| 1. |
- Bai, Xiangning, et al.
(författare)
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Comparative Genomics of Shiga Toxin-Producing Escherichia coli Strains Isolated from Pediatric Patients with and without Hemolytic Uremic Syndrome from 2000 to 2016 in Finland
- 2022
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Ingår i: Microbiology Spectrum. - : American Society for Microbiology. - 2165-0497. ; 10:4
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Tidskriftsartikel (refereegranskat)abstract
- Shiga toxin-producing Escherichia coli (STEC) is a serious public health burden worldwide which causes outbreaks of gastrointestinal diseases and the fatal hemolytic uremic syndrome (HUS) characterized by the triad of mechanical hemolytic anemia, thrombocytopenia, and acute renal failure. Understanding the mechanism underlying the disease severity and patient outcome is of high importance. Shiga toxin-producing Escherichia coli (STEC) infection can cause mild to severe illness, such as nonbloody or bloody diarrhea, and the fatal hemolytic uremic syndrome (HUS). The molecular mechanism underlying the variable pathogenicity of STEC infection is not fully defined so far. Here, we performed a comparative genomics study on a large collection of clinical STEC strains collected from STEC-infected pediatric patients with and without HUS in Finland over a 16-year period, aiming to identify the bacterial genetic factors that can predict the risk to cause HUS and poor renal outcome. Of 240 STEC strains included in this study, 52 (21.7%) were from pediatric patients with HUS. Serotype O157:H7 was the main cause of HUS, and Shiga toxin gene subtype stx2a was significantly associated with HUS. Comparative genomics and pangenome-wide association studies identified a number of virulence and accessory genes overrepresented in HUS-associated STEC compared to non-HUS STEC strains, including genes encoding cytolethal distending toxins, type III secretion system effectors, adherence factors, etc. No virulence or accessory gene was significantly associated with risk factors for poor renal outcome among HUS patients assessed in this study, including need for and duration of dialysis, presence and duration of anuria, and leukocyte counts. Whole-genome phylogeny and multiple-correspondence analysis of pangenomes could not separate HUS STEC from non-HUS STEC strains, suggesting that STEC strains with diverse genetic backgrounds may independently acquire genetic elements that determine their varied pathogenicity. Our findings indicate that nonbacterial factors, i.e., characteristics of the host immunity, might affect STEC virulence and clinical outcomes. IMPORTANCE Shiga toxin-producing Escherichia coli (STEC) is a serious public health burden worldwide which causes outbreaks of gastrointestinal diseases and the fatal hemolytic uremic syndrome (HUS) characterized by the triad of mechanical hemolytic anemia, thrombocytopenia, and acute renal failure. Understanding the mechanism underlying the disease severity and patient outcome is of high importance. Using comparative genomics on a large collection of clinical STEC strains from STEC-infected patients with and without HUS, our study provides a reference of STEC genetic factors/variants that can be used as predictors of the development of HUS, which will aid risk assessment at the early stage of STEC infection. Additionally, our findings suggest that nonbacterial factors may play a primary role in the renal outcome in STEC-infected patients with HUS; further studies are needed to validate this.
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| 2. |
- Bai, Xiangning, et al.
(författare)
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Whole-Genome Metagenomic Analysis of the Gut Microbiome in HIV-1-Infected Individuals on Antiretroviral Therapy
- 2021
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Ingår i: Frontiers in Microbiology. - : Frontiers Media S.A.. - 1664-302X. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Gut microbiome plays a significant role in HIV-1 immunopathogenesis and HIV-1-associated complications. Previous studies have mostly been based on 16S rRNA gene sequencing, which is limited in taxonomic resolution at the genus level and inferred functionality. Herein, we performed a deep shotgun metagenomics study with the aim to obtain a more precise landscape of gut microbiome dysbiosis in HIV-1 infection. A reduced tendency of alpha diversity and significantly higher beta diversity were found in HIV-1-infected individuals on antiretroviral therapy (ART) compared to HIV-1-negative controls. Several species, such as Streptococcus anginosus, Actinomyces odontolyticus, and Rothia mucilaginosa, were significantly enriched in the HIV-1-ART group. Correlations were observed between the degree of immunodeficiency and gut microbiome in terms of microbiota composition and metabolic pathways. Furthermore, microbial shift in HIV-1-infected individuals was found to be associated with changes in microbial virulome and resistome. From the perspective of methodological evaluations, our study showed that different DNA extraction protocols significantly affect the genomic DNA quantity and quality. Moreover, whole metagenome sequencing depth affects critically the recovery of microbial genes, including virulome and resistome, while less than 5 million reads per sample is sufficient for taxonomy profiling in human fecal metagenomic samples. These findings advance our understanding of human gut microbiome and their potential associations with HIV-1 infection. The methodological assessment assists in future study design to accurately assess human gut microbiome.
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| 3. |
- Cena-Diez, Rafael, et al.
(författare)
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Naturally occurring dipeptide from elite controllers with dual anti-HIV-1 mechanism
- 2023
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Ingår i: International Journal of Antimicrobial Agents. - : Elsevier BV. - 0924-8579 .- 1872-7913. ; 61:5, s. 106792-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Enhanced levels of a dipeptide, WC-am, have been reported among elite controllers - patients who spontaneously control their HIV-1 infection. This study aimed to evaluate anti-HIV-1 activity and mechanism of action of WC-am.Methods: Drug sensitivity assays in TZM.bl cells, PBMCs and ACH-2 cells using WT and mutated HIV-1 strains were performed to evaluate the antiviral mechanism of WC-am. Mass spectrometry-based proteomics and Real-time PCR analysis of reverse transcription steps were performed to unravel the second anti-HIV-1 mechanism of WC-am.Results: The data suggest that WC-am binds to the CD4 binding pocket of HIV-1 gp120 and blocks its binding to the host cell receptors. Additionally, the time course assay showed that WC-am also inhibited HIV-1 at 4-6 hours post-infection, suggesting a second antiviral mechanism. Drug sensitivity assays under acidic wash conditions confirmed the ability of WC-am to internalise into the host cell in an HIV independent manner. Proteomic studies showed a clustering of all samples treated with WC-am independent of the number of doses or presence or absence of HIV-1. Differentially expressed proteins due to the WC-am treatment indicated an effect on HIV-1 reverse transcription, which was confirmed by reverse transcriptase polymerase chain reaction (RT-PCR).Conclusion: Naturally occurring in HIV-1 elite controllers, WC-am stands out as a new kind of antiviral compound with two independent inhibitory mechanisms of action on HIV-1 replication. WC-am halts HIV-1 entry to the host cell by binding to HIV-1 gp120, thereby blocking the binding of HIV-1 to the host cell. WC-am also exerts a post-entry but pre-integration antiviral effect related to RT-activity.
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| 4. |
- Narayanan, Aswathy, et al.
(författare)
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Exploring the interplay between antiretroviral therapy and the gut-oral microbiome axis in people living with HIV
- 2024
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Ingår i: Scientific Reports. - 2045-2322. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- The gut and oral microbiome is altered in people living with HIV (PLWH). While antiretroviral treatment (ART) is pivotal in restoring immune function in PLWH, several studies have identified an association between specific antiretrovirals, particularly integrase inhibitors (INSTI), and weight gain. In our study, we explored the differences in the oral and gut microbiota of PLWH under different ART regimens, and its correlation to Body Mass Index (BMI). Fecal and salivary samples were collected from PLWH (n = 69) and healthy controls (HC, n = 80). We performed taxonomy analysis to determine the microbial composition and relationship between microbial abundance and ART regimens, BMI, CD4+T-cell count, CD4/CD8 ratio, and ART duration. PLWH showed significantly lower richness compared to HC in both the oral and gut environment. The gut microbiome composition of INSTI-treated individuals was enriched with Faecalibacterium and Bifidobacterium, whereas non-nucleotide reverse transcriptase inhibitor (NNRTI)-treated individuals were enriched with Gordonibacter, Megasphaera, and Staphylococcus. In the oral microenvironment, Veillonella was significantly more abundant in INSTI-treated individuals and Fusobacterium and Alloprevotella in the NNRTI-treated individuals. Furthermore, Bifidobacterium and Dorea were enriched in gut milieu of PLWH with high BMI. Collectively, our findings identify distinct microbial profiles, which are associated with different ART regimens and BMI in PLWH on successful ART, thereby highlighting significant effects of specific antiretrovirals on the microbiome.Similar content being viewed by others
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| 5. |
- Ray, Shilpa, et al.
(författare)
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Altered Gut Microbiome under Antiretroviral Therapy : Impact of Efavirenz and Zidovudine
- 2021
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Ingår i: ACS - Infectious Diseases. - : American Chemical Society (ACS). - 2373-8227. ; 7:5, s. 1104-1115
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Tidskriftsartikel (refereegranskat)abstract
- Millions of individuals currently living with HIV globally are receiving antiretroviral therapy (ART) that suppresses viral replication and improves host immune responses. The involvement of gut microbiome during HIV infection has been studied, exposing correlation with immune status and inflammation. However, the direct effect of ART on gut commensals of HIV-infected individuals has been mostly overlooked in microbiome studies. We used 16S rRNA sequencing (Illumina MiSeq) for determining the microbiota composition of stool samples from 16 viremic patients before and one year after ART. We also tested the direct effect of 15 antiretrovirals against four gut microbes, namely, Escherichia coli, Enterococcus faecalis, Bacteroides, and Prevotella to assess their in vitro antibacterial effect. 16S rRNA analysis of fecal samples showed that effective ART for one year does not restore the microbiome diversity in HIV-infected patients. A significant reduction in α-diversity was observed in patients under non-nucleoside reverse transcriptase inhibitors; (NNRTI; 2 NRTI+NNRTI; NRTIs are nucleoside reverse transcriptase inhibitors) as compared to ritonavir-boosted protease inhibitors (PI/r; 2 NRTI+PI/r). Prevotella (P = 0.00001) showed a significantly decreased abundance in patients after ART (n = 16). We also found the direct effect of antivirals on gut microbes, where zidovudine (ZDV) and efavirenz (EFV) showed in vitro antimicrobial activity against Bacteroides fragilis and Prevotella. EFV also inhibited the growth of E. faecalis. Therefore, we observed that ART does not reverse the HIV-induced gut microbiome dysbiosis and might aggravate those microbiota alterations due to the antibacterial effect of certain antiretrovirals (like EFV, ZDV). Our results imply that restructuring the microbiota could be a potential therapeutic target in HIV-1 patients under ART.
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| 6. |
- Ray, Shilpa, et al.
(författare)
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Impact of the gut microbiome on immunological responses to COVID-19 vaccination in healthy controls and people living with HIV
- 2023
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Ingår i: npj Biofilms and Microbiomes. - 2055-5008. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Although mRNA SARS-CoV-2 vaccines are generally safe and effective, in certain immunocompromised individuals they can elicit poor immunogenic responses. Among these individuals, people living with HIV (PLWH) have poor immunogenicity to several oral and parenteral vaccines. As the gut microbiome is known to affect vaccine immunogenicity, we investigated whether baseline gut microbiota predicts immune responses to the BNT162b2 mRNA SARS-CoV-2 vaccine in healthy controls and PLWH after two doses of BNT162b2. Individuals with high spike IgG titers and high spike-specific CD4 + T-cell responses against SARS-CoV-2 showed low α-diversity in the gut. Here, we investigated and presented initial evidence that the gut microbial composition influences the response to BNT162b2 in PLWH. From our predictive models, Bifidobacterium and Faecalibacterium appeared to be microbial markers of individuals with higher spike IgG titers, while Cloacibacillus was associated with low spike IgG titers. We therefore propose that microbiome modulation could optimize immunogenicity of SARS-CoV-2 mRNA vaccines.
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