Effect of sub-lethal chemical disinfection on the biofilm forming ability, resistance to antibiotics and expression of virulence genes of Salmonella Enteritidis biofilm-surviving cells

• Published in: Biofouling (Chur, Switzerland) Switzerland), 2020, Vol.36 (1), p.101-112
• Main Authors: Romeu, Maria João, Rodrigues, Diana, Azeredo, Joana
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents - pharmacology; Antibiotic resistance; Antibiotics; Antiseptics; Bacteria; Benzalkonium chloride; Benzalkonium Compounds - pharmacology; biofilm; Biofilms; Biofilms - drug effects; Biofilms - growth & development; Cells; chemical disinfectants; cross-resistance; Disease resistance; Disinfectants; Disinfectants - pharmacology; Disinfection; Disinfection & disinfectants; Disinfection - methods; Drug resistance; Drug Resistance, Bacterial - drug effects; Drug Resistance, Bacterial - genetics; Exposure; Food; Foodborne pathogens; Foods; Gene expression; Gene Expression - drug effects; Genes; Genes, Bacterial - drug effects; Health risks; Hydrogen peroxide; Organic chemistry; Procedures; Salmonella; Salmonella Enteritidis; Salmonella enteritidis - drug effects; Salmonella enteritidis - genetics; Salmonella enteritidis - growth & development; Salmonella enteritidis - pathogenicity; Sodium; Sodium hypochlorite; Sodium Hypochlorite - pharmacology; Survival; Virulence; Virulence - drug effects; Virulence - genetics
• ISSN: 0892-7014; 1029-2454
• DOI: 10.1080/08927014.2020.1719077

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.