CORRELATION OF CELLULAR PHOSPHOLIPID CONTENT WITH NISIN RESISTANCE OF LISTERIA-MONOCYTOGENES SCOTT-A

A nisin-resistant mutant of Listeria monocytogenes Scott A has been characterized by comparing its phospholipid composition with the nisin-sensitive parental strain. The total phospholipids of resistant cells were significantly (P < 0.001) decreased compared to the parental strain. The types of phospholipids isolated from nisin-resistant and sensitive cells were identical, but there was a significant decrease (P < 0.01) in the amount of three individual phospholipids. Nisin-resistant cells were found to bind less nisin and release less phospholipids than sensitive cells when treated with same concentrations of nisin. The cell surface of resistant cells was less hydrophobic compared to sensitive cells, which also may have contributed to the observed nisin resistance. The results suggest that fundamental changes occurred in the membrane structure and function of the resistant mutant as a response to nisin.