Ribosome deficiency induces <i>Salmonella</i> filamentation within host cells

Bacteria growing inside host cells encounter various stresses and have evolved multiple adaptive mechanisms. One such mechanism is morphological changes, such as from rod-shaped cells to filaments. <i>Salmonella</i> is a rod-shaped pathogen that infects over 100 million people each year as well as numerous farmed animals. In this work, we present new findings that slowing down protein synthesis causes <i>Salmonella</i> to filament inside mammalian host cells. Combining genetic, molecular, and cell biology approaches, we demonstrate that filamentation of Salmonella cells is caused by translational and transcriptional regulation of the histidine operon. Filamentous cells appear to tolerate acid stress better and resume cell division after the stress is removed. This work highlights intriguing translational control of bacterial cell division and morphology, which may facilitate <i>Salmonella</i> cells to adapt to the host environment.