Application of Autochthonous Biofilm-Forming Enterococcus hirae Kr8 Strain in Relation with Enterocin M in Broiler Rabbits and Their Effect on the Rabbit Meat Quality: Risk or Protection?

Around weaning, rabbits are sensitive to gastrointestinal diseases, mostly of bacterial origin, including enterococci (Enterococcus hirae), clostridia, and coliforms. Preventive use of postbiotics-enterocins-as feed additives can reduce this problem. Therefore, simulation of spoilage/pathogenic environment applying the autochthonous, biofilm-forming E. hirae Kr8+ strain in rabbits and its influence on rabbit meat quality as well as the protective effect of Ent M on rabbit meat properties and quality in infected animals was tested. Ninety-six rabbits aged 35 days, both sexes, meat line M91 breed were divided into one control (CG) and three experimental (EG1, EG2, and EG3) groups. The rabbits in CG received standard diet, without any additives, rabbits in EG1 received 108 CFU/mL of Kr8+ strain (at a dose of 500 µL/animal/day), to rabbits in EG2 the Ent M (50 µL/animal/day), and in EG3, combination of the Kr8+ and Ent M was applied in their drinking water during 21 days. The experiment lasted 42 days. The Kr8+ strain did not attack the gastrointestinal tract and have any adverse effect on the meat quality of rabbits. Moreover, improved weight gains, carcass parameters, and higher essential fatty acid (EAA) and amino acid (EAA) content of rabbit meat point rather to its possible beneficial potential in rabbit nutrition. Administration of Ent M improved most of the tested parameters: animal weight and meat physicochemical and nutritional properties, with a focus on EFA and EAA. During combination of both additives, their synergistic impact was noted, improving the nutritional quality, mostly the EAA content of rabbit meat.

Microbiota, Phagocytic Activity, Biochemical Parameters and Parasite Control in Horses with Application of Autochthonous, Bacteriocin-Producing, Probiotic Strain Enterococcus faecium EF 412.

The beneficial influence of bacteriocin-producing, probiotic, mostly non-autochthonous bacteria has already been reported in various animals. However, their use in horses provides limited information, and results with autochthonous bacteria have not been reported. Therefore, the main objective of this model study was to test the effect of autochthonous, bacteriocin-producing faecal strain Enterococcus faecium EF 412 application in horses. One gram of freeze-dried EF 412 strain (109 CFU/mL for 21 days) was applied to horses in a small feed ball. Clinically healthy horses (12), Slovak warm-blood breed of various ages (5-13 years), were involved in a 35-day-long experiment, also functioning as control for themselves. They were stabled in separate boxes (university property), fed twice a day (hay, whole oats or grazed) with water access ad libitum. Sampling was performed at the start of the experiment, i.e. at days 0/1, 21 (3 weeks of EF 412 application) and at day 35 (2 weeks of EF 412 cessation). EF 412 colonized GIT of horses was 3.54 ± 0.75 CFU/g (log 10) at day 21. The eggs of the nematode Strongylus spp. were not found in horses after EF 412 application, and Eimeria spp. oocysts were similarly not found. The other microbiota were not reduced as evaluated by the use of standard method. Using next-generation sequencing, at phylum level, phyla Bacteroidetes and Firmicutes dominated and at family level, they were Bacteroidales BS11 and S24-7 gut goups and Lentisphaerae. In horses, the increasing tendency in phagocytic activity was noted after EF 412 application. Biochemical parameters were in the physiological range. Total protein value was significantly decreased at day 21 compared with day 0/1 as well as with day 35 (P < 0.05). Cholesterol and triglycerides were influenced (decreased) at day 21 compared with day 0/1 and day 35. Neither nematode eggs Strongylus spp. nor Eimeria spp. oocysts were found in faeces after EF 412 application. Autochthonous, faecal strain E. faecium EF 412 showed promising application potential.

Enterocin M in Interaction in Broiler Rabbits with Autochthonous, Biofilm-Forming Enterococcus hirae Kr8 Strain.

Young rabbits are susceptible to gastrointestinal diseases caused by bacteria. Enterococcus hirae can be associated with diseases. But enterocins produced by some enterococcal species can prevent/reduce this problem. Therefore, the interaction of enterocin M with a biofilm-forming, autochthonous E. hirae Kr8+ strain was tested in rabbits to assess enterocin potential in vivo. Rabbits (96), aged 35 days, both sexes, meat line M91 breed were divided into four groups, control C and three experimental groups. The rabbits in C received the standard diet, rabbits in experimental group 1 (E1) received 108 CFU/mL of Kr8+, a dose 500 µL/animal/day, E2 received Ent M (50 µL/animal/day), and E3 received both Kr8+ and Ent M in their drinking water over 21 days. The experiment lasted 42 days. Feces and blood were sampled at day 0/1 (at the start of the experiment, fecal mixture of 96 animals, n = 10), at day 21 (five fecal mixtures per group, n = 5), and at day 42 (21 days after additives cessation, the same). At days 21 and 42, four rabbits from each group were slaughtered, and cecum and appendix were sampled for standard microbial analysis. Ent M showed decreased tendency of Kr8+. Using next-generation sequencing, the phyla detected with the highest abundance were Firmicutes, Verrucomicrobia, Bacteroidetes, Tenericutes, Proteobacteria, Cyanobacteria, Saccharibacteria, and Actinobacteria. Interaction of Ent M with some phyla resulted in reduced abundance percentage. At day 21, significantly increased phagocytic activity (PA) was found in E1 and E2 (p < 0.001). Kr8+ did not attack PA and did not stimulate oxidative stress. But Ent M supported PA. The prospective importance of this study lies in beneficial interaction of enterocin in host body.

Effect of enterocin M and durancin ED26E/7 supplementation on blood parameters, immune response and jejunal morphometry in rabbits.

Natural feed additives application in rabbit nutrition can help to control and prevent digestive disturbances and improve gut health and immunity around the critical weaning period. While probiotics are frequently used in rabbits, in vivo administration of bacteriocins is often limited. Therefore, the present study evaluates the effect of enterocin EntM, durancin EntED26E/7 and their combination on serum biochemistry, phagocytic activity and jejunal morphometry of rabbits. Eighty rabbits (aged 35 days, meat line M91, both sexes) were divided into experimental groups E (EntM; dose 50 µl/animal/day, activity 25,600 AU/ml), D (EntED26E/7; 50 µl/animal/day, 12,800 AU/ml), E + D (50 µl EntM + 50 µl EntED26E/7 /animal/day) and control group (C). Additives were administrated in drinking water for 21 days. Both enterocins positively influenced tested serum parameters, with emphasis on durancin EntED26E/7 administration, alone and/or in combination with EntM. Increased total proteins (E, D: p < 0.001), urea (D: p < 0.001), albumin (D: p < 0.05) and triglycerids (E, D, E+D: p < 0.001) were found. Hypocholesterolaemic effect of both additives was recorded (p < 0.001), with the lowest HDL concentration in E + D. The most of tested hepatic enzymes were positively influenced by enterocins combination (E + D; p < 0.001). The lowest AST was noted in group D (p < 0.001). Mineral profile was also improved (p < 0.001), with the highest values in D. Oxidative stress, was not evoked during enterocins application. Both additives showed a tendency to improve phagocytic activity (prolonged effect of EntED26D/7; D, E+D: p < 0.05) and jejunal morphometry parameters (increased villus cut surface; E, D, E+D; p < 0.001). Diet supplementation with EntM and mostly with EntED26E/7 can improve serum biochemistry, phagocytic activity and jejunal morphometry.

Changes in the Antioxidant and Mineral Status of Rabbits After Administration of Dietary Zinc and/or Thyme Extract.

This study was aimed at determining the impact of organic zinc (Zn) and thyme extract (TE) administration, given alone or together for 6 weeks, on the antioxidant and mineral status (Zn, Cu, Fe, and Mn) in the plasma and tissues of growing rabbits. A total of 96 rabbits of age 35 days were randomly assigned to one of four treatment groups: a control group (C), a Zn group supplemented with dietary zinc (50 mg/kg), a TE group receiving thyme extract applied in drinking water (1 ml/L), and a Zn + TE group treated with both additives. Lipid peroxidation in the plasma was influenced by Zn intake and in the kidney was affected by both the Zn and TE treatment (P < 0.05). Zn supplementation led to a significant increase in glutathione peroxidase activity (P = 0.017), total antioxidant capacity (P = 0.009) and total thiol groups level (P = 0.047) in the kidney, with the highest values occurring in rabbits receiving the combination Zn + TE. Administration of TE influenced Zn content in the kidney (P < 0.001), while zinc intake decreased Cu concentration in muscle (P = 0.021). In conclusion, the simultaneous administration of organic Zn and TE positively affected the antioxidant response of kidneys and can be used for improving the antioxidant status of growing rabbits.

Susceptibility to Enterocins and Lantibiotic Bacteriocins of Biofilm-Forming Enterococci Isolated from Slovak Fermented Meat Products Available on the Market.

This study investigated eight types of Slovak dry fermented meat products (salami and sausages) that are available on the market and were produced by three different producers in different regions of Slovakia. The total counts of enterococci in these products ranged from 2.0 up to 6.0 cfu/g (log10). Three species were identified among the 15 selected enterococcal strains; Enterococcus faecium (8 strains), Enterococcus faecalis (3) and Enterococcus hirae (4). They were hemolysis-negative (γ-hemolysis) with a biofilm-forming ability, which was evaluated as low-grade biofilm formation, susceptible to conventional antibiotics and mainly susceptible to lantibiotic bacteriocins, namely, gallidermin and nisin; they even showed a higher susceptibility to gallidermin than to nisin. They were also susceptible to enterocin-durancin, but most strains showed resistance to enterocin A/P. This study indicated that bacteriocins can play a key role in preventing and/or protecting from undesirable bacterial multiplication or contamination in the food industry and that they have great potential for further experimental applications.

Can Enterocin M in Combination with Sage Extract Have Beneficial Effect on Microbiota, Blood Biochemistry, Phagocytic Activity and Jejunal Morphometry in Broiler Rabbits?

The present study investigated the effects of enterocin (Ent) M and sage extract alone and also in combination on the gut microflora, phagocytic activity, blood biochemistry, and morphometry of rabbits. Sixty-four rabbits (aged five weeks, M91 meatline, both sexes) were divided into three experimental groups: E (EntM; 50 µL/animal/day), S (sage; 10 µL/animal/day), and E + S (EntM + sage) groups and control group (C). The additives were administered in drinking water for a period of 21 days. Dietary supplementation of EntM and sage significantly reduced the coliforms (E: p < 0.001; S: p < 0.001; E + S: p < 0.001) in feces, while simultaneous addition of EntM and sage decreased enterococci (E + S: p < 0.0001), lactic acid bacteria (E + S: p < 0.01), and coagulase-positive staphylococci (E + S: p < 0.0001) in the appendix. Sage addition reduced HDL (S: p < 0.001) and LDL cholesterol (S: p < 0.001; E + S: p < 0.001), LDL/HDL ratio (S: p < 0.001; E + S: p < 0.01), and increased urea (S: p < 0.01; E + S: p < 0.001) and creatinine (S: p < 0.001; E + S: p < 0.001) in serum. EntM and sage application, alone or in combination, improve the jejunal morphometry (p < 0.0001) in rabbits.

Benefits of Enterocin M and Sage Combination on the Physico-chemical Traits, Fatty Acid, Amino Acid, and Mineral Content of Rabbit Meat.

Higher rabbit meat consumption can be ensured by increasing of its quality due to its improved nutritional properties. The effect of enterocin M (EntM) and sage on growth performance, physico-chemical properties, fatty acid (FA), amino acid (AA), and mineral concentrations of rabbit meat was evaluated. Sixty-four rabbits (M91 meatline, both sexes) were divided into three experimental: E (EntM), S (sage), E + S (EntM + sage) groups and control group (C). The additives were administrated in drinking water during 21 days. Lower pH (E, S: P < 0.05; E + S: P < 0.001) and decrease in water content were noted in all experimental groups compared with controls (C). Higher values of lightness (L*), yellowness (b*), and redness (a*; except group E) were measured. The sage administration increased the fat and protein contents (P < 0.05), the meat energy value (S vs. C: P < 0.01; S vs. E and E + S: P < 0.05), the concentrations of arachidonic (P < 0.05), eicosapentaeonic (P < 0.05), and oleic acids (P < 0.01), magnesium (P < 0.05), and potassium (P < 0.01) content. The additives did not influence the rabbit meat AA composition. The sage diet inclusion could improve the quality of rabbit meat due to its higher protein, fat, and energy contents and enhance the PUFA and mineral content of rabbit meat. Moreover, the effect of EntM on meat color parameters, FA and AA composition, has not been tested in rabbits previously.

Some safety aspects of enterococci isolated from Slovak lactic acid dairy product "zincica".

In Slovakia, dairy products made from ewes' milk have a long tradition. These products include the lactic acid product called "zincica" which is a by-product occurring during the preparation of ewes' lump cheese. There is no information in the literature regarding the special properties of the microbiota, especially lactic acid Firmicutes, which can survive in "zincica." From the safety aspect, enterococci are a controversial group of bacteria, and those from "zincica" have never been tested for their properties. The "zincica" used in our study was supplied by several different agrofarms producing ewes' lump cheese in central Slovakia. The species Enterococcus faecium (strains EF30E1, EF32E1, EF34E1, EF34E5) and Enterococcus faecalis (strains EE30E4, EE35E1, E31E2, altogether 7) were detected in samples from "zincica" identified using MALDI-TOF spectrometry with secure genus identification/probable species identification and then confirmed by means of PCR. Enterococci were hemolysis-negative and the genes of the typical enterococcal virulence factors were mostly absent; the gelE gene was found in two E. faecium strains (EF30E1 and EF32E1), the agg gene was detected in E. faecalis EE35E1, and the esp gene was found in two E. faecalis strains (EE30E4 and EE31E2). No strains harbored the cytolysin A gene. Biofilm formation was detected in four strains (EF30E1, EF32E1, EF34E1, and EF34E5), indicating highly positive and low-grade positive biofilm formation. Enterococci were mostly susceptible to antibiotics tested for their phenotype. This is the first study to analyze enterococci in "zincica."

Enterococci Isolated from Trout in the Bukovec Water Reservoir and Cierny Váh River in Slovakia and Their Safety Aspect.

The aim of this study was to investigate enterococci as lactic acid bacteria and as part of Firmicutes phylum. We focused on the virulence factor, biofilm formation, and antibiotic resistance and also on lactic acid production and enterocin gene detection. Intestinal samples were taken from 50 healthy trout (3 Salmo trutta and 47 Salmo gairdneri) collected in April 2007, 2010, and 2015 from different locations at the Bukovec water reservoir and the Cierny Váh River in Slovakia. Twenty pure colonies were identified using the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry identification system based on protein fingerprints, and then seven identified strains were also phenotyped. Based on the identification methods used, the identified enterococci (7) belong taxonomically to four different enterococcal species: Enterococcus durans, E. faecium, E. mundtii, and E. thailandicus. They were hemolysis, DNase, and gelatinase negative with acceptable enzymatic activity. They did not form biofilm and were mostly susceptible to antibiotics. All strains produced lactic acid amounting to 1.78 ± 0.33 mmol/l on average and possessed the gene for enterocin A production. This is the first study reporting more detailed properties of enterococci from trout in Slovakian wild water sources, and it produces new possibilities for studying microbiota in trout.

Relation to enterocins of variable Aeromonas species isolated from trouts of Slovakian aquatic sources and detected by MALDI-TOF mass spectrometry.

Aeromonads represent bacteria thought to be primarily mostly autochthonous to aquatic environments. This study was focused on the relation with antibiotics and enterocins of identified Aeromonas species isolated from the intestine of trouts living in Slovakian aquatic sources. Intestinal samples from 50 trouts (3 Salmo trutta and 47 Salmo gairdnerii) were collected in April of years 2007, 2010, and 2015 from trouts of different water sources in Slovakia (pond Bukovec near Kosice, river Cierny Váh). Due to the MALDI-TOF mass spectrometry evaluation, 25 strains were proposed to the genus Aeromonas involving nine different species (Aeromonas bestiarum-nine strains, Aer. salmonicida-four strains, Aer. encheleia, Aer. eucrenophila, Aer. molluscorum, Aer. media, Aer. sobria, Aer. popoffii, Aer. veronii). Phenotypic evaluation of individual strains confirmed their species identification. Twenty-five strains of different Aeromonas species were sensitive to azithromycin, amikacin, mecillinam, mezlocillin, piperacillin, gentamicin, chloramphenicol, and tetracycline. On the other side, they were resistant to carbenicillin and ticarcillin. The growth of Aer. bestiarum R41/1 was inhibited by treatment with Ent M and Ent 2019 (inhibition activity 100 AU/mL). Aer. bestiarum R47/3 was inhibited by eight enterocins (100 AU/mL). It is the first study testing enterocins to inhibit the growth of Aeromonas species from trouts.

Enterocin M and its Beneficial Effects in Horses-a Pilot Experiment.

Probiotic bacteria or their antimicrobial proteinaceous substances called bacteriocins (enterocins) hold promising prophylactic potential for animal breeding. This study present the results achieved after application of Enterocin M in horses. Enterocin M has never been applied to horses before. Clinically healthy horses (10) were involved in this pilot experiment. They were placed in the stables of the University of Veterinary Medicine and Pharmacy, Kosice, Slovakia, with the approval of the University Ethics Committee. The animals were fed twice a day with hay and oats, or alternatively grazed with access to water ad libitum. The experiment lasted 6 weeks. Sampling was performed at the start of the experiment, at day 0-1, at day 21 (3 weeks of Enterocin M application), and at day 42 (3 weeks of cessation). Feces were sampled directly from the rectum and blood from the vena jugularis; the samples were immediately treated and/or stored for analyses. Each horse itself represented a control animal (compared to its status at the start of the experiment, day 0-1). After initial sampling, the horses were administered 100 µl of Ent M (precipitate, 12,800 AU/ml) in a small feed bolus to ensure it was consumed; Ent M was applied for 3 weeks (21 days). Fecal samples were treated using the standard microbial dilution method; phagocytic activity was assessed with standard and flow cytometry; biochemistry and metabolic profiles were tested using commercial kits and standard methods. Administration of Ent M led to mathematical reduction of coliforms, campylobacters (abP < 0.05), and significant reduction of Clostridium spp. (abP < 0.001, bcP < 0.001); increase of PA values was noted (P < 0.05, P < 0.0001); no negative influence on hydrolytic enzyme profile or biochemical blood parameters was noted.

Sensitivity to Enterocins of Biogenic Amine-Producing Faecal Enterococci from Ostriches and Pheasants.

Enterococci are widespread bacteria forming the third largest genus among lactic acid bacteria. Some possess probiotic properties or they can produce beneficial proteinaceous antimicrobial substances called enterocins. On the other hand, some enterococci produce biogenic amines (BAs), so this study is focused on the sensitivity to enterocins of biogenic amine-producing faecal enterococci from ostriches and pheasants. Altogether, 60 enterococci isolated from faeces of ostriches and pheasants were tested for production of BAs. This target of the identified enterococci involved 46 strains selected from 140 ostriches and 17 from 60 pheasants involving the species Enterococcus hirae, E. faecium, E. faecalis, and E. mundtii. Although BAs histamine, cadaverine, putrescine, and tryptamine were not detected in the enterococci tested, in general high BA production by the tested enterococci was noted. The species E. hirae formed the majority of the enterococcal strains from ostrichs faeces (34 strains). High production of tyramine (TYM) was measured with an average amount of 958.16 ± 28.18 mg/ml. Among the enterococci from pheasants, the highest was production of TYM compared to phenylethylamine, spermidine, and spermine. Enterococci featured high BA production; however, they were sensitive to seven enterocins with inhibition activity ranging from 100 up to 25,600 AU/ml.

Effect of lantibiotic gallidermin against biogenic amine-producing faecal staphylococci from ostriches and pheasants.

In ostriches and pheasants, there is still limited information relating to staphylococci and their properties. Biogenic amines (BAs) are nitrogenous low-molecular-weight substances with biological functions in animals, plants and microorganisms. In this study, we focused on BA production by targeted faecal staphylococci from ostriches and pheasants and their sensitivity to lantibiotic bacteriocin gallidermin. Gallidermin belongs in a group of polycyclic proteinaceous antimicrobial substances. Thirty-six faecal staphylococci (24 strains from 140 ostriches, 12 from 60 pheasants) comprising different species were tested. Staphylococci from ostriches and pheasants did not produce tryptamine-TRYP, putrescine-PUT, cadaverine-CAD or histamine-HIS. Production of tyramine-TYM, phenylethylamine-PEA was high or very high (100-1000 mg/L). Production of spermine-SPM and spermidine-SPD by staphylococci was very low or low although in the case of staphylococci from pheasants medium production of SPM was found. Because of the risk posed by BAs for consumers, the control of BA-producing bacteria is important from the points of view not only of safety assessment of food-producing animals but also of human health safety. The sensitivity to gallidermin in biogenic amine-producing staphylococci from ostriches and pheasants detected here is the most promising indication for further application of gallidermin for veterinary purposes. The novelty of our study lies in testing the ability of faecal staphylococci from ostriches and pheasants to produce BAs and in their treatment with gallidermin which has so far not been tested in this way.

Staphylococci Related to Farm Ostriches and Their Sensitivity to Enterocins.

In Slovakia, ostriches are reared mainly for their meat. There is still limited information related to microflora of ostriches, including staphylococci. Knowing the composition of microflora is very important for the recognition of potential pathogenic agents. Recently, a frequent problem in animals is the occurrence of bacteria resistant to antibiotics. The aim of this study was to detect staphylococcal species in feces of farm ostriches and to test their sensitivity to antibiotics and enterocins. Altogether 140 ostriches from three age groups were sampled (n = 18, faecal mixture samples from each group) on a farm in Slovakia or on Slovak farm. From 54 fecal samples, the staphylococcal count reached an average 4. 3 ± 0. 63 (log10) CFU/g. Twenty-four lactic acid producing strains were taxonomically classified to eight species of the genus Staphylococcus: Staphylococcus equorum, S. xylosus, S. epidermidis, S. haemolyticus, S. cohnii, S. succinus, S. warneri, and S. hominis. Strains were evaluated by secure probable species identification/probable species identification (score value up to 2.299) confirmed also by phenotypization. Most strains were sensitive to antibiotics. Four strains (S. haemolyticus SHae 111, S. haemolyticus SHAe 371, S. xylosus SX 2133, and S. warneri SW 292) were resistant to methicillin but sensitive to six or five of the seven enterocins tested (inhibitory activity 200-12,800 AU/mL). S. warneri SW 292 was sensitive to all enterocins (activity up to 12,800 AU/mL).

Enterococci isolated from farm ostriches and their relation to enterocins.

The present study focuses on the detection of enterococci in ostrich faeces. Forty-six bacterial colonies from 140 ostriches were identified at the species level using the MALDI-TOF MS identification system. According to the score value evaluation, they were allotted to the species Enterococcus hirae, Enterococcus faecium and Enterococcus mundtii confirmed also by phenotypic testing. Dominated species E. hirae (34 strains) were submitted to more detailed testing. Those strains E. hirae produced either no or only slight amount of the enzymes related to disorders (N-acetyl-ß-glucosaminidase, ß-glucuronidase, α-chymotrypsin, trypsin). Most of the strains were not hemolytic. They did not harbour the hiracin-producing gene. Five E. hirae strains harboured virulence factor gene gelE; however, they were phenotypically gelatinase negative. They also harboured other virulence factor genes such as esp, efaAfm and ccf. E. hirae strains were mostly sensitive to antibiotics and those resistant at least to one antibiotic were sensitive to enterocins (200-25,600 AU/mL). This study represents original and novel results concerning the enterococcal microflora in ostriches; enterococci in ostriches have not been described in detail up to now; sensitivity to enterocins of E. hirae strains harbouring virulence factor genes to enterocins is also new.

Virulence factors genes in enterococci isolated from beavers (Castor fiber).

Only limited information exists concerning the microbiota in beaver (Castor fiber). This study has been focused on the virulence factors genes detection in enterococci from beavers. In general, animals are not affected by enterococcal infections, but they can be a reservoir of, e.g. pathogenic strains. Moreover, detection of virulence factors genes in enterococci from beavers was never tested before. Free-living beavers (12), male and female (age 4-5 years) were caught in the north-east part of Poland. Sampling of lower gut and faeces was provided according to all ethical rules for animal handling. Samples were treated using a standard microbiological method. Pure bacterial colonies were identified by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) identification system. Virulence factors genes-gelE (gelatinase), agg (aggregation), cylA (cytolysin A), efaAfs (adhesin Enterococcus faecalis), efaAfm (adhesin Enterococcus faecium) and esp (surface protein) were tested by PCR. Moreover, gelatinase and antibiotic phenotypes were tested. Species detected were Enterococcus thailandicus, E. faecium, E. faecalis and Enterococcus durans. In literature, enterococcal species distribution was never reported yet up to now. Strains were mostly sensitive to antibiotics. Vancomycin-resistant E. faecalis EE9Tr1 possess cylA, efaAfs, esp and gelE genes. Strains were aggregation substance genes absent. Adhesin E. faecium (efaAfm) gene was detected in two of three E. faecium strains, but it was present also in E. thailandicus. Esp gene was present in EE9Tr1 and E. durans EDTr92. The most detected were gelE, efaAfm genes; in EF 4Hc1 also gelatinase phenotype was found. Strains with virulence factors genes will be tested for their sensitivity to antimicrobial enterocins.

Beneficial effect of lantibiotic nisin in rabbit husbandry.

Nisin is a bacteriocin marketed as Nisaplin. The aim of our work was to test its in vivo effect in a rabbit model; its effect on phagocytic activity (PA) and morphometry has not so far been studied. Post-weaning rabbits (48), 5 weeks old (both sexes, Hycole breed), were divided into the experimental (E) and the control groups (C), 24 animals in each. They were fed a commercial diet with access to water ad libitum. Rabbits in E had nisin additionally administered to their drinking water (500 IU-20 µg per animal/day) for 28 days. The experiment lasted 42 days. On day 28, significant decrease in coagulase-positive (CoPS) staphylococci and coliforms was noted (p < 0.01) in faeces of group E compared with C. Pseudomonads and clostridiae were also significantly reduced (p < 0.001; p < 0.05) and slight decrease was also in CoNS and enterococci. On day 42, coliforms were still significantly reduced (p < 0.001) in faeces; slight decrease in CoPS and pseudomonads was noted. In the caecum, significant decrease in pseudomonads (p < 0.05) was noted on day 28; slight decrease in coliforms. In the appendix slight decrease in coliforms, pseudomonads was obtained on both days. PA was increased significantly in E on days 28, 42 (p < 0.001). Biochemical parameters were not influenced; nor were volatile fatty acids or lactic acid in the chymus. Nisin application did not evoke oxidative stress. In group E, an increase in average body weight gain (about 9.4 %) was noted. The villus height/crypt depth ratio was not influenced; that is, resorption surface and functionality of mucosa were not influenced.

Clinical streptococci and their sensitivity to enterocins produced by different strains of the species Enterococcus faecium (short communication).

In children, acute otitis media (AOM) is one of the most frequently occurring infections caused by Streptococcus pneumoniae and Str. pyogenes. The standard treatment of AOMis provided by antibiotics; however, an increased resistance of the causative agents to antibiotics requires the need to search for innovations. This study was focused on in vitro testing sensitivity of streptococci isolated from AOM to enterocins produced by 9 different origin strains of E. faecium. Enterocins (Ent) represent ribosomally synthesized proteinaceous substances with antimicrobial activity against Gram-positive and/or Gram-negative bacteria which are produced mostly by strains of the species Enterococcus faecium. Str. pneumoniae were sensitive at least to 1 Ent. Str. pneumoniae SPn 754 was sensitive to 5 Ent. Five Str. pyogenes were sensitive to enterocins. Ent A (P) inhibited the growth of 3 Str. pneumoniae, and 4 Str. pyogenes (activity between 100 and 3,200 AU/ml). Most of Ent inhibited the growth of streptococci tested (100-3,200 AU/ml). Str. pyogenes were more sensitive to Ent than Str. pneumoniae. Although more detailed further studies are required, our results indicate a new possibility for enterocin use.