faecium, which is in concordance with previous reports [32–34]. In this respect, most of the E. faecalis (95%) and a large percentage of the E. faecium (53%) strains evaluated in this work showed, at least, one virulence factor, being efaAfs, gelE and agg the most frequently detected genes. With regard to gelE, which
encodes for an extracellular zinc selleck endopeptidase that hydrolyzes gelatin, collagen, hemoglobin, and other bioactive compounds, this gene was detected at high frequency in E. faecalis, with all the gelE + strains showing gelatinase activity. However, five out of nine E. faecium strains harbouring gelE were unable to degrade gelatin, suggesting the MAPK inhibitor carriage of a non-functional gene, as previously reported [32, 33]. Likewise, in the case of E. faecium P68 and E. faecium GM29 harbouring cylL L cylL S , the lack of hemolytic activity may be explained by the absence of cylM, whose product is involved in the post-translational modification of cytolysin. On the other hand, esp and hyl, which encode a cell wall-associated
protein involved in immune evasion and an hyaluronidase enzyme, respectively, were not found in any of the tested LAB. Previous studies have reported that esp and hyl are more common in ampicillin-resistant/vancomycin-resistant E. faecium (VREF) than in ampicillin-susceptible/VREF strains . In this context, the increase in the incidence of VREF at hospital settings has been attributed mainly to the spread of ampicillin-resistant VREF exhibiting esp and/or hyl[36, 37]. Therefore, check details the fact that the E. faecium strains evaluated in this work lack these genes might be related with their non-clinical origin and absence of ampicillin resistance. The use and frequent overuse of antibiotics, Celecoxib including those used in human medicine, in fish farming has resulted in the emergence and spread of antibiotic-resistant bacteria in the aquaculture environment. This possesses a threat to human and animal health due to the increase
of acquired antibiotic resistance in fish pathogens, the transfer of their genetic determinants to bacteria of terrestrial animals and to human pathogens, and the alterations of the bacterial microbiota of the aquatic environment [11, 29]. In our study, the percentage of enterococcal strains showing acquired antibiotic resistance was 68%. Interestingly, the results found in E. faecium (71%) and E. faecalis (62%) were similar, however, higher percentages of resistance to ciprofloxacin and/or norfloxacin, rifampicin, and glycopeptides were observed in E. faecalis. Nevertheless, the occurrence of erythromycin and tetracycline resistance was frequently detected amongst E. faecium (45%) but only in one E. faecalis strain (5%). In spite of the high prevalence of acquired antibiotic resistance found in enterococci of aquatic origin, they showed low incidence or absence of resistance to the clinically relevant antibiotics vancomycin (8.