Enterococcus Durans Strain Research Articles

Anti-inflammatory effect of lignans from flaxseed after fermentation by lactiplantibacillus plantarum SCB0151 in vitro.

Lignan, a beneficial constituent of Flaxseed (Linum usitatissimum L.) showed great interest in researchers because of its multiple functional properties. Nonetheless, a challenge arises due to the glycosidic structure of lignans, which the gut epithelium cannot readily absorb. Therefore, we screened 18 strains of Lactiplantibacillus plantarum, Lacticaseibacillus casei, Lactobacillus acidophilus, Lacticaseibacillus rhamnosus, Pediococcus pentosaceus, Pediococcus acidilactici, and Enterococcus durans to remove glycosides from flaxseed lignan extract enzymatically. Among our findings, Lactiplantibacillus plantarum SCB0151 showed the highest activity of β-glucosidase (8.91 ± 0.04 U/mL) and higher transformed efficiency of Secoisolariciresinol (SECO) (8.21 ± 0.13%). The conversion rate of Secoisolariciresinol diglucoside (SDG) and the generation rate of SECO was 58.30 ± 3.78% and 32.13 ± 2.78%, respectively, under the optimized conditions. According to the LC-HRMSMS analysis, SECO (68.55 ± 6.57 µM), Ferulic acid (FA) (32.12 ± 2.50 µM), and Coumaric acid (CA) (79.60 ± 6.21 µM) were identified in the biotransformation products (TP) of flaxseed lignan extract. Results revealed that the TP exhibited a more pronounced anti-inflammatory effect than the flaxseed lignan extract. SECO, FA, and CA demonstrated a more inhibitory effect on NO than that of SDG. The expression of iNOS and COX-2 was significantly suppressed by TP treatment in LPS-induced Raw264.7 cells. The secretion of IL-6, IL-2, and IL-1β decreased by 87.09 ± 0.99%, 45.40 ± 0.87%, and 53.18 ± 0.83%, respectively, at 60µg/mL of TP treatment. Given these data, the bioavailability of flaxseed lignan extract and its anti-inflammatory effect were significantly enhanced by Lactiplantibacillus plantarum SCB0151, which provided a novel approach to commercializing flaxseed lignan extract for functional food.

Screening and characterization of Enterococcus durans isolates from raw organic milk in Southern Brazil: Assessing technological potential

This study assessed 34 strains of Enterococcus durans isolated from 8 samples of raw organic milk collected in both winter and summer seasons, with the aim of evaluating their technological capability. To achieve this, the following traits were tested: diacetyl production capability, autolysis capacity, organic acid production, expression of proteolytic and lipolytic enzymes, antagonistic capacity against pathogenic bacteria, as well as resistance to different types of antibiotics, hemolysin production, gelatinase production, and biofilm formation ability, as virulence factors. It was observed that 2.9% of the isolates exhibited the ability to produce diacetyl and showed proteolytic and autolytic capacity. Additionally, 8.8% displayed autolytic capacity, and 5.9% exhibited antagonistic capacity against Escherichia coli and Listeria monocytogenes, demonstrating that there are isolates with technological use potential.

A synbiotic made of an autochthonous Enterococcus durans strain and microbial polysaccharides improves broiler chicken health

PurposeThe gastrointestinal tract (GI) of organically fed desi chickens fosters a microbiota that can exclude pathogens and be potentially probiotic for improving the gut health of commercial chickens. MethodsA panel of strains were selectively cultured from desi chicken intestine and screened for their antagonism towards specific pathogens. Treating the culture free supernatant (CFS) of such strains with NaOH and proteases gives a picture of the antibacterial compound's biochemistry and determining its minimum inhibitory concentration (MIC) provides a measure of potency. The most strongly antagonistic strains were tested in vitro for surviving the chicken GIT. Safety was examined using mucin degradation, gelatin liquefaction, hemolysis, antibiotic susceptibility and biogenic amine production. An in vivo trial was done on young male Ross chickens to evaluate the performance of a bespoke synbiotic formulation comprising of an Enterococcus durans strain (1x108 CFUg−1) with prebiotics Dextran or Levan (0.1% w/v) and with both and assessing its impact on broiler gut microbiota, body and carcass weight, histopathology of organ tissues, and biochemical markers. ResultsA panel of Enterococcus spp. (NPL1315-NPL1334) was obtained and the selected strains (NLP-1319, 20, 24, 27, 34) showed good bile, acid and phenol survival, and cell surface hydrophobicity but not autoaggregation and none of them were deemed unsafe. The synbiotic-fed chickens were significantly heavier, with lowered serum cholesterol, triglycerides and glucose levels and a lesser load of pathogens than the controls. ConclusionDesi chicken intestine can be a viable source of probiotics with good antagonistic potential capable of replacing antibiotics in poultry feed.

Photoprotection Against UV-Induced Skin Damage Using Hyaluronic Acid Produced by Lactiplantibacillus plantarum and Enterococcus durans

Exposure to ultraviolet (UV) radiation is one of the major factors that causes skin aging, erythema, sunburns, and skin cancer. This study aimed to select probiotic bacterial isolates able to produce high yield of hyaluronic acid (HA) to be employed for skin photoprotection and other possible biological applications. The selected isolates K11 and St3 were able to produce the highest yields of HA 4.8 and 4.4 mg/ml, respectively. Both isolates were identified as Enterococcus durans strain K11 and Lactiplantibacillus plantarum strain St3 using 16S rRNA gene sequencing. The antioxidant activity of HA produced by E. durans strain K11 and L. plantarum strain St3 was (65.4 0.2%) and (66.6 0.1%), respectively. The viability of UVB-irradiated keratinocytes pre-treated with HA produced by E. durans strain K11 and L. plantarum strain St3 was 91.3 and 91.4%, respectively, compared with the control. While the viability of UVB-irradiated keratinocytes post-treated with HA produced by E. durans strain K11 and L. plantarum strain St3 was 86 and 88.5%, respectively. To the best of our knowledge, this is the first recordation of HA production by Enterococcus durans and Lactiplantibacillus plantarum which revealed a significant radioprotection of the human keratinocytes against UVB radiation.

The Fight against the Carcinogenic Epstein-Barr Virus: Gut Microbiota, Natural Medicines, and Beyond.

Despite recent advances in oncology, cancer has remained an enormous global health burden, accounting for about 10 million deaths in 2020. A third of the cancer cases in developing counties are caused by microbial infections such as human papillomavirus (HPV), Epstein-Barr Virus (EBV), and hepatitis B and C viruses. EBV, a member of the human gamma herpesvirus family, is a double-stranded DNA virus and the primary cause of infectious mononucleosis. Most EBV infections cause no long-term complications. However, it was reported that EBV infection is responsible for around 200,000 malignancies worldwide every year. Currently, there are no vaccines or antiviral drugs for the prophylaxis or treatment of EBV infection. Recently, the gut microbiota has been investigated for its pivotal roles in pathogen protection and regulating metabolic, endocrine, and immune functions. Several studies have investigated the efficacy of antiviral agents, gut microbial metabolites, and natural products against EBV infection. In this review, we aim to summarise and analyse the reported molecular mechanistic and clinical studies on the activities of gut microbial metabolites and natural medicines against carcinogenic viruses, with a particular emphasis on EBV. Gut microbial metabolites such as short-chain fatty acids were reported to activate the EBV lytic cycle, while bacteriocins, produced by Enterococcus durans strains, have shown antiviral properties. Furthermore, several natural products and dietary bioactive compounds, such as curcumin, epigallocatechin gallate, resveratrol, moronic acid, and andrographolide, have shown antiviral activity against EBV. In this review, we proposed several exciting future directions for research on carcinogenic viruses.

Antioxidant, DNA-protective, and SOS inhibitory activities of Enterococcus durans metabolites

Members of the genus Enterococcus are common gut symbiotic organisms that meet all the requirements for probiotics. In our study, the biological activity of individual fractions of metabolites excreted by probiotic bacteria of 3 strains of Enterococcus durans was studied using biosensor testing. Biosensor testing was performed using two biosensor strains (Escherichia coli MG1655 pRecA-lux and Escherichia coli MG1655 pKat-lux) and three inducers (hydrogen peroxide, dioxidin, ciprofloxacin). The study showed that the probiotic action of E. durans was associated with the activity of individual fractions of bacterial metabolites. Moreover, different fractions exhibited different profiles of biological activity. It has also been demonstrated that the metabolites of these strains can not only demonstrate protective activity but also induce DNA damage. These criteria should be considered in the initial screening of potential probiotic strains to avoid possible adverse effects.

Slovak Local Ewe's Milk Lump Cheese, a Source of Beneficial Enterococcus durans Strain.

Slovak ewe’s milk lump cheese is produced from unpasteurized ewe’s milk without any added culture. Because of the traditional processing and shaping by hand into a lump, this cheese was given the traditional specialty guaranteed (TSG) label. Up till now, there have existed only limited detailed studies of individual microbiota and their benefits in ewe’s milk lump cheese. Therefore, this study has been focused on the beneficial properties and safety of Enterococcus durans strains with the aim to contribute to basic dairy microbiology but also for further application potential and strategy. The total enterococcal count in cheeses reached 3.93 CFU/g (log 10) ± 1.98 on average. Based on a MALDI-TOF mass spectrometry evaluation, the strains were allotted to the species E. durans (score, 1.781–2.245). The strains were gelatinase and hemolysis-negative (γ-hemolysis) and were mostly susceptible to commercial antibiotics. Among the strains, E. durans ED26E/7 produced the highest value of lactase enzyme β-galactosidase (10 nmoL). ED26E/7 was absent of virulence factor genes such as Hyl (hyaluronidase), IS 16 element and gelatinase (GelE). To test safety, ED26E/7 did not cause mortality in Balb/c mice. Its partially purified bacteriocin substance showed the highest inhibition activity/bioactivity against Gram-positive indicator bacteria: the principal indicator Enterococcus avium EA5 (102,400 AU/mL), Staphylococcus aureus SA5 and listeriae (25,600 AU/mL). Moreover, 16 staphylococci (out of 22) were inhibited (100 AU/mL), and the growth of 36 (out of 51) enterococcal indicators was as well. After further technological tests, E. durans ED26E/7, with its bacteriocin substance, can be supposed as a promising additive to dairy products.

Characterization of potential probiotics isolated from fermented under-utilized Chrysophyllum albidum Linn kernels using microbiological, biochemical and molecular techniques

Chrysophyllum albidum is a crop of commercial value in Nigeria, however, the seeds are either used for local games or thrown away. This study aimed at exploring this under-utilized kernel as a novel source for obtaining health beneficial bacteria with desired probiotic characteristics. Isolation of potential probiotic bacteria from naturally fermented C. albidum seeds was carried out and followed by their safety evaluation, Gram staining, catalase test, acid tolerance, bile tolerance, cellular hydrophobicity and auto-aggregation assays. 16S rRNA sequencing and the detection of bile salt hydrolase (bsh) gene were the molecular methods applied for the bacteria characterization. Three potential probiotic bacteria were isolated from the fermented seeds. All isolates were non-haemolytic, Gram positive cocci, and catalase negative, grew in 1% bile, acidic pH of 3.5, and showed good auto-aggregation property. 16Sr RNA sequencing revealed isolates to be strains of Enterococcus durans, and the bsh gene was detected in all the strains. In conclusion, novel naturally fermented foods as seen in the fermented C. albidum kernels can serve as sources for the isolation of probiotic bacteria with great interest, and thus serve as starter culture to improve the organoleptic property of dairy and non-dairy foods.

Freeze-drying of Enterococcus durans: Effect on their probiotics and biopreservative properties

The present work studied the preservation of probiotic strains of Enterococcus durans by freeze-drying. The prebiotic lactulose showed to be the best protectant agent for E. durans after freeze-drying and storage at 4 and 25 °C for 92 days. Freeze-dried E. durans LM01C01 was resistant to acid treatment and able to grow in the presence of bile. Also, freeze-dried samples grew in the presence of preservative food ingredients: potassium sorbate and sodium chloride. After addition of dried cultures in a cream cheese, the number of viable bacteria was maintained for 3 months (shelf-life of the products). The spent culture supernatant of E. durans LM01C01 showed inhibitory effects on the pathogens E. coli and S. aureus. Although the addition of dried probiotic to cream cheese did not have any effect on contamination of food matrix with E. coli, a drastic decrease of viability of S. aureus was observed. These results demonstrated the suitability of E. durans strains to develop a dried symbiotic product (probiotic plus prebiotic) that could be added to food matrices or nutraceutical products, that could also tolerate gastrointestinal conditions and may act as biopreservative too.

Complete Genomic Analysis of VRE From a Cattle Feedlot: Focus on 2 Antibiotic Resistance.

Practices in intensive animal farming such as the extensive use of antimicrobials have significant impacts on the genetic make-up of bacterial communities, especially on that of human/animal commensals. In this report, whole genome sequencing of two vancomycin-resistant enterococci (VRE) isolates from a cattle feedlot in the North West Province, South Africa, was used to highlight the threats that extensive antimicrobial usage in intensive animal rearing represents for environmental microbiomes and the food chain. The genomic DNA of the studied strains was extracted using a DNA extraction kit. Whole-genome sequencing was performed through next-generation sequencing. The genomes of Enterococcus durans strain NWUTAL1 and Enterococcus gallinarum strain S52016 consisted of 3,279,618 and 2,374,946 bp, respectively with G + C contents of 40.76 and 43.13%, respectively. Antibiotic resistance genes (ARG), plasmids and virulence factors (involved in biofilm formation, colonization and copper/silver efflux system), were detected in the genomes of both strains. The presence of these genetic determinants in the studied strains is a cause for concern as they may disseminate and find their way into the food chain via horizontal gene transfer amongst bacteria of the different ecological niches. Issues of this nature cannot be undermined and are relevant as far as food safety is concerned.

Analysis of some physicochemical, rheological, sensorial properties, and probiotic viability of fermented milks containing Enterococcus faecium and Enterococcus durans strains

The aim of this research was to observe the combined usability of Enterococcus faecium and Enterococcus durans strains, which are resistant to adverse environmental conditions, together with commercial probiotic starters in the production of probiotic fermented milk. Accordingly, eight different probiotic fermented milks were produced; AF:Lactobacillus acidophilus + Enterococcus faecium, BF:Bifidobacterium animalis subsp. lactis + Enterococcus faecium, CF:Lactobacillus casei + Enterococcus faecium, RF:Lactobacillus rhamnosus + Enterococcus faecium, AD:Lactobacillus acidophilus + Enterococcus durans, BD:Bifidobacterium animalis subsp. lactis + Enterococcus durans, CD:Lactobacillus casei + Enterococcus durans, RD:Lactobacillus rhamnosus + Enterococcus durans. As a result of the data obtained in the study, it was found that fermented dairy products containing Enterococcus faecium and Enterococcus durans had no negative effects on the physicochemical, rheological properties and probiotic viability, and positively affected the sensory properties of the samples. The viscosity and hardness values of probiotic fermented milk produced by combining with E. durans were higher than by combining with E. faecium and serum separation was not occurred. Also, probiotic bacteria viability was higher than 7 log cfu/ml level at the end of the storage period. Practical applications Enterococci are found naturally in the human intestinal microbiota and are highly resistant to adverse environmental conditions. Enterococcus strains that produce antimicrobial peptides such as enterocin were found to be able to effectively inhibit the development of many food pathogens when they are added to some foods including cheese. They are microbial additives that are thought to be used in many foods to improve food safety. The bacteriocin called enterocin could act as natural bio-preservatives in foods. This study will guide the use of Enterococcus species as bio-preservative in foods such as dairy products and the possibility of the continuation of probiotic viability.

Growth intensity and antibacterial properties of Enterococcus faecium and Enterococcus durans strains isolated from traditional Carpathian brynza

The article presents the results of the study the ability of four not studied strains of enterococci (E. durans, SB6, E. faecium SB12, E. durans SB18, E. durans SB20), which were isolated from the Carpathian brynza, to reduce the acidity of medium of cultivation, the rate of biomass accumulation and the ability to exhibit antagonistic properties to the opportunistic microflora. Lactic acid and minor compounds are producing in a result of lactose fermentation, which form the specific taste and aroma properties of the product. The activity of acid formation has crucial because it directly connected with the coagulation of proteins and the prevention of the growing of extraneous microflora. Therefore, the rate of acidity increasing of the medium is one of the most important characteristics in selection of strains of lactic acid bacteria for the manufacture of dairy products. High growth rate, resistance to the contamination of extraneous microflora and preservation of their properties in the finished product are the technological properties of the strains. The inhibition of the growth of pathogenic cultures of microorganisms is the main probiotic functions of beneficial bacteria namely antagonistic activity. It was found, that the strain E. durans SB20 manifested the highest ability to increase the acidity of the medium under the cultivation for 24 hours at 37 °C as it reduced the pH on 30.3 %, and the strain E. durans SB18 increased the acidity on 29.9 %. Under 48 hours strains E. durans SB20 and SB18 increased the acidity on 31.1 and 30.5 % (P< 0.001) respectively compared with the control. The growth rate of stains E. durans SB20 and E. durans SB18 were in 18,0 and 17,6 times higher than in control under the cultivation for 24 hours at 37 °C, the optical density were in 18.3 and 18.2 times higher respectively than in the control sample under the cultivation for 48 hours at the same temperature. Furthermore, strains of enterococci showed antagonistic properties against conditionally pathogenic cultures of microorganisms on 24 and 48 hour of cultivation. In addition, it was found that with an increasing temperature of the antagonistic activity of the strains cultivation increased. Obviously, it was connected that more biologically active substances and microbial secondary metabolites are formed under the longer cultivation and higher temperatures. In particular on 48 hours at 37 °C almost of all the tested strains showed moderate antagonistic activity against E. coli, S. enteritidis, E. aerogenes, P. mirabilis and P. aeruginosa. However, all four strains didn`t have antagonistic activity against the test-strain S. aureus.

Enterococcus durans with mosquito larvicidal toxicity against Culex quinquefasciatus, elucidated using a Proteomic and Metabolomic approach

Various bacteria from the Bacillus species have been used as pesticides against mosquito larvae for more than a decade. The prolonged use of these bacterial species by little alteration within their genome, using various permutations and combinations of mosquito-cidal toxins, has proven unsuccessful in controlling the mosquito population. In our current study we report Enterococcus sp. to be exhibiting similar kind of mosquito-cidal toxins alike those which are present in the mainly used Bacillus strains. Three Enterococcus species were isolated on a rich media selective for gram- positive bacteria from the mid-gut of dead mosquito larvae which were collected from the wild locations within and around the city of Mumbai, India. Their surface morphologies were studied by Scanning Electron Microscopy (SEM) and their identity was confirmed using the standard 16S rRNA sequencing method. Upon performing several repetitive toxicity assays of these three strains on the laboratory cultured third instar stage of Culex quinquefasciatus larvae, showed differential toxicities from a minimum of 20% (LC50: 59.6 CFU/ml), intermediate 35% (LC50: 48.4 CFU/ml) and a maximum of 60% (LC50: 35.7 CFU/ml). To justify the data in all the three similar strains of Enterococcus durans, we followed the differential proteomics using LCMS 6540 UHD Accurate Mass QTOF and differential metabolomics approach using both LCMS 6540 UHD Accurate Mass QTOF and 1H-NMR. The presence and significance of the obtained toxins were studied to elucidate the plausible reason for showing differential toxicities. This work helped in identifying Enterococcus durans as a new, potential and alternative strain to the Bacillus species in terms of mosquito larvicidal toxicity against Culex quinquefasciatus.

In vitro characterisation of probiotic properties of Enterococcus faecium and Enterococcus durans strains isolated from raw milk and traditional dairy products

In this study, some probiotic characteristics such as antimicrobial activity, vancomycin resistance, growth ability at pH, resistance to bile salts, bile salt deconjugation and hydrophobicity of 30 Enterococcus faecium and Enterococcus durans strains isolated and identified from raw milk and various dairy products were investigated. According to the study results, antimicrobial activity profiling, pH and bile salt resistance and bile salt deconjugation ability of Enterococcus strains varied depending on the species and strains and all the strains showed resistance to the tested bile salt concentrations. It was concluded that the E. faecium and E. durans strains tested showed probiotic characteristics and have the potential to be used in food production.

Potential use of probiotic Enterococcus faecium and Enterococcus durans strains in Izmir Tulum cheese as adjunct culture.

In this research, Enterococcus species with probiotic properties were isolated from raw milk and some traditional dairy products and these species were identified by using biochemical, phenotypical and genotypic methods and their potential use in Izmir Tulum cheese production as adjunct culture were investigated. Among the isolated and identified Enterococcus species, three Enterococcus faecium and one Enterococcus durans strains with no vancomycin resistance, no decarboxylation activity, high antimicrobial activity and resistance to acidity were selected, and a mix culture was produced. This culture was mixed with commercial cheese culture containing Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris in different proportions and used in Izmir Tulum cheese production. Cheese samples were left to ripening for 180days, and their physical, chemical, microbiological and sensory properties were evaluated with comparison to prior studies. Evaluations showed that using adjunct culture in Izmir Tulum cheese production has no negative effect on physical, chemical and microbiological properties and higher proportions of probiotic Enterococci in the culture have a positive effect on the sensory properties, especially on flavor.

Inhibition of herpes simplex virus 1 (HSV-1) and poliovirus (PV-1) by bacteriocins from lactococcus lactis subsp. lactis and enterococcus durans strains isolated from goat milk

Bacteriocins have unusual inhibitory activity, including antiviral properties, and this can be exploited to give alternative applications. Semi–purified bacteriocins of six lactic acid bacteria (LAB) strains isolated from goat milk (two Lactococcus lactis: GLc03 and GLc05, and four Enterococcus durans: GEn09, GEn12, GEn14 and GEn17) were tested for cytotoxicity in Vero cells (50% Cytotoxicity Concentration: CC50), and for their antiviral activities against herpes simplex virus 1 (HVS-1) and poliovirus (PV-1). Semi-purified bacteriocins presented low cytotoxicity, with CC50 varying from 256.2 µg/mL (GLc05) to 1084.5 µg/mL (GEn14). CC10 was determined for all isolates (GLc03: 36.9 µg/mL; GLc05: 51.2 µg/mL; GEn09: 88.1 µg/mL; GEn12: 99.9 µg/mL; GEn14: 275 µg/mL; and GEn17: 62.2 µg/mL) and considered for antiviral activity assays. Antiviral activity before virus adsorption was recorded against PV-1 for GLc05 (4.9%), GEn09 (3.4%), GEn12 (24.7%) and GEn17 (23.5%), and against HSV-1 for GEn12 (27.9%), GEn14 (58.7%) and GEn17 (39.2%). Antiviral activity after virus adsorption was identified against PV-1 for GLc05 (32.7%), GEn09 (91.0%), GEn12 (93.7%) and GEn17 (57.2%), and against HSV-1 for GEn17 (71.6%). The results obtained indicate the potential of some bacteriocins, particularly those produced by E. durans strains investigated in the present study, in viral inhibition and their application as new antiviral agents.

Enterococcus durans EP1 a Promising Anti-inflammatory Probiotic Able to Stimulate sIgA and to Increase Faecalibacterium prausnitzii Abundance.

Enterococcus species, principally Enterococcus faecium are used as probiotics since a long time with preference in animal applications but safety considerations were updated and also new uses as probiotics can be envisaged. Fifteen Enterococcus strains isolated from different foods were identified and analyzed for virulence factors and antibiotic resistance. Three Enterococcus durans strains were selected to study their immunomodulatory properties on PBMC and Caco2 cells. Two strains presented a profile toward a mild inflammatory Th1 response considering TNF-α/IL-10 and IL-1β/IL-10 cytokines ratios. The third strain EP1, presented an anti-inflammatory potential and was selected for in vivo studies. In mice, the strain was well tolerated and did not cause any adverse effects. EP1 administration increased the amount of IgA+ cells in mesenteric lymph node (MLN) after 7 days of administration. In fecal samples, the IgA content increased gradually and significantly from day 7 to day 21 in treated group. Additionally, IL-17, IL-6, IL-1β, IFN-γ, and CXCL1 gene expression significantly decreased on day 21 in Peyer’s patches and IL-17 decreased in MLN. Mice treated with the probiotic showed significant lower mRNA levels of pro-inflammatory cytokines and mucins in the ileum at day 7 while their expression was normalized at day 21. Colonic expression of il-1β, il6, and mucins remain diminished at day 21. Ileum and colon explants from treated mice stimulated in vitro with LPS showed a significant reduction in IL-6 and an increase in IL-10 secretion suggesting an in vivo protective effect of the probiotic treatment against a proinflammatory stimulus. Interestingly, analysis of feces microbiota demonstrated that EP1 administration increase the amount of Faecalibacterium prausnitzii, a butyrate-producing bacteria, which is known for its anti-inflammatory effects. In conclusion, we demonstrated that EP1 strain is a strong sIgA inducer and possess mucosal anti-inflammatory properties. This strain also modulates gut microbiota increasing Faecalibacterium prausnitzii, a functionally important bacterium. Thus, E. durans EP1 is not only a good candidate to increases F. prausnitzii in some cases of dysbiosis but can also be interesting in gut inflammatory disorders therapy.

Phenotypic and Genotypic Alterations of Durancin GL-Resistant Enterococcus durans Strains.

The emergence and spread of bacteriocin-resistant bacteria threaten the efficiency of bacteriocin usage as food preservatives. In this experiment, 19 selected Enterococcus durans strains acquired resistance after exposure to durancin GL, and the mutants had similar intermediate levels of resistance. One wild-type E. durans KLDS 6.0603 and its two resistant mutants, E. durans KLDS 6.0603-2 and E. durans KLDS 6.0603-3, were used to characterize phenotypic and genotypic differences. Approximately 100 μg/mL of durancin GL can penetrate the cytoplasmic membrane of E. durans KLDS 6.0603, causing damage to bacterial cells, but cannot penetrate E. durans KLDS 6.0603-2 and KLDS 6.0603-3 membranes. Unsaturated fatty acid content in resistant strains was significantly increased compared with wild-type strains, indicating that the former has more fluidity of cell membrane than the latter. Decreased mannose phosphotransferase system gene expression (mptD) was observed in the two resistant strains. Results showed that the factors, including the increased unsaturated fatty acid and decreased mptD expression, could contribute to durancin GL resistance.

Evolution of proteolysis in Urfa cheese made from ewe's milk by wild type starter culture systems

The evolution of proteolysis in Urfa cheese made from ewe's milk by using various combinations of wild-type strains of Lactococcus lactis (strain 1B4), Lactococcus garvieae (strain IMAU 50157), Enterococcus faecalis (strain KLDSO.0341), Enterococcus faecium (strain ATCC 19434) and Enterococcus durans (strain IMAU 60200) was monitored for 180 days. The strains used in the study were isolated from traditional raw ewe's milk Urfa cheese and characterized by phenotypic and genotypic studies previously. Three different combinations of the strains were employed in the manufacture of cheeses from pasteurized milk. These are: cheese A (strains 1B4+ATCC 19434+IMAU 50157), cheese B (strains 1B4+IMAU 60200+ATCC 1934) and cheese C (strains ATCC 19434+1B4+IMAU 50157+IMAU 60200+KLDSO.0341). The control cheese (cheese D) was produced from raw ewe's milk without starter culture. Proteolysis in the cheeses was evaluated using urea-PAGE of pH 4.6-insoluble and RP-HPLC of both 70% ethanol-insoluble (EtOH-i) and ethanol-soluble (EtOH-s) nitrogen fractions. The variations in water soluble nitrogen (WSN) and trichloroacetic acid-soluble nitrogen (TCA-SN) were also monitored during ripening as well as gross compositions of the cheeses. Results indicated that the degradation of casein fractions were faster in the cheeses A, B and C than the control. The peptide profiles of 70% EtOH-i and EtOH-s nitrogen of the cheeses A, B and C were close to each other but far more extensive than the control cheese. The proteolytic capacities of the strains employed in the cheeses A, B and C were superior to that of raw milk flora. To conclude, any of the combinations of the wild-type strains could be used in the production of Urfa cheese from pasteurized ewe's milk, as long as the safe use of enterococcal strains is assured.

Phenotypic expression, molecular characterization and transferability of erythromycin resistance genes in Enterococcus spp. isolated from naturally fermented food

To evaluate phenotypic resistance to macrolides-lincosamides and streptogramin B (MLSB ) antibiotics and to determine their localization as well as transferability of erythromycin resistance genes in enterococcal isolates of naturally fermented food-Idli batter. Diverse MLSB phenotypes observed among the enterococcal spp. (n=32) were analysed through double disc and triple disc test. Standard minimum inhibitory concentration tests along with induction studies displayed synergistic or cross-resistance among MLSB antibiotics. Plasmid profiling and Southern hybridization revealed that erm(B) and msr(C) genes were localized either onchromosome or on high molecular weight plasmids and showed co-localization of these genes with lnu(B), tet(L) and tet(W) in one of the isolate. In vitro conjugation experiments demonstrated plasmid-mediated transfer of erm(B) gene from three Enterococcus durans strains to Enterococcus faecalis JH2-2. The study illustrated diverse MLSB phenotypes, multiple resistance genes and transferable plasmids among enterococci isolated from naturally fermented foods. From a public health point of view, the study identified that naturally fermented foods could represent a source of antibiotic resistance enterococci that can spread through foods. These results also suggest that vigilance may be exercised with the use of combination or novel MLSB antibiotics in treating enterococcal infections.