Potassium Chloride, Sodium Lactate and Sodium Citrate Impaired the Antimicrobial Resistance and Virulence of NT06 Isolated from Fish.

Sodium chloride (NaCl) is a commonly used additive in minimally processed fish-based products. The addition of NaCl to fish products and packaging in a modified atmosphere is usually efficient with regard to limiting the occurrence of the aquatic environmental pathogen Given the negative effects of excess NaCl in the diet, there is a growing demand to reduce NaCl in food products with safer substituents, but the knowledge of their impact on antibiotic resistant is limited. This study aimed to evaluate the physiological and transcriptome characteristics of NT06 isolated from fish and to determine the effect of selected concentrations of alternative NaCl compounds (KCl/NaL/NaC) on the NT06 virulence phenotype and genotype. In the study, among the isolated microorganisms, NT06 showed the highest antibiotic resistance (to ampicillin, ceftriaxone, nalidixic acid, and norfloxacin) and the ability to grow at 4 °C. The Comprehensive Antibiotic Resistance Database (CARD) and the Virulence Factor Database (VFDB) revealed the presence of 24 and 134 gene products assigned to AMR and VF in the NT06 transcriptome, respectively. KCl, KCl/NaL and KCl/NaL/NaC inhibited pyocyanin biosynthesis, elastase activity, and protease activity from 40 to 77%. The above virulence phenotypic observations were confirmed via RT-qPCR analyses, which showed that all tested AMR and VF genes were the most downregulated due to KCl/NaL/NaC treatment. In conclusion, this study provides insight into the potential AMR and VF among foodborne and the possible impairment of those features by KCl, NaL, and NaC, which exert synergistic effects and can be used in minimally processed fish-based products.