Isolation, purification and partial characterization of a new extracellular cytotoxin from a virulent clinical strain of Listeria monocytogenes serotype 4b, and an avirulent, nonhemolytic variant ATCC 15313 serotype 1/2a
1991
Van der Kelen, D. | Lindsay, J.A.
A number of pathologies of listeric infections in man remain unexplained. The objective of this study was to investigate whether strains of Listeria monocytogenes synthesize additional toxin(s), which may be implicated in these unexplained pathologies. Results showed that both virulent (4b) and avirulent (ATCC 15313) strains of L. monocytogenes synthesize a previously unrecognized extracellular cytotoxin of Mr 34,000. Cytotoxin synthesis is possibly, dependent on the type of salt and the concentration of calcium ions. The cytotoxin is highly thermostable (D121C > 10 min) but is susceptible to digestion by trypsin/chymotrypsin. The cytotoxin is thermostable as the absence of viable L. monocytogenes cells in a food does not preclude the possibility of a toxigenic food product. The role of the cytotoxin in a listeric infection is at present unknown.
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