Laboratory of Molecular and Cellular Parasitology, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, 117545, Singapore.
Institute of Biology and Natural Sciences Research Institute, College of Science, University of the Philippines, Diliman, Quezon City, 1101, Philippines.
Microbiome. 2019 Mar 11;7(1):30. doi: 10.1186/s40168-019-0644-3.
Blastocystis is a common gut eukaryote detected in humans and animals. It has been associated with gastrointestinal disease in the past although recent metagenomic studies also suggest that it is a member of normal microbiota. This study investigates interactions between pathogenic human isolates belonging to Blastocystis subtype 7 (ST7) and bacterial representatives of the gut microbiota.
Generally, Blastocystis ST7 exerts a positive effect on the viability of representative gut bacteria except on Bifidobacterium longum. Gene expression analysis and flow cytometry indicate that the bacterium may be undergoing oxidative stress in the presence of Blastocystis. In vitro assays demonstrate that Blastocystis-induced host responses are able to decrease Bifidobacterium counts. Mice infected with Blastocystis also reveal a decrease in beneficial bacteria Bifidobacterium and Lactobacillus.
This study shows that particular isolates of Blastocystis ST7 cause changes in microbiota populations and potentially lead to an imbalance of the gut microbiota. This study suggests that certain isolates of Blastocystis exert their pathogenic effects through disruption of the gut microbiota and provides a counterpoint to the increasing reports indicating the commensal nature of this ubiquitous parasite.
芽囊原虫是一种常见的肠道真核生物，在人类和动物中均有发现。过去曾有研究表明其与胃肠道疾病有关，但最近的宏基因组研究也表明它是正常肠道微生物群的一员。本研究调查了属于芽囊原虫 7 型（ST7）的致病性人分离株与肠道微生物群代表细菌之间的相互作用。
一般来说，芽囊原虫 ST7 对代表肠道细菌的存活有积极影响，除了长双歧杆菌。基因表达分析和流式细胞术表明，在存在芽囊原虫的情况下，细菌可能会经历氧化应激。体外试验表明，芽囊原虫诱导的宿主反应能够降低双歧杆菌的数量。感染芽囊原虫的小鼠也显示有益细菌双歧杆菌和乳酸杆菌数量减少。
本研究表明，特定的芽囊原虫 ST7 分离株会引起微生物群种群的变化，并可能导致肠道微生物群失衡。本研究表明，某些芽囊原虫通过破坏肠道微生物群发挥其致病性作用，并为越来越多表明这种普遍寄生虫共生性质的报告提供了一个对照。
