This is a response to the letter of Biziulevicius and Kazlauskaite, who made a few valuable comments on our recent paper published on the Journal of Applied Microbiology regarding the classification and potential clinic applications as alternative antibiotics of bacterial cell wall hydrolases (BCWH). We confirm that it is of significant practical and theoretical relevance to categorize BCWH according to their sources owing to their strikingly different antibacterial specificities, which are of critical importance to their potential clinic applications. Among the three groups of lytic enzymes, i.e. lysozymes, microlysins and virolysins, virolysins seem to be the most promising alternative antibiotics as a result of a few unique characteristics of this group of lytic enzymes.