Evaluation of resistance genes and virulence factors in a food isolated Enterococcus durans with potential probiotic effect

Enterococci belong to the lactic acid bacteria (LAB) group, which are often considered to provide benefit to the host organism when consumed. However, these microorganisms have a potential as infective agents, being necessary to evaluate the presence of virulence factors and resistance to antibiotics to warrant the safe use of new strains as probiotic cultures. This study aimed to detect genes of potential virulence factors related with adhesion, aggregation, biofilm formation and resistance to vancomycin, in addition to evaluate the antibiotic susceptibility and adhesion capacity of Enterococcus durans LA18s, a strain previously isolated from Minas Frescal cheese. The PCR reactions with specific primers to detect genes of adhesion collagen protein (ace), aggregation substances (agg and asa), bopA (putative glycosyltransferase), bopB (beta-phosphoglucomutase), bopC (aldose 1-epimerase), and bopD (sugar-binding transcriptional regulator) were negative for E. durans LAB18s. In addition, the strain did not present the resistance genes vanA, vanC1 and vanC2/3, and exhibited sensibility to antibiotics commonly used in animal feed, such as erythromycin, tetracycline, vancomycin, gentamicin and penicillin. This strain also showed a strong capacity of biofilm formation and exhibited satisfactory auto-aggregative and hydrophobicity features. The results suggest that this strain can be safely used in animal feed.