ABSTRACT
Clostridioides difficile is a causative agent of antibiotic-associated diarrhea as well as pseudomembranous colitis. So far, all known bacteriophages infecting these bacteria are temperate, which means that instead of prompt lysis of host cells, they can integrate into the host genome or replicate episomally. While C. difficile phages are capable of spontaneous induction and entering the lytic pathway, very little is known about the regulation of their maintenance in the state of lysogeny. In this study, we investigated the properties of a putative major repressor of the recently characterized C. difficile phiCDKH01 bacteriophage. A candidate protein belongs to the XRE family and controls the transcription of genes encoding putative phage antirepressors, known to be involved in the regulation of lytic development. Hence, the putative major phage repressor is likely to be responsible for maintenance of the lysogeny.