Inducible Expression of as a Universal Tool for Studying Sporulation in .

remains a leading nosocomial pathogen, putting considerable strain on the healthcare system. The ability to form endospores, highly resistant to environmental insults, is key to its persistence and transmission. However, important differences exist between the sporulation pathways of and the model Gram-positive organism . Amongst the challenges in studying sporulation in is the relatively poor levels of sporulation and high heterogeneity in the sporulation process. To overcome these limitations we placed regulatory elements upstream of the master regulator of sporulation, , generating a new strain that can be artificially induced to sporulate by addition of anhydrotetracycline (ATc). We demonstrate that this strain is asporogenous in the absence of ATc, and that ATc can be used to drive faster and more efficient sporulation. Induction of Spo0A is titratable and this can be used in the study of the regulon both and , as demonstrated using a mouse model of infection (CDI). Insights into differences between the sporulation pathways in and gained by study of the inducible strain are discussed, further highlighting the universal interest of this tool. The strain provides a useful background in which to generate mutations in genes involved in sporulation, therefore providing an exciting new tool to unravel key aspects of sporulation in