From 20 to 30% of Clostridioides (Clostridium) difficile infection (CDI), patients might develop recurrence of the infection (RCDI) and, after the first recurrence, the risk of further episodes increases up to 60%. Several bacterial virulence factors have been associated with RCDI, including the elevated production of toxins A and B, the presence of a binary toxin CDT, and mutations in the negative regulator of toxin expression, tcdC. Additional factors have shown to regulate toxin production and virulence in C. difficile in RCDI, including the accessory-gene regulator agr, which acts as a positive switch for toxin transcription. Furthermore, adhesion and motility-associated factors, such as Cwp84, SlpA, and flagella, have shown to increase the adhesion efficiency to host epithelia, cell internalization, and the formation of biofilm. Finally, biofilm confers to C. difficile protection from antibiotics and acts as a reservoir for spores that allow the persistence of the infection in the host. In this review, we describe the key virulence factors of C. difficile that have been associated with recurrent infections.

中文翻译：

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与反复感染有关的艰难梭菌（Clostridium）的毒力因子。

从20％到30％的艰难梭菌（Clostridium）艰难梭菌感染（CDI），患者可能发展为感染复发（RCDI），并且在首次复发后，进一步发作的风险增加到60％。几种细菌毒力因子已与RCDI相关，包括毒素A和B的产生增加，二元毒素CDT的存在以及毒素表达的负调控子tcdC的突变。已经显示出其他因素可调节RCDI中艰难梭菌的毒素产生和毒力，包括辅助基因调节剂agr，它可作为毒素转录的正向开关。此外，已经显示出粘附和与运动相关的因子，例如Cwp84，SlpA和鞭毛，可以增加宿主宿主上皮的粘附效率，细胞内在化和生物膜的形成。最后，生物膜赋予艰难梭菌免受抗生素的保护，并充当孢子的储存库，使孢子在宿主体内持久存在。在这篇综述中，我们描述了与反复感染相关的艰难梭菌关键毒力因子。