Community-based interference against integration of Pseudomonas aeruginosa into human salivary microbial biofilm

As part of the human gastrointestinal tract, the oral cavity represents a complex biological system and harbors diverse bacterial species. Unlike the gut microbiota, which is often considered a health asset, studies of the oral commensal microbiota have been largely limited to their implication in oral conditions such as dental caries and periodontal disease. Less emphasis has been given to their potential beneficial roles, especially the protective effects against oral colonization by foreign or pathogenic bacteria. In this study, we used salivary microbiota derived from healthy human subjects to investigate protective effects against colonization and integration of Pseudomonas aeruginosa, an opportunistic bacterial pathogen, into developing or pre-formed salivary biofilms. When co-cultivated in saliva medium, P. aeruginosa persisted in the planktonic phase, but failed to integrate into the salivary microbial community during biofilm formation. Furthermore, in saliva medium supplemented with sucrose, the oral microbiota inhibited the growth of P. aeruginosa by producing lactic acid. More interestingly, while pre-formed salivary biofilms were able to prevent P. aeruginosa colonization, the same biofilms recovered from mild chlorhexidine gluconate treatment displayed a shift in microbial composition and showed a drastic reduction in protection. Our study indicates that normal oral communities with balanced microbial compositions could be important in effectively preventing the integration of foreign or pathogenic bacterial species, such as P. aeruginosa.     

海洋硫酸多糖对糖脂代谢及肠道菌群调节作用的研究进展

肥胖已经成为人类首要健康问题,海洋硫酸多糖对糖脂代谢及肠道菌群具有调节作用,因此在肥胖预防和缓解中展现出良好的应用前景。本文综述了海洋硫酸多糖的种类,并从糖脂代谢和肠道微生物群的角度总结了海洋硫酸多糖在肥胖预防和缓解中的作用机制,提出了海洋硫酸多糖未来的研究和发展方向,以及为海洋硫酸多糖的进一步研究及市场化应用提供参考。     

基于肠道菌群探讨甘草泻心汤对伊立替康致小鼠腹泻的影响

目的 研究甘草泻心汤对化疗相关腹泻小鼠肠道菌群的影响。方法 将小鼠随机分为对照组、模型组、洛哌丁胺（阳性药,0.4 mg·kg^-1）组和甘草泻心汤高、低剂量（16.4、4.1 g·kg^-1）组;采用连续4 d ip 55 mg·kg^-1伊立替康诱导小鼠化疗相关腹泻模型;记录小鼠首次排便时间、稀便级、稀便率和腹泻指数;采用试剂盒测定小鼠肠道消化酶活力及炎症因子水平;采用高通量测序技术分析结肠内容物肠道菌群变化。结果 与对照组比较,模型组小鼠首次排便时间显著缩短（P<0.01）,稀便级、稀便率和腹泻指数显著升高（P<0.01）;消化酶乳酸脱氢酶（LDH）、淀粉酶（AMS）和脂肪酶（LPS）活力显著降低（P<0.01）;炎症因子白细胞介素1β （IL-1β）、环氧化酶2 （COX-2）、细胞间黏附分子1 （ICAM-1）和肿瘤坏死因子α （TNF-α）水平显著升高（P<0.01）;肠道菌群α多样性Simpson指数显著升高（P<0.05）;肠道菌群β多样性差异较大;变形菌门、梭杆菌门、变形菌纲、梭杆菌纲、肠杆菌目、梭杆菌目、拟杆菌科、丹毒丝菌科、埃格特菌科和拟杆菌属丰度显著升高（P<0.01）,Muribaculaceae和norank_f__Muribaculaceae丰度显著降低（P<0.01）。与模型组比较,甘草泻心汤高、低剂量组小鼠首次排便时间显著延长（P<0.05、0.01）、稀便率和腹泻指数显著降低（P<0.05、0.01）,高剂量组稀便级显著降低（P<0.01）;高、低剂量组各消化酶活力显著回升（P<0.05、0.01）;高、低剂量组各炎症因子水平显著降低（P<0.05、0.01）;高剂量组Simpson指数显著降低（P<0.05）,β多样性更趋近对照组,显著回调各优势物种丰度的显著性变化（P<0.05、0.01）。结论 甘草泻心汤对于伊立替康诱导的腹泻小鼠具有明显的治疗作用,可能是其通过调整腹泻小鼠肠道菌群实现。     

Effect of antibiotic-administration period on hepatic bile acid profile and expression of pharmacokinetic-related proteins in mouse liver,kidney, and brain capillaries

Antibiotic administration affects pharmacokinetics through changes in the intestinal microbiota, and bile acids are involved in this regulation. The purpose of the present study was to clarify the effect of different periods of antibiotic administration on the hepatic bile acid profile and expression of pharmacokinetic-related proteins in mouse liver, kidney, and brain capillaries. Vancomycin and polymyxin B were orally administered to mice for either 5- or 25-days. The hepatic bile acid profile of the 25-day treatment group was distinct. In the liver, the protein expression of cytochrome P450 (Cyp)3a11 showed the greatest reduction to 11.4% after the 5-day treatment and further reduced to 7.01% after the 25-day treatment. Similar reductions were observed for sulfotransferase 1d1, Cyp2b10, carboxylesterase 2e, UDP-glucuronosyltransferase (Ugt)1a5, and Ugt1a9. In the kidney and brain capillaries, no drug-metabolizing enzymes or drug transporters were changed with >1.5-fold or <0.66-fold statistical significance in either period. These results suggest that bile acids and metabolizing enzymes in the liver are affected in a period-dependent manner by antibiotic treatment, while the blood-brain barrier and kidneys are less affected. Drug-drug interactions of antibiotics via the intestinal microbiota should be considered by changing drug metabolism in the liver.     

Rabdosia serra alleviates dextran sulfate sodium salt-induced colitis in mice through anti-inflammation,regulating Th17/Treg balance,maintaining intestinal barrier integrity,and modulating gut microbiota

Rabdosia serra (R. serra), an important component of Chinese herbal tea, has traditionally been used to treat hepatitis, jaundice, cholecystitis, and colitis. However, the chemical composition of R. serra and its effect against colitis remain unclear. In this study, the chemical composition of the water extract of R. serra was analyzed using ultra performance liquid chromatography coupled with a hybrid linear ion trap quadrupole-orbitrap mass spectrometer (UPLC-LTQ-Orbitrap-MS). A total of 46 compounds, comprising ent-kaurane diterpenoids, flavonoids, phenolic acids, and steroids, were identified in the water extract of R. serra, and the extract could significantly alleviate dextran sulfate sodium salt-induced colitis by improving colon length, upregulating anti-inflammatory factors, downregulating proinflammatory factors, and restoring the balance of T helper 17/T regulatory cells. R. serra also preserved intestinal barrier function by increasing the level of tight junction proteins (zonula occludens 1 and occludin) in mouse colonic tissue. In addition, R. serra modulated the gut microbiota composition by increasing bacterial richness and diversity, increasing the abundance of beneficial bacteria (Muribaculaceae, Bacteroides, Lactobacillus, and Prevotellaceae_UCG-001), and decreasing the abundance of pathogenic bacteria (Turicibacter, Eubacterium_fissicatena_group, and Eubacterium_xylanophilum_group). Gut microbiota depletion by antibiotics further confirmed that R. serra alleviated colitis in a microbiota-dependent manner. Overall, our findings provide chemical and biological evidence for the potential application of R. serra in the management of colitis.     

Gut microbiota differs a decade after bariatric surgery relative to a nonsurgical comparison group

BackgroundFew studies have assessed differences in the gut microbiota composition after bariatric surgery in the long term or whether differences are correlated with remission of type 2 diabetes.ObjectivesThis observational study assessed differences in the gut microbiota between individuals at up to 13 years after surgery and a comparison group of individuals with severe obesity. The relationship between type 2 diabetes remission and the gut microbiota was also assessed.SettingUniversity.MethodsStool samples were collected from individuals completing bariatric surgery (surgery group; n = 16) and individuals with severe obesity that did not receive surgery (nonsurgery group; n = 19) as part of the 12-year follow-up in the Utah Obesity Study. Metabolic health data were collected at baseline and the follow-up examination. The gut microbiota was quantified by sequencing the V4 region of the 16 S rRNA gene. Significant differences in microbiota composition with surgery and other covariates were determined by Unifrac distance analysis and permutational multivariate analysis of variance. Significant differences in the relative abundance of individual bacterial taxa were assessed using analysis of composition of microbiomes software.ResultsThe surgery group had higher relative abundances of Verrucomicrobiaceae (5.7 ± 1.3% versus 1.1 ± .3%) and Streptococcaceae (6.3 ± 1.0% versus 3.2 ± .8%), but lower relative abundances of Bacteroidaceae (8.8 ± 1.8% versus 18.6 ± 2.3%) 10.6 years after surgery. In a small subset of 8 individuals, a higher relative abundance of Akkermansia muciniphila was correlated with type 2 diabetes remission.ConclusionsDifferences in the gut microbiota are evident a decade after bariatric surgery compared with individuals with severe obesity that did not undergo surgery. The observed long-term differences are consistent with previous findings.     

Relationship between human immunodeficiency virus (HIV-1) infection and chronic periodontitis

Introduction: Current studies show that, even in the era of antiretroviral therapies, HIV-1 infection is associated with more severe and frequent refractory chronic periodontitis.

Areas covered: This review, based on a systematic analysis of the literature, intends to provide an update on factors that may be involved in the pathogenesis of periodontal disease in HIV-1-infected patients, including local immunosuppression, oral microbial factors, systemic inflammation, salivary markers, and the role of gingival tissue as a possible reservoir of HIV-1.

Expert commentary: The therapeutic revolution of ART made HIV-1 infection a chronic controllable disease, reduced HIV-1 mortality rate, restored at least partially the immune response and dramatically increased life expectancy of HIV-1-infected patients. Despite all these positive aspects, chronic periodontitis assumes an important role in the HIV-1 infection status for activating systemic inflammation favoring viral replication and influencing HIV-1 status, and also acting as a possible reservoir of HIV-1. All these issues still need to be clarified and validated, but have important clinical implications that certainly will benefit the diagnosis and management of chronic periodontitis in HIV-1-infected patients, and also contributes to HIV-1 eradication.     

Intestinal microbiota in infants at high risk for allergy: Effects of prebiotics and role in eczema development

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Rapid changes in the gut microbiome during human evolution

Humans are ecosystems containing trillions of microorganisms, but the evolutionary history of this microbiome is obscured by a lack of knowledge about microbiomes of African apes. We sequenced the gut communities of hundreds of chimpanzees, bonobos, and gorillas and developed a phylogenetic approach to reconstruct how present-day human microbiomes have diverged from those of ancestral populations. Compositional change in the microbiome was slow and clock-like during African ape diversification, but human microbiomes have deviated from the ancestral state at an accelerated rate. Relative to the microbiomes of wild apes, human microbiomes have lost ancestral microbial diversity while becoming specialized for animal-based diets. Individual wild apes cultivate more phyla, classes, orders, families, genera, and species of bacteria than do individual humans across a range of societies. These results indicate that humanity has experienced a depletion of the gut flora since diverging from Pan.The human microbiome is shaped by host genetics, environment, and lifestyle (1–3); thus, humanity''s unique evolutionary and cultural histories must have altered our associations with microorganisms (4). Despite intensive investigation of the microbiomes of humans spanning a range of geographic locations and cultures (5–7), how the composition of the microbiome has changed since humans diverged from other species, and since human populations diverged from one another, remains unclear, owing to a lack of knowledge about the microbiomes of ancestral hominid populations.Understanding how the composition of the human microbiome has changed over evolutionary time requires the inclusion of the microbiomes of phylogenetic outgroups (i.e., the African apes) into analyses of human microbiomes. Previous comparisons of the gut microbiomes of humans and the African apes have been restricted to just a few individuals per host species (8), precluding detection of the precise compositional differences that distinguish the microbiomes of the host species. Comparing the microbiomes of populations of chimpanzees, bonobos, gorillas, and humans while considering the phylogenetic relatedness among the hosts can reveal how the composition of the microbiome has changed since the host species diversified.Here we used a phylogenetic approach to identify the shifts in the composition of the microbiome that occurred along the lineages leading to the extant species of Homo and Pan. This analysis shows that humans across a range of cultures and geographies harbor microbiomes that are disproportionately divergent from those within wild apes. In particular, among the living hominid species, humans harbor uncharacteristically low levels of microbial diversity within their gut microbiomes.