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Applied and Environmental Microbiology Jul 2022High-throughput sequencing and high-pressure liquid chromatography (HPLC) methods were used to investigate the influences of microbial dynamics on the quality and...
High-throughput sequencing and high-pressure liquid chromatography (HPLC) methods were used to investigate the influences of microbial dynamics on the quality and biogenic amine (BA) content during fish sauce fermentation. The homogeneity of total viable bacteria and lactic acid bacteria in fish sauce becomes higher as fermentation progresses. was the key genus of fish sauce fermentation. (38.43%) and (41.01%) were the dominant genera in the samples fermented for 3 months and 18 months, respectively. These three bacterial genera were significantly related to the physicochemical characteristics and characteristic flavors of the sauces. was significantly positively correlated with nitrogen oxides, the main characteristic flavor components in fish sauce. The BA content in fish sauce fermentation increased from 106.88 to 376.03 mg/kg, and the content of histamine reached 115.30 mg/kg at the end of fermentation, indicating that fish sauce has health risks. About 66.67% of isolates were able to produce a large amount of BA, suggesting that was the key genus for BA accumulation in fish sauce fermentation. Research on reducing the content of BA in fish sauce by intervening with regard to the fermentation temperature showed that a safe fish sauce product could be obtained at the fermentation temperature of about 25°C. These results help us to understand the contribution of microbial community composition to fish sauce fermentation and provide a basis for improving the quality and safety of fermented fish sauce. Traditional fermentation of fish sauce is mainly carried out by complex microbial communities from raw anchovies and processing environments. However, it is still unclear how the environmental microbiota influences the quality and the safety of fish sauce products. Therefore, this study comprehensively explained the influence of microorganisms on the quality and safety of fish sauce during the fermentation process in terms of physicochemical characters, flavors, and BA. Additionally, the accumulation of BA in fish sauce fermentation was controlled by intervening in the fermentation temperature. This finding contributes to a deeper understanding of the role of environmental microbiota during fermentation and provides data support for improving the safety of fish sauce.
Topics: Animals; Bacteria; Biogenic Amines; Enterococcaceae; Fermentation; Fish Products; Fishes; Food Microbiology
PubMed: 35695487
DOI: 10.1128/aem.00690-22 -
The Journal of Veterinary Medical... Sep 2023Melissococcus plutonius is a Gram-positive lanceolate coccus that is the causative agent of European foulbrood, an important bacterial disease of honey bee brood.... (Review)
Review
Melissococcus plutonius is a Gram-positive lanceolate coccus that is the causative agent of European foulbrood, an important bacterial disease of honey bee brood. Although this bacterium was originally described in the early 20th century, a culture method for this bacterium was not established until more than 40 years after its discovery due to its fastidious characteristics, including the requirement for high potassium and anaerobic/microaerophilic conditions. These characteristics were considered to be common to the majority of M. plutonius strains isolated worldwide, and M. plutonius was also thought to be genetically homologous or clonal for years. However, non-fastidious variants of this species (designated as atypical M. plutonius) were very recently identified in Japan. Although the morphology of these unusual strains was similar to that of traditionally well-known M. plutonius strains, atypical strains were genetically very different from most of the M. plutonius strains previously isolated and were highly virulent to individual bee larva. These atypical variants were initially considered to be unique to Japan, but were subsequently found worldwide; however, the frequency of isolation varied from country to country. The background of the discovery of atypical M. plutonius in Japan and current knowledge on atypical strains, including their biochemical and culture characteristics, virulence, detection methods, and global distribution, are described in this review. Remaining mysteries related to atypical M. plutonius and directions for future research are also discussed.
Topics: Bees; Animals; Virulence; Larva; Enterococcaceae; Bacterial Infections
PubMed: 37460304
DOI: 10.1292/jvms.23-0180 -
PloS One 2021Anti-nutritional compounds such as non-starch polysaccharides (NSP) are present in viscous cereals used in feed for poultry. Therefore, exogenous carbohydrases are...
Anti-nutritional compounds such as non-starch polysaccharides (NSP) are present in viscous cereals used in feed for poultry. Therefore, exogenous carbohydrases are commonly added to monogastric feed to degrade these NSP. Our hypothesis is that xylanase not only improves laying hen performance and digestibility, but also induces a significant shift in microbial composition within the intestinal tract and thereby might exert a prebiotic effect. In this context, a better understanding on whether and how the chicken gut microbial population can be modulated by xylanase is required. To do so, the effects of dietary supplementation of xylanase on performance, apparent total tract digestibility (ATTD) and cecal microbiome in laying hens were evaluated in the present study. A total of 96 HiSex laying hens were used in this experiment (3 diets and 16 replicates of 2 hens). Xylanase was added to the diets at concentrations of 0, 45,000 (15 g/t XygestTM HT) and 90,000 U/kg (30 g/t Xygest HT). The diets were based on wheat (~55%), soybean and sunflower meal. The lowest dosage, 45,000 U/kg, significantly increased average egg weight and improved feed efficiency compared to the control treatment (P<0.05). Egg quality parameters were significantly improved in the experiment in response to the xylanase addition. For example, during the last 28 days of the trial, birds receiving the 45,000 U/kg and the 90,000 U/kg treatments exhibited an increase in Haugh units and albumin heights (P<0.05). Compared with the control, the ATTD of organic matter and crude protein were drastically improved in the 45,000 U/kg treatment group (P<0.05). Furthermore, gross energy and the ATTD of crude fat were improved significantly for birds fed 90,000 U/kg group compared to the control. Importantly, 16S rRNA gene analysis revealed that xylanase at 45,000 U/kg dosage can exert a change in the cecal microbiome. A significant increase in beneficial bacteria (Bacilli class; Enterococcaceae and Lactobacillales orders; Merdibacter, Enterococcus and Nocardiopsis genera; Enterococcus casseliflavus species) was documented when adding 45,000 U/kg xylanase to the diet of laying hens. In conclusion, dietary supplementation of xylanase 45,000 U/kg significantly improved laying hen performance and digestibility. Furthermore, microbiome data suggest that xylanase modulates the laying hen bacterial population beneficially, thus potentially exerting a prebiotic effect.
Topics: Animal Feed; Animals; Chickens; Diet; Digestion; Enterococcus; RNA, Ribosomal, 16S
PubMed: 34543338
DOI: 10.1371/journal.pone.0257681 -
PloS One 2018Tetragenococcus halophilus is a halophilic lactic acid bacterium that exists in the traditional Japanese seasoning miso-a fermented soy paste. Considering the popularity...
Tetragenococcus halophilus is a halophilic lactic acid bacterium that exists in the traditional Japanese seasoning miso-a fermented soy paste. Considering the popularity of miso as a component of healthy diet, we attempted to evaluate the immunoregulatory functions of T. halophilus spices isolated from miso. We screened 56 strains that facilitated the upregulation of activation markers such as CD86 and CD69 on B cells and T cells in vitro. Of these, 7 strains (Nos. 1, 3, 13, 15, 19, 30, and 31) were found to preferentially induce the CD86 expression on B cells. Furthermore, DNA microarray analysis revealed that T. halophilus strain No. 1 significantly augmented the gene expressions of CD86, CD70, IL-10, INF-γ, and IL-22 in B cells. We confirmed these results at the protein level by flow cytometry. Mice feeding diet containing 1% T. halophilus No. 1 exhibited significantly greater IgA production in the serum. Furthermore, a diet containing 1% T. halophilus No. 1 augmented ovoalbumin (OVA)-specific IgG titer in mice upon OVA/alum immunization. Thus, we demonstrated that T. halophilus No. 1 is a strong immunomodulatory strain with potential as a probiotic.
Topics: Animals; B-Lymphocytes; Cytokines; Enterococcaceae; Food Microbiology; Gene Expression Regulation; Mice; Soy Foods; T-Lymphocytes
PubMed: 30586377
DOI: 10.1371/journal.pone.0208821 -
MBio Mar 2024is a member of the human gastrointestinal (GI) microbiota but can also cause invasive infections, especially in immunocompromised hosts. Enterococci display intrinsic...
UNLABELLED
is a member of the human gastrointestinal (GI) microbiota but can also cause invasive infections, especially in immunocompromised hosts. Enterococci display intrinsic resistance to many antibiotics, and most clinical isolates have acquired vancomycin resistance, leaving clinicians with a limited repertoire of effective antibiotics. As such, vancomycin-resistant (VREfm) has become an increasingly difficult to treat nosocomial pathogen that is often associated with treatment failure and recurrent infections. We followed a patient with recurrent bloodstream infections (BSIs) of increasing severity, which ultimately became unresponsive to antibiotic combination therapy over the course of 7 years. Whole-genome sequencing (WGS) showed that the patient was colonized with closely related strains for at least 2 years and that invasive isolates likely emerged from a large population in the patient's gastrointestinal (GI) tract. The addition of bacteriophage (phage) therapy to the patient's antimicrobial regimen was associated with several months of clinical improvement and reduced intestinal burden of VRE and analysis showed that antibiotic and phage combination therapy improved bacterial growth suppression compared to therapy with either alone. Eventual BSI recurrence was not associated with the development of antibiotic or phage resistance in post-treatment isolates. However, an anti-phage-neutralizing antibody response occurred that coincided with an increased relative abundance of VRE in the GI tract, both of which may have contributed to clinical failure. Taken together, these findings highlight the potential utility and limitations of phage therapy to treat antibiotic-resistant enterococcal infections.
IMPORTANCE
Phage therapy is an emerging therapeutic approach for treating bacterial infections that do not respond to traditional antibiotics. The addition of phage therapy to systemic antibiotics to treat a patient with recurrent infections that were non-responsive to antibiotics alone resulted in fewer hospitalizations and improved the patient's quality of life. Combination phage and antibiotic therapy reduced and VRE abundance in the patient's stool. Eventually, an anti-phage antibody response emerged that was able to neutralize phage activity, which may have limited clinical efficacy. This study demonstrates the potential of phages as an additional option in the antimicrobial toolbox for treating invasive enterococcal infections and highlights the need for further investigation to ensure phage therapy can be deployed for maximum clinical benefit.
Topics: Humans; Anti-Bacterial Agents; Enterococcus faecium; Bacteriophages; Quality of Life; Enterococcus; Bacteremia; Gram-Positive Bacterial Infections; Microbial Sensitivity Tests; Vancomycin-Resistant Enterococci
PubMed: 38353560
DOI: 10.1128/mbio.03396-23 -
PLoS Pathogens Jun 2023Insertion sequences (IS) are simple transposons implicated in the genome evolution of diverse pathogenic bacterial species. Enterococci have emerged as important human...
Insertion sequences (IS) are simple transposons implicated in the genome evolution of diverse pathogenic bacterial species. Enterococci have emerged as important human intestinal pathogens with newly adapted virulence potential and antibiotic resistance. These genetic features arose in tandem with large-scale genome evolution mediated by mobile elements. Pathoadaptation in enterococci is thought to be mediated in part by the IS element IS256 through gene inactivation and recombination events. However, the regulation of IS256 and the mechanisms controlling its activation are not well understood. Here, we adapt an IS256-specfic deep sequencing method to describe how chronic lytic phage infection drives widespread diversification of IS256 in E. faecalis and how antibiotic exposure is associated with IS256 diversification in E. faecium during a clinical human infection. We show through comparative genomics that IS256 is primarily found in hospital-adapted enterococcal isolates. Analyses of IS256 transposase gene levels reveal that IS256 mobility is regulated at the transcriptional level by multiple mechanisms in E. faecalis, indicating tight control of IS256 activation in the absence of selective pressure. Our findings reveal that stressors such as phages and antibiotic exposure drives rapid genome-scale transposition in the enterococci. IS256 diversification can therefore explain how selective pressures mediate evolution of the enterococcal genome, ultimately leading to the emergence of dominant nosocomial lineages that threaten human health.
Topics: Humans; Enterococcus; DNA Transposable Elements; Anti-Bacterial Agents; Drug Resistance, Microbial; Enterococcus faecalis; Enterococcus faecium
PubMed: 37267422
DOI: 10.1371/journal.ppat.1011424 -
PloS One 2022Japanese people have been consuming miso soup over generations; it is beneficial for health and longevity. In this study, Tetragenococcus halophilus No. 1 in miso was...
Japanese people have been consuming miso soup over generations; it is beneficial for health and longevity. In this study, Tetragenococcus halophilus No. 1 in miso was found to possess salient immunomodulatory functions. Recently, we also demonstrated its effect on boosting immunological robustness. Although the consumption of miso is suggested to affect health over generations, such a long-term experiment has not been conducted until now. Thus, we evaluated the effects of miso-derived T. halophilus No. 1 over generations on the immune system of mice. As the generations increase, the proportion of germinal center B cells tends to increase. Furthermore, we found that CD4+ T cells expressing CD69, an activation marker, were increased in the third generation of mice. In addition, the proportion of follicular helper T cells and regulatory T cells tended to increase. Among the subsets of CD4+ T cells in the fourth generation, effector T cells and effector memory T cells tended to increase. In contrast, central memory T cells and naive T cells decreased. Moreover, autoimmunity was suppressed by long-term administration of T. halophilus No. 1. Based on these findings, we believe that the long-term administration of T. halophilus No. 1 over generations promotes immune activation and tolerance and enhances immunological robustness.
Topics: Animals; B-Lymphocytes; Enterococcaceae; Humans; Mice; Soy Foods
PubMed: 35472068
DOI: 10.1371/journal.pone.0267473 -
The Journal of General and Applied... Jan 2018
Comparative Study
Topics: Bacterial Proteins; DNA, Bacterial; Enterococcaceae; Genes, Bacterial; Genome, Bacterial; Genomics; Metabolic Networks and Pathways; Sequence Analysis, DNA; Soy Foods; Species Specificity
PubMed: 29046500
DOI: 10.2323/jgam.2017.02.003 -
International Journal of Molecular... Nov 2023is a leading cause of nosocomial infections, particularly in immunocompromised patients. The rise of multidrug-resistant , including Vancomycin-Resistant Enterococci...
is a leading cause of nosocomial infections, particularly in immunocompromised patients. The rise of multidrug-resistant , including Vancomycin-Resistant Enterococci (VRE), is a major concern. Vaccines are promising alternatives to antibiotics, but there is currently no vaccine available against enterococci. In a previous study, we identified six protein vaccine candidates associated with extracellular membrane vesicles (MVs) produced by nosocomial . In this study, we immunized rabbits with two different VRE-derived MV preparations and characterized the resulting immune sera. Both anti-MV sera exhibited high immunoreactivity towards the homologous strain, three additional VRE strains, and eight different unrelated strains representing different sequence types (STs). Additionally, we demonstrated that the two anti-MV sera were able to mediate opsonophagocytic killing of not only the homologous strain but also three unrelated heterologous VRE strains. Altogether, our results indicate that MVs, regardless of the purification method for obtaining them, are promising vaccine candidates against multidrug-resistant and suggest that these naturally occurring MVs can be used as a multi-antigen platform to elicit protective immune responses against enterococcal infections.
Topics: Animals; Humans; Rabbits; Enterococcus faecalis; Anti-Bacterial Agents; Enterococcus faecium; Vancomycin-Resistant Enterococci; Vaccines; Gram-Positive Bacterial Infections; Microbial Sensitivity Tests
PubMed: 38003243
DOI: 10.3390/ijms242216051 -
Cells Jun 2022Ulcerative colitis (UC) is one of the major subtypes of inflammatory bowel disease with unknown etiology. Probiotics have recently been introduced as a treatment for UC....
Ulcerative colitis (UC) is one of the major subtypes of inflammatory bowel disease with unknown etiology. Probiotics have recently been introduced as a treatment for UC. () is a lactic acid-producing bacterium that survives in environments with high salt concentrations, though little is known about its immunomodulatory function as a probiotic. The purpose of this study is to determine whether exerts an anti-inflammatory effect on intestinal inflammation in mice. Colitis was induced in C57BL/6J mice by feeding 4% DSS in drinking water for 7 days. was orally administered with DSS. Anti-inflammatory functions were subsequently evaluated by flow cytometry, qRT-PCT, and ELISA. Gut microbial composition was analyzed by 16S rRNA metagenomic analysis. DSS-induced colitis mice treated with showed less weight loss and significantly suppressed colonic shortening compared to DSS-induced colitis mice. significantly reduced the frequency of the dendritic cell activation molecule CD83 in peripheral blood leukocytes and intestinal epithelial lymphocytes. Frequencies of CD8+NK1.1+ cells decreased in mice with colitis after treatment and IL-1β levels were also reduced. Alteration of gut microbiota was observed in mice with colitis after administration of . These results suggest is effective in alleviating DSS-induced colitis in mice by altering immune regulation and gut microbiome compositions.
Topics: Animals; Anti-Inflammatory Agents; Colitis; Colitis, Ulcerative; Dendritic Cells; Dextran Sulfate; Enterococcaceae; Gastrointestinal Microbiome; Inflammation; Mice; Mice, Inbred C57BL; RNA, Ribosomal, 16S
PubMed: 35741032
DOI: 10.3390/cells11121903