Clarification of the genomic boundaries of prophage Phi2401a in a Streptococcus suis serotype 9 strain

I read with great interest the article by Wen et al. entitled "Prophage-mediated lysogenic conversion drives virulence evolution and genomic plasticity in Streptococcus suis serotype 9" (1). The study provides a valuable analysis of prophage diversity and evolution ary dynamics in Streptococcus suis.The authors state that "the virulence gene sly (suilysin) was carried as a gene cassette within prophage Phi2401a." Because sly is a major, well-studied virulence determinant of S. suis that has not previously been reported to be prophage-encoded, this conclusion represents a potentially paradigm-shifting claim.Based on independent comparative genomic analysis, the available sequence evidence instead supports the interpretation that sly is chromosomally encoded and lies adjacent to, but outside, the boundaries of prophage Phi2401a.