The first study of the prevalence and genetic diversity of Theileria equi and Babesia caballi in horses in Russia.

Equine piroplasmosis (EP) is a global worldwide infection, which can lead to the death of animals. Despite the causative agents of EP being well studied, there are no data on the distribution and genetic characteristics of EP agents in any region of Russia. In this study, blood samples from 750 horses from Novosibirsk province, Irkutsk province, and Altai region of Russian Siberia were examined for the presence of EP agents. Theileria equi and Babesia caballi were detected in all examined regions, with mean prevalence rates of 60.4% and 7.2%, respectively. The identified pathogens were genetically characterized by the 18S rRNA gene. The determined T. equi sequences were highly conserved and belonged to genotypes A and E, with genotype E being found in 88.6% of genotyped samples. In contrast to T. equi, B. caballi sequences were genetically diverse. Seven sequence variants of B. caballi were identified, and only two of them matched known sequences from the GenBank database. The determined B. caballi sequences belonged to four distinct branches within genotype A. Mixed infections with several variants of B. caballi or with T. equi and B. caballi were common. The conducted phylogenetic analysis based on all available B. caballi sequences of the 18S rRNA gene (> 900 bp) from GenBank and from this study first demonstrated the presence of five monophyletic clusters within genotype A and three clusters within genotype B. Thus, the genetic study of B. caballi from Siberia has significantly expanded the data on the genetic diversity of this pathogen.

Intestinal Microbiome Changes and Clinical Outcomes of Patients with Ulcerative Colitis after Fecal Microbiota Transplantation.

BACKGROUND AND AIMS: Ulcerative colitis (UC) is a chronic inflammatory disease that affects many people. One of the possible ways to treat UC is fecal microbiota transplantation (FMT). In this study, changes in the intestinal microbiome and clinical outcomes of 20 patients with UC after FMT were estimated. METHODS: FMT enemas were administrated ten times, once a day, and fecal microbiota from three donors was used for each enema. The clinical outcomes were assessed after eight weeks and then via a patient survey. The 16S rRNA profiles of the gut microbiota were compared between three samplings: samples from 20 patients with UC before and after FMT and samples from 18 healthy volunteers. RESULTS: Clinical remission was achieved in 19 (95%) patients at week 8. Adverse events occurred in five patients, including one non-responder. A significant increase in average biodiversity was shown in samples after FMT compared to samples before FMT, as well as a decrease in the proportion of some potentially pathogenic bacteria. CONCLUSION: The efficacy of FMT for UC treatment was confirmed; however, the duration of remission varied substantially, possibly due to different characteristics of the initial microbiota of patients. Targeted analysis of a patient's microbiome before FMT could increase the treatment efficacy.

Tentaclins-A Novel Family of Phage Receptor-Binding Proteins That Can Be Hypermutated by DGR Systems.

Diversity-generating retroelements (DGRs) are prokaryotic systems providing rapid modification and adaptation of target proteins. In phages, the main targets of DGRs are receptor-binding proteins that are usually parts of tail structures and the variability of such host-recognizing structures enables phage adaptation to changes on the bacterial host surface. Sometimes, more than one target gene containing a hypermutated variable repeat (VR) can be found in phage DGRs. The role of mutagenesis of two functionally different genes is unclear. In this study, several phage genomes that contain DGRs with two target genes were found in the gut virome of healthy volunteers. Bioinformatics analysis of these genes indicated that they encode proteins with different topology; however, both proteins contain the C-type lectin (C-lec) domain with a hypermutated beta-hairpin on its surface. One of the target proteins belongs to a new family of proteins with a specific topology: N-terminal C-lec domain followed by one or more immunoglobulin domains. Proteins from the new family were named tentaclins after TENTACLe + proteIN. The genes encoding such proteins were found in the genomes of prophages and phages from the gut metagenomes. We hypothesized that tentaclins are involved in binding either to bacterial receptors or intestinal/immune cells.

Isolation, Characterization and Genomic Analysis of a Novel Jumbo Phage, AerS_266, That Infects Aeromonas salmonicida.

Aeromonas salmonicida is the causative agent of septicemia in fish, and it is associated with significant economic losses in the aquaculture industry. While piscine Aeromonas infections are mainly treated with antibiotics, the emergence of resistance in bacterial populations requires the development of alternative methods of treatment. The use of phages can be one of them. A novel A. salmonicida jumbo phage, AerS_266, was isolated and characterized. This phage infects only mesophilic A. salmonicida strains and demonstrates a slow lytic life cycle. Its genome contains 243,674 bp and 253 putative genes: 84 encode proteins with predicted functions, and 3 correspond to tRNAs. Genes encoding two multisubunit RNA polymerases, chimallin and PhuZ, were identified, and AerS_266 was thus defined as a phiKZ-like phage. While similar phages with genomes >200 kb specific to Aeromonas hydrophila and Aeromonas veronii have been previously described, AerS_266 is the first phiKZ-like phage found to infect A. salmonicida.