| 1 | Diarrhoea-predominant irritable bowel syndrome distinguishable by 16S rRNA gene phylotype quantification显示文摘AIM:To study whether selected bacterial 16S ribosomal RNA(rRNA)gene phylotypes are capable of disting- uishing irritable bowel syndrome(IBS). METHODS:The faecal microbiota of twenty volunteers with IBS,subdivided into eight diarrhoea-predominant (IBS-D),eight constipation-predominant(IBS-C)and four mixed symptom-subtype(IBS-M)IBS patients,and fifteen control subjects,were analysed at three time-points with a set of fourteen quantitative real-timepolymerase chain reaction assays.All assays targeted 16S rRNA gene phylotypes putatively associated with IBS,based on 16S rRNA gene library sequence analysis. The target phylotypes were affiliated with Actinobac-teria,Bacteroidetes and Firmicutes.Eight of the target phylotypes had less than 95%similarity to cultured bacterial species according to their 16S rRNA gene sequence.The data analyses were made with repeated-measures ANCOVA-type modelling of the data and principle component analysis(PCA)with linear mixed-effects models applied to the principal component scores. RESULTS:Bacterial phylotypes Clostridium cocleatum 88%,Clostridium thermosuccinogenes 85%,Coprobacillus catenaformis 91%,Ruminococcus bromii-like, Ruminococcus torques 91%,and R.torques 93%were detected from all samples analysed.A multivariate analysis of the relative quantities of all 14 bacterial 16S rRNA gene phylotypes suggested that the intestinal microbiota of the IBS-D patients differed from other sample groups.The PCA on the first principal component(PC1),explaining 30.36%of the observed variation in the IBS-D patient group,was significantly altered from all other sample groups(IBS-D vs control, P=0.01;IBS-D vs IBS-M,P=0.00;IBS-D vs IBS-C, P=0.05).Significant differences were also observed in the levels of distinct phylotypes using relative values in proportion to the total amount of bacteria.A phy- lotype with 85%similarity to C.thermosuccinogenes was quantified in significantly different quantities among the IBS-D and control subjects(-4.08±0.90 vs -3.33±1.16,P=0.04)and IBS-D and IBS-M subjects (-4.08±0.90 vs-3.08±1.38,P=0.05).Furthermore,a phylotype with 94%similarity to R.torques was more prevalent in IBS-D patients'intestinal micro- biota than in that of control subjects(-2.43±1.49 vs -4.02±1.63,P=0.01).A phylotype with 93%simi- larity to R.torques was associated with control sam- ples when compared with IBS-M(-2.41±0.53 vs -2.92±0.56,P=0.00).Additionally,a R.bromii-like phylotype was associated with IBS-C patients in com- parison to control subjects(-1.61±1.83 vs-3.69± 2.42,P=0.01).All of the above mentioned phylotype specific alterations were independent of the effect of time. CONCLUSION:Significant phylotype level alterationsin the intestinal microbiotas of IBS patients were observed,further emphasizing the possible contribution of the gastrointestinal microbiota in IBS. | Anna Lyra Teemu Rinttil Janne Nikkil Lotta Krogius-Kurikka Kajsa Kajander Erja Malinen Jaana Mtt Laura Mkel Airi Palva | 2009 | World Journal of Gastroenterology2009，15，47： | 26 |
| 2 | Association of symptoms with gastrointestinal microbiota in irritable bowel syndrome显示文摘AIM:To investigate the correlations between selfreported symptoms of irritable bowel syndrome(IBS) and the gastrointestinal(GI) microbiota composition.METHODS:Fecal samples were collected from a total of 44 subjects diagnosed with IBS.Their symptoms were monitored with a validated inflammatory bowel disease questionnaire adjusted for IBS patients.Thirteen quantitative real-time polymerase chain reaction assays were applied to evaluate the GI microbiota composition.Eubacteria and GI bacterial genera(Bifidobacterium,Lactobacillus and Veillonella),groups(Clostridium coccoides/Eubacterium rectale,Desulfovibrio desulfuricans) and distinct bacterial phylotypes [closest 16S rDNA sequence resemblance to species Bifidobacterium catenulatum,Clostridium cocleatum,Collinsella aerofaciens(C.aerofaciens),Coprococcus eutactus(C.eutactus),Ruminococcus torques and Streptococcus bovis ] with a suspected association with IBS were quantified.Correlations between quantities or presence/absence data of selected bacterial groups or phylotypes and various IBSrelated symptoms were investigated.RESULTS:Associations were observed between subjects' self-reported symptoms and the presence or quantities of certain GI bacteria.A Ruminococcus torques(R.torques)-like(94% similarity in 16S rRNA gene sequence) phylotype was associated with severity of bowel symptoms.Furthermore,among IBS subjects with R.torques 94% detected,the amounts of C.cocleatum 88%,C.aerofaciens-like and C.eutactus 97% phylotypes were significantly reduced.Interesting observations were also made concerning the effect of a subject's weight on GI microbiota with regard to C.aerofaciens like phylotype,Bifidobacterium spp.and Lactobacillus spp.CONCLUSION:Bacteria seemingly affecting the symptom scores are unlikely to be the underlying cause or cure of IBS,but they may serve as biomarkers of the condition. | Erja Malinen Lotta Krogius-Kurikka Janne Nikkil Airi Palva Anna Lyra Anne Jskelinen Teemu Rinttil Terttu Vilpponen-Salmela Atte Johannes von Wright | 2010 | World Journal of Gastroenterology2010，16，36： | 13 |
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