Akya Alisha, Pointon Andrew, Thomas Connor
University of Adelaide, School of Molecular and Biomedical Science, Adelaide, SA, Australia.
FEMS Microbiol Ecol. 2009 Oct;70(1):20-9. doi: 10.1111/j.1574-6941.2009.00736.x. Epub 2009 Jul 1.
Listeria monocytogenes is a human pathogen, ubiquitous in the environment, and can grow and survive under a wide range of environmental conditions. It contaminates foods via raw materials or food-processing environments. However, the current knowledge of its ecology and, in particular, the mode of environmental survival and transmission of this intracellular pathogen remains limited. Research has shown that several intracellular pathogens are able to survive or replicate within free-living amoebae. To examine the viability of L. monocytogenes in interaction with Acanthamoeba spp., bacteria were co-cultured with three freshly isolated amoebae, namely Acanthamoeba polyphaga, Acanthamoeba castellanii and Acanthamoeba lenticulata. The survival of bacteria and amoebae was determined using culture techniques and microscopy. Under the experimental conditions used, all amoebae were able to eliminate bacteria irrespective of the hly gene. Bacteria did not survive or replicate within amoeba cells. However, extra-amoebic bacteria grew saprophytically on materials released from amoebae, which may play an important role in the survival of bacteria under extreme environmental conditions.
单核细胞增生李斯特菌是一种人类病原体，在环境中广泛存在，能够在多种环境条件下生长和存活。它通过原材料或食品加工环境污染食品。然而，目前对其生态学的了解，特别是这种细胞内病原体在环境中的存活和传播方式仍然有限。研究表明，几种细胞内病原体能够在自由生活的变形虫内生存或复制。为了检测单核细胞增生李斯特菌与棘阿米巴属相互作用时的生存能力，将细菌与三种新分离的变形虫共同培养，即多食棘阿米巴、卡氏棘阿米巴和透镜状棘阿米巴。使用培养技术和显微镜检查细菌和变形虫的存活情况。在所使用的实验条件下，所有变形虫都能够清除细菌，无论其hly基因如何。细菌在变形虫细胞内无法存活或复制。然而，细胞外的细菌在变形虫释放的物质上腐生生长，这可能在极端环境条件下细菌的存活中起重要作用。
