Engineered Lactobacillus rhamnosus GG expressing IgG-binding domains of protein G: Capture of hyperimmune bovine colostrum antibodies and protection against diarrhea in a mouse pup rotavirus infection model

Rotavirus-induced diarrhea causes more than 500,000 deaths annually in the world, and although vaccines are being made available, new effective treatment strategies should still be considered. Purified antibodies derived from hyperimmune bovine colostrum (HBC), from cows immunized with rotavirus, were previously used for treatment of rotavirus diarrhea in children. A combination of HBC antibodies and a probiotic strain of Lactobacillus (L. rhamnosus GG) was also found to be more effective than HBC alone in reducing diarrhea in a mouse model of rotavirus infection. In order to further improve this form of treatment, L. rhamnosus GG was engineered to display surface expressed IgG-binding domains of protein G (GB1, GB2, and GB3) which capture HBC-derived IgG antibodies (HBC-IgG) and thus target rotavirus.     

New strain of Pediococcus pentosaceus alleviates ethanol-induced liver injury by modulating the gut microbiota and short-chain fatty acid metabolism

BACKGROUND Intestinal dysbiosis has been shown to be associated with the pathogenesis of alcoholic liver disease(ALD), which includes changes in the microbiota composition and bacterial overgrowth, but an effective microbe-based therapy is lacking. Pediococcus pentosaceus(P. pentosaceus) CGMCC 7049 is a newly isolated strain of probiotic that has been shown to be resistant to ethanol and bile salts. However, further studies are needed to determine whether P. pentosaceus exerts a protective effect on ALD and to elucidate the potential mechanism.AIM To evaluate the protective effect of the probiotic P. pentosaceus on ethanol-induced liver injury in mice.METHODS A new ethanol-resistant strain of P. pentosaceus CGMCC 7049 was isolated from healthy adults in our laboratory. The chronic plus binge model of experimental ALD was established to evaluate the protective effects. Twenty-eight C57BL/6 mice were randomly divided into three groups: The control group received a pairfed control diet and oral gavage with sterile phosphate buffered saline, the EtOH group received a ten-day Lieber-DeCarli diet containing 5% ethanol and oral gavage with phosphate buffered saline, and the P. pentosaceus group received a 5% ethanol Lieber-DeCarli diet but was treated with P. pentosaceus. One dose of isocaloric maltose dextrin or ethanol was administered by oral gavage on day 11, and the mice were sacrificed nine hours later. Blood and tissue samples(liver and gut) were harvested to evaluate gut barrier function and liver injury-related parameters. Fresh cecal contents were collected, gas chromatography–mass spectrometry was used to measure short-chain fatty acid(SCFA) concentrations, and the microbiota composition was analyzed using 16S rRNA gene sequencing.RESULTS The P. pentosaceus treatment improved ethanol-induced liver injury, with lower alanine aminotransferase, aspartate transaminase and triglyceride levels and decreased neutrophil infiltration. These changes were accompanied by decreased levels of endotoxin and inflammatory cytokines, including interleukin-5, tumor necrosis factor-α, granulocyte colony-stimulating factor, keratinocyte-derived protein chemokine, macrophage inflammatory protein-1α and monocyte chemoattractant protein-1. Ethanol feeding resulted in intestinal dysbiosis and gut barrier disruption, increased relative abundance of potentially pathogenic Escherichia and Staphylococcus, and the depletion of SCFA-producing bacteria, such as Prevotella, Faecalibacterium, and Clostridium. In contrast, P. pentosaceus administration increased the microbial diversity, restored the relative abundance of Lactobacillus, Pediococcus, Prevotella, Clostridium and Akkermansia and increased propionic acid and butyric acid production by modifying SCFA-producing bacteria. Furthermore, the levels of the tight junction protein ZO-1, mucin proteins(mucin [MUC]-1, MUC-2 and MUC-4) and the antimicrobial peptide Reg3β were increased after probiotic supplementation.CONCLUSION Based on these results, the new strain of P. pentosaceus alleviated ethanol-induced liver injury by reversing gut microbiota dysbiosis, regulating intestinal SCFA metabolism, improving intestinal barrier function, and reducing circulating levels of endotoxin and proinflammatory cytokines and chemokines. Thus, this strain is a potential probiotic treatment for ALD.     

抗幽门螺杆菌的胃原籍益生菌株的筛选

目的 筛选体外对幽门螺杆菌有拮抗作用的胃原籍益生菌.方法 从健康志愿者溃疡好发部位取黏膜组织标本按常规厌氧菌分离方法 分离鉴定出多株益生菌,对所分离的菌株通过打孔法检测其体外抑制HP的效果,筛选出有拮抗作用的菌株进行体外与HP共同培养检测其抑菌效果,并进行耐酸、耐胆汁实验.结果 从健康成人胃内分离、鉴定出50株益生菌株,体外抑菌实验发现3株具有拮抗HP的作用、能耐酸、耐胆汁的胃原籍益生菌,编号分别为LF011、JBG012和FB013,经鉴定1株为双歧杆菌,2株为乳酸杆菌.结论 胃内具有独特的菌群体系,分离的3株益生菌能体外拮抗HP并能耐酸、耐胆汁.     

Characterization of microcystin-LR removal process in the presence of probiotic bacteria

Toxic cyanobacteria have been reported in lakes and reservoirs in several countries. The presence of toxins in drinking water creates a potential risk of toxin transference for water consumers. Besides chemical and physical methods of cyanotoxin removal from water, biodegradation methods would be useful. The aim of the current study was to identify bacterial removal mechanisms of the hepatotoxin microcystin-LR. This was studied by testing the hypothesis of enzymatic degradation of microcystin-LR in the presence of probiotic lactic acid bacterial and bifidobacterial strains and the participation of the proteolytic system of the bacteria in this process. The results suggest that extracellularly located cell-envelope proteinases are involved in the decomposition of microcystin-LR. In particular, a correlation between proteolytic activity and microcystin removal was found and both these parameters were dependent on glucose as an energy source. In addition, EDTA, which was indicated as a main inhibitor of proteinases of the investigated strain, was shown to limit the rate of microcystin removal. The removal of microcystins was shown to be different from the known microcystin-degradation pathway of Sphingomonas. ¹⁴C-labeled microcystin was not found inside the cells and bacterial cell extracts were not able to remove the toxin, which supports the involvement of extracellularly located proteinases. The results confirm the hypothesis of enzymatic degradation of microcystins in the presence of probiotic bacteria.     

益生菌在幽门螺杆菌根除治疗中的疗效评价

目的观察和评价益生菌联合三联疗法在幽门螺杆菌(HP)根除治疗中的临床疗效。方法将128例HP阳性患者随机平均分成治疗组和对照组,治疗组采用益生菌(乳酸杆菌)联合三联疗法(泮托拉唑,克拉霉素,阿莫西林)抗HP治疗,对照组单纯用三联疗法抗HP治疗,观察两组患者的临床疗效。结果治疗组患者HP的根除率达90.7%,而对照组仅有63.5%,相比存在统计学差异(P<0.01);且治疗组不良反应5.4%明显低于对照组21.7%(P<0.05)。结论益生菌联合三联疗法可提高根除率,减少抗生素的不良反应,可直接用于根除HP的一线首次治疗。     

<Emphasis Type="Italic">Lactobacillus plantarum 299v</Emphasis> Enhances the Concentrations of Fecal Short-Chain Fatty Acids in Patients with Recurrent <Emphasis Type="Italic">Clostridium difficile</Emphasis>-Associated Diarrhea

Our objective was to document how intake of Lactobacillus plantarum 299v affects the concentrations of fecal organic acids during and after metronidazole treatment in 19 patients with recurrent Clostridium difficile-associated diarrhea. Fecal samples were analyzed by gas-liquid chromatography. After intake of metronidazole a significant decrease in total short-chain fatty acids was seen in the placebo group (from 77.1 to 45.5 μmol/g; P=0.028) but not in the Lactobacillus group (79.8–60.4 μmol/g). In addition, a statistically significant difference between treatment groups was noted for butyrate (5.6–1.2 μmol/g in the placebo group vs. 7.6–5.6 μmol/g in the Lactobacillus group; P=0.047). At the end of the study and after cessation of placebo or Lactobacillus, the total short-chain fatty acids rose to the same levels as before antibiotic treatment in the placebo group. Both treatment groups showed a significant decrease in concentrations of succinate at the end of the study in comparison to the time when metronidazole intake was stopped (6.3–1.5 μmol/g in the placebo group versus 9.3–0.9 μmol/g in the Lactobacillus group; P=0.028). The present study of fecal samples from a clinical trial is the first to demonstrate that administration of Lactobacillus plantarum 299v reduces the negative effects of an antibiotic on colonic fermentation. The intake of this probiotic strain may thereby provide an additional benefit for patients with recurrent Clostridium difficile-associated diarrhea.     

Effect of probiotics on intestinal regrowth and bacterial translocation after massive small bowel resection in a rat

Background/Purpose

Because of their ability to inhibit intestinal bacterial overgrowth, probiotics (PROs) have been advocated for the treatment of patients with short bowel syndrome (SBS). This study was conducted to determine the effect of PROs on bacterial translocation and intestinal regrowth after massive small bowel resection in a rat.

Methods

Male Sprague-Dawley rats were divided into 3 experimental groups: sham rats underwent bowel transection and reanastomosis, SBS rats underwent 75% small bowel resection, and SBS-PRO rats underwent bowel resection and were treated with a PRO given in drinking water from day 4 through 14. Intestinal structural changes (bowel circumference, overall bowel and mucosal weight, mucosal DNA and protein, villus height and crypt depth, enterocyte proliferation and enterocyte apoptosis) and bacterial translocation (BT) to mesenteric lymph nodes, liver, portal blood, and peripheral blood were determined on day 15 after operation.

Results

Sham rats exhibited a 20% BT to the mesenteric lymph nodes (level I), liver (level II), and blood (level III). Short bowel syndrome rats demonstrated a 100% BT to lymph nodes (level I) and liver (level II) and 40% translocation to peripheral blood (level III). Treatment with PROs resulted in a significant decrease in BT to all 3 target organs and decreased enterocyte apoptosis compared with SBS-untreated animals. Short bowel syndrome rats showed a significant increase (vs sham) in jejunal and ileal bowel and mucosal weight, mucosal DNA and protein, villus height, and crypt depth. Short bowel syndrome rats also had a greater proliferation index and apoptotic index in both jejunum and ileum compared with sham animals. SBS-PRO rats showed a significant increase (vs SBS rats) in crypt depth in ileum and a mild decrease in apoptotic index in jejunum and ileum, compared with SBS-untreated animals.

Conclusions

In a rat model of SBS, PROs decrease BT through mechanisms which maybe dependent on intestinal mucosal integrity.     

益生菌对婴儿湿疹及特应性湿疹预防作用的系统评价

目的系统评价益生菌对婴儿湿疹及特应性湿疹的预防作用。方法计算机检索PubMed、EMbase、MEDLINE(Ovid)、CENTRAL、CBM和CNKI数据库,收集益生菌预防婴儿湿疹及特应性湿疹的随机对照试验(RCT),检索时限均从建库至2012年2月。由2位评价员根据纳入和排除标准独立筛选文献、提取资料、评价质量和交叉核对后,采用RevMan 5.0软件进行Meta分析。结果最终纳入15个研究,共3 179例患儿。仅纳入8个质量较高的研究进行Meta分析,结果显示:益生菌组婴儿湿疹发生率低于安慰剂组,两组差异有统计学意义[RD=–0.06,95%CI(–0.10,–0.03),P<0.05];益生菌对婴儿特应性湿疹无预防作用[RD=–0.02,95%CI(–0.08,0.03),P>0.05)];益生菌对高危人群[RD=–0.09,95%CI(–0.15,–0.03),P<0.05]和普通人群[RD=–0.05,95%CI(–0.10,0.00),P<0.05]婴儿湿疹均有预防作用。结论益生菌对于婴儿湿疹有一定预防作用,但由于益生菌菌种、剂量、疗程等诸多方面的差异,其对婴儿湿疹及特应性湿疹的具体效应尚需进一步研究加以验证。