Cork: Modified nisin antibiotics show greater activity

Research lead

Researchers at University College Cork have altered different amino acids in nisin, an antimicrobial protein produced naturally by a bacterium called Lactococcus lactis, creating variants that possess greater activity than the parent molecule against a range of important clinical pathogens including methicillin-resistant Staphylococcus aureus, Vancomycin resistant Enterococci and Listeria monocytogenes.

Nisin is approved as a natural biopreservative in heat-treated and low-pH foods. It has a long record of safe use and is one of only a few such compounds to have been applied commercially.

Nisin is the active ingredient in a number of commercial products that are used in the treatment of bovine mastitis and enhanced nisin derivatives with greater specific activity against this infection would be of value.

Similarly, using nisin variants that are active against Listeria would be significant as this bacterium is among the most naturally nisin-resistant pathogens.

Researcher Des Field said, “Nisin has the potential to be a safer alternative due to its high antibacterial activity and nontoxicity to humans. The fact that different nisin derivatives can now be generated to target specific pathogenic organisms makes it even more attractive as a natural and potent antimicrobial for clinical and food use.”

“It may also be possible to reduce the levels of other preservatives such as salt, sugar and certain chemicals often used in high concentrations to inhibit bacterial growth.”