Bdellovibrio and the intestinal flora of vertebrates.

Bdellovibrio strain MS7 force-fed to fish and frogs via an intragastric tube did not become an integral component of the intestinal microflora. Strain MS7 fed to mice in drinking water was not recovered from the intestinal tract of mice. However, in vitro, the organism multiplied in intestinal contents of frogs and mice. Bdellovibrio inoculated into rabbit ileal loops was greatly reduced in number within 24 h. It was concluded that strains MS7 could be considered nonpathogenic to animals, at least when introduced into the digestive tract, and that it is not feasible at the present time to lyse pathogenic, gram-negative bacteria in the alimentary tract with Bdellovibrio.     

Periplasmic enzymes in Bdellovibrio bacteriovorus and Bdellovibrio stolpii.

When cells of either Bdellovibrio bacteriovorus 109J or Bdellovibrio stolpii UKi2 were subjected to osmotic shock by treatment with sucrose-EDTA and MgCl2 solutions, only trace amounts of proteins or enzyme activities were released into the shock fluid. In contrast, when nongrowing cells were converted to motile, osmotically stable, peptidoglycan-free spheroplasts by penicillin treatment, numerous proteins were released into the suspending fluid. For both species, this suspending fluid contained substantial levels of 5'-nucleotidase, purine phosphorylase, and deoxyribose-phosphate aldolase. Penicillin treatment also released aminoendopeptidase N from B. bacteriovorus, but not from B. stolpii. Penicillin treatment did not cause release of cytoplasmic enzymes such as malate dehydrogenase. The data indicated that bdellovibrios possess periplasmic enzymes or peripheral enzymes associated with the cell wall complex. During intraperiplasmic bdellovibrio growth, periplasmic and cytoplasmic enzymes of the Escherichia coli substrate cell were not released upon formation of the spherical bdelloplast during bdellovibrio penetration. Most of the E. coli enzymes were retained within the bdelloplast until later in the growth cycle, when they became inactivated or released into the suspending buffer or both.     

Composition and ecology of the human intestinal flora

Longitudinal quantitative cultures of fecal flora of 20 newborns, 4 older babies and 10 healthy adults were carried out to study the composition and development of the intestinal flora. In all newborns the same sequence of colonization was observed. The numbers of aerobic and anaerobic bacteria fluctuated and reached finally numbers of 10¹⁰/g wet weight. In adults the flora was in balance with 10⁵–10⁷ aerobic and 10¹⁰–10¹¹ anaerobic bacteria/g wet weight. Interaction experiments in vitro showed growth inhibition of Bacteroides fragilis by all intestinal species isolated. Bifidobacteria were not inhibited. The assumption was made that this type of interaction could be one of the mechanisms involved in the intestinal micro-ecology. Three of the Bacteroides fragilis strains tested were able to grow on natural intestinal substrates as gastric mucin, glycogen and a variety of plant polysaccharides. Acetic, lactic, propionic and succinic acids were detected as fermentation products.     

Effect of intestinal flora on megaenteron of mice.

CF#1 germfree (GF) and conventional (CV) mice as well as offspring of conventionalized GF (GF-CV) mice were orally inoculated with Escherichia coli 0115a, c: K(B), a causative agent of megaenteron in mice. Although CV and GF mice showed no clinical signs and survived, all of the GF-CV mice died with diarrhea by day 14 after inoculation. Thickened wall of the large intestine, microscopically showing proliferation of crypt type cells, was seen in GF and GF-CV mice but not in CV mice. In addition, in GF-CV mice, hemorrhage and severe erosion with marked inflammatory reactions were observed. While the inoculated E. coli could not colonize in CV mice, a level of 10⁸ cells/g feces was maintained in GF mice from day 1 after inoculation to the end of examination (on day 28) and in GF-CV mice from day 5 to the time of death. Newly prepared germfree (GF-CV-GF) mice obtained hysterectomy from GF-CV mice showed a low sensitivity as comparable to that in GF mice. On the other hand, ex-germfree mice produced by oral administration of feces of GF-CV mice showed severe infection as comparable to that seen in GF-CV mice. These results suggest that the intestinal flora may play roles both on protecting from the infection of pathogenic E. coli and on enhancing the infection.     

慢性阻塞性肺疾病急性发作期患者肠道菌群特征及血清同型半胱氨酸、白介素-6对其肠道菌群失调的预测效能

分析慢性阻塞性肺疾病急性发作期（AECOPD）患者肠道菌群特征及血清同型半胱氨酸（Hcy）、白介素-6（IL-6）对患者肠道菌群失调的预测效能。

将2020年1月至2022年1月我院收治的96例AECOPD患者纳入研究组,另选同期健康体检者88例作为对照组。所有纳入对象入院后均采集血液、粪便样本检测血清Hcy、IL-6水平及肠道菌群。比较两组对象血清Hcy、IL-6水平及肠道菌群数量差异。采用受试者工作特性曲线（ROC）分析血清Hcy、IL-6对AECOPD患者肠道菌群失调的预测效能,同时采用单因素、多因素Logistic回归分析探讨影响AECOPD患者肠道菌群失调的相关因素。

研究组患者肠道双歧杆菌、乳杆菌数量均显著低于对照组（t = −10.167、−4.045,均P＜0.001）,大肠埃希菌、肠球菌数量均显著高于对照组（t = 8.493、8.440,均P＜0.001）。96例AECOPD患者肠道菌群失调发生率为36.45%（35/96）。与对照组血清Hcy[（10.76±3.23）μmol/L]、IL-6[（0.86±0.35）mg/L]水平相比较,肠道菌群失调组AECOPD患者血清Hcy[（38.65±5.41）μmol/L]、IL-6[（132.55±25.62）mg/L]水平和肠道菌群正常组患者血清Hcy[（20.22±4.18）μmol/L]、IL-6[（40.58±6.69）mg/L]水平均显著升高（t = 28.543、30.408、14.865、46.327,均P＜0.001）,且肠道菌群失调组AECOPD患者血清Hcy、IL-6水平均显著高于肠道菌群正常组（t = 18.641、25.664,均P＜0.001）。ROC曲线显示,血清Hcy预测AECOPD患者肠道菌群失调的曲线下面积为0.771,截断值为29.50 μmol/L,灵敏度、特异度分别为92.62%、58.62%;IL-6预测AECOPD患者肠道菌群失调的曲线下面积为0.752,截断值为88.69 mg/L,灵敏度、特异度分别为92.62%、65.34%;血清Hcy联合IL-6预测AECOPD患者肠道菌群失调的曲线下面积为0.901,灵敏度、特异度分别为86.04%、87.65%。多因素Logistic回归分析显示,血清Hcy[OR（95% CI） = 3.904（2.049～7.440）]、IL-6[OR（95% CI） = 3.414（1.926～6.052）]及急性加重次数≥2次/年[OR（95% CI） = 3.404（1.936～5.986）]均为影响AECOPD患者肠道菌群失调的相关因素。

AECOPD患者存在肠道菌群失调,且主要表现为双歧杆菌、乳杆菌减少及大肠埃希菌、肠球菌增多,其发生与血清Hcy、IL-6水平密切相关,血清Hcy、IL-6水平的升高可作为预测AECOPD患者肠道菌群失调的有效指标。

     

肠道菌群与疾病发生及中草药调节和治疗作用的研究概述

肠道正常菌群及微生态稳定对人体极具重要性,中草药对肠道菌群具有调节作用.本文综述了人体的肠道正常菌群与疾病产生和发展的关系,结合中草药对肠道菌群调节作用的研究,探讨中药调节肠道菌群与其发挥疾病防治效果之间的相关性,以期为中草药的临床应用及药理学研究提供一定的参考依据.     

Effect of sulphasalazine on the human intestinal flora

Sulphasalazine is commonly used to treat patients with ulcerative colitis but the mode of action is still unexplained. To investigate a possible antibacterial effect of sulphasalazine, the faecal flora composition was studied in patients with ulcerative colitis and in mice harbouring a human intestinal flora. Patients on sulphasalazine were found to have an intestinal flora that was completely resistant to sulphapyri-dine. Oral administration of sulphasalazine did not influence the composition of the human flora in mice.     

肠道菌群与婴幼儿体重的研究进展

肥胖已成为全球急需解决的公共健康问题之一。新生儿体重过重伴随着易患各种感染性疾病和造成孕妇分娩困难等问题。另外,婴幼儿超重在儿童期和成年期更容易发生超重和肥胖问题。近年来,大量研究对肠道菌群与肥胖之间的调节和作用关系,以及影响肠道菌群组成的因素进行了深入的探索。本文主要从我国新生儿肥胖现状及其危害,肠道菌群与肥胖的关系,婴幼儿肥胖与影响肠道菌群组成的饮食、抗生素等因素之间的关系等多个方面综述肠道菌群与体重的最新进展,为预防婴幼儿肥胖提供有效依据。     

Composition of the enterococcal and streptococcal intestinal flora of poultry

Identification to species level showed that Enterococcus faecalis and Ent. faecium largely dominated the enterococcal and streptococcal gut flora of 1-d-old chicks. Enterococcus faecalis was rare in 3- to 5-week-old broilers. Two species, Ent. faecium and Streptococcus alactolyticus , were isolated from nearly all broilers examined. Enterococcus hirae and Ent. durans were found in the small intestines of this category of poultry.
In layers and parent stock of over 12 weeks of age, Ent. cecorum dominated with Strep. alactolyticus ranking next. Other species were isolated irregularly. Enterococcus avium and Ent. gallinarum , originally described from chickens, were rarely found. These species did not appear to belong to the normal intestinal flora of poultry.     

Composition of the enterococcal and streptococcal intestinal flora of poultry

Identification to species level showed that Enterococcus faecalis and Ent. faecium largely dominated the enterococcal and streptococcal gut flora of 1-d-old chicks. Enterococcus faecalis was rare in 3- to 5-week-old broilers. Two species, Ent. faecium and Streptococcus alactolyticus, were isolated from nearly all broilers examined. Enterococcus hirae and Ent. durans were found in the small intestines of this category of poultry. In layers and parent stock of over 12 weeks of age, Ent. cecorum dominated with Strep. alactolyticus ranking next. Other species were isolated irregularly. Enterococcus avium and Ent. gallinarum, originally described from chickens, were rarely found. These species did not appear to belong to the normal intestinal flora of poultry.     

肠道菌群与免疫的相关性研究

由大量微生物构成的复杂微生物群落栖息在人体的肠道内,这些微生物统称作肠道菌群。肠道菌群在人体的消化吸收、免疫、生物拮抗、抗肿瘤等各项生命活动中发挥着重要的作用。近年来的许多研究提示,肠道内复杂的微生物群落和人体的免疫系统间存在着极为密切的关系。免疫系统发挥正常的功能及建立免疫的稳态与肠道菌群的作用密不可分。研究表明肠道菌群能阻止致病微生物入侵从而影响肠道免疫系统,同时还能影响全身免疫系统,在人体的自身免疫性疾病中有较为重要的作用。     

肠道菌群与抗生素相关性腹泻的关系

肠道菌群作为分布在人体肠道内的微生物菌群,对发挥肠道正常生理功能起到了至关重要的作用。临床研究表明,大量使用广谱性抗菌药物会打破肠道菌群的平衡,导致抗生素相关性腹泻(Antibiotic-associated diarrhea,AAD)。然而,不同的肠道菌群与AAD的关系不尽相同。本文分别从致病菌导致AAD的机制、益生菌预防和治疗AAD的原理,以及条件致病菌与AAD的关系等方面进行综述,旨在为肠道菌群与AAD的研究提供理论依据,同时为临床上更精准地预防、诊断和治疗AAD提供参考。     

阿如拉7味散对肠道菌群失调小鼠免疫功能及肠道菌群多样性的影响

目的 研究阿如拉7味散对抗生素诱导肠道菌群失调小鼠的免疫功能和肠道菌群多样性的影响。 方法 选取50只清洁级昆明小鼠,分为正常对照组、自然恢复组、阳性对照组、阿如拉7味散低剂量组(0.5 g/mL)和阿如拉7味散高剂量组(1.0 g/mL)。将所有小鼠用头孢曲松钠和盐酸林可霉素混合药液灌胃制备肠道菌群失调模型,第8天起各组小鼠相应药物连续治疗7 d,实验结束时进行样品采集。采集血清和回肠组织,采用ELISA法检测血清中的IgG、IFNγ和TNFα含量以及回肠组织中的sIgA含量;采集盲肠内容物,采用高通量测序技术检测肠道菌群多样性;采集胸腺和脾脏,测定免疫器官指数。 结果 阿如拉7味散低、高剂量可显著提高抗生素诱导肠道菌群失调小鼠的脾脏指数(P0.05)和血清IgG含量(P>0.05)无显著影响。各用药组与自然恢复组相比,尤其阿如拉7味散低剂量组,小鼠肠道菌群丰富度和多样性明显升高。 结论 阿如拉7味散对抗生素诱导肠道菌群失调小鼠具有提高免疫器官指数、增强肠道免疫功能和改善肠道菌群的作用。