Abstract The antimicrobial activity of gold and silver nanoparticles (AuNPs, AgNPs), chitosan (CS) and their combinations was established by determining the minimum inhibitory concentration for planktonic (MICPC80) and biofilm growth (MICBC80), for biofilm formation (MICBF80), metabolic activity (MICBM80) and reduction (MICBR80), and for the metabolic activity of preformed biofilm (MICMPB80). Biofilms were quantified in microtitre plates by crystal violet staining and metabolic activity was evaluated by the MTT assay. Chitosan effectively suppressed biofilm formation (0.31–5 mg ml−1) in all the tested strains, except Salmonella enterica Infantis (0.16–2.5 mg ml−1) where CS and its combination with AgNPs induced biofilm formation. Nanoparticles inhibited biofilm growth only when the highest concentrations were used. Even though AuNPs, AgNPs and CS were not able to remove biofilm mass, they reduced its metabolic activity by at least 80%. The combinations of nanoparticles with CS did not show any significant positive synergistic effect on the tested target properties.

中文翻译：

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金银纳米粒子、壳聚糖及其组合对食源性病原体细菌生物膜的影响

摘要 通过确定浮游生物 (MICPC80) 和生物膜生长 (MICBC80)、生物膜形成 (MICBF80)、代谢的最小抑制浓度，确定金和银纳米粒子 (AuNPs、AgNPs)、壳聚糖 (CS) 及其组合的抗菌活性。活性（MICBM80）和还原（MICBR80），以及预形成生物膜的代谢活性（MICMPB80）。通过结晶紫染色在微量滴定板中量化生物膜，并通过 MTT 测定评估代谢活性。壳聚糖在所有测试菌株中有效抑制生物膜形成（0.31-5 mg ml-1），除了婴儿沙门氏菌（0.16-2.5 mg ml-1），其中 CS 及其与 AgNPs 的组合诱导生物膜形成。纳米颗粒仅在使用最高浓度时才抑制生物膜生长。尽管 AuNPs，AgNPs 和 CS 无法去除生物膜质量，它们将其代谢活性降低了至少 80%。纳米颗粒与 CS 的组合对测试的目标特性没有表现出任何显着的积极协同效应。