The nine peptidoglycan hydrolases genes in Lactobacillus helveticus are ubiquitous and early transcribed

► In this study we focus on the clonal diversity of the autolysins of L. helveticus. ► The study was performed at molecular level on 24 strains highly diverse. ► We consistently examined the presence, absence and expression of 9 autolysin genes. ► We find that the nine autolysin genes were ubiquitous and early transcripted.