Anaerobic Bacteria Research Articles

Characterization of Bacteroides fragilis from the vagina of a giant panda (Ailuropoda melanoleuca) with vaginitis

BackgroundBacteroides fragilis is a prevalent anaerobic bacterium typically resides in the human vagina. It is known to potentially induce infections under specific conditions. Interestingly, there have been no previous reports of B. fragilis being isolated from the vagina of giant pandas.Case presentationA novel strain of anaerobic bacteria was isolated from the vaginal tract of a giant panda exhibiting symptoms of vaginitis. This strain, designated as GPBF01, was identified as Bacteroides fragilis, a species commonly found in the vaginal microbiome of humans and other animals. After purifying of the single colony, a series of evaluations were conducted including morphological examination, physiological and biochemical identification, antibiotic resistance analysis, resistance genes detection, 16S rRNA sequence, and phylogenetic tree sequence analysis to investigate its biological characteristics. The findings indicated the presence of a predominant anaerobic bacterium, which was identified as B. fragilis and temporarily named GPBF01 with unique biological traits not previously.ConclusionsThis study is the first to report B. fragilis in the vaginal tract of giant pandas. The analysis of antibiotic resistance patterns among anaerobic bacteria, as conducted in this research, is critical for informing the selection of appropriate antimicrobial agents in the clinical treatment of vaginitis in this species. The findings of this report substantially enhance the scientific basis needed to understand the etiology and refine therapeutic approaches for vaginitis in giant pandas.

Low Prevalence of Anaerobic Bacteria in Pediatric Septic Arthritis Makes Obtaining Anaerobic Cultures of Questionable Value.

Pediatric acute septic arthritis necessitates urgent identification and treatment to avoid irreversible joint damage if not recognized and treated in a timely manner. Many centers routinely obtain both aerobic and anaerobic cultures for the purpose of pathogen identification; however, the yield of anaerobic culture results has been called into question. The goal of this study was to determine the positivity rate of anaerobic cultures collected intraoperatively in pediatric patients with clinically diagnosed septic arthritis. Patients with a clinical diagnosis of septic arthritis were extracted from a search of musculoskeletal infections at a large tertiary care pediatric hospital from 2007 to 2021. Cultures obtained from the operating room or through arthrocentesis were examined. We identified 470 cases of pediatric septic arthritis of which only 3 cultures were positive (0.6%) for anaerobic organisms. All cases involved a single isolate. The anaerobic bacteria that were detected included 1 facultative anaerobe, 1 strict anaerobe, and 1 relatively aerotolerant anaerobe. Four aerobic organisms grew on the anaerobic cultures. Three of the false positives also grew on aerobic culture media, whereas 1 aerobic specimen grew explicitly on anaerobic media. Neither the facultative anaerobe nor the aerotolerant anaerobe grew on aerobic culture media. Over a 14-year period, only 0.6% (3 cases) of septic arthritis cases yielded positive anaerobic cultures that were not able to be cultured on aerobic media. As such, an anaerobic culture was more likely to culture a bacterium that would have also been cultured on aerobic media. In addition, a true positive anaerobic culture that would not have been diagnosed on aerobic cultures only occurs about once every 5 years at our institution. If one were to decide against obtaining anaerobic cultures, they would only miss 3 infections out of almost 500 (0.6%), and antibiotics would only have changed 0.6% of the time. These results suggest that routinely obtaining anaerobic cultures may be of limited value in pediatric septic arthritis. The false-positive rate of anaerobic labs exceeds that of true-positive cases. These results provide actionable opportunity to help guide clinician decision-making in a more cost-effective and efficient management of pediatric septic arthritis. IV.

Development of a clinical metagenomics workflow for the diagnosis of wound infections

BackgroundWound infections are a common complication of injuries negatively impacting the patient’s recovery, causing tissue damage, delaying wound healing, and possibly leading to the spread of the infection beyond the wound site. The current gold-standard diagnostic methods based on microbiological testing are not optimal for use in austere medical treatment facilities due to the need for large equipment and the turnaround time. Clinical metagenomics (CMg) has the potential to provide an alternative to current diagnostic tests enabling rapid, untargeted identification of the causative pathogen and the provision of additional clinically relevant information using equipment with a reduced logistical and operative burden.MethodsThis study presents the development and demonstration of a CMg workflow for wound swab samples. This workflow was applied to samples prospectively collected from patients with a suspected wound infection and the results were compared to routine microbiology and real-time quantitative polymerase chain reaction (qPCR).ResultsWound swab samples were prepared for nanopore-based DNA sequencing in approximately 4 h and achieved sensitivity and specificity values of 83.82% and 66.64% respectively, when compared to routine microbiology testing and species-specific qPCR. CMg also enabled the provision of additional information including the identification of fungal species, anaerobic bacteria, antimicrobial resistance (AMR) genes and microbial species diversity.ConclusionsThis study demonstrates that CMg has the potential to provide an alternative diagnostic method for wound infections suitable for use in austere medical treatment facilities. Future optimisation should focus on increased method automation and an improved understanding of the interpretation of CMg outputs, including robust reporting thresholds to confirm the presence of pathogen species and AMR gene identifications.

Oral health promotion of flavonoids from Scutellaria baicalensis

Looking for materials from Scutellaria baicalensis to improve oral inflammation and eliminate bad breath led to one new compound, 5,7,2′,5′-tetrahydroxy-6′-methoxyflavone (1) and 32 known ones. Among of them, 3 flavones (11, 17, 18), 2 dihydroflavones (23, 25), 2 flavone glucosides (30, 32), and a chalcone (26) could inhibit oral anaerobic bacteria Fusobacterium nucleatum, Streptococcus mutans, and Porphyromonas gingivalis. Compounds 3, 14, 18 could inhibit oral bacterial Staphylococcus aureus. Compounds 5, 8, 13 and 21 exhibited strong inhibitory NO production. Additionally, 14 and 26 showed good COX-1/2 inhibitory effects. These results indicated S. baicalensis has potential oral health benefits.

Integrated Rice-Snail-Crayfish Farming System Shapes Soil Microbial Community by Enhancing pH and Microbial Biomass in South Subtropical China

Within the framework of sustainable agriculture, the integrated rice-snail-crayfish farming system has been recognized as a highly efficient agroecological approach that enhances crop production while minimizing the application of chemical fertilizers and pesticides. Nonetheless, the mechanisms by which this system influences soil microbial community composition to achieve these benefits remain unknown. In this study, we focused on traditional rice farming (TR), the integrated rice-snail-crayfish (R-S-C) farming system, and mono-rice farming (CK), and systematically examined the impacts of these farming systems on soil chemical properties, microbial biomass, enzyme activity, and microbial community composition. Our results showed that the R-S-C significantly increased soil pH, microbial biomass carbon (MBC), and the MBC/microbial biomass phosphorus (MBP) ratio compared to TR, as well as the peroxidase activity. Moreover, the R-S-C significantly increased soil total phospholipid fatty acid (PLFA), bacterial PLFAs, Gram-negative bacterial (GN) PLFAs, anaerobic bacteria PLFAs, arbuscular mycorrhizal fungi (AMF) abundances, and the bacteria/fungi ratio compared to the other two systems. However, the soil microbial α-diversity indices, including Shannon–Wiener index (H), Simpson index (D), and Pielou evenness index (J), were significantly lower in the R-S-C system than in the other two systems. Further exploration suggested that soil pH, microbial biomass nitrogen (MBN), the MBN/total nitrogen (TN) ratio, and the MBC/MBP ratio were critical factors governing microbial community composition under the three farming practices. Notably, soil pH alone accounted for 64.5% of the observed variation in microbial community composition. Path analysis using partial least squares structural equation modeling further revealed the pathways by which the R-S-C system enhanced total PLFAs, AMF, and gram-positive bacteria by regulating the soil pH and MBN/TN ratio. This study provides insights into the regulatory mechanisms driving soil microbial communities in the R-S-C system and offers a theoretical foundation for developing sustainable agricultural management practices.

Gut Microbiota Comparison in Rectal Swabs Versus Stool Samples in Cats with Kidney Stones

To investigate the role of the intestinal bacterial microbiota in the pathogenesis of calcium oxalate nephrolithiasis in cats, a condition characterized by the formation of kidney stones, it is desirable to identify a sample collection method that accurately reflects the microbiota’s composition. The objective of this study was to evaluate the impact of fecal sample collection methods on the intestinal microbiota composition in two cat populations: healthy cats and kidney stone-diseased cats. The study included eighteen cats from the same colony, comprising nine healthy cats and nine cats with spontaneously occurring presumed calcium oxalate kidney stones. Three fecal collection methods were compared: rectal swabs, the collection of fresh stool, and the collection of stool exposed to ambient air for 24 h. The bacterial microbiota was analyzed through the high-resolution sequencing of the V3–V4 region of the 16S rRNA gene. For all cats, within the same individual, a one-way PERMANOVA analysis showed a significant difference between the rectal swabs and fresh stool (p = 0.0003), as well as between the rectal swabs and stool exposed to ambient air for 24 h (p = 0.0003), but no significant difference was identified between the fresh stool and non-fresh stool (p = 0.0651). When comparing the two populations of cats, this study provides seemingly conflicting results. (1) A principal component analysis (PCA) comparison revealed a significant difference in the bacterial composition between the healthy cats and the cats with kidney stones only when the sample was a fresh fecal sample (p = 0.0037). This finding suggests that the intestinal bacteria involved in the pathogenesis of kidney stones in cats are luminal and strictly anaerobic bacteria. Consequently, exposure to ambient air results in a loss of information, preventing the identification of dysbiosis. For clinical studies, non-fresh stool samples provided by owners does not appear suitable for studying the gut microbiota of cats with kidney stones; fresh stool should be favored. (2) Interestingly, the rectal swabs alone highlighted significant differences in the proportion of major phyla between the two populations. These findings highlight the critical importance of carefully selecting fecal collection methods when studying feline gut microbiota. Combining rectal swabs and fresh stool sampling provides complementary insights, offering the most accurate understanding of the gut microbiota composition in the context of feline kidney stone pathogenesis.

Identification of nanaomycin A and its analogs by a newly established screening method for functional inhibitors of the type IX secretion system in Porphyromonas gingivalis.

Porphyromonas gingivalis, a Gram-negative anaerobic bacterium, is a key pathogen in chronic periodontitis. P. gingivalis has a type IX secretion system (T9SS) that secretes highly hydrolytic proteinases called gingipains for obtaining peptides as an energy source. Although most T9SS-related proteins have been identified, no specific inhibitor of T9SS has been reported. To screen T9SS inhibitors, we focused on and characterized a minimal liquid medium called mC medium that contains milk casein as the sole protein source. We found that P. gingivalis wild-type strain ATCC 33277 caused cloudiness of mC medium without growth. In mC medium, an alkylating agent, iodoacetamide (IAM) that is an inhibitor of gingipains, and a protonophore, carbonyl cyanide 3-chlorophenylhydrazone (CCCP) that dissipates the proton motive force required for T9SS-mediated secretion, clearly inhibited the increase in turbidity. Moreover, neither the gingipain-null mutant nor the T9SS-deficient mutant caused mC medium cloudiness, suggesting that mC medium cloudiness is dependent on gingipain activity and T9SS. These results indicated that mC medium can be used to assess P. gingivalis gingipain activity and its functional T9SS. Using an assay system with mC medium, we discovered that OM-173αA and OM-173βA in the Ōmura Natural Compound Library and nanaomycin A were probable T9SS inhibitors. The compounds need to be further investigated as tools for analyzing T9SS and as potential therapeutic agents for periodontal disease.

Flowable Oxygen-Release Hydrogel Inhibits Bacteria and Treats Periodontitis.

Periodontitis, the chronic inflammation of the periodontal tissues caused by bacteria in plaque, is the leading cause of tooth loss in adults in the world. Currently, periodontitis is effectively treated with mechanical cleaning and the use of antibiotics. However, these treatments only temporarily remove plaque, which can rapidly proliferate and multiply in periodontal pockets over time. Although antibiotics have positive antimicrobial effects, their long-term use increases the risk of the emergence of drug-resistant strains. The emergence of resistant strains reduces the effectiveness of periodontitis treatment and makes the disease more difficult to control. Herein, this paper reports the development of an injectable self-oxygenating composite hydrogel for periodontal therapy, which was produced by loading CaO2 nanoparticles and ascorbic acid into an injectable alginate hydrogel. CaO2 can improve the periodontal pocket microenvironment by reacting with water to generate oxygen, calcium ions can be used as a bone regeneration material, and ascorbic acid protects cells. The authors further showed that the composite hydrogel inhibited growth and colonization of anaerobic bacteria, reduced the degree of inflammation, and promoted alveolar bone regeneration. In conclusion, these findings suggest that the composite hydrogel can be used as a biocompatible, convenient, and effective method for periodontitis treatment.

Effects of Minocycline on Early Wound Healing after Implant Placement: An InVitro and Randomized Clinical Study.

To determine the invitro effects of minocycline on human gingival fibroblasts (HGFs), its clinical impact on early wound healing after implant placement, and its potential mechanism of action. First, we evaluated the invitro proliferation, migration, and collagen production of HGFs treated with different concentrations of minocycline, as well as the underlying mechanism. Subsequently, we conducted a clinical trial and randomly assigned 40 partially edentulous patients to either the test (minocycline hydrochloride treatment) or control (blank control) group immediately after implant surgery. The early wound healing score (EHS), pain index, gingival index (GI), modified sulcus bleeding index (mSBI), and peri-implant crevicular fluid samples were assessed or collected 3 and/or 7 days after surgery. In vitro, 1 μg/mL minocycline promoted the proliferation, migration, and collagen production of HGFs. Minocycline inhibited collagen degradation by downregulating the expression of matrix metalloproteinase-2 (MMP-2) and MMP-14 and upregulating tissue inhibitors of metalloproteinases-2. However, higher concentrations of minocycline, 10 and 100 μg/mL, exhibited adverse effects. In the randomised clinical trial, the test group showed significantly better clinical outcomes compared to the control group, with higher EHS and lower GI, mSBI, concentrations of IL-1β, IL-10, and TNF-α, and relative abundance of Streptococcus and gram-negative anaerobic bacteria. Small doses of minocycline (1 μg/mL) promoted the proliferation and migration of HGFs and inhibited collagen degradation invitro. Locally delivered minocycline after implant surgery improves clinical outcomes by promoting early wound healing, relieving the inflammatory response, and decreasing early colonisation of gram-negative anaerobic bacteria. This clinical trial was registered in the Chinese Clinical Trial Registry (registration number: ChiCTR2100044680).

Chemical and Microbiological Characterization of Freeze-Dried Superworm (Zophobas morio F.) Larvae Pretreated by Blanching and Ultrasound Treatment.

Edible insects may solve the current problem of the greater demand for food for the world's growing human population. This work aimed to examine the impact of blanching (BL) and ultrasound (US) at 20 and 50 °C as a pretreatment method on the chemical composition, mineral composition, FTIR spectra, presence of allergens and microorganisms, and properties of the isolated oil of freeze-dried superworm larvae. The US treatment resulted in significantly lower protein content (31.65-33.34 g/100 g d.m.) compared to untreated (36.38 g/100 g d.m.) and BL (37.72 g/100 g d.m.) samples. The study demonstrated that the US-treated insects exhibited a lower content of crustacean and mollusk allergens than the BL insects, and the lowest content of tested allergens was found in the US_50°C superworm larvae. Furthermore, oil isolated from US_50°C insects exhibited the lowest SFA and the highest PUFA content and the best prospective nutritional properties expressed through theoretical health indices. The presence of Enterobacteriaceae and anaerobic spore-forming bacteria was not detected in the tested insects, proving suitable microbiological quality. It appears that using US treatment is a promising alternative to traditional blanching of insects before drying.

Microbial exposure during recycling of domestic waste: a cross-sectional study of composition and associations with inflammatory markers

ObjectivesThis study aims to investigate (1) the microbial community composition by work characteristics and (2) the association between microbial genera level and inflammatory markers among recycling workers.MethodsIn this cross-sectional study,...

Bacteriemias por anaerobios estrictos

Introduction. Anaerobic bacteremia represents 0.5-12% of all bacteremias and its mortality is high, ranging from 25-44%. The aim was to know our data to compare them with existing data and demonstrate the importance of actively searching for these microorganisms in blood culture samples. Material and methods. A retrospective descriptive study in which the medical records of patients with significant episodes of anaerobic bacteremia were reviewed over a period of 8 years (2014-2022). Results. A total of 59,898 blood cultures were processed, of which 10,451 were positive (17%). An anaerobic microorganism was identified in 209 patients. Anaerobic bacteremia accounted for 2.11% of the total number of positive blood cultures. The mean age was 63.55 years (17-96), 66% of whom were men. The origin was community in 63.64%, of nosocomial origin in 15.31% and associated with health care in 17.70%. The focus of infection was the abdominal (39.23%), followed by the respiratory (13.88%) and skin and soft tissues (13.39%). The most frequent comorbidities were: arterial hypertension (49.76%), dyslipidemia (29.67%), neoplasia (26.32%) and diabetes (26.32%). The main species isolated were the group Bacteroides spp. (44.50%) (n=93) highlighting Bacteroides group fragilis (n=65), followed by Clostridium spp. (20%) (n=42) highlighting Clostridium perfringens (n=30). The clinical evolution was good in 67.46%. The mean length of stay was 27.8 days and was associated with 20% mortality. Conclusions. Bacteremias due to anaerobes represented 2.11% of the total number of true bacteremias, so we consider the active search for these microorganisms to be appropriate.

Disentangling the microbial genomic traits associated with aromatic hydrocarbon degradation in a jet fuel-contaminated aquifer.

Spills of petroleum or its derivatives in the environment lead to an enrichment of microorganisms able to degrade such compounds. The interactions taking place in such microbial communities are complex and poorly understood, since they depend on multiple factors, including diversity and metabolic potential of the microorganisms and a broad range of fluctuating environmental conditions. In our previous study, a complete characterization, based on high-throughput sequencing, was performed in a jet-fuel plume using soil samples and in in-situ microcosms amended with hydrocarbons and exposed for 120days. Herein, we propose a metabolic model to describe the monoaromatic hydrocarbon degradation process that takes place in such jet-fuel-contaminated sites, by combining genome-centered analysis, functional predictions, and flux balance analysis (FBA). In total, twenty high/medium quality MAGs were recovered; three of them assigned to anaerobic bacteria (Thermincolales, Geobacter and Pelotomaculaceace) and one affiliated to the aerobic bacterium Acinetobacter radioresistens, potentially the main players of hydrocarbon degradation in jet-fuel plumes. Taxonomic assignment of the genes indicated that a putative new species of Geobacteria has the potential for anaerobic degradation pathway, while the Pelotomaculaceae and Thermincolales members probably act via syntrophy oxidizing acetate and hydrogen (fermentation products of oil degradation) via sulfate and/or nitrate reduction.

Functional Outcome Prediction of Acute Ischemic Stroke Based on the Oral and Gut Microbiota.

Although several studies have identified a distinct gut microbiota in individuals with acute ischemic stroke (AIS), there is a limited amount of research that has simultaneously investigated alterations in the oral and intestinal microbiota in AIS patients and their correlation with clinical prognosis. This was a prospective and observational single-center cohort study in which we included 160 AIS patients who were admitted within 24h after a stroke event. We collected oral and rectal swab samples for analysis using 16S rRNA high-throughput sequencing. Our study revealed that patients with unfavorable outcomes after AIS showed early disruptions in their oral and intestinal microbiota. Rectal swabs showed increased levels of facultatively anaerobic bacteria in patients with a poor prognosis, while the oral cavity exhibited higher levels of anaerobic and opportunistic pathogenic bacteria. By employing machine learning analysis, we found that the microbiota composition at both rectal and oral sites could predict early and long-term outcomes. Moreover, patients with a poor prognosis displayed increased oral bacterial colonization in the rectal microbiota and altered interactions between the oral and gut microbiota. This study reveals distinct rectal and oral bacteria that could predict unfavorable outcomes for AIS patients. Monitoring the microbiota of various body sites during the early stages after admission may hold prognostic value and inform personalized treatment strategies. The presence of oral bacteria colonizing the intestines during the acute phase of stroke could serve as an early indication of poor outcomes for AIS patients.

Dressing Material With Halochromic Dye as an Information Source in Wound Healing Monitoring

Background: The percentage of clean-wound infection remains fairly high so far: 2% to 5%. Therefore, monitoring wound healing is a critical task in modern surgery.Objective: To develop and test a dressing material with halochromic dye in order to determine the suppuration of a clean wound of the skin and soft tissues.Material and methods: The experiment was conducted on 30 Wistar rats: clean wounds were formed and then covered with a dressing soaked in halochromic dye. During the experiment, we measured the pH of the wounds and wound area and determined the qualitative and quantitative composition of the wound microflora. Statistical analysis was conducted using the Wilcoxon test; the level of significance was taken at 0.05.Results: We found that the initial wound area was 253 (248; 257) mm2 and the surface pH, 5.80 (5.55; 5.90). Clean wounds covered with a dressing material were not treated with medication. It led to their infection and a change in the color of the dressing material on average on day 4 (4; 5) of the experiment. After removal of the dressing material, we noted that the pH of the wounds was 7.79 (7.68; 7.88) and the wound area, 238 (234.3; 242.5) mm2; the differences compared with the data on day 1 were statistically significant. When analyzing the degree of wound contamination after removal of the dressing material, we found that the wound contained aerobic and anaerobic microorganisms and microscopic fungi, the level of which statistically significantly exceeded the maximum permissible level, confirming development of the wound infection.Conclusions: The use of a dressing material with halochromic dye, which changes its color in response to the pH of the wound, facilitates timely detection of the development of the wound infection.

Niche-Aware Metagenomic Screening for Enzyme Methioninase Illuminates Its Contribution to Metabolic Syntrophy

The single-step methioninase-mediated degradation of methionine (as a sulfur containing amino acid) is a reaction at the interface of carbon, nitrogen, sulfur, and methane metabolism in microbes. This enzyme also has therapeutic application due to its role in starving auxotrophic cancer cells. Applying our refined in silico screening pipeline on 33,469 publicly available genome assemblies and 1878 metagenome assembled genomes/single-cell amplified genomes from brackish waters of the Caspian Sea and the Fennoscandian Shield deep groundwater resulted in recovering 1845 methioninases. The majority of recovered methioninases belong to representatives of phyla Proteobacteria (50%), Firmicutes (29%), and Firmicutes_A (13%). Prevalence of methioninase among anaerobic microbes and in the anoxic deep groundwater together with the relevance of its products for energy conservation in anaerobic metabolism highlights such environments as desirable targets for screening novel methioninases and resolving its contribution to microbial metabolism and interactions. Among archaea, majority of detected methioninases are from representatives of Methanosarcina that are able to use methanethiol, the sulfur containing product from methionine degradation, as a precursor for methanogenesis. Branching just outside these archaeal methioninases in the phylogenetic tree, we recovered three methioninases belonging to representatives of Patescibacteria reconstructed from deep groundwater metagenomes. We hypothesize that methioninase in Patescibacteria could contribute to their syntrophic interactions where their methanogenic partners/hosts benefit from the produced 2-oxobutyrate and methanethiol. Our results underscore the significance of accounting for specific ecological niche in screening for enzyme variates with desired characteristics. Finally, complementing of our findings with experimental validation of methioninase activity confirms the potential of our in silico screening in clarifying the peculiar ecological role of methioninase in anoxic environments.

Microbiota of complete removable dentures

Purpose: to study the quantitative and qualitative composition of microflora on the surface of complete removable dentures after 1 and 4 years of use. Materials and methods: 40 patients were diagnosed with complete edentulism (K08.1) using complete removable acrylic dentures for no more than 4 years were examined. The composition of the microflora was determined by mass spectrometry method. Statistical processing of the results of the study was carried out using the computer package Statistica13. To assess the differences between the groups, parametric t-criteria with Bonferroni correction were used for multiple comparisons, the critical level of statistical significance of p was 0.05. Results: it was found that in 4 years the number of yeast and fungi increased by 91%, n=20 (100%); the number of actinobacteria increased by 61%, n=20 (100%); the number of gram-negative bacteria increased by 500% n=20 (100%); the number of anaerobic microorganisms increased by 50% n=20 (100%); the number of cocci and bacilli increased by 190% n=20 (100%). Conclusion: after conducting the research, we found that after 4 years of using removable dentures n=20 (100%), the number of cocci and bacilli increased from 56±5 (105 cells/gram) (p=0.03) to 107±8 (105 cells/gram) (p=0.04). The number of anaerobes increased n=20 (100%) from 68±6 (105 cells/gram) (p=0.0002) to 102±9 (105 cells/gram) (p=0.0002). The number of actinobacteria n=20 (100%) increased from 30±3 (105 cells/gram) to 143±12 (105 cells/gram) (p=0.003). The number of gram-negative bacteria n=20 (100%) increased from 4±1 (105 cells/gram) (p=0.0005) to 24±2 (105 cells/gram) (p=0.0006). The number of fungi and yeast n=20 (100%) increased from 977±90 (105 cells/gram) (p=0.0003) to 1587±136 (105 cells/gram) (p=0.003).

Characteristics and in vitro properties of potential probiotic strain Fructobacillus tropaeoli KKP 3032 isolated from orange juice.

Fructobacillus, a Gram-positive, non-spore-forming, facultative anaerobic bacterium, belongs to the fructophilic lactic acid bacteria (FLAB) group. The group's name originates from fructose, the favored carbon source for its members. Fructobacillus spp. are noteworthy for their distinctive traits, captivating the interest of scientists. However, there have been relatively few publications regarding the isolation and potential utilization of these microorganisms in the industry. In recent years, F. tropaeoli has garnered interest for its promising role in the food and pharmaceutical sectors, although the availability of isolates is rather limited. A more comprehensive understanding of Fructobacillus is imperative to evaluate their functionality in the industry, given their unique and exceptional properties. Our in vitro study on Fructobacillus tropaeoli KKP 3032 confirmed its fructophilic nature and high osmotolerance. This strain thrives in a 30% sugar concentration, shows resistance to low pH and bile salts, and exhibits robust autoaggregation. Additionally, it displays significant antimicrobial activity against foodborne pathogens. Evaluating its probiotic potential, it aligns with EFSA recommendations in antibiotic resistance, except for kanamycin, to which it is resistant. Further research is necessary, but preliminary analyses confirm the high probiotic potential of F. tropaeoli KKP 3032 and its ability to thrive in the presence of high concentrations of fructose. The results indicate that the isolate F. tropaeoli KKP 3032 could potentially be used in the future as a fructophilic probiotic, protective culture, and/or active ingredient in fructose-rich food.

CD47 and thrombospondin-1 contribute to immune evasion by Porphyromonas gingivalis

Porphyromonas gingivalis is a gram-negative anaerobic bacterium linked to periodontal disease. Remarkably, P. gingivalis thrives in an inflamed environment rich in activated neutrophils. Toll-like receptor 2 (TLR2) recognition is required for P. gingivalis to evade innate immune killing; however, the mechanisms through which P. gingivalis uncouples host inflammation from bactericidal activity are only partially known. Since integrin activation and alternative signaling are implicated in P. gingivalis TLR2-mediated immune escape, we explored the role of CD47, a widely expressed integrin-associated protein known to suppress phagocytosis and implicated as an interacting partner with other innate immune receptors. We found that CD47 associates with TLR2, and blocking CD47 leads to decreased intracellular P. gingivalis survival in macrophages in a manner dependent on the bacterial major fimbria. In vivo, CD47 knock-out mice cleared P. gingivalis more efficiently than wild-type mice. Next, we found increased expression and secretion of the CD47 ligand thrombospondin-1 (TSP-1) following P. gingivalis infection. Secreted TSP-1 broadly protected P. gingivalis and other periodontitis-associated bacterial species from neutrophil bactericidal activity. Therefore, CD47-TLR2 cosignaling in response to P. gingivalis induces TSP-1 that in turn suppresses neutrophil activity, an effect that can explain how species such as P. gingivalis survive in an inflamed environment and cause dysbiosis.

Bacteriology of Aspiration Pneumonia: The Lung Microbiome and the Changing Microbial Etiology.

Aspiration pneumonia refers to the process of alveolar inflammation induced by the inhalation of oropharyngeal secretions into the lower respiratory tract. Predisposing factors comprise swallowing dysfunction, impaired cough reflex, and degenerative neurological diseases. Accumulating evidence projects a fading contribution of anaerobic bacteria in aspiration pneumonia at the expense of Gram-negative bacilli, with Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa, becoming the predominant organisms recovered from respiratory specimens. Aspiration of oropharyngeal secretions colonized with respiratory pathogens induces a profound disequilibrium of the lung microbiota resulting in a state of dysbiosis. Understanding this complex temporal variability between microbiome-host associations was only made possible with the introduction of metagenomic sequencing. In this narrative review, we summarize existing knowledge and elaborate on the evolving microbiology of aspiration pneumonia including the link between oral microbiome and pulmonary aspiration. We also highlight the progress and challenges in instituting microbiome-targeted strategies for preventing and treating the sequelae of aspiration pneumonia.