| 1. |
- Karlsson, Roger, 1975, et al.
(författare)
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Discovery of Species-unique Peptide Biomarkers of Bacterial Pathogens by Tandem Mass Spectrometry-based Proteotyping
- 2020
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Ingår i: Molecular & Cellular Proteomics. - 1535-9476 .- 1535-9484. ; 19:3, s. 518-528
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Tidskriftsartikel (refereegranskat)abstract
- Mass spectrometry (MS) and proteomics offer comprehensive characterization and identification of microorganisms and discovery of protein biomarkers that are applicable for diagnostics of infectious diseases. The use of biomarkers for diagnostics is widely applied in the clinic and the use of peptide biomarkers is increasingly being investigated for applications in the clinical laboratory. Respiratory-tract infections are a predominant cause for medical treatment, although, clinical assessments and standard clinical laboratory protocols are time-consuming and often inadequate for reliable diagnoses. Novel methods, preferably applied directly to clinical samples, excluding cultivation steps, are needed to improve diagnostics of infectious diseases, provide adequate treatment and reduce the use of antibiotics and associated development of antibiotic resistance. This study applied nano-liquid chromatography (LC) coupled with tandem MS, with a bioinformatics pipeline and an in-house database of curated high-quality reference genome sequences to identify species-unique peptides as potential biomarkers for four bacterial pathogens commonly found in respiratory tract infections (RTIs): Staphylococcus aureus; Moraxella catarrhalis; Haemophilus influenzae and Streptococcus pneumoniae. The species-unique peptides were initially identified in pure cultures of bacterial reference strains, reflecting the genomic variation in the four species and, furthermore, in clinical respiratory tract samples, without prior cultivation, elucidating proteins expressed in clinical conditions of infection. For each of the four bacterial pathogens, the peptide biomarker candidates most predominantly found in clinical samples, are presented. Data are available via ProteomeXchange with identifier PXD014522. As proof-of-principle, the most promising species-unique peptides were applied in targeted tandem MS-analyses of clinical samples and their relevance for identifications of the pathogens, i.e. proteotyping, was validated, thus demonstrating their potential as peptide biomarker candidates for diagnostics of infectious diseases.
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| 2. |
- Myhrman, Sofia, et al.
(författare)
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Unexpected details regarding nosocomial transmission revealed by whole-genome sequencing of SARS-CoV-2
- 2022
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Ingår i: Infection Control and Hospital Epidemiology. - : Cambridge University Press (CUP). - 0899-823X .- 1559-6834. ; 43:10, s. 1403-1407
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Effective infection prevention and control (IPC) measures are key for protecting patients from nosocomial infections and require knowledge of transmission mechanisms in different settings. We performed a detailed outbreak analysis of the transmission and outcome of coronavirus disease 2019 (COVID-19) in a geriatric ward by combining whole-genome sequencing (WGS) with epidemiological data. Design: Retrospective cohort study. Setting: Tertiary care hospital. Participants: Patients and healthcare workers (HCWs) from the ward with a nasopharyngeal sample (NPS) positive for SARS-CoV-2 RNA during the outbreak period. Methods: Patient data regarding clinical characteristics, exposure and outcome were collected retrospectively from medical records. Stored NPS from 32 patients and 15 HCWs were selected for WGS and phylogenetic analysis. Results: Median patient age was 84 years and 17/32 (53%) were male. Fourteen patients (44%) died within 30 days after sampling. Viral load was significantly higher among the deceased. WGS was successful in 28/32 (88%) patient samples and 14/15 (93%) HCW samples. Three separate viral clades were identified, whereof one clade and two subclades among both patient and HCW samples. Integrated epidemiological and genetic analysis revealed six probable transmission events between patients and supported hospital-acquired COVID-19 in 25/32 patients. Conclusion: WGS provided a deep insight into the outbreak dynamics and true extent of nosocomial COVID-19. The extensive transmission between patients and HCWs indicated that current IPC measures were insufficient. We suggest increased use of WGS in outbreak investigations for identification of otherwise unknown transmission links and evaluation of IPC measures.
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| 3. |
- Olausson, Josefin, 1983, et al.
(författare)
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Optimization of cerebrospinal fluid microbial DNA metagenomic sequencing diagnostics
- 2022
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Infection in the central nervous system is a severe condition associated with high morbidity and mortality. Despite ample testing, the majority of encephalitis and meningitis cases remain undiagnosed. Metagenomic sequencing of cerebrospinal fluid has emerged as an unbiased approach to identify rare microbes and novel pathogens. However, several major hurdles remain, including establishment of individual limits of detection, removal of false positives and implementation of universal controls. Twenty-one cerebrospinal fluid samples, in which a known pathogen had been positively identified by available clinical techniques, were subjected to metagenomic DNA sequencing. Fourteen samples contained minute levels of Epstein-Barr virus. The detection threshold for each sample was calculated by using the total leukocyte content in the sample and environmental contaminants found in the bioinformatic classifiers. Virus sequences were detected in all ten samples, in which more than one read was expected according to the calculations. Conversely, no viral reads were detected in seven out of eight samples, in which less than one read was expected according to the calculations. False positive pathogens of computational or environmental origin were readily identified, by using a commonly available cell control. For bacteria, additional filters including a comparison between classifiers removed the remaining false positives and alleviated pathogen identification. Here we show a generalizable method for identification of pathogen species using DNA metagenomic sequencing. The choice of bioinformatic method mainly affected the efficiency of pathogen identification, but not the sensitivity of detection. Identification of pathogens requires multiple filtering steps including read distribution, sequence diversity and complementary verification of pathogen reads.
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| 4. |
- Ringlander, Johan, et al.
(författare)
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Recurrent and persistent infection with SARS-CoV-2-epidemiological data and case reports from Western Sweden, 2020
- 2021
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Ingår i: Infectious Diseases. - : Informa UK Limited. - 2374-4235 .- 2374-4243. ; 53:12, s. 900-907
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Tidskriftsartikel (refereegranskat)abstract
- Background Reinfections with SARS-CoV-2 have been reported and most cases were classified as mild. Reports of persistent infection with SARS-CoV-2 are rare. Aim To investigate the frequency of recurrent and persistent infection with SARS-CoV-2. Methods Possible cases of reinfection and persistent infection were retrospectively identified in a database of 59,998 patients. Deep sequencing of SARS-CoV-2 genomes was performed. Results We report the first case of COVID-19 reinfection in Sweden and three cases of infection with persistence over several months. The rate of sequencing-verified reinfection was 0.02% (one patient out of 6014 patients testing positive during the period). Conclusions The reinfected patient had mild symptoms during the second episode, which might reflect partial immunity. The frequency of reinfection during the first wave of the pandemic in western Sweden was very low. Our results indicate that elderly with a putative reinfection more likely have persistent COVID-19.
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| 5. |
- Salva-Serra, Francisco, 1989, et al.
(författare)
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Comparative genomics of Stutzerimonas balearica (Pseudomonas balearica): diversity, habitats, and biodegradation of aromatic compounds
- 2023
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Ingår i: Frontiers in Microbiology. - 1664-302X. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Stutzerimonas balearica (Pseudomonas balearica) has been found principally in oil-polluted environments. The capability of S. balearica to thrive from the degradation of pollutant compounds makes it a species of interest for potential bioremediation applications. However, little has been reported about the diversity of S. balearica. In this study, genome sequences of S. balearica strains from different origins were analyzed, revealing that it is a diverse species with an open pan-genome that will continue revealing new genes and functionalities as the genomes of more strains are sequenced. The nucleotide signatures and intra- and inter-species variation of the 16S rRNA genes of S. balearica were reevaluated. A strategy of screening 16S rRNA gene sequences in public databases enabled the detection of 158 additional strains, of which only 23% were described as S. balearica. The species was detected from a wide range of environments, although mostly from aquatic and polluted environments, predominantly related to petroleum oil. Genomic and phenotypic analyses confirmed that S. balearica possesses varied inherent capabilities for aromatic compounds degradation. This study increases the knowledge of the biology and diversity of S. balearica and will serve as a basis for future work with the species.
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| 6. |
- Salvà-Serra, Francisco, 1989, et al.
(författare)
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Complete genome sequences of Streptococcus pyogenes type strain reveal 100%-match between PacBio-solo and Illumina-Oxford Nanopore hybrid assemblies
- 2020
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- We present the first complete, closed genome sequences of Streptococcus pyogenes strains NCTC 8198(T) and CCUG 4207(T), the type strain of the type species of the genus Streptococcus and an important human pathogen that causes a wide range of infectious diseases. S. pyogenes NCTC 8198(T) and CCUG 4207(T) are derived from deposit of the same strain at two different culture collections. NCTC 8198(T) was sequenced, using a PacBio platform; the genome sequence was assembled de novo, using HGAP. CCUG 4207(T) was sequenced and a de novo hybrid assembly was generated, using SPAdes, combining Illumina and Oxford Nanopore sequence reads. Both strategies yielded closed genome sequences of 1,914,862 bp, identical in length and sequence identity. Combining short-read Illumina and long-read Oxford Nanopore sequence data circumvented the expected error rate of the nanopore sequencing technology, producing a genome sequence indistinguishable to the one determined with PacBio. Sequence analyses revealed five prophage regions, a CRISPR-Cas system, numerous virulence factors and no relevant antibiotic resistance genes. These two complete genome sequences of the type strain of S. pyogenes will effectively serve as valuable taxonomic and genomic references for infectious disease diagnostics, as well as references for future studies and applications within the genus Streptococcus.
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