Title Interaction of Acinetobacter baumannii 19606 and 1656-2 with Acanthamoeba castellanii
Author Migma Dorji Tamang1, Shukho Kim1, Sung-Min Kim1, Hyun-Hee Kong2, and Jungmin Kim2*
Address 1Department of Microbiology , 2Department of Parasitology, Kyungpook National University School of Medicine, Daegu 700-422, Republic of Korea
Bibliography Journal of Microbiology, 49(5),841-846, 2011,
DOI
Key Words invasion assay, cytotoxicity, protozoa-bacteria interaction, host model
Abstract Acinetobacter baumannii is virtually avirulent for healthy people but maintains a high virulence among critically ill patients or immuno-compromised individuals. The ability of A. baumannii to adhere to cells and persist on surfaces as biofilms could be central to its pathogenicity. In the present study, we compared the virulence of the A. baumannii 1656-2 clinical strain, which is able to form a thick biofilm, with the virulence of the A. baumannii type strain (ATCC 19606T). Acanthamoeba castellanii, a single-celled organism, was used as the host model system to study the virulence of A. baumannii. Compared to A. baumannii ATCC 19606T, A. baumannii 1656-2 exhibited a higher ability to adhere and invade A. castellanii cells and had a higher killing rate of A. castellanii cells. Furthermore, co-incubation of the amoeba cells and the cell-free supernatant of A. baumannii resulted in the cell death of the amoebae. Heat inactivation or proteinase K treatment of the supernatant did not eliminate its cytotoxicity, suggesting heat stable non-protein factors are responsible for its cytotoxicity to A. castellanii cells. In conclusion, this study for the first time has revealed the capacity of the A. baumannii strain and/or its metabolic products to induce cytotoxicity in A. castellanii cells.