The bacteriocin piscicolin 126 retains antilisterial activity in vivo.

OBJECTIVE We have conducted a series of experiments to show that the bacteriocin piscicolin 126 (P126) retains antilisterial activity after injection into a mouse. METHODS Groups of mice were challenged intravenously with Listeria monocytogenes and treated with purified P126 at varying times before and after challenge to determine whether administration of this peptide reduced numbers of colonizing L. monocytogenes and the symptoms of listeriosis. RESULTS The bacteriocin P126 retained antilisterial activity after injection into the mouse. During the early time-points of listerial infection, the purified P126 was found to significantly reduce the listerial load in the liver and spleen and, further, that this reduction translated to reduced clinical signs of disease. CONCLUSIONS This is the first report of a Class IIA bacteriocin displaying in vivo antimicrobial activity. Such a result provides preliminary evidence that this class of molecules may be useful in controlling systemic bacterial infections.