The present invention relates to novel polypeptides derived from endolysins from a bacteriophage of Clostridium perfringens and to nucleic acid molecules encoding the same, as well as compositions thereof. The invention also provides uses of such polypeptides and nucleic acid molecules in the diagnosis and treatment of conditions and diseases associated with microbial cells such as Clostridium perfringens. In particular, the invention provides a polypeptide having endolysin activity derived from bacteriophage ΦCP51 of Clostridium perfringens and uses thereof.