Department of Microbiology & Immunology, The University of Michigan, Ann Arbor, MI, 48109, USA.
Gut Microbes. 2011 May-Jun;2(3):145-58. doi: 10.4161/gmic.2.3.16333. Epub 2011 May 1.
Clostridium difficile infection (CDI) arises in the setting of antibiotic administration where disruption of the normal indigenous gut microbiota leads to susceptibility to C. difficile colonization and colitis. Using a murine model of CDI, we demonstrate that changes in the community structure of the indigenous gut microbiota are associated with the loss of colonization resistance against C. difficile. Several antibiotic regimens were tested in combination for the ability to overcome colonization resistance, including a five antibiotic cocktail consisting of kanamycin, gentamicin, colistin, metronidazole, and vancomycin administered in drinking water for three days, a single intraperitoneal dose of clindamycin or 10 days of cefoperazone in drinking water. Following antibiotic treatment animals were challenged with 105 colony forming units of C. difficile strain VPI 10463 via oral gavage. Animals that received the antibiotic cocktail and clindamycin prior to C. difficile challenge followed one of two clinical courses, either becoming clinically ill and moribund within 2-4 days post challenge, or remaining clinically well. Animals that became clinically ill developed histologically severe colitis. These histopathologic findings were significantly less severe in animals that remained clinically well. Analysis of 16S rRNA gene sequences retrieved from gut tissue at necropsy demonstrated that Proteobacteria dominated the gut microbiota in clinically ill animals. In contrast, the gut microbial community of clinically well animals more closely resembled untreated animals, which were dominated by members of the Firmicutes. All animals that received cefoperazone treatment prior to C. difficile challenge were clinically ill and moribund by 2-5 days post challenge in a dose dependent manner. The gut communities in these animals were dominated by C.difficile suggesting that cefoperazone treatment resulted in a greater loss in colonization resistance. Thus, the severity of colitis that arises in this system reflects the interplay between the expansion of C. difficile in the gut community and the ecologic dynamics of the indigenous microbial community as it recovers from antibiotic perturbation. We demonstrate that altering the balance of these two opposing processes alters clinical outcome and thus may lead to novel preventative and therapeutic approaches for CDI.
艰难梭菌感染（CDI）发生在使用抗生素的情况下，在此期间，正常的本土肠道微生物群被破坏，导致对艰难梭菌定植和结肠炎的易感性。我们使用艰难梭菌感染的小鼠模型证明，本土肠道微生物群的群落结构变化与对抗艰难梭菌定植的抗性丧失有关。我们测试了几种抗生素联合治疗方案以克服定植抗性，包括在饮用水中连续三天给予卡那霉素、庆大霉素、黏菌素、甲硝唑和万古霉素的五抗生素鸡尾酒，单次腹腔内给予克林霉素或 10 天饮用水中给予头孢哌酮。抗生素治疗后，通过口服灌胃用 105 个 CFU 的艰难梭菌 VPI 10463 菌株对动物进行攻毒。在艰难梭菌攻毒前接受抗生素鸡尾酒和克林霉素治疗的动物有两种临床病程之一，要么在攻毒后 2-4 天内临床病重并濒死，要么保持临床良好。临床病重的动物出现组织学严重结肠炎。在临床良好的动物中，这些组织病理学发现明显较轻。对尸检时从肠道组织中提取的 16S rRNA 基因序列进行分析表明，在临床病重的动物中，变形菌门主导肠道微生物群。相比之下，临床良好动物的肠道微生物群落更接近未经处理的动物，其主要由厚壁菌门成员组成。在艰难梭菌攻毒前接受头孢哌酮治疗的所有动物在攻毒后 2-5 天内以剂量依赖的方式临床病重并濒死。这些动物的肠道群落由艰难梭菌主导，表明头孢哌酮治疗导致定植抗性的更大丧失。因此，该系统中出现的结肠炎严重程度反映了艰难梭菌在肠道群落中的扩张与抗生素干扰后本土微生物群落恢复的生态动力学之间的相互作用。我们证明，改变这两个相反过程的平衡会改变临床结果，从而可能为 CDI 提供新的预防和治疗方法。
