The Phage Holin Holgh15 Exhibits Potential As An Antibacterial Agent To Controllisteria Monocytogenes

Listeria monocytogenesis an important foodborne pathogen that is a serious threat to public health security, and new strategies to control this bacterium in food are needed. HolGH15, derived fromStaphylococcus aureusphage GH15, has shown antibacterial activity against several bacterial species. In this work, the antilisterial behavior and effectiveness of HolGH15 are further studied. To elucidate its antimicrobial modes againstL. monocytogenes, cell integrity and membrane permeabilization assays were performed. When treated with HolGH15, the release of 260-nm-absorbing materials ofL. monocytogeneswas rapidly increased. HolGH15 triggered a significant increase in fluorescence intensity by flow cytometry. In membrane permeabilization assays, the cytoplasmic beta-galactosidase ofL. monocytogenestreated with HolGH15 was released via an increase in the permeability of the membrane. HolGH15 caused changes in the structural properties ofL. monocytogenescells resulting in shrinkage, which evoked the release and removal of cellular contents and finally lead to cell death. Electron microscopy observations indicated that HolGH15 exhibited excellent bactericidal potency by permeabilizing the cell membrane, damaging membrane integrity, and inducing cellular content shrinkage or loss. Moreover, HolGH15 (at the final concentration of 240 mu g/mL) reducedL. monocytogenes(at the initial concentration of 10(6)colony-forming unit/mL) to an undetectable level at 4 degrees C. Collectively, HolGH15 has potential as a novel antimicrobial agent againstL. monocytogenesin the manufacture and store of food by spraying or soaking, especially at refrigerated temperature.