Use of bacteriocinogenic lactic acid bacteria to inhibit spontaneous nisin-resistant mutants of Listeria monocytogenes Scott A.
Nisin is a bacteriocin with a broad antibacterial spectrum including strains of Listeria monocytogenes. Populations of L. monocytogenes, however, frequently contain spontaneous nisin-resistant mutants. When a culture of L. monocytogenes Scott A was exposed to nisin concentrations between 10 and 500 IU ml-1, the initial decrease in viable numbers was followed by regrowth of survivors to nisin. Nisin-resistant mutants of L. monocytogenes Scott A were isolated after a single exposure to nisin at 100 IU ml-1 and were shown to be sensitive to the non-nisin bacteriocins, sakacin A and enterocin B, produced by Lactobacillus sake Lb 706 and Enterococcus faecium BFE 900, respectively. The regrowth of L. monocytogenes Scott A following the initial decrease due to exposure to nisin was prevented by nisin-resistant Lact. sake Lb 706-la and to a somewhat lesser extent, by Ent. faecium BFE 900-6a. Listerial cells surviving nisin action were thus inhibited by the bacteriocin-producing strains that might be used as starter or protective cultures in foods. Growth of a nisin-resistant mutant of L. monocytogenes Scott A (Li3) was also suppressed by the bacteriocinogenic cultures. Use of nisin in combination with a starter culture producing a non-nisin antilisterial bacteriocin may therefore prevent the emergence of nisin-resistant mutants of L. monocytogenes.
Schillinger
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U
Institut für Hygiene und Toxikologie, Bundesforschungsanstalt für Ernährung, Karlsruhe, Germany. Ulrich.schillinger@bfe.uni-karlsruhe.de
Chung
H S
HS
Keppler
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K
Holzapfel
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WH
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000898:Antibiosis; D001430:Bacteriocins / Q000302:isolation & purification / Q000494:pharmacology*; D004352:Drug Resistance, Microbial / Q000235:genetics; D016984:Enterococcus faecium / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D007778:Lactobacillus / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D008089:Listeria monocytogenes / Q000187:drug effects / Q000235:genetics / Q000254:growth & development*; D008826:Microbial Sensitivity Tests; D009561:Nisin / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D001430:Bacteriocins; C107801:enterocin B; C071456:sakacin A; D009561:Nisin