Safety and technological properties of bacteriocinogenic enterococci isolates from Tunisia

Abstract

This is one of very few studies that identified safe Enterococcus strains capable of producing a wide variety of enterocins against different spoilage and pathogenic micro-organisms that have good potential for application as adjunct/protective cultures in foods.

Screening probiotic strains for safety: Evaluation of virulence and antimicrobial susceptibility of enterococci from healthy Chinese infants

“…Three isolates showed hemolytic activity but were cylA-free. Jaouani et al (2015) reported similar results and speculated that other lytic genes might be involved in the cytolysin expression.…”

“…Interestingly, 4 gelE-positive strains did not show gelatinase activity, and 4 clyA-positive strains did not show hemolytic activity. The silence of clyA and gelE has been reported frequently (Medeiros et al, 2014;Jaouani et al, 2015). Perin et al (2014) reported that different culture conditions could strongly influence the expression of clyA and gelE.…”

“…Cytolysin is an exotoxin resulting in hemolysis and evasion by pathogens from attack by the host immune system (Moraes et al, 2012). Gelatinase hydrolyses gelatin, collagen, and certain bioactive peptides, and it is involved in the initiation and propagation of inflammatory processes from enterococci, which might cause endocarditis (Jaouani et al, 2015). In our investigation, 36.8% of the strains exhibited positive hemolytic activity (3 with α-hemolysis and 11 with β-hemolysis) and 17.5% were positive for the production of gelatinase.…”

“…The vancomycin gene consists of varies types (e.g., vanA, vanB, vanC, and vanD). We chose vanA and vanB for genotype analysis, because they are normally harbored on plasmids, resulting in horizontal gene transfer and spread of antimicrobial resistance in the host (Jaouani et al, 2015). We found that none of isolates carried vanA or vanB genes, and only 3 isolates (E. faecalis WEFA03, WEFA16, WEFA20) were resistant to vancomycin, indicating that other resistance types (e.g., vanC, vanD, vanE, or vanG) must be present.…”

Assessment of food safety using a new real-time PCR assay for detection and quantification of virulence factors of enterococci in food samples

“…For instance, in a recent study, Jaouani et al . () identified safe Enterococcus strains with suitable technological properties that can produce a wide variety of enterocins against pathogenic micro‐organisms. Moreover, many types of raw milk cheeses are still eaten fresh in many countries all over the world, such as ricotta, chevre, quark, cottage, queso fresco, Egyptian karish cheese and other Mexican‐style fresh cheeses (Hammed et al .…”