During infection of bladder epithelial cells, uropathogenic Escherichia coli (UPEC) can stop dividing and grow into highly filamentous forms. Here, we find that some filaments of E. coli UTI89 released from infected cells grow very rapidly and by more than 100 μm before initiating division, whereas others do not survive, suggesting that infection-related filamentation (IRF) is a stress response that promotes bacterial dispersal. IRF is accompanied by unstable, dynamic repositioning of FtsZ division rings. In contrast, DamX, which is associated with normal cell division and is also essential for IRF, is distributed uniformly around the cell envelope during filamentation. When filaments initiate division to regenerate rod cells, DamX condenses into stable rings prior to division. The DamX rings maintain consistent thickness during constriction and remain at the septum until after membrane fusion. Deletion of damX affects vegetative cell division in UTI89 (but not in the model E. coli K-12), and, during infection, blocks filamentation and reduces bacterial cell integrity. IRF therefore involves DamX distribution throughout the membrane and prevention of FtsZ ring stabilization, leading to cell division arrest. DamX then reassembles into stable division rings for filament division, promoting dispersal and survival during infection.

在膀胱上皮细胞感染期间，尿路致病性大肠杆菌（UPEC）可以停止分裂并生长成高度丝状形式。在这里，我们发现从受感染细胞释放的大肠杆菌UTI89 的一些丝状体生长非常迅速，在开始分裂之前生长超过 100 μm，而其他丝状体则无法存活，这表明感染相关丝状化 (IRF) 是一种应激反应，可促进细菌扩散。 IRF 伴随着 FtsZ 分裂环不稳定、动态的重新定位。相比之下，DamX 与正常细胞分裂相关，也是 IRF 所必需的，在丝状形成过程中，DamX 均匀分布在细胞包膜周围。当细丝开始分裂以再生杆状细胞时，DamX 在分裂前凝结成稳定的环。 DamX 环在收缩期间保持一致的厚度，并保留在隔膜上，直到膜融合后。 damX的缺失会影响 UTI89 中的营养细胞分裂（但不会影响模型大肠杆菌K-12），并且在感染过程中会阻碍丝状形成并降低细菌细胞的完整性。因此，IRF 涉及到 DamX 在整个膜上的分布并防止 FtsZ 环稳定，从而导致细胞分裂停滞。然后，DamX 重新组装成稳定的分裂环以进行细丝分裂，从而促进感染期间的扩散和存活。