| 1. |
- Tång Hallbäck, Erika, 1973, et al.
(författare)
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Outbreak of OXA-48-producing Enterobacteriaceae in a neonatal intensive care unit in Western Sweden
- 2023
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Ingår i: European Journal of Clinical Microbiology and Infectious Diseases. - : Springer Science and Business Media LLC. - 1435-4373 .- 0934-9723. ; 42:5, s. 597-605
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Tidskriftsartikel (refereegranskat)abstract
- In 2015, an outbreak caused by OXA-48-producing Enterobacteriaceae affected a neonatal intensive care unit at a Swedish University Hospital. The aim was to explore the transmission of OXA-48-producing strains between infants and the transfer of resistance plasmids between strains during the outbreak. Twenty-four outbreak isolates from ten suspected cases were whole-genome sequenced. A complete assembly was created for the index isolate (Enterobacter cloacae) and used as a mapping reference to detect its plasmids in the remaining isolates (17 Klebsiella pneumoniae, 4 Klebsiella aerogenes, and 2 Escherichia coli). Strain typing was performed using core genome MLST and SNP analysis. As judged from sequencing and clinical epidemiological data, the outbreak involved nine cases (two developed sepsis) and four OXA-48-producing strains: E. cloacae ST1584 (index case), K. pneumoniae ST25 (eight cases), K. aerogenes ST93 (two cases), and E. coli ST453 (2 cases). Two plasmids from the index strain, pEclA2 and pEclA4, carrying blaOXA48 and blaCMY-4, respectively, were traced to all K. pneumoniae ST25 isolates. Klebsiella aerogenes ST93 and E. coli ST453 harboured either only pEclA2, or both pEclA2 and pEclA4. One suspected case harbouring OXA-162-producing K. pneumoniae ST37 could be excluded from the outbreak. Once initiated by an E. cloacae strain, the outbreak was caused by the dissemination of a K. pneumoniae ST25 strain and involved inter-species horizontal transfer of two resistance plasmids, one of which carried blaOXA-48. To our knowledge, this is the first description of an outbreak of OXA-48-producing Enterobacteriaceae in a neonatal setting in northern Europe.
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| 2. |
- Hammarström, Helena, et al.
(författare)
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Fungal Tracheobronchitis in Lung Transplant Recipients : Incidence and Utility of Diagnostic Markers
- 2023
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Ingår i: Journal of Fungi. - : MDPI AG. - 2309-608X. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Fungal tracheobronchitis caused by Aspergillus and Candida spp. is a recognized complication after lung transplantation, but knowledge of the incidence of Candida tracheobronchitis is lacking. The diagnosis relies on fungal cultures in bronchoalveolar lavage fluid (BALF), but cultures have low specificity. We aimed to evaluate the one-year incidence of fungal tracheobronchitis after lung transplantation and to assess the utility of diagnostic markers in serum and BALF to discriminate fungal tracheobronchitis from colonization. Ninety-seven consecutively included adult lung-transplant recipients were prospectively followed. BALF and serum samples were collected at 1, 3 and 12 months after transplantation and analyzed for betaglucan (serum and BALF), neutrophils (BALF) and galactomannan (BALF). Fungal tracheobronchitis was defined according to consensus criteria, modified to include Candida as a mycologic criterion. The cumulative one-year incidence of Candida and Aspergillus tracheobronchitis was 23% and 16%, respectively. Neutrophils of >75% of total leukocytes in BALF had 92% specificity for Candida tracheobronchitis. The area under the ROC curves for betaglucan and galactomannan in BALF to discriminate Aspergillus tracheobronchitis from colonization or no fungal infection were high (0.86 (p < 0.0001) and 0.93 (p < 0.0001), respectively). To conclude, the one-year incidence of fungal tracheobronchitis after lung transplantation was high and dominated by Candida spp. Diagnostic markers in BALF could be useful to discriminate fungal colonization from tracheobronchitis.
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| 3. |
- Halwachs, Bettina, et al.
(författare)
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Critical Issues in mycobiota analysis
- 2017
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Ingår i: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Fungi constitute an important part of the human microbiota and they play a significant role for health and disease development. Advancements made in the culture-independent analysis of microbial communities have broadened our understanding of the mycobiota, however, microbiota analysis tools have been mainly developed for bacteria (e.g., targeting the 16S rRNA gene) and they often fall short if applied to fungal marker-gene based investigations (i.e., internal transcribed spacers, ITS). In the current paper we discuss all major steps of a fungal amplicon analysis starting with DNA extraction from specimens up to bioinformatics analyses of next-generation sequencing data. Specific points are discussed at each step and special emphasis is placed on the bioinformatics challenges emerging during operational taxonomic unit (OTU) picking, a critical step in mycobiota analysis. By using an in silico ITS1 mock community we demonstrate that standard analysis pipelines fall short if used with default settings showing erroneous fungal community representations. We highlight that switching OTU picking to a closed reference approach greatly enhances performance. Finally, recommendations are given on how to perform ITS based mycobiota analysis with the currently available measures.
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| 4. |
- Zamora, Leydis, et al.
(författare)
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Chryseobacterium viscerum sp. nov., isolated from diseased fish.
- 2012
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Ingår i: International journal of systematic and evolutionary microbiology. - : Microbiology Society. - 1466-5034 .- 1466-5026. ; 62:Pt12, s. 2934-40
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Tidskriftsartikel (refereegranskat)abstract
- A taxonomic study was carried out on five Gram-staining-negative, catalase- and oxidase-positive, rod-shaped bacteria isolated from the gill and liver of five diseased rainbow trout. On the basis of 16S rRNA gene sequence analysis, the trout isolates belonged to the genus Chryseobacterium, exhibiting the highest similarity with Chryseobacterium oncorhynchi 701B-08T (98.9 % sequence similarity), C. ureilyticum F-Fue-04IIIaaaaT (98.6 %), C. indologenes ATCC 29897T (98.3 %), C. jejuense JS17-8T (98.1 %) and C. gleum ATCC 35910T (98.1 %). DNA-DNA hybridization values were 99-100 % among the five isolates and 21 and 57 % between strain 687B-08T, selected as a representative isolate, and the type strains of Chryseobacterium oncorhynchi 701B-08T, C. ureilyticum F-Fue-04IIIaaaaT and other phylogenetic related Chryseobacterium species. The predominant respiratory quinone of strain 687B-08T was MK-6 and the major cellular fatty acids were iso-C15:0, iso-C17:1 ω9c, iso-C17:0 3-OH and C16:1 ω6c. The G+C content of the chromosomal DNA of strain 687B-08T was 38.6 mol%. Based on the phenotypic and genotypic features, the novel bacteria isolated from rainbow trout were significantly different from the related Chryseobacterium species and, therefore, they were identified as representing a novel species of the genus Chryseobacterium, for which the name Chryseobacterium viscerum sp. nov. is proposed. The type strain is 687B-08T (= CECT 7793T = CCUG 60103T).
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| 5. |
- Müller, Vilhelm, 1990, et al.
(författare)
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Rapid Tracing of Resistance Plasmids in a Nosocomial Outbreak Using Optical DNA Mapping
- 2016
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Ingår i: Acs Infectious Diseases. - : American Chemical Society (ACS). - 2373-8227. ; 2:5, s. 322-328
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Tidskriftsartikel (refereegranskat)abstract
- Resistance to life-saving antibiotics increases rapidly worldwide, and multiresistant bacteria have become a global threat to human health. Presently, the most serious threat is the increasing spread of Enterobacteriaceae carrying genes coding for extended spectrum beta-lactamases (ESBL) and carbapenemases on highly mobile plasmids. We here demonstrate how optical DNA maps of single plasmids can be used as fingerprints to trace plasmids, for example, during resistance outbreaks. We use the assay to demonstrate a potential transmission route of an ESBL-carrying plasmid between bacterial strains/species and between patients, during a polyclonal outbreak at a neonatal ward at Sahlgrenska University Hospital (Gothenburg, Sweden). Our results demonstrate that optical DNA mapping is an easy and rapid method for detecting the spread of plasmids mediating resistance. With the increasing prevalence of multiresistant bacteria, diagnostic tools that can aid in solving ongoing routes of transmission, in particular in hospital settings, will be of paramount importance.
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| 6. |
- Svensson, Sara L, et al.
(författare)
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Midkine and Pleiotrophin have bactericidal properties : preserved antibacterial activity in a family of Heparin-binding growth factors during evolution
- 2010
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 285:21, s. 16105-16115
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Tidskriftsartikel (refereegranskat)abstract
- Antibacterial peptides of the innate immune system combat pathogenic microbes, but often have additional roles in promoting inflammation and as growth factors during tissue repair. Midkine (MK) and pleiotrophin (PTN) are the only two members of a family of heparin-binding growth factors. They show restricted expression during embryogenesis and are up-regulated in neoplasia. In addition, MK shows constitutive and inflammation-dependent expression in some non-transformed tissues of the adult. In the present study, we show that both MK and PTN display strong antibacterial activity, present at physiological salt concentrations. Electron microscopy of bacteria and experiments using artificial lipid bilayers suggest that MK and PTN exert their antibacterial action via a membrane disruption mechanism. The predicted structure of PTN, employing the previously solved MK structure as a template, indicates that both molecules consist of two domains, each containing three antiparallel beta-sheets. The antibacterial activity was mapped to the unordered C-terminal tails of both molecules and the last beta-sheets of the N-terminals. Analysis of the highly conserved MK and PTN orthologues from the amphibian Xenopus laevis and the fish Danio rerio suggests that they also harbor antibacterial activity in the corresponding domains. In support of an evolutionary conserved function it was found that the more distant orthologue, insect Miple2 from Drosophila melanogaster, also displays strong antibacterial activity. Taken together, the findings suggest that MK and PTN, in addition to their earlier described activities, may have previously unrealized important roles as innate antibiotics.
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| 7. |
- Gustafsson, Mika, et al.
(författare)
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A validated gene regulatory network and GWAS identifies early regulators of T cell-associated diseases
- 2015
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Ingår i: Science Translational Medicine. - : AMER ASSOC ADVANCEMENT SCIENCE. - 1946-6234 .- 1946-6242. ; 7:313
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Tidskriftsartikel (refereegranskat)abstract
- Early regulators of disease may increase understanding of disease mechanisms and serve as markers for presymptomatic diagnosis and treatment. However, early regulators are difficult to identify because patients generally present after they are symptomatic. We hypothesized that early regulators of T cell-associated diseases could be found by identifying upstream transcription factors (TFs) in T cell differentiation and by prioritizing hub TFs that were enriched for disease-associated polymorphisms. A gene regulatory network (GRN) was constructed by time series profiling of the transcriptomes and methylomes of human CD4(+) T cells during in vitro differentiation into four helper T cell lineages, in combination with sequence-based TF binding predictions. The TFs GATA3, MAF, and MYB were identified as early regulators and validated by ChIP-seq (chromatin immunoprecipitation sequencing) and small interfering RNA knockdowns. Differential mRNA expression of the TFs and their targets in T cell-associated diseases supports their clinical relevance. To directly test if the TFs were altered early in disease, T cells from patients with two T cell-mediated diseases, multiple sclerosis and seasonal allergic rhinitis, were analyzed. Strikingly, the TFs were differentially expressed during asymptomatic stages of both diseases, whereas their targets showed altered expression during symptomatic stages. This analytical strategy to identify early regulators of disease by combining GRNs with genome-wide association studies may be generally applicable for functional and clinical studies of early disease development.
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| 8. |
- Labbé, Lisa Sandelin, et al.
(författare)
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Candidatus Neoehrlichia mikurensis in Ticks from Migrating Birds in Sweden
- 2015
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:7
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Tidskriftsartikel (refereegranskat)abstract
- Candidatus Neoehrlichia mikurensis (CNM; family Anaplasmataceae) was recently recognized as a potential tick-borne human pathogen. The presence of CNM in mammals, in host-seeking Ixodes ticks and in ticks attached to mammals and birds has been reported recently. We investigated the presence of CNM in ornithophagous ticks from migrating birds. A total of 1,150 ticks (582 nymphs, 548 larvae, 18 undetermined ticks and two adult females) collected from 5,365 birds captured in south-eastern Sweden was screened for CNM by molecular methods. The birds represented 65 different species, of which 35 species were infested with one or more ticks. Based on a combination of morphological and molecular species identification, the majority of the ticks were identified as Ixodes ricinus. Samples were initially screened by real-time PCR targeting the CNM 16S rRNA gene, and confirmed by a second real-time PCR targeting the groEL gene. For positive samples, a 1260 base pair fragment of the 16S rRNA gene was sequenced. Based upon bacterial gene sequence identification, 2.1% (24/1150) of the analysed samples were CNM-positive. Twenty-two out of 24 CNM-positive ticks were molecularly identified as I. ricinus nymphs, and the remaining two were identified as I. ricinus based on morphology. The overall CNM prevalence in I. ricinus nymphs was 4.2%. None of the 548 tested larvae was positive. CNM-positive ticks were collected from 10 different bird species. The highest CNM-prevalences were recorded in nymphs collected from common redpoll (Carduelis flammea, 3/7), thrush nightingale (Luscinia luscinia, 2/29) and dunnock (Prunella modularis, 1/17). The 16S rRNA sequences obtained in this study were all identical to each other and to three previously reported European strains, two of which were obtained from humans. It is concluded that ornithophagous ticks may be infected with CNM and that birds most likely can disperse CNM-infected ticks over large geographical areas.
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| 9. |
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| 10. |
- Wallmenius, Katarina, et al.
(författare)
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Spotted fever Rickettsia species in Hyalomma and Ixodes ticks infesting migratory birds in the European Mediterranean area
- 2014
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Ingår i: Parasites & Vectors. - : Springer Science and Business Media LLC. - 1756-3305. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Background: A few billion birds migrate annually between their breeding grounds in Europe and their wintering grounds in Africa. Many bird species are tick-infested, and as a result of their innate migratory behavior, they contribute significantly to the geographic distribution of pathogens, including spotted fever rickettsiae. The aim of the present study was to characterize, in samples from two consecutive years, the potential role of migrant birds captured in Europe as disseminators of Rickettsia-infected ticks. Methods: Ticks were collected from a total of 14,789 birds during their seasonal migration northwards in spring 2009 and 2010 at bird observatories on two Mediterranean islands: Capri and Antikythira. All ticks were subjected to RNA extraction followed by cDNA synthesis and individually assayed with a real-time PCR targeting the citrate synthase (gltA) gene. For species identification of Rickettsia, multiple genes were sequenced. Results: Three hundred and ninety-eight (2.7%) of all captured birds were tick-infested; some birds carried more than one tick. A total number of 734 ticks were analysed of which 353 +/- 1 (48%) were Rickettsia-positive; 96% were infected with Rickettsia aeschlimannii and 4% with Rickettsia africae or unidentified Rickettsia species. The predominant tick taxon, Hyalomma marginatum sensu lato constituted 90% (n = 658) of the ticks collected. The remaining ticks were Ixodes frontalis, Amblyomma sp., Haemaphysalis sp., Rhipicephalus sp. and unidentified ixodids. Most ticks were nymphs (66%) followed by larvae (27%) and adult female ticks (0.5%). The majority (65%) of ticks was engorged and nearly all ticks contained visible blood. Conclusions: Migratory birds appear to have a great impact on the dissemination of Rickettsia-infected ticks, some of which may originate from distant locations. The potential ecological, medical and veterinary implications of such Rickettsia infections need further examination.
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