Action of lysozyme and nisin mixtures against lactic acid bacteria

• Published in: International journal of food microbiology Vol. 60; no. 1; pp. 25 - 32
• Main Authors: Chung, Wilfred, Hancock, Robert E.W
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15-09-2000; Elsevier
• Subjects: Animals; Anti-Bacterial Agents - pharmacology; Biological and medical sciences; Drug Synergism; Food industries; Food Microbiology; Food Preservatives; Food spoilage; Fundamental and applied biological sciences. Psychology; Gram-Positive Bacteria - drug effects; Gram-Positive Bacteria - physiology; Gram-Positive Bacteria - ultrastructure; Lactic acid bacteria; Lactobacillus - drug effects; Lactobacillus - physiology; Lactobacillus - ultrastructure; Lysozyme; Meat - microbiology; Membrane Potentials - drug effects; Microbial Sensitivity Tests; Microscopy, Electron, Scanning - methods; Muramidase - pharmacology; Nisin; Nisin - pharmacology; Osmolar Concentration; Time Factors; Nisin; Lactic acid bacteria; Food spoilage; Lysozyme; Enzyme; Lactobacillus curvatus; Foodstuff; Synergism; Glycosidases; Pathogenic; Minimum inhibitory concentration; Bacteria; Hydrolases; Lactobacillaceae; Micrococcales; Micrococcaceae; Antibacterial agent; Mechanism of action; O-Glycosidases; Biological contamination; Staphylococcus aureus
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/S0168-1605(00)00330-5

Lysozyme was formulated together with nisin for usage against food spoilage lactobacilli. The mixtures demonstrated improved minimal inhibitory concentrations (MIC), compared to the parent compounds, for many of the bacteria and media tested, including high salt media in which lysozyme lost virtually all of its activity. Synergy was also observed through measurement of the kinetics of bacterial killing of
L. curvatus 845, in which strain synergy had been observed in MIC assays. The combination of lysozyme and nisin caused more severe cell damage as viewed by scanning electron microscopy, and a consequent change in optical density at 600 nm, compared to the parent compounds, effects that were presumed to reflect the action of lysozyme. In addition, the combination caused more rapid permeabilization (depolarization) of the cytoplasmic membranes of
Staphylococcus aureus, an effect that reflected the mechanism of action of nisin. Thus, nisin and lysozyme appear to demonstrate synergy against gram-positive bacteria because they reinforce each others mechanisms of bacterial killing.