Mobile Colistin Resistance Genetic Determinants of Non-Typhoid Salmonella enterica Isolates from Russia.

Polymyxin resistance, determined by mcr genes located on plasmid DNA, currently poses a high epidemiological threat. Non-typhoid Salmonella (NTS) are one of the key pathogens causing diarrheal diseases. Here, we report the isolation and whole genome sequencing of multidrug colistin-resistant/susceptible isolates of non-typhoid Salmonella enterica serovars carrying mcr genes. Non-typhoid strains of Salmonella enterica subsp. enterica were isolated during microbiological monitoring of the environment, food, and diarrheal disease patients between 2018 and 2020 in Russia (n = 586). mcr-1 genes were detected using a previously developed qPCR assay, and whole genome sequencing of mcr positive isolates was performed by both short-read (Illumina) and long-read (Oxford Nanopore) approaches. Three colistin-resistant isolates, including two isolates of S. Enteritidis and one isolate of S. Bovismorbificans, carried the mcr-1.1 gene located on IncX4 and IncI2 conjugative plasmids, respectively. The phenotypically colistin-susceptible isolate of S. Typhimurium carried a mcr-9 gene on plasmid IncHI2. In conclusion, we present the first three cases of mcr gene-carrying NTS isolates detected in Russia with both outbreak and sporadic epidemiological backgrounds.

Whole genome sequencing of Borrelia miyamotoi isolate Izh-4: reference for a complex bacterial genome.

BACKGROUND: The genus Borrelia comprises spirochaetal bacteria maintained in natural transmission cycles by tick vectors and vertebrate reservoir hosts. The main groups are represented by a species complex including the causative agents of Lyme borreliosis and relapsing fever group Borrelia. Borrelia miyamotoi belongs to the relapsing fever group of spirochetes and forms distinct populations in North America, Asia, and Europe. As all Borrelia species B. miyamotoi possess an unusual and complex genome consisting of a linear chromosome and a number of linear and circular plasmids. The species is considered an emerging human pathogen and an increasing number of human cases are being described in the Northern hemisphere. The aim of this study was to produce a high quality reference genome that will facilitate future studies into genetic differences between different populations and the genome plasticity of B. miyamotoi. RESULTS: We used multiple available sequencing methods, including Pacific Bioscience single-molecule real-time technology (SMRT) and Oxford Nanopore technology (ONT) supplemented with highly accurate Illumina sequences, to explore the suitability for whole genome assembly of the Russian B. miyamotoi isolate, Izh-4. Plasmids were typed according to their potential plasmid partitioning genes (PF32, 49, 50, 57/62). Comparing and combining results of both long-read (SMRT and ONT) and short-read methods (Illumina), we determined that the genome of the isolate Izh-4 consisted of one linear chromosome, 12 linear and two circular plasmids. Whilst the majority of plasmids had corresponding contigs in the Asian B. miyamotoi isolate FR64b, there were only four that matched plasmids of the North American isolate CT13-2396, indicating differences between B. miyamotoi populations. Several plasmids, e.g. lp41, lp29, lp23, and lp24, were found to carry variable major proteins. Amongst those were variable large proteins (Vlp) subtype Vlp-α, Vlp-γ, Vlp-δ and also Vlp-ß. Phylogenetic analysis of common plasmids types showed the uniqueness in Russian/Asian isolates of B. miyamotoi compared to other isolates. CONCLUSIONS: We here describe the genome of a Russian B. miyamotoi clinical isolate, providing a solid basis for future comparative genomics of B. miyamotoi isolates. This will be a great impetus for further basic, molecular and epidemiological research on this emerging tick-borne pathogen.

Draft Whole-Genome Sequences of Two Western European Borrelia miyamotoi Isolates.

We report the draft whole-genome sequences of two Borrelia miyamotoi strains isolated in The Netherlands. Using next-generation sequencing, we determined the complete sequence of the chromosomes and several plasmids. The two strains show a genotype typical of European strains, distinct from the genomes of strains from Asia or the United States.

Draft Genome Sequence of Microbacterium sp. Gd 4-13, Isolated from Gydanskiy Peninsula Permafrost Sediments of Marine Origin.

Here, we report the draft genome sequence of Microbacterium sp. strain Gd 4-13, isolated from late Pleistocene permafrost of marine origin located on the Gydanskiy Peninsula. Genome sequence analysis was performed to understand strain survivability mechanisms under permafrost conditions and to expand biotechnology applications.

Whole-Genome Sequencing of Six Borrelia miyamotoi Clinical Strains Isolated in Russia.

Here, we report the whole-genome sequence of six clinical Borrelia miyamotoi isolates from the Russian Federation. Using two independent next-generation sequencing platforms, we determined the complete sequence of the chromosome and several plasmids. All strains have an Asian genotype with 99.8% chromosome nucleotide similarity with B. miyamotoi strain FR64b.

Comparative genomic analysis of two isolates of Vibrio cholerae O1 Ogawa El Tor isolated during outbreak in Mariupol in 2011.

Cholera is a water-borne, severe enteric infection essentially caused by toxigenic strains of Vibrio cholera O1 and O139 serogroups. An outbreak of cholera was registered during May-July 2011 in Mariupol, Ukraine, with 33 cholera cases and 25 carriers of cholera. Following this outbreak, the toxigenic strain of V. cholerae 2011EL-301 was isolated from seawater in the recreation area of Taganrog city on the territory of Russia. The aim of our study was to understand genomic features of Mariupol isolates as well as to evaluate hypothesis about possible interconnection between the outbreak of cholera in Mariupol and the single case of isolation of V. cholerae from the Sea of Azov in Russia. Mariupol isolates were phenotypically characterized and subsequently subjected to whole genome sequencing procedure. Phylogenetic analysis based on high-quality SNPs of V. cholera O1 El Tor isolates of the 7th pandemic clade from different regions showed that clinical and environmental isolates from Mariupol outbreak were attributable to a unique phylogenetic clade within wave 3 of V. cholera O1 El Tor isolates and characterized by six clade-specific SNPs. Whereas Taganrog isolate belonged to distantly related clade which allows us to reject the hypothesis of transmission the outbreak strain of V. cholerae O1 from Ukraine to Russia in 2011. Mariupol isolates shared a common ancestor with Haiti\Nepal-4\India clade indicating that outbreak progenitor strain most likely originated in the South Asia region and later was introduced to Ukraine. Moreover, genomic data both based on hqSNPs and similarity of virulence-associated mobile genomic elements of Mariupol isolates suggests that environmental and clinical isolates are a part of joint outbreak which confirms the role of contaminated domestic sewage, as an element of the complex chain of infection spread during cholera outbreak. In general, the genome-wide comparative analysis of both genes and genomic regions of epidemiological importance indicates accessory of this isolates to 'new' clone of toxigenic multiple drug resistance atypical variant of V. cholerae O1 El Tor.

Draft Genome Sequencing of Vibrio cholerae O1 El Tor Isolates Collected in the Russian Federation from Imported Cholera Cases.

We report the draft genome sequencing of five Vibrio cholerae O1 El Tor clinical isolates collected in the Russian Federation from imported cholera cases in 2006, 2010, and 2012. In the initial phylogenetic analysis, one isolate clustered with the Haiti/Nepal-4 group.

Draft Genome Sequences of Vibrio cholerae O1 ElTor Strains 2011EL-301 and P-18785, Isolated in Russia.

We report the draft whole-genome sequences of two Vibrio cholerae O1 strains, the environmental toxigenic strain 2011EL-301 and the clinical nontoxigenic strain P-18785, both isolated in Russia. Some basic data comparing the two against the GenBank repository are provided.

Base-calling algorithm with vocabulary (BCV) method for analyzing population sequencing chromatograms.

Sanger sequencing is a common method of reading DNA sequences. It is less expensive than high-throughput methods, and it is appropriate for numerous applications including molecular diagnostics. However, sequencing mixtures of similar DNA of pathogens with this method is challenging. This is important because most clinical samples contain such mixtures, rather than pure single strains. The traditional solution is to sequence selected clones of PCR products, a complicated, time-consuming, and expensive procedure. Here, we propose the base-calling with vocabulary (BCV) method that computationally deciphers Sanger chromatograms obtained from mixed DNA samples. The inputs to the BCV algorithm are a chromatogram and a dictionary of sequences that are similar to those we expect to obtain. We apply the base-calling function on a test dataset of chromatograms without ambiguous positions, as well as one with 3-14% sequence degeneracy. Furthermore, we use BCV to assemble a consensus sequence for an HIV genome fragment in a sample containing a mixture of viral DNA variants and to determine the positions of the indels. Finally, we detect drug-resistant Mycobacterium tuberculosis strains carrying frameshift mutations mixed with wild-type bacteria in the pncA gene, and roughly characterize bacterial communities in clinical samples by direct 16S rRNA sequencing.