of the biggest bugbears of medical treatment in the late 20th century, and the discovery opens up the possibility of a new form of penicillin which could lead the fight-back against antibiotic-resistant bacteria.
"It is certainly a very dramatic finding. We got a bit lucky," the leader of the research team, Dr Timothy Smyth, told The Irish Times last night.
The new technique for modifying the structure of penicillin has been described as "essentially a boobytrap" that is triggered when a bacterium deploys its biological defences against the drug. If a bacterium is not resistant, the penicillin works in the normal way. But if it is resistant, the booby-trap is sprung. In both instances the bacterium is destroyed.
Penicillins were the first group of antibiotics, discovered by Sir Alexander Fleming in 1929. But since their widespread introduction in the 1940s, their effectiveness has been gradually undermined by bacterial resistance. Drug resistance, especially in latter years, has been the bane of medical practitioners and pharmaceutical companies forced to spend colossal budgets in attempting to devise new drug forms.
The team made its discovery "almost by accident" while researching penicillin, Dr Smyth said last night.
The researchers hit on a way to attach an extra molecule to penicillin which is easily sliced off by a bacterial enzyme. This molecule can be designed to become lethally toxic to the bacterium as soon as it is detached. Thus by attempting to resist penicillin the bacterium seals its own fate.
"When the use of penicillin became widespread bacteria started producing a whole battery of defence enzymes, and there are about 200 varieties in all. What we have been able to do is to exploit a specific mechanism of resistance by modifying the structure of penicillin" Dr Smyth said. The discovery was announced in the US yesterday by the American Chemical Society, coinciding with the research being published in the Internet edition of its Journal of Organic Chemistry.
