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- Andersson, Sarah, et al.
(författare)
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Malmbanan Diaries
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This booklet is a report for a case study visit during four day field trip, a group of nine PhD students and their supervisors – all part of the National Research School for Architecture and Planning in the Urban Landscape, APULA – set out to explore what may be considered the outback of Western Europe’s conurbations, the transnational region of Kiruna -Narvik.Both “remote” and “resourceful”, “threatened” and “thriving” (equally relative notions), this region seemed to offer possibilities to reflect upon many of the current tendencies influencing contemporary planning practice and research.
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| 2. |
- Dwibedi, Chinmay Kumar, et al.
(författare)
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Biological amplification of low frequency mutations unravels laboratory culture history of the bio-threat agent Francisella tularensis
- 2020
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Ingår i: Forensic Science International. - : Elsevier. - 1872-4973 .- 1878-0326. ; 45
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Tidskriftsartikel (refereegranskat)abstract
- Challenges of investigating a suspected bio attack include establishing if microorganisms have been cultured to produce attack material and to identify their source. Addressing both issues, we have investigated genetic variations that emerge during laboratory culturing of the bacterial pathogen Francisella tularensis. Key aims were to identify genetic variations that are characteristic of laboratory culturing and explore the possibility of using biological amplification to identify genetic variation present at exceedingly low frequencies in a source sample. We used parallel serial passage experiments and high-throughput sequencing of F. tularensis to explore the genetic variation. We found that during early laboratory culture passages of F. tularensis, gene duplications emerged in the pathogen genome followed by single-nucleotide polymorphisms in genes for bacterial capsule synthesis. Based on a biological enrichment scheme and the use of high-throughput sequencing, we identified genetic variation that likely pre-existed in a source sample. The results support that capsule synthesis gene mutations are common during laboratory culture, and that a biological amplification strategy is useful for linking a F. tularensis sample to a specific laboratory variant among many highly similar variants.
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| 7. |
- Rutgersson, Carolin, et al.
(författare)
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Fluoroquinolones and qnr genes in sediment, water, soil, and human fecal flora in an environment polluted by manufacturing discharges
- 2014
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 48:14, s. 7825-7832
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Tidskriftsartikel (refereegranskat)abstract
- There is increasing concern that environmental antibiotic pollution promotes transfer of resistance genes to the human microbiota. Here, fluoroquinolone-polluted river sediment, well water, irrigated farmland, and human fecal flora of local villagers within a pharmaceutical industrial region in India were analyzed for quinolone resistance (qnr) genes by quantitative PCR. Similar samples from Indian villages farther away from industrial areas, as well as fecal samples from Swedish study participants and river sediment from Sweden, were included for comparison. Fluoroquinolones were detected by MS/MS in well water and soil from all villages located within three km from industrially polluted waterways. Quinolone resistance genes were detected in 42% of well water, 7% of soil samples and in 100% and 18% of Indian and Swedish river sediments, respectively. High antibiotic concentrations in Indian sediment coincided with high abundances of qnr, whereas lower fluoroquinolone levels in well water and soil did not. We could not find support for an enrichment of qnr in fecal samples from people living in the fluoroquinolone-contaminated villages. However, as qnr was detected in 91% of all Indian fecal samples (24% of the Swedish) it suggests that the spread of qnr between people is currently a dominating transmission route.
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| 8. |
- Rutgersson, Carolin, 1983, et al.
(författare)
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Fluoroquinolones and qnr genes in sediment, well water, soil and human fecal flora in an Indian environment polluted by drug manufacturing
- 2014
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 48:14
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Tidskriftsartikel (refereegranskat)abstract
- There is increasing concern that environmental antibiotic pollution promotes transfer of resistance genes to the human microbiota. Here, fluoroquinolone-polluted river sediment, well water, irrigated farmland, and human fecal flora of local villagers within a pharmaceutical industrial region in India were analyzed for quinolone resistance (qnr) genes by quantitative PCR. Similar samples from Indian villages farther away from industrial areas, as well as fecal samples from Swedish study participants and river sediment from Sweden, were included for comparison. Fluoroquinolones were detected by MS/MS in well water and soil from all villages located within three km from industrially polluted waterways. Quinolone resistance genes were detected in 42% of well water, 7% of soil samples and in 100% and 18% of Indian and Swedish river sediments, respectively. High antibiotic concentrations in Indian sediment coincided with high abundances of qnr, whereas lower fluoroquinolone levels in well water and soil did not. We could not find support for an enrichment of qnr in fecal samples from people living in the fluoroquinolone-contaminated villages. However, as qnr was detected in 91% of all Indian fecal samples (24% of the Swedish) it suggests that the spread of qnr between people is currently a dominating transmission route.
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| 9. |
- Ahlinder, Jon, et al.
(författare)
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Increased knowledge of Francisella genus diversity highlights the benefits of optimised DNA-based assays
- 2012
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Ingår i: BMC Microbiology. - : Springer Science and Business Media LLC. - 1471-2180. ; 12, s. 220-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Recent advances in sequencing technologies offer promising tools for generating large numbers of genomes, larger typing databases and improved mapping of environmental bacterial diversity. However, DNA-based methods for the detection of Francisella were developed with limited knowledge about genetic diversity. This, together with the high sequence identity between several Francisella species, means there is a high risk of false identification and detection of the highly virulent pathogen Francisella tularensis. Moreover, phylogenetic reconstructions using single or limited numbers of marker sequences often result in incorrect tree topologies and inferred evolutionary distances. The recent growth in publicly accessible whole-genome sequences now allows evaluation of published genetic markers to determine optimal combinations of markers that minimise both time and laboratory costs. Results: In the present study, we evaluated 38 previously published DNA markers and the corresponding PCR primers against 42 genomes representing the currently known diversity of the genus Francisella. The results highlight that PCR assays for Francisella tularensis are often complicated by low specificity, resulting in a high probability of false positives. A method to select a set of one to seven markers for obtaining optimal phylogenetic resolution or diagnostic accuracy is presented. Conclusions: Current multiple-locus sequence-typing systems and detection assays of Francisella, could be improved by redesigning some of the primers and reselecting typing markers. The use of only a few optimally selected sequence-typing markers allows construction of phylogenetic topologies with almost the same accuracy as topologies based on whole-genome sequences.
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| 10. |
- Bengtsson-Palme, Johan, 1985, et al.
(författare)
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The human gut microbiome as a transporter of antibiotic resistance genes between continents
- 2015
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Ingår i: Antimicrobial Agents and Chemotherapy. - 0066-4804 .- 1098-6596. ; 59:10, s. 6551-6560
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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