青年人肠道菌群分布及关键益生菌群落结构分析

以30例20～25岁中国青年人的肠道菌群为研究对象,采用纯培养方法和16S rDNA测序等分子生物学技术并结合代谢产物β_半乳糖苷酶和短链脂肪酸的测定,分析了此年龄段健康人群肠道菌群分布和益生菌群落结构。实验表明,高厌氧菌水平和高B/E值（175.66）反映出此年龄段人群良好的肠道环境;肠道关键益生菌群落结构分析表明,双歧杆菌由1～4种菌种组成,青春双歧杆菌(检出率93.3%,占总双歧杆菌数量百分比>85%)、长双歧杆菌(检出率86.7%,占总双歧杆菌数量百分比10%)为肠道优势双歧杆菌,其余菌种在不同人肠道中的差异数量只占不到5％,此年龄段青年人肠道具有呈现稳定的双歧杆菌群落结构,肠道双歧杆菌群落结构与膳食结构、生活环境等因素相关性不大,主要与人的生理年龄紧密相关;卷曲乳杆菌和唾液乳杆菌为青年人肠道优势乳杆菌(检出率分别为86.7%和93.3%,两者之和占总乳杆菌的数量百分比为60%～75%),但其余乳杆菌在不同人肠道中的之间的差异数量达到20%～30％,肠道乳杆菌群落结构与饮食结构、生活环境等因素紧密相关,不同个体具有各自独特的乳杆菌群落组成。     

双歧杆菌三联活菌散联合葡萄糖酸锌对 儿童厌食症患者的疗效及其肠道菌群的影响

目的探讨双歧杆菌三联活菌散联合葡萄糖酸锌对儿童厌食症患者的疗效及其肠道菌群的影响。方法选取儿科门诊就诊的儿童厌食症患者80例,随机分为观察组和对照组各40例。两组患儿均予以调整饮食习惯及健胃消食药治疗。对照组患儿加用葡萄糖酸锌口服液10 mL/次,1次/d,口服。观察组患儿在对照组基础上加用双歧杆菌三联活菌散1.0～2.0 g/次,3次/d,温开水冲服。两组患儿均连用8周。观察并比较两组患儿治疗前后微量元素(铁和锌)及肠道菌群(乳杆菌、双歧杆菌和肠杆菌)的变化,并评估其临床效果。结果治疗8周后,两组患儿血清铁和锌含量均不同程度上升(P0.05),且观察组上升幅度较对照组更显著(P0.05)。治疗后观察组患儿肠道乳杆菌和双歧杆菌数量明显上升,肠杆菌数量明显下降(P0.05),而对照组患儿治疗前后肠道菌群数量变化无统计学意义(P0.05)。治疗后观察组患儿肠道乳杆菌和双歧杆菌数量高于对照组,肠杆菌数量低于对照组(P0.05),同时观察组患儿临床总有效率(95.00%)高于对照组(80.00%)。结论双歧杆菌三联活菌散联合葡萄糖酸锌对儿童厌食症患者的疗效确切,能增进患儿食欲和食量,其机制可能与其能能调节肠道菌群紊乱,改善患儿肠道微生态环境,促进肠道对铁和锌等微量元素的吸收和利用密切相关。     

双歧杆菌、乳杆菌制剂在食品工业中的研究现状与展望

正常人体肠道中存在着大量微生物 ,这些菌群的平衡对人体健康发挥着重要的作用。肠道内正常菌群作为一个整体存在 ,相互依赖又相互制约。机体肠道内菌群失调则出现一系列的生理功能紊乱 ,临床表现为腹泻和感染等。而近年来 ,益生菌 (剂 ) (probiotics)作为一类对人体有益的细菌的总称 ,它对腹泻和感染等疾病的治疗和预防有特殊的功效 ,已成为微生物学的研究热点 ,并在保健食工业上得到广泛应用。双歧杆菌、乳杆菌是目前开发应用最热门的两种益生菌。双歧杆菌、乳杆菌是机体有益的与人类健康又密不可分的重要生理菌群 ,二者对人健康和营养有…     

三联疗法抗幽门螺杆菌感染对儿童肠道菌群状态的影响

目的　探讨抗幽门螺杆菌治疗对儿童肠道菌群状态的影响。方法　分别称取18例幽门螺杆菌感染儿童治疗前后新鲜粪便1.0 g,对肠道菌群中最有代表性的3种需氧菌(肠杆菌、肠球菌和酵母菌)和4种厌氧菌(双歧杆菌、乳杆菌、类杆菌和产气荚膜梭菌) ,分别进行需氧和厌氧培养,菌落计数,同时计算B/ E值来代表定植抗力。结果　抗Hp治疗后,双歧杆菌、乳杆菌和类杆菌较治疗前明显降低( P<0 .0 5 ) ,B/ E值明显下降( P<0 .0 1) ,肠杆菌数量明显增加( P<0 .0 5 ) ,酵母菌的检出率明显增加( P<0 .0 5 )。结论　三联疗法抗Hp治疗对儿童肠道菌群产生明显的影响,因此在治疗Hp感染时须考虑到大量抗生素治疗后可能对患儿产生的副作用及潜在的危险     

双歧杆菌的研究进展

双歧杆菌是人类最早发现的生理性细菌之一。双歧杆菌是能在健康人肠道内定植的益生菌 ,母乳喂养的婴儿肠道内该菌占总菌群的 92 %以上 ,现在已确认双歧杆菌是人体健康的重要标志之一 [1 ] 。双歧杆菌在健康成年人及长寿老人的胃肠道内是优势菌 ,当机体患病或衰老时肠道双歧杆菌较正常人少 [2 ] ,其数量随年龄变化呈动态变化趋势 ,并与许多生理、病理现象密切相关 ,因此引起了医学领域内专家们的广泛关注。国内针对双歧杆菌曾多次召开微生态学术讨论会 ,在国际上 ,1990年在日本举行国际双歧杆菌专题讨论会 ,对双歧杆菌的生理、生化、分类、作…     

双歧杆菌的临床应用现状

双歧杆菌(B ifidobacterium)是由法国学者TISSIER于1899年采用厌氧培养法首次从健康母乳哺养的婴幼儿的粪便中分离出来的一种专性厌氧菌。婴儿出生2~3 d后双歧杆菌开始增殖,5 d后达最高峰并占绝对优势,占肠道菌群的99%。随着人的年龄增长,双歧杆菌在肠道内逐渐减少,体弱多病老人的肠道内该菌几乎消失,而健康人仍能保持一定的水平。现已认识到,双歧杆菌是人体重要的益生菌,是定植于健康人肠道内且数量占优势的一种细菌,终生存在于人体并与健康息息相关。双歧杆菌在肠道内参与了宿主的消化、营养、代谢、免疫、抗感染等生理过程,是人体健…     

酪酸梭菌--婴儿型双歧杆菌二联活菌制剂对人体肠道菌群的调节试验

目的　观察酪酸梭菌——婴儿型双歧杆菌二联活菌制剂对受试人群肠道菌群的影响。方法　检测受试者服用前后的肠道菌群并计数。结果　肠杆菌、肠球菌、拟杆菌的数量无明显变化 ,双歧杆菌、乳杆菌的数量明显增加 ,差异有非常显著性 (P<0 .0 1) ,结论　酪酸梭菌——婴儿型双歧杆菌二联活菌制剂具有一定的调节人体肠道菌群、增殖双歧杆菌和乳杆菌的作用。     

酪酸梭菌-双歧杆菌二联活菌制剂对慢性腹泻患者肠道菌群的影响

给慢性腹泻病人口服酪酸梭菌-双歧杆菌二联活菌制剂,然后检测患者服药前后的肠道菌群变化.患者服用药品后,葡萄球菌、酵母菌、消化球菌、真杆菌和小梭菌的数量无明显变化,肠杆菌、肠球菌的数量明显减少,拟杆菌、双歧杆菌、乳杆菌的数量明显增加,其中肠球菌、肠杆菌、拟杆菌和双歧杆菌的变化有显著性(P﹤0.05),提示酪酸梭菌-双歧杆菌二联活菌制剂对慢性腹泻病人的肠道菌群具有明显的影响、具有增殖拟杆菌、双歧杆菌和乳杆菌的作用.     

双歧杆菌寡核苷酸探针的制备和应用

在人类肠道微生态中 ,双歧杆菌是仅次于类杆菌和优杆菌的第三大菌属。双歧杆菌可能占全部可培养肠道菌群总数的 2 5 % ,所以是肠道微生态的重要组成部分 [1 ]。由于双歧杆菌能提高肠道微生态的定植抗力 ,有效拮抗致病菌的侵入 ,并被认为是基本不致病的微生物 ,所以已成为应用十分广泛的益生菌 [2 ]。成人最常见的分离菌为青春双歧、长双歧、短双歧杆菌等 ,婴儿双歧常见于婴儿。传统的鉴定以形态学和表型 (如胞内和胞外碳水化合物酶的酵解试验 )作为基础 ,不仅耗费大量时间精力 ,而且由于双歧杆菌是专性厌氧菌 ,一般不通过酵解途径获得能量 ,…     

重症肺炎新生儿肠道菌群特征和应激反应及益生菌干预的效果CSCD

目的研究重症肺炎新生儿肠道菌群特征、应激反应及益生菌干预的效果,为此类患儿的治疗提供参考。方法选取2019年1月至2020年3月我院收治的105例重症肺炎新生儿作为试验组,并选取我院产科48例健康新生儿作为对照组。采用随机数字表法将试验组分为益生菌组(n=53)和常规组(n=52),常规组给予新生儿重症肺炎常规治疗,益生菌组在常规组基础上联合运用益生菌治疗。对比试验组和对照组患儿肠道菌群特征,同时对比益生菌组和常规组患儿治疗前后肠道菌群特征和应激反应指标水平。结果相比于对照组,试验组患儿肠道乳杆菌(t=15.454,P<0.001)、肠球菌(t=23.191,P<0.001)、大肠埃希菌(t=25.274,P<0.001)数量显著升高,双歧杆菌数量显著降低(t=46.012,P<0.001)。治疗后,两组患儿肠道乳杆菌、肠球菌、大肠埃希菌数量均降低,双歧杆菌数量升高,且相比于常规组,益生菌组患儿肠道乳杆菌(t=3.617,P<0.001)、肠球菌(t=7.826,P<0.001)、大肠埃希菌数量显著降低(t=5.799,P<0.001),双歧杆菌数量显著升高(t=12.750,P<0.001)。治疗后,两组患儿总抗氧化能力(T-AOC)、超氧化物歧化酶(SOD)水平均升高,丙二醛(MDA)水平降低;且相比于常规组,益生菌组T-AOC(t=18.302,P<0.001)、SOD(t=8.639,P<0.001)水平显著升高,MDA水平显著降低(t=22.816,P<0.001)。结论重症肺炎新生儿肠道菌群主要以乳杆菌、肠杆菌、大肠埃希菌数量升高,双歧杆菌数量降低为特征。益生菌治疗能有效恢复患儿肠道菌群稳定,改善患儿应激反应。     

Development and assessment of a real-time pcr assay for rapid and sensitive detection of a novel thermotolerant bacterium, Lactobacillus thermotolerans, in chicken feces

A new real-time PCR assay was successfully developed using a TaqMan fluorescence probe for specific detection and enumeration of a novel bacterium, Lactobacillus thermotolerans, in chicken feces. The specific primers and probe were designed based on the L. thermotolerans 16S rRNA gene sequences, and these sequences were compared to those of all available 16S rRNA genes in the GenBank database. The assay, targeting 16S rRNA gene, was evaluated using DNA from a pure culture of L. thermotolerans, DNA from the closely related bacteria Lactobacillus mucosae DSM 13345(T) and Lactobacillus fermentum JCM 1173(T), and DNA from other lactic acid bacteria in quantitative experiments. Serial dilutions of L. thermotolerans DNA were used as external standards for calibration. The minimum detection limit of this technique was 1.84 x 10(3) cells/ml of an L. thermotolerans pure culture. The assay was then applied to chicken feces in two different trials. In the first trial, the cell population was 10(4) cells/g feces on day 4 and 10(5) cells/g feces on days 11 to 18. However, cell populations of 10(6) to 10(7) cells/g feces were detected in the second trial. The total bacterial count, measured by 4',6-diamidino-2-phenylindole (DAPI) staining, was approximately 10(11) cells/g feces. These results suggest that in general, L. thermotolerans is a normal member of the chicken gut microbiota, although it is present at relatively low levels in the feces.     

Streptococcus alactolyticus is the dominating culturable lactic acid bacterium species in canine jejunum and feces of four fistulated dogs

Canine intestinal lactic acid bacterium (LAB) population in four fistulated dogs was cultured and enumerated using MRS agar. LAB levels ranging from 1.4x10(6) to 1.5x10(7) CFU ml(-1) were obtained in jejunal chyme. In the fecal samples 7.0x10(7) and 2.0x10(8) CFU g(-1) were detected. Thirty randomly selected isolates growing in the highest sample dilutions were identified to species level using numerical analysis of 16S and 23S rDNA restriction fragment length polymorphism patterns (ribotyping) and 16S rDNA sequence analysis. According to these results, Streptococcus alactolyticus was the dominant culturable LAB species in both feces and jejunal chyme. In addition, Lactobacillus murinus and Lactobacillus reuteri were detected.     

Urease-producing species of intestinal anaerobes and their activities.

Urease activities of anaerobic bacteria that constituted predominant gut flora were examined. It was demonstrated that some strains of Eubacterium aerofaciens, E. lentum, and Peptostreptococcus products produced urease. They were the most numerous species in human feces. All strains of Bifidobacterium infantis and some strains of Bacteroides multiacidus, B. bifidum, Clostridium symbiosum, Fusobacterium necrophorum, F. varium, Lactobacillus fermentum, Peptococcus asaccharolyticus, and P. prevotii produced urease. The optimum pH of the Lactobacillus urease was found to be 4.0, whereas the pH value of B. multiacidus urease was 8.0.     

Urease-producing species of intestinal anaerobes and their activities.

Urease activities of anaerobic bacteria that constituted predominant gut flora were examined. It was demonstrated that some strains of Eubacterium aerofaciens, E. lentum, and Peptostreptococcus products produced urease. They were the most numerous species in human feces. All strains of Bifidobacterium infantis and some strains of Bacteroides multiacidus, B. bifidum, Clostridium symbiosum, Fusobacterium necrophorum, F. varium, Lactobacillus fermentum, Peptococcus asaccharolyticus, and P. prevotii produced urease. The optimum pH of the Lactobacillus urease was found to be 4.0, whereas the pH value of B. multiacidus urease was 8.0.     

Lactic acid bacteria isolated from canine faeces

AIMS: Lactic acid bacteria (LAB) were isolated and sequenced from the faeces of healthy dogs. Five of these strains were selected and further characterized to clarify the potential of these strains as probiotics for canine. METHODS AND RESULTS: LAB were found in 67% (14/21) of the canine faeces samples when plated on Lactobacilli Selective Media without acetic acid. Out of 13 species identified with partial 16S rRNA gene sequencing, Lactobacillus fermentum LAB8, L. mucosae LAB12, L. rhamnosus LAB11, L. salivarius LAB9 and Weissella confusa LAB10 were selected as candidate probiotic strains based on their frequency, quantity in faeces, growth density, acid tolerance and antimicrobial activity. The minimal inhibitory concentration values of these isolates were determined for 14 antibiotics. L. salivarius LAB9, W. confusa LAB10 and L. mucosae LAB12 were viable in pH 2 for 4 h (mLBS), indicating tolerance to acidity and thus the potential to survive in gastrointestinal tract of the canine. The LAB8-LAB12 strains showed antimicrobial activity against Micrococcus luteus A1 NCIMB86166. CONCLUSIONS: Thirteen different LAB species were found from the faecal microbiota of the healthy canines. Five acid tolerant and antimicrobially active LAB strains with the capacity to grow to high densities both aerobically and anaerobically were chosen to serve as candidate probiotics. SIGNIFICANCE AND IMPACT OF THE STUDY: The selected LAB strains are among the first host-specific LAB with antimicrobial activity isolated from canines that could serve as potential probiotics for canine use.     

Monitoring the bacterial population dynamics in sourdough fermentation processes by using PCR-denaturing gradient gel electrophoresis

Four sourdoughs (A to D) were produced under practical conditions by using a starter mixture of three commercially available sourdough starters and a baker's yeast constitutively containing various species of lactic acid bacteria (LAB). The sourdoughs were continuously propagated until the composition of the LAB flora remained stable. Two LAB-specific PCR-denaturing gradient gel electrophoresis (DGGE) systems were established and used to monitor the development of the microflora. Depending on the prevailing ecological conditions in the different sourdough fermentations, only a few Lactobacillus species were found to be competitive and became dominant. In sourdough A (traditional process with rye flour), Lactobacillus sanfranciscensis and a new species, L. mindensis, were detected. In rye flour sourdoughs B and C, which differed in the process temperature, exclusively L. crispatus and L. pontis became the predominant species in sourdough B and L. crispatus, L. panis, and L. frumenti became the predominant species in sourdough C. On the other hand, in sourdough D (corresponding to sourdough C but produced with rye bran), L. johnsonii and L. reuteri were found. The results of PCR-DGGE were consistent with those obtained by culturing, except for sourdough B, in which L. fermentum was also detected. Isolates of the species L. sanfranciscensis and L. fermentum were shown by randomly amplified polymorphic DNA-PCR analysis to originate from the commercial starters and the baker's yeast, respectively.     

Species composition of intestinal lactoflora of healthy rhesus monkeys

The results of the study of the species composition of the fecal microflora of 15 healthy rhesus macaques, from whom 204 strains of lactobacilli have been isolated and identified, are presented. The intestinal microflora has been shown to include different species, subspecies and biovars of homo- and heterofermentative lactobacilli and to possess definite individual properties. L. acidophilus, mannose-negative biovar I, and L. fermentum, mannose-negative biovars I and II, occur most frequently in feces. Certain differences in the species composition of lactoflora in monkeys and humans have been revealed: in the former, L. fermentum, mannitose-positive biovar III, and L. casei occur considerably more seldom. The inclusion of L. acidophilus strain I L. fermentum strains I and II isolated from rhesus macaques into eubiotics for these monkeys has been suggested.     

Quantitative evaluation of adhesion of lactobacilli isolated from human intestinal tissues to human colonic mucin using surface plasmon resonance (BIACORE assay)

AIMS: To isolate lactobacilli from the mucus layer of the human intestine and evaluate their adhesion abilities using a BIACORE assay. METHODS AND RESULTS: Thirty strains of lactobacilli were isolated from the mucus layer of normal human intestinal tissues using conventional plate culture. The strains were identified using homology comparisons of the 16S rDNA sequence to databases as Lactobacillus salivarius (26%), Lactobacillus fermentum (13%), Lactobacillus gasseri (10%), Lactobacillus paracasei (7%), Lactobacillus casei (3%), Lactobacillus mucosae (3%) and Lactobacillus plantarum (3%). Lactobacillus plantarum LA 318 shows the highest adhesion to human colonic mucin (HCM) using the BIACORE assay at 115.30 +/- 12.37 resonance unit (RU). The adhesion of cell wall surface proteins from strain LA 318 was significantly higher to HCM than to bovine serum albumin (BSA; P < 0.05). CONCLUSIONS: We isolated 30 strains of lactobacilli. Lactobacillus salivarius was the predominant species of lactobacilli isolated in this study. The adhesion of strain LA 318 isolated from human transverse colon to its mucin was shown. The adhesion could be mediated by lectin-like components on the bacterial cell surface. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study where lactobacilli were isolated from human intestinal tissues and shown to adhere to HCM.     

Quantitative PCR with 16S rRNA-gene-targeted species-specific primers for analysis of human intestinal bifidobacteria

A highly sensitive quantitative PCR detection method has been developed and applied to the distribution analysis of human intestinal bifidobacteria by combining real-time PCR with Bifidobacterium genus- and species-specific primers. Real-time PCR detection of serially diluted DNA extracted from cultured bifidobacteria was linear for cell counts ranging from 10(6) to 10 cells per PCR assay. It was also found that the method was applicable to the detection of Bifidobacterium in feces when it was present at concentrations of >10(6) cells per g of feces. Concerning the distribution of Bifidobacterium species in intestinal flora, the Bifidobacterium adolescentis group, the Bifidobacterium catenulatum group, and Bifidobacterium longum were found to be the three predominant species by examination of DNA extracted from the feces of 46 healthy adults. We also examined changes in the population and composition of Bifidobacterium species in human intestinal flora of six healthy adults over an 8-month period. The results showed that the composition of bifidobacterial flora was basically stable throughout the test period.