Intestinal microbiota composition of children with infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and multisystem inflammatory syndrome (MIS-C).

Microbiota composition may play a role in the development, prognosis, or post-infection of COVID-19. There are studies evaluating the microbiota composition at the time of diagnosis and during the course of COVID-19, especially in adults, while studies in children are limited and no study available in children with multisystem inflammatory syndrome in children (MIS-C). This study was planned to compare intestinal microbiota composition in children diagnosed with MIS-C and acute COVID-19 infection with healthy children. In this prospective multicenter study, 25 children diagnosed with MIS-C, 20 with COVID-19 infection, and 19 healthy children were included. Intestinal microbiota composition was evaluated by 16 s rRNA gene sequencing. We observed changes of diversity, richness, and composition of intestinal microbiota in MIS-C cases compared to COVID-19 cases and in the healthy controls. The Shannon index was higher in the MIS-C group than the healthy controls (p < 0.01). At phylum level, in the MIS-C group, a significantly higher relative abundance of Bacteroidetes and lower abundance of Firmicutes was found compared to the control group. Intestinal microbiota composition changed in MIS-C cases compared to COVID-19 and healthy controls, and Faecalibacterium prausnitzii decreased; Bacteroides uniformis, Bacteroides plebeius, Clostridium ramosum, Eubacterium dolichum, Eggerthella lenta, Bacillus thermoamylovorans, Prevotella tannerae, and Bacteroides coprophilus were dominant in children with MIS-C. At species level, we observed decreased Faecalibacterium prausnitzii, and increased Eubacterium dolichum, Eggerthella lenta, and Bacillus thermoamylovorans in children with MIS-C and increased Bifidobacterium adolescentis and Dorea formicigenerasus in the COVID-19 group. Our study is the first to evaluate the microbiota composition in MIS-C cases. There is a substantial change in the composition of the gut microbiota: (1) reduction of F. prausnitzii in children with MIS-C and COVID-19; (2) an increase of Eggerthella lenta which is related with autoimmunity; and (3) the predominance of E. dolichum is associated with metabolic dysfunctions and obesity in children with MIS-C. CONCLUSIONS:  Alterations of the intestinal microbiota might be part of pathogenesis of predisposing factor for MIS-C. It would be beneficial to conduct more extensive studies on the cause-effect relationship of these changes in microbiota composition and their effects on long-term prognosis. WHAT IS KNOWN: • Microbiota composition may play a role in the development, prognosis, or post-infection of COVID-19.  • However, the number of studies on children is limited, and no study on multisystem inflammatory syndrome in children is currently available (MIS-C). WHAT IS NEW: • In individuals with MIS-C, the composition of the gut microbiota changed dramatically. • Decreased Faecalibacterium prausnitzii have been observed, increased Eggerthella lenta, which was previously linked to autoimmunity, and predominance of Eubacterium dolichum which was linked to metabolic dysfunction and obesity.

A cross-sectional overview of SARS-CoV-2 genome variations in Turkey

We assessed SARS-CoV-2 genome diversity and probable impact on epidemiology, immune response and clinical disease in Turkey.Complete genomes and partial Spike (S) sequences were accessed from the Global Initiative on Sharing Avian Influenza Data (GISAID) database. The genomes were analysed for variations and recombinations using appropriate softwares.Four hundred ten complete genomes and 206 S region sequences were included. Overall, 1,200 distinct nucleotide variations were noted. Mean variation count was 14.2 per genome and increased significantly during the course of the pandemic. The most frequent variations were identified as A23403G (D614G;92.9,%), C14408T (P323L, 92.2%), C3037T (89.8%), C241T (83.4%) and GGG28881AAC (RG203KR, 62.6%). The A23403G mutation was the most frequent variation in the S region sequences (99%). Most genomes (98.3%) belonged in the SARS-CoV-2 haplogroup A. No evidence for recombination was identified in genomes representing sub-haplogroup branches. The variants B.1.1.7, B.1.351 and P.1 were detected, with a statistically-significant time-associated increase in B.1.1.7 prevalence.We described prominent SARS-CoV-2 variations as well as comparisons with global virus diversity. Continuing a molecular surveillance in agreement with local disease epidemiology appears to be crucial, as vaccination and mitigation efforts are ongoing. (English) [ABSTRACT FROM AUTHOR] Türkiye kaynaklı SARS-CoV-2 genomik dizi çeşitliliğinin ve epidemiyoloji, bağışık yanıt ve hastalık seyri üzerine muhtemel etkili varyasyonların incelenmesi.“Global Initiative on Sharing Avian Influenza Data” (GISAID) veri tabanında yer alan tüm genom ve “Spike” (S) bölgesine ait verilere ulaşılarak uygun yazılımlar yardımıyla varyasyon ve muhtemel rekombinasyonlar araştırıldı.Toplam 410 tam genom ve 206 S bölgesi dizisi incelendi, 1200 farklı nükleotid düzeyinde varyasyon saptandı. Genom başına toplam varyasyon ortalaması 14.2 olarak hesaplandı ve salgının ilerleyişi süresince istatistiksel olarak anlamlı artış izlendi. En sık saptanan varyasyonlar A23403G (D614G;92.9,%), C14408T (P323L, 92.2%), C3037T (89.8%), C241T (83.4%) ve GGG28881AAC (RG203KR, 62.6%) olarak sıralandı. S bölgesi dizilerinde de A23403G, en yaygın varyasyon (%99) şeklinde izlendi. Íncelenen genomların sıklıkla (%98.3) SARS-CoV-2 A haplogrubuna ait olduğu görüldü. Alt haplogrupları temsil eden genomlarda yapılan incelemelerde rekombinasyon bulgusu saptanmadı. Çalışma grubunda B.1.1.7, B.1.351 ve P.1 varyantları tespit edildi. B.1.1.7 prevalansında izlenen zamanla ilişkili artış, istatistiksel olarak anlamlı bulundu.Çalışmada ülkemiz kaynaklı SARS-CoV-2 genomlarında belli başlı varyasyonlar belirlenmiş ve küresel virüs çeşitliliği ışığında değerlendirilmiştir. Kontrol ve aşılama çalışmaları ile eşzamanlı olarak önemli varyantların tanımlanabilmesi için, bölgesel epidemiyoloji ile uyumlu moleküler sürveyans çalışmaları sürdürülmelidir. (Turkish) [ABSTRACT FROM AUTHOR] Copyright of Turkish Journal of Biochemistry / Turk Biyokimya Dergisi is the property of De Gruyter and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Using bioinformatic protein sequence similarity to investigate if SARS CoV-2 infection could cause an ocular autoimmune inflammatory reactions?

Although severe acute respiratory syndrome coronavirus 2 (SARS CoV-2) infection have emerged globally, findings related to ocular involvement and reported cases are quite limited. Immune reactions against viral infections are closely related to viral and host proteins sequence similarity. Molecular Mimicry has been described for many different viruses; sequence similarities of viral and human tissue proteins may trigger autoimmune reactions after viral infections due to similarities between viral and human structures. With this study, we aimed to investigate the protein sequence similarity of SARS CoV-2 with retinal proteins and retinal pigment epithelium (RPE) surface proteins. Retinal proteins involved in autoimmune retinopathy and retinal pigment epithelium surface transport proteins were analyzed in order to infer their structural similarity to surface glycoprotein (S), nucleocapsid phosphoprotein (N), membrane glycoprotein (M), envelope protein (E), ORF1ab polyprotein (orf1ab) proteins of SARS CoV-2. Protein similarity comparisons, 3D protein structure prediction, T cell epitopes-MHC binding prediction, B cell epitopes-MHC binding prediction and the evaluation of the antigenicity of peptides assessments were performed. The protein sequence analysis was made using the Pairwise Sequence Alignment and the LALIGN program. 3D protein structure estimates were made using Swiss Model with default settings and analyzed with TM-align web server. T-cell epitope identification was performed using the Immune Epitope Database and Analysis (IEDB) resource Tepitool. B cell epitopes based on sequence characteristics of the antigen was performed using amino acid scales and HMMs with the BepiPred 2.0 web server. The predicted peptides/epitopes in terms of antigenicity were examined using the default settings with the VaxiJen v2.0 server. Analyses showed that, there is a meaningful similarities between 6 retinal pigment epithelium surface transport proteins (MRP-4, MRP-5, RFC1, SNAT7, TAUT and MATE) and the SARS CoV-2 E protein. Immunoreactive epitopic sites of these proteins which are similar to protein E epitope can create an immune stimulation on T cytotoxic and T helper cells and 6 of these 9 epitopic sites are also vaxiJen. These result imply that autoimmune cross-reaction is likely between the studied RPE proteins and SARS CoV-2 E protein. The structure of SARS CoV-2, its proteins and immunologic reactions against these proteins remain largely unknown. Understanding the structure of SARS CoV-2 proteins and demonstration of similarity with human proteins are crucial to predict an autoimmune response associated with immunity against host proteins and its clinical manifestations as well as possible adverse effects of vaccination.