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We investigated the rise of nontuberculous mycobacteria (NTM) infections in Bulgaria, focusing on species identification and distribution from 2018 to 2022. Utilizing advanced diagnostic tools, including the Hain Mycobacterium CM/AS method, Myco-biochip assay, and whole-genome sequencing, the study identifies and characterizes a diverse range of Mycobacterium species from clinical samples. While M. avium, M. gordonae, M. fortuitum, and M. chelonae were dominating, a number of rare species were also found. They include such species as M. marseillense and M. celatum. Moreover, the noticeable prevalence of M. terrae complex species missed by conventional testing was observed. We identified a rare species, highly homologous to previously described strains from Japan; based on genome–genome distance data, we propose its reannotation as a new species. Further, a novel species was identified, which is significantly distinct from its closest neighbor, M. iranicum, with ANI = 87.18%. Based on the SeqCode procedure, we propose to name this new species Mycobacterium bulgaricum sp. nov. Dynamic changes in NTM species prevalence in Bulgaria observed from 2011 to 2022 highlight the emergence of new species and variations tied to environmental and demographic factors. This underscores the importance of accurate species identification and genotyping for understanding NTM epidemiology, informing public health strategies, and enhancing diagnostic accuracy and treatment protocols. [ABSTRACT FROM AUTHOR]

Buryatia is a multidrug-resistant tuberculosis (MDR-TB) high-burden region in the Russian Far East with ethnically diverse population (30 % Mongoloid Buryats and 65 % Russians). Two hundred M. tuberculosis strains from newly-diagnosed patients were subjected to phenotypic testing and genotyping. The Beijing genotype was more prevalent among Russians than Buryats (68 % vs 53 %; P = 0.055). European non-Beijing genotypes (LAM, Ural, Haarlem) were double more prevalent in Buryats vs Russians (39.2 % vs 20.5 %; P = 0.01). Higher prevalence of Beijing among former prison inmates (79 % vs 61 % in other patients, P = 0.1) suggests its increased transmissibility. The Russian epidemic cluster B0/W148 was in 9.5 %, double smaller than elsewhere in Siberia. The hypervirulent Beijing 14717-15-cluster was endemic in Buryatia but paradoxically enough, it was more frequently isolated from Russians than Buryats (9.1 % vs 3.9 %; P = 0.2). Beijing subtypes B0/W148, CAO, and 14717-15 were associated with poly/multi-drug resistance (P = 0.01-0.0001). HIV coinfection was more frequent in Russians than in Buryats: 35/141 (24.8 %) vs 5/51 (9.8 %), P = 0.03. To conclude, M. tuberculosis population structure in Buryatia retained its singularities compared to other parts of Russia and remains strikingly different from the neighboring Mongolia. A circulation of strongly MDR-associated Beijing subtypes and drug-resistant non-Beijing strains highlights a risk of their broader dissemination., Competing Interests: Declaration of competing interest We declare that no competing interests exist., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Species belonging to the Mycobacterium kansasii complex (MKC) are frequently isolated from humans and the environment and can cause serious diseases. The most common MKC infections are caused by the species M. kansasii ( sensu stricto ), leading to tuberculosis-like disease. However, a broad spectrum of virulence, antimicrobial resistance and pathogenicity of these non-tuberculous mycobacteria (NTM) are observed across the MKC. Many genomic aspects of the MKC that relate to these broad phenotypes are not well elucidated. Here, we performed genomic analyses from a collection of 665 MKC strains, isolated from environmental, animal and human sources. We inferred the MKC pangenome, mobilome, resistome, virulome and defence systems and show that the MKC species harbours unique and shared genomic signatures. High frequency of presence of prophages and different types of defence systems were observed. We found that the M. kansasii species splits into four lineages, of which three are lowly represented and mainly in Brazil, while one lineage is dominant and globally spread. Moreover, we show that four sub-lineages of this most distributed M. kansasii lineage emerged during the twentieth century. Further analysis of the M. kansasii genomes revealed almost 300 regions of difference contributing to genomic diversity, as well as fixed mutations that may explain the M. kansasii 's increased virulence and drug resistance.