Probiotic Weissella cibaria displays antibacterial and anti-biofilm effect against cavity-causing Streptococcus mutans.

Streptococcus mutans is a significant contributor to dental caries and causes functional and aesthetic discomfort. Weissella cibaria strains were isolated from kimchi, and their functional properties were determined. In this study, the antibacterial and antibiofilm effects of four W. cibaria strains (D29, D30, D31, and B22) were evaluated against three S. mutans strains using culture fluid and cell-free supernatants. The results showed that W. cibaria reduced the exopolysaccharides production and auto-aggregation, increased co-aggregation, and downregulated virulence factors, leading to the inhibition of bacterial growth and biofilm formation. These findings were confirmed using scanning electron microscopy and confocal laser scanning microscopy. These results indicate that oral health can be potentially improved by W. cibaria.

Synergistic antimicrobial activity of ε-polylysine, chestnut extract, and cinnamon extract against Staphylococcus aureus.

A mixed natural preservative composed of ε-polylysine (ε-PL), chestnut 70% ethanol extract (NE), and cinnamon hydrothermal extract (CW), was investigated for the reduction of Staphylococcus aureus. The minimum inhibitory concentration (MIC) and minimum bacterial concentration (MBC) of seven natural extracts were investigated against a cocktail of three strains of S. aureus (ATCC 25923, ATCC 33591, and ATCC 33594). Three important factors (ε-PL, NE, and CW) were selected by using the Plackett-Burman (PB) design for the response surface model (P < 0.001). Following a central composite design, S. aureus were treated with mixtures of natural preservatives that included ε-PL, NE, and CW. The MIC and MBC of ε-PL and the natural extracts and ranged from 1 to 16 mg/mL (R2 = 0.9857). The mixed natural preservative presented a synergistic antibacterial effect, at the optimum point. These results suggest that mixed natural preservatives of ε-PL, NE, and CW can lower the economic cost of food processing.

Antimicrobial and Antibiofilm Effect of ε-Polylysine against Salmonella Enteritidis, Listeria monocytogenes, and Escherichia coli in Tryptic Soy Broth and Chicken Juice.

ε-Polylysine (ε-PL) is a safe food additive that is used in the food industry globally. This study evaluated the antimicrobial and antibiofilm activity of antibacterial peptides (ε-PL) against food poisoning pathogens detected in chicken (Salmonella Enteritidis, Listeria monocytogenes, and Escherichia coli). The results showed that minimum inhibitory concentrations (MICs) ranged between 0.031-1.0 mg/mL, although most bacterial groups (75%) showed MICs of 1.0 mg/mL. The reduction in the cell viability of pathogens due to ε-PL depended on the time and concentration, and 1/2 × MIC of ε-PL killed 99.99% of pathogens after 10 h of incubation. To confirm biofilm inhibition and degradation effects, crystal violet assay and confocal laser scanning microscopy (CLSM) were used. The biofilm formation rates of four bacterial groups (Salmonella, Listeria, E. coli, and multi-species bacteria) were 10.36%, 9.10%, 17.44%, and 21.37% at 1/2 × MIC of ε-PL, respectively. Additionally, when observed under a CLSM, ε-PL was found to induce biofilm destruction and bacterial cytotoxicity. These results demonstrated that ε-PL has the potential to be used as an antibiotic and antibiofilm material for chicken meat processing.

Anti-Biofilm Activity of Cell-Free Supernatant of Saccharomyces cerevisiae against Staphylococcus aureus.

Staphylococcus aureus is one of the most common microorganisms and causes foodborne diseases. In particular, biofilm-forming S. aureus is more resistant to antimicrobial agents and sanitizing treatments than planktonic cells. Therefore, this study aimed to investigate the anti-biofilm effects of cell-free supernatant (CFS) of Saccharomyces cerevisiae isolated from cucumber jangajji compared to grapefruit seed extract (GSE). CFS and GSE inhibited and degraded S. aureus biofilms. The adhesion ability, auto-aggregation, and exopolysaccharide production of CFS-treated S. aureus, compared to those of the control, were significantly decreased. Moreover, biofilm-related gene expression was altered upon CFS treatment. Scanning electron microscopy images confirmed that CFS exerted anti-biofilm effects against S. aureus. Therefore, these results suggest that S. cerevisiae CFS has anti-biofilm potential against S. aureus strains.

Application of mixed natural preservatives to improve the quality of vacuum skin packaged beef during refrigerated storage.

This study aimed to develop an active packaging (AP) system for beef storage using vacuum skin packaging (VSP) applied with mixed natural preservatives (MNPs) consisting of grapefruit seed extract (GSE), cinnamaldehyde (CA), and nisin; and to assess its effect on the physicochemical, microbial, and antibacterial properties against food-borne pathogens in beef compared with using wrapped packaging (WP) and VSP. The pH of the AP was a medium level of WP and VSP. AP was effective in preserving beef surface color including lightness and redness. AP delayed lipid oxidation and protein deterioration of beef by 14 days and 7 days as compared to that in WP and VSP, respectively. It also slowed low microbial counts of psychrotrophic and anaerobic bacteria about 1-2 Log CFU/g and inhibited the growth of experimented food-borne pathogens compared to initial inoculated counts. Our results indicated that MNPs applied to AP could be used to extend the shelf life of beef and prevent related food poisoning.

Effects of roxithromycin on the pharmacokinetics of loratadine after oral and intravenous administration of loratadine in rats.

The present study aimed to investigate the effect of roxithromycin on the oral and intravenous pharmacokinetics of loratadine in rats. The pharmacokinetic parameters ofloratadine were measured after an orally (4 mg/kg) and intravenously (1 mg/kg) administration of loratadine in the presence or absence of roxithromycin (2.0 or 5.0 mg/kg). Compared with the control (given loratadine alone), the area under the plasma concentration-time curve (AUC) was significantly (2.0 mg/kg, P < 0.05; 5.0 mg/kg, P < 0.01) increased by (76.8-119.2)% in the presence of roxithromycin after oral administration of loratadine. The peak plasma concentration (Cmax) was significantly (2.0 mg/kg, P < 0.05; 5.0 mg/kg, P < 0.01) increased by (45.1-97.6)% in the presence of roxithromycin after oral administration of loratadine. Consequently, the relative bioavailability (R.B.) of loratadine was increased by 1.77- to 2.19-fold. In contrast, roxithromycin had no effect on any pharmacokinetic parameters of loratadine given intravenously. It suggested that roxithromycin may improve the oral bioavailability of loratadine by reducing first-pass metabolism of loratadine most likely mediated by P-glycoprotein (P-gp) and/or cytochrome P450 (CYP) 3A4 in the intestine and/or liver. In conclusion, the presence of roxithromycin significantly enhanced the bioavailability of loratadine in rats, it may be due to inhibition of both CYP 3A4-mediated metabolism and P-gp in the intestine and/or liver by the presence of roxithromycin.