Chryseobacterium indologenes and Chryseobacterium gleum interact and multiply intracellularly in Acanthamoeba castellanii

Wei-Gene Lim; Tommy Tong; Jactty Chew

doi:10.1016/j.exppara.2020.107862

Chryseobacterium indologenes and Chryseobacterium gleum interact and multiply intracellularly in Acanthamoeba castellanii

Exp Parasitol. 2020 Feb 19:211:107862. doi: 10.1016/j.exppara.2020.107862. Online ahead of print.

Authors

Wei-Gene Lim¹, Tommy Tong¹, Jactty Chew²

Affiliations

¹ Department of Biological Sciences, Sunway University, Bandar Sunway, Selangor, 47500, Malaysia.
² Department of Biological Sciences, Sunway University, Bandar Sunway, Selangor, 47500, Malaysia. Electronic address: jacttyc@sunway.edu.my.

PMID: 32087220
DOI: 10.1016/j.exppara.2020.107862

Abstract

Chryseobacterium indologenes and Chryseobacterium gleum are Gram negative environmental bacteria that have been frequently reported to implicate in fatal nosocomial infections, such as bacteraemia and ventilator-associated pneumonia in immunocompromised individuals in the past decades. The interaction between Chryseobacterium spp. and Acanthamoeba castellanii, a free-living amoeba ubiquitous in the environment, has not been explored previously. In this study, C. indologenes and C. gleum were co-cultured with A. castellanii trophozoites and their interactions were evaluated. Our results showed that when co-cultured with A. castellanii, bacterial numbers of C. indologenes and C. gleum increased significantly (p < 0.05), indicating growth-supporting role of A. castellanii. Specifically, our findings showed that C. indologenes and C. gleum were able to associate, invade and/or taken up by A. castellani trophozoites, and multiply intracellularly at similar rates (p > 0.05). Interestingly, the two Chryseobacterium spp. associated, invaded and/or taken up by A. castellanii at significantly higher rates than Escherichia coli K1, a neuropathogenic bacterial strain known to interact and replicate intracellularly in A. castellanii (p < 0.05). However, the ability of both Chryseobacterium spp. to multiply in A. castellanii was significantly weaker than E. coli K1 (p < 0.001). This is the first time that Chryseobacterium spp. and A. castellanii were shown to interact with each other. The ability to survive intracellularly in A. castellanii may confer protection to C. indologenes and C. gleum and assist in the survival and transmission of Chryseobacterium spp. to susceptible hosts within a hospital setting. Future studies will determine the ability of C. indologenes and C. gleum survival in A. castellanii cysts and the possible molecular mechanisms involved in such interactions.

Keywords: Acanthamoeba castellanii; Chryseobacterium gleum; Chryseobacterium indologenes; Enodocytobionts; Interactions; Intracellular survival.