The Human Gut Microbiome as a Transporter of Antibiotic Resistance Genes between Continents.

Previous studies of antibiotic resistance dissemination by travel have, by targeting only a select number of cultivable bacterial species, omitted most of the human microbiome. Here, we used explorative shotgun metagenomic sequencing to address the abundance of >300 antibiotic resistance genes in fecal specimens from 35 Swedish students taken before and after exchange programs on the Indian peninsula or in Central Africa. All specimens were additionally cultured for extended-spectrum beta-lactamase (ESBL)-producing enterobacteria, and the isolates obtained were genome sequenced. The overall taxonomic diversity and composition of the gut microbiome remained stable before and after travel, but there was an increasing abundance of Proteobacteria in 25/35 students. The relative abundance of antibiotic resistance genes increased, most prominently for genes encoding resistance to sulfonamide (2.6-fold increase), trimethoprim (7.7-fold), and beta-lactams (2.6-fold). Importantly, the increase observed occurred without any antibiotic intake. Of 18 students visiting the Indian peninsula, 12 acquired ESBL-producing Escherichia coli, while none returning from Africa were positive. Despite deep sequencing efforts, the sensitivity of metagenomics was not sufficient to detect acquisition of the low-abundant genes responsible for the observed ESBL phenotype. In conclusion, metagenomic sequencing of the intestinal microbiome of Swedish students returning from exchange programs in Central Africa or the Indian peninsula showed increased abundance of genes encoding resistance to widely used antibiotics.

Illness and risk behaviour in health care students studying abroad.

CONTEXT: The numbers of university students studying abroad increase every year. These students are not tourists as their studies require different types of travel that expose them to different risks. Moreover, health care students (HCSs) may be exposed to even greater risks according to their travel destinations and itineraries. Clearly, research-based pre-travel advice is needed. METHODS: This study reports on a prospective survey conducted from April 2010 to January 2014 of health care and non-health care students from Swedish universities in Umeå, Stockholm and Gothenburg studying abroad. RESULTS: Of the 393 students included in the study, 85% responded. Over half (55%) were HCSs. Pre-travel health information was received by 79% and information on personal safety by 49% of HCSs. The rate of illness during travel was 52%. Health care students more often travelled to developing regions and were at increased risk for travellers' diarrhoea. One in 10 experienced theft and 3% were involved in traffic accidents. One in five met a new sexual partner during travel and 65% of these practised safe sex. Half of all participants increased their alcohol consumption while abroad; high alcohol consumption was associated with increased risk for being a victim of theft, as well as for meeting a new sexual partner during travel. CONCLUSIONS: University authorities are responsible for the safety and well-being of students studying abroad. This study supplies organisers and students with epidemiological data that will help improve pre-travel preparation and increase student awareness of the potential risks associated with studying abroad.

Spatiotemporal characteristics of pandemic influenza.

BACKGROUND: Prediction of timing for the onset and peak of an influenza pandemic is of vital importance for preventive measures. In order to identify common spatiotemporal patterns and climate influences for pandemics in Sweden we have studied the propagation in space and time of A(H1N1)pdm09 (10,000 laboratory verified cases), the Asian Influenza 1957-1958 (275,000 cases of influenza-like illness (ILI), reported by local physicians) and the Russian Influenza 1889-1890 (32,600 ILI cases reported by physicians shortly after the end of the outbreak). METHODS: All cases were geocoded and analysed in space and time. Animated video sequences, showing weekly incidence per municipality and its geographically weighted mean (GWM), were created to depict and compare the spread of the pandemics. Daily data from 1957-1958 on temperature and precipitation from 39 weather stations were collected and analysed with the case data to examine possible climatological effects on the influenza dissemination. RESULTS: The epidemic period lasted 11 weeks for the Russian Influenza, 10 weeks for the Asian Influenza and 9 weeks for the A(H1N1)pdm09. The Russian Influenza arrived in Sweden during the winter and was immediately disseminated, while both the Asian Influenza and the A(H1N1)pdm09 arrived during the spring. They were seeded over the country during the summer, but did not peak until October-November. The weekly GWM of the incidence moved along a line from southwest to northeast for the Russian and Asian Influenza but northeast to southwest for the A(H1N1)pdm09. The local epidemic periods of the Asian Influenza were preceded by falling temperature in all but one of the locations analysed. CONCLUSIONS: The power of spatiotemporal analysis and modeling for pandemic spread was clearly demonstrated. The epidemic period lasted approximately 10 weeks for all pandemics. None of the pandemics had its epidemic period before late autumn. The epidemic period of the Asian Influenza was preceded by falling temperatures. Climate influences on pandemic spread seem important and should be further investigated.

Travel health advice: benefits, compliance, and outcome.

BACKGROUND: Travel health advice is an important and difficult part of a pre-travel consultation. The aim of this study was to determine whether the travel health advice given is followed by the traveller and whether it affects disease and injury experienced during travel. METHODS: A prospective survey study was carried out from October 2009 to April 2012 at the Travel Medicine Clinic of the Department of Infectious Diseases, Umeå University Hospital, Umeå, Sweden. The Travel Medicine Clinic in Umeå is the largest travel clinic in northern Sweden. RESULTS: We included 1277 individuals in the study; 1059 (83%) responded to the post-travel questionnaire. Most visitors (88%) remembered having received travel health advice; among these, 95% found some of the health advice useful. Two-thirds (67%) claimed to have followed the advice, but fell ill during travel to the same extent as those who did not. Younger travellers (< 31 y) found our travel health advice less beneficial, were less compliant with the advice, took more risks during travel, and fell ill during travel to a greater extent than older travellers. CONCLUSIONS: Helping travellers stay healthy during travel is the main goal of travel medicine. Younger travellers are a risk group for illness during travel and there is a need to find new methods to help them avoid illness. Travellers find travel health advice useful, but it does not protect them from travel-related illness. Factors not easily influenced by the traveller play a role, but a comprehensive analysis of the benefits of travel health advice is needed.

Travel and vaccination patterns: a report from a travel medicine clinic in northern Sweden.

BACKGROUND: The Travel Medicine Clinic in Umeå is one of Sweden's largest public providers of vaccination and counselling prior to international travel. During the study period it was the only travel medicine clinic in Umeå. This study describes the demography of the visitors to the clinic and travel destinations and durations, as well as vaccinations administered. METHODS: This was a retrospective study for the period January 2005 to April 2008 based on pre-travel consultation questionnaires and on vaccine expenditure data. A 10% sample of 16,735 first visits prior to international travel was consecutively selected according to the chronology of the visits. RESULTS: Data on 1698 travellers were included in the study. Thailand was the most common destination among visitors, accounting for one third of all destinations. Medical problems affecting pre-travel health planning were rare. Four out of 5 visitors (79%) received only 1 vaccination, mainly for hepatitis A. Travellers to Thailand more often sought travel health advice compared to travellers to Turkey, despite the fact that the 2 destinations were almost equally distributed among travellers from Umeå. We found differences between men and women in money spent on vaccines and in particular in vaccination against Japanese encephalitis. CONCLUSIONS: To assess the optimal vaccination level at a travel medicine clinic is difficult. Decisions are affected by general recommendations and the risk perception of the travel medicine practitioner, as well as the risk perception of the traveller. The sex difference found in this study might be due to gender differences in risk perception and should be further investigated.

Health education and communication in Occupational Health Services in Finland.

This article discusses health education and communication in Occupational Health Services (OHS) based on a questionnaire study conducted in Finnish OHS in 2005. The study focused on educational activities carried out by OH professionals and directed at individual employees, work communities and groups, and representatives of client organisations. The questionnaire was sent to 1132 OH professionals--physicians, nurses, physiotherapists and psychologists--working in 130 OHS units, and representing different OHS providers in Finland. 635 respondents (162 physicians, 342 nurses, 96 physiotherapists, 35 psychologists) returned the questionnaire. The overall response rate was 58%. There were statistically significant differences in educational activities by different professional groups; differences were also related to the length of working experience in OHS. For all OH professionals, individual employees were the primary clients of health education and communication. Education was less often directed at work communities and representatives of client organisations. However, many issues related to health and well-being at work are not within the reach of individual employees. The impact of health education would be more evident if it also reached those organisational stakeholders with discretion in decision-making. Furthermore, OH personnel should pay attention to the social aspect of learning and work more with groups and work communities.

In search of human-associated bacterial pathogens in Antarctic wildlife: report from six penguin colonies regularly visited by tourists.

We investigated the potential role of Antarctic tourism in the introduction of human-associated pathogens into Antarctic wildlife. We collected and analyzed 233 fecal samples from eight bird species. The samples were collected at six localities on the Antarctic Peninsula, which often is visited by tourists. Every sample was investigated for pathogens of potential human origin: Campylobacter jejuni, Salmonella spp., and Yersina spp. None of these bacteria was found. Our data suggest that the tourism industry so far has achieved its goal of not introducing pathogens into the Antarctic region. There is, however, an urgent need to further investigate the situation in areas closer to permanent Antarctic settlements.

Risk factors for colonization with extended-spectrum beta-lactamase producing Enterobacteriaceae in healthcare students on clinical assignment abroad: A prospective study.

BACKGROUND: The increase of antibiotic resistance in clinically important bacteria is a worldwide threat, especially in healthcare environments. International travel is a risk factor for gut colonization with extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE). The risk for healthcare students of being colonized with ESBL-PE when participating in patient-related work abroad has not been previously investigated. METHODS: Swedish healthcare students travelling for pre-clinical and clinical courses outside Scandinavia submitted faecal samples and survey data before and after travel. The faecal samples were screened for ESBL-PE and carbapenemase-producing Enterobacteriaceae (CPE). Screening results and survey data were analysed to identify risk factors for colonization. RESULTS: In the 99 subjects who submitted a full set of samples, 35% were colonized with a new ESBL-PE strain during travel. No CPE was found. The most important risk factor for ESBL-PE colonization was travel destination, and the highest colonization rate was found in the South-East Asia region. Antibiotic treatment during travel was an independent risk factor for ESBL-PE colonization but patient-related work was not significantly associated with an increased risk. CONCLUSIONS: Patient-related work abroad was not a risk factor for ESBL-PE suggesting that transmission from patients is uncommon. Pre-travel advice on avoiding unnecessary antibiotic treatment during travel is recommended.

Salmonella Amager, Campylobacter jejuni, and urease-positive thermophilic Campylobacter found in free-flying peregrine falcons (Falco peregrinus) in Sweden.

Rare species with small population sizes are vulnerable to perturbations such as disease, inbreeding, or random events. The threat arising from microbial pathogens could be large and other species could act as reservoirs for pathogens. We report finding three enteric bacterial species, Salmonella Amager, Campylobacter jejuni, and urease-positive thermophilic Campylobacter, in nestling free-flying peregrine falcons (Falco peregrinus) in Sweden in 2000. Campylobacter jejuni isolates exhibited marked genetic similarities to an isolate from a human, providing a possible association between a human-associated strain of this bacterium and peregrine falcons.

Characterization of a pore-forming cytotoxin expressed by Salmonella enterica serovars typhi and paratyphi A.

Cytolysin A (ClyA) is a pore-forming cytotoxic protein encoded by the clyA gene that has been characterized so far only in Escherichia coli. Using DNA sequence analysis and PCR, we established that clyA is conserved in the human-specific typhoid Salmonella enterica serovars Typhi and Paratyphi A and that the entire clyA gene locus is absent in many other S. enterica serovars, including Typhimurium. The gene products, designated ClyA(STy) and ClyA(SPa), show >/=90% amino acid identity to E. coli cytolysin A, ClyA(EC), and they are immunogenically related. The Salmonella proteins showed a pore-forming activity and are hence functional homologues to ClyA(EC). The chromosomal clyA(STy) gene locus was expressed at detectable levels in the serovar Typhi strains S2369/96 and S1112/97. Furthermore, in the serovar Typhi vaccine strain Ty21a, expression of clyA(STy) reached phenotypic levels, as detected on blood agar plates. The hemolytic phenotype was abolished by the introduction of an in-frame deletion in the clyA(STy) chromosomal locus of Ty21a. Transcomplementation of the mutant with a cloned clyA(STy) gene restored the hemolytic phenotype. To our knowledge, Ty21a is the first reported phenotypically hemolytic Salmonella strain in which the genetic determinant has been identified.