New weapon against resistant bacteria

ANTIMICROBIAL resistance is growing in many strains of pathogenic bacteria, but engineers in Singapore say they have developed a substance which can kill more than 99% of bacteria in just two minutes.

The researchers at the Institute of Bioengineering and Nanotechnology (IBN) at the Agency for Science, Technology and Research (A*STAR), led by IBN group leader Yugen Zhang, were seeking an alternative to triclosan. Triclosan is an antibacterial and antifungal compound widely used in consumer goods and household cleaning products. Its application is increasingly being restricted due to concerns about its effects on the environment, human health, and its contribution to antibiotic resistance in bacteria. Resistance to triclosan in some cases appears to give co-resistance to other antimicrobials, like antibiotics. The growth of drug-resistant bacteria is becoming a global health concern, so alternatives are needed.

The new substance consists of imidazolium oligomers linked in long chains. These chains can penetrate the cell wall of the bacteria and destroy them. In tests, the new substance killed 99.7% of Escherichia coli in less than 30 seconds. It eradicated 99.9% of the bacteria Staphylococcus aureus and Pseudomonas aeruginosa and the pathogenic yeast Candida albicans within two minutes.

“Our unique material can kill bacteria rapidly and inhibit the development of antibiotic-resistant bacteria. Computational chemistry studies supported our experimental findings that the chain-like compound works by attacking the cell membrane. This material is also safe for use because it carries a positive charge that targets the more negatively charged bacteria, without destroying red blood cells,” said Zhang.

The imidazolium chains are in the form of a white powder, which forms a gel when mixed with alcohol. The researchers say it could be easily incorporated in sprays and hand gels used for sterilisation in healthcare settings and in the home.

Small DOI: 10.1002/smll.201600006