Enterococcus Hirae Research Articles

The prevalence, antibiotic resistance and biofilm formation ability of Enterococcus spp. isolated from food products in Algeria

Enterococci are ubiquitous bacteria in the normal intestinal microbiota of both humans and animals. They can be used in the food industry as starter or probiotic cultures. However, some species have emerged as an important nosocomial pathogens, and have been implicated in severe multi-resistant infections. In this study, a total of 235 food products were analyzed for the presence of Enterococcus spp. Overall, 54 (22.9%) out of the 235 samples were contaminated and 54 strains were isolated. The latter were identified by matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and tested for antibiotic susceptibility against seven antibiotic molecules, in addition to their ability to form a biofilm. The predominant species was Enterococcus faecalis (70.4%), followed by Enterococcus hirae (12.9%), Enterococcus faecium (11.1%) and Enterococcus durans (5.5%). The highest resistance profile was ascribed to tetracycline (66.7%) and penicillin G (33.3%). Six enterococcal isolates (11.1%) were resistant to at least three antibiotic families. All isolated strains were able to form a biofilm and exhibited gelatinase activity. However, only 4 (7.4%) were β-hemolytic. This study revealed that food products might play a role in the spread of enterococci through the food chain to humans with these virulence and resistance characteristics. As a result, continuous investigations are necessary to assess the health hazards associated with the consumption of contaminated food products.

Comparison of automatic methods MALDI-TOF, VITEK2 and manual methods for the identification of intestinal microbial communities on the example of samples from alpacas (Vicugna pacos).

Universally, in microbiological diagnostics the detection of live bacteria is essential. Rapid identification of pathogens enables appropriate remedial measures to be taken. The identification of many bacteria simultaneously facilitates the determination of the characteristics of the accompanying microbiota and/or the microbiological complexity of a given environment. The effectiveness of the VITEK2 Compact automated microbial identification system and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS), analytical profile index (API) and Remel RapID tests were compared in identification of bacteria isolated from the alpaca gastrointestinal tract. Most isolates were Gram-positive, such as Bacillus cereus, Bacillus flexus, Bacillus licheniformis, Bacillus pumilus and Bacillus subtilis; Enterococcus faecium, Enterococcus gallinarum, Enterococcus hirae and Enterococcus casseliflavus; Staphylococcus aureus, Staphylococcus equorum, Staphylococcus lentus, Staphylococcus pseudintermedius and Staphylococcus sciuri; Paenibacillus amylolyticus; Cellulosimicrobium cellulans; Leuconostoc mesenteroides; Clostridium perfringens; Corynebacterium stationis, Corynebacterium xerosis, and Corynebacterium diphtheriae (the last only isolated manually by API Coryne and the VITEK2 system and Corynebacteria (CBC) card). Corynebacterium diphtheriae was misidentified by MALDI-TOF MS as Candida lipolytica (currently Yarrowia lipolytica). Gram-positive and Gram-variable Micrococcus luteus were also isolated. Gram-negative Enterobacter cloacae, Enterobacter gergoviae, Enterobacter hormaechei and Enterobacter ludwigii; E. coli; Klebsiella pneumoniae subsp. pneumoniae; Citrobacter braakii and Citrobacter freundii; Serratia liquefaciens, Serratia odorifera and Serratia marcescens; Morganella morganii subsp. morganii; Providencia alcalifaciens; Pseudomonas aeruginosa; Stenotrophomonas maltophilia; Moraxella osloensis; and Ochrobactrum intermedium were also found. The yeasts Candida albicans, Candida haemulonii and Candida ciferrii were also present. MALDI-TOF MS enabled the identification of pathogens and opportunistic pathogens from the alpaca gut which may represent a high risk to human and animal health.

In vitro Survival of Microencapsulated Canine-Specific Probiotics Under Simulated Gastrointestinal Tract Conditions and During Storage

The survival of probiotics in the gastrointestinal system of dogs is crucial for them to provide health benefits. However, probiotics must also endure various physical conditions during commercial production and storage. Therefore, this study employed the microencapsulation technique to ensure the survival of probiotics using alginate as the encapsulation material, both alone and in combination with goat milk (alginate-goat milk). The study assessed the survival rates of two probiotic LAB strains, Enterococcus hirae Pom 4 and Ligilactobacillus animalis FB2, in both types of matrices under simulated dog gastrointestinal conditions, during food production, and 28 days of refrigeration at 4°C. The findings revealed that alginate-goat milk microcapsules had the highest encapsulation yield, and the viability of microencapsulated LAB cells in the alginate-goat milk matrix was the best protection for both probiotic strains under all conditions, including pasteurization temperature. Even after pasteurization, viable counts exceeding 6 log cfu/g were observed, indicating the promising application of alginate-goat milk microcapsules for optimal protection, enabling probiotics to survive until they reach the intended site and provide health benefits to dogs.

Ultrasound-Based Recovery of Anti-Inflammatory and Antimicrobial Extracts of the Acidophilic Microalga Coccomyxa onubensis.

In the present study, the recovery of valuable molecules of proven anti-inflammatory and antimicrobial activity of the acidophilic microalga Coccomyxa onubensis (C. onubensis) were evaluated using green technologies based on ultrasound-assisted extraction (UAE). Using a factorial design (3 × 2) based on response surface methodology and Pareto charts, two types of ultrasonic equipment (bath and probe) were evaluated to recover valuable compounds, including the major terpenoid of C. onubensis, lutein, and the antimicrobial activity of the microalgal extracts obtained under optimal ultrasound conditions (desirability function) was evaluated versus conventional extraction. Significant differences in lutein recovery were observed between ultrasonic bath and ultrasonic probe and conventional extraction. Furthermore, the antimicrobial activity displayed by C. onubensis UAE-based extracts was greater than that obtained in solvent-based extracts, highlighting the effects of the extracts against pathogens such as Enterococcus hirae and Bacillus subtilis, followed by Staphylococcus aureus and Escherichia coli. In addition, gas chromatography-mass spectrometry was performed to detect valuable anti-inflammatory and antimicrobial biomolecules present in the optimal C. onubensis extracts, which revealed that phytol, sterol-like, terpenoid, and even fatty acid structures could also be responsible for the antibacterial activities of the extracts. Moreover, UAE displayed a positive effect on the recovery of valuable molecules, improving biocidal effects. Our study results facilitate the use of green technology as a good tool in algal bioprocess engineering, improving energy consumption and minimizing environmental impacts and process costs, as well as provide a valuable product for applications in the field of biotechnology.

In-vitro antimicrobial activity of essential oils of Tasmania

ABSTRACT Thirteen commercial Tasmanian essential oils were evaluated for their antimicrobial activity against 14 human pathogens and cosmetic contaminants including Enterococcus hirae, Kocuria rhizophila, Staphylococcus epidermidis, Propionibacterium acnes, Staphylococcus aureus, Escherichia coli, Klebsiella aerogenes, Klebsiella pneumoniae, Pluralibacter gergoviae, Pseudomonas fluorescens, Burkholderia cepacia, Pseudomonas putida, Aspergillus brasiliensis, and Aspergillus fumigatus. The antimicrobial activities of various essential oils were evaluated using the AlamarBlue Cell Viability Assay, covering a testing concentration range from 3.125 to 800 µg/mL. Essential oils were deemed active if their minimum inhibitory concentration (MIC) value was less than or equal to 800 µg/mL. The essential oils of Rosemary (Rosmarinus officinalis ct. α-pinene), Parsley Herb (Petroselinum crispum), and Bitter Fennels (Foeniculum vulgare) demonstrated significant growth inhibitory effects on one microorganism (P. fluorescens) within an MIC value of ≤ 800 µg/mL. Big Badja Gum (Eucalyptus badjensis), Blue Gum (Eucalyptus globulus), Peppermint (Mentha piperita), and Lavender (Lavandula angustifolia) essential oils inhibited the growth of two different microorganisms. Southern Rosalina (Melaleuca ericifolia), Parsley Seed (Petroselinum crispum), Smoky Tea Tree (Leptospermum glaucescens), and Kunzea (Kunzea ambigua) essential oils exhibited an MIC value of less than or equal to 800 µg/mL against 4, 5, 6, and 8 microorganisms respectively. Notably, Coastal Tea Tree (Leptospermum laevigatum) essential oil displayed the most profound antimicrobial activity, inhibiting 11 out of 15 microbial strains within an MIC range of 50–800 µg/mL. The results of the gas chromatography analysis showed that the coastal tea tree essential oil was composed primarily of monoterpenes, with smaller amounts of sesquiterpenes and their oxygenated derivatives. 35 Compounds were identified, representing 95.50% of the compounds in the coastal tea tree essential oil. The main constituents of this essential oil were α-pinene (34.83%), followed by α- and β-eudesmols (10.21% total), and limonene (9.56%).

Fabrication of Ag nanoparticles coated leonardite basalt ceramic membrane with improved antimicrobial properties for DNA cleavage, E. coli removal and antibiofilm effects

This study aimed to fabricate a novel, low-cost, and environmental-friendly ceramic membrane based on basalt and leonardite powders via press and sintering methods. The fabricated leonardite basalt ceramic membrane (LBCM) was coated with silver nanoparticles (AgNPs); to create an antibacterial surface. The capabilities of the bare and coated membranes were examined. In this context, water permeability reached 554 ± 2.61 and 447 ± 1.21 L/m2hbar for bare LBCM and AgNPs-coated LBCM, respectively. The fabricated membranes indicated 100% Escherichia coli (E. coli) removal efficiency at a transmembrane pressure of 0.5 bar. The solid surface antimicrobial activity of the LBCM and AgNPs-coated LBCM reached 26.38% and 100%, respectively. The LBCM and AgNPs-coated LBCM were analyzed for the in-vitro 2,2- diphenyl-1-picrylhydrazyl (DPPH) antioxidant. Accordingly, AgNPs-coated LBCM exhibited higher antioxidant activities than raw LBCM. The scavenging capacity reached 83.91% with AgNPs-coated LBCM, while only 58.95% was achieved with raw LBCM, indicating that AgNPs-coated LBCM was better than bare LBCM from an antioxidant activities perspective. AgNPs-coated LBCM had a deoxyribonucleic acid (DNA) cleavage activity (single-strand DNA cleavage activity at 50 mg/L and double-strand DNA cleavage activity at 100 and 200 mg/L). In contrast, the raw LBCM did not exhibit DNA cleavage activity at any concentration. AgNPs-coated LBCM showed higher antimicrobial activities (minimum inhibition concentrations (MICs) were 32 mg/L against Enterococcus faecalis (E. faecalis) and 64 mg/L against Staphylococcus aureus (S. aureus), Candida tropicalis (C. tropicalis), and Enterococcus hirae (E. hirae)). The biofilm inhibition of LBCM and AgNPs-coated LBCM powders was tested against S. aureus and Pseudomonas aeruginosa (P. aeruginosa). The maximum S. aureus inhabitations by LBCM and AgNP-coated LBCM were 60.34% and 99.12%, respectively. The inhabitation of P. aeruginosa increased from 52.38% before coating to 96.37% at the end of the coating process. Regarding E.coli microbial cell viability inhibition, LBCM powders and AgNPs-coated LBCM powders were found to inhibit E. coli growth by 68.35% and 100%, respectively.

Isolation and characterization of bioprotective lactic acid bacteria from Moroccan fish and seafood.

The microbiota of aquatic animals is heavily influenced by their environment, offering a potential source for biotechnologically relevant microorganisms. In this investigation, bacterial strains from fish and fish products were investigated to determine their antimicrobial effects against fish and food pathogens. Twelve strains, including five Lactococcus, two Enterococcus hirae, two Enterococcus mundtii, and three Latilactobacillus sakei were selected as producing bacteriocin-like substances with antimicrobial properties that were active against a broad spectrum of bacteria, such as Listeria monocytogenes, Staphylococcus aureus, and Pseudomonas aeruginosa. Selected strains were identified via 16S rRNA sequencing. Most strains exhibited sensitivity to eight types of antibiotics (erythromycin, tetracycline, chloramphenicol, vancomycin, fosfomycin, gentamicin, ampicillin, and netilmicin), lacked hemolysin and gelatinase virulence factors, and did not produce histamine. These findings suggest that marine fish may be a promising source of lactic acid bacteria strains with antimicrobial potential for use as biopreservatives in the food industry.

Six states of Enterococcus hirae V-type ATPase reveals non-uniform rotor rotation during turnover

The vacuolar-type ATPase from Enterococcus hirae (EhV-ATPase) is a thus-far unique adaptation of V-ATPases, as it performs Na+ transport and demonstrates an off-axis rotor assembly. Recent single molecule studies of the isolated V1 domain have indicated that there are subpauses within the three major states of the pseudo three-fold symmetric rotary enzyme. However, there was no structural evidence for these. Herein we activate the EhV-ATPase complex with ATP and identified multiple structures consisting of a total of six states of this complex by using cryo-electron microscopy. The orientations of the rotor complex during turnover, especially in the intermediates, are not as perfectly uniform as expected. The densities in the nucleotide binding pockets in the V1 domain indicate the different catalytic conditions for the six conformations. The off-axis rotor and its’ interactions with the stator a-subunit during rotation suggests that this non-uniform rotor rotation is performed through the entire complex.

Chagas disease is related to structural changes of the gut microbiota in adults with chronic infection (TRIPOBIOME Study).

The implications of the gut microbial communities in the immune response against parasites and gut motility could explain the differences in clinical manifestations and treatment responses found in patients with chronic Chagas disease. In this pilot prospective cross-sectional study, we included 80 participants: 29 with indeterminate CD (ICD), 16 with cardiac CD (CCD), 15 with digestive CD (DCD), and 20 controls without CD. Stool was collected at the baseline visit and faecal microbial community structure DNA was analyzed by whole genome sequencing. We also performed a comprehensive dietary analysis. Ninety per cent (72/80) of subjects were of Bolivian origin with a median age of 47 years (IQR 39-54) and 48.3% (29/60) had received benznidazole treatment. There were no substantial differences in dietary habits between patients with CD and controls. We identified that the presence or absence of CD explained 5% of the observed microbiota variability. Subjects with CD exhibited consistent enrichment of Parabacteroides spp, while for Enterococcus hirae, Lactobacillus buchneri and Megamonas spp, the effect was less clear once excluded the outliers values. Sex, type of visceral involvement and previous treatment with benznidazole did not appear to have a confounding effect on gut microbiota structure. We also found that patients with DCD showed consistent Prevotella spp enrichment. We found a detectable effect of Chagas disease on overall microbiota structure with several potential disease biomarkers, which warrants further research in this field. The analysis of bacterial diversity could prove to be a viable target to improve the prognosis of this prevalent and neglected disease.

Evaluation of different characteristics and bioactivities of chitosan-based films incorporating Eugenia caryophyllus and Cinnamomum zeylanicum essential oils

Nowadays, using biodegradable and active packaging as an alternative to oil-based plastics become a trend. Thus, we aimed in this study to develop and generally evaluate chitosan-based films (CH-film) incorporating C. zeylanicum and E. caryophyllus essential oils (EOs) for eventual utilization as food active-packaging. Experimental data revealed that the film thickness and opacity increased from 2.2- to 6-folds, and from 2.6- to 4.5-folds respectively, following the addition of EOs. Moreover, the treated materials revealed a significant drop in hydrophobicity, elongation at break, moisture content, and swelling degree, especially in the case of cinnamon EO treatment. A correlation was observed between the antioxidant property and total phenolic content. The DPPH inhibitory behavior and release of phenolic compounds of the treated CH-films increased over time, reaching third-day values higher than 15 mg gallic acid/g sample, and 80% of DPPH inhibition, respectively. Finally, the introduction of clove and cinnamon EOs significantly promotes the antibacterial and antibiofilm properties of the material against Escherichia coli, Enterococcus hirae, Staphylococcus aureus, and Pseudomonas aeruginosa. Biofilm inhibition values ranged from 69.76 to 96.97% depending on the bacterial species.These promising findings encourage the potential utilization of CH-films supplemented with EOs such as cinnamon and clove EOs to replace plastic-based films as packaging, especially in the agri-food industry.

Tolerance of clinical vancomycin-resistant Enterococcus faecium isolates against UV-C light from a mobile source

BackgroundAdmission to a room previously occupied by patients carrying environmentally robust pathogens implies an increased risk of acquiring those pathogens. Therefore, ‘No-touch’ automated room disinfection systems, including devices based on UV-C irradiation, are discussed to improve terminal cleaning. It is still unclear if clinical isolates of relevant pathogens behave differently under UV-C irradiation compared to laboratory strains used in the approval process of disinfection procedures. In this study we analysed the susceptibility of well characterized clonally divergent vancomycin-resistant enterococci (VRE) strains, including a linezolid-resistant isolate, against UV-C radiation.MethodsSusceptibility against UV-C of ten clonally divergent clinical isolates of VRE was determined in comparison to the commonly used test organism Enterococcus hirae ATCC 10541. Ceramic tiles contaminated with 105 to 106 colony forming units/25 cm² of the different enterococci were positioned at a distance of 1.0 and 1.5 m and irradiated for 20 s, resulting in a UV-C dose of 50 and 22 mJ/cm², respectively. Reduction factors were calculated after quantitative culture of the bacteria recovered from treated and untreated surfaces.ResultsSusceptibility to UV-C varied considerably among the strains studied, with the mean value of the most robust strain being up to a power of ten lower compared to the most sensitive strain at both UV-C doses. The two most tolerant strains belonged to MLST sequence types ST80 and ST1283. The susceptibility of the laboratory strain E. hirae ATCC 10541 ranged between the most sensitive and most tolerant isolates for both irradiation doses. However, for UV-C dose of 22 mJ/cm², the reduction of the most tolerant isolate of ST1283 was statistically significantly lower compared to E. hirae ATCC 10541. The most susceptible strains belonged to the MLST sequence types ST117 and ST203.ConclusionsThese results indicate that UV-C doses reported in the literature are sufficient for the reduction of commonly used reference strains of enterococci but could be insufficient for the reduction of tolerant patient VRE-isolates in a hospital setting. Therefore, for future studies, the most tolerant clinical isolates should be used to validate automated UV-C devices or longer exposure times should be expected to ensure efficacy in the real world.

Isolation, Characterization, and Comparative Genomics of the Novel Potential Probiotics from Canine Feces.

Lactic acid bacteria (LAB) are commonly used as probiotics; however, not all LAB strains have the same beneficial effects. To successfully use LAB as probiotics in canines, LAB species should originate from the canine intestinal tract as they display host specificity. The objective of this study was to investigate the phenotypic and genomic traits of potential probiotic LAB isolated from canine fecal samples. Twenty LAB samples were evaluated for their potential probiotic characteristics including resistance to low pH, bile salts, hydrophobicity, auto-aggregation, co-aggregation, adhesion to epithelia or mucosa, and production of inhibitory compounds. Additionally, we evaluated their safety and other beneficial effects on canine health, such as DPPH free radical scavenging, and β-galactosidase. Four strains demonstrated potential probiotic characteristics and were selected: Enterococcus hirae Pom4, Limosilactobacillus fermentum Pom5, Pediococcus pentosaceus Chi8, and Ligilactobacillus animalis FB2. Safety evaluations showed that all strains lacked hemolytic activity, could not produce biogenic amines, and did not carry any pathogenic genes. In addition, L. fermentum Pom5 and P. pentosaceus Chi8 displayed susceptibility to all antibiotics and concordant with the absence of antibiotic resistance genes. Based on their phenotypic and genomic characteristics, L. fermentum Pom5 and P. pentosaceus Chi8 were identified as potential probiotic candidates for canines.

Antimicrobial activities of Zingiber officinale (ginger) and Curcuma longa (turmeric) on some reference bacterial strains

The antimicrobial activities of Zingiber officinale (Ginger) and Curcuma longa (turmeric) were studied on selected pathogens using standard microbiological techniques. Reference strains: Enterococcus durans ATCC 11576, Enterococcus faecalis ATCC 19433, Enterococcus faecium ATCC 35667, Enterococcus gallinarium ATCC 49573, Enterococcus hirae ATCC 49135, Pseudomonas aeruginosa ATCC 27853, Aeromonas hydrophila ATCC 7966, Acinetobacter baumanni ATCC 19606, Stenotrophomonas maltophilia ATCC 13637 and Escherichia coli WG5 were obtained from GI-Microbiology/Biotechnology Agriculture Research Council, Irene and Durban University of Technology, South Africa. Crude ethanolic extracts and partitioned fractions; dichloromethane, ethyl acetate, n-hexane and 1-butanol were also investigated. Antimicrobial activities of the ethanolic extracts of Z. officinale and C. longa showed zones of inhibition that ranged from 9 mm to 13 mm and 10 mm to 18 mm respectively against the test isolates. Z. officinale ethanolic extract showed no activities against Enterococcus gallinarium ATCC 49573 and Enterococcus hirae ATCC 49135 while C. longa ethanolic extract showed activities against all the test isolates. Various fractions showed inconsistent antimicrobial activities. The largest zone of inhibition was obtained from n-hexane (ZI= 22 mm) fraction of C. longa while Z. officinale crude extract showed zone of inhibition (ZI= 13) against all the tested isolates. Partitioned extracts showed 8-22 mm zone of inhibition with turmeric having the largest zone of inhibition. Activities in these extracts can be attributed to repertoire of phytochemical constituents, especially the Alkaloids and Flavonoids detected in them. These activities can be utilized for preservation purposes of food since both turmeric and ginger are edible natural spices.

Enterocin LD3 from Enterococcus hirae LD3 Inhibits the Growth of Salmonella entericasubsp. enterica serovar Typhimurium ATCC 13311 in Fruit Juice.

In order to prevent the growth of pathogens in food, bacteriocins produced by various probiotic lactic acid bacteria have been recognized as potential substitutes of chemical preservatives. In this study, enterocin LD3 was purified from the cell-free supernatant of a food isolate, Enterococcus hirae LD3 using multistep chromatography. In the fruit juice, lethal concentration (LC50) of enterocin LD3 was found to be 260µg/mL against Salmonella enterica subsp. enterica serovar Typhimurium ATCC 13311. The cells treated with enterocin LD3 were red colour indicating dead cells after propidium iodide staining, while untreated cells were found blue after staining with 4', 6-diamidino-2-phenylindole. The mechanism of cell killing was analyzed using infrared spectrum of cells treated with enterocin LD3 which was found altered in the range of 1,094.30 and 1,451.82cm-1 corresponding to nucleic acids and phospholipids, respectively. The morphology of target cells were severely ruptured and lysed as observed under electron microscopy. Thus, the present study suggested that enterocin LD3 showed bactericidal activity against Salm. enterica subsp. enterica serovar Typhimurium ATCC 13311 and may be applied as a bio-preservative for the safety of fruit juices.

Metagenomics and metagenome-assembled genomes mining of health benefits in jalebi batter, a naturally fermented cereal-based food of India

Jalebi is one of the oldest Indian traditional fermented wheat-based confectioneries. Since jalebi is prepared by natural fermentation, diverse microbial community is expected to play bio-functional activities. Due to limited studies, information on microbial community structure in jalebi is unknown. Hence, the present study is aimed to profile the microbial community in jalebi by shotgun metagenomics and also to predict putative probiotic and functional genes by metagenome-assembled genome (MAG). Bacteria were the most abundant domain (91.91%) under which Bacillota was the most abundant phylum (82%). The most abundant species was Lapidilactobacillus dextrinicus followed by several species of lactic acid bacteria, acetic acid bacteria including few yeasts. Lap. dextrinicus was also significantly abundant in jalebi when compared to similar fermented wheat-based sourdough. Additionally, Lap. bayanensis, Pediococcus stilesii, and yeast- Candida glabrata, Gluconobacter japonicus, Pichia kudriavzevii, Wickerhamomyces anomalus were only detected in jalebi, which are not detected in sourdough. Few viruses and archaea were detected with < 1 % abundance. In silico screening of genes from the abundant species was mined using both KEGG and EggNOG database for putative health beneficial attributes. Circular genomes of five high-quality MAGs, identified as Lapidilactobacillus dextrinicus, Enterococcus hirae, Pediococcus stilesii, Acetobacter indonesiensis and Acetobacter cibinongensis, were constructed separately and putative genes were mapped and annotated. The CRISPR/Cas gene clusters in the genomes of four MAGs except Acetobacter cibinongensis were detected. MAGs also showed several secondary metabolites. Since, the identified MAGs have different putative genes for bio-functional properties, this may pave the way to selectively culture the uncultivated putative microbes for jalebi production. We believe this is the first report on metagenomic and MAGs of jalebi.

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.

Long-Time Dynamics of Selected Molecular-Motor Components Using a Physics-Based Coarse-Grained Approach.

Molecular motors are essential for the movement and transportation of macromolecules in living organisms. Among them, rotatory motors are particularly efficient. In this study, we investigated the long-term dynamics of the designed left-handed alpha/alpha toroid (PDB: 4YY2), the RBM2 flagellum protein ring from Salmonella (PDB: 6SD5), and the V-type Na+-ATPase rotor in Enterococcus hirae (PDB: 2BL2) using microcanonical and canonical molecular dynamics simulations with the coarse-grained UNRES force field, including a lipid-membrane model, on a millisecond laboratory time scale. Our results demonstrate that rotational motion can occur with zero total angular momentum in the microcanonical regime and that thermal motions can be converted into net rotation in the canonical regime, as previously observed in simulations of smaller cyclic molecules. For 6SD5 and 2BL2, net rotation (with a ratcheting pattern) occurring only about the pivot of the respective system was observed in canonical simulations. The extent and direction of the rotation depended on the initial conditions. This result suggests that rotatory molecular motors can convert thermal oscillations into net rotational motion. The energy from ATP hydrolysis is required probably to set the direction and extent of rotation. Our findings highlight the importance of molecular-motor structures in facilitating movement and transportation within living organisms.

Antibiotic Susceptibility Patterns and Virulence-Associated Factors of Vancomycin-Resistant Enterococcal Isolates from Tertiary Care Hospitals.

This study explored the prevalence of multi-drug resistance and virulence factors of enterococcal isolates obtained from various clinical specimens (n = 1575) including urine, blood, pus, tissue, catheter, vaginal wash, semen, and endotracheal secretions. Out of 862 enterococcal isolates, 388 (45%), 246 (29%), 120 (14%), and 108 (13%) were identified as Enterococcus faecalis, Enterococcus faecium, Enterococcus durans, and Enterococcus hirae, respectively, using standard morphological and biochemical methods. The antibiotic resistance profile of all these enterococcal isolates was checked using the disc diffusion technique. High-level resistance was observed for benzylpenicillin (70%) and vancomycin (43%) among E. faecalis and E. faecium isolates, respectively. This study also revealed the prevalence of 'multi-drug resistance (resistant to 3 antibiotic groups)' among the vancomycin-resistant enterococcal strains, and this was about 11% (n = 91). The virulence determinants associated with vancomycin resistance (VR) were determined phenotypically and genotypically. About 70 and 39% of E. faecalis and E. faecium isolates showed to be positive for all four virulence factors (gelatinase, protease, hemolysin, and biofilm). Among the several virulence genes, gelE was the most common virulence gene with a prevalence rate of 76 and 69% among E. faecalis and E. faecium isolates, respectively. More than 50% of VRE isolates harbored other virulence genes, such esp, asa, ace, and cylA. Similarly, the majority of the VR enterococcal isolates (n = 88/91) harbored vanA gene and none of them harbored vanB gene. These results disclose the importance of VR E. faecalis and E. faecium and the associated virulence factors involved in the persistence of infections in clinical settings.

Degradation of indole via a two-component indole oxygenase system from Enterococcus hirae GDIAS-5

Animal farming copiously generates indoles, which contribute to odor and pose a challenge for deodorization. While biodegradation is widely accepted, there is a lack of suitable indole-degrading bacteria for animal husbandry. In this study, we aimed to construct genetically engineered strains with indole-degrading abilities. Enterococcus hirae GDIAS-5 is a highly efficient indole-degrading bacterium, which functions via a monooxygenase YcnE presumably contributes to indole oxidation. However, the efficiency of engineered Escherichia coli expressing YcnE for indole degradation is lower than that of GDIAS-5. To improve its efficacy, the underlying indole-degradation mechanisms in GDIAS-5 were analyzed. An ido operon that responds to a two-component indole oxygenase system was identified. In vitro experiments showed that the reductase component of YcnE, YdgI, can improve the catalytic efficiency. The reconstruction of the two-component system in E. coli exhibited higher indole removal efficiency than GDIAS-5. Furthermore, isatin, the key intermediate metabolite in indole degradation, might be degraded via a novel isatin-acetaminophen-aminophenol pathway involving an amidase whose coding gene is located near the ido operon. The two-component anaerobic oxidation system, upstream degradation pathway, and engineering strains investigated in this study provide important insights into indole degradation metabolism and offer efficient resources for achieving bacterial odor elimination.

Effect of the controlled fermented quinoa containing protective starter culture on technological characteristics of wheat bread supplemented with red lentil.

Selected antifungal lactic acid bacteria (LAB) isolated from mature spontaneous quinoa sourdough was used as potential starter culture to produce loaf wheat bread containing controlled fermented quinoa (CFQ) supplemented with red lentil (RL) flour. Phylogenetic evolutionary tree led to the identification of Enterococcus hirae as the selected LAB isolate. Furthermore, there was no significant difference (P > 0.05) between bread containing CFQ and control in terms of hardness. The highest loaf specific volume and overall acceptability were also observed in control sample and wheat bread containing CFQ + RL, respectively. Meanwhile, the rate of surface fungal growth on wheat bread enriched with CFQ was significantly lower than the other samples. In accordance with a non-linear multivariable model, positive and negative correlations were observed between porosity and specific volume (+ 0.79), and also specific volume and crumb hardness (- 0.70), respectively. Accordingly, CFQ can be used as bio-preservative to produce clean-label supplemented wheat bread.