Research May Aid Antibiotic Resistance Control

September 21, 2005 — 

Research reported in the Proceedings of the National Academy of Sciences the week of September 19, 2005 identifies mutations in beta-lactamase enzymes that enhance bacterial resistance to a broad spectrum of beta-lactam antibiotics such as penicillin and cephalosporins.

The scientists used a lactamase gene very similar to that found in Bacillus anthracis, the bacteria which causes anthrax. They introduced mutations into the gene responsible for the bacterial resistance enzyme and increased the evolutionary pressure on the enzyme by using high concentrations of cephalexin.

The study identified four mutations in the evolved enzyme that enabled resistance to an antibiotic dose 64 times higher than the dose that routinely destroys susceptible bacteria. The evolved lactamase also inactivated 7 other cephalosporins according to the report. The implication of this research is that this enzyme represents the possible future evolution of beta-lactamase resistance. The hope is that, by better understanding the evolution of these enzymes, scientists could develop advanced enzyme inhibitors to prevent the development of enzyme-mediated resistance.

Source:
Proceedings of the National Academy of Sciences
http://www.pnas.org/cgi/gca?sendit=Get+All+Checked+Abstract%28s%29&gca=0503495102v1
http://www.hhmi.org/news/vila.html