Novel Pathogenicity of Secretory Proteins from Acinetobacter Radioresistens in Experimental Models

Background: Acinetobacter species are environmental microorganisms that inhabit the skin and can become opportunistic pathogens in immunocompromised hosts. This study investigated the pathogenicity of proteins released extracellularly by Acinetobacter radioresistens (A. radioresistens), isolated from the small intestine of two patients with severe Kawasaki disease, in a mouse model. Methods: The sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of culture supernatants derived from Acinetobacter species showed large variations in protein compositions among species and strains. The biological effects of soluble proteins secreted by A. radioresistens were evaluated in mice by intraperitoneal injection of culture supernatants. Results: The administration of culture supernatant derived from A. radioresistens caused weight loss, electrolyte imbalance, and decreased aldosterone levels. The sustained infiltration of the inflammatory mononuclear cells was observed in the liver of mice 6 weeks after the last administration. Conclusions: A. radioresistens expressed virulence through its extracellular proteins, leading to acute adrenal gland insufficiency and chronic inflammation of the livers.