Safety Evaluation and Antibacterial Activity of Enterococci Isolated from Lighvan Cheese

Abstract

Twenty three enterococci were isolated from Lighvan cheese. Enterococcal isolates identified by 16S rDNA sequencing, were evaluated for their safety and also examined for antibacterial activity and presence of the genes coding for enterocins. Four enterococcal isolates exhibited inhibitory activity against Listeria innocua and E. faecalis and harbored the bacteriocin genes (enterocins A, B, P, X and 31) too. Multiple combinations of virulence determinant genes (vanA, vanB, gelE, esp, asa1, cpd and ace) were detected in enterococcal isolates with the exception of 5 E. faecium isolates. While the isolates exhibited resistance to some antibiotics, all of them were susceptible to ampicillin and vancomycin. In conclusion, this study shows the presence of enterococci with potential biopreservative activity in Lighvan cheese; however it also warrants further research on the safety and origins of enterococci in this cheese. Practical Applications Lighvan is a very popular cheese in Iran with a specific texture and taste which is produced in little amount from raw sheep milk and ripened in manmade underground galleries. There are a few studies about the microflora of this cheese and the point is that enterococcus species have proven to be always dominant. Safety evaluation of these bacteria is really necessary as far as the Lighvan cheese is produced from raw milk and also the controversial viewpoint that there is about the GRAS state of enterococcus species. Recognition of the safe strains of enterococcus species isolated from the lighvan cheese would help to produce a more hygienic and safer industrial product.

Evaluation of the Functional Properties and Safety of Enterocin-producing Enterococcus faecium BT29.11 Isolated from Turkish Beyaz Cheese and its Inhibitory Activity against Listeria monocytogenes in UHT Whole Milk

“…As a result of PCR analysis, three PCR bands were detected in E. faecium BT29.11 strain: 126 bp with entA (Figure 4, line 1), 162 bp with entB (Figure 4, line 2) as expected, and 450 bp with entX (Figure 4, line 5), instead of the expected 500 bp. The presence of entA, entB, and entX has been found together in E. faecium strains isolated from Turkish Tulum and Beyaz cheeses (Avcı and Özden Tuncer, 2017), Lingvan cheese (Joghataei et al, 2017), and boza (Gök Charyyev et al, 2019), as confirmed in this study. These data suggest that strain BT29.11 might express more than one enterocin.…”

Prevalence of Virulence Genes and Antibiotic Resistance Pattern in Enterococcus Faecalis Isolated from Urinary Tract Infection in Shahrekord, Iran

“…In the study of Joghatei et al, resistance to erythromycin, tetracycline and ciprofloxacin was 40%, 20% and 8% respectively. While in our study the resistance tetracycline, erythromycin, and norfloxacin was reported to 83.33%, 46.67% and 30% (35). Resistance to the antibiotics mentioned in our study is higher than that of Joghatei et al, Aminoglycosides are still valuable in the treatment of bacterial infections, despite their side effects and problems associated with increased resistance of microorganisms to these drugs.…”

“…The protein of the aggregate that carries the asa1 gene in enterococci is produced in response to sex pheromones that cause these bacteria to be absorbed into each other and form a cell mass. It also plays an important role in stimulating adhesion, invading cells and destroying myocardial and lung tissues (33)(34)(35).…”

Evaluation of bacterial and fungal communities during the fermentation of Baixi sufu, a traditional spicy fermented bean curd

“…In the current study, Enterococci members were the predominant LAB, and correlation analyses revealed a positive link between Enterococci and amino nitrogen, suggesting that enterococcus may contribute to proteolysis in the pre‐fermentation of BS. Despite some authors considering that enterococcus may have virulence genes, related to common human pathogens, many researchers have found that enterococci exist widely in fermented foods, which are contributing factors to flavor formation and bioprotection.…”