Enterococcus faecium and Enterococcus durans isolated from cheese: Survival in the presence of medications under simulated gastrointestinal conditions and adhesion properties

Abstract

In this study, we evaluated the survival of Enterococcus faecium and Enterococcus durans, isolated from cheese, in the presence of medications and under simulated in vitro gastrointestinal conditions. The presence of genes encoding virulence factors, the susceptibility to antimicrobial agents, and adhesion properties were also assessed. Enterococcus faecium and E. durans both exhibited resistance to most of the tested medications but showed a large sensitivity to analgesics and antihypertensives; they also showed wide susceptibility to antimicrobial agents. Enterococcus durans SJRP29 had greater resistance to the presence of medications in comparison with the probiotic Lactobacillus acidophilus La-5. The strains, except for E. durans SJRP05, did not harbor virulence genes. Enterococcus durans SJRP14, SJRP17, and SJRP26 were sensitive to all tested antimicrobial agents. Enterococcus faecium was more stable during the simulation of gastrointestinal tract and showed greater viability. At the end of the assay, except for E. durans SJRP17, all strains showed high viability (>7 log cfu/mL). Enterococcus durans SJRP29 stood out from the other strains and was selected for further evaluation; it tolerated up to 3.0% NaCl at 30 and 37°C, besides having good adhesion properties (high values of auto-aggregation, co-aggregation, and hydrophobicity). Additionally, the microorganism did not show bile salt hydrolase activity or mucin degradation. These results encourage carrying out additional tests to evaluate the probiotic features by using in vitro dynamic models and in vivo tests before applying these strains to a food system.

Short communication: Antimicrobial resistance and virulence genes of Enterococcus faecalis isolated from subclinical bovine mastitis cases in China

“…Resistance genes of erythromycin (ermA, ermB, and ermC) and tetracycline (tetK, tetL, tetM, tetO, and tetS), as well as virulence genes gelE (gelatinase), hyl (hyaluronidase), asa1 (aggregation substance), esp (enterococcal surface protein), cylA (cytolysin), efaA (en-docarditis-specific antigen), and ace (collagen binding cell wall protein) were detected by PCR amplification with specific primers as described previously (Petersen and Dalsgaard, 2003;Amaral et al, 2017). Overall, 81 (4.5%) E. faecalis isolates were detected from 1,787 mastitic milk samples.…”

Selection of autolytic lactic acid bacteria as potential adjunct cultures to accelerate ripening of white-brined cheeses

“…The identification of E. faecium as high autolytic activity in both raw milk and white-brined cheese was in good agreement with microflora studies previously on these food samples. This is especially the case for Enterococcus spp., which can tolerate high salt concentrations (Amaral et al, 2017;Karabey et al, 2018). Recent studies have The effect of different pH values, salt concentrations and carbon sources on the autolytic behavior of 10 LAB strains was determined under conditions similar to the production of whitebrined cheese.…”

Strains of lactic acid bacteria isolated from traditional Carpathian cheeses

“…The most common species of Enterococcus isolated from the cheese were the following species: E. faecium, E. faecalis and E. durans (Belicov et al, 2007;Serio et al, 2007;Veljovic et al, 2007). Some E. faecium strains manifest probiotic properties (Saarela et al, 2000;Ammor et al, 2007;Franz et al, 2011;Amaral et al, 2016).…”

“…These features, first of all, include safety, i.e. no pathogenic factors and no signs of resistance to antibiotics (Amaral et al, 2016;Zhang et al, 2016). Some features of the strains are related to the probiotic properties, i.e.…”

“…Some features of the strains are related to the probiotic properties, i.e. ability to synthesize the bacteriocins (Ao et al, 2012;Goh & Philip, 2015), survival in the conditions of the gastrointestinal tract and manifestation of adhesive properties (Amaral et al, 2016) and decrease in the level of cholesterol in the blood (Zhang et al, 2017). The objective of our research was the isolation and identification of LAB in traditional Carpathian cheese, made of sheep milk, and study of their properties.…”