Protease treatment affects both invasion ability and biofilm formation in Listeria monocytogenes

Microb Pathog. 2008 Jul;45(1):45-52. doi: 10.1016/j.micpath.2008.01.007. Epub 2008 Mar 25.


Listeria monocytogenes is a notably invasive bacterium associated with life-threatening food-borne disease in humans. Several surface proteins have been shown to be essential in the adhesion of L. monocytogenes, and in the subsequent invasion of phagocytes. Because the control of the invasion of host cells by Listeria could potentially hinder its spread in the infected host, we have examined the effects of a protease treatment on the ability of L. monocytogenes to form biofilms and to invade tissues. We have chosen serratiopeptidase (SPEP), an extracellular metalloprotease produced by Serratia marcescens that is already widely used as an anti-inflammatory agent, and has been shown to modulate adhesin expression and to induce antibiotic sensitivity in other bacteria. Treatment of L. monocytogenes with sublethal concentrations of SPEP reduced their ability to form biofilms and to invade host cells. Zymograms of the treated cells revealed that Ami4b autolysin, internalinB, and ActA were sharply reduced. These cell-surface proteins are known to function as ligands in the interaction between these bacteria and their host cells, and our data suggest that treatment with this natural enzyme may provide a useful tool in the prevention of the initial adhesion of L. monocytogenes to the human gut.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Inflammatory Agents, Non-Steroidal / pharmacology*
  • Bacterial Adhesion / drug effects
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Bacterial Toxins / metabolism
  • Biofilms / drug effects*
  • Biofilms / growth & development
  • Cell Line, Tumor
  • Heat-Shock Proteins / metabolism
  • Hemolysin Proteins / metabolism
  • Humans
  • Listeria monocytogenes / chemistry
  • Listeria monocytogenes / drug effects*
  • Listeria monocytogenes / genetics
  • Listeria monocytogenes / physiology
  • Listeriosis / drug therapy
  • Listeriosis / microbiology*
  • Microbial Viability / drug effects
  • Peptide Hydrolases / pharmacology*
  • Serratia marcescens / enzymology


  • Anti-Inflammatory Agents, Non-Steroidal
  • Bacterial Proteins
  • Bacterial Toxins
  • Heat-Shock Proteins
  • Hemolysin Proteins
  • Peptide Hydrolases
  • serratiopeptidase
  • hlyA protein, Listeria monocytogenes