Fecal microbiota transplant rescues mice from sepsis. Mus musculus

The aim of this study was to test the hypothesis that replenishing the microbiota with a fecal microbiota transplant (FMT) can rescue a host from an advanced stage of sepsis. We developed a clinically-relevant mouse model of lethal polymicrobial gut-derived sepsis in mice using a 4-member pathogen community (Candida albicans, Klebsiella oxytoca, Serratia marcescens, Enterococcus faecalis) isolated from a critically ill patient. In order to mimic pre-operative surgical patient condition mice were exposed to food restriction and antibiotics. Approximately 18 hours prior to surgery food was removed from the cages and the mice were allowed only tap water. Each mouse received an intramuscular Cefoxitin injection 30 minutes prior to the incision at a concentration of 25 mg/kg into the left thigh. Mice were then subjected to a midline laparotomy, 30% hepatectomy of the left lateral lobe of the liver and a direct cecal inoculation of 200 µL of the four pathogen community. On postoperative day one, the mice were administered rectal enema. Mice were given either 1 ml of fecal microbiota transplant (FMT) or an autoclaved control (AC). This was again repeated on postoperative day two. Mice were then followed for mortality. Chow was restored to the cages on postoperative day two, approximately 45 hours after the operation. The injection of fecal microbiota transplant by enema significantly protected mice survival, reversed the composition of gut microflora and down-regulated the host inflammatory response. Overall design: The cecum, left lobe of the liver, and spleen were isolated from mice for microarray processing with three or more replicates for six expermental conditions: non-treated control, SAHC POD1, SAHC.AC POD2, SAHC.FMT POD2, SAHC.AC POD7, SAHC.FMT POD7

本研究旨在验证以下假说：通过粪便菌群移植（Fecal Microbiota Transplant, FMT）补充宿主肠道菌群，可使宿主从脓毒症晚期中获救。
我们采用从重症患者体内分离的4株病原体群落（白色念珠菌*Candida albicans*、产酸克雷伯菌*Klebsiella oxytoca*、黏质沙雷菌*Serratia marcescens*、粪肠球菌*Enterococcus faecalis*），构建了与临床场景高度相关的致死性多菌型肠道源性脓毒症小鼠模型。
为模拟外科术前患者的生理状态，小鼠接受禁食与抗生素预处理：手术前约18小时移除笼内饲料，仅提供自来水；每只小鼠于切口前30分钟，于左侧大腿肌内注射25 mg/kg的头孢西丁溶液。
随后对小鼠实施正中剖腹术，切除肝脏左外侧叶30%的肝组织，并直接向盲肠接种200 μL上述4株病原体混合群落。
术后第一天，对小鼠进行直肠灌肠给药：分别给予1 mL粪便菌群移植（FMT）或高压灭菌对照（AC）；该给药操作于术后第二天重复一次。
此后持续监测小鼠的生存情况。术后第二天，即术后约45小时，恢复笼内饲料供应。
实验结果表明，经灌肠途径给予的粪便菌群移植可显著提升小鼠存活率，逆转肠道菌群组成，并下调宿主的炎症反应水平。
整体实验设计：从受试小鼠体内分离盲肠、肝脏左叶与脾脏样本进行微阵列分析，每组实验设置3次及以上生物学重复，共涵盖6组实验条件：未处理对照组、SAHC POD1、SAHC.AC POD2、SAHC.FMT POD2、SAHC.AC POD7、SAHC.FMT POD7