New, more effective nisin antibiotics combat superbugs and food diseases

Mar 31, 2009

Researchers at University College Cork have used bioengineering to produce a new generation of natural antibiotics that target harmful micro-organisms such as MRSA and the food-borne pathogen, Listeria monocytogenes.

Today (Tuesday 31 March), at the Society for General meeting in Harrogate, Dr Field and colleagues explained how by altering different in nisin, an antimicrobial protein produced naturally by a bacterium called Lactococcus lactis, they had created a family of variants, each slightly different from the naturally occurring protein. These bioengineered nisin variants possessed greater activities than the parent molecule against a range of important clinical pathogens including MRSA, VRE (Vancomycin resistant Enterococci) and the food-borne pathogen Listeria monocytogenes. Nisin is US FDA (United States Food and Drug Administration) approved and is used 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.

has become a serious public threat and these enhanced nisin variants could become acceptable alternatives to the range of antimicrobials currently available. For instance, nisin is presently included as the active ingredient in a number of commercial products that are used in the treatment of bovine mastitis. From a veterinary perspective, enhanced nisin derivatives with greater specific activities against the bacteria associated with bovine mastitis are a welcome addition to the current antibiotics used to treat this debilitating and economically costly disease.

Using enhanced nisin variants against food-borne pathogens such as Listeria is particularly significant as this bacterium is among the most naturally nisin resistant pathogens. Listeria monocytogenes usually causes illness in vulnerable groups such as pregnant women, babies, the elderly and people with reduced immunity. Among these groups, the illness is often severe and life threatening. The bacterium has been found in a variety of raw foods, such as uncooked meats and vegetables, as well as in processed foods that become contaminated after processing such as soft cheeses and hot dogs. The economic loss due to recalls of meat and poultry products contaminated with this pathogen is estimated at $1.2-$2.4 billion dollars per year in the United States. In addition, food surveys in the U.S. have estimated the prevalence of L. monocytogenes at 1.6-7.6% in meat, fish, and vegetable products, most of which were RTE (Ready to Eat) foods. In light of this, improved versions of nisin that specifically target Listeria are desirable, and could be a more preferable option than the current form of nisin for some food biopreservation applications.

"For example," said Dr Field, "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, ultimately leading to not only safe but healthier foods."

Source: Society for General Microbiology

Explore further: Researchers successfully clone adult human stem cells

add to favorites email to friend print save as pdf

Related Stories

Recommended for you

Researchers successfully clone adult human stem cells

8 hours ago

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

Researchers develop new model of cellular movement

11 hours ago

(Phys.org) —Cell movement plays an important role in a host of biological functions from embryonic development to repairing wounded tissue. It also enables cancer cells to break free from their sites of ...

For resetting circadian rhythms, neural cooperation is key

Apr 17, 2014

Fruit flies are pretty predictable when it comes to scheduling their days, with peaks of activity at dawn and dusk and rest times in between. Now, researchers reporting in the Cell Press journal Cell Reports on April 17th h ...

User comments : 0

More news stories

Researchers successfully clone adult human stem cells

(Phys.org) —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

Plants with dormant seeds give rise to more species

Seeds that sprout as soon as they're planted may be good news for a garden. But wild plants need to be more careful. In the wild, a plant whose seeds sprouted at the first warm spell or rainy day would risk disaster. More ...

Researchers develop new model of cellular movement

(Phys.org) —Cell movement plays an important role in a host of biological functions from embryonic development to repairing wounded tissue. It also enables cancer cells to break free from their sites of ...

Male monkey filmed caring for dying mate (w/ Video)

(Phys.org) —The incident was captured by Dr Bruna Bezerra and colleagues in the Atlantic Forest in the Northeast of Brazil.  Dr Bezerra is a Research Associate at the University of Bristol and a Professor ...

Treating depression in Parkinson's patients

A group of scientists from the University of Kentucky College of Medicine and the Sanders-Brown Center on Aging has found interesting new information in a study on depression and neuropsychological function in Parkinson's ...