Characterisation of the antibacterial properties of a bacterial derived peptidoglycan hydrolase (LysCs4), active against C. sakazakii and other Gram-negative food-related pathogens

Illness caused by the consumption of contaminated food products continues to represent one of the main challenges facing food manufacturers worldwide. Even with current intervention technologies and increased hygiene measures, foodborne illness remains a significant threat to public health. This coupled with the increasing emergence of multidrug resistant pathogens has increased the need for the development of novel technologies for pathogen control. Bacterial derived peptidoglycan hydrolases represent a vast and highly diverse group of enzymes with potential for biocontrol of a range of Gram-positive and Gram-negative foodborne pathogens. In this study, we describe the identification, cloning, expression and purification of a peptidoglycan hydrolase (LysCs4) derived from Cronobacter sakazakii for biocontrol of the aforementioned infant formula pathogen itself. In silico analysis of LysCs4 revealed the gene to display greatest sequence similarity to a putative lysozyme encoded by the lytic Cronobacter phage ES2. Conserved domain analysis of LysCs4 revealed the presence of a single catalytic domain predicted to display O-Glycosyl hydrolase activity and to be a member of the GH24 family. The ability of this enzyme to hydrolyse the peptidoglycan of 25 Gram-negative strains, across 4 different genera, highlights its potential as a novel candidate for biocontrol of C. sakazakii and other Gram-negative food related pathogens.