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  • 1.
    Hasslöf, Pamela
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Pediatric Dentistry.
    Hedberg, Maria
    Umeå University, Faculty of Medicine, Department of Odontology, Oral Microbiology.
    Twetman, Svante
    Stecksén-Blicks, Christina
    Umeå University, Faculty of Medicine, Department of Odontology, Pediatric Dentistry.
    Growth inhibition of oral mutans streptococci and candida by commercial probiotic lactobacilli: an in vitro study2010In: BMC Oral Health, ISSN 1472-6831, E-ISSN 1472-6831, Vol. 10, p. 18-Article in journal (Refereed)
    Abstract [en]

    The selected probiotic strains showed a significant but somewhat varying ability to inhibit growth of oral mutans streptococci and Candida albicans in vitro.

  • 2.
    Hedberg, Maria
    et al.
    Umeå University, Faculty of Medicine, Odontology, Oral Microbiology.
    Asikainen, Sirkka
    Umeå University, Faculty of Medicine, Odontology, Oral Microbiology.
    Growth inhibition of Porphyromonas gingivalis biofilm by lactobacilli2007Report (Other academic)
    Abstract [en]

    Background. Chronic periodontitis is one of the most common infectious diseases of the oral cavity. Dental plaque contains a mix of oral bacteria, and grows as biofilm on tooth surfaces. One of the bacterial species associated with periodontitis is Porphyromonas gingivalis, a Gram-negative anaerobic rod. Lactobacilli are used in probiotic products and are known to play an important role in the management of health by stimulating the immune system and contributing to the balance of the normal microflora. The knowledge of probiotic effects on oral bacteria is at present limited.

    Purpose. Lactobacillus reuteri, and Lactobacillus acidophilus are two species used in different probiotic products. In the presence of glycerol L. reuteri produces an antimicrobial product, 3-hydroxypropionaldehyd, also called reuterin. The purpose of the study was to examine the impact of L. reuteri and L. acidophilus on biofilm formed by P. gingivalis.

    Methods. To study whether L. reuteri and L. acidophilus had ability to alter the biofilm formation of P. gingivalis, 108 CFU/mL P. gingivalis and 108 CFU/mL of one of the lactobacilli were co-cultured in Brucella broth using cell-culture plates. After 48 h incubation the broth was removed and the biofilm studied by microscopy, crystal violet staining with subsequent absorbance measurements at 590 nm. Viable bacterial cells were determined in the biofilm and in the removed growth medium.

    Results. P. gingivalis and L. reuteri cultured individually formed heavy layers of biofilm (A590=2.1-3.1), whereas L. acidophilus gave a very thin layer (A590=0.21-0.35). In the biofilm competition assay, the level of viable P. gingivalis cells were reduced by at least 3 logs regardless the addition of glycerol when co-cultured with L. reuteri or L. acidophilus. In presence of glycerol, both P. gingivalis and L. reuteri were reduced below the detection level after 48 h incubation.

    Even though P. gingivalis cultured as single species formed a dense biofilm this was strongly reduced when co-cultured with L. acidophilus.

    Conclusion. In summary, the observed glycerol-dependent growth inhibition of P. gingivalis by L. reuteri seemed to be due to reuterin production. Competition in the biofilm model appeared to favor both lactobacillus species tested at the expense of P. gingivalis. The lactobacilli were able to strongly inhibit or suppress the growth of a major periodontal pathogen in the biofilm-competition assay.

  • 3.
    Hedberg, Maria E.
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Israelsson, Anne
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Moore, Edward R. B.
    Svensson-Stadler, Liselott
    Wai, Sun Nyunt
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Pietz, Grzegorz
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Sandström, Olof
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Hernell, Olle
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Hammarström, Marie-Louise
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Hammarstrom, Sten
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Prevotella jejuni sp nov., isolated from the small intestine of a child with coeliac disease2013In: International Journal of Systematic and Evolutionary Microbiology, ISSN 1466-5026, E-ISSN 1466-5034, Vol. 63, no 11, p. 4218-4223Article in journal (Refereed)
    Abstract [en]

    Five obligately anaerobic, Gram-stain-negative, saccharolytic and proteolytic, non-spore-forming bacilli (strains CD3 :27, CD3 :28(T), CD3 :33, CD3 :32 and CD3 :34) are described. All five strains were isolated from the small intestine of a female child with coeliac disease. Cells of the five strains were short rods or coccoid cells with longer filamentous forms seen sporadically. The organisms produced acetic acid and succinic acid as major metabolic end products. Phylogenetic analysis based on comparative 16S rRNA gene sequence analysis revealed close relationships between CD3 : 27, CD3 :28(T) and CD3 :33, between CD3 :32 and Prevotella histicola CCUG 55407(T), and between CD3 :34 and Prevotella melaninogenica CCUG 4944B(T). Strains CD3 : 27, CD3 :28(T) and CD3 :33 were clearly different from all recognized species within the genus Prevotella and related most closely to but distinct from P. melaninogenica. Based on 16S rRNA, RNA polymerase) beta-subunit (rpoB) and 60 kDa chaperonin protein subunit (cpn60) gene sequencing, and phenotypic, chemical and biochemical properties, strains CD3 :27, CD3 :28(T) and CD3 :33 are considered to represent a novel species within the genus Prevotella, for which the name Prevotella jejuni sp. nov. is proposed. Strain CD3 : 28(T) (=CCUG 60371(T)=DSM 26989(T)) is the type strain of the proposed novel species. All five strains were able to form homologous aggregates, in which tube-like structures were connecting individual bacteria cells. The five strains were able to bind to human intestinal carcinoma cell lines at 37 degrees C.

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  • 4.
    Hedberg, Maria E
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Moore, Edward RB
    Svensson-Stadler, Liselott
    Hörstedt, Per
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Baranov, Vladimir
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Immunology.
    Hernell, Olle
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Wai, Sun Nyunt
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Hammarström, Sten
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Hammarström, Marie-Louise
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Lachnoanaerobaculum a new genus in Lachnospiraceae; characterization of Lachnoanaerobaculum umeaense gen. nov., sp. nov., isolated from human small intestine, Lachnoanaerobaculum orale gen. nov., sp. nov., isolated from saliva and reclassification of Eubacterium saburreum (Prevot) Holdeman and Moore 1970 as Lachnoanaerobaculum saburreum comb. nov.2012In: International Journal of Systematic and Evolutionary Microbiology, ISSN 1466-5026, E-ISSN 1466-5034, Vol. 62, no 11, p. 2685-2690Article in journal (Refereed)
    Abstract [en]

    Two new obligately anaerobic Gram-positive, saccharolytic and non-proteolytic spore-forming bacilli (strain CD3:22 and N1) are described. Strain CD3:22 was isolated from a biopsy of the small intestine of a child with celiac disease and strain N1 from the saliva of a healthy young man. The cells of both strains were observed to be filamentous with lengths of approximately 5 to >20 µm, some of them curving and with swellings. The novel organisms produced H2S, NH3, butyric acid and acetic acid as major metabolic end products. Phylogenetic analyses, based on comparative 16S rRNA gene sequencing, revealed close relationships (98 % sequence similarity) between the two isolates, as well as the type strain of Eubacterium saburreum CCUG 28089T and four other Lachnospiraceae bacterium/E. saburreum-like organisms. This group of bacteria were clearly different from any of the 19 known genera in the family Lachnospiraceae. While Eubacterium spp. are reported to be non-spore-forming, reanalysis of E. saburreum CCUG 28089T confirmed that the bacterium, indeed, is able to form spores. Based on 16S rRNA gene sequencing, phenotypic and biochemical properties, CD3:22 (CCUG 58757T) and N1 (CCUG 60305T) represent new species of a new and distinct genus, named Lachnoanaerobaculum, in the family Lachnospiraceae [within the order Clostridiales, class Clostridia, phylum Firmicutes]. Strain CD3:22 is the type strain of the type species, Lachnoanaerobaculum umeaense gen. nov., sp. nov., of the proposed new genus. Strain N1 is the type strain of the species, Lachnoanaerobaculum orale gen. nov., sp. nov. Moreover, E. saburreum CCUG 28089T is reclassified as Lachnoanaerobaculum saburreum comb. nov.

  • 5.
    Hedberg, Maria
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Hammarström, Marie-Louise
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Hernell, Olle
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Baranov, Vladimir
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Immunology.
    Wai, Sun Nyunt
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Moore, Edward
    Sahlgrenska Universitetssjukhuset, Göteborgs Universitet.
    Hammarström, Sten
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Clostridiales bacterium CD3:22-an anaerobic spore-forming bacterium isolated from small intestine in a celiac disease patient2010Report (Other academic)
  • 6.
    Hedberg, Maria
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Oral Microbiology.
    Hasslöf, Pamela
    Umeå University, Faculty of Medicine, Department of Odontology, Pediatric Dentistry.
    Sjöström, I
    Umeå University, Faculty of Medicine, Department of Odontology, Pediatric Dentistry.
    Twetman, S
    Stecksén-Blicks, Christina
    Umeå University, Faculty of Medicine, Department of Odontology, Pediatric Dentistry.
    Sugar fermentation in probiotic bacteria: an in vitro study2008In: Oral Microbiology and Immunology, ISSN 0902-0055, E-ISSN 1399-302X, Vol. 23, no 6, p. 482-485Article in journal (Refereed)
    Abstract [en]

    INTRODUCTION: Food supplemented with probiotic bacteria is a rapidly growing sector of the market. The aim of the present study was to evaluate and compare the acid production of selected probiotic strains available in commercial products.

    METHODS: Six Lactobacillus strains (Lactobacillus plantarum 299v and 931; Lactobacillus rhamnosus GG and LB21; Lactobacillus paracasei subsp. paracasei F19, and Lactobacillus reuteri PTA 5289) were cultivated at 37 degrees C in an anaerobic atmosphere on Man, Rogosa, Shape (MRS) agar for 48 h or MRS broth for 16 h. After centrifugation, the cells were washed and resuspended in sterile phosphate-buffered saline and immediately subjected to a fermentation assay with 12 different carbohydrates (nine sugars and three sugar alcohols) in microtiter plates with a pH indicator. The plates were examined for color changes after 24, 48, and 72 h of incubation under aerobic and anaerobic conditions. Three scores were used: negative (pH > 6.8); weak (pH 5.2-6.8), and positive (pH < 5.2). The strains were characterized with the API 50 CH system to confirm their identity.

    RESULTS: L. plantarum fermented all the sugars except for melibiose, raffinose, and xylitol. Both L. rhamnosus strains were generally less active although L. rhamnosus GG was slightly more active than strain LB21 in the 5% CO(2) setting. The latter strain exhibited negative reactions for sucrose, maltose, arabinose, and sorbitol under anaerobic conditions. The assays with L. paracasei and L. reuteri had negative or weak reactions for all tested sugars under both aerobic and anaerobic conditions.

    CONCLUSION: The metabolic capacity to form acid from dietary sugars differed significantly between the various probiotic strains.

  • 7.
    Hedberg, Maria
    et al.
    Umeå University, Faculty of Medicine, Odontology, Oral Microbiology.
    Hasslöf, Pamela
    Umeå University, Faculty of Medicine, Odontology, Pediatric Dentistry.
    Sjöström, Inger
    Umeå University, Faculty of Medicine, Odontology, Pediatric Dentistry.
    Stecksén-Blicks, Christina
    Umeå University, Faculty of Medicine, Odontology, Pediatric Dentistry.
    Twetman, Svante
    University of Copenhagen.
    In vitro inhibition of mutans streptococci by probiotic lactobacilli2009Report (Other academic)
  • 8.
    Hedberg, Maria
    et al.
    Umeå University, Faculty of Medicine, Odontology, Oral Microbiology.
    Karched, Maribasappa
    Asikainen, Sirkka
    Umeå University, Faculty of Medicine, Odontology, Oral Microbiology.
    In-vitro growth inhibition of periodontitis-associated species by Lactobacillus reuteri2006Report (Other academic)
    Abstract [en]

    Purpose. Lactobacillus reuteri, a species used in probiotic products, produces in vitro a bacteriocin, reuterin, in the presence of glycerol. The purpose of the study was to investigate in vitro whether L. reuteri strains inhibit the growth of periodontal pathogens.

    Methods. The inhibition study was based on a disk-diffusion method. The periodontitis-associated bacteria were pre-grown for 20 h in Brucella broth or Brucella blood agar at 37oC in anaerobic atmosphere. Standardization of bacterial inocula used in the assay was made by determinations of optical density, microscopic counting of cells, and viable count. Brucella blood agar plates, without or with glycerol (100 mM), were seeded with standardized inocula of the periodontal pathogens Fusobacterium nucleatum (IDH 4186), Porphyromonas gingivalis (ATCC 33277), Prevotella intermedia (ATCC 25611), and Actinobacillus actinomycetemcomitans (SA 1398). The lactobacilli L. reuteri ATCC 55730 and L. reuteri PTA 5289 were grown for 16 h in MRS broth. A 20-L aliquot of the suspension containing 107 CFU/mL was used to soak 6-mm paper disks, which were placed on Brucella agar plates (diameter 14 cm), seeded with each periodontal pathogen separately. The plates were then incubated for 3 - 7 days in anaerobic atmosphere at 37oC before measuring the inhibition zones.

    Results. On Brucella blood agar plates seeded with periodontal pathogens, no inhibition zones were seen around the paper discs. When glycerol was added to the agar, zones of 26 to 118 mm appeared. Sizes of the zones depended on the L. reuteri strain, the periodontal pathogen, and the sizes of their inocula. L. reuteri PTA 5289 had a stronger (7-30%) inhibitory effect than L. reuteri ATCC 55730 on all periodontal species. P. gingivalis was the most susceptible species among the tested strains.

    Conclusion. Both L. reuteri strains strongly inhibited or suppressed the growth of the tested periodontitis-associated bacteria in the presence of glycerol. The inhibitory activity of L. reuteri PTA 5289 was consistently higher than that of L. reuteri ATCC 55730. The results suggest that the inhibition activity of the tested lactobacilli was related to reuterin.

  • 9.
    Hedberg, Maria
    et al.
    Umeå University, Faculty of Medicine, Odontology, Oral Microbiology.
    Nord, Carl Erik
    Karoloinska Institute,.
    Anaerobic bacteria2008In: Antimicrobial therapy and vaccines: volume I: Microbes, New York: Apple Trees Production, LLC , 2008, 3rdChapter in book (Other academic)
  • 10.
    Johansson, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Hedberg, Maria E.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Fermented rye bran as biocide replacement in paper production2024In: 4th international conference strategies toward green deal implementation water, raw materials & energy: Abstract book / [ed] Marzena Smol, Cracow: Publishing House, Mineral and Energy Economy Research Institute, Polish Academy of Sciences , 2024, p. 78-78Conference paper (Refereed)
    Abstract [en]

    Microbial contamination causes environmental and costly problems in paper production. Today, chemical-based biocides are used to control these problems. We have developed a biocide substitute that consists of fermented rest products from the cereal industry. Rye bran is a suitable nutrient for growth of a selected strain of Lactiplantibacillus plantarum. Previous studies have shown that fermented rye bran contains bioactive metabolites that powerfully limit virtually all bacterial growth. The cereals also contain fibres with potential to be a supplement in the raw material (pulp) of paper production. Our intention with this study was to investigate the potential of fermented rye bran as an antibacterial raw material in paper production. We will specifically determine the antibacterial effect of fermented rye bran on bacterial strains isolated from pulp and process water at a paper mill. In addition, to analyse the effect of the single metabolites discovered in the fermented rye bran. The results showed that fermented rye bran inhibited growth of the majority of the bacterial strains isolated from the paper mill. The pure metabolites showed also antibacterial properties, but less potent in comparison to the crude fermented rye bran product. The Lactobacillus strain used in the present study was resistant to all the tested metabolites. In conclusion, fermented rye bran shows properties indicating potential to be used as a bioactive raw material, limiting the need to add antimicrobial chemicals in paper production

  • 11.
    Johansson, Anders
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Hedberg, Maria E.
    Umeå University, Faculty of Medicine, Department of Odontology.
    Industrial rest materials as biocide replacement in paper production2024In: Research workshop on bacillus in clinical and agricultural environments, German Multidisciplinary Publishing Center , 2024, p. 15-15Conference paper (Refereed)
    Abstract [en]

    Microbial contamination causes environmental and costly problems in paper production (gas formation in stored pulp, and biofilm/slime) and waste water systems (biofilm formation causing corrosion of the pipes). Today, chemical-based biocides are used to control these problems. We have developed a biocide substitute consisting of industrial rest products; rye bran or spruce bark. Rye bran is a suitable nutrient for growth of a selected strain of Lactiplantibacillus plantarum. Previous studies have shown that fermented rye bran, as well as spruce bark extracts, contains bioactive metabolites with the power to limit virtually all bacterial growth. These products also contain fibres with potential to be a supplement as raw material in the pulp.

    Our intention with this study was to investigate the potential of these rest materials as an antibacterial raw material in paper production. We will specifically determine the antibacterial effect on strains isolated from pulp, process water from the paper mill, and waste water pipes. In addition, likewise analyse the antimicrobial activity of single metabolites discovered in the crude extracts. The results so far, show that the products efficiently inhibit growth of the bacterial strains isolated from waste water and the paper mill. The pure metabolites showed also antibacterial properties, but were less potent as compared to the crude products. The Lactiplantiobacillus strain, used to ferment the rye bran in the present study, was resistant to all the tested products.

    In conclusion, fermented rye bran and spruce bark extracts show properties indicating a potential to be used as a bioactive raw material, limiting the need of adding synthetic biocides in paper production and waste water systems.

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    Bacillus abstract
  • 12.
    Koistinen, Ville M.
    et al.
    Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland; Food Chemistry and Food Development Unit, Department of Biochemistry, University of Turku, Turku, Turku, Finland; Afekta Technologies Ltd., Kuopio, Finland.
    Hedberg, Maria
    Umeå University, Faculty of Medicine, Department of Odontology.
    Shi, Lin
    Division of Food and Nutrition Science, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden; College of Food Engineering and Nutritional Science, Shaanxi Normal University, Xi'an, China.
    Johansson, Anders
    Umeå University, Faculty of Medicine, Department of Odontology.
    Savolainen, Otto
    Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland; Division of Food and Nutrition Science, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden.
    Lehtonen, Marko
    School of Pharmacy, University of Eastern Finland, Kuopio, Finland.
    Aura, Anna‐Marja
    VTT Technical Research Centre of Finland Ltd., Espoo, Finland.
    Hanhineva, Kati
    Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland; Food Chemistry and Food Development Unit, Department of Biochemistry, University of Turku, Turku, Turku, Finland; Division of Food and Nutrition Science, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden.
    Landberg, Rikard
    Division of Food and Nutrition Science, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden.
    Metabolite pattern derived from Lactiplantibacillus plantarum: fermented rye foods and in vitro gut fermentation synergistically inhibits bacterial growth2022In: Molecular Nutrition & Food Research, ISSN 1613-4125, E-ISSN 1613-4133, Vol. 66, no 21, article id 2101096Article in journal (Refereed)
    Abstract [en]

    Scope: Fermentation improves many food characteristics using microbes, such as lactic acid bacteria (LAB). Recent studies suggest fermentation may also enhance the health properties, but mechanistic evidence is lacking. We aimed to identify a metabolite pattern reproducibly produced during sourdough and in vitro colonic fermentation of various whole-grain rye products and how it affects the growth of bacterial species of potential importance to health and disease.

    Methods and results: We used Lactiplantibacillus plantarum DSMZ 13890 strain, previously shown to favour rye as its substrate. Using LC-MS metabolomics, we found seven microbial metabolites commonly produced during the fermentations, including dihydroferulic acid, dihydrocaffeic acid, and five amino acid metabolites, and stronger inhibition was achieved when exposing the bacteria to a mixture of the metabolites in vitro compared to individual compound exposures.

    Conclusion: Our study suggests that metabolites produced by LAB may synergistically modulate the local microbial ecology, such as in the gut. This could provide new hypotheses on how fermented foods influence human health via diet–microbiota interactions.

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  • 13. Moore, Edward R.B.
    et al.
    Salvà‐Serra, Francisco
    Jaén‐Luchoro, Daniel
    Hammarström, Marie-Louise
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Hammarström, Sten
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Hedberg, Maria E.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology.
    Lachnoanaerobaculum2021In: Bergey's Manual of Systematics of Archaea and Bacteria (BMSAB), John Wiley & Sons, 2021Chapter in book (Refereed)
    Abstract [en]

    The genus Lachnoanaerobaculum comprises obligately anaerobic, Gram-stain-positive chemoorganotrophic, saccharolytic, and nonproteolytic bacilli. Cells are spore forming, rod shaped, and filamentous, 5 to greater than 20 μm in length, some cells with curving and swelling. All species of the genus grow with glucose as the sole carbon source. All species produce H2S, NH3, butyric acid, acetic acid, and lactic acid as metabolic end products. The predominant cellular fatty acids are C14:0, C16:0, and C18:1 ω7c DMA. The G + C contents of genomic DNA of the species are 35.0–37.8 mol%. Phylogenetic relationships of the species of Lachnoanaerobaculum, based on comparative 16S rRNA gene sequence analyses, indicate that they cluster within the phylum Firmicutes, within the family Lachnospiraceae, and exhibit a clear delineation to the other genera of the family, with a relatively close relationship to Johnsonella species. The first described strain of Lachnoanaerobaculum umeaense, the type species of the genus, was isolated from the jejunal mucosa of a child with coeliac disease. Strains of the species of Lachnoanaerobaculum are typically found in intestinal microbiota and oral microbiota of the human microbiome, isolated from the human gut, saliva, blood, amniotic fluid, and, predominantly, from the oral cavity.

  • 14.
    Ou, Gangwei
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Hedberg, Maria
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Hörstedt, Per
    Umeå University, Faculty of Medicine, Department of Medical Biosciences, Pathology.
    Baranov, Vladimir
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Immunology.
    Forsberg, Göte
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Drobni, Mirva
    Umeå University, Faculty of Medicine, Department of Odontology, Cariology.
    Sandström, Olof
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Wai, Sun Nyunt
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Johansson, Ingegerd
    Umeå University, Faculty of Medicine, Department of Odontology, Cariology.
    Hammarström, Marie-Louise
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Hernell, Olle
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Hammarström, Sten
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Proximal small intestinal microbiota and identification of rod-shaped bacteria associated with childhood celiac disease2009In: American Journal of Gastroenterology, ISSN 0002-9270, E-ISSN 1572-0241, Vol. 104, no 12, p. 3058-3067Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: Alterations in the composition of the microbiota in the intestine may promote development of celiac disease (CD). Using scanning electron microscopy (SEM) we previously demonstrated that rod-shaped bacteria were present on the epithelium of proximal small intestine in children with CD but not in controls. In this study we characterize the microbiota of proximal small intestine in children with CD and controls and identify CD-associated rod-shaped bacteria. METHODS: Proximal small intestine biopsies from 45 children with CD and 18 clinical controls were studied. Bacteria were identified by 16S rDNA sequencing in DNA extracted from biopsies washed with buffer containing dithiothreitol to enrich bacteria adhering to the epithelial lining, by culture-based methods and by SEM and transmission electron microscopy. RESULTS: The normal, mucosa-associated microbiota of proximal small intestine was limited. It was dominated by the genera Streptococcus and Neisseria, and also contained Veillonella, Gemella, Actinomyces, Rothia, and Haemophilus. The proximal small intestine microbiota in biopsies from CD patients collected during 2004-2007 differed only marginally from that of controls, and only one biopsy (4%) had rod-shaped bacteria by SEM (SEM+). In nine frozen SEM+ CD biopsies from the previous study, microbiotas were significantly enriched in Clostridium, Prevotella, and Actinomyces compared with SEM- biopsies. Bacteria of all three genera were isolated from children born during the Swedish CD epidemic. New Clostridium and Prevotella species and Actinomyces graevenitzii were tentatively identified. CONCLUSIONS: Rod-shaped bacteria, probably of the indicated species, constituted a significant fraction of the proximal small intestine microbiota in children born during the Swedish CD epidemic and may have been an important risk factor for CD contributing to the fourfold increase in disease incidence in children below 2 years of age during that time.

  • 15.
    Pietz, Grzegorz
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    De, Rituparna
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Hedberg, Maria
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Sjöberg, Veronika
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Sandström, Olof
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Hernell, Olle
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Hammarström, Sten
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Hammarström, Marie-Louise
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Immunopathology of childhood celiac disease: Key role of intestinal epithelial cells2017In: PLOS ONE, E-ISSN 1932-6203, Vol. 12, no 9, article id e0185025Article in journal (Refereed)
    Abstract [en]

    BACKGROUND & AIMS: Celiac disease is a chronic inflammatory disease of the small intestine mucosa due to permanent intolerance to dietary gluten. The aim was to elucidate the role of small intestinal epithelial cells in the immunopathology of celiac disease in particular the influence of celiac disease-associated bacteria.

    METHODS: Duodenal biopsies were collected from children with active celiac disease, treated celiac disease, and clinical controls. Intestinal epithelial cells were purified and analyzed for gene expression changes at the mRNA and protein levels. Two in vitro models for human intestinal epithelium, small intestinal enteroids and polarized tight monolayers, were utilized to assess how interferon-γ, interleukin-17A, celiac disease-associated bacteria and gluten influence intestinal epithelial cells.

    RESULTS: More than 25 defense-related genes, including IRF1, SPINK4, ITLN1, OAS2, CIITA, HLA-DMB, HLA-DOB, PSMB9, TAP1, BTN3A1, and CX3CL1, were significantly upregulated in intestinal epithelial cells at active celiac disease. Of these genes, 70% were upregulated by interferon-γ via the IRF1 pathway. Most interestingly, IRF1 was also upregulated by celiac disease-associated bacteria. The NLRP6/8 inflammasome yielding CASP1 and biologically active interleukin-18, which induces interferon-γ in intraepithelial lymphocytes, was expressed in intestinal epithelial cells.

    CONCLUSION: A key factor in the epithelial reaction in celiac disease appears to be over-expression of IRF1 that could be inherent and/or due to presence of undesirable microbes that act directly on IRF1. Dual activation of IRF1 and IRF1-regulated genes, both directly and via the interleukin-18 dependent inflammasome would drastically enhance the inflammatory response and lead to the pathological situation seen in active celiac disease.

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  • 16.
    Pietz, Grzegorz
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Israelsson, Anne
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Hedberg, Maria
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Sandström, Olof
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Hernell, Olle
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Nyunt Wai, Sun
    Umeå University, Faculty of Medicine, Department of Molecular Biology (Faculty of Medicine).
    Hammarström, Marie-Louise
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Hammarström, Sten
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Influences of celiac disease associated bacteria on functions of intestinal epithelium: an in vitro studyManuscript (preprint) (Other academic)
  • 17.
    Sjöberg, Veronika
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Sandström, Olof
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Hedberg, Maria
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Hammarström, Sten
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Hernell, Olle
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Paediatrics.
    Hammarström, Marie-Louise
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Immunology/Immunchemistry.
    Intestinal T-cell responses in celiac disease: impact of celiac disease associated bacteria2013In: PLOS ONE, E-ISSN 1932-6203, Vol. 8, no 1, p. e53414-Article in journal (Refereed)
    Abstract [en]

    A hallmark of active celiac disease (CD), an inflammatory small-bowel enteropathy caused by permanent intolerance to gluten, is cytokine production by intestinal T lymphocytes. Prerequisites for contracting CD are that the individual carries the MHC class II alleles HLA-DQ2 and/or HLA-DQ8 and is exposed to gluten in the diet. Dysbiosis in the resident microbiota has been suggested to be another risk factor for CD. In fact, rod shaped bacteria adhering to the small intestinal mucosa were frequently seen in patients with CD during the "Swedish CD epidemic" and bacterial candidates could later be isolated from patients born during the epidemic suggesting long-lasting changes in the gut microbiota. Interleukin-17A (IL-17A) plays a role in both inflammation and anti-bacterial responses. In active CD IL-17A was produced by both CD8(+) T cells (Tc17) and CD4(+) T cells (Th17), with intraepithelial Tc17 cells being the dominant producers. Gluten peptides as well as CD associated bacteria induced IL-17A responses in ex vivo challenged biopsies from patients with inactive CD. The IL-17A response was suppressed in patients born during the epidemic when a mixture of CD associated bacteria was added to gluten, while the reverse was the case in patients born after the epidemic. Under these conditions Th17 cells were the dominant producers. Thus Tc17 and Th17 responses to gluten and bacteria seem to pave the way for the chronic disease with interferon-γ-production by intraepithelial Tc1 cells and lamina propria Th1 cells. The CD associated bacteria and the dysbiosis they might cause in the resident microbiota may be a risk factor for CD either by directly influencing the immune responses in the mucosa or by enhancing inflammatory responses to gluten.

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  • 18. Soki, Jozsef
    et al.
    Hedberg, Maria
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Biomedical Laboratory Science.
    Patrick, Sheila
    Balint, Balazs
    Herczeg, Robert
    Nagy, Istvan
    Hecht, David W.
    Nagy, Elisabeth
    Urban, Edit
    Emergence and evolution of an international cluster of MDR Bacteroides fragilis isolates2016In: Journal of Antimicrobial Chemotherapy, ISSN 0305-7453, E-ISSN 1460-2091, Vol. 71, no 9, p. 2441-2448Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to examine the antibiotic resistance profiles, antibiotic resistance mechanisms and possible 'clonal' nature of some MDR Bacteroides fragilis strains that simultaneously harboured cfiA, nimB, IS1186 and IS4351. Antibiotic susceptibilities were determined by Etests and antibiotic resistance genes and different genetic elements were detected by applying PCR methods. The environments of the cfiA and nimB genes were also determined by sequencing. The transferability of the cfiA, nimB and tet(Q) genes was tested by conjugation. The genetic relatedness of the test strains was tested by ERIC-PCR or PFGE. The complete genome sequences of two strains (B. fragilis BF8 and O:21) were determined by next-generation sequencing. Most of the seven B. fragilis strains tested displayed multidrug resistance phenotypes; five strains were resistant to at least five types of antibiotics. Besides the common genetic constitution, ERIC-PCR implied high genetic relatedness. Similarities in some of the antibiotic resistance mechanisms [carbapenems (cfiA) and metronidazole (nimB)] also confirmed their common origin, but some other resistance mechanisms {MLSB [erm(F)] and tetracycline [tet(Q)]} and PFGE typing revealed differences. In B. fragilis BF8 and O:21, erm(F) and tet(X) genes were found with IS4351 borders, thus constituting Tn4351. All the strains were tet(Q) positive and transferred this gene in conjugation experiments, but not the cfiA and nimB genes. An international cluster of MDR B. fragilis strains has been identified and characterized. This 'clone' may have emerged early in the evolution of division II B. fragilis strains, which was suggested by the low-complexity ERIC profiles and differences in the PFGE patterns.

  • 19.
    Sóki, J.
    et al.
    University of Szeged.
    Edwards, R.
    Hedberg, Maria
    Umeå University, Faculty of Medicine, Department of Odontology, Oral Microbiology.
    Fang, H.
    Nagy, E.
    Nord, C. E.
    Examination of cfiA-mediated carbapenem resistance in Bacteroides fragilis strains from a European antibiotic susceptibility survey2006In: International Journal of Antimicrobial Agents, ISSN 0924-8579, E-ISSN 1872-7913, Vol. 28, no 6, p. 497-502Article in journal (Refereed)
    Abstract [en]

    Of 1284 Bacteroides strains collected in Europe in 2000 for antibiotic susceptibility surveillance, 65 isolates displayed imipenem minimum inhibitory concentrations (MICs) > or =1 mg/L and were chosen for a thorough analysis of their resistance mechanism. Twenty-five of the isolates were positive for the cfiA carbapenem resistance gene. The resistance rates were 0.8% and 1.3% for imipenem and meropenem, respectively. In six of the strains, insertion sequence (IS) elements (IS613, IS614B, IS1186 and IS1187) activated the cfiA gene. However, other strains displayed at least elevated carbapenem MICs or were carbapenem resistant and produced measurable carbapenemase activities but did not harbour IS elements in the region upstream of the cfiA gene. The major determinant of carbapenem resistance in Bacteroides fragilis is production of CfiA metallo-beta-lactamase via activation of the cfiA gene by IS elements (higher level resistance) or by activation of its putative own promoter.

  • 20.
    Sóki, József
    et al.
    University of Szeged, Hungary.
    Hedberg, Maria
    Umeå University, Faculty of Medicine, Department of Odontology, Oral Microbiology.
    Urbán, Edith
    University of Szeged, Hungary.
    Terhes, G
    University of Szeged, Hungary.
    Nagy, Elisabeth
    University of Szeged, Hungary.
    Description of bacteroides strains showing hetero-resistance to cefoxitin and carbapenems2008Report (Other academic)
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