Microbial infections are among the worst human diseases and cause millions of deaths per year over the world. Antibiotics are used to treat infections and have saved more lives than any other drug in human history. However, due to extended use, many strains are becoming refractive to common antibiotics. In this light, new promising compounds, like antimicrobial proteins and peptides (AMPs) are being investigated. Some AMPs also show agglutinating activity; this is the ability to clump bacteria after treatment. This feature is particularly appealing because agglutinating peptides could be used to keep bacteria to the infection focus, helping microbe clearance by host immune cells.
This paper proposes a novel mechanism to explain agglutinating activity at a molecular level using Eosinophil Cationic Protein. The agglutinating mechanism is driven by the protein amyloid-like aggregation at the bacteria cell surface. Accordingly, elimination of the amyloid behavior abolishes both the agglutinating and the antimicrobial activities. This is a new concept of how nature could exploit amyloid-like aggregates to fight bacterial infections. These results could also add new insights in understanding the relation between infection and inflammation with dementia and amyloid-related diseases like Alzheimer.