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- Ankarklev, Johan, et al.
(author)
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Common Coinfections of Giardia intestinalis and Helicobacter pylori in Non-Symptomatic Ugandan Children
- 2012
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In: PLOS Neglected Tropical Diseases. - : Public Library of Science (PLoS). - 1935-2735. ; 6:8, s. e1780-
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Journal article (peer-reviewed)abstract
- Background: The protozoan parasite Giardia intestinalis and the pathogenic bacterium Helicobacter pylori are well known for their high prevalences in human hosts worldwide. The prevalence of both organisms is known to peak in densely populated, low resource settings and children are infected early in life. Different Giardia genotypes/assemblages have been associated with different symptoms and H. pylori with induction of cancer. Despite this, not much data are available from sub-Saharan Africa with regards to the prevalence of different G. intestinalis assemblages and their potential association with H. pylori infections.Methodology/Principal Findings: Fecal samples from 427 apparently healthy children, 0-12 years of age, living in urban Kampala, Uganda were analyzed for the presence of H. pylori and G. intestinalis. G. intestinalis was found in 86 (20.1%) out of the children and children age 1<5 years had the highest rates of colonization. H. pylori was found in 189 (44.3%) out of the 427 children and there was a 3-fold higher risk of concomitant G. intestinalis and H. pylori infections compared to non-concomitant G. intestinalis infection, OR = 2.9 (1.7-4.8). No significant association was found in the studied population with regard to the presence of Giardia and gender, type of toilet, source of drinking water or type of housing. A panel of 45 G. intestinalis positive samples was further analyzed using multi-locus genotyping (MLG) on three loci, combined with assemblage-specific analyses. Giardia MLG analysis yielded a total of five assemblage AII, 25 assemblage B, and four mixed assemblage infections. The assemblage B isolates were highly genetically variable but no significant association was found between Giardia assemblage type and H. pylori infection.Conclusions/Significance: This study shows that Giardia assemblage B dominates in children in Kampala, Uganda and that the presence of H. pylori is an associated risk factor for G. intestinalis infection.
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- Gilles, Stefanie, et al.
(author)
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Pollen exposure weakens innate defense against respiratory viruses.
- 2020
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In: Allergy. - : Wiley. - 1398-9995 .- 0105-4538. ; 75:3, s. 576-587
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Journal article (peer-reviewed)abstract
- Hundreds of plant species release their pollen into the air every year during early spring. During that period, pollen allergic as well as non-allergic patients frequently present to doctors with severe respiratory tract infections.To assess whether pollen may interfere with antiviral immunity.We combined data from real life human exposure cohorts, a mouse model and human cell culture to test our hypothesis.Pollen significantly diminished interferon-λ and pro-inflammatory chemokine responses of airway epithelia to rhinovirus and viral mimics and decreased nuclear translocation of interferon regulatory factors. In mice infected with respiratory syncytial virus, co-exposure to pollen caused attenuated antiviral gene expression and increased pulmonary viral titers. In non-allergic human volunteers, nasal symptoms were positively correlated with airborne birch pollen abundance, and nasal birch pollen challenge led to down-regulation of type I and -III interferons in nasal mucosa. In a large patient cohort, numbers of rhinovirus-positive cases were correlated with airborne birch pollen concentrations.The ability of pollen to suppress innate antiviral immunity, independent of allergy, suggests that high-risk population groups should avoid extensive outdoor activities when pollen and respiratory virus seasons coincide.
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- Haars, Jonathan, et al.
(author)
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Prevalence of SARS-CoV-2 Omicron Sublineages and Spike Protein Mutations Conferring Resistance against Monoclonal Antibodies in a Swedish Cohort during 2022–2023
- 2023
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In: Microorganisms. - : MDPI. - 2076-2607. ; 11:10
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Journal article (peer-reviewed)abstract
- Monoclonal antibodies (mAbs) are an important treatment option for COVID-19 caused by SARS-CoV-2, especially in immunosuppressed patients. However, this treatment option can become ineffective due to mutations in the SARS-CoV-2 genome, mainly in the receptor binding domain (RBD) of the spike (S) protein. In the present study, 7950 SARS-CoV-2 positive samples from the Uppsala and Örebro regions of central Sweden, collected between March 2022 and May 2023, were whole-genome sequenced using amplicon-based sequencing methods on Oxford Nanopore GridION, Illumina MiSeq, Illumina HiSeq, or MGI DNBSEQ-G400 instruments. Pango lineages were determined and all single nucleotide polymorphism (SNP) mutations that occurred in these samples were identified. We found that the dominant sublineages changed over time, and mutations conferring resistance to currently available mAbs became common. Notable ones are R346T and K444T mutations in the RBD that confer significant resistance against tixagevimab and cilgavimab mAbs. Further, mutations conferring a high-fold resistance to bebtelovimab, such as the K444T and V445P mutations, were also observed in the samples. This study highlights that resistance mutations have over time rendered currently available mAbs ineffective against SARS-CoV-2 in most patients. Therefore, there is a need for continued surveillance of resistance mutations and the development of new mAbs that target more conserved regions of the RBD.
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- Lindström, Johan, 1984, et al.
(author)
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Assessment of the FilmArray ME panel in 4199 consecutively tested cerebrospinal fluid samples
- 2022
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In: Clinical Microbiology and Infection. - : Elsevier BV. - 1198-743X. ; 28:1, s. 79-84
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Journal article (peer-reviewed)abstract
- Objectives: In central nervous system infections, early and correct management is of utmost importance. Rapid syndromic panel testing can potentially provide valuable guidance. The FilmArray meningitis/encephalitis (ME) panel detects 14 pathogens through multiplex PCR. Our study objectives were to assess its performance compared with established diagnostic procedures, especially real-time quantitative PCR for detection of viruses, and to determine the diagnostic and clinical significance of discrepant results. Methods: All cerebrospinal fluid samples sent for viral diagnostics to our microbiological laboratory over 34 months were analysed with the ME panel and in-house real-time PCR for herpes simplex virus type 1 (HSV-1), HSV-2, varicella zoster virus and enteroviruses. Other pathogens detected by the panel were confirmed by routine diagnostic procedures. Discrepant results were analysed through interpretation of biological and clinical data, and performance data were calculated for individual pathogens. Results: Altogether, 315 pathogens were detected by the ME panel in 4199 cerebrospinal fluid samples (7.5%) and an additional 21 viral targets were identified using real-time PCR. Thirty-four ME panel detections were not confirmed, totalling 55 discrepant results. After discrepancy analysis, 20 false-positive and 21 false-negative ME panel results remained. Performance varied between pathogens. Sensitivity for HSV-1 was calculated at 82.4% (59.0%–93.8%) with three false-negative results. Also noteworthy were 13 false-negative enterovirus and eight false-positive Streptococcus pneumoniae results. Conclusions: Our analysis shows good performance for the ME panel in diagnosing central nervous system infection. The risk of false-negative HSV-1 results, however, warrants additional testing when encephalitis is suspected. Uncertainties in interpretation of enterovirus and S. pneumoniae results represent other limitations. © 2021 The Author(s)
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- Mannsverk, Steinar, et al.
(author)
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SARS-CoV-2 variants of concern and spike protein mutational dynamics in a Swedish cohort during 2021, studied by Nanopore sequencing
- 2022
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In: Virology Journal. - : Springer Nature. - 1743-422X. ; 19
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Journal article (peer-reviewed)abstract
- Background: Since the beginning of the COVID-19 pandemic, new variants of significance to public health have emerged. Consequently, early detection of new mutations and variants through whole-genome sequencing remains crucial to assist health officials in employing appropriate public health measures.Methods: We utilized the ARTIC Network SARS-CoV-2 tiled amplicon approach and Nanopore sequencing to sequence 4,674 COVID-19 positive patient samples from Uppsala County, Sweden, between week 15 and 52 in 2021. Using this data, we mapped the circulating variants of concern (VOC) in the county over time and analysed the Spike (S) protein mutational dynamics in the Delta variant throughout 2021.Results: The distribution of the SARS-CoV-2 VOC matched the national VOC distribution in Sweden, in 2021. In the S protein of the Delta variant, we detected mutations attributable to variants under monitoring and variants of interest (e.g., E484Q, Q613H, Q677H, A222V and Y145H) and future VOC (e.g., T95I and Y144 deletion, which are signature mutations in the Omicron variant). We also frequently detected some less well-described S protein mutations in our Delta sequences, that might play a role in shaping future emerging variants. These include A262S, Q675K, I850L, Q1201H, V1228L and M1237I. Lastly, we observed that some of the Delta variant's signature mutations were underrepresented in our study due to artifacts of the used bioinformatics tools, approach and sequencing method. We therefore discuss some pitfalls and considerations when sequencing SARS-CoV-2 genomes.Conclusion: Our results suggest that genomic surveillance in a small, representative cohort can be used to make predictions about the circulating variants nationally. Moreover, we show that detection of transient mutations in currently circulating variants can give valuable clues to signature mutations of future VOC. Here we suggest six such mutations, that we detected frequently in the Delta variant during 2021. Lastly, we report multiple systematic errors that occurred when following the ARTIC Network SARS-CoV-2 tiled amplicon approach using the V3 primers and Nanopore sequencing, which led to the masking of some of the important signature mutations in the Delta sequences.
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- Törnell, Andreas, 1994, et al.
(author)
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Presence of MDSC associates with impaired antigen-specific T cell reactivity following COVID-19 vaccination in cirrhotic patients
- 2023
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In: Frontiers in Immunology. - 1664-3224. ; 14
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Journal article (peer-reviewed)abstract
- Background and aims: Cirrhosis entails high risk of serious infections and abated efficiency of vaccination, but the underlying mechanisms are only partially understood. This study aimed at characterizing innate and adaptive immune functions, including antigen-specific T cell responses to COVID-19 vaccination, in patients with compensated and decompensated cirrhosis. Methods: Immune phenotype and function in peripheral blood from 42 cirrhotic patients and 44 age-matched healthy controls were analysed after two doses of the mRNA-based COVID-19 vaccines [BNT162b2 (Pfizer BioNTech) or mRNA-1273 (Moderna)]. Results: Cirrhotic patients showed significantly reduced blood counts of antigen-presenting dendritic cells (DC) and high counts of monocytic myeloid-derived suppressor cells (M-MDSC) as compared to healthy controls. In addition, monocytic cells recovered from cirrhotic patients showed impaired expression of the antigen-presenting molecule HLA-DR and the co-stimulatory molecule CD86 upon Toll-like receptor (TLR) stimulation. These features were more prominent in patients with decompensated cirrhosis (Child-Pugh classes B & C). Interestingly, while patients with compensated cirrhosis (Child-Pugh class A) showed an inflammatory profile with myeloid cells producing the proinflammatory cytokines IL-6 and TNF, decompensated patients produced reduced levels of these cytokines. Cirrhotic patients, in particular those with more advanced end-stage liver disease, mounted reduced antigen-specific T cell reactivity to COVID-19 vaccination. Vaccine efficiency inversely correlated with levels of M-MDSC. Conclusion: These results implicate MDSC as mediators of immunosuppression, with ensuing deficiency of vaccine-specific T cell responses, in cirrhosis.
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