摘要目的 应用氢气结合甲烷乳果糖呼气试验(LBT)研究腹泻型肠易激综合征(IBS-D)患者中小肠细菌过度生长(SIBO)的发生率和临床特征,并初步探讨利福昔明对IBS-D患者的疗效.方法 纳入2015年3月至2016年1月就诊于北医三院消化科门诊符合罗马Ⅲ标准的IBS-D患者和年龄、性别相匹配的健康志愿者,应用LBT检测1BS-D患者中SIBO发生率并分析IBS-D合并SIBO(IBS-P组)和不合并SIBO(IBS-N组)患者的临床特征及LBT特点.应用利福昔明(0.4g,2次/d)对IBS-D患者进行4周治疗,比较治疗前、后不同组患者临床症状和LBT变化.结果 (1)共纳入84例IBS-D患者和22名健康志愿者(对照组),IBS-D中SIBO发生率为41.67％(35/84),其中单纯氢气呼气试验阳性者27例(77.14％),单纯甲烷呼气试验阳性者5例(14.29％),二者均阳性者3例(8.57％).(2) IBS-P组的体质量指数(BMI)低于IBS-N组[(21.61±0.57)比(23.44±0.54)kg/m2,P＜0.05],最多排便次数少于IBS-N组[(3.85±0.23)比(4.88±0.35)次/d,P＜0.05].(3)IBS-P组、IBS-N组和对照组的口盲传输时间差异无统计学意义.IBS-P组小肠段和结肠段呼气中氢气丰度显著高于对照组和IBS-N组,小肠段和结肠段(160 min处)甲烷丰度高于IBS-N组(均P ＜0.05).(4) IBS-P组、IBS-N组和对照组的平均呼气氢气丰度和甲烷丰度无显著线性相关(均r＜0.35,P＞0.05).(5)IBS-P组接受利福昔明治疗13例,治疗后患者腹痛、腹胀、粪便性状、排便次数和排便不满意度显著好转(均P＜0.05);IBS-N组接受治疗8例,患者粪便性状、排便次数和排便不满意度较治疗前好转(均P＜0.05).(6) IBS-P组患者利福昔明治疗后LBT转阴率为5/13,各时间点呼气中氢气丰度均下降,结肠段(120 min处)更为显著[(34.54±7.32)×10-6比(52.23±9.40)×10-6,P＜0.05];各时间点呼气中甲烷丰度亦有下降,小肠段(80 min处)最为显著[(8.54±0.95) ×10-6比(11.31±0.94)×10-6,P ＜0.05].结论 符合罗马Ⅲ诊断标准的IBS-D患者中约41.67％存在SIBO,氢气结合甲烷LBT较单纯氢气LBT具有更好的检出率;合并SIBO会影响IBS-D患者的营养状况;利福昔明可以显著改善合并SIBO的IBS-D患者的整体临床症状,降低呼气中氢气与甲烷丰度,但对不合并SIBO的IBS-D患者仅对腹泻症状有改善;两组的肠道菌群构成可能存在差异.

abstractsObjective To investigate the prevalence and clinical features of small intestinal bacterial overgrowth (SIBO) in diarrhea-predominant irritable bowel syndrome (IBS-D) patients detected by hydrogen and methane in lactulose breath test (LBT),and to study the effects of rifaximin in IBS-D paticnts.Methods Consecutive patients with IBS-D who met Rome Ⅲ criteria,and gender-and agematched healthy volunteers were enrolled from March 2015 to January 2016 in Peking University Third Hospital.All the ISB-D patients underwent LBT to detect the prevalence of SIBO.The clinical and LBT features of IBS with SIBO (IBS-P group) and without SIBO (IBS-N group) were analyzed.The effects of rifaximin therapy (0.4g,twice per day for 4 weeks) in IBS-D patients were evaluated by comparing changes in clinical features and LBT results after treatment.Results (1) Eighty-four IBS-D patients and 22 healthy controls were enrolled.The prevalence of SIBO in IBS-D patients was 41.67％ (35/84),with 27 (77.14％) only hydrogen-positive,5 (14.29％) methane-positive,and 3 (8.57％) both methane-and hydrogen-positive.(2) The body mass index (BMI) in the IBS-P group was lower than in the IBS-N group [(21.61 ±0.57) vs (23.44 ±0.54) kg/m2,P ＜0.05],the maximum stool frequency was also less than in the IBS-N group [(3.85 ±0.23) vs (4.88 ±0.35) times/day,P ＜0.05].(3) No significant difference was found in oro-cecal transit time (OCTT) among IBS-P,IBS-N and healthy controls.The hydrogen concentration in small intestinal and colonic sections in breath of the IBS-P group was higher than that of both healthy controls and the IBS-N group,while methane concentration in small intestinal and colonic sections (160 min) was higher than that of the IBS-N group (all P ＜ 0.05).(4) There was no linear relationship between mean hydrogen and methane concentrations in LBT among the IBS-P,the IBS-N and healthy control groups (all r ＜ 0.35,P ＞ 0.05).(5) Totally 13 IBS-P patients received rifaximin therapy,in whom the symptoms of abdomen pain,bloating,fecal consistency,stool frequency,and stool satisfactory were significantly improved after treatment (all P ＜ 0.05);8 IBS-N patients received rifaximin therapy,in whom fecal consistency,stool frequency,and satisfactory were significantly improved (all P ＜0.05).(6) And 5/13 of the IBS-P patients receiving rifaximin presented negative LBT results after rifaximin therapy,with lower hydrogen concentration at all the time points,especially in colonic section (120 min) [(34.54 ±7.32) × 10-6 vs (52.23 ±9.40) × 10-6,P ＜0.05] and lower methane concentration especially in small intestinal section (80 min) [(8.54 ± 0.95) × 10-6 vs (11.31 ±0.94) × 10-6,P ＜0.05].Conclusions About 41.67％ of the IBS-D patients meeting Rome Ⅲ criteria have SIBO,which can be better screened by combining hydrogen and methane in LBT compared with only hydrogen in LBT.SIBO can affect nutritional status in IBS-D patients.Rifaximin can improve the systematic symptoms of IBS-D patients with SIBO,also reduce hydrogen and methane concentration in breath,while only improving diarrhea in IBS-D patients without SIBO.Some differences in gut microbiota may exist between IBS-D with and without SIBO.