6th Theodor Escherich Symposium

28th - 29th November 2019

ABSTRACT BOOK

Mit freundlicher Unterstützung durch Bristol-Myers Squibb

Day 1 Thursday 28.11.2019

Start End Topic/Title Speaker

8:15 8:50 Registration and setup

8:50 9:00 Welcome note Caroline Schober-Trummler, Christine Moissl-Eichinger

Chairs: Torben Kühnast (MedUni Graz) and Marija Durdevic (MedUni Graz)

30 +5 min INVITED:"Three-dimensional insights into microbial ultrastructure" Ariane Briegel, University Leiden, The Netherlands

30 +5 min INVITED: BioTechMed-Graz Lecture:"Microbial interaction between humans and the built environment" Simon Lax, MIT, USA

8 +2 min

The International Space Station selects for microorganisms adapted to the extreme environment, but does not induce lasting genomic and

physiological changes relevant for human health Maximilian Mora, Austrian Centre of Industrial Biotechnology, Graz, Austria

8 +2 min Genome Sequences of Bacteriophages from Escherichia coli Friederike Hilbert, Inst of Food Safety, U. of Vet. Medicine, Vienna, Austria

8 +2 min

Impact of Medication, Nutrition and Probiotics in the First Three Weeks of Life: Comparison of Preterm Infants´ Gut Microbiomes in Three Neonatal

Intensive Care Units Charlotte Neumann, Medical University of Graz, Austria

10:40 11:15 Coffee break

Chairs: Barbara Klug (MedUni Graz) and Jakob Thannesberger (MedUni Wien)

25 +5 min INVITED:"Function of the intestinal microbiolty in health and disease" David Berry, University of Vienna, Austria

25 +5 min INVITED: "The transferable resistome" Kornelia Smalla, Julius Kühn Institute, Braunschweig, Germany

15 min PRESENTATION (short): MICROBIOME SUPPORT and INTIMIC projects Gabriele Berg (TU Graz), Peter Abuja (MU Graz)

12:30 14:30 Lunch break / poster pitches/ posters

Chairs: Wisnu Adi Wicaksono (TU Graz) and Elke Korb (MedUni Wien)

25 +5 min INVITED:"Immune-homeostasis and microbiome dynamics in lungs after birth and injury"

Dr. Sylvia Knapp, CeMM Research Center for Molecular Medicine of the Austrian

Academy of Sciences, Austria

30 +5 min INVITED:"Patho-physiology of bacterial vesiculation" Stefan Schild, University of Graz, Austria

15:35 16:00 Coffee break

Chairs: Bettina Halwachs-Wenzl (MedUni Graz) and Marcus Blohs (MedUni Graz)15 +3 min Highlights der Mikrobiomforschung 2019 Christine Moissl-Eichinger, Medical University Graz

15 +3 min Therapeutische Beeinflussung des Mikrobioms Christoph Högenauer, Medical University Graz

15 +3 min Mikrobiomdiagnostik Gregor Gorkiewicz, Medical University Graz

15 +3 min Antibiotikaresistenzen im Mikrobiom Robert Krause, Medical University Graz

15 +3 min Die Darm-Gehirn-Achse Peter Holzer, Medical University Graz

For invited speakers: speaker's dinner

Day 2 Friday 29.11.2019

Start End Topic/Title Speaker

8:15 9:00 Registration and setup

Chairs: Daria Rybakova (TU Graz) and Adrian Wolfgang (TU Graz)

25 +5 min INVITED: "Binary signalling between bacteria through vesicles" Leo Eberl, University of Zurich, Switzerland

25 +5 min INVITED: "Can we define biologically meaningful bacterial populations?" Martin F. Polz, University of Vienna, Austria

8 +2 min Extracellular vesicles derived from the probiotic strain E. coli O83: A novel nano-scale tool for the management of the allergic diseases Irma Schabussova, Medical University Vienna, Austria

8 +2 min Virulome, resistome, stress mastering and metabolic capabilities of archaeal Metagenome Assembled Genomes from the human gut Alexander Mahnert, Medical University of Graz, Austria

10:10 11:00 Coffee break and posters

Chairs: Philipp Wurm (MedUni Graz) and Larissa Teuschler (Uni Graz)

25 +5 min INVITED: "The food microbiome and biosafety aspects" Lise Korsten, University of Pretoria, South Africa

25 +5 min INVITED: "Plants as hosts for human pathogens with focus on Salmonella " Adam Schikora, Julius Kühn institute, Braunschweig, Germany

8 +2 min A backup for the next generation - vertical transmission of microbiota in alpine plant seeds Birgit Wassermann, Institute of Env. Biotechn. ,TU Graz, Austria

8 +2 min Microbial volatiles - Deciphering the diversity of 1-alkene producers Matthias Schweitzer, Institute of Env. Biotechn. ,TU Graz, Austria

8 +2 min The plant-associated antibiotic resistome Christina A. Müller Bogotá, Institute of Env. Biotechn. ,TU Graz, Austria

12:20 13:00 Light lunch break

Chairs: Pascal Mülner (TU Graz) and Manuela Pausan (MedUni Graz)

25 +5 min INVITED: "Belowground microbiota and the health of trees" Jesus Mercado Blanco, Instituto de Agricultura Sostenible, Cordoba, Spain

25 +5 min INVITED: "Soil microbiota and the health of vegetables"

Rita Grosch, Leibniz-Institute of Vegetable and Ornamental Crops, Großbeeren/Berlin,

Germany

10 min Poster awards and talk award , closing remarks, end of the symposium, sparkling wine reception and goodbye!

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14:30

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15:35

Session 6b: Plant microbiome

Program

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10:40

11:15

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12:30

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10:10

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Session 1: Microbiology

Session 2: Microbial functions

Session 4: Public lectures (in German)

Session 5: Vesicles and beyond

Session 6a: Plant microbiome

Session 3: Immune response and bacterial vesicle physiology

ABSTRACTS | CONTRIBUTED TALKS Session 1: Microbiology Thursday 28.11.2019, 9:00-10:40

The International Space Station selects for microorganisms adapted to the extreme environment, but does not induce lasting genomic and physiological changes relevant for human health Maximilian Mora1,2, Lisa Wink1, Ines Kögler1, Alexander Mahnert1, Petra Rettberg3, Petra Schwendner4, René Demets5, Charles Cockell4, Tatiana Alekhova6, Andreas Klingl7, Robert Krause1,8, Anna Zolotariof4, Alina Alexandrova6 & Christine Moissl-Eichinger1,8 1 Medical University of Graz, Austria.

2 Austrian Centre of Industrial Biotechnology, Graz, Austria

3 German Aerospace

Center (DLR), Institute of Aerospace Medicine, Radiation Biology Department, Cologne, Germany. 4 University of

Edinburgh, School of Physics and Astronomy, Edinburgh, UK. 5 European Space Research and Technology Centre (ESTEC),

Noordwijk, The Netherlands. 6 Lomonosov Moscow State University, Biological Faculty, Moscow, Russia.

7 Ludwig

Maximilians University of Munich, Plant Development and Electron Microscopy, Planegg-Martinsried, Germany. 8

BioTechMed-Graz, Austria

The International Space Station (ISS) is a unique, completely confined habitat for the human crew and co-inhabiting microorganisms. Here, we report on the results of the ISS experiment EXTREMOPHILES as recently published. We aimed to exploit the microbial information obtained from three sampling events aboard the ISS during increments 51 and 52 (2017) with respect to: i) microbial sources, diversity and distribution within the ISS, ii) functional capacity of microbiome and microbial isolates, iii) extremotolerance and antibiotics-resistance, and iv) microbial behavior towards ISS-relevant materials. We used wipe samples and analyzed them by amplicon and metagenomics sequencing, cultivation, comparative physiological studies, antibiotic resistance tests, genome analysis of isolates and co-incubation experiments with ISS-relevant materials. The major findings were: i) the ISS microbiome profile is highly similar to ground-based confined indoor environments, ii) the ISS microbiome is subject to fluctuations and indicative for the location , although a core microbiome was present over time and independent from location, iii) the ISS selects for microorganisms adapted to the extreme environment, but does not necessarily induce genomic and physiological changes iv) cleanrooms and cargo seems to be a minor source of microbial contamination aboard, and v) microorganisms can attach to and grow on ISS-relevant materials. Biofilm formation might be a threat for spacecraft materials integrity. We conclude that our data do not raise direct reason for concern with respect to crew health, but indicate a potential threat towards biofilm formation and material integrity in moist areas.

Genome Sequences of Bacteriophages from Escherichia coli Cátia Pacífico1,2, Miriam Hilbert2, Dmitrij Sofka1, Christoph Aspöck2,3, Ildiko-Julia Pap3, Friederike Hilbert1* 1Institute of Food Safety, University of Veterinary Medicine, Vienna, Austria,

2Karl Landsteiner University of Health

Sciences, Krems an der Donau, Austria, 3Institute of Hygiene and Microbiology, University Clinic St. Pölten, St. Pölten,

Austria Funded in part by NFB grant number LS14-006

Escherichia coli is the main cause of bloodstream infections in Europe and the Asia-Pacific region. Despite it is controversially discussed to what extent E. coli from food of animal origin contributes to human bloodstream infections, these microorganisms may enter the human host via food and may pass to the intestinal tract. Furthermore they can find their way to the urinary tract and may finally cause bloodstream infections. Recent studies show that not only bacteriophage associate with bacterial pathogens at infection sites, but the phage-bacterial interaction is relevant for virulence, intensity of disease and possible bacterial clearance. Here we describe coliphages isolated from food of animal origin, human blood and urinary tract infections/colonisation using whole genome sequencing. Phages isolated, belong to Siphoviridae, Myoviridae. Podoviridae and may harbour foreign DNA including virulence genes and antimicrobial resistance genes.

Impact of Medication, Nutrition and Probiotics in the First Three Weeks of Life: Comparison of Preterm Infants´ Gut Microbiomes in Three Neonatal Intensive Care Units Charlotte Neumann, Stefan Kurath-Koller, Berndt Urlesberger, Christine Moissl-Eichinger Medical University of Graz, Graz, Austria

The first weeks in life are crucial for the development of the infant´s microbiome. For research on necrotizing enterocolitis (NEC), the microbiome development is of great interest, as no specific cause of this disease has been identified yet and its anamnesis is most likely linked to a microbial component. For preterm-born infants spending their first days in hospital, factors shaping their microbiome are mainly the neonatal intensive care unit´s environment including parents’ microbiome, nutrition and medication. Therefore, the influence of these factors was compared in a cohort of 56 infants born in three Austrian hospitals which follow different NEC prophylaxis regimes regarding medication, probiotic administration and nutrition (details available at: Kurath-Koller et al., 2017):

Hospital A B C Probiotics Lactobacillus Bifidobacterium,

Lactobacillus None

Antibiotics Gentamycin None Gentamycin

Antimycotics Nystatin Fluconazole Nystatin

Feeding Mainly breastmilk Mainly formula milk Mainly breastmilk

The development of the infants’ gut microbiome during the first three weeks of life was investigated by 16S rRNA gene amplicon sequencing in overall 388 samples. Our results indicate, that the microbiomes are more similar in the first days but diverge with increasing age, shaping three significantly distinguishable clusters respective of the three hospitals. Even after correction for the differences in the probiotic regime, the microbiome profiles remained indicative for the hospital. This study shows that the hospitals´ regimes have major impact on the formation of the neonatal gut microbiome. For a better understanding of the anamnesis of NEC in this consideration, further investigations on these aspects need to be performed. Session 5: Vesicles and beyond Friday 29.11.2019, 9:00-10:10

Extracellular vesicles derived from the probiotic strain E. coli O83: A novel nano-scale tool for the management of the allergic diseases Schmid A., Zwicker C., Korb E., Kohl P., Schild S., Wiedermann U., Schabussova I. Medical University Vienna, Vienna, Austria

E. coli A0 34/86 (serotype O83:K24:H31; E. coli O83) is a probiotic bacterial strain that is commercially available as an oral live vaccine and used to treat nosocomial infections and diarrhea in infants. We have shown that intranasal application of E. coli O83 suppressed ovalbumin (OVA)-induced allergic airway inflammation in mice in a prophylactic and therapeutic setting, but the microbial factors that mediate these effects remain to be investigated. In this study, we isolated E. coli O83 outer membrane vesicles (EcO83-OMVs) by ultracentrifugation and tested them for their effect on the immune system in vitro and in vivo. EcO83-OMVs stimulated production of IL-8 in the human intestinal cell line HT-29. When co-cultured with splenocytes derived from naïve mice, EcO83-OMVs induced the secretion of IL-6, IL-10, TNF-? and IFN-? in a dose-dependent manner. Furthermore, we asked whether vesicles, similarly to the whole bacteria, have a beneficial effect on allergy. BALB/c mice were sensitized and challenged with OVA, and before each application, they received either 100 ng or 1 µg of EcO83-OMVs intranasally. EcO83-OMVs-treated mice exhibited reduced airway hyperreactivity, as measured by the whole-body plethysmography, and reduced airway eosinophilia compared to the controls. Thus we show that OMVs produced by probiotic bacteria communicate with and modulate the immune responses in the host. The exact mechanism of cellular uptake of OMVs and the activating signaling events in the host cells will be further investigated.

Virulome, resistome, stress mastering and metabolic capabilities of archaeal Metagenome Assembled Genomes from the human gut Alexander Mahnert, Alexandre Almeida, Cynthia Maria Chibani, Guillaume Borrel, Jean-Francois Brugere, Simonetta Gribaldo, Ruth Schmitz-Streit and Christine Moissl-Eichinger Diagnostic & Research Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria

Despite their central role at the end of the food chain and as a sink for bacterial metabolites, human gut-associated archaea are still neglected members of human microbiome research. However, constant improvements to analyze human metagenomes in a genome-centric way by binning MAGs (Metagenome Assembled Genomes) into high quality draft genomes helped us to deepen our understanding of the human microbiome and its archaeome. A meta-analysis of all available MAGs (286,997) revealed a fraction of 1,162 archaeal MAGs from the human gut. These archaeal MAGs were de-replicated with dRep using 90% ANI (Average Nucleotide Identity) for the primary clustering and 99% (refers to strain level) as well as 95% ANI (refers to species level) for the secondary clustering. The resulting subsets (28 and 81 archaeal MAGs at 95 and 99% respectively) were then processed with Magnifying Genomes (MaGe) to analyze the synteny of archaeal virulence and resistance genes as well as potentially reduced genome structures. Preliminary results showed 20 gene families and 3643 genes that belong to the archaeal core in the human gut. Four species also contained antimicrobial resistances like MacB an ATP-binding cassette (ABC) transporter that exports macrolides. In addition, virulence factors could be detected that covered functions involved in iron availability (ecfA, yecC) and prevention of phagocytosis (pseB). This new blueprint of archaea in the human gut will help us to better understand necessary adaptations of the human archaeome to its host as well as potential involvements in human disease and well-being. Session 6a: Plant microbiome Friday 29.11.2019, 11:00-12:20

A backup for the next generation - vertical transmission of microbiota in alpine plant seeds Birgit Wassermann, Henry Müller, Gabriele Berg Institute of Environmental Biotechnology, Graz University of Technology, Graz, Austria

Recent studies on crop plants provided first insights into the structure of seed microbiomes, and indicated significant impact on germination and plant performance. For native plants, complementary mechanisms are almost completely unknown. We studied the seeds of eight native plant species growing together for centuries under the same environmental conditions in Alpine meadows (Austria) by amplicon sequencing and qPCR targeting bacteria, archaea and fungi. Bacteria and fungi were determined with approx. 1010 gene copy numbers g-1 seed as abundant inhabitants. Archaea, which were newly discovered as seed endophytes, are less and represent only 1.1% of the signatures. The seed microbiome was highly diversified and all seeds showed a species-specific, highly unique microbial signature, sharing an exceptionally small core microbiome. A network analysis revealed significant co-occurrence patterns for bacteria and archaea, contrasting with an independent fungal network that was dominated by mutual exclusions. Additionally, FISH-CLSM indicated efficient proliferation of seed endophytes during gnotobiotic germination experiments. These novel insights into the native seed microbiome contribute to a deeper understanding of seed microbial diversity and phytopathological processes for plant health, and beyond that for ecosystem plasticity and diversification within plant-specific microbiota.

Microbial volatiles - Deciphering the diversity of 1-alkene producers Matthias Schweitzer, Andrea Friedrich, Gabriele Berg, Christina A. Müller Bogotá Institute of Environmental Biotechnology, Graz University of Technology, Graz, Austria

Volatiles are essential constituents of the plant microbiome and play an important role in inter- and intra-species communication. 1-Alkanes like 1-undecene are volatile organic compounds showing antimicrobial and antagonistic activity in plant-associated microbes such as Pseudomonas sp. Synthesis of 1-alkenes is often mediated by enzymes like the non-heme iron oxidases/decarboxylases UndA and UndB, which use medium-chain fatty acids as precursors. The pathways are highly conserved in three main genera: Burkholderia, Pseudomonas, and Myxococcus. Another important synthesis route is found in Jeotgalicoccus sp. ATCC 8456, via the fatty acid decarboxylase OleTJE. However, there is still limited knowledge about the diversity of OleTJE, UndA and UndB homologue enzymes in other microorganisms, especially in bacteria. To gain a better insight into the 1-alkene microbial synthesis we sequenced the genome of Jeotgalicoccus sp. ATCC 8456, annotated it and employed the genomic information for data mining. Furthermore, other 1-alkene producers belonging to the genera of Pseudomonas sp. and Bacillus sp. were identified. Degenerated PCR-primers were designed binding to conserved regions of OleTJE, UndA and UndB. These primers allow PCR-based screening of genomes and metagenomic libraries to identify new enzymes for hydrocarbon synthesis. Additionally, we looked into the conditions leading to 1-alkene production in vivo. The production of certain 1-alkenes was successfully influenced by feeding fatty acids with a certain chain length as precursors for the reaction. Our findings advance the current understanding of the microbial production of 1-alkenes and shed light onto the largely unexplored diversity of microbial biosynthetic routes.

The plant-associated antibiotic resistome Melanie-Maria Obermeier, Julian Taffner, Alessandro Bergna, Tomislav Cernava, Gabriele Berg, Christina Andrea Müller Bogotá Graz University of Technology, Graz, Austria

The global and continuously growing spread of antibiotic resistances urges a deeper understanding of the origin and evolution of resistance genes. Evidence suggests that natural evolution of environmental microbes is strongly linked to resistance development. However, our knowledge of the incidence of antibiotic resistances in pristine environments is still very limited; in particular, the plant resistome in undisturbed ecosystems has not been investigated yet. Employing a holistic screening approach, we extended our study of the intrinsic antibiotic resistome of plants from bog ecosystems to different geographic locations. In silico data mining revealed an exceptionally diverse pool of resistance determinants targeting 21 different drug classes, including natural and surprisingly also synthetic antibiotics. Abundant genes were associated to resistance against β-lactams and glycopeptide antibiotics. The screening of a culture collection led to identification of several multi-resistant bacterial isolates. More than 50% of the tested isolates showed resistance against sulfadiazine and vancomycin, independent of the geographic location. Multi-resistant strains were mainly affiliated to the genera Rouxiella, Serratia, Paraburkholderia and Pseudomonas. Through functional metagenomics a new class A β-lactamase was isolated and characterized, giving evidence for the presence of novel resistance genes in the native plant resistome. Our findings shed light onto the antibiotic resistance background of non-agricultural plants and highlight the ecological link between natural and clinically significant resistomes. The implications of this investigation also pave the way to a deeper understanding of the prevalence and evolution of resistances in less disturbed environments like the bog ecosystem.

ABSTRACTS | POSTERS Poster group 1: Human microbiome

Poster 1 The HDHL-INTIMIC Knowledge Platform (KP) on Food, Diet, Intestinal Microbiomics and Human Health Peter M. Abuja*, Eva Untersmayr*, Rudolf Bauer*, Enikö Kallay*, Evelyne Mann-Selberherr*, Barbara Strasser*, Marijana Basic, Jildau Bouwman, Maria De Angelis, Andre Gessner, Bart J.F. Keijser, Martin Larsen, Matthias Laudes, Tobias Pischon, Estelle Pujos-Guillot, Itai Sharon, on behalf of the KP members MUG, D&R Institute of Pathology, Graz, Austria

The KP is a 2-year JPI HDHL INTIMIC co-funded project (started in October 2019) that brings together more than 50 partners from Europe and associated states. It aims at integrating present knowledge on intestinal microbiomics and supports the development of ESFRI (European Strategy Forum on Research Infrastructures) BMS RIs (Biomedical Sciences Research Infrastructures) that will foster studies with relevant information on nutrition, health and microbiome to increase the impact of microbiome research in human health. The overall aim of the knowledge platform is to foster studies on the microbiome, nutrition and health by assembling available information in the field of microbiome research in a comprehensive way including also other disciplines (e.g. food science, metabolomics, physiology, gastroenterology) relevant in the context of microbiome research. The objective is to make this information findable, accessible, interoperable and reusable (FAIR) for the scientific community and to link and provide in-depth information to various stakeholders. Pertinent information accessible to the general public will also be provided. Moreover, since the FAIR principle includes integration of methodologies and data, the KP will link to ongoing standardization and harmonization initiatives (e.g. pre-analytic treatment of microbiome samples for diagnostics) and to existing ESFRI BMS RIs. In this respect, the KP will serve as a communication, data and information exchange platform to integrate the still fragmented microbiome research community and to support the development of a European Research Infrastructure. *The Austrian consortium is financially supported by BMBWF/FFG.

Poster 2 Methane production in the human body and the question whether we should worry about it Blohs M., Högenauer C., Moissl-Eichinger C. Medical University Graz, Graz, Austria

It is estimated that the human body harbours at least as many microbial cells as human cells. With about 1014 microbes, the gut contains the vast majority of syntrophic bacteria, archaea, and fungi that provide metabolic capacities equivalent to the liver, supporting digestion and influencing our health and well-being. A special role in this complex ecosystem is taken by methanogenic archaea (methanogens) that are regarded as key-stone species in the gut. Their unique ability to consume bacterial fermentation products such as CO2, H2, formate, or trimethylamine to form methane is arguably of high importance for the digestion process and may even protect us from harmful metabolites. However, what is the consequence of methane production to our bodies and to the environment? Methane is a potent greenhouse gas that is constantly released from biotic and abiotic sources. With about 7.5 billion individuals the human-released methane was estimated to be 344 ± 255 Gg by 2017 and is suspected to increase about fourfold to 1221 ± 672 Gg by 2100. Even beyond the global scale, methane is shown to influence human physiology, especially by decreasing intestinal bowel movement. Further aspects of methane on our bodies and its potential role as gasotransmitter are controversial discussed. This poster informs about the current knowledge of human-produced methane on environment and especially its impact on human physiology. Furthermore, we will propose our project MiCoMO (Microbial Community in Methane Overproducers) that aims to unravel the microbial background of high methane production in parts of the population.

Poster 3 We are what we eat – How the gut plays a role in phytoestrogen metabolism Valentin Borzan, Christoph Haudum, Natascha Schweighofer, Sabrina Teschl, Julia Brunner, Barbara Obermayer-Pietsch Department of Internal Medicine, Division of Endocrinology and Diabetology/Medical University of Graz, Graz, Austria Introduction: Whenever we ingest plant-derived food, we also ingest plant-derived hormones (phytohormones). Among them, phytoestrogens - in particular isoflavones - have been investigated as a possible therapy option in several hormone related conditions, including breast cancer and postmenopausal symptoms. The isoflavone daidzein can be found in high quantities e.g. in soy beans and is further metabolized into equol, which has been shown to have antiandrogenic, anticancer and antiinflammatory properties. However, in Western developed populations, only 30 percent have a microbiome composition able to convert daidzein to equol. Aim: We therefore addressed the role of equol metabolism in polycystic ovary syndrome (PCOS), a hormonal and metabolic condition affecting up to 22 percent of women worldwide. Methods: We performed a soy-challenge test in our ProPCO Pilot study testing probiotic intervention in 30 women with PCOS by ingesting 2x200 ml of soy milk at the start and the end of a 12-week´s intervention. Urine samples were collected thereafter to measure equol and daidzein concentrations. Results: During the current interim analysis, isoflavone concentrations in 15 participants have been measured. Of those, only 2 showed significant equol production. Of note, there was one “converter” from non-producer to equol-producer after 12 weeks of probiotic intervention. Discussion: We confirmed that equol production is rare in PCOS women. We aim to conduct a larger randomized controlled trial to test induction of equol production in PCOS women via probiotics.

Poster 4 The effects of fecal fermentation on the genotoxic properties of a complex extract of Alternaria mycotoxins Francesco Crudo, Georg Aichinger, Jovana Mihajlovic, Chiara Dall’Asta, David Berry, Doris Marko Department of Food and Drug, University of Parma, Italy Black molds of the genus Alternaria are ubiquitous fungi that can infect various fruits and vegetables and produce a cocktail of mycotoxins, some of which may pose a threat for human and animal health due to their genotoxic properties. Interactions might occur between mycotoxins, gut microbiota and dietary compounds, which may affect the bioavailability and therefore the global toxicity of the mycotoxins. Thus, the present work proposes to investigate the genotoxic effects of a chemically characterized extract of Alternaria mycotoxins on the human colorectal adenocarcinoma HT-29 cell line after in vitro short-time fecal fermentations. In particular, the involvement of the different fractions of human fecal samples (microorganisms, undigested food constituents and soluble substances) in modifying the overall genotoxicity of the extract was investigated through the application of the single cell gel electrophoresis (comet assay) and LC-MS/MS analysis. Results from the comet assay clearly showed that potential of the mycotoxins to induce DNA strand breaks was almost completely quenched, even before the fermentation, by contact with the different fractions of the fecal samples (including microorganisms), while oxidative DNA damages were only slightly reduced. These effects were found to be a consequence of the parallel reduction of mycotoxin concentrations found in the samples analyzed by LC-MS. Although a direct correlation between the metabolic activity of the gut microbiota and the modifications in mycotoxin contents was not clearly observed, adsorptive phenomena to the bacteria cells and to the undigested food constituents might explain the observed modifications, which therefore need to be further assessed.

Poster 5 Assembled genomes with MAGO tool from the shotgun sequences of fecal samples from the PlanHab project Leon Deutsch1, Boštjan Murovec 1, Robert Šket7, Tadej Debevec8, Blaž Stres1,3,4,5,6* 1 University of Ljubljana, Biotechnical Faculty, Ljubljana, Slovenia

2 University of Ljubljana, Faculty of Electrical

Engineering, Ljubljana, Slovenia 3 University of Ljubljana, Faculty of Medicine, Ljubljana, Slovenia

4 University of

Ljubljana, Faculty of Civil and Geodetic Engineering, Ljubljana, Slovenia 5 Jozef Štefan Institute, Ljubljana, Slovenia

6

Institute of Microbiology, University of Innsbruck, Innsbruck, Austria 7 Unit of Special Laboratory Diagnostics, Division of

Paediatrics, University Medical Centre Ljubljana, Ljubljana, Slovenia 8 University of Ljubljana, Faculty of Sport, Ljubljana,

Slovenia

We studied the dynamics and the diversity of the gut microbiome in response to reduced physical activity within the EU FP7 PlanHab project experiments. Our new open-source-software package Metagenome-Assembled Genomes Orchestra (MAGO; Murovec et al., (under revision)) was used for metagenome assembly, binning, bin improvement, bin quality control and bin annotation of reads obtained with shotgun seguencing (Ilumina Inc., USA ) from the fecal samples of the participants from the PlanHab study (MG-RAST #mgp17406 (Šket et al., 2018)). MAGO enables quality control and processing with FastQC and fastp and then makes use the three most popular assemblers (metaSPAdes, megaHIT, idba-ud) and six binners (MaxBin, MetaBat, CONCOCT, BinSanity, BinSanity-wf, BinSanity-lc). The resulting bins are improved by DAS tool and checked with CheckM (percentage of completeness and contamination). MAGO also enables building maximum likelihood protein trees with ezTree, prokaryotic genome annotation with Prokka, pan- and core-genome analysis with Roary and average nucleotide identity with FastANI. According to Tetra Correlation Score (TCS) on JSpeciesWS (Richter et al., 2015) we assembled 21 different strains of Streptococcus thermophilus, 8 different strains of Haemophilus parainfluanze, 3 different strains of Eubacterium siraeum, Phascolarctobacterium succinatutens and Ruminococcus bicirculans, Eubacterium eligens, next to 4 different strains of Eubacterium rectale. All newly assembled genomes assembled so far in this study (n=40) were classified as part of the human gut microbiota. This study shows the power of MAGO for reconstruction of metagenome-assembled genomes from raw sequence data and represents the first case of direct reconstruction from microbial metagenomes of Slovenian participants.

Poster 6 The role of gut microbiota in the response of glutathione to caloric restriction Duszka Kalina, Gregor Andras, Pignitter Marc, Somoza Veronika, König Jürgen Department of Nutritional Sciences, University of Vienna, Vienna, Austria The intestine is a key organ for energy and micronutrient absorption as well as for interactions of the whole organism with microbes. Recently activity of one of the most important non-enzyme antioxidants, glutathione (GSH) has been linked with microbial metabolites. To investigate the role of GSH in the intestinal response to dietary changes we submitted mice to caloric restriction (CR). The diet resulted in substantial gene expression changes in the intestinal epithelium affecting mRNA levels of inflammatory, metabolic and a set of glutathione S-transferases (GST) genes. The regulation was accompanied by an increased GST activity and decreased GSH concertation in CR compared to ad libitum fed mice. CR did not modify the activity of Nrf2 and GSH peroxidase but increases the activity of GSH reductase indicating that the synthesis of GSH is not affected but the balance between reduced and oxidized GSH is disturbed. Moreover, CR did not alter oxidative status or the levels of oxidized GSH in the intestinal epithelium suggesting an alternative role of GSH. Changes in the expression and activity of GST imply that elimination of metabolites via conjugation becomes a primary function of GSH in CR mice. Simultaneously, CR initiated microbiome composition changes. Therefore, we asked if gut bacteria play a significant role in the observed GSH regulation. Depletion of gut microbiota diminished the GSH-related phenotype and fecal transplant from CR animals triggered changes in GST gene expression. We propose that microbiota partly modulates the response of GSH to CR.

Poster 7 Surface layer proteins of lactobacilli M. Eder, A. Dordic, D. Vejzovic, T. Sagmeister, E. Damisch, L. Gambelli, F. Berni, J. Codee, J. Vonck, B. Daum, U. Hynönen and T. Pavkov-Keller Institute of Molecular Biosciences, University of Graz, Austria

Surface layers (S-layers) are 2D paracrystalline lattices of proteins or glycoproteins which cover the whole cell surface of many Archaea and Bacteria. Since these proteins are in close contact with the environment they fulfil many tasks like bacterial adherence to other cells or substrates, protection against life-threatening conditions and maintenance of the cell shape. S-layer proteins of lactobacilli species have a highly basic pI and are between 25-71 kDa. They are attached to the cell wall by interaction with lipoteichoic acids. It is reported that they are involved in auto- coaggregation and adherence and therefore are significant for the stimulation of gut dendritic cells. Our goal is to characterize the surface layer proteins SlpA of Lactobacillus acidophilus and Lactobacillus amylovorus. Both species are of enormous biological and medical relevance in consequence to their probiotic properties. We designed and produced several soluble fragments as well as full-length protein assembling into 2D-crystals. To elucidate the structure of the complete S-layer we apply an integrative structural biology approach combining X-ray crystallography, NMR, mass spectrometry and electron microscopy. The single domains of the S-Layer are characterized by X-ray and NMR while we aim to determine the structure of the assembled S-Layer by mass spectrometry and cryo-EM. To characterize the binding of S-layer proteins to the bacterial cell wall we performed isothermal titration calorimetry measurements. The obtained results allow us to learn more about the self-assembly formation, cell wall binding as well as broaden our knowledge about the role of these proteins in probiotic effects.

Poster 8 The Role of the Gut Microbiome in Cancer-induced Cachexia Daniela Fulterer1, Martina Schweiger2, Christine Moissl-Eichinger1 1 Medical University Graz, Austria

2 University of Graz, Austria

Introduction Changes in the gut microbiome correlate with the development of multiple (chronic) diseases, including cancer-induced cachexia (CAC). Hence, they hold a potential of being a therapeutic target. Previous studies found that common microbial signatures are associated with CAC. In addition, a symbiotic approach was found to prolong the overall survival in mouse models. (1) This study aims to compare changes in the gut microbiome in relation to CAC in three independent mouse cohorts, as well as a collective of patients diagnosed with colorectal cancer. Methods Mice were inoculated with cachexigenic (CHX) or non-cachexigenic (MCA) cancer cells. Tumor growth and body weight was monitored throughout the study. At different time points during the progression of cachexia, fecal samples were taken. Extracted DNA from human and murine fecal samples was subjected to PCR and phylogenetically characterized by 16SrRNA sequencing. To analyze the microbial community composition and taxonomic diversity the obtained raw reads were processed through a Galaxy (Hillman-Jackson et al., 2012) pipeline, using QIIME2. To calculate alpha and beta diversities, differences in community composition, and visualize the results, we applied Calypso (Zakrzewski et al., 2017). Results Compared to non-cachectic controls, cachectic mice from two independent cohorts showed a significant increase of Lactobacillus spp.. Additionally, we observed that this increase correlates with the severity and timeframe of the cachexia. 1. Bindels LB, Neyrinck AM, Claus SP, Le Roy CI, Grangette C, Pot B, et al. Synbiotic approach restores intestinal homeostasis and prolongs survival in leukaemic mice with cachexia. ISME J. 2016;

Poster 9 Human Milk Oligosaccharides modulate the risk for preterm birth in a microbiome dependent and independent manner Elisabeth Giselbrecht, Manuela-Raluca Pausan, Vassiliki Kolovetsiou-Kreiner, Gesa Lucia Richter, Tobias Madl, Eva-Christine Weiss, Evelyn Jantscher-Krenn and Christine Moissl-Eichinger Dept. Obstetrics and Gynecology, Medical University of Graz, Graz, Austria

Background: Preterm birth (PTB) is a leading cause of neonatal mortality. The causes for spontaneous PTB are multifactorial and remain often unknown. In this study, we tested the hypothesis that human milk oligosaccharides (HMOs), prebiotic, anti-infective and immunomodulatory glycans in maternal blood and urine, modulate the microbiome and influence the risk for PTB. We analyzed HMOs in urine and blood in women with and without preterm labor and correlated our findings with the vaginal and urinary microbiome. Methods: We recruited 60 pregnant women (23-34 weeks of gestation) hospitalized with suspected preterm contractions, and grouped them into cases with confirmed labor (n=33) and controls (n=27). We analyzed vaginal and urinary microbiome using next generation sequencing and quantified HMOs in serum and urine using HPLC. We further investigated correlations between HMOs and microbial composition. Results: We observed differences in serum HMO concentrations within the analyzed groups (short vs. normal cervix, tocolysis vs. no tocolysis, and PTB vs. term birth). Additionally, we found associations between sialylated HMOs with PTB, short cervix and inflammation. Specific HMOs, such as 2’-fucosyllactose and lactodifucotetraose positively correlated with members of microbial communities in vagina and urine confirming an influence of HMOs on the microbiome. Conclusion: Identifying HMOs and key microorganisms associated with PTB, our findings point at two processes modulating the risk for PTB. One process seems to be driven by sterile inflammation, characterized by increased concentrations of sialylated HMOs in serum. Another process might be microbiome-mediated, potentially driven by fucosylated HMOs in urine.

Poster 10 Effect of Helicobacter pylori on the NKG2D system Rosa Haller, Margit Neger, Iris Kufferath, Gregor Gorkiewicz Pathology/Medical University of Graz, Graz, Austria

NKG2D system is a stress- and tumour surveillance system. Under conditions of stress, like infection or tumour transformation, epithelial cells express ligands to the receptor NKG2D, which is expressed by NK and T cells. Binding of the receptor to the ligand triggers degradation of the ligand expressing cell. The system was mostly observed at epithelia in direct contact to the microbiota and along the gastro-intestinal tract it appears to be mostly expressed in the stomach. The bacterium H. pylori colonizes the gastric epithelium. About 50% of world’s population are infected, thus it is one of the most common infections worldwide. H. pylori is a major risk factor for gastritis, ulcers and gastric malignancies. However, it is also associated with protection from immunological disorders like asthma. This may be explained by H. pylori’s effect on the immune system. The infection causes a strong immune response, but the NKG2D system is downregulated, and the immune system is not able to clear the infection. We hypothesize, that H. pylori can suppress the NKG2D system and thus enables chronic infections. The bacterium might stimulate the release of soluble ligands via the activation of human proteases at the cell surface or via increased release of the ligands on extracellular vesicles. These soluble ligands are known to repress NKG2D. We aim to analyse 2 gastric epithelial cell lines for their expression of the highly polymorphic NKG2D ligands MICA and MICB and their presence in extracellular vesicles and cell culture media in reaction to H. pylori infection

Poster 11 Fecal microbial transplantation – A beneficial treatment modality for acute, refractory gastrointestinal graft-versus-host-disease Bettina Halwachs, Walter Spindelboeck, Peter Neumeister, Christoph Hoegenauer, Gregor Gorkiewicz Medical University of Graz, Graz, Austria

Acute graft-versus-host disease (aGvHD) is a serious complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Especially involvement of the lower gastrointestinal (GI) tract is complicated by high mortality rates. GvHD is already known for the tremendous loss of the intestinal bacterial diversity, which is also accompanied by acute diarrhea. This and the refractoriness to anti-GvHD therapies result in a poor prognosis of patients and limited therapeutic options. Recent data suggest that alterations of microbiota metabolites may affect GvHD target tissues beneficial. Hence, repeated fecal microbial transplantation (FMT), which aims in transferring normal fecal microorganisms into dysbiotic GI tracts, might be a beneficial treatment modality. At the example of two independent patients, representing severe cases of refractory GI-aGvHD following allo-HSCT, we describe the effect of repeated FMT on their highly dysbiotic stool microbiota. Finally, our preliminary available case data imply, that altering the intestinal microbiota by FMT should be considered as an attractive novel treatment approach for patients with refractory GI-aGvHD.

Poster 12 Antibacterial Effect of Lactobacillus casei rhamnosus (LCR 35) supernatant on Helicobacter pylori Zobia Hameed and Christine Moissl-Eichinger Medical University of Graz, Austria

Helicobacter pylori is a Gram-negative, spiral-shaped, microaerophilic pathogen that colonizes the mucus layer of human gastric epithelium. H. pylori is the major causative factor for peptic ulcer, gastric adenocarcinoma, and chronic gastritis in humans. H. pylori eradication therapy is losing efficiency due to increasing microbial antibiotic resistance worldwide. Probiotics have been reported to have antimicrobial properties and are emerging as promising tool for the treatment against H. pylori. It has been reported that certain Lactobacillus strains can inhibit the growth of H. pylori in vitro. The aim of this research is to study the antagonistic activity of Lactobacillus casei rhamnosus LCR 35 against H. pylori. The results of our experiments are promising as LCR 35 supernatant drastically reduces cell viability of H. pylori immediately after exposure. This study is supported by Germania Pharmazeutika GmbH. Keywords: H. pylori, probiotics, LCR35, Lactobacillus, antagonistic activity

Poster 13 Allergen exposure leads to shifts in the gut microbiome Elke Korb1, Tatjana Svoboda2, Monika Ehling Schulz2, Buck T. Hanson3, Craig Herbold3, Alexander Loy3, Stefanie Widder4, Ursula Wiedermann1, Irma Schabussova1 1Institute of Specific Prophylaxis and Tropical Medicine, Medical University of Vienna, Vienna, Austria;

2Institute of

Microbiology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria; 3Department of

Microbiology and Ecosystem Science, Division of Microbial Ecology, University of Vienna, Vienna, Austria; 4Department

of Medicine I, Medical University of Vienna, Austria

Environmental factors, such as westernized diet or the use of antibiotics have an impact on the gut microbiome. Interacting via the so-called gut-lung axis, intestinal dysbiosis has been associated with increased risk to develop allergic lung disease. Here, we ask whether interventions targeting the lung influence the gut microbiome. We investigated the impact of ovalbumin (OVA)-induced allergic airway inflammation and orally-induced OVA-specific tolerance on the gut microbiome by Fourier transform infrared spectroscopy and Illumina MiSeq sequencing of 16S rRNA gene amplicons. Additionally, we analyzed the levels of serum metabolites by HILIC-MS. OVA-treatment led to a diversification of microbial fingerprints between the groups, with the most prominent difference between sham and tolerized groups. At the family level, exposure to OVA increased the relative abundances of Rikenellaceae which have been associated with allergy, while Lachnospiraceae were reduced compared to controls. At the genus level, tolerized, but not allergic mice exhibited increased abundance of Odoribacter, a known producer of butyrate. Furthermore, separation between groups was observed on the levels of serum metabolites, too. Levels of L-carnitine and its alkylated forms were comparable between tolerized mice and controls but markedly reduced in allergic mice, supporting previous findings that L-carnitine supplementation reduces the severity of asthma in humans. In this project, we showed that allergen exposure regardless of the immunological state (i.e. sensitized or tolerized) shapes the gut microbiome and influences the metabolism. Identification of bacterial strain associated with allergy or tolerization might lead to novel prevention/treatment strategies against allergy.

Poster 14 Humans (and microbes) on their way to Mars Torben Kühnast, Christine Moissl-Eichinger Medical University Graz, Austria

One of the next challenges for human spaceflight is the crewed mission to Mars. Billions of microorganisms accompany the crew: either indigenous (gut, respiratory tract, etc.) or on the inner surfaces of the spacecraft. Recent studies have shown that molecular virulence of pathogens seems to be altered (either beneficial or adverse for human health) under microgravity conditions. Moreover, due to the strict confinement of a spacecraft, constant exchange with environmental microbiomes is impossible. To date, the microbiome-borne risk for spacecraft crews’ health is unknown. This project aims to gather information from available literature and own meta-analyses, in order to provide risk-assessments and microbiome monitoring recommendations for space agencies. In the first steps, we investigated the microbiomes of different body parts capable to indicate severe changes in health and microbiome composition to define the body sites of interest for monitoring. Secondly, we are focusing on microbiome data from spacecraft, ground-based space simulation facilities and from similar environments to detect detrimental effects caused by conditions unique to space. Our study includes a critical assessment of the available methodology (next generation sequencing- and cultivation-based characterization of the microbiome). Aside of the human microbiome, the environment within a spacecraft contains distinct microbial communities on the surfaces, on accompanying plants or life support units, possibly influencing the human microbiome. All of these places require monitoring of the microbial diversity. Herein we determine the necessity and frequency of such monitoring events, during and preceding space travel.

Poster 15 The Cow in You! – Correlations between methane levels and methanogens in the gut. Christina Kumpitsch, Florian Fischmeister, Christine Moissl-Eichinger Medical University of Graz, Austria

Methanogenic archaea are important keystone species in the human gastro-intestinal tract (GIT). Methanogens, like Methanobrevibacter smithii representing the most predominant one in the GIT, are able to generate methane by utilizing hydrogen and small carbon compounds, such as carbon dioxide or acetate. Methane, which is mainly excreted by flatus, diffuses also into the systemic circulation and can thus be detected in breath. Levels of breath methane might be influenced by long-term diet, as this impacts the overall microbiome composition and thus also the abundance of methanogens. Methane was found to slower gut transit, by directly influencing gut motility. This study aims to show the correlation between increased abundance of methanogens and elevated methane levels in breath should be confirmed. Furthermore, the role of participant’s diet on gut microbiome and microbial produced methane emitted through breath as a consequence of altered microbial composition in the gut should be investigated. In this study, 15% of the participants (n= 100) were classified as high methane emitters (breath methane level ≥ 5ppm) via breath test. Relative (next generation sequencing) and absolute abundance (quantitative PCR) of methanogens was increased in high methane emitters compared to low emitters and we could confirm that Methanobrevibacter correlates significantly with elevated breath methane levels. Notably, Methanobacteriaceae were found to co-occur with Christensenellaceae, a heritable bacterial component of the human microbiome. Metagenomic and metabolomics analyses are currently being performed and results will be presented.

Poster 16 Helicobacter pylori inhibits NKG2D-mediated Immune Activity Margit Neger, Rosa Haller, Markus Windisch, Sebastian Wrighton, Ana Montalban-Arques, Philipp Wurm, Silvia Schauer, Mar Vales Gomez, Hugh T Reyburn, Gregor Gorkiewicz Institute of Pathology, Medical University of Graz, Graz, Austria

Background/Aims: Gastric carcinoma is the second leading cause of death of all malignancies worldwide. A major risk factor is the colonization of the stomach with the bacterium Helicobacter pylori, which causes carcinogenesis in 1-3% of infected persons. So far, it has not been completely clarified under what circumstances H. pylori causes cancer and which mechanisms are responsible. In this context we observed a down-regulation of the immune receptor NKG2D in H. pylori infected patients (Montalban-Arques et al., 2016). NKG2D is typically located on the surface of NK- and CD8+ T cells and operates the natural recognition and elimination of infected-, stressed- and tumor cells. We hypothesize, that H. pylori inhibits NKG2D in order to establish a tolerant immune environment that allows bacterial persistence, but also impairs tumor recognition and thus contributes to gastric carcinogenesis. Here we aim to elucidate by which mechanisms H. pylori mediates the inhibition of NKG2D in the gastric mucosa. Results: Immunohistochemical studies of gastric biopsies and in vitro infection assays revealed that H. pylori causes the expression and secretion of NKG2D-ligands in the infected gastric epithelium. Secreted NKG2D-Ligands are known to act as repressors of NKG2D-mediated immune activity and are often produced by tumors to escape immune recognition. Immune assays showed that NKG2D-Ligands, secreted from the H. pylori infected gastric epithelium, down regulate NKG2D expression on the surface of NK cells. Conclusion: In conclusion we show that H. pylori initiates an immune evasion strategy which might contribute to chronic infection and its sequels like stomach cancer.

Poster 17 Pregnancy-related changes in the microbiome Manuela-Raluca Pausan, Evelyn Jantscher-Krenn, Eva-Christine Weiss, Vassiliki Kolovetsiou-Kreiner, Christine Moissl-Eichinger Medical University of Graz, Graz, Austria

Numerous changes occur in the mother’s body during pregnancy, including the microbiota. The changes that take place in the vaginal and gut microbiota are important for the vertical transfer of microbes from mother to child. During birth, infants acquire most of the microorganisms from the mother and an early interaction with commensal microbiota is essential for the development of a healthy immune system. Therefore, studying and understanding the changes that occur in the mother’s microbiome during pregnancy are important, especially as the outcome of the pregnancy is strongly linked to the mother’s microbiome and these changes have an influence on the neonatal and infant health. The aim of our study is to explore the microbial changes that occur in pregnancy and shortly after giving birth at different body sites (i.e. vagina, gastrointestinal tract, oral cavity, and urinary tract) by comparing the microbiome of pregnant women with a control group. The microbiome (bacteria, archaea and fungi) from different body sites have been explored using a NGS approach based on amplicon sequencing. Preliminary results show that the microbiome is only partially different in pregnancy when compared to the microbiome of non-pregnant controls. Significant changes in alpha and beta diversity have been observed only in the vaginal and urinary microbiome, while changes in specific taxa have been detected in all body sites explored.

Poster 18 Skin and gut microbiota dysbiosis in patients with moderate-to-severe acne: Results of a case-control study Rainer B, Thompson K, Antonescu C, Florea L, Mongodin E, Kang S, Chien AL Department of Dermatology, Medical University of Graz, Graz, Austria

Associations between acne vulgaris and gastrointestinal comorbidities suggest that microbial dysbiosis and intestinal permeability may promote inflammatory acne, a condition often managed with oral antibiotics. We performed a case-control study to investigate the skin and gut microbiota in 8 patients with moderate-to-severe acne before and after receiving oral minocycline compared to controls matched by age, sex, and race. DNA was extracted from stool samples and bacterial swabs of the nose, cheeks, and chin. Sequencing of the V3V4 region of the bacterial 16S rRNA gene was performed using Illumina MiSeq and analyzed using QIIME/Phyloseq softwares. Shannon diversity was not found to be significantly different between the skin (p=0.153) or stool (p=1) microbiota of acne patients before and after antibiotics. The gut microbiota in pre-antibiotic acne patients compared to acne-free controls was depleted in probiotic species Lactobacillus iners (p=0.001), L. zeae (p=0.02), and Bifidobacterium animalis (p=0.026), while the skin microbiota was enriched in Prevotella nigrescens (p=0.008), P. melaninogenica (p=0.035), Rothia mucilaginosa (p=0.043), and R. aeria (p=0.047) and depleted in Coprococcus eutactus (p=0.049). After antibiotics, the gut microbiota of acne patients was depleted in L. salivarius (p=0.001), B. adolescentis (p=0.002), B. pseudolongum (p=0.010), and B. breve (p=0.042), while the skin microbiota was enriched in probiotics B. longum (p=0.028) and Leuconostoc mesenteroides (p=0.029) and depleted in Staphylococcus epidermidis (p=0.009) and P. nigrescens (p=0.028). At the phylum level, significant enrichment of Bacteroidetes in stool of acne patients following antibiotic treatment (p=0.033) led to a decreased Firmicutes to Bacteroidetes ratio. Minocycline produces significant derangements in the microbiota of both the skin and gut, including many probiotic species, highlighting the need for more targeted antimicrobial treatments for acne.

Poster 19 Outer membrane vesicles isolated from the probiotic strain E. coli 083 induce immune responses in mouse and human Schmid A, Súkeníková L, Zwicker C, Korb E, Kohl P, Schild S, Afonyushkin T, Hrdý J, Wiedermann U and Schabussova I Institute of specific prophylaxis and tropical medicine, Medical University of Vienna, Vienna, Austria

E. coli O83 is a probiotic bacterial strain that is commercially available as an oral live vaccine. We have shown that intranasal application of E. coli O83 suppressed ovalbumin (OVA)-induced allergic airway inflammation in mice, but the microbial factors that mediate these effects remain to be investigated. Outer membrane vesicles (OMVs) are secreted by Gram-negative bacteria and contain immunomodulatory compounds, while being non-replicative. Here we isolated OMVs from E. coli O83 (EcO83-OMVs) by ultracentrifugation and tested them for their effect on the immune system. In vivo, intranasal treatment with EcO83-OMVs, similarly to the whole bacteria, reduced airway hyperreactivity, airway eosinophilia and levels of OVA-specific IL-4, IL-5, and IL-13 in lung, spleen and bronchial lymph nodes compared to sham-treated mice. This effect was associated with fostering the OVA-specific response in the lung toward the counter regulating Th1 phenotype. In vitro, stimulation of splenocytes or bone marrow-derived dendritic cells derived from naïve BALB/c mice with EcO83-OMVs mirrored the phenotype observed in vivo. Additionally, increased levels of IL-10 were observed in these cultures. Stimulation of peripheral blood mononuclear cells (PBMCs) and monocyte-derived dendritic cells (moDCs) isolated from healthy donors with EcO83-OMVs increased gene expression of IL-10 and IFN-γ or IL-10 and IL-12, respectively. Induction of such cytokine combination by EcO83-OMVs might be a promising concept for future immunotherapy of type I allergy. Here we show that OMVs produced by probiotic bacteria are an effective strategy to communicate with and modulate immune responses in the host, leading to allergy prevention or treatment.

Poster 20 “BORN TO RUN“: Insights into human intestinal microbiota and metabolome dynamics of normoxic and hypoxic bedrest studies Robert Šket1, Tadej Debevec2,9, Nicole Treichel3, Susanne Kublik3, Anne Schoeller3, Michael Schloter3, Boštjan Murovec4, Katarina Vogel Mikuš5, Damjan Makuc6, Klemen Pečnik6, Janez Plavec6, Ola Eiken7, Igor Mekjavic2, Marius Vital8, Jenna Chandler8, James M. Tiedje8, Zala Prevoršek1, Blaž Stres1,10* 1 Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia;

2 Department of

Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia; 3 Research Unit for Comparative

Microbiome Analysis, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany;

4Machine Vision Laboratory, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia;

5University of Ljubljana, Biotechnical Faculty, Department of Biology, Ljubljana, Slovenia;

6Slovenian NMR Centre,

National Institute of Chemistry, Ljubljana, Slovenia; 7Department of Environmental Physiology, Swedish Aerospace

Physiology Centre, Royal Institute of Technology, Stockholm, Sweden; 8Michigan State University, Center for Microbial

Ecology, East Lansing, Michigan, USA; 9Faculty of Sport, University of Ljubljana, Ljubljana, Slovenia;

10Center for Clinical

Neurophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia

Separate and joint effects of physical inactivity, a reduction in gravity due to the horizontal immobilization (hydrostatic pressure) and the partial reduction of oxygen saturation (hypoxia) on the human intestinal microbiota and intestinal metabolites in healthy volunteers were investigated under medical supervision in controlled conditions for 21 days. Samples were obtained within EU PlanHab project (Planetary Habitat Simulation project EU FP7-space; http://www.planhab.com/; PI: Igor Mekjavić, IJS: Jozef Stefan Institute, Ljubljana). Stool samples were collected during run-in period (days -5 and -1 before the onset of experiments) and days 3, 10, 18 and 21 of the three experimental settings ((i) normoxic bedrest, (ii) hypoxic bedrest and (iii) hypoxic ambulatory). Deep sequencing using paired-end MiSeq approach was used for fine scale characterization and identification of key microbial groups and their functional role responding to

environmental perturbation. 1H-NMR was used for targeted metabolomics profiling. Existing human physiological data were compiled for the same days of experiments. The influence of food intake (quantity and nutrient composition) on microbial composition was also analyzed and used as control for comparison between baseline data collections and post experimental variants. Significant changes in physiology coincided with changes in intestinal environment but preceded or took place in absence of significant changes in bacterial community structure. Highly responsive Bacteroides with inflammagenic characteristics and genes involved in iron acquisition, cell wall, capsule, virulence and mucin degradation were enriched in physiologically most detrimental variant. The first hierarchical model linking initial body deconditioning and microbiome in response to the acute inactivity was derived.

Poster 21 A link between uncultured members of Ruminococcaceae and efficacy of FMT in ulcerative colitis Philipp Wurm1,2,3,4, Marija Durdevic1,5, Bettina Halwachs1,2,3,4, Barbara Jelusic1, Patrizia Kump2,3, Christoph Högenauer2,3,4, Gregor Gorkiewicz1,3,4 1Diagnostic and Research Institute of Pathology, Diagnostic and Research Center for Molecular BioMedicine, Medical

University of Graz, Graz, Austria. 2Division of Gastroenterology and Hepatology, Department of Internal Medicine,

Medical University of Graz, Austria. 3Theodor Escherich Laboratory for Medical Microbiome Research, Medical

University of Graz, Austria. 4BioTechMed-Graz, Austria. 5Center for Medical Research, Medical University of Graz,

Austria

Faecal microbiota transplantation (FMT) is a promising novel therapy for ulcerative colitis (UC). Nevertheless factors influencing efficacy and response of FMT in patients remain unclear. Thus, we performed an open controlled trial with repeated FMTs after antibiotic pre-treatment in therapy refractory chronic active UC over 90 days (FMT-group). A control group received only the antibiotic pre-treatment (AB-group). We could show a superiority of FMT subsequent to antibiotic treatment over sole antibiotic therapy shown by clinical response in 59% of patients within the FMT-group. We found that the taxonomic composition of the donor might be an important driver for clinical efficacy in patients. Increased bacterial richness together with high relative abundance of Akkermansia muciniphila, unclassified Ruminococcaceae, and Ruminococcus spp. were detected in donor stools inducing remission [1]. Using 16S rRNA gene amplicon sequencing from rectal biopsies, we could show that an increase of uncultivated genera within the family Ruminococcaceae in the patients' mucosal microbiota are associated with clinical remission due to FMT. We were also able to identify longitudinal changes in the mucosal microbiota following FMT treatment that vary from the luminal microbiota, providing new insights into microbial dynamics in therapy refractory UC receiving FMT. This study highlights the importance of certain Ruminococcaceae for FMT efficacy and their possible contribution to gastrointestinal health. [1]: Kump P, Wurm P, Gröchenig HP, et al. The taxonomic composition of the donor intestinal microbiota is a major factor influencing the efficacy of faecal microbiota transplantation in therapy refractory ulcerative colitis. Aliment Pharmacol Ther. 2018;47:67-77. https://doi.org/10.1111/apt.14387

Poster group 2: Plant and environmental microbiomes

Poster 22 Potato endophytic and epiphytic bacteria for development of microbial preparations for biological protection of new potato varieties Vladimir Chebotar, Alexander Zaplatkin, Oksana Komarova, Maria Baganova, Nikolai Polukhin Lab of Microbial Technology,All Russia Research Institute for Agricultural Microbiology, Saint-Petersburg, Russia

For potato breeding it is important to use effective and environmentally friendly microbial preparations that increase the productivity and resistance of plants to adverse environmental factors and diseases. Using the developed original methods, 120 isolates of endophytic and epiphytic bacteria were isolated from wild potato tubers and 74 from cultivated tubers. For further research were selected two strains of endophytic bacteria Paenibacillus xylanexedens N40 and Bacillus thuringiensis W65. Testing of new microbial preparations was carried out in small-scale field experiments using three varieties of potatoes of different maturity groups - Sambo (very early), Reggae (early), Tango (late).The biofungicide Bisolbisan was used as a standard. Treatment of potato plants with new microbial preparations contributed to the growth of a larger leaf area. The best effect is obtained on varieties of Tango and Reggae when used preparation based on P. xylanexedens N40 (an increase of 39 and 66%, respectively) and the cultivar Sambo when used preparation Bisolbisan (an increase of 52%).Significant yield increase of potato was obtained on the cultivar Tango from preparations Bisolbisun and strain N40, respectively 13.3 and 13.7 t/ha; on the cultivar Reggae from all preparations, the increase was 3.9-10.5 t/ha, the cultivar Sambo a significant increase was not observed. The greatest impact of the studied microbial preparations had on the cultivar Reggae, the average increase on this variety was 5,2 t/ ha, while on the Tango and Sambo cultivars respectively 2.2 and -0.86 t/ ha.

Poster 23 Influence of hydrolytic enzymes on methane production and microbial community in mesophilic semi-continuous anaerobic digestion of waste paper sludge Sabina Kolbl Repinc, Blaž Stres UL-FGG, Ljubljana, Slovenia

The primary aim of this study was to use secondary dehydrated paper pulp sludge from production of hygienic paper manufactured by Paloma d.d. in 60 day semi-continuous process of anaerobic digestion on 5 L laboratory scale in order to evaluate methane production and partly replace earth gas that is used in production of hygienic papers with biogas to reduce usage of earth gas that is needed in the making of paper products. Second optimization of methane production of paper pulp sludge was tested by addition of commercially available enzymes and microorganisms additives. After 45 days of semi-continuous process, pig slurry manure was introduced to all reactors to complement nitrogen requirements. Further dynamics in bacterial and archaea communities were monitored using 16S rRNA gene T-RFLP. Temperature of experiment was set to 37 ± 2 °C. Every fifth day the following parameters were monitored: pH, VS, TS and COD. Volatile organic acids (VOA), total inorganic carbon (TIC) and ratio VOA/TIC were measured with TIM 840 titrator (Hach Lange), total nitrogen and ammonium nitrogen with Skalar San++. Organic loading of anaerobic reactors was 2.2 g VS/l day and biomass from the biogas plant Šijanec was used as inoculum.

Poster 24 Hospital Microbiome and Resistome Kaisa Koskinen, Stefanie Duller, Alexander Mahnert, Christine Moissl-Eichinger Medical University of Graz, Graz, Austria

Hospital-acquired infections are a serious problem worldwide. The risk is not only related to invasive procedures or inadequate hygiene, but infection can also be transferred from patient to patient, via personnel, surfaces or equipment. Despite strict disinfection procedures resistant pathogenic bacteria are frequently found on hospital surfaces, and these microorganisms can influence the patient recovery and outcome. Hospital indoor environment carries also diverse microbial communities, consisting mainly of human associated bacteria, and interaction between these communities, pathogenic bacteria, and resistance elements is not well understood. The goal of this study is to deepen our understanding about the microbial community dynamics in hospital departments of different confinement level. Particularly, we aim to determine the interplay between confinement, microbial diversity and distribution and transfer of (antibiotic) resistance genes. We analysed the microbiome and resistome of different areas and locations at the pulmonology department, intensive care unit, and operating room at Medical University of Graz. Analysis of microbiome data showed significant differences in microbial community diversity and structure depending on confinement level, and a strong influence of human skin associated bacteria and potential pathogens was detected. The taxonomic and functional profiles in operating room surfaces, the cleanest and most confined location of the study, differed significantly from other areas. With this poster, I will present the latest results of the project.

Poster 25 Native prokaryotic communities in Karst: So much water underground but where are the microbes? Mojca Likar1, Janez Mulec2, Zala Prevoršek3, Robert Šket3, Metka Petrič2, Ladislav Holko4, Cene Gostinčar3, Leon Deutsch3, Blaž Stres1,3,5 1 University of Ljubljana, Faculty of Civil and Geodetic Engineering, Ljubljana, Slovenia

2 Karst Research Institute, SAZU,

Postojna, Slovenia 3 University of Ljubljana, Biotechnical Faculty, Ljubljana, Slovenia

4 Slovak Academy of Sciences,

institute of Hydrology, Slovakia 5 Jozef Stefan Institute, Ljubljana

About ninety-five percent of global liquid freshwater is stored in the terrestrial subsurface, making it the largest terrestrial freshwater biome. Despite the importance of this water source for humanity, these systems are largely understudied from the microbiological point of view. In Slovenia, about half of the population depends on groundwater for its domestic needs. The quality of this water source and the putative presence of pathogens are not properly monitored. Accordingly, very little is known about the composition and the structure of its native prokaryotic communities. We analyzed a time-series of 16 months of sampling from two pristine groundwater reservoirs. A number of physical and chemical parameters (n=21) were monitored and microbial cells were size fractionated into >5 um, >0.45 um and >0.1 um fractions. Large volumes (100 l / filter) were filtered to obtain measurable quantities of DNA for metagenomic sequencing. Here we present the basic environmental characteristics coupled to initial analysis of shotgun metagenomic data obtained from various size fractions of microbial communities and provide basis for massive assemblies of available cave shotgun sequencing to metagenome assembled genomes in the future.

Poster 26 Characterisation of indoor microbiome in newly built hospital Mantaj Polina, Duller Stefanie, Koskinen Kaisa, Moissl-Eichinger Christine Medical University of Graz, Graz, Austria

This poster details a study on the microbiome of a newly built surgical department building at the Hospital of the Medical University of Graz, Austria. To date, not much is known about the development of the indoor microbiome in hospitals, although the exposure to these microorganisms has an important impact on human health. Particularly in a hospital environment, where the range of microorganisms is constantly changing, surgical patients - prone to infection - are being treated and large numbers of people come and go, it is crucial to explore and describe the indoor microbiome and microbiota and how it affects human health and wellbeing. In this study samples from patient rooms of the Department of General Surgery were taken on six different time points over the period of one year. They were taken from different surfaces such as lights, floors under patients’ beds, medical workplace surfaces, bathroom sinks and frequently touched items such as pillows, water taps, door handles, remote controls and toilet flush buttons. After DNA extraction and amplification of the hypervariable region V4 of the 16S rRNA and Illumina MiSeq sequencing, the variety of microorganisms was identified and further analyzed. In this poster presentation, we will summarize the results of this project. These results could help understand the diversity of microorganisms living in hospital surroundings and their spread through the building, identifying the operational characteristics of buildings that influence these microbiotas, and change indoor ecosystems in a way to prevent the spread of nosocomial pathogens.

Poster 27 Soil-borne fungal pathogens and their natural antagonists – an odorous interaction Pascal Mülner, Dženana Sarajlić, Kristin Dietel, Tomislav Cernava and Gabriele Berg Institute of Environmental Biotechnology, TU Graz, Austria

Soil-borne pathogens such as Sclerotinia sclerotiorum and Rhizoctonia solani which are able to form persistent structures called sclerotia are particularly challenging to manage. In the last years, several broad-spectrum, as well as specific fungicides, were developed to control Rhizoctonia, but the negative effects of various chemicals on the ecological balance of soil-microorganisms, rising resistances, and groundwater pollution make them non-sustainable solutions for future crop protection. Therefore, there is a global need for a biological solution to avoid substantial yield losses. In order to control these plant diseases, it is essential to understand their interactions with natural antagonists. In consequence, the volatilomes of fungal pathogens and bacterial biocontrol agents were investigated. Phytopathogenic fungi and antagonistic bacteria produced a variety of volatile hydrocarbons, alcohols and ketones. Sulfur-containing compounds and pyrazines were restricted to the volatile profiles of Bacillus spp. and Pseudomonas sp. The stimulation of bacteria with fungal volatiles resulted in a formation of novel volatiles. Several responding compounds revealed antifungal and in some cases even antibacterial activity. Furthermore, sclerotia of S. sclerotiorum assemble more than 100 different non-volatile compounds. Under stressed conditions caused by bacterial volatiles, 37 substances were enhanced. Among these, antifungal and antibacterial compounds such as citrinin and 2,5-dimethylpyrazine are notably abundant. In general, stress responses to microbial volatiles seem to be non-target specific and result in a production of various antimicrobial compounds. These novel insights could help to understand the interactions of plants, pathogens and natural antagonists to improve the development of biological alternatives to potential hazardous fungicides.

Poster 28 Transcriptomic response of the endophytic, plant-growth promoting bacterium Stenotrophomonas rhizophila P69 to changing environmental conditions Manuel Reisinger, Henry Müller and Gabriele Berg Institute of Environmental Biotechnology, TU Graz, Austria

Plants are primarily inhabited by endophytic bacteria, which leads to the formation of relationships that can be symbiotic, commensalistic, mutualistic or trophobiotic each with its own set of effects and consequences for the host plant. The genus Stenotrophomonas harbours species capable of colonizing a wide array of habitats. S. rhizophila for example, is both rhizosphere- and phylloplane- competent and shows pronounced salt tolerance. Furthermore, it contains strains with biotechnological relevance as biocontrol, plant-growth promoting or stress protecting agents used in agricultural systems. It is therefore used as a model bacterium among the plant growth-promoting rhizobacteria. The objective of this study was to investigate and observe the transcriptomic response of the plant-associated strain Stenotrophomonas rhizophila P69 to changing environmental conditions. These conditions include variations in cultivation parameters such as nutrient availability, exposure to plant root exudates, osmotic stress, temperature and cultivation on liquid versus solid medium. Furthermore, co-cultivation with plant-beneficial fungus Trichoderma spp. and the fungal phytopathogen Verticillium spp. was carried out with supplementation of culture media with root exudates, harvested from maize and tomato plants, was shown to play a comparatively marginal role on the strain’s overall gene expression profile, with most differentially expressed genes associated with the metabolism and transport of amino acids, specifically histidine and glutamate. A shift from the casamino acids minimal salt medium to LB complex medium had a far more pronounced effect on gene expression. Overall, analysis of functional gene groups of differential expression profiles revealed significant differences in the regulation of metabolic pathways.

Poster 29 Structural characterization of altiarchaeal grappling hooks Hami from Candidatus Altiarchaeum hamiconexum Sagmeister T, Vejzoviz D, Moissl-Eichinger C and Pavkov-Keller T Institute of Molecular Biosciences, University of Graz, Graz, Austria

The most common cell envelope structure in Archaea is the Surface-layer (S-layer) on top of the cytoplasmic membrane, especially within extremophiles where the S-layer seems to be vital for surviving extreme conditions. The cell envelope of Candidatus Altiarcheaum hamiconexum, a biofilm forming archaea found in cold sulfidic springs shows something rather unusual for Archaea: it has no S-layer envelope, but instead consists out of an inner membrane, periplasm and an outer membrane similar to Gram-negative bacteria. Ca. A. hamiconexum expresses the Hamus (pl. Hami, lat. hook) protein, which has a N-terminal S-layer domain and assembles into long grappling hooks on top of the cell envelope. These cell appendices form several prickle regions and split at the end in a hook regions. Since today, no atomic structure of the Hamus protein is available and our aim is to obtain a high resolution structure with X-ray crystallography. To study the atomic structure the protein was expressed recombinantly and tested for solubility. Since the full length protein is insoluble we assessed this task with the “divide and conquer” approach - using sequence analysis tools to define the probable soluble domains. In this process we cloned and expressed over 30 different fragments of the Hamus protein to further characterizes them.

Poster 30 Biological control of potato diseases guided by plant microbiome approaches Franz Stocker, Tomislav Cernava, Gabriele Berg Institute of Environmental Biotechnology, TU Graz, Austria

Plant protection against fungal pathogens is a crucial aspect of modern agriculture and mostly relies on chemical inputs. However, phytopathogens often become resistant against conventional fungicides. Additionally, the microbial diversity in agricultural soils decreases through the application of pesticides, fertilizers and the soil tillage. The aim of the ongoing SusCrop – ERA-NET project ‘PotatoMETAbiome’ is to establish microbial consortia, which are applicable for potato cultivation to mediate the resistance against soil-borne fungal pathogens (Verticillium dahliae and Rhizoctonia solani) and support the microbial diversity in soil. For the consortium assembly, pre-selected microorganisms from the strain collection for antagonistic microorganisms SCAM (Institute of Environmental Biotechnology, Graz University of Technology) will be implemented. A total of 111 bacterial strains were already tested comprising the genera Bacillus, Erwinia, Paenibacillus, Pseudomonas, Serratia, Streptomyces, Ralstonia and several yet unidentified species. Additionally, fungi of the genus Trichoderma were assessed in terms of antagonistic effects. They will be optimized in vitro in terms of their efficiency to inhibit the target phytopathogens. The best antagonistic microorganisms will be used for consortium assemblies and their VOCs profiles will be assessed. Established consortia will then be combined with root exudates, which can act as a ‘boosters’ for the microorganisms. Furthermore, the consortia will be applied in greenhouse experiments and field trials. In a final step, meta-transcriptomic datasets will be obtained to analyze the interaction of the microorganisms in the consortium.

Poster 31 Plant-associated archaea: colonization, vertical transmission, and interactions Julian Taffner, Alessandro Bergna, Tomislav Cernava, Birgit Wassermann, Christine Moissl-Eichinger, Gabriele Berg Institute of Environmental Biotechnology, TU Graz, Austria

Plant holobionts are known to harbour a wide diversity of microorganisms, such as bacteria and fungi, influencing plant nutrition, resistance to stress and fitness. Though, recent studies identified archaea as substantial members of plant microbiomes, but their transmission, functions and interactions with their hosts remained mostly unclear. To get a deeper insight into the community structure, habitat preferences, vertical transmission, and functions of plant-associated archaea, we compared 42 different agriculturally used plant-species from the Mediterranean area, Austria and Eastern Africa as well as the vegetation of alpine raised bogs. Therefore we used a combined approach including real-time PCR (qPCR), 16S rRNA amplicon sequencing, whole metagenome shotgun sequencing and fluorescence in situ hybridization confocal laser scanning microscopy (FISH-CLSM). The abundance of archaea varied for each plant genotype, whereat enrichment in the rhizosphere was detected. In agricultural used plants without supplementation of additional fertilizers the archaeal community structure was clearly dominated by Thaumarchaeota, whereas in bog vegetation and on fertilized fields Euryarchaeota were predominant. Although archaea showed abundances up to 109 copies g-1 in seeds of tomatoes or alpine plants, no indications of a plant-mediated vertical transmission of archaea were found. This indicates that archaea represent only bystander microorganisms in seeds. On plants, we observed signatures for putative adaptation mechanisms of archaea for their hosts, including those for higher chemotaxis, nutrient cycling like CO2 fixation, stress response, especially against oxidative stress, and possible plant growth promotion through auxin. These findings reveal a so far unobserved role of archaea for plant holobionts.

Poster 32 Novel CRESS virus identified as member of Aedes aegypti virome Thannesberger J, Rascovan N, Klymiuk I, Fuehrer HP, Eisenmann A, Landis RC, Steininger C Medical University of Vienna/ Abteilung für Infektiologie und Tropenmedizin, Wien, Austria

Mosquitoes are the most important vectors for arthropod born virus infections on a global scale. Human pathogenic arboviruses, constitute only a minor fraction of the mosquito virome, however, viral co-infection of mosquitos can alter replication and transmission of human pathogenic arboviruses. In a previous metagenomic virome study we found that Aedes aegypti mosquitos harbor a rich and highly diverse set of viruses. Beside 39 viral hits we detected a vast set of viral sequences with high degree of novelty. Among them we identified and characterized the full length genome of a novel CRESS (circular Rep- encoding single stranded) DNA virus. By specific qPCR assays we were able to confirm our metagenomic findings, revealing a 2,2kb circular genome, coding for 2 viral proteins. Phylogenetic analysis placed the virus in the taxonomic family of Genomoviridae. Virus host association for members of this family has yet been confirmed only for a single plant infecting virus. By characterizing a yet unknown member of the viral microbiome of Aedes aegypti, this study might contribute to a better understanding of virus- host interactions and trans kingdom virus transmissibility.

Poster 33 Synergistic interactions in mixed-opportunistic pathogens biofilms under stress conditions Wisnu Adi Wicaksono, Henry Müller, Tomislav Cernava, Gabriele Berg Institute of Environmental Biotechnology, TU Graz, Austria

In nature, bacteria commonly reside by producing multicellular surface-associated communities embedded in an extracellular polymeric substances (EPS) known as biofilms. Biofilm feature could be a problem for human health as human opportunistic pathogens usually possess this feature to be able to thrive in built environment. Multispecies biofilms are more resistant against antimicrobials compared to single species biofilm. However, the mechanisms underlying this interaction are still scarce. As biofilm of opportunistic pathogen appears to facilitate the survival of these pathogen in the built environment, here we report biofilm interaction analysis from single and mixed species of selected clinical and environmental opportunistic pathogen namely Acinetobacter baumanii, Enterococcus faecium, Escherichia coli, Staphylococcus haemolyticus (coagulase-negative staphylococci) and Stenotrophomonas maltophilia. We exposed them against stress factors i.e. antimicrobial exposure and nutrient-poor environment that commonly occur in a hospital setting. We combined whole genome sequencing analysis, biofilm formation analysis using crystal violet (CV) and RNA sequencing in order to understand effect of the stress factors on biofilm formation and bacterial resistance. By combining these approaches, we address the following questions. (i) Do the stress factors induce biofilm formation on single and mixed opportunistic pathogens? (ii) What are the ecological roles of member of bacteria in mixed biofilm species? (iii) Which potential molecular mechanisms underpinning multispecies interaction? We demonstrate synergistic effects in mixed biofilm species under stress pressure. Importantly, minor but antimicrobial resistance species are important for the biofilm formation, led to an increase in the overall yield of the mixed biofilm community under antimicrobial exposure.

Poster 34 Exploring the Microbiome of Ugandan Leafy Greens Olivia Laggner, Julian Taffner, Adrian Wolfgang, Lea Gibitz-Lambert, Gabriele Berg acib GmbH, Graz, Austria, Institute of Environmental Biotechnology, TU Graz, Austria

Indigenous leafy greens, such as Okra (Abelmoschus esculentus), Garden huckleberry (Solanum scabrum), Spider whisp (Gynandropsis gynandra), and Black Jack (Bidens pilosa) were recently rediscovered for rural medicine and cuisine in East Africa. Compared to cultivated crops, those plants struggle less from pests and are generally more robust to abiotic stresses. The robustness of the host plant is strongly depending on its microbiome. In order to better understand the role of beneficial bacteria, the microbiome of the four leafy greens was characterized based on 16S rRNA gene fragment amplicon sequencing and bioinformatics analysis. Additionally, bacteria from each plant were isolated and screened for antagonistic activity against main phytopathogenic fungi (Botrytis cinerea, Fusarium oxysporum, Fusarium verticillioides, Sclerotium rolfsii and Verticillium dahliae). The identified antagonists were further tested for their ability to resist abiotic stresses, such as salinity, drought, and reactive oxygen.

Poster 35 The potential of vegetable and leafy greens microbiota to enhance crop health in Uganda Olivia Laggner, Adrian Wolfgang, Julian Taffner, Gabriele Berg Institute of Environmental Biotechnology, TU Graz, Austria

Establishing a self-supporting agriculture in Sub-Saharan Africa is a major challenge due to an increasing human population, limited technical and educational resources, as well as climate change-related weather effects. In order to provide plant health-enhancing, microbe-based strategies for agriculture, we analyzed the bacterial and archaeal community in rhizosphere, rhizoendosphere and/or phyllosphere of five crops, namely tomato (Solanum lycopersium), Okra (Abelmoschus esculentus), Nightshade (Solanum scabrum), Spiderplant (Cleome gynandra) and Black Jack (Bidens pilosa) using 16S rRNA amplicon sequencing. Plant-associated bacterial isolates were tested for antagonism towards fungal phytopathogens (Botrytis cinerea, Fusarium oxysporum, Fusarium verticillioides, Sclerotium rolfsii, Verticillium dahliae) in dual culture assays and for production of nematicidal volatiles against Meloidogyne incognita. Additionally, bacterial isolates were tested for the ability to resist abiotic stressors, such as salinity, drought, and reactive oxygen. We found microbiomes of leafy greens (Okra, Nightshade, Spiderplant, Black Jack) to be significantly more diverse than of cultivated crops. Microhabitat is the driving factor of microbial diversity and has a bigger impact on community composition than plant species. For archaea, Thaumarchaeota were the dominant taxa. Six strains of the genera Pseudomonas, Comamonas and Variovorax showed antagonistic effects on Meloidogyne incognita J2 larvae through volatiles. Isolated Sphingomonas spp. (n = 8) and Bacillus spp. (n = 21) were found to be promising candidates as biocontrol agents for phytopathogenic fungi. Those isolates partially stand high salinity (up to 11% NaCl) and drought (cultivable after >3 months desiccation). This study comprises biocontrol agents that may optimize vegetable production for smallholders in East Africa.