| 1. |
- Woksepp, Hanna, et al.
(författare)
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Evaluation of High-Resolution Melting Curve Analysis of Ligation-Mediated Real-Time PCR, a Rapid Method for Epidemiological Typing of ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter Species) Pathogens
- 2014
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Ingår i: Journal of Clinical Microbiology. - : American Society for Microbiology. - 0095-1137 .- 1098-660X. ; 52:12, s. 4339-4342
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Tidskriftsartikel (refereegranskat)abstract
- A single-tube method, ligation-mediated real-time PCR high-resolution melt analysis (LMqPCR HRMA), was modified for the rapid typing of Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp. (ESKAPE) pathogens. A 97% agreement (60/62 isolates) was achieved in comparison to pulsed-field gel electrophoresis (PFGE) results, which indicates that LMqPCR HRMA is a rapid and accurate screening tool for monitoring nosocomial outbreaks.
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| 2. |
- Ahlstrom, Christina A. A., et al.
(författare)
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Exchange of Carbapenem-Resistant Escherichia coli Sequence Type 38 Intercontinentally and among Wild Bird, Human, and Environmental Niches
- 2023
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Ingår i: Applied and Environmental Microbiology. - : American Society for Microbiology. - 0099-2240 .- 1098-5336. ; 89:6
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Tidskriftsartikel (refereegranskat)abstract
- Carbapenem-resistant bacteria are a threat to public health globally and have been found in the environment as well as the clinic. Some bacterial clones are associated with carbapenem resistance genes, such as Escherichia coli sequence type 38 (ST38) and the carbapenemase gene bla(OXA-48). Carbapenem-resistant Enterobacteriaceae (CRE) are a global threat to human health and are increasingly being isolated from nonclinical settings. OXA-48-producing Escherichia coli sequence type 38 (ST38) is the most frequently reported CRE type in wild birds and has been detected in gulls or storks in North America, Europe, Asia, and Africa. The epidemiology and evolution of CRE in wildlife and human niches, however, remains unclear. We compared wild bird origin E. coli ST38 genome sequences generated by our research group and publicly available genomic data derived from other hosts and environments to (i) understand the frequency of intercontinental dispersal of E. coli ST38 clones isolated from wild birds, (ii) more thoroughly measure the genomic relatedness of carbapenem-resistant isolates from gulls sampled in Turkey and Alaska, USA, using long-read whole-genome sequencing and assess the spatial dissemination of this clone among different hosts, and (iii) determine whether ST38 isolates from humans, environmental water, and wild birds have different core or accessory genomes (e.g., antimicrobial resistance genes, virulence genes, plasmids) which might elucidate bacterial or gene exchange among niches. Our results suggest that E. coli ST38 strains, including those resistant to carbapenems, are exchanged between humans and wild birds, rather than separately maintained populations within each niche. Furthermore, despite close genetic similarity among OXA-48-producing E. coli ST38 clones from gulls in Alaska and Turkey, intercontinental dispersal of ST38 clones among wild birds is uncommon. Interventions to mitigate the dissemination of antimicrobial resistance throughout the environment (e.g., as exemplified by the acquisition of carbapenem resistance by birds) may be warranted.IMPORTANCE Carbapenem-resistant bacteria are a threat to public health globally and have been found in the environment as well as the clinic. Some bacterial clones are associated with carbapenem resistance genes, such as Escherichia coli sequence type 38 (ST38) and the carbapenemase gene bla(OXA-48). This is the most frequently reported carbapenem-resistant clone in wild birds, though it was unclear if it circulated within wild bird populations or was exchanged among other niches. The results from this study suggest that E. coli ST38 strains, including those resistant to carbapenems, are frequently exchanged among wild birds, humans, and the environment. Carbapenem-resistant E. coli ST38 clones in wild birds are likely acquired from the local environment and do not constitute an independent dissemination pathway within wild bird populations. Management actions aimed at preventing the environmental dissemination and acquisition of antimicrobial resistance by wild birds may be warranted.
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| 3. |
- Ahlstrom, Christina A., et al.
(författare)
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Acquisition and dissemination of cephalosporin-resistant E.coli in migratory birds sampled at an Alaska landfill as inferred through genomic analysis
- 2018
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Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Antimicrobial resistance (AMR) in bacterial pathogens threatens global health, though the spread of AMR bacteria and AMR genes between humans, animals, and the environment is still largely unknown. Here, we investigated the role of wild birds in the epidemiology of AMR Escherichia coli. Using next-generation sequencing, we characterized cephalosporin-resistant E. coli cultured from sympatric gulls and bald eagles inhabiting a landfill habitat in Alaska to identify genetic determinants conferring AMR, explore potential transmission pathways of AMR bacteria and genes at this site, and investigate how their genetic diversity compares to isolates reported in other taxa. We found genetically diverse E. coli isolates with sequence types previously associated with human infections and resistance genes of clinical importance, including blaCTX-M and blaCMY. Identical resistance profiles were observed in genetically unrelated E. coli isolates from both gulls and bald eagles. Conversely, isolates with indistinguishable core-genomes were found to have different resistance profiles. Our findings support complex epidemiological interactions including bacterial strain sharing between gulls and bald eagles and horizontal gene transfer among E. coli harboured by birds. Results suggest that landfills may serve as a source for AMR acquisition and/or maintenance, including bacterial sequence types and AMR genes relevant to human health.
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| 4. |
- Ahlstrom, Christina A., et al.
(författare)
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Early emergence of mcr-1-positive Enterobacteriaceae in gulls from Spain and Portugal
- 2019
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Ingår i: Environmental Microbiology Reports. - : WILEY. - 1758-2229. ; 11:5, s. 669-671
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Tidskriftsartikel (refereegranskat)abstract
- We tested extended-spectrum beta-lactamase producing bacteria from wild gulls (Larus spp.) sampled in 2009 for the presence of mcr-1. We report the detection of mcr-1 and describe genome characteristics of four Escherichia coli and one Klebsiella pneumoniae isolate from Spain and Portugal that also exhibited colistin resistance. Results represent the earliest evidence for colistin-resistant bacteria in European wildlife.
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| 5. |
- Ahlstrom, Christina A., et al.
(författare)
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Environmental antimicrobial resistance gene detection from wild bird habitats using two methods : A commercially available culture-independent qPCR assay and culture of indicator bacteria followed by whole-genome sequencing
- 2023
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Ingår i: Journal of Global Antimicrobial Resistance. - : Elsevier. - 2213-7165 .- 2213-7173. ; 33, s. 186-193
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: A variety of methods have been developed to detect antimicrobial resistance (AMR) in differ-ent environments to better understand the evolution and dissemination of this public health threat. Com-parisons of results generated using different AMR detection methods, such as quantitative PCR (qPCR) and whole-genome sequencing (WGS), are often imperfect, and few studies have analysed samples in parallel to evaluate differences. In this study, we compared bacterial culture and WGS to a culture-independent commercially available qPCR assay to evaluate the concordance between methods and the utility of each in answering research questions regarding the presence and epidemiology of AMR in wild bird habitats.Methods: We first assessed AMR gene detection using qPCR in 45 bacterial isolates from which we had existing WGS data. We then analysed 52 wild bird faecal samples and 9 spatiotemporally collected water samples using culture-independent qPCR and WGS of phenotypically resistant indicator bacterial isolates.Results: Overall concordance was strong between qPCR and WGS of bacterial isolates, although concor-dance differed among antibiotic classes. Analysis of wild bird faecal and water samples revealed that more samples were determined to be positive for AMR via qPCR than via culture and WGS of bacterial isolates, although qPCR did not detect AMR genes in two samples from which phenotypically resistant isolates were found.Conclusions: Both qPCR and culture followed by sequencing may be effective approaches for characteris-ing AMR genes harboured by wild birds, although data streams produced using these different tools may have advantages and disadvantages that should be considered given the application and sample matrix.Published by Elsevier Ltd on behalf of International Society for Antimicrobial Chemotherapy. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )
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| 6. |
- Ahlstrom, Christina A., et al.
(författare)
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Evidence for continental-scale dispersal of antimicrobial resistant bacteria by landfill-foraging gulls
- 2021
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 764, s. 1-10
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Forskningsöversikt (refereegranskat)abstract
- Anthropogenic inputs into the environment may serve as sources of antimicrobial resistant bacteria and alter the ecology and population dynamics of synanthropic wild animals by providing supplemental forage. In this study, we used a combination of phenotypic and genomic approaches to characterize antimicrobial resistant indicator bacteria, animal telemetry to describe host movement patterns, and a novel modeling approach to combine information from these diverse data streams to investigate the acquisition and long-distance dispersal of antimicrobial resistant bacteria by landfill-foraging gulls. Our results provide evidence that gulls acquire antimicrobial resistant bacteria from anthropogenic sources, which they may subsequently disperse across and between continents via migratory movements. Furthermore, we introduce a flexible modeling framework to estimate the relative dispersal risk of antimicrobial resistant bacteria in western North America and adjacent areas within East Asia, which may be adapted to provide information on the risk of dissemination of other organisms and pathogens maintained by wildlife through space and time. Published by Elsevier B.V.
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| 7. |
- Ahlstrom, Christina A., et al.
(författare)
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Genomically diverse carbapenem resistant Enterobacteriaceae from wild birds provide insight into global patterns of spatiotemporal dissemination
- 2022
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 824
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Tidskriftsartikel (refereegranskat)abstract
- Carbapenem resistant Enterobacteriaceae (CRE) are a threat to public health globally, yet the role of the environment in the epidemiology of CRE remains elusive. Given that wild birds can acquire CRE, likely from foraging in anthropogenically impacted areas, and may aid in the maintenance and dissemination of CRE in the environment, a spatiotemporal comparison of isolates from different regions and timepoints may be useful for elucidating epidemiological information. Thus, we characterized the genomic diversity of CRE from fecal samples opportunistically collected from gulls (Larus spp.) inhabiting Alaska (USA), Chile, Spain, Turkey, and Ukraine and from black kites (Milvus migrans) sampled in Pakistan and assessed evidence for spatiotemporal patterns of dissemination. Within and among sampling locations, a high diversity of carbapenemases was found, including Klebsiella pneumoniae carbapenemase (KPC), New Delhi metallo-beta-lactamase (NDM), oxacillinase (OXA), and Verona integron Metallo beta-lactamase (VIM). Although the majority of genomic comparisons among samples did not provide evidence for spatial dissemination, we did find strong evidence for dissemination among Alaska, Spain, and Turkey. We also found strong evidence for temporal dissemination among samples collected in Alaska and Pakistan, though the majority of CRE clones were transitory and were not repeatedly detected among locations where samples were collected longitudinally. Carbapenemase-producing hypervirulent K. pneumoniae was isolated from gulls in Spain and Ukraine and some isolates harbored antimicrobial resistance genes conferring resistance to up to 10 different antibiotic classes, including colistin. Our results are consistent with local acquisition of CRE by wild birds with spatial dissemination influenced by intermediary transmission routes, likely involving humans. Furthermore, our results support the premise that anthropogenicallyassociated wild birds may be good sentinels for understanding the burden of clinically-relevant antimicrobial resistance in the local human population.
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| 8. |
- Ahlstrom, Christina A., et al.
(författare)
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Repeated Detection of Carbapenemase-Producing Escherichia coil in Gulls Inhabiting Alaska
- 2019
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Ingår i: Antimicrobial Agents and Chemotherapy. - : AMER SOC MICROBIOLOGY. - 0066-4804 .- 1098-6596. ; 63:8
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Tidskriftsartikel (refereegranskat)abstract
- Here, we report the first detection of carbapenemase-producing Escherichia coli in Alaska and in wildlife in the United States. Wild bird (gull) feces sampled at three locations in Southcentral Alaska yielded isolates that harbored plasmidencoded bla(kpc-2), or chromosomally encoded bla(OXA-48) and genes associated with antimicrobial resistance to up to eight antibiotic classes.
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| 9. |
- Ahlstrom, Christina A., et al.
(författare)
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Satellite tracking of gulls and genomic characterization of faecal bacteria reveals environmentally mediated acquisition and dispersal of antimicrobial-resistant Escherichia coli on the Kenai Peninsula, Alaska
- 2019
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Ingår i: Molecular Ecology. - : WILEY. - 0962-1083 .- 1365-294X. ; 28:10, s. 2531-2545
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Tidskriftsartikel (refereegranskat)abstract
- Gulls (Larus spp.) have frequently been reported to carry Escherichia coli exhibiting antimicrobial resistance (AMR E. coli); however, the pathways governing the acquisition and dispersal of such bacteria are not well described. We equipped 17 landfill-foraging gulls with satellite transmitters and collected gull faecal samples longitudinally from four locations on the Kenai Peninsula, Alaska to assess: (a) gull attendance and transitions between sites, (b) spatiotemporal prevalence of faecally shed AMR E. coli, and (c) genomic relatedness of AMR E. coli isolates among sites. We also sampled Pacific salmon (Oncorhynchus spp.) harvested as part of personal-use dipnet fisheries at two sites to assess potential contamination with AMR E. coli. Among our study sites, marked gulls most commonly occupied the lower Kenai River (61% of site locations) followed by the Soldotna landfill (11%), lower Kasilof River (5%) and upper Kenai River (<1%). Gulls primarily moved between the Soldotna landfill and the lower Kenai River (94% of transitions among sites), which were also the two locations with the highest prevalence of AMR E. coli. There was relatively high spatial and temporal variability in AMR E. coli prevalence in gull faeces and there was no evidence of contamination on salmon harvested in personal-use fisheries. We identified E. coli sequence types and AMR genes of clinical importance, with some isolates possessing genes associated with resistance to as many as eight antibiotic classes. Our findings suggest that gulls acquire AMR E. coli at habitats with anthropogenic inputs and subsequent movements may represent pathways through which AMR is dispersed.
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| 10. |
- Bhaskaran, Nimesh, et al.
(författare)
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Comparative proteome profiling of MCF10A and 184A1 human breast epithelial cells emphasized involvement of CDK4 and cyclin D3 in cell proliferation
- 2009
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Ingår i: Proteomics Clinical Applications. - : Wiley. - 1862-8354 .- 1862-8346. ; 3:1, s. 68-77
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Tidskriftsartikel (refereegranskat)abstract
- Acquiring high proliferation rate is crucial for carcinogenic transformation of cells. We reporthere proteome profiling of human breast epithelial cells with low (184A1) and high (MCF10A)proliferation rates.We identified 183 proteins in 184A1 and 318 proteins in MCF10A cells. Thesedatasets provide the most comprehensive proteome annotations of 184A1 and MCF10A cells.Proteins were taken for identification from 2-D gels in a systematic and unbiased way. Functionalclustering of the identified proteins showed similarities in distribution of proteins to the samefunctional domains, indicating similarities in proteomes of 184A1 and MCF10A cells. Amongobserved differences in protein expression, we validated correlation of expression of endogenouscyclin-dependent kinase 4 (CDK4), cyclin D3, cdc25B, and p38g with cell proliferation. Furthermore,down-regulation of CDK4 and cyclin D3 with specific siRNA inhibited cell proliferation,which emphasized the role of CDK4 and cyclin D3 in enhancement of cell proliferation rate ofhuman breast epithelial cells.
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