Biomedical subjects

Oleg N Reva

Publications and source records attributed to Oleg N Reva.

2 recordsLinked to original sources

PubMed2026

Patterns of Drug Resistance, Drug Resistance Conferring Mutations and Genomic DNA Methylation Revealed in Mycobacterium tuberculosis From South Africa.

Tuberculosis remains a major public health threat globally, with drug-resistant strains undermining treatment efficacy. We analyzed 126 Mycobacterium tuberculosis (M. tuberculosis) isolates with diverse drug resistance spectra and selected 35 for whole genome sequencing (WGS) using Illumina NextSeq, SMRT PacBio Onso and SMRT PacBio Revio sequencing platforms. The study aimed to characterize drug resistance profiles, compare short- and long-read sequencing performance, identify lineages among South African isolates, detect known drug resistance mutations and their lineage-specific patterns, and utilize long-read SMRT platforms for epigenetic profiling. Multiple drug resistance mutations were identified, some lineage-specific, and notably, East-African-Indian (EAI) Lineage 1 isolates often considered less pathogenic, showed significant potential for multidrug-resistance development, including higher fluoroquinolone resistance as compared to other lineages. Three DNA motifs with methylated adenines, namely CACGCaG, CtCCaG and GaTNNNNRtAC, were detected, with methylation patterns varying by lineage and strain due to mutations in the corresponding methyltransferases (MTases). A particularly notable finding was the stable maintenance of a genetic heterogeneity in the mamB MTase, performing methylation at CACGCaG motifs. These results highlight the combined role of genetic and epigenetic variation in M. tuberculosis adaptive evolution and underscore the value of integrating long-read sequencing into TB surveillance and research.

Mycobacterium tuberculosis↗

PubMed2025

Whole genome sequencing of Yersinia pestis isolates from Central Asian natural plague foci revealed the role of adaptation to different hosts and environmental conditions in shaping specific genotypes.

The genetic diversity and biovar classification of Yersinia isolates from Central Asia were investigated using whole-genome sequencing. In total, 98 isolates from natural plague foci were sequenced using the MiSeq platform. Computational pipelines were developed for accurate assembly of Y. pestis replicons, including small cryptic plasmids, and for identifying genetic polymorphisms. A panel of 99 diagnostic polymorphisms was established, enabling the distinction of dominant Medievalis isolates derived from desert and upland regions. Evidence of convergent evolution was observed in polymorphic allele distributions across genetically distinct Y. pestis biovars, Y. pseudotuberculosis, and other Y. pestis strains, likely driven by adaptation to similar environmental conditions. Genetic polymorphisms in the napA, araC, ssuA, and rhaS genes, along with transposon and CRISPR-Cas insertion patterns, were confirmed as suitable tools for identifying Y. pestis biovars, although their homoplasy suggests limited utility for phylogenetic inference. Notably, a novel cryptic plasmid, pCKF, previously associated with the strain of the population 2.MED0 from the Central-Caucasus high-altitude autonomous plague focus, was detected in a genetically distinct isolate of 2.MED1 population from the Ural-Embi region, indicating potential plasmid transfer across the 2.MED lineage. These findings emphasize the need for ongoing genomic surveillance to monitor the spread of virulence-associated genetic elements and to improve our understanding of Y. pestis evolution and ecology.

Yersinia pestis↗