Division of Medical Microbiology, The Johns Hopkins Medical Institutions, Baltimore, Maryland 21205, USA.
Annu Rev Microbiol. 2011;65:501-21. doi: 10.1146/annurev-micro-090110-102824.
Clostridium difficile is an anaerobic, spore-forming, gram-positive rod that causes a spectrum of antibiotic-associated colitis through the elaboration of two large clostridial toxins and other virulence factors. Since its discovery in 1978 as the agent responsible for pseudomembranous colitis, the organism has continued to evolve into an adaptable, aggressive, hypervirulent strain. Advances in molecular methods and improved animal models have facilitated an understanding of how this organism survives in the environment, adapts to the gastrointestinal tract of animals and humans, and accomplishes its unique pathogenesis. The advances in microbiology have been accompanied by some important clinical observations including increased rates of C. difficile infection, increased virulence, and multiple outbreaks. The major new risk is fluoroquinolone use; there is also an association with proton pump inhibitors and increased recognition of cases in outpatients, pediatric patients, and patients without recent antibiotic use. The combination of more aggressive strains with mobile genomes in a setting of an expanded pool of individuals at risk has refocused attention on and challenged assumptions regarding diagnostic gold standards. Future research is likely to build upon the advancements in phylogenetics to create novel strategies for diagnosis, treatment, and prevention.
艰难梭菌是一种厌氧、产芽孢、革兰阳性杆菌，通过产生两种大的梭菌毒素和其他毒力因子，引起一系列抗生素相关性结肠炎。自 1978 年发现该菌是导致伪膜性结肠炎的病原体以来，其不断进化为一种适应性强、侵袭性强、高毒力的菌株。分子方法的进步和改良的动物模型促进了人们对该病原体如何在环境中生存、适应动物和人类的胃肠道以及完成其独特发病机制的理解。微生物学的进步伴随着一些重要的临床观察结果，包括艰难梭菌感染率增加、毒力增加和多次暴发。主要的新风险是氟喹诺酮类药物的使用；质子泵抑制剂也与之相关，并且在门诊患者、儿科患者和近期未使用抗生素的患者中，此类病例的检出率也有所增加。在风险人群扩大的背景下，具有侵袭性更强的菌株和可移动基因组，这重新引起了人们对诊断金标准的关注，并对其假设提出了挑战。未来的研究可能会在系统发生学的进展基础上，建立用于诊断、治疗和预防的新策略。
