Bacteroides vulgatus SNUG 40005 Restores Akkermansia Depletion by Metabolite Modulation.

BACKGROUND & AIMS: Weight loss and exercise intervention have been reported to increase the interaction between Bacteroides spp and Akkermansiamuciniphila (Am), although the underlying mechanisms and consequences of the interaction remain unknown. METHODS: Using a healthy Korean twin cohort (n = 582), we analyzed taxonomic associations with host body mass index. B vulgatus strains were isolated from mice and human subjects to investigate the strain-specific effect of B vulgatus SNUG 40005 (Bvul) on obesity. The mechanisms underlying Am enrichment by Bvul administration were investigated by multiple experiments: (1) in vitro cross-feeding experiments, (2) construction of Bvul mutants with the N-acetylglucosaminidase gene knocked out, and (3) in vivo validation cohorts with different metabolites. Finally, metabolite profiling in mouse and human fecal samples was performed. RESULTS: An interaction between Bvul and Am was observed in lean subjects but was disrupted in obese subjects. The administration of Bvul to mice fed a high-fat diet decreased body weight, insulin resistance, and gut permeability. In particular, Bvul restored the abundance of Am, which decreased significantly after a long-term high-fat diet. A cross-feeding analysis of Am with cecal contents or Bvul revealed that Am enrichment was attributed to metabolites produced during mucus degradation by Bvul. The metabolome profile of mouse fecal samples identified N-acetylglucosamine as contributing to Am enrichment, which was confirmed by in vitro and in vivo experiments. Metabolite network analysis of the twin cohort found that lysine serves as a bridge between N-acetylglucosamine, Bvul, and Am. CONCLUSIONS: Strain-specific microbe-microbe interactions modulate the mucosal environment via metabolites produced during mucin degradation in the gut.

Lactobacillus acidophilus KBL409 protects against kidney injury via improving mitochondrial function with chronic kidney disease.

PURPOSE: Recent advances have led to greater recognition of the role of mitochondrial dysfunction in the pathogenesis of chronic kidney disease (CKD). There has been evidence that CKD is also associated with dysbiosis. Here, we aimed to evaluate whether probiotic supplements can have protective effects against kidney injury via improving mitochondrial function. METHODS: An animal model of CKD was induced by feeding C57BL/6 mice a diet containing 0.2% adenine. KBL409, a strain of Lactobacillus acidophilus, was administered via oral gavage at a dose of 1 × 109 CFU daily. To clarify the underlying mechanisms by which probiotics exert protective effects on mitochondria in CKD, primary mouse tubular epithelial cells stimulated with TGF-ß and p-cresyl sulfate were administered with butyrate. RESULTS: In CKD mice, PGC-1α and AMPK, key mitochondrial energy metabolism regulators, were down-regulated. In addition, mitochondrial dynamics shifted toward fission, the number of fragmented cristae increased, and mitochondrial mass decreased. These alterations were restored by KBL409 administration. KBL409 supplementation also improved defects in fatty acid oxidation and glycolysis and restored the suppressed enzyme levels involved in TCA cycle. Accordingly, there was a concomitant improvement in mitochondrial respiration and ATP production assessed by mitochondrial function assay. These favorable effects of KBL409 on mitochondria ultimately decreased kidney fibrosis in CKD mice. In vitro analyses with butyrate recapitulated the findings of animal study. CONCLUSIONS: This study demonstrates that administration of the probiotic Lactobacillus acidophilus KBL409 protects against kidney injury via improving mitochondrial function.

Nerve injury-induced gut dysbiosis contributes to spinal cord TNF-α expression and nociceptive sensitization.

The impact of the gut microbiota on glial cell growth and maturation via the gut-brain axis is highlighted herein. Considering that glial activation is crucial for onset and maintenance of neuropathic pain, we assessed the putative involvement of gut microbiota in the pathogenesis of neuropathic pain. Depletion of mouse gut microbiota with chronic antibiotics cocktail treatment prevented nerve injury-induced mechanical allodynia and thermal hyperalgesia both in male and female mice. Furthermore, post-injury treatment with antibiotics cocktail relieved ongoing pain in neuropathic pain-established mice. Upon recolonization of the gut microbiota after cessation of antibiotics, nerve injury-induced mechanical allodynia relapsed. Depletion of gut microbiota accompanied a decrease in nerve injury-induced TNF-α expression in the spinal cord. Notably, nerve injury changed the diversity and composition of the gut microbiome, which was measured by 16 s rRNA sequencing. We then tested if probiotic administration ameliorating dysbiosis affected the development of neuropathic pain after nerve injury. Probiotic treatment for three weeks prior to nerve injury inhibited nerve injury-induced TNF-α expression in the spinal cord and pain sensitization. Our data reveal an unexpected link between the gut microbiota and development and maintenance of nerve injury-induced neuropathic pain, and we propose a novel strategy to relieve neuropathic pain through the gut-brain axis.

Clostridium fessum sp. nov., isolated from human faeces.

An obligately anaerobic, Gram-stain-positive and spore-forming strain, SNUG30386T was isolated from a faecal sample of a healthy Korean subject. The strain formed a round ivory-coloured colony and cells were chained rods with tapered ends, approximately 2.0-2.5×0.6-0.8 µm in size. The taxonomic analysis indicated that strain SNUG30386T was within the family Lachnospiraceae. According to the 16S rRNA gene sequence similarity, the closest species to strain SNUG30386T was Clostridium symbiosum (95.6 %), followed by Enterocloster asparagiformis (94.8 %), Enterocloster clostridioformis (94.8 %) and Enterocloster lavalensis (94.6 %). The evolutionary tree based on 16S rRNA gene sequences demonstrated that strain SNUG30386T had split apart at a unique branch point far from other close relatives. Its DNA G+C content was 48.3 mol% calculated from the whole genome sequence. The major cellular fatty acids were C16 : 0 and C14 : 0. Compared to those of the closely related species, strain SNUG30386T showed distinct biochemical activities such as being unable to utilize most of carbon sources except d-glucose and l-arabinose. As a result, based on its unique phylogenetic clade and taxonomic characteristics, we conclude that strain SNUG30386T represents a novel species within the genus Clostridium, for which the name Clostridium fessum sp. nov. is proposed. The type strain of the novel species is SNUG30386T (=KCTC 15633T= JCM 32258T).

Faecalibacillus intestinalis gen. nov., sp. nov. and Faecalibacillus faecis sp. nov., isolated from human faeces.

Two long-rod-shaped, Gram-stain-positive, obligately anaerobic and non-spore-forming strains, SNUG30099T and SNUG30370T, were isolated from faecal samples of healthy Korean subjects. The strains formed circular ivory-coloured colonies on Brain-heart infusion medium supplemented with 0.5% Difco yeast extract (YBHI) agar and cells were approximately 3.5-4.5×0.3-0.4 µm in size. Taxonomic analyses based on 16S rRNA gene sequences distinguished the strains from other species within the family Erysipelotrichaceae. The closest relative of strains SNUG30099T and SNUG30370T was Longibaculum muris (92.9 % and 93.6 % similarity, respectively), followed by Clostridium saccharogumia (92.3 % and 92.2 %). Phylogenetic inference also divided the strains into a unique branch that differed from other related strains that belong to the family Erysipelotrichaceae. DNA G+C contents based on the whole genome sequences of strains SNUG30099T and SNUG30370T were 29.2 and 30.2 mol%, respectively. Both novel strains possessed meso-diaminopimelic acid as the peptidoglycan, and phosphatidylethanolamine was observed as one of the major polar lipids. The major cellular fatty acid composition was different from those of other related taxa. In addition, the profile of biochemical activities advocated that the strains have distinct characteristics in comparison to other strains. Taken together, a novel genus, named Faecalibacillus gen. nov., is proposed, which includes the type species Faecalibacillus intestinalis sp. nov. for strain SNUG30099T and Faecalibacillus faecis sp. nov. for strain SNUG30370T. The type strains of these novel species are SNUG30099T (=KCTC 15631T=JCM 32256T) and SNUG30370T (=KCTC 15632T=JCM 32257T).

The effect of heritability and host genetics on the gut microbiota and metabolic syndrome.

OBJECTIVE: Metabolic syndrome (MetS) arises from complex interactions between host genetic and environmental factors. Although it is now widely accepted that the gut microbiota plays a crucial role in host metabolism, current knowledge on the effect of host genetics on specific gut microbes related to MetS status remains limited. Here, we investigated the links among host genetic factors, gut microbiota and MetS in humans. DESIGN: We characterised the gut microbial community composition of 655 monozygotic (n=306) and dizygotic (n=74) twins and their families (n=275), of which approximately 18% (121 individuals) had MetS. We evaluated the association of MetS status with the gut microbiota and estimated the heritability of each taxon. For the MetS-related and heritable taxa, we further investigated their associations with the apolipoprotein A-V gene (APOA5) single nucleotide polymorphism (SNP) rs651821, which is known to be associated with triglyceride levels and MetS. RESULTS: Individuals with MetS had a lower gut microbiota diversity than healthy individuals. The abundances of several taxa were associated with MetS status; Sutterella, Methanobrevibacter and Lactobacillus were enriched in the MetS group, whereas Akkermansia, Odoribacter and Bifidobacterium were enriched in the healthy group. Among the taxa associated with MetS status, the phylum Actinobacteria, to which Bifidobacterium belongs, had the highest heritability (45.7%). Even after adjustment for MetS status, reduced abundances of Actinobacteria and Bifidobacterium were significantly linked to the minor allele at the APOA5 SNP rs651821. CONCLUSIONS: Our results suggest that an altered microbiota composition mediated by a specific host genotype can contribute to the development of MetS.

Merdimonas faecis gen. nov., sp. nov., isolated from human faeces.

A strictly anaerobic Gram-stain-positive, non-motile and non-spore-forming bacterial strain, BR31T, was isolated from a faecal sample of a healthy human. Bacterial colonies were ivory-coloured on GAM agar and composed of rod-shaped cells with rounded ends approximately 1.4-2.1×0.5-0.6 µm in size. According to comparative analysis based on 16S rRNA gene sequences, strain BR31T formed a distinct phylogenetic lineage that reflects a new genus within Clostridium cluster XIVa in the family Lachnospiraceae, with highest similarity to Eubacterium contortum DSM 3982T (94.6 %). The DNA G+C content was calculated to be 47.0 mol% from whole genome sequencing. Predicted genes associated with synthesis of teichuronic acid, polyamines, polar lipids and diaminopimelic acid were detected. The peptidoglycan contained meso-diaminopimelic acid and the main polar lipid detected was phosphatidylglycerol. The major metabolic end product of glucose was acetic acid, which was in agreement with those of most members of the family. However, the profile of major cellular fatty acids (C16 : 0, C14 : 0, summed feature 4 and C13 : 0) and overall enzyme activity demonstrated phenotypic differentiation of strain BR31T from other closely related genera. Thus, based on distinct phenotypic, phylogenetic, genotypic and chemotaxonomic characteristics, strain BR31T is considered to represent a novel species of a new genus, for which the name Merdimonas faecis gen. nov., sp. nov. is proposed. The type strain of Merdimonas faecis is BR31T (=KCTC 15482T=JCM 30748T).

Sellimonas intestinalis gen. nov., sp. nov., isolated from human faeces.

A Gram-stain-positive and obligately anaerobic bacterial strain, BR72T, forming ivory yellow colonies was isolated from a faecal sample of a healthy Korean woman. 16S rRNA gene sequence analysis indicated that strain BR72T belongs to Clostridium cluster XIVa and represents a distinct phyletic line within the family Lachnospiraceae. The most closely related strains were Clostridium nexile DSM 1787T (94.1 % 16S rRNA gene sequence similarity), Coprococcus comes ATCC 27758T (93.5 %), Ruminococcus torques ATCC 27756T (93.5 %), Ruminococcus lactaris ATCC 29176T (93.5 %), Clostridium aerotolerans DSM 5434T (93.1 %) and Eubacterium fissicatena DSM 3598T (92.9 %). The DNA G+C content of strain BR72T based on its genome sequence was 45.3 mol%. The major cellular fatty acids were C16 : 0, C14 : 0, and iso-C17 : 1 I and/or anteiso-C17 : 1 B. Acetic acid was produced from glucose fermentation. Other physiological and biochemical comparisons allowed the phenotypic differentiation of strain BR72T from the members of the family Lachnospiraceae. Based on the phylogenetic and phenotypic findings, this strain is considered to represent a novel species of a new genus belonging to the family Lachnospiraceae and the name Sellimonas intestinalis gen. nov., sp. nov. is proposed. The type strain of Sellimonas intestinalis is BR72T ( = KCTC 15479T = JCM 30749T).

Curcumin Shows Antiviral Properties against Norovirus.

Phytochemicals provide environmentally friendly and relatively inexpensive natural products, which could potentially benefit public health by controlling human norovirus (HuNoV) infection. In this study, 18 different phytochemicals were evaluated for antiviral effects against norovirus using murine norovirus (MNV) as a model for norovirus biology. Among these phytochemicals, curcumin (CCM) was the most potent anti-noroviral phytochemical, followed by resveratrol (RVT). In a cell culture infection model, exposure to CCM or RVT for 3 days reduced infectivity of norovirus by 91% and 80%, respectively. To confirm the antiviral capability of CCM, we further evaluated its antiviral efficacy at various doses (0.25, 0.5, 0.75, 1, and 2 mg/mL) and durations (short-term: 10, 30, 60, and 120 min; long-term: 1, 3, 7, and 14 days). The anti-noroviral effect of CCM was verified to occur in a dose-dependent manner. Additionally, we evaluated the inhibitory effect of each phytochemical on the replication of HuNoV using a HuNoV replicon-bearing cell line (HG23). Neither CCM nor RVT had a strong inhibitory effect on HuNoV replication, which suggests that their antiviral mechanism may involve viral entry or other life cycle stages rather than the replication of viral RNA. Our results demonstrated that CCM may be a promising candidate for development as an anti-noroviral agent to prevent outbreaks of foodborne illness.

Genetic associations and shared environmental effects on the skin microbiome of Korean twins.

BACKGROUND: The skin is the outermost layer of the human body and one of the key sites for host-microbe interactions. Both environmental and host genetic factors influence microbial communities in distinct anatomical niches, but little is known about their interplay in shaping the skin microbiome. Here, we investigate the heritable components of the skin microbiome and their association with host genetic factors. RESULTS: Based on our analysis of the microbiota from 45 individuals including monozygotic and dizygotic twins aged 26-55 years and their mothers, we found that skin microbial diversity was significantly influenced by age and skin pigmentation. Heritability analysis revealed genetic and shared environmental impacts on the skin microbiome. Furthermore, we observed a strong association between the abundance of Corynebacterium jeikeium and single nucleotide polymorphisms (SNPs) in the host FLG gene related to epidermal barrier function. CONCLUSION: This study reveals an intimate association of the human skin microbiome and host genes, and increases our understanding of the role of human genetic factors in establishing a microbial ecosystem on the body surface.

Effect of temperature and relative humidity on the survival of foodborne viruses during food storage.

Millions of people suffer from foodborne diseases throughout the world every year, and the importance of food safety has grown worldwide in recent years. The aim of this study was to investigate the survival of hepatitis A virus (HAV) and viral surrogates of human norovirus (HuNoV) (bacteriophage MS2 and murine norovirus [MNV]) in food over time. HAV, MNV, and MS2 were inoculated onto either the digestive gland of oysters or the surface of fresh peppers, and their survival on these food matrices was measured under various temperature (4°C, 15°C, 25°C, and 40°C) and relative humidity (RH) (50% and 70%) conditions. Inoculated viruses were recovered from food samples and quantified by a plaque assay at predetermined time points over 2 weeks (0, 1, 3, 7, 10, and 14 days). Virus survival was influenced primarily by temperature. On peppers at 40°C and at 50% RH, >4- and 6-log reductions of MNV and HAV, respectively, occurred within 1 day. All three viruses survived better on oysters. In addition, HAV survived better at 70% RH than at 50% RH. The survival data for HAV, MS2, and MNV were fit to three different mathematical models (linear, Weibull, and biphasic models). Among them, the biphasic model was optimum in terms of goodness of fit. The results of this study suggest that major foodborne viruses such as HAV and HuNoV can survive over prolonged periods of time with a limited reduction in numbers. Because a persistence of foodborne virus on contaminated foods was observed, precautionary preventive measures should be performed.

Enhancement of enteric adenovirus cultivation in a novel Ras-overexpressing cell line.

Enteric human adenoviruses (HAdVs; serotypes 40 and 41) have been identified as an emerging cause of drinking water contamination. Due to their fastidious characteristics, HAdVs are difficult to cultivate and therefore not detected easily by standard mammalian cell cultivation methods. Here we found that human embryonic kidney 293 cells, transformed transiently with Ras, enhanced HAdV replication by more than threefold. We also constructed a stable cell line overexpressing the Ras protein, 293-Ras, in which the replication of three HAdV strains of serotypes 40 and 41 was increased markedly. However, only HAdV replication was enhanced; infection of 293 and 293-Ras cells with human rhinivorus-6 showed no significant differences in replication rate. Infected 293-Ras cells exhibited an increased level and phosphorylation of extracellular regulated kinase (ERK). In addition, the Ras-mediated increase in HAdV replication was impaired by the mitogen-activated protein kinase/ERK kinase (MEK1) inhibitor U0126, suggesting direct involvement of the MEK1/ERK pathway in enhanced HAdV replication. Based on these results, we suggest that the 293-Ras cell line be used for the efficient detection and cultivation of HAdV strains in both clinical and environmental specimens.

Effect of metformin on metabolic improvement and gut microbiota.

Metformin is commonly used as the first line of medication for the treatment of metabolic syndromes, such as obesity and type 2 diabetes (T2D). Recently, metformin-induced changes in the gut microbiota have been reported; however, the relationship between metformin treatment and the gut microbiota remains unclear. In this study, the composition of the gut microbiota was investigated using a mouse model of high-fat-diet (HFD)-induced obesity with and without metformin treatment. As expected, metformin treatment improved markers of metabolic disorders, including serum glucose levels, body weight, and total cholesterol levels. Moreover, Akkermansia muciniphila (12.44%±5.26%) and Clostridium cocleatum (0.10%±0.09%) abundances increased significantly after metformin treatment of mice on the HFD. The relative abundance of A. muciniphila in the fecal microbiota was also found to increase in brain heart infusion (BHI) medium supplemented with metformin in vitro. In addition to the changes in the microbiota associated with metformin treatment, when other influences were controlled for, a total of 18 KEGG metabolic pathways (including those for sphingolipid and fatty acid metabolism) were significantly upregulated in the gut microbiota during metformin treatment of mice on an HFD. Our results demonstrate that the gut microbiota and their metabolic pathways are influenced by metformin treatment.

Antiviral properties of silver nanoparticles on a magnetic hybrid colloid.

Silver nanoparticles (AgNPs) are considered to be a potentially useful tool for controlling various pathogens. However, there are concerns about the release of AgNPs into environmental media, as they may generate adverse human health and ecological effects. In this study, we developed and evaluated a novel micrometer-sized magnetic hybrid colloid (MHC) decorated with variously sized AgNPs (AgNP-MHCs). After being applied for disinfection, these particles can be easily recovered from environmental media using their magnetic properties and remain effective for inactivating viral pathogens. We evaluated the efficacy of AgNP-MHCs for inactivating bacteriophage ΦX174, murine norovirus (MNV), and adenovirus serotype 2 (AdV2). These target viruses were exposed to AgNP-MHCs for 1, 3, and 6 h at 25°C and then analyzed by plaque assay and real-time TaqMan PCR. The AgNP-MHCs were exposed to a wide range of pH levels and to tap and surface water to assess their antiviral effects under different environmental conditions. Among the three types of AgNP-MHCs tested, Ag30-MHCs displayed the highest efficacy for inactivating the viruses. The ΦX174 and MNV were reduced by more than 2 log10 after exposure to 4.6 × 10(9) Ag30-MHCs/ml for 1 h. These results indicated that the AgNP-MHCs could be used to inactivate viral pathogens with minimum chance of potential release into environment.

Fermented Milk Containing Lacticaseibacillus rhamnosus SNU50430 Modulates Immune Responses and Gut Microbiota in Antibiotic-Treated Mice.

Antibiotics are used to control infectious diseases. However, adverse effects of antibiotics, such as devastation of the gut microbiota and enhancement of the inflammatory response, have been reported. Health benefits of fermented milk are established and can be enhanced by the addition of probiotic strains. In this study, we evaluated effects of fermented milk containing Lacticaseibacillus rhamnosus (L. rhamnosus) SNUG50430 in a mouse model with antibiotic treatment. Fermented milk containing 2 × 105 colony-forming units of L. rhamnosus SNUG50430 was administered to six week-old female BALB/c mice for 1 week. Interleukin (IL)-10 levels in colon samples were significantly increased (P < 0.05) compared to water-treated mice, whereas interferon-gamma (IFN-γ) and tumor necrosis factor alpha (TNF-α) were decreased, of mice treated with fermented milk containing L. rhamnosus SNUG50430-antibiotics-treated (FM+LR+Abx-treated) mice. Phylum Firmicutes composition in the gut was restored and the relative abundances of several bacteria, including the genera Coprococcus and Lactobacillus, were increased in FM+LR+Abx-treated mice compared to PBS+Abx-treated mice. Interestingly, abundances of genus Coprococcus and Lactobacillus were positively correlated with IL-5 and IL-10 levels (P < 0.05) in colon samples and negative correlated with IFN-γ and TNF-α levels in serum samples (P < 0.001). Acetate and butyrate were increased in mice with fermented milk and fecal microbiota of FM+LR+Abx-treated mice were highly enriched with butyrate metabolism pathway compared to water-treated mice (P < 0.05). Thus, fermented milk containing L. rhamnosus SNUG50430 was shown to ameliorate adverse health effects caused by antibiotics through modulating immune responses and the gut microbiota.

Strain-Specific Anti-Inflammatory Effects of Faecalibacterium prausnitzii Strain KBL1027 in Koreans.

Faecalibacterium prausnitzii is one of the most dominant commensal bacteria in the human gut, and certain anti-inflammatory functions have been attributed to a single microbial anti-inflammatory molecule (MAM). Simultaneously, substantial diversity among F. prausnitzii strains is acknowledged, emphasizing the need for strain-level functional studies aimed at developing innovative probiotics. Here, two distinct F. prausnitzii strains, KBL1026 and KBL1027, were isolated from Korean donors, exhibiting notable differences in the relative abundance of F. prausnitzii. Both strains were identified as the core Faecalibacterium amplicon sequence variant (ASV) within the healthy Korean cohort, and their MAM sequences showed a high similarity of 98.6%. However, when a single strain was introduced to mice with dextran sulfate sodium (DSS)-induced colitis, KBL1027 showed the most significant ameliorative effects, including alleviation of colonic inflammation and restoration of gut microbial dysbiosis. Moreover, the supernatant from KBL1027 elevated the secretion of IL-10 cytokine more than that of KBL1026 in mouse bone marrow-derived macrophage (BMDM) cells, suggesting that the strain-specific, anti-inflammatory efficacy of KBL1027 might involve effector compounds other than MAM. Through analysis of the Faecalibacterium pan-genome and comparative genomics, strain-specific functions related to extracellular polysaccharide biosynthesis were identified in KBL1027, which could contribute to the observed morphological disparities. Collectively, our findings highlight the strain-specific, anti-inflammatory functions of F. prausnitzii, even within the same core ASV, emphasizing the influence of their human origin.

Oral Administration of Limosilactobacillus reuteri KBL346 Ameliorates Influenza Virus A/PR8 Infection in Mouse.

Influenza virus infection is an important public-health concern because of its high transmissibility and potential for severe complications. To mitigate the severity and complications of influenza, probiotics containing Lactobacillus are used and generally recognized as safe. We evaluated the anti-influenza effect of Limosilactobacillus reuteri (L. reuteri) KBL346, isolated from the fecel sample of healthy South Koreans, in mice. BALB/c mice were orally administered live and heat-inactivated L. reuteri KBL346. After infection with influenza virus (A/Puerto Rico/8/34) 0.5 times the 50% lethal dose (LD50), body weight loss was improved and recovery was accelerated. Furthermore, L. reuteri KBL346 improved body weight loss and survival rate of mice infected with 4 times the LD50 of influenza virus. Heat-inactivated L. reuteri KBL346 reduced the viral titer in the lung and the plasma immunoglobulin G level. Expression levels of genes encoding inflammatory cytokines, such as interferon-γ and toll-like receptor 2 (Tlr2), were decreased in the lung tissues of mice administered L. reuteri KBL346. Live and heat-inactivated L. reuteri KBL346 increased the expression level of Adamts4, which promotes recovery after infection, and decreased that of Tlr2. The α-diversity of the gut microbiome was modulated by the administration of L. reuteri KBL346. In addition, the structure of the gut microbial community differed according to the degree of weight loss. L. reuteri KBL346 has the potential to alleviate disease severity and improve histopathological changes in mice infected with influenza A/PR8, suggesting its efficacy as a probiotic against influenza infection.

Lactobacillus acidophilus KBL409 Ameliorates Atopic Dermatitis in a Mouse Model.

Atopic dermatitis (AD) is a chronic inflammatory skin disease with repeated exacerbations of eczema and pruritus. Probiotics can prevent or treat AD appropriately via modulation of immune responses and gut microbiota. In this study, we evaluated effects of Lactobacillus acidophilus (L. acidophilus) KBL409 using a house dust mite (Dermatophagoides farinae)-induced in vivo AD model. Oral administration of L. acidophilus KBL409 significantly reduced dermatitis scores and decreased infiltration of immune cells in skin tissues. L. acidophilus KBL409 reduced in serum immunoglobulin E and mRNA levels of T helper (Th)1 (Interferon-γ), Th2 (Interleukin [IL]-4, IL-5, IL-13, and IL-31), and Th17 (IL-17A) cytokines in skin tissues. The anti-inflammatory cytokine IL-10 was increased and Foxp3 expression was up-regulated in AD-induced mice with L. acidophilus KBL409. Furthermore, L. acidophilus KBL409 significantly modulated gut microbiota and concentrations of short-chain fatty acids and amino acids, which could explain its effects on AD. Our results suggest that L. acidophilus KBL409 is the potential probiotic for AD treatment by modulating of immune responses and gut microbiota of host.

Acinetobacter kookii sp. nov., isolated from soil.

Two Gram-stain-negative, non-fermentative bacterial strains, designated 11-0202(T) and 11-0607, were isolated from soil in South Korea, and four others, LUH 13522, LUH 8638, LUH 10268 and LUH 10288, were isolated from a beet field in Germany, soil in the Netherlands, and sediment of integrated fish farms in Malaysia and Thailand, respectively. Based on 16S rRNA, rpoB and gyrB gene sequences, they are considered to represent a novel species of the genus Acinetobacter. Their 16S rRNA gene sequences showed greatest pairwise similarity to Acinetobacter beijerinckii NIPH 838(T) (97.9-98.4 %). They shared highest rpoB and gyrB gene sequence similarity with Acinetobacter johnsonii DSM 6963(T) and Acinetobacter bouvetii 4B02(T) (85.4-87.6 and 78.1-82.7 %, respectively). Strain 11-0202(T) displayed low DNA-DNA reassociation values (<40 %) with the most closely related species of the genus Acinetobacter. The six strains utilized azelate, 2,3-butanediol, ethanol and dl-lactate as sole carbon sources. Cellular fatty acid analyses showed similarities to profiles of related species of the genus Acinetobacter: summed feature 3 (C16 : 1ω7c, C16 : 1ω6c; 24.3-27.2 %), C18 : 1ω9c (19.9-22.1 %), C16 : 0 (15.2-22.0 %) and C12 : 0 (9.2-14.2 %). On the basis of the current findings, it is concluded that the six strains represent a novel species, for which the name Acinetobacter kookii sp. nov. is proposed. The type strain is 11-0202(T) ( = KCTC 32033(T) = JCM 18512(T)).

Performance characteristics of qPCR assays targeting human- and ruminant-associated bacteroidetes for microbial source tracking across sixteen countries on six continents.

Numerous quantitative PCR assays for microbial fecal source tracking (MST) have been developed and evaluated in recent years. Widespread application has been hindered by a lack of knowledge regarding the geographical stability and hence applicability of such methods beyond the regional level. This study assessed the performance of five previously reported quantitative PCR assays targeting human-, cattle-, or ruminant-associated Bacteroidetes populations on 280 human and animal fecal samples from 16 countries across six continents. The tested cattle-associated markers were shown to be ruminant-associated. The quantitative distributions of marker concentrations in target and nontarget samples proved to be essential for the assessment of assay performance and were used to establish a new metric for quantitative source-specificity. In general, this study demonstrates that stable target populations required for marker-based MST occur around the globe. Ruminant-associated marker concentrations were strongly correlated with total intestinal Bacteroidetes populations and with each other, indicating that the detected ruminant-associated populations seem to be part of the intestinal core microbiome of ruminants worldwide. Consequently tested ruminant-targeted assays appear to be suitable quantitative MST tools beyond the regional level while the targeted human-associated populations seem to be less prevalent and stable, suggesting potential for improvements in human-targeted methods.