41 research outputs found

    Update of the list of qualified presumption of safety (QPS) recommended microbiological agents intentionally added to food or feed as notified to EFSA 17: suitability of taxonomic units notified to EFSA until September 2022

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    The qualified presumption of safety (QPS) approach was developed to provide a regularly updated generic pre-evaluation of the safety of microorganisms, intended for use in the food or feed chains, to support the work of EFSA's Scientific Panels. The QPS approach is based on an assessment of published data for each agent, with respect to its taxonomic identity, the body of relevant knowledge and safety concerns. Safety concerns identified for a taxonomic unit (TU) are, where possible, confirmed at the species/strain or product level and reflected by ‘qualifications’. In the period covered by this Statement, new information was found leading to the withdrawal of the qualification ‘absence of aminoglycoside production ability’ for Bacillus velezensis. The qualification for Bacillus paralicheniformis was changed to ‘absence of bacitracin production ability’. For the other TUs, no new information was found that would change the status of previously recommended QPS TUs. Of 52 microorganisms notified to EFSA between April and September 2022 (inclusive), 48 were not evaluated because: 7 were filamentous fungi, 3 were Enterococcus faecium, 2 were Escherichia coli, 1 was Streptomyces spp., and 35 were taxonomic units (TUs) that already have a QPS status. The other four TUs notified within this period, and one notified previously as a different species, which was recently reclassified, were evaluated for the first time for a possible QPS status: Xanthobacter spp. could not be assessed because it was not identified to the species level; Geobacillus thermodenitrificans is recommended for QPS status with the qualification ‘absence of toxigenic activity’. Streptoccus oralis is not recommended for QPS status. Ogataea polymorpha is proposed for QPS status with the qualification ‘for production purposes only’. Lactiplantibacillus argentoratensis (new species) is included in the QPS list.info:eu-repo/semantics/publishedVersio

    Exploring multielement nanogranular coatings to forestall implant-related infections

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    Introduction: As we approach the post-antibiotic era, the development of innovative antimicrobial strategies that carry out their activities through non-specific mechanisms could limit the onset and spread of drug resistance. In this context, the use of nanogranular coatings of multielement nanoparticles (NPs) conjugated to the surface of implantable biomaterialsmight represent a strategy to reduce the systemicdrawbacks by locally confining the NPs effects against either prokaryotic or eukaryotic cells. Methods: In the present study, two new multielement nanogranular coatings combining Ag and Cu with either Ti or Mg were synthesized by a gas phase physical method and tested against pathogens isolated from periprosthetic joint infections to address their potential antimicrobial value and toxicity in an in vitro experimental setting. Results: Overall, Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli displayed a significantly decreased adhesion when cultured on Ti-Ag-Cu and Mg-Ag-Cu coatings compared to uncoated controls, regardless of their antibiotic resistance traits. A dissimilar behavior was observed when Pseudomonas aeruginosa was cultured for 30 and 120 minutes upon the surface of Ti-Ag-Cu and Mg-Ag-Cu-coated discs. Biofilm formation was mainly reduced by the active effect of Mg-Ag-Cu compared to Ti-Ag-Cu and, again, coatings had a milder effect on P. aeruginosa, probably due to its exceptional capability of attachment and matrix production. These data were further confirmed by the evaluation of bacterial colonization on nanoparticle-coated discs through confocal microscopy. Finally, to exclude any cytotoxic effects on eukaryotic cells, the biocompatibility of NPs-coated discs was studied. Results demonstrated a viability of 95.8% and 89.4% of cells cultured in the presence of Ti-Ag-Cu and Mg-Ag-Cu discs, respectively, when compared to negative controls. Conclusion: In conclusion, the present study demonstrated the promising antiadhesive features of both Ti-Ag-Cu and Mg-Ag-Cu coatings, as well as their action in hampering the biofilm formation, highlighting the safe use of the tested multielement families of nanoparticles as new strategies against bacterial attachment to the surface of biomedical implants

    Postbiotics for Preventing and Treating Common Infectious Diseases in Children: A Systematic Review

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    Postbiotics have recently been tentatively defined as bioactive compounds produced during a fermentation process (including microbial cells, cell constituents and metabolites) that supports health and/or wellbeing. Postbiotics are currently available in some infant formulas and fermented foods. We systematically reviewed evidence on postbiotics for preventing and treating common infectious diseases among children younger than 5 years. The PubMed, Embase, SpringerLink, and ScienceDirect databases were searched up to March 2019 for randomized controlled trials (RCTs) comparing postbiotics with placebo or no intervention. Seven RCTs involving 1740 children met the inclusion criteria. For therapeutic trials, supplementation with heat-killed Lactobacillus acidophilus LB reduced the duration of diarrhea (4 RCTs, n = 224, mean difference, MD, −20.31 h, 95% CI −27.06 to −13.57). For preventive trials, the pooled results from two RCTs (n = 537) showed that heat-inactivated L. paracasei CBA L74 versus placebo reduced the risk of diarrhea (relative risk, RR, 0.51, 95% CI 0.37-0.71), pharyngitis (RR 0.31, 95% CI 0.12-0.83) and laryngitis (RR 0.44, 95% CI 0.29-0.67). There is limited evidence to recommend the use of specific postbiotics for treating pediatric diarrhea and preventing common infectious diseases among children. Further studies are necessary to determine the effects of different postbiotics.</p

    Biofilm formation under industrially-relevant conditions.

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    Biofilms are considered to be one of the most prevalent and successful modes of life on Earth, and the prevailing lifestyle for microorganisms. Enabling bacteria to adapt to an incredibly diverse array of environments and extreme conditions, biofilms are a major contaminant of both medical and industrial settings. Indeed, approximately 80% of microbial infections are associated with biofilm formation, whilst the damage caused by biofilms in industry is estimated at between 2 – 3% of global GDP per annum. In this body of work, the effect of two industrially-relevant shear conditions on biofilm formation by the reference Pseudomonas aeruginosa (Ps. a.) strains PA01 and PA14 was investigated, as well as the effect of growth conditions and growth medium components on curli gene expression in E. coli K12 PHL644. The CBC biofilm reactor was used to model low and high shear conditions at 75 RPM and 350 RPM respectively, and biofilms grown over a time period of 96 hours. High levels of the intracellular second messenger c-di-GMP are regarded as the determining factor for Ps. a. sessility and progression of the biofilm phenotype, thus the c-di-GMP-responsive cdrA::gfp reporter was used to measure intracellular c-di-GMP levels of PA01 and PA14 under low and high shear conditions. Biofilms were analysed via confocal laser scanning microscopy and staining of extracellular DNA (eDNA) and the exopolysaccharides Psl and Pel, which are all form crucial components of a self-produced and protective extracellular matrix that surrounds and enmeshes Ps. a. within a biofilm. Under high shear at 350 RPM, intracellular c-di-GMP levels of initially adhered (at 24 hours) bacteria were increased, resulting in increased production of exopolysaccharides and formation of early aggregative structures. Shear conditions were shown to impact upon biofilm development and maturation of three-dimensional structures: crucially, mushroom-shaped macrocolonies, which are archetypal of Ps. a. biofilm formation, did not form under high shear. Under low shear at 75 RPM, Psl and Pel were organised into networks of fibre-like structures that penetrated throughout well-established basal biofilms (> 72 hours), which is in agreement with the work of others (with respect to Psl), but is a novel observation of Pel morphology as produced by PA14. The work presented in this thesis therefore provides further insight on the variety of Psl and Pel morphologies that exhibit different structures, spatial and temporal organisation, and function across PA01 and PA14 biofilms in response to either low or high shear conditions. Whilst similarities were observed between the two strains, PA01 and PA14 exhibited distinct responses to the imposed shear regime, in terms of initial surface colonisation, time taken for mature structures to emerge, and exopolysaccharide production. Biofilms produced by E. coli PHL644 were grown using the Duran bottle model, via a method previously developed by the Overton laboratory. High levels of the transcriptional regulator CsgD are regarded as ‘master switch’ that determines biofilm formation in E. coli, thus the CsgD-responsive csgB::gfp reporter was used to measure curli gene expression in response to growth in LB broth (a rich medium) versus M63+ minimal medium, different concentrations of glucose (at 0 mM, 1 mM, 10 mM and 100 mM), and incubation at different temperatures (at 25 oC, 28 oC, 30 oC and 37 oC), and identify parameters which resulted in maximal expression of curli. Planktonic cell samples were taken from the tops of the Duran bottles, and sedimented cell samples taken from the bottom of the Duran bottles for comparative analysis of growth via spectrophotometry at OD600 and csgB::gfp fluorescence by flow cytometry. Curli gene expression was found to be highest in cultures grown in M63+ minimal medium, with a glucose concentration of 10 mM and at an incubation temperature of 30 oC, which is in agreement with comparable studies in the literature. Of interest was the fact that an inverse relationship between biomass concentration (as defined by OD600 values) and csgB::gfp fluorescence was observed. Curli gene expression in sedimented cell samples was consistently lower than that of planktonic cell cultures across all experimental subsets, suggesting that planktonic cells are physically more capable of surface attachment, and curli expression may be downregulated when in a sediment; exemplifying the importance and function of curli as the initial adhesin of E. coli K12. Overall, this body of work concludes that different shear conditions can impact upon Ps. a. biofilm development and induce distinct organisation of the ECM, and that the CBC biofilm reactor is a suitable experimental model for assessing the impact of turbulent flow regimes, akin to those experienced in industrial manufacturing plants, on biofilm formation and composition. Additionally, this body of work also demonstrated that the Duran bottle model is also a suitable method for biofilm formation, and for investigating the effect of a wide array of growth conditions on E. coli K12 biofilm formation and curli gene expression. Parameters that resulted in maximal curli gene expression in E. coli K12 PHL644 cultures grown via the Duran bottle method under the conditions tested were identified, and could be further used to optimise production of a physically robust E. coli biofilm for use in biocatalysis or certain industrial settings

    Oral Microbial Communities and Oral Health

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    More than 700 species of bacteria are involved in the oral cavity. Specific pathogenic bacteria have been focused on as pathogenic bacteria for oral disease: dental caries and periodontal disease. However, these pathogenic bacteria occupy a tiny fraction of the overall oral microbiome. A high throughput genomic analysis system was developed. This technology innovation enables analysis of the whole bacteria. It is hypothesized that disturbance of the oral microbiome, so-called dysbiosis, leads to the development of some diseases. This book provides knowledge concerning recent advances in the oral microbiome for researchers as well as dental clinicians

    Antimicrobial Materials with Medical Applications

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    This Special Issue of the International Journal of Molecular Science comprises a comprehensive study on “Antimicrobial Materials with Medical Applications”. The Special Issue has been inspired by the great progress made in the development of new antimicrobial materials that go beyond the resistance of microbes to modern antibiotics. It covers a selection of recent research and review articles in the field of antimicrobial materials and their medical applications. Moreover, it also provides an overview of this increasingly diverse field, presenting recent developments and the latest research, with particular emphasis on new antimicrobial surfaces, medical devices, contact lens, package materials, etc

    A Brief Review of Local Bacteriotherapy for Preventing Respiratory Infections

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    Recurrent respiratory infections (RRIs) account for relevant economic and social implications and significantly affect family life. Local Bacteriotherapy (LB) represents an innovative option in preventing RRIs. Local bacteriotherapy consists of administering “good” and safe bacteria (probiotics) by nasal or oral route. In particular, two strains (Streptococcus salivarius 24SMB and Streptococcus oralis 89a) are commonly used. The present article presents and discusses the literature concerning LB. Infections of airways include the upper and lower respiratory tract. A series of clinical trials investigated the preventive role of LB in preventing upper and lower RIs. These studies demonstrated that LB safely reduced the prevalence and severity of RIs, the use of antibiotics, and absences from school. Therefore, Local Bacteriotherapy may be considered an interesting therapeutic option in RRI prevention

    Nutraceutical, Nutrition Supplements and Human Health

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    This Special Issue of Nutrients on "Nutraceutical, Nutrition Supplements, and Human Health" provides readers with contemporary knowledge on the role of functional foods, dietary supplements, and nutraceuticals in improving overall health and preventing chronic diseases. Various renowned international scientists, physicians, and other healthcare professionals have contributed to this compendium of excellent laboratory and clinical studies. The manuscripts provide evidence-based knowledge of nutritional compounds/functional food to improve many health conditions, including metabolic disorders, cardiovascular disease, muscle metabolism, obesity, neurological disorders, infectious diseases, aging, and cancer. All contributions were thoroughly peer-reviewed by a distinguished panel of scientists, and only highly ranked manuscripts were included to ensure the quality of contents. This book is an excellent resource for academic personnel and students in nutrition research, dietitians, physicians, and consumers

    Corynebacterium species inhibit Streptococcus pneumoniae colonization and infection of the mouse airway

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    The stability and composition of the airway microbiome is an important determinant of respiratory health. Some airway bacteria are considered to be beneficial due to their potential to impede the acquisition and persistence of opportunistic bacterial pathogens such a
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