Scientific article: Killing multi-resistant bugs with ionic liquids

Bacterial infections contribute to the death of 200’000 people per year in the US and Europe alone, and they are a much worse scourge in developing countries. Multi-drug resistant bacteria are already a serious threat to human health, with far too few antibiotics in the pipeline to counter the rapidly increasing antibiotics resistance. We found that a novel class of physically acting antimicrobials, ionic liquids, can efficiently kill one of the worst multi-resistant bacterial species.

Pseudomonas aeruginosa is a multi-drug resistant (MDR) pathogen. WHO classifies it as one of the most life-threatening pathogens causing healthcare-associated infections. Some of its clinical isolates show high persistence to many antibiotics that are recommended by the European Committee on Antimicrobial Susceptibility Testing. Thus, there is a need for new types of antibiotics to fight the increasing threat of MDR P. aeruginosa.

Ionic liquids (IL) are one such promising class of novel antibiotics. They are amphiphilic molecules believed to both disrupt bacterial membranes and, if correctly designed, interfere with bacterial metabolism. Hence, it would be difficult for bacteria to develop resistance against them.

We selected four strains of P. aeruginosa and studied the growth inhibition and other effects of 12 different ILs. The ILs consisted of either 4,4-didecylmorpholinium [Dec2Mor]þor 4-decyl-4-ethylmorpholinium [DecEtMor]þcations combined with different anions. We found that the ILs with 4,4-didecylmorpholinium [Dec2Mor]þcations most effectively inhibited bacterial growth as well as reduced strain fitness and virulence factor production. Our results indicate a new way to treat P. aeruginosa infections.

These results were published in the journal Research in Microbiology by Dr. Clapa et al. as part of an ongoing collaboration between the Institute of Biologically inspired materials and the Poznan University of Life Sciences to find novel ways to combat pathogen biofilms.