ORIGINAL RESEARCH article
Front. Microbiol.
Sec. Infectious Agents and Disease
Taxonomic landscape of the Mycobacterium "Fortuitum-Vaccae" clade: a genome study
Provisionally accepted
- 1West China Hospital, Sichuan University, Chengdu, China
- 2University of Birmingham, Birmingham, United Kingdom
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The Mycobacterium "Fortuitum-Vaccae" clade (FVC) contains many rapid-growing species and is increasingly reported in human infections globally. However, the clade's taxonomic composition and the exact association with human infections remain to be explored. In this study, we conducted a comprehensive genome-based analysis of the FVC, aiming to update its taxonomy and identify new taxa. We compiled a dataset of 298 Mycobacterium species using public databases, ultimately including 222 type strain genomes for phylogenomic analysis. This revealed 106 species within the FVC. Subsequent curation of 11,534 public Mycobacterium genomes identified 557 belonging to the FVC, from which we uncovered 86 new taxa (genomospecies) and resolved one new synonym pair. We reconstructed three core-protein phylogenomic trees and found the FVC comprising eight distinct subclades. Our analysis unveiled a remarkably complicated taxonomic landscape within the clade, encompassing 106 known species, among which 16 species, such as M. syngnathidarum and M. yunnanensis, have not previously been classified within the FVC. We detected a pair of synonyms: M. murale is a heterotypic synonym of M. tokaiense. In conclusion, these findings highlight the remarkable taxonomic diversity within the FVC. The updated taxonomy and the curated database of genomes allow precise species identification in diagnostics, clinical reporting, epidemiological surveillance, and future studies on the ecology and pathogenesis. Accurate identification may uncover the disease spectrum, clinical manifestation, and prognosis of infections by individual FVC species, guiding countermeasures.
Keywords: Mycobacterium, Mycobacterium fortuitum, Mycobacterium vaccae, Non-tuberculosis mycobacteria, Taxonomy
Received: 28 Oct 2025; Accepted: 26 Jan 2026.
Copyright: © 2026 Zong, Wang, Feng, Zhou, Zhao, Xiao, Xie and Mcnally. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Zhiyong Zong
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