title: Nisin-bacteriophage crossresistance in Staphylococcus aureus.
abstract: The combined effect of nisin and two lytic phages against Staphylococcus aureus was assessed. In short-time challenge experiments performed in pasteurized milk, a synergistic effect was observed. However, the development of nisin-adapted cells seriously compromised bacteriophage activity. A nisin-adapted strain became partially resistant to both phages. Efficiency of plaquing as well as adsorption values differed. Changes on the bacterial surface, often linked to nisin resistance, could account for the phenotypes observed, most likely by interfering with binding/recognition of phage receptors. The nisin-adapted strain was significantly less hydrophobic and with a higher positive net charge as shown by the lack of binding of cytochrome c and nisin. Loss of the nisin resistant phenotype restored phage susceptibility. In contrast, bacteriophage insensitive mutants were not nisin resistant. The results indicate that careful use of nisin and bacteriophages in combination is required for control of S. aureus in dairy products.
authors.affiliation: Instituto de Productos Lácteos de Asturias (IPLA-CSIC). Apdo. 85. 33300- Villaviciosa, Asturias, Spain.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Martínez
authors.forename: Jose María
authors.initials: JM
authors.lastname: Obeso
authors.forename: Ana
authors.initials: A
authors.lastname: Rodríguez
authors.forename: Pilar
authors.initials: P
authors.lastname: García
mesh_terms: D000818:Animals; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D004305:Dose-Response Relationship, Drug; D024881:Drug Resistance, Bacterial; D004357:Drug Synergism; D005516:Food Microbiology; D005520:Food Preservatives / Q000494:pharmacology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D008892:Milk / Q000382:microbiology*; D009154:Mutation; D009561:Nisin / Q000494:pharmacology*; D013202:Staphylococcal Food Poisoning / Q000517:prevention & control*; D013204:Staphylococcus Phages; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000254:growth & development
chemical_list: D005520:Food Preservatives; D009561:Nisin