Prolonged use of old dentures: A qualitative study with Brazilian older adults.

OBJECTIVE: To explore older adults' perceptions, motivations and reasons for using and not replacing old and worn complete dentures over prolonged periods. MATERIALS AND METHODS: In-depth, semi-structured interviews were conducted with Brazilian edentulous older adults who were wearing complete dentures which were at least 20 years old. A purposive sampling method was used to recruit participants from an existing waiting list of those referred to a hospital clinic for new dentures. The interviews were video-recorded, transcribed verbatim and analysed using thematic analysis. RESULTS: Sixty-two individuals were assessed and nine were included in the study, aged from 61 to 77 years (mean = 65.4), with seven (77.8%) of them women. The reported time using their current dentures ranged from 22 to 45 years (mean = 28). Content analysis revealed three main themes: the perception of the current dentures' condition after prolonged use; reasons for the prolonged use and non-replacement; and unsuccessful attempts to replace the dentures. Overall, participants acknowledged the poor condition of their dentures and did recognise the need for replacement. Several factors had prompted them to delay or temporarily forego replacement, with financial constraints being the main barrier. Some reported failed attempts to replace the dentures in the past years or months; however, challenging adaptation to the new prostheses led to them reverting back to their old dentures as a fallback solution. CONCLUSION: Factors influencing prolonged denture use in older adults include a complex interplay of financial aspects, treatment awareness, access and personal factors. Dental professionals can play a pivotal role in promoting timely denture adjustment or replacement by addressing these factors through patient education and personalised care.

Evaluating the potential of Pediococcus pentosaceus as a biocontrol agent against tenuazonic acid-producing Alternaria alternata on livestock feeds.

AIMS: This study aims to demonstrate the potential of the lactic acid bacteria (LAB) Pediococcus pentosaceus LBM18 against the mycotoxin-producing Alternaria alternata TEF-1A and highlight its application as an effective grain silage inoculant to control mycotoxin contamination. METHODS AND RESULTS: The antifungal properties of Ped. pentosaceus lyophilized (PPL) were assessed by evaluating its effect on A. alternata TEF-1A grown in a corn silage-based medium, which included morphological changes by Scanning Electron Microscopy (SEM) observations, growth rate, conidia production assays, and inhibition of Tenuazonic acid (TeA) production by high-performance liquid chromatography (HPLC-MS/MS) analyses. Furthermore, TeA biosynthesis was monitored for changes at the molecular level by PKS gene expression. The growth and sporulation processes of A. alternata TEF-1A were affected by Ped. pentosaceus LBM18 in a concentration-dependent manner. Moreover, a significant inhibition of TeA production (74.3%) and the transcription level of the PKS gene (42.9%) was observed. CONCLUSIONS: Ped. pentosaceus is one of the promising LAB to be applied as an inoculant for corn silage preservation, aiming to inhibit mycotoxigenic fungi growth and their mycotoxin production. SIGNIFICANCE AND IMPACT OF THE STUDY: Ped. pentosaceus could be used as an inoculant to reduce fungal and mycotoxins contamination in grain silage production.

Pulmonary embolism and COVID-19: A comparative analysis of different diagnostic models performance.

OBJECTIVE: Pulmonary embolism (PE) is a common complication of SARS-CoV-2 infection. Several diagnostic prediction rules based on pretest probability and D-dimer have been validated in non-COVID patients, but it remains unclear if they can be safely applied in COVID-19 patients. We aimed to compare the diagnostic accuracy of the standard approach based on Wells and Geneva scores combined with a standard D-dimer cut-off of 500 ng/mL with three alternative strategies (age-adjusted, YEARS and PEGeD algorithms) in COVID-19 patients. METHODS: This retrospective study included all COVID-19 patients admitted to the Emergency Department (ED) who underwent computed tomography pulmonary angiography (CTPA) due to PE suspicion. The diagnostic prediction rules for PE were compared between patients with and without PE. RESULTS: We included 300 patients and PE was confirmed in 15%. No differences were found regarding comorbidities, traditional risk factors for PE and signs and symptoms between patients with and without PE. Wells and Geneva scores showed no predictive value for PE occurrence, whether a standard or an age-adjusted cut-off was considered. YEARS and PEGeD algorithms were associated with increased specificity (19% CTPA reduction) but raising non-diagnosed PE. Despite elevated in all patients, those with PE had higher D-dimer levels. However, incrementing thresholds to select patients for CTPA was also associated with a substantial decrease in sensitivity. CONCLUSION: None of the diagnostic prediction rules are reliable predictors of PE in COVID-19. Our data favour the use of a D-dimer threshold of 500 ng/mL, considering that higher thresholds increase specificity but limits this strategy as a screening test.

Glutaminase-free L-asparaginase production by Leucosporidium muscorum isolated from Antarctic marine-sediment.

L-asparaginase (ASNase) is an essential drug in the treatment of acute lymphoblastic leukemia (ALL). Commercial bacterial ASNases increase patient survival, but the consequent immunological reactions remain a challenge. Yeasts ASNase is closer to human congeners and could lead to lower side effects. Among 134 yeast strains isolated from marine-sediments in King George Island, Antarctica, nine were L-asparaginase producing yeasts and glutaminase-free. Leucosporidium muscorum CRM 1648 yielded the highest ASNase activity (490.41 U.L-1) and volumetric productivity (5.12 U.L-1 h-1). Sucrose, yeast extract and proline were the best carbon and nitrogen sources to support growth and ASNase production. A full factorial design analysis pointed the optimum media condition for yeast growth and ASNase yield: 20 g L-1 sucrose, 15 g L-1 yeast extract and 20 g L-1 proline, which resulted in 4582.5 U L-1 and 63.64 U L-1 h-1 of ASNase and volumetric productivity, respectively. Analysis of temperature, pH, inoculum and addition of seawater indicated the best condition for ASNase production by this yeast: 12-15 °C, pH 5.5-6.5 and seawater >25% (v/v). Inoculum concentration seems not to interfere. This work is pioneer on the production of ASNase by cold-adapted yeasts, highlighting the potential of these microbial resources as a source of glutaminase-free L-asparaginase for commercial purposes.

Buffalo milk increases viability and resistance of probiotic bacteria in dairy beverages under in vitro simulated gastrointestinal conditions.

Probiotic dairy beverages prepared from buffalo and cow milks with different levels of whey (0, 25, and 50%) were evaluated for kinetic fermentation parameters, protein and fat contents, post-acidification profile, viability of Streptococcus thermophilus, Lactobacillus bulgaricus, and Lactobacillus acidophilus during 21 d of refrigerated storage, and resistance to in vitro gastrointestinal conditions. Progressive acidification that occurred during storage of all dairy products was reduced in the presence of whey. Lactic acid bacteria showed viable cell counts at the end of shelf life, with the highest values (7.33 to 8.83 log cfu/mL) detected in buffalo dairy products. Compared with fermented cow milk products, those made with buffalo milk showed better bacterial viability during in vitro simulated gastrointestinal digestion, which suggests a beneficial protective effect on human microbiome.

Understanding the interactions of imidazolium-based ionic liquids with cell membrane models.

Cell membrane models have been used to evaluate the interactions of various imidazolium-based ionic liquids (ILs) with Langmuir monolayers of two types of phospholipids and cholesterol. Data from surface pressure isotherms, Brewster angle microscopy (BAM) and polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS) pointed to significant effects on the monolayers of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and cholesterol, used to mimic the membranes of eukaryotic cells, for ILs containing more than 6 carbon atoms in the alkyl chain (i.e. n > 6). For ILs with less hydrophobic tails (n ≤ 6) and low concentrations, the effects were almost negligible, therefore, such ILs should not be toxic to eukaryotic cells. The hydrophobicity of the anion was also proved to be relevant, with larger impact from ILs containing tetrafluoroborate ([BF4]-) than chloride (Cl-). Molecular dynamics simulations for DPPC monolayers at the surface of aqueous solutions of alkylimidazolium chloride ([Cnmim]Cl) confirm the penetration of the IL cations with longer alkyl chains into the phospholid monolayer and provide information on their location and orientation within the monolayer. For monolayers of dipalmitoylphosphatidyl glycerol (DPPG), which is negatively charged like bacteria cell membranes, the ILs induced much larger effects. Similarly to the results for DPPC and cholesterol, effects increased with the number of carbon atoms in the alkyl chain and with a more hydrophobic anion [BF4]-. Overall, the approach used can provide relevant information of molecular-level interactions behind the toxicity mechanisms and support the design of (quantitative) structure-activity relationship models, which may help design more efficient and environmentally friendly ILs.

Comparison of the accuracy of four diagnostic prediction rules for pulmonary embolism in patients admitted to the emergency department.

INTRODUCTION AND OBJECTIVES: Ruling out pulmonary embolism (PE) through a combination of clinical assessment and D-dimer level can potentially avoid excessive use of computed tomography pulmonary angiography (CTPA). We aimed to compare the diagnostic accuracy of the standard approach based on the Wells and Geneva scores combined with a standard D-dimer cut-off (500 ng/ml), with three alternative strategies (age-adjusted and the YEARS and PEGeD algorithms) in patients admitted to the emergency department (ED) with suspected PE. METHODS: Consecutive outpatients admitted to the ED who underwent CTPA due to suspected PE were retrospectively assessed. Sensitivity, specificity, positive and negative predictive values, likelihood ratios and diagnostic odds ratios were calculated and compared between the different diagnostic prediction rules. RESULTS: We included 1402 patients (mean age 69±18 years, 54% female), and PE was confirmed in 25%. Compared to the standard approach (p<0.001), an age-adjusted strategy increased specificity with a non-significant decrease in sensitivity only in patients older than 70 years. Compared to the standard and age-adjusted approaches, the YEARS and PEGeD algorithms had the highest specificity across all ages, but were associated with a significant decrease in sensitivity (p<0.001), particularly in patients aged under 60 years (sensitivity of 81% in patients aged between 51 and 60 years). CONCLUSION: Compared to the standard approach, all algorithms were associated with increased specificity. The age-adjusted strategy was the only one not associated with a significant decrease in sensitivity compared to the standard approach, enabling CTPA requests to be reduced safely.

The fate of spinal arteries after the stent-assisted balloon-induced intimal disruption and relamination in aortic dissection repair technique: a case series.

Objective: We evaluated the patency of the spinal arteries (intercostal and lumbar) after the STABILISE (stent-assisted balloon-induced intimal disruption and relamination in aortic dissection repair) technique. Methods: A retrospective analysis of all patients with aortic dissection treated with the STABILISE technique between April 2018 and July 2021 was performed. Imaging analysis of the spinal cord vascular supply was accomplished using multiplanar and maximum intensity projection reconstructed images of pre- and postoperative computed tomography angiograms at 1 month, 12 months, and annually thereafter. Results: Twelve patients were treated for complicated aortic dissection. Primary technical success was 100% and mid-term clinical success, at a mean follow-up of 27 ± 12 months, was 90%. No cases of spinal cord ischemia were identified. One patient died after 1 year (non-aortic related), and one patient was lost to follow-up. A significant decrease was found in the mean number of patent spinal arteries in the stent graft area at 1 month (P < .001), 1 year (P < .001), and 2 years (P = .004). However, no significant reduction was found in the number of spinal arteries in either the bare metal stented or nonstented aorta (P > .05). Conclusions: Use of the STABILISE technique decreased intercostal artery patency in the thoracic stent graft area, but spinal artery patency was not significantly affected by the bare metal stent nor its aggressive ballooning. These findings constitute a step toward a better understanding of the safety of this technique.

Enhanced production of N-acetyl-glucosaminidase by marine Aeromonas caviae CHZ306 in bioreactor.

N-Acetyl-glucosaminidases (GlcNAcases) are exoenzymes found in a wide range of living organisms, which have gained great attention in the treatment of disorders related to diabetes, Alzheimer's, Tay-Sachs', and Sandhoff's diseases; the control of phytopathogens; and the synthesis of bioactive GlcNAc-containing products. Aiming at future industrial applications, in this study, GlcNAcase production by marine Aeromonas caviae CHZ306 was enhanced first in shake flasks in terms of medium composition and then in bench-scale stirred-tank bioreactor in terms of physicochemical conditions. Stoichiometric balance between the bioavailability of carbon and nitrogen in the formulated culture medium, as well as the use of additional carbon and nitrogen sources, played a central role in improving the bioprocess, considerably increasing the enzyme productivity. The optimal cultivation medium was composed of colloidal α-chitin, corn steep liquor, peptone A, and mineral salts, in a 5.2 C:N ratio. Optimization of pH, temperature, colloidal α-chitin concentration, and kLa conditions further increased GlcNAcase productivity. Under optimized conditions in bioreactor (i.e., 34 °C, pH 8 and kLa 55.2 h-1), GlcNAcase activity achieved 173.4 U.L-1 after 12 h of cultivation, and productivity no less than 14.45 U.L-1.h-1 corresponding to a 370-fold enhancement compared to basal conditions.

Antimicrobial Activity of Peptides Produced by Lactococcus lactis subsp. lactis on Swine Pathogens.

Swine production is of great importance worldwide and has huge economic and commercial impact. Due to problems with bacterial infection, the use of antimicrobials has increased in the last decades, particularly in Latin America and Asia. This has led to concerns about antimicrobial resistance, which poses risks to human health and the environment. The use of probiotic organisms has been proposed as an alternative to this use, as these beneficial bacteria can produce antimicrobial peptides, such as bacteriocins, which allow the induction of inhibitory effects against pathogenic microorganisms. Among probiotics, some bacteria stand out with the inhibition of animal pathogens. The bacteriocin-like inhibitory substances (BLISs) of Lactococcus lactis subsp. lactis strain L2, present in its cell-free supernatant, were tested against pathogenic strains isolated from pig samples, such as Escherichia coli, Salmonella enterica, Streptococcus suis, Streptococcus dysgalactiae, Staphylococcus hyicus, and Enterococcus faecalis. Compounds secreted by L. lactis L2 have been shown to inhibit the growth of some pathogenic species, particularly Gram-positive bacteria, with S. suis being the most prominent. Antimicrobial peptides with a molecular size of 500-1160 Daltons were isolated from BLISs. The results highlight the potential of L. lactis BLISs and its peptides as natural antimicrobials for use in the food industry and to reduce the use of growth promoters in animal production.

Tracking new insights into antifungal and anti-mycotoxigenic properties of a biofilm forming Pediococcus pentosaceus strain isolated from grain silage.

The present study offers detailed insights into the antifungal and anti-mycotoxigenic potential of a biofilm forming lactic acid bacterium (Pediococcus pentosaceus) against one atoxigenic (Aspergillus flavus) and two toxigenic (Aspergillus nomius and Fusarium verticillioides) fungal strains. The antifungal effect of P. pentosaceus LBM18 strain was initially investigated through comparative analysis of fungi physiology by macroscopic visual evaluations and scanning electron microscopy examinations. The effects over fungal growth rate and asexual sporulation were additionally accessed. Furthermore, analytical evaluations of mycotoxin production were carried out by HPLC-MS/MS to provide insights on the bacterial anti-mycotoxigenic activity over fungal production of the aflatoxins B1, B2, G1 and G2 as well as fumonisins B1 and B2. Finally, reverse transcription quantitative real-time PCR (RT-qPCR) analysis was employed at the most effective bacterial inoculant concentration to evaluate, at the molecular level, the down-regulation of genes aflR, aflQ and aflD, related to the biosynthesis of aflatoxins by the strain of Aspergillus nomius. The effects over mycotoxin contamination were thought to be result of a combination of several biotic and abiotic factors, such as interaction between living beings and physical-chemical aspects of the environment, respectively. Several possible mechanisms of action were addressed along with potentially deleterious effects ascribing from P. pentosaceus misuse as biopesticide, emphasizing the importance of evaluating lactic acid bacteria safety in new applications, concentrations, and exposure scenarios.

Effects of gamma radiation on the vector competence of Aedes aegypti (diptera: Culicidae) to transmit Zika virus.

One of the limitations of the Sterile Insect Technique (SIT), conventionally performed by ionizing radiation, regards separating males from females, which is not 100% effective. Some irradiated females may be released together with males in the field at SIT. The present study aimed to evaluate the influence of ionizing radiation on the ability of Aedes aegypti mosquitoes to transmit the Zika virus after exposing female pupae to a 40 Gy of gamma radiation. The results suggest that the genetic damage induced by exposure of females to this dose level promotes their total sterility, but it does not influence their vector competence. However, our data point out that ionizing radiation may decrease the proportion of infective mosquitoes.

Bacteriocin-like inhibitory substances production by Enterococcus faecium 135 in co-culture with Ligilactobacillus salivarius and Limosilactobacillus reuteri.

The use of lactic acid bacteria (LAB) and probiotic cultures in the breeding of animals such as poultry and swine are quite common. It is known that those strains can produce bacteriocins when grown in pure culture. However, the production of bacteriocin using co-culture of microorganisms has not been much studied so far. The present study contributes with innovation in this area by embracing the production of bacteriocin-like inhibitory substances (BLIS) by a newly isolated strain of Enterococcus faecium 135. Additionally, the co-cultivation of this strain with Ligilactobacillus salivarius and Limosilactobacillus reuteri was also investigated. The antimicrobial activity of the produced BLIS was evaluated against Listeria monocytogenes, Listeria innocua, Salmonella enterica, and Salmonella enterica serovar Typhimurium using two methods: turbidimetric and agar diffusion. In addition, the presence of enterocin genes was also evaluated. The BLIS produced showed a bacteriostatic effect against the bio-indicator strains, and the highest antimicrobial activities expressed by arbitrary units per mL (AU/mL) were obtained against L. monocytogenes in monoculture (12,800 AU/mL), followed by the co-culture of E. faecium with Limosilactobacillus reuteri (400 AU/mL). After concentration with ammonium sulfate, the antimicrobial activity raised to 25,600 AU/mL. Assays to determine the proteinaceous nature of the BLIS showed susceptibility to trypsin and antimicrobial activity until 90 °C. Finally, analysis of the presence of structural genes of enterocins revealed that four enterocin genes were present in E. faecium 135. These results suggest that BLIS produced by E. faecium 135 has potential to be a bacteriocin and, after purification, could potentially be used as an antimicrobial agent in animal breeding.

Comparison of 5 acute pulmonary embolism mortality risk scores in patients with COVID-19.

OBJECTIVE: Pulmonary embolism (PE) is a common complication of SARS-CoV-2 infection. We aimed to explore the short-term outcomes among patients with acute PE and COVID-19 and to further determine and compare the performance of the different prognostic scores (PESI, sPESI, BOVA, FAST and ESC scores) for risk-stratification in this scenario. METHODS: Retrospective single-centre study of 85 patients with SARS-CoV-2 infection and PE admitted to the Emergency Department (ED). The diagnostic accuracy of each above-mentioned prognostic score was calculated post hoc, and their discriminative power was evaluated through an AUC curve. RESULTS: Among the 85 patients, all-cause death occurred within 7 days for 6 patients (7.1%) and within 30 days for 14 patients (16.5%). Despite being older and having a higher percentage of altered mental status on presentation, non-survivors patients did not differ from survivors regarding comorbidities, traditional risk factors for venous thromboembolism and signs and symptoms at the ED presentation.Each risk stratification tool had modest discriminative power for 7-day mortality (AUC range, 0.601-0.730) with slightly lower discrimination for 30-day mortality (AUC range, 0.543-0.638). The pair-wise comparison of ROC curves showed that PESI had better predictive value for short-term mortality than ESC score (z test = 3.92, p = 0.001) and sPESI (z test = 2.43, p = 0.015); there is no significant difference between PESI and BOVA score (z test = 1.05, p = 0.295) and FAST score (z test = 0.986, p = 0.324). CONCLUSION: The most common risk-stratification tools for PE had modest discriminative power to predict short-term mortality in patients with acute PE and COVID-19.

Effects of gamma radiation on the reproductive viability of Aedes aegypti and its descendants (Diptera: Culicidae).

This work evaluated the genetic damage in descendants of male pupae of Aedes (Stegomyia) aegypti (Diptera: Culicidae) separately exposed to 20, 30, and 40 Gy of gamma radiation in the context of Sterile Insect Technique (SIT). Despite the transmission of the dominant lethal mutation, the employed dose levels did not promote a marked reduction in adult mosquito emergence and fertility. This study emphasized that semi-sterilizing doses < 50 Gy for SIT of Aedes aegypti are not recommended.

Prognostic Accuracy of the Modified CHA2DS2-VASc Score in COVID-19 Patients Admitted to the Emergency Department Due to Clinical Worsening.

INTRODUCTION: Risk factors comprising the CHA2DS2VASc score are recognized as risk factors for venous thromboembolism and mortality in COVID-19 patients. A modified CHA2DS2VASc score (M-CHA2D2VASc), developed by changing gender criteria from female to male, has been proposed to predict in-hospital mortality in COVID-19 patients. The aim of this study was to evaluate the prognostic accuracy of M-CHA2D2VASc for adverse clinical outcomes and short-term mortality in COVID-19 patients admitted to the Emergency Department. MATERIAL AND METHODS: Retrospective study of patients admitted to the ED who underwent computed tomography pulmonary angiography due to suspected pulmonary embolism or clinical worsening. Patients were stratified into three M-CHA2DS2-VASc risk-categories: low (0 - 1 points), intermediate (2 - 3 points) and high-risk (≥ 4 points). RESULTS: We included 300 patients (median age 71 years, 59% male). The overall mortality was 27%. The M-CHA2DS2-VASc score was higher in non-survivors compared to survivors [4 (IQR:3 - 5) vs 2 (IQR: 1 - 4), respectively, p < 0.001). The M-CHA2DS2-VASc score was identified as an independent predictor of mortality in a multivariable logistic regression model (OR 1.406, p = 0.007). The Kaplan-Meier survival curves showed that the M-CHA2DS2-VASc score was associated with short-term mortality (log-rank test < 0.001), regardless of hospitalization (log-rank test p < 0.001 and p = 0.007, respectively). The survival proportion was 92%, 80% and 63% in the lower, intermediate, and higher risk-groups. As for the risk-categories, no difference was found in pulmonary embolism, Intensive Care Unit admission, and invasive mechanical ventilation. DISCUSSION: This is the first study to validate M-CHA2DS2-VASc score as a predictor of short-term mortality in patients admitted to the Emergency Department. CONCLUSION: The M-CHA2DS2-VASC score might be useful for prompt risk-stratification in COVID-19 patients during admission to the Emergency Department.

Introdução: O score CHA2DS2VASc engloba variáveis reconhecidas como fatores de risco para tromboembolismo venoso e mortalidade nos doentes com COVID-19. O score CHA2DS2VASc modificado (M-CHA2DS2-VASc), criado pela alteração do critério de género de feminino para masculino, foi proposto como preditor da mortalidade intra-hospitalar nestes doentes. O objetivo deste trabalho foi avaliar o valor prognóstico do M-CHA2DS2-VASc como preditor de eventos adversos e mortalidade a curto-prazo nos doentes com COVID-19 admitidos no Serviço de Urgência. Material e Métodos: Análise retrospetiva de doentes admitidos no Serviço de Urgência que realizaram tomografia computorizada pulmonar com administração de contraste por agravamento clínico e/ou suspeita de embolia pulmonar. Definiram-se três categorias de risco M-CHA2DS2-VASc: baixo, intermédio e alto (0 - 1; 2 - 3 e ≥ 4 pontos, respectivamente). Resultados: Incluíram-se 300 doentes (idade mediana: 71 anos, 59% homens). A mortalidade global foi 27%. O M-CHA2DS2-VASc foi maior em não sobreviventes [4 (IQR: 3 - 5) vs 2 (IQR: 1 - 4), p < 0,001) e constituiu um preditor independente de mortalidade numa análise multiparamétrica (OR: 1.406, p = 0,007). As curvas de sobrevivência demonstraram a associação do M-CHA2DS2-VASc com a mortalidade a curto-prazo (log-rank test < 0,001), independentemente dos doentes serem hospitalizados ou não (log-rank test p < 0,001 e p = 0,007, respetivamente). A taxa de sobrevida foi de 92%, 80% e 63% nos grupos de baixo, intermédio e alto risco. De acordo com as categorias de risco, não foram encontradas diferenças na incidência de embolia pulmonar, admissão em Cuidados Intensivos e ventilação mecânica invasiva. Discussão: Este é o primeiro estudo a validar o M-CHA2DS2-VASc como preditor de mortalidade a curto prazo na admissão no Serviço de Urgência. Conclusão: O M-CHA2DS2-VASc pode ser útil para estratificação de risco nos doentes com COVID-19 admitidos no Serviço de Urgência.

Pan-genomic and comparative analysis of Pediococcus pentosaceus focused on the in silico assessment of pediocin-like bacteriocins.

Bacteriocins are antimicrobial peptides produced by different species of bacteria, especially the Gram-positive lactic acid bacteria (LAB). Pediococcus pentosaceus is widely applied in the industry and stands out as Bacteriocin-Like Inhibitory Substances (BLIS) producer known to inhibit pathogens commonly considered a concern in the food industries. This study aimed to perform in silico comparisons of P. pentosaceus genomes available in the public GenBank database focusing on their pediocin-like bacteriocins repertoire. The pan-genome analysis evidenced a temporal signal in the pattern of gene gain and loss, supporting the hypothesis that the complete genetic repertoire of this group of bacteria is still uncovered. Thirteen bacteriocin genes from Class II and III were predicted in the accessory genome. Four pediocin-like bacteriocins (54% of the detected bacteriocin repertoire) and their accompanying immunity genes are highlighted; penocin A, coagulin A, pediocin PA-1, and plantaricin 423. Additionally, in silico, modeling of the pediocin-like bacteriocins revealed different configurations of the helix motif compared to other physically determined pediocin-like structures. Comparative and phylogenomic analyses support the hypothesis that a dynamic mechanism of bacteriocin acquisition and purging is not dependent on the bacterial isolation source origin. Synteny analysis revealed that while coagulin A, pediocin PA-1, and Plantaricin 423 loci are associated with insertion sequences mainly from the IS30 family and are likely of plasmid origin, penocin A lies in a conserved chromosomal locus. The results presented here provide insights into the unique pediocin-like bacteriocin peptide fold, genomic diversity, and the evolution of the bacteriocin genetic repertoire of P. pentosaceus, shedding new insights into the role of these biomolecules for application in inhibiting bacterial pathogens, and suggesting that prospecting and sequencing new strains is still an alternative to mining for new probiotic compounds.

Use of Probiotic Bacteria and Bacteriocins as an Alternative to Antibiotics in Aquaculture.

In addition to their use in human medicine, antimicrobials are also used in food animals and aquaculture, and their use can be categorized as therapeutic against bacterial infections. The use of antimicrobials in aquaculture may involve a broad environmental application that affects a wide variety of bacteria, promoting the spread of bacterial resistance genes. Probiotics and bacteriocins, antimicrobial peptides produced by some types of lactic acid bacteria (LAB), have been successfully tested in aquatic animals as alternatives to control bacterial infections. Supplementation might have beneficial impacts on the intestinal microbiota, immune response, development, and/or weight gain, without the issues associated with antibiotic use. Thus, probiotics and bacteriocins represent feasible alternatives to antibiotics. Here, we provide an update with respect to the relevance of aquaculture in the animal protein production sector, as well as the present and future challenges generated by outbreaks and antimicrobial resistance, while highlighting the potential role of probiotics and bacteriocins to address these challenges. In addition, we conducted data analysis using a simple linear regression model to determine whether a linear relationship exists between probiotic dose added to feed and three variables of interest selected, including specific growth rate, feed conversion ratio, and lysozyme activity.

Beneficial effects of probiotics on the pig production cycle: An overview of clinical impacts and performance.

In pig nutrition, antibiotics are used to promote growth and/or to treat diseases in order to improve animal performance. However, due to the potential risk of cross selective pressure for antibiotic resistance among bacterial pathogens, the development of new nutritional additives is needed. Among them, probiotics are of great interest since they could improve the immune response, maintain animal intestinal health, and improve nutritional efficiency. Studies with probiotics have also demonstrated their antimicrobial effects on several pathogenic strains, emphasizing that the form of administration can enhance the beneficial effects. In view of the promising advances in probiotic research, it is opportune to highlight their capacity to modulate health and improve performance at all stages of pig production. Therefore, in this review, we will discuss the benefits of probiotics on physiological, immunological, and clinical aspects during different stages of the pig's life cycle. Specifically, probiotics improve performance during pregnancy, parturition and lactation in sows, they can improve immunohematological parameters and defenses in the growing phase, they can influence the quality of meat in the finishing phase and can also help in the reduction of environmental pollutants.

Bacteriocinogenic probiotic bacteria isolated from an aquatic environment inhibit the growth of food and fish pathogens.

The conditions of aquatic environments have a great influence on the microbiota of several animals, many of which are a potential source of microorganisms of biotechnological interest. In this study, bacterial strains isolated from aquatic environments were bioprospected to determine their probiotic profile and antimicrobial effect against fish and food pathogens. Two isolates, identified via 16S rRNA sequencing as Lactococcus lactis (L1 and L2) and one as Enterococcus faecium 135 (EF), produced a bacteriocin-like antimicrobial substance (BLIS), active against Listeria monocytogenes, Salmonella Choleraesuis and Salmonella Typhimurium. Antimicrobial activity of BLIS was reduced when exposed to high temperatures and proteolytic enzymes (trypsin, pepsin, papain and pancreatin). All strains were sensitive to 7 types of antibiotics (vancomycin, clindamycin, streptomycin, gentamicin, chloramphenicol, rifampicin and ampicillin), exhibited a high rate of adherence to Caco-2 cells and expressed no hemolysin and gelatinase virulence factors. EF showed some resistance at pH 2.5 and 3.0, and L2/EF showed higher resistance to the action of bile salts. Finally, the presence of bacteriocin genes encoding for proteins, including Nisin (L1 and L2), Enterocin A, B, P, and Mundticin KS (EF) was detected. The molecular and physiological evidence suggests that the bacterial isolates in this study could be used as natural antimicrobial agents and may be considered safe for probiotic application.