Exploratory Pilot Studies to Demonstrate Mechanisms of Preventing Antibiotic-Associated Diarrhea and the Role for Probiotics

摘要 益生菌是活的微生物，当摄入足够量时，可为健康带来益处 主机。益生菌治疗最常见的适应症之一是预防抗生素相关疾病 腹泻（AAD）。不幸的是，许多用于 AAD 的益生菌产品的功效并没有得到以下证据的支持： 严格的独立研究和基于非证据的临床使用很常见。来自多项研究的数据 表明抗生素诱导的结肠共生细菌破坏导致短期内显着减少 最终，链脂肪酸（SCFA）的产生以及钠依赖性液体吸收的相应减少 导致AAD。益生菌菌株动物双歧杆菌亚种。乳酸 BB-12 (BB-12) 已被证明可以 改善多种胃肠道疾病状态，并已知会产生醋酸盐——最丰富的醋酸盐 原代结肠 SCFA – 体外浓度高达 50 mM。因此，我们假设并发 BB-12 与抗生素联合给药可通过 BB-12 的能力来防止 AAD 的发生 两者都直接产生乙酸，并通过交叉喂养某些细菌来增加其他SCFA 厚壁菌门。例如，梭状芽胞杆菌、真杆菌和罗斯伯利亚使用乙酸盐生产丁酸盐， 另一种常见的 SCFA。 R61 阶段（N=60）的主要目的是确定 BB-12 是否可以缓解 抗生素引起的 SCFA 浓度降低，反映在粪便醋酸盐水平上。我们假设 抗生素会减少粪便 SCFA，但补充 BB-12 可以预防抗生素诱导的 SCFA 与对照相比，减少和/或与更快恢复到基线 SCFA 水平相关。 抗生素的施用还会降低肠道微生物群的微生物总数和多样性，从而破坏 肠道生态系统的稳态并允许病原体定植。次要目标使用 16S rDNA 分析以确定 BB-12 是否抑制抗生素引起的肠道微生物群破坏。我们假设 抗生素会减少粪便微生物群中细菌种类的总数和多样性， 同时补充 BB-12 将最大限度地减少抗生素引起的微生物群变化，和/或将 与对照相比，恢复到基线微生物群组成的时间较短。在R33阶段 (N=108)，为了进一步描述 BB-12 给药对抗生素耗尽的肠道微生物群的影响，我们 将评估四个随机分组的益生菌给药时间：1) BB-12 酸奶 与抗生素同时服用； 2）控制酸奶与抗生素同时食用； 3） 抗生素使用后四小时饮用BB-12酸奶； 4) 对照饮用后四小时的酸奶 抗生素。我们的长期目标是确定 BB-12 对多种胃肠道疾病状态的影响 和年龄。阐明作用机制对于塑造未来的方向至关重要 益生菌功效的转化研究。

Abstract Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. One of the most common indications for probiotic treatment is the prevention of antibiotic-associated diarrhea (AAD). Unfortunately, the efficacy of many probiotic products used for AAD is not supported by rigorous independent research, and non-evidence-based clinical usage is common. Data from several studies suggest antibiotic-induced disruption of commensal colonic bacteria results in a significant reduction in short chain fatty acid (SCFA) production and a concomitant reduction in Na-dependent fluid absorption, ultimately resulting in AAD. The probiotic strain Bifidobacterium animalis subsp. lactis BB-12 (BB-12) has been shown to ameliorate a variety of gastrointestinal disease states and is known to produce acetate – the most abundant primary colonic SCFA – at concentrations of up to 50 mM in vitro. Thus, we hypothesize that the concurrent administration of BB-12 with antibiotics will protect against the development of AAD by the ability of BB-12 to both generate acetate directly, and increase other SCFAs through cross-feeding of certain bacteria in the Firmicutes phylum. For example, Clostridium, Eubacterium and Roseburia use acetate to produce butyrate, another common SCFA. The primary aim of the R61 phase (N=60) is to determine if BB-12 can mitigate antibiotic-induced reduction in SCFA concentration, as reflected in fecal acetate levels. We hypothesize that antibiotics will decrease fecal SCFAs, but BB-12 supplementation will protect against antibiotic-induced SCFA reduction, and/or be associated with quicker restoration to baseline SCFA levels as compared to control. Antibiotic administration also lowers total microbial counts and diversity in the gut microbiota, disrupting the homeostasis of the gut ecosystem and allowing colonization by pathogens. The secondary aim uses 16S rDNA profiling to determine if BB-12 inhibits antibiotic-induced disruption of the gut microbiota. We hypothesize that antibiotics will diminish the overall number and diversity of bacterial species present in the fecal microbiota, and concurrent BB-12 supplementation will minimize antibiotic-induced shifts in the microbiota, and/or will be associated with shorter recovery to baseline microbiota composition as compared to control. In the R33 phase (N=108), to further delineate the effects of BB-12 administration on the antibiotic-depleted gut microbiota, we will evaluate the timing of probiotic administration in four randomly assigned groups: 1) BB-12 yogurt consumed at the same time as the antibiotic; 2) control yogurt consumed at the same time as the antibiotic; 3) BB-12 yogurt consumed four hours after the antibiotic; and 4) control yogurt consumed four hours after the antibiotic. Our long-term goal is to determine the impact of BB-12 on a variety of gastrointestinal disease states and ages. Elucidation of the mechanism(s) of action will be integral in shaping the direction of future translational research on probiotic effectiveness.