Combined Effect of Enterocin and Lipase From Enterococcus faecium NCIM5363 Against Food Borne Pathogens: Mode of Action Studies.

Food borne diseases have a major impact on
public health whose epidemiology is rapidly changing. The
whole cells of pathogens involved or their toxins/metabolites
affect the human health apart from spoiling sensory
properties of the food products finally affecting the food
industry as well as consumer health. With pathogens
developing mechanisms of antibiotic resistance, there has
been an increased need to replace antibiotics as well as
chemical additives with naturally occurring bacteriocins.
Bacteriocins are known to act mainly against Gram-positive
pathogens and with little or no effect towards Gramnegative
enteric bacteria. In the present study, combination
effect of lipase and bacteriocin produced by Enterococcus
faecium NCIM5363, a highly lipolytic lactic acid bacterium
against various food pathogens was assessed. The
lipase in combination with enterocin exhibited a lethal
effect against Gram-negative pathogens. Scanning electron
microscopy studies carried out to ascertain the constitutive
mode of action of lipase and enterocin revealed that the
lipase degrades the cell wall of Gram-negative bacteria and
creates a pore through which enterocin enters thereby
resulting in cell death. The novelty of this work is the fact
that this is the first report revealing the synergistic effect of
lipase with enterocin against Gram-negative bacteria.