Resumo: O cultivo intensivo agrícola, apesar de altamente produtivo, possui diversos pontos questionáveis, como suplementação acentuada de insumos sintéticos, além da aplicação de defensivos para o controle de pragas que muitas vezes são danosos ao meio ambiente. Como alternativa, a agricultura orgânica propõe uma forma de manejo menos agressiva, que promove o uso sustentável dos recursos naturais renováveis, como o aproveitamento de resíduos orgânicos, além de possuir um maior valor agregado no produto final. No presente estudo, investigamos por meio de uma abordagem metagenômica os efeitos do manejo (orgânico ou convencional) na microbiota da rizosfera de cana-de-açúcar, região da planta que notoriamente causa um grande impacto no seu desenvolvimento e produtividade. Identificamos a abundância maior na rizosfera com manejo orgânico de porções genômicas que codificam enzimas associadas ao metabolismo do nitrogênio e enxofre, sendo que estes são nutrientes fundamentais para o sucesso da planta e assim, seu desenvolvimento e produtividade em campo. Contraditoriamente, encontramos também que os genomas da microbiota orgânica possuem conteúdo ligado a um potencial mais acentuado para a degradação de compostos xenobióticos, que são ativamente aplicados no manejo convencional. De acordo com nossa predição, os microrganismos dessa microbiota poderiam realizar sua completa mineralização, o que é muito favorável na remoção desses resíduos no ambiente. Esses achados indicam que há um potencia... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Modern industrialized agriculture although highly productive, has several sustainability problems such as the for intense supplementation of synthetic inputs, beyond the application of pesticides for pest control. Which are often harmful to environment. As an alternative to this system, organic agriculture is considered more environmentally progressive, having several characteristics favorable to the crop producer, promotes sustainable use of renewable natural resources, such as the use of organic waste, besides that a higher aggregated value in the final product. This study investigates the changes that an organic system brings when compared to conventional management for the sugarcane rhizosphere microbiome, a plant region known to be determinant of plant development and associated with net productivity, using a metagenomic approach. We identified a higher abundance of genomic portions which encode enzymes associated with nitrogen and sulphur metabolism, which are fundamental nutrients for plant success and subsequently, crop productivity. Conversely, we also found that genomes of the organic microbiome contain higher portions linked to xenobiotic degradation, compounds that are actively applied in conventional management. Microorganisms from this sequenced microbiome could perform complete mineralization of these damaging compounds, which is desirable in their removal from the environment. These findings indicate that there is a unique potential for exploitation of organic... (Complete abstract click electronic access below) / Mestre

Restriction endonucleases are a group of enzymes that cleave DNA at or around specific sequences, which are typically palindromic. A fosmid library was constructed from a metagenome isolated from soil from the Kogelberg Nature Reserve, Western Cape and was functionally screened for restriction endonucleases. Next-generation (NGS) Illumina sequencing technology was used to identify putative endonucleases. The sequence data generated was assembled and analysed using CLC Bio Genomics Workbench and bioinformatics tools (NCBI BLAST, REBASE and MG-RAST). Using these tools, genes encoding restriction-modification systems and endonuclease homologues were discovered. Three genes were identified and were recombinantly produced in Rosetta™ (DE3) pLysS and purified with IMAC using Ni-TED resin and subsequently characterised. These three genes were selected based on the identity percentage when compared to sequences on the NCBI database. Production of Endo8 was scaled up using 2 l fermenter and the purification done using ÄKTA Avant 150 FPLC using a HiScale 50 column packed with Ni-TED resin and the total amount of protein achieved was 58.82 mg.g-1. The productivity achieved at 17 hours (8 h harvest) was 2-fold greater than at 12 hours. Endonuclease activity of endo8 and endo52 was tested, both exhibited strong non-specific activity at 37 °C with an incubation period of 30 min. This work demonstrates that environmental soil samples are a valuable source for discovery of novel enzymes and also the utility of functional metagenomics to discover and purify these enzymes. These endonucleases may contribute to the next generation of reagent enzymes for molecular biology research. / Chemistry / M. Sc. (Life Sciences)

Submitted by Priscila Nascimento (pnascimento@icict.fiocruz.br) on 2013-03-22T18:57:42Z No. of bitstreams: 1 Bruno_Gabriel_N_Andrade.pdf: 1653673 bytes, checksum: 187a641b69c50d36212eb943747940e5 (MD5) / Made available in DSpace on 2013-03-22T18:57:42Z (GMT). No. of bitstreams: 1 Bruno_Gabriel_N_Andrade.pdf: 1653673 bytes, checksum: 187a641b69c50d36212eb943747940e5 (MD5) Previous issue date: 2012 / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil. / As Metallo-β-Lactamases (Mβls) são uma família de enzimas cuja importância clínica reside na sua capacidade de hidrolisar praticamente todos os antibióticos da classe dos β-Lactâmicos, incluindo as carbapenemas, que são os compostos mais poderosos utilizados atualmente, a única exceção são os monobactâmicos. Estas enzimas são classificadas em três subclasses, B1, B2 e B3, com base nas suas identidades em nível de sequência e perfil de atividade. As enzimas das subclasses B1 e B3, caracterizam-se por ter amplo espectro de ação enquanto que, as da subclasse B2, são carbapenemases estritas. O conjunto de genes associados à resistência das bactérias aos antimicrobianos, presentes em um determinado ambiente, é conhecido como “Resistoma”. Evidências caracterizam a microbiota de ambientes naturais como fonte e/ou reservatório destes genes e o resistoma ambiental como reservatório original das Mβls. Nosso estudo tem como objetivo buscar em projetos de metagenomas marinhos públicos evidências da existência de um resistoma neste bioma. Buscamos, in silico, por Mβls putativas similares àquelas encontradas em bactérias presentes em ambientes clínicos. Os projetos de metagenomas marinhos públicos foram obtidos no banco de armazenamento do Cyberinfrastructure for Advanced Microbial Research (CAMERA), buscas por Metallo-β-Lactamases foram feitas com o software HMMer V3, empregando um limiar de similaridade baseado em um e-value de 10-20, utilizando os alelos de Metallo-β-Lactamases conhecidos para a construção de perfis HMM, empregados como sondas. Para determinar a relação com as Metallo-β-Lactamases clínicas, uma segunda busca foi feita com os resultados do HMMer contra o banco de dados de proteínas não redundantes (NR) utilizando o programa Blastp do pacote Blast+. Motivos conservados característicos das Mβls foram identificados visualmente para a eliminação de falsos positivos, análises filogenéticas foram feitas utilizando o programa MEGA v5. Identificamos, em sítios de vários oceanos e mares, sequências apresentando Mβls putativas, apresentando similaridade de sequência estatisticamente relevante com Mβls clínicas, como: VIM, CFIA, BLAB, SPM, CPHA, GOB, L1, FEZ1 e CAU-1. Algumas destas Mβls putativas apresentaram identidade de sequência com suas similares clínicas, as Mβls VIM e SPM. Nossa análise mostrou que a Mβl GOB apresenta uma grande abundância e dispersão. Assim, apresentamos as primeiras evidências da existência de um resistoma marinho, caracterizado pela presença de sequências das três subclasses de Mβls e com ampla distribuição pelo meio marinho. / The Metallo-β-lactamases (Mβls) are a family of enzymes with high impact in the clinic due to their ability to hydrolyze virtually all antibiotics belonging to the β-lactams group, excluding the monobactams. These enzymes are classified into three subclasses, B1, B2 and B3, based on their sequence similarity and the activity profile. The enzymes from subclass B1 and B3 present a broad spectrum of activity and the subclass B2 are strict carbapenemases. The set of genes associated with bacteria antimicrobial resistance present in an environment is known as “Resistome”. Studies have presented evidences characterizing the microbiota of natural environments as the source and/or reservoir of resistance genes and the environmental resistome as the original reservoir of Mβls. Our study aims to search publicly available marine metagenome projects for evidences of a marine resistome. We performed an in silico analysis to reveal putative Mβls that are similar to those found in the clinical setting. The marine metagenomic were downloaded from the Cyberinfrastructure for Advanced Microbial Research (CAMERA), and screened for Metallo-β-lactamases with the HMMer V3 software, with similarity threshold of an e-value of 10-20, using the known Metallo-β- lactamases alleles to build HMM profiles, and used them as queries. In order to determine the relationship between these two groups, the results were queried against the NCBI non-redundant protein database using the Blastp software with the same e-value cutoff. The Mβl motifs were visually identified to eliminate false positives, and phylogenetic analysis were made using the MEGA v5 software. Putative sequences showing identity with clinical Mβls, such as: VIM, CFIA, BLAB, SPM, CPHA, GOB, L1, FEZ1 and CAU-1 were found in samples from distinct oceans. Our analysis showed that the Mβl GOB is variable and dispersed in various sites of the oceans. Thus, we could map and bring evidences of the marine resistome based on the presence of the three subclasses of Mβls distributed in the ocean.

Submitted by Aelson Maciera (aelsoncm@terra.com.br) on 2017-05-25T18:55:01Z No. of bitstreams: 1 DissAFB.pdf: 2608429 bytes, checksum: 95d0acfb93ac8153ab8599ee86111dff (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-05-30T12:35:23Z (GMT) No. of bitstreams: 1 DissAFB.pdf: 2608429 bytes, checksum: 95d0acfb93ac8153ab8599ee86111dff (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-05-30T12:35:43Z (GMT) No. of bitstreams: 1 DissAFB.pdf: 2608429 bytes, checksum: 95d0acfb93ac8153ab8599ee86111dff (MD5) / Made available in DSpace on 2017-05-30T12:40:32Z (GMT). No. of bitstreams: 1 DissAFB.pdf: 2608429 bytes, checksum: 95d0acfb93ac8153ab8599ee86111dff (MD5) Previous issue date: 2017-02-15 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Metagenomics studies allow the direct analysis of a genetic material in an environmental sample and when linked to bioinformatics it gives a powerful tool to explore the role of new genes and proteins not studied before. Constant decreases in the quantity of fossil fuels and their effects in the global economy and natural environment has accelerated researches in alternative fuels such as the second generation ethanol, which can be produced by vegetation biomass. However, this process demands previous hydrolysis of the lignocellulolytic material by hydrolytic enzymes to provide fermentable sugar. β-glucosidases are enzymes which plays an important role at the final step of cellulose breakdown to glucose, thus being considered the rate limiting enzyme in this process of biomass degradation. Many β-glucosidases are already known, however there is an interest to find new enzymes which are tolerant to glucose inhibition and which exhibits high activity at lower temperatures. In this study we searched for β-glucosidases (GH1) using sequences from a metagenomics database from rivers and lakes in the Amazon region developed in our laboratory. We found 3 complete open reading frames (ORFs) related to β-glucosidases and one of them was selected to be produced in E.coli in a heterologous way and to be biochemically characterized. The coding sequence of the protein named AmBgl1-LP was cloned in the plasmid pET-28a and produced an enzyme which has a molecular mass of 53,7 kDa. The enzymatic assays showed that the enzyme was active with an optimum pH of 5.5, optimum temperature of 35 °C and had a Ki for glucose of 23 mM. The enzyme does not apparently perform transgycosylation, according to the assays for pNPβGlu substrate. Supposedly, AmBgl1-LP suffers inhibition by pNPβGlu on concentrations higher than 10 mM. The enzyme showed to be capable of hydrolyzing cellobiose, pNPβGal and pNPβFuc. Thus, the enzyme is promising for use in cocktails for degradation of biomass. / A metagenômica permite estudar diretamente o material genético presente em uma amostra ambiental e quando aliada à bioinformática possibilita explorar o papel de novos genes e proteínas. A constante diminuição na quantidade de combustíveis fósseis e seus efeitos na economia global e no meio ambiente têm acelerado as pesquisas sobre combustíveis alternativos como, por exemplo, o etanol de segunda geração, o qual pode ser obtido a partir de biomassa vegetal. No entanto, o processo necessita que o material lignocelulolítico seja hidrolisado previamente por enzimas, para o fornecimento de açúcares fermentescíveis. As β-glicosidases são enzimas que participam da etapa final de degradação de celulose em glicose e são, portanto, consideradas passo limitante no processo. Muitas β-glicosidases já foram descritas, entretanto ainda há o interesse em encontrar enzimas que sejam resistentes à inibição por glicose e que exerçam sua atividade em temperaturas mais baixas. Neste sentido, o presente trabalho tratou da busca por β-glicosidases da família GH1 utilizando sequências obtidas a partir de um estudo metagenômico de rios e lagos da Amazônia, realizado em nosso laboratório. Foram encontradas 3 fases abertas de leitura (ORFs) correspondentes à esta classe de enzimas e uma delas foi selecionada para ser produzida em E.coli de forma recombinante e ser caracterizada bioquimicamente. A sequência que codifica a proteína denominada AmBgl1-LP foi clonada em vetor pET-28a e expressa em E.coli, rendendo uma enzima com massa molecular de 53,7 kDa. Os ensaios de atividade enzimática revelaram que a enzima é ativa em pH ótimo de 5,5 e temperatura ótima de 35 °C. Além disso, a enzima possui um Ki para glicose de 23 mM. A enzima aparentemente não realiza transglicosilação, frente aos ensaios com o substrato pNPβGli. Aparentemente a enzima sofre inibição por este substrato em concentrações maiores que 10 mM. A AmBgl1-LP mostrou-se capaz de hidrolisar celobiose, além de pNPβGal e pNPβFuc. Desta forma, a enzima mostra-se promissora para utilização em coquetéis para degradação de biomassa.

Made available in DSpace on 2014-12-17T14:03:36Z (GMT). No. of bitstreams: 1 RalfoGP_DISSERT_partes_autorizadas.pdf: 608925 bytes, checksum: dbfcce5de284f89c5cdaee179cdd9bc2 (MD5) Previous issue date: 2010-12-02 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The microorganisms play very important roles in maintaining ecosystems, which explains the enormous interest in understanding the relationship between these organisms as well as between them and the environment. It is estimated that the total number of prokaryotic cells on Earth is between 4 and 6 x 1030, constituting an enormous biological and genetic pool to be explored. Although currently only 1% of all this wealth can be cultivated by standard laboratory techniques, metagenomic tools allow access to the genomic potential of environmental samples in a independent culture manner, and in combination with third generation sequencing technologies, the samples coverage become even greater. Soils, in particular, are the major reservoirs of this diversity, and many important environments around us, as the Brazilian biomes Caatinga and Atlantic Forest, are poorly studied. Thus, the genetic material from environmental soil samples of Caatinga and Atlantic Forest biomes were extracted by direct techniques, pyrosequenced, and the sequences generated were analyzed by bioinformatics programs (MEGAN MG-RAST and WEBCarma). Taxonomic comparative profiles of the samples showed that the phyla Proteobacteria, Actinobacteria, Acidobacteria and Planctomycetes were the most representative. In addition, fungi of the phylum Ascomycota were identified predominantly in the soil sample from the Atlantic Forest. Metabolic profiles showed that despite the existence of environmental differences, sequences from both samples were similarly placed in the various functional subsystems, indicating no specific habitat functions. This work, a pioneer in taxonomic and metabolic comparative analysis of soil samples from Brazilian biomes, contributes to the knowledge of these complex environmental systems, so far little explored / Os microorganismos desempenham importantes fun??es na manuten??o dos ecossistemas, o que explica o enorme interesse em compreender as rela??es existentes entre estes organismos, bem como entre eles e o meio. Estima-se que o n?mero total de c?lulas procari?ticas na Terra seja entre 4 e 6 x 1030, constituindo um enorme pool biol?gico e gen?tico a ser explorado. Apesar de atualmente apenas 1% de toda essa riqueza poder ser cultivada por t?cnicas laboratoriais padr?o, ferramentas metagen?micas permitem o acesso ao potencial gen?mico de amostras ambientais de forma independente de cultivo, e em associa??o com tecnologias de sequenciamento da terceira gera??o, a cobertura amostral se torna ainda maior. Solos, em particular, s?o os maiores reservat?rios dessa diversidade, e muitos ambientes importantes ao nosso redor, como os biomas brasileiros Caatinga e Mata Atl?ntica, s?o pouco estudados. Sendo assim, o material gen?tico ambiental de amostras de solo dos biomas Caatinga e Mata Atl?ntica foi extra?do atrav?s de t?cnicas diretas, pirosequenciado, e as seq??ncias geradas foram analisadas atrav?s de programas de bioinform?tica (MEGAN, MG-RAST e WEBCarma). Perfis taxon?micos comparativos das amostras mostraram que os filos Proteobacteria, Actinobacteria, Acidobacteria e Planctomycetes foram os mais representativos. Em adi??o, fungos do filo Ascomycota foram identificados predominantemente na amostra de solo de Mata Atl?ntica. Perfis metab?licos mostraram que, apesar da exist?ncia de diferen?as ambientais, sequ?ncias de ambas as amostras foram inseridas similarmente nos diversos subsistemas funcionais, n?o indicando fun??es habitat espec?ficas. Este trabalho, pioneiro em an?lises taxon?micas e metab?licas comparativas de amostras de solo de biomas brasileiros, contribui para o conhecimento destes sistemas ambientais complexos, at? ent?o pouco explorados

A cana-de-açúcar é uma cultura agrícola de grande importância econômica para o Brasil, e a expansão de seu cultivo para solos marginais requer uma maior utilização de fertilizantes à base de nitrogênio (N). Na maioria dos países produtores, a adubação nitrogenada se baseia em altas doses de aplicação, enquanto, no Brasil, o seu uso é relativamente baixo devido, em parte, ao processo de fixação biológica de nitrogênio (FBN) pela ação de bactérias diazotróficas. Além da FBN, as plantas adquirem fontes de N, como amônio e nitrato, por meio de transportadores de membranas localizados nas raízes. Há evidências que a associação com microrganismos pode favorecer as plantas por meio da regulação dos genes de transportadores de N. Desta forma, este trabalho teve como objetivo caracterizar o transporte de amônio e nitrato, avaliando a expressão gênica dos principais transportadores de N em cana-de-açúcar cultivada in vitro sob o efeito da associação com bactérias diazotróficas. Também foi descrita a comunidade bacteriana de plântulas in vitro, bem como o efeito da fertilização com N e da inoculação com bactérias diazotróficas em plantas maduras. Plântulas de \'SP70- 1143\' e \'Chunee\', que contrastam para FBN, foram empregadas em ensaios in vitro sob diversas concentrações e fontes de N em associação ou não com uma estirpe de Gluconacetobacter diazotrophicus ou um mistura de bactérias diazotróficas (G. diazotrophicus, Herbaspirillum seropedicae, H. rubrisubalbicans, Azospirillum amazonense e Burkholderia tropica). A caracterização do transporte de N por meio de ensaios de absorção de nitrato e amônio marcados (15N) revelou que a interação entre cana-de-açúcar x G. diazotrophicus induziu a expressão do gene do transportador de nitrato ScNRT2.1, o que levou a uma tendência no aumento no influxo de nitrato, assim como dos genes de transportadores de amônio ScAMT1.1 e ScAMT1.3, resultando em maiores influxos de amônio apenas para a cultivar \'SP70- 1143\'. Já a associação da cana-de-açúcar com a mistura de bactérias diazotróficas revelou que somente houve indução transcricional de ScAMT1.1, o que resultou na maior absorção de amônio em \'SP70-1143\'. Por sua vez, quando analisada a interação in vitro por 30 dias, a presença da bactéria, apesar de transiente, possivelmente favoreceu a expressão dos genes de transportadores de nitrato ScNRT1.1 e ScNRT2.1, e do transportador de amônio ScAMT1.1, resultando no maior acúmulo de 15N-nitrato de amônio nas plantas de \'SP70-1143\'. Foi detectada uma comunidade bacteriana associada a plântulas micropropagadas, a qual é distinta entre os genótipos \'SP70-1143\' e \'Chunee\' e se altera com a inoculação com G. diazotrophicus. Para as plantas cultivadas em campo, a comunidade bacteriana existente foi alterada pela fertilização de N, mas não pela inoculação com diazotróficas. Portanto, a inoculação com bactérias diazotróficas parece induzir a expressão dos principais genes transportadores de amônio e nitrato em plântulas do genótipo \'SP70-1143\' resultando na maior absorção de fontes inorgânicas de N. / Sugarcane has a large economic importance to Brazil, and it\'s the expansion of cultivation to marginal soils requires a larger application of nitrogen fertilizers (N) to maintain yield. In most producing countries, N fertilization is based on high application rates, whereas in Brazil N fertilization is relatively low, possibly due in part, to the process of biological nitrogen fixation (BNF). In addition, plants acquire inorganic N sources from the soil by membrane transporters that may be regulated by association with microorganisms. This study aimed to characterize the ammonium and nitrate transport evaluating the gene expression profile of the major transporters grown in vitro in association with diazotrophic bacteria. It was also described the bacterial community in micropropagated plants, as well as the effect of N fertilization or inoculation with nitrogen fixing bacteria in mature plants. \'SP70-1143\' and \'Chunee\' which contrasted to BNF, were used in in vitro experiments in several concentrations and N source, in association or not with a strain of Gluconacetobacter diazotrophicus or a bacteria mixture (G. diazotrophicus, Herbaspirillum seropedicae, H. rubrisubalbicans, Azospirillum amazonense and Burkholderia tropica). The characterization of the N transport by uptake assays with 15N-labeled ammonium and nitrate, revealed that the interaction between sugarcane x G. diazotrophicus induced, the nitrate transporter gene ScNRT2.1 expression, which lead to trend to increase nitrate influx, as well as the ammonium transporter genes ScAMT1.1 and ScAMT1.3, resulting in higher ammonium influx in \'SP70-1143\'. Sugarcane associated with the bacterial mixture revealed a transcriptional induction of ScAMT1.1 resulting in larger ammonium acquisition in \'SP70-1143\'. Further, the presence of bacteria in vitro for 30 days, although transient, possibly favored the expression of nitrate transporters ScNRT1.1 and ScNRT2.1, and the ammonium transporter ScAMT1.1, resulting in accumulation of 15N-ammonium nitrate in \'SP70-1143\'. A bacterial community associated with in vitro plants of \'SP70-1143\' and \'Chunee\' was detected with different composition between genotypes, and which changed with artificial inoculation. For plants grown in the field, the bacterial community was affected by N fertilization but not by inoculation with diazotrophic. These results indicate that the inoculation with diazotrophic bacteria appears to induce the expression of the major ammonium and nitrate transporters genes in \'SP70-1143\' plants resulting in higher uptake of inorganic N sources.

No description available.

As international travel is rapidly increasing, more people are being exposed to potentially more antibiotic resistant bacteria, a changed infectious disease epidemiology, and an increased risk of accidents and crime. Research-based advice is needed to adequately inform travellers about these risks. We studied travellers who sought advice from the Travel Medicine Clinic at the Department of Infectious Diseases, Umeå University Hospital, as well as university students from Umeå, Stockholm, and Gothenburg travelling abroad for study, research, and clinical exchange programs. From retrospective data at the Travel Medicine Clinic, we found that pre-existing health problems were rare among travellers from Umeå seeking pre- travel health advice and vaccinations. In addition, we found that the travel destination and the sex of the traveller affected vaccination levels. Although hepatitis A is endemic to both Thailand and Turkey, compared to travellers to Thailand few travellers to Turkey visited the clinic for hepatitis A vaccination. The data also revealed that more women than men were vaccinated against Japanese encephalitis despite comparable trips. A prospective survey study showed that travellers felt that the pre-travel health advice they received was helpful. Two-thirds of the travellers followed the advice given although they still fell ill to the same extent as those who were not compliant with the advice. Factors outside the control of travellers likely affect the travel-related morbidity. Compared to older travellers, younger travellers were less compliant with advice, fell ill to a greater extent, and took greater risks during travel. In a prospective survey study, we found that healthcare students had higher illness rates and risk exposure when abroad compared to students from other disciplines. This difference was mainly due to the fact that healthcare students more often travelled to developing regions during their study period abroad. When abroad, half of all students increased their alcohol consumption and this was linked to an increased risk of theft and higher likelihood of meeting a new sex partner. The healthcare students participating in the survey study also submitted stool samples before and after travel. These samples were tested for the presence of antibiotic resistance, both by selective culturing for ESBL-PE (Extended-Spectrum Beta-Lactamase Producing Enterobacteriaceae) as well as by metagenomic sequencing. About one-third (35%) of the students became colonised by ESBL-PE following their study abroad. The strongest risk factor for colonisation was travel destination; for example, 70% of students who had travelled to India became colonised. Antibiotic treatment during travel was also a significant risk factor for colonisation. The stool samples from a subset of study subjects were analysed using metagenomic sequencing. From this we learned that although the majority of resistance genes in the gut microbiome remained unchanged following travel, several clinically important resistance genes increased, most prominently genes encoding resistance to sulphonamide, trimethoprim, and beta-lactams. Overall, taxonomic changes associated with travel were small but the proportion of Proteobacteria, which includes several clinically important bacteria (e.g., Enterobacteriaceae), increased in a majority of the study subjects. Clearly, there are risks associated with international travel and these risks include outside factors as well as the personal behaviour of travellers. We believe our results can be used to develop better pre-travel advice for tourists as well as university students studying abroad resulting in safer travel.

No description available.

No description available.