Poster Presentation Australian Society for Microbiology Annual Scientific Meeting 2019

Transcriptomic analysis of growth and host infection related genes for Legionella pneumophila isolated from Korea (#133)

Dalmuri Han 1 , Se Mi Jeon 1 , Sung Soon Kim 1 , Hae Kyung Lee 1
  1. Division of Bacterial Diseases Research, Center for Infectious Diseases Research, National Institute of Health, Korea Centers for Disease Control & Prevention, Cheongju, Republic of Korea

Legionella in waterborne environments is biofilm-forming, growing in an inhibited state, or growing and surviving in protozoa such as amoeba. It is necessary to sense environmental changes and response by controlling the expression of appropriate genes for successful infection in human. To study the pathogenicity in Legionella pneumophila isolated from Korea, we analyzed the expression profiles of transcriptome in the clinical isolate (KP14), environmental isolate (KJ08261), and reference strain (Philadelphia-1). In order to investigate the changes of growth phase dependent gene expression in L. pneumophila, we measured the growth rate and compared the differential expressed genes at early exponential phase and early stationary phase. In addition, to study whether the gene necessary for efficient host infection was pre-expressed when Legionella as exposed to the host environment, it was compared with BYE broth and DMEM media. Interestingly, the results showed that the profiles of the genes that changed when exposed to DMEM media, were very similar as Legionella reached the early stationary phase. Expression of genes for type II and IV secretion system, flagella, and alpha-amylase related genes were up-regulated and genes related to host infection were also increased. However, down-regulation genes for expression of RNA-polymerase and ribosome machinery components are expected to result in a significant decrease in transcription and translation, which may be related to a negative effect in growth rate. Our results will be used for further studies on pathogenicity of Korea isolates. This research was supported by a fund (2018-NI001) by Research of Korea Centers for Disease Control and Prevention.