Virulence factor genes possessing Enterococcus faecalis strains from rabbits and their sensitivity to enterocins

[EN] Information concerning the virulence factor genes and antibiotic resistance of rabbit enterococci is limited, so in this study we tested the virulence factor genes in Enterococcus faecalis strains from rabbits. Moreover, their resistance/sensitivity to antibiotics and sensitivity to enterocins was also tested, with the aim of contributing to our enterocin spectra study and to indicate the possibility of enterocin application in prevention or contaminant elimination in rabbit husbandry. A total of 144 rabbit samples were treated using a standard microbiological method. Thirty-one pure colonies of the species Enterococcus faecalis were identified, using the MALDI-TOF identification system and confirmed using phenotyping, among which 15 strains were virulence factor gene absent. The gelE gene was the most detected (42%); however, the expression of gelatinase phenotype did not always correlate with the detection of gelE. Strains did not show ß-haemolysis and were mostly resistant to tested antibiotics, but sensitive to enterocins (Ent), mainly to Ents EK13=A (P), 2019 and Ent M. Rabbit E. faecalis strains displayed antibiotic resistant traits and the presence of expressed and silent virulence genes, but they showed high levels of sensitivity to natural antimicrobials-enterocins, which indicates the possible prevention of multidrug and virulent enterococcal contaminants by enterocins.This study was supported by Project 2/0004/14 and 2/0006/17. The care and experimental procedures with animals followed the guidelines stated in the Guide for the Care and Use of Laboratory Animals (1996) and the trials were accepted by the Ethical Commission of the Institute of Animal Physiology in Košice and by the Slovak Veterinary and Food Administration. We are grateful to Ľubica Chrastinová from the National Agricultural and Food Centre, Nitra for her skillful assistance and sampling.Pogány Simonová, M.; Lauková, A. (2017). Virulence factor genes possessing Enterococcus faecalis strains from rabbits and their sensitivity to enterocins. World Rabbit Science. 25(1):63-71. https://doi.org/10.4995/wrs.2017.5694SWORD637125

Effect of Bacteriocin-Like Substance Produced by Enterococcus faecium EF55 on the Composition of Avian Gastrointestinal Microflora

The influence of daily orally administered crude extract of bacteriocin-like substance (at a concentration of 3200 AU/ml) produced by Enterococcus faecium EF55 on the total counts of lactobacilli, staphylococci, enterococci and E. coli in the faeces and caecum of 3-day-old Japanese quails was investigated. Enterococcus faecium EF55 was isolated from the crop content of a chicken (Gallus domesticus). The inhibitory activity of bacteriocin-like substance (BLIS) produced by the strain EF55 was assayed by the agar spot test using Gram-positive and Gramnegative indicator bacteria. A wide range of Gram-positive genera such as Enterococcus, Staphylococcus, Micrococcus, Lactobacillus, Lactococcus, Streptococcus and Aerococcus was susceptible to BLIS, but none of the Gram-negative bacteria. The antimicrobial substance produced by the strain EF55 was thermo-resistant (30 min at 100 °C), stable at pH 4.0 to 9.0 at -20 °C, 4 °C and 22 °C for 10 d tested, and inactivated by proteolytic enzymes indicating its proteinaceous nature. After the first administration of bacteriocin crude extract (BCE) of EF55 strain to Japanese quails, a reduction amounting to 0.83-1.3 log cycles of E. coli, enterococci, staphylococci and lactobacilli in faeces was observed within 24 h. This inhibitory effect was most visible after first extract addition, later this difference was diminished. By agar spot test, BLIS produced by the strain EF55 of Ent. faecium was active against Staphylococcus spp., Lactobacillus spp. and Enterococcus spp., isolates obtained from the experimental birds. However, no inhibition against E. coli was detected, despite of their decreased counts under in vivo conditions. Bacteriocin, Japanese quails, gastrointestinal microflora, effec

Lipolytic Activity of Potential Probiotic Enterococci and Additive Staphylococci

The ability to produce lipolytic enzymes by enterococci and staphylococci isolated from rabbit faeces and traditional Slovak sausages was examined. Seven strains (3 by genopypization allotted to the species Enterococcus faecium and 1 Enterococcus species of rabbit origin, 2 rabbit staphylococci and 1 Staphylococcus xylosus SX SO1/1M/1´/2 strain - sausage isolate) were lipolytic activity free, whereas lipolytic activity of remaining isolates varied in the range from 61.4 ± 0.0 to 470.7 ± 0.0 mmol/h/mg of protein. In general, enterococci isolated from sausages showed higher lipolytic activity compared to rabbit enterococci; on the other hand, rabbit staphylococci produced more lipase than was measured in staphylococci from fermented meat products. The predominance of staphylococcal lipolytic activity of both origins was detected; the selected strains could be recommended as starter culture in sausage production, e.g. by improving meat quality due to their lipid content

Distribution of aminogenic activity among potential autochthonous starter cultures for dry fermented sausages

Any bacterial strain to be used as starter culture should have suitable characteristics, including a lack of amino acid decarboxylase activity. In this study, the decarboxylase activity of 76 bacterial strains, including lactic acid bacteria and gram-positive, catalase-positive cocci, was investigated. These strains were previously isolated from European traditional fermented sausages to develop autochthonous starter cultures. Of all the strains tested, 48% of the lactic acid bacteria strains and 13% of gram-positive, catalase-positive cocci decarboxylated one or more amino acids. Aminogenic potential was strain dependent, although some species had a higher proportion of aminogenic strains than did others. Thus, all Lactobacillus curvatus strains and 70% of Lactobacillus brevis strains had the capacity to produce tyramine and beta-phenylethylamine. Some strains also produced other aromatic amines, such as tryptamine and the diamines putrescine and cadaverine. All the enterococcal strains tested were decarboxylase positive, producing high amounts of tyramine and considerable amounts of beta-phenylethylamine. None of the staphylococcal strains had tyrosine-decarboxylase activity, but some produced other amines. From the aminogenic point of view, Lactobacillus plantarum, Lactobacillus sakei, and Staphylococcus xylosus strains would be the most suitable for use as autochthonous starter cultures for traditional fermented sausages