Abstract Although disinfection procedures are widely implemented in food environments, bacteria can survive and present increased virulence/resistance. Since little is known about these phenomena regarding biofilms, this study aimed to investigate the effect of chemical disinfection on biofilm-derived cells of Salmonella Enteritidis. Using a reference strain (NCTC 13349) and a food isolate (350), biofilm susceptibility to benzalkonium chloride (BAC), sodium hypochlorite (SH) and hydrogen peroxide (HP) was evaluated and biofilms were exposed to sub-lethal concentrations of each disinfectant. Biofilm-derived cells were characterized for their biofilm forming ability, antibiotic resistance and expression of virulence-associated genes. Except for a few instances, disinfectant exposure did not alter antibiotic susceptibility. However, SH and HP exposure enhanced the biofilm forming ability of Salmonella Enteritidis NCTC 13349. After BAC and HP exposure, biofilm-derived cells presented a down-regulation of rpoS. Exposure to BAC also revealed an up-regulation of invA, avrA and csgD on Salmonella Enteritidis NCTC 13349. The results obtained suggest that biofilm-derived cells that survive disinfection may represent an increased health risk.

中文翻译：

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亚致死化学消毒对肠炎沙门氏菌生物膜存活细胞生物膜形成能力、抗生素耐药性及毒力基因表达的影响

摘要 虽然消毒程序在食品环境中广泛实施，但细菌可以存活并呈现出更高的毒力/抗性。由于对生物膜的这些现象知之甚少，本研究旨在研究化学消毒对肠炎沙门氏菌生物膜衍生细胞的影响。使用参考菌株 (NCTC 13349) 和食品分离株 (350)，评估了生物膜对苯扎氯铵 (BAC)、次氯酸钠 (SH) 和过氧化氢 (HP) 的敏感性，并将生物膜暴露于每种消毒剂的亚致死浓度. 生物膜衍生细胞的特征在于它们的生物膜形成能力、抗生素抗性和毒力相关基因的表达。除了少数情况外，接触消毒剂并没有改变抗生素敏感性。然而，SH 和 HP 暴露增强了肠炎沙门氏菌 NCTC 13349 的生物膜形成能力。 BAC 和 HP 暴露后，生物膜衍生细胞呈现 rpoS 的下调。暴露于 BAC 还揭示了肠炎沙门氏菌 NCTC 13349 上 invA、avrA 和 csgD 的上调。获得的结果表明，在消毒后存活的生物膜衍生细胞可能代表增加的健康风险。