To understand the roles of human gut bacteria in the occurrence of neuropsychiatric disorders, we isolated inflammatory Escherichia coli K1 and anti-inflammatory Lactobacillus mucosae from healthy human feces and examined their effects on the occurrence of altered microbiota, cognitive decline, and depression in mice. Oral gavage of Escherichia coli K1 caused colitis, cognitive decline, and depression in mice in the elevated plus maze, tail suspension, and forced swimming tasks. However, NK41 treatment reduced K1-induced cognitive decline and anxiety/depression. Furthermore, NK41 treatment increased K1-suppressed brain-derived neurotrophic factor (BDNF) expression and BDNF⁺/NeuN⁺ cell population and suppressed K1-induced NF-κB activation and LPS⁺/Iba1⁺ and NF-κB⁺/Iba1⁺ (microglial) cell populations in the hippocampus. NK41 treatment also suppressed K1-induced TNF-α and LPS levels in the blood and TNF-α expression, myeloperoxidase activity, NF-κB⁺/CD11c⁺ and CD11b⁺/CD11c⁺ cell populations in the colon. Furthermore, NK41 treatment decreased K1-induced colonic MUC2 expression, gut Proteobacteria population, and fecal LPS levels and modified the bacterial abundance related to polysaccharide breaking and biosynthesis. In conclusion, the overgrowth of inflammatory bacteria such as Escherichia coli in the gastrointestinal tract can cause neuropsychiatric disorders with gut microbiota alteration and the superiority of anti-inflammatory bacteria such as Lactobacillus mucosae can alleviate neuropsychiatric disorders with the attenuation of altered microbiota.

为了了解人类肠道细菌在神经精神疾病中的作用，我们分离了炎症 大肠杆菌 K1和消炎 粘膜乳杆菌从健康的人类粪便中提取，并检查它们对小鼠中微生物群改变，认知能力下降和抑郁症的发生的影响。口管大肠杆菌K1在高架迷宫，尾巴悬吊和强迫游泳中引起小鼠结肠炎，认知能力下降和抑郁。但是，NK41治疗可减少K1诱导的认知能力下降和焦虑/抑郁。此外，NK41治疗可增加K1抑制的脑源性神经营养因子（BDNF）的表达和BDNF ⁺ / NeuN ⁺细胞的数量，并抑制K1诱导的NF-κB活化和LPS ⁺ / Iba1 ⁺和NF-κB ⁺ / Iba1 ⁺（小胶质细胞） ）海马中的细胞群。NK41处理还抑制了K1诱导的血液中TNF-α和LPS水平以及TNF-α表达，髓过氧化物酶活性，NF-κB ⁺ / CD11c ⁺和CD11b⁺ / CD11c ⁺结肠中的细胞群。此外，NK41处理降低了K1诱导的结肠MUC2表达，肠道菌群和粪便LPS水平，并改变了与多糖破坏和生物合成有关的细菌丰度。总之，炎性细菌如大肠杆菌 在胃肠道中可引起神经精神疾病，肠道菌群改变和抗炎细菌的优越性，例如 粘膜乳杆菌 可以通过改变微生物群而减轻神经精神疾病。