Effect of NaCl on Heat Resistance, Antibiotic Susceptibility, and Caco-2 Cell Invasion ofSalmonella

Abstract

This study evaluated the effects of NaCl on heat resistance, antibiotic susceptibility, and Caco-2 cell invasion of Salmonella. Salmonella typhimurium NCCP10812 and Salmonella enteritidis NCCP12243 were exposed to 0, 2, and 4% NaCl and to sequential increase of NaCl concentrations from 0 to 4% NaCl for 24 h at 35°C. The strains were then investigated for heat resistance (60°C), antibiotic susceptibility to eight antibiotics, and Caco-2 cell invasion efficiency. S. typhimurium NCCP10812 showed increased thermal resistance (P < 0.05) after exposure to single NaCl concentrations. A sequential increase of NaCl concentration decreased (P < 0.05) the antibiotic sensitivities of S. typhimurium NCCP10812 to chloramphenicol, gentamicin, and oxytetracycline. NaCl exposure also increased (P < 0.05) Caco-2 cell invasion efficiency of S. enteritidis NCCP12243. These results indicate that NaCl in food may cause increased thermal resistance, cell invasion efficiency, and antibiotic resistance of Salmonella.

Comparison of growth and disinfectant resistance of Bacillus cereus isolated from fresh-cut produce and organic vegetables

“…At 25, 30, and 35 o C, no significant (p>0.05) differences were observed between strains with respect to growth (data not shown). Different growth patterns among B. cereus strains may be caused by strain variations between the bacteria (14,15).…”

Effects of sodium chloride on heat resistance, oxidative susceptibility, motility, biofilm and plaque formation of Burkholderia pseudomallei

“…Our present study verified that the growth rate of six (Volker, Mach, Schmid, & Hecker, 1992), and Escherichia coli (Gunasekera, Csonka, & Paliy, 2008), have also reported that activation of the salt stress response conferred cross-protection against other stresses, that is, increased resistance to heat and H 2 O 2 . Recently, Yuan, Agoston, Lee, Lee, & Yuk, (2012) and Yoon et al, (2013) also showed that the heat resistance of Salmonella enterica was increased after exposure to NaCl. Moreover, it is evident that growing Vibrio harveyi in LB broth supplemented with 2% NaCl (34.2 mmol L −1 ) resulted in increased resistance to menadione killing compared with the same organism grown in normal LB broth (Vattanaviboon, Panmanee, & Mongkolsuk, 2003).…”

“…Several studies have shown that exposure to NaCl can influence the adaptive survival and virulence of pathogenic bacteria. The relevance of this has been shown in Salmonella enterica serovar Typhimurium (12) , Staphylococcus aureus (Park et al., ), and Listeria monocytogenes (Garner, James, Callahan, Wiedmann, & Boor, ), whereby bacteria cultured in medium‐containing high NaCl show increased heat tolerance (Park et al., ; Yoon, Park, Oh, Choi, & Yoon, ), antibiotic resistance (Yoon et al., ), and invasion ability into host cells (Garner et al., ; Yoon et al., ). Our previous study also showed that B. pseudomallei grown under salt stress displayed significantly greater resistance to the antibiotic ceftazidime (Pumirat et al., ).…”

The Correlation between NaCl Adaptation and Heat Sensitivity of Listeria monocytogenes, a Foodborne Pathogen through Fresh and Processed Meat

“…In addition, NaCl-exposed E. coli O157:H7 NCCP11142 was heat resistant, and could survive at 50℃ ( Lee et al , 2015 ). Also, Yoon et al (2013) showed that heat resistance in Salmonella Typhimurium exposed to high NaCl concentration was increased.…”

“…To identify the invasive capability of L. monocytogenes , invasion assay using various human epithelial cell lines was usually performed, and the invasion efficiency was influenced by several stresses ( Garner et al , 2006 ; Lee et al , 2013 ). Yoon et al (2013) demonstrated that S . Typhimurium exposed to high NaCl concentration increased invasion efficiency into Caco-2 cells.…”