Undernutrition in children commonly disrupts the structure and function of the small intestinal microbial community, leading to enteropathies, compromised metabolic health, and impaired growth and development. The mechanisms by which diet and microbes mediate the balance between commensal and pathogenic intestinal flora remain elusive. In a murine model of undernutrition, we investigated the direct interactions Giardia lamblia, a prevalent small intestinal pathogen, on indigenous microbiota and specifically on Lactobacillus strains known for their mucosal and growth homeostatic properties. Our research reveals that Giardia colonization shifts the balance of lactic acid bacteria, causing a relative decrease in Lactobacillus spp. and an increase in Bifidobacterium spp. This alteration corresponds with a decrease in multiple indicators of mucosal and nutritional homeostasis. Additionally, protein-deficient conditions coupled with Giardia infection exacerbate the rise of primary bile acids and susceptibility to bile acid-induced intestinal barrier damage. In epithelial cell monolayers, Lactobacillus spp. mitigated bile acid-induced permeability, showing strain-dependent protective effects. In vivo, L. plantarum, either alone or within a Lactobacillus spp consortium, facilitated growth in protein-deficient mice, an effect attenuated by Giardia, despite not inhibiting Lactobacillus colonization. These results highlight Giardia's potential role as a disruptor of probiotic functional activity, underscoring the imperative for further research into the complex interactions between parasites and bacteria under conditions of nutritional deficiency.

中文翻译：

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贾第鞭毛虫在蛋白质缺乏期间拮抗本地和治疗性肠道细菌的有益功能。


儿童营养不良通常会破坏小肠微生物群落的结构和功能，导致肠病、代谢健康受损以及生长发育受损。饮食和微生物介导共生菌群和致病性肠道菌群之间平衡的机制仍然难以捉摸。在营养不良的小鼠模型中，我们研究了蓝氏贾第鞭毛虫（一种普遍的小肠病原体）与本地微生物群的直接相互作用，特别是与以其粘膜和生长稳态特性而闻名的乳酸菌菌株的直接相互作用。我们的研究表明，贾第鞭毛虫定植改变了乳酸菌的平衡，导致乳酸菌属相对减少，双歧杆菌属增加。这种改变对应于粘膜和营养稳态的多个指标的减少。此外，蛋白质缺乏症加上贾第鞭毛虫感染加剧了初级胆汁酸的增加和对胆汁酸诱导的肠道屏障损伤的易感性。在上皮细胞单层中，乳酸菌属减轻了胆汁酸诱导的通透性，显示出菌株依赖性保护作用。在体内，L. plantarum，无论是单独还是在乳酸菌 spp 财团中，都促进了蛋白质缺陷小鼠的生长，尽管不抑制乳酸菌定植，但这种影响被贾第鞭毛虫减弱。这些结果突出了贾第鞭毛虫作为益生菌功能活性破坏者的潜在作用，强调了进一步研究营养缺乏条件下寄生虫和细菌之间复杂相互作用的必要性。