Peptide-containing nanofibers keep bacterial infections at bay

Researchers have developed a new infection-blocking material made of peptide-containing nanofibers that works against antibiotic-resistant bacteria and could one day be incorporated into wound dressings (ACS Infect. Dis. 2017, DOI: 10.1021/acsinfec​dis.6b00173). The approach targets bacterial quorum sensing—a mode of chemical communication used by bacteria to detect other bacteria. When they sense that enough of their kind are present, they can mount an infectious attack. Chemist Helen E. Blackwell of the University of Wisconsin, Madison, has developed peptides to block this quorum-sensing pathway, thereby preventing cells from attacking their host. Together with David M. Lynn and other Wisconsin colleagues, Blackwell electrospun one of these peptides into poly(lactide-co-glycolide) nanofibers. The researchers tested nanofiber mats against normal and deadly antibiotic-resistant strains of Staphylococcus aureus. By using a strain of S. aureus engineered to carry fluorescent reporter genes, the scientists found that the fibers with quorum-sensing inhibitors were able to block the bacteriafrom successful quorum sensing for up to two weeks. Moreover, when cultured in petri dishes with red blood cells, the treated bacterial cells did not rupture the blood cells, whereas untreated cells did. The presence of ruptured cells indicates that bacteria are using quorum sensing to coordinate an infection.