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Background <p>This study presents the phylogenetic and antimicrobial susceptibility characterization of <i>Mycobacterium monacense</i>, a rare nontuberculous mycobacterium (NTM), cultured from clinical extrapulmonary samples.</p> Methods <p>Eight <i>Mycobacterium monacense</i> isolates were identified between 2019 and 2023 in the Western Cape province of South Africa. Whole-genome sequencing (WGS) was applied to assess phylogenetic relatedness, identify virulence factors, and characterize the resistome of the isolates. Antimicrobial susceptibility testing (AST) was performed using the GenoType NTM-DR line probe assay (LPA), Sensititre minimum inhibitory concentrations (MIC) plates, and the proportional method based on critical concentrations. Spatial distribution of cases was mapped using ArcGIS software.</p> Results <p>Spatiotemporal distribution patterns indicated the presence of circulating clones confined within specific geographical areas. Plasmids coding for ferredoxin and cytochrome P450 genes were identified in one cluster, which notably lacked the chromosomal <i>mbtH </i>gene involved in siderophore biosynthesis for iron acquisition. In contrast, isolates grouped in a second cluster harbored the <i>mbtH</i> chromosomal gene but lacked these plasmid-associated elements. LPA and broth microdilution showed that all <i>Mycobacterium monacense</i> isolates were susceptible to aminoglycosides, fluoroquinolones, and macrolides, but generally exhibited elevated MICs against β-lactam antibiotics. Phenotypic AST indicated that drugs commonly used to treat <i>Mycobacterium tuberculosis</i> complex (MTBC), namely bedaquiline, linezolid, and rifampicin, are effective against <i>Mycobacterium monacense</i>.</p> Conclusion <p><i>Mycobacterium monacense</i> in extrapulmonary cultures accentuates the need for improved diagnostics and enhanced clinical awareness of infections with rare NTM. WGS highlights the potential significance provided by plasmid-encoded genes. Current treatment regimens for MTBC exhibit therapeutic efficacy against <i>Mycobacterium monacense</i> isolates.</p>

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Clonal spread of Mycobacterium monacense strains among patients with extrapulmonary mycobacteriosis

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2025年10月28日

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  • Christoffel Opperman,
  • Aysha Ahmed,
  • Marianna De Kock,
  • Claudia Spies,
  • Michael Biggel,
  • Tristen Lourens,
  • Sarishna Singh,
  • Yonas Ghebrekristos,
  • Robin Warren,
  • Wynand Goosen,
  • Giovanni Ghielmetti

摘要

Background

This study presents the phylogenetic and antimicrobial susceptibility characterization of Mycobacterium monacense, a rare nontuberculous mycobacterium (NTM), cultured from clinical extrapulmonary samples.

Methods

Eight Mycobacterium monacense isolates were identified between 2019 and 2023 in the Western Cape province of South Africa. Whole-genome sequencing (WGS) was applied to assess phylogenetic relatedness, identify virulence factors, and characterize the resistome of the isolates. Antimicrobial susceptibility testing (AST) was performed using the GenoType NTM-DR line probe assay (LPA), Sensititre minimum inhibitory concentrations (MIC) plates, and the proportional method based on critical concentrations. Spatial distribution of cases was mapped using ArcGIS software.

Results

Spatiotemporal distribution patterns indicated the presence of circulating clones confined within specific geographical areas. Plasmids coding for ferredoxin and cytochrome P450 genes were identified in one cluster, which notably lacked the chromosomal mbtH gene involved in siderophore biosynthesis for iron acquisition. In contrast, isolates grouped in a second cluster harbored the mbtH chromosomal gene but lacked these plasmid-associated elements. LPA and broth microdilution showed that all Mycobacterium monacense isolates were susceptible to aminoglycosides, fluoroquinolones, and macrolides, but generally exhibited elevated MICs against β-lactam antibiotics. Phenotypic AST indicated that drugs commonly used to treat Mycobacterium tuberculosis complex (MTBC), namely bedaquiline, linezolid, and rifampicin, are effective against Mycobacterium monacense.

Conclusion

Mycobacterium monacense in extrapulmonary cultures accentuates the need for improved diagnostics and enhanced clinical awareness of infections with rare NTM. WGS highlights the potential significance provided by plasmid-encoded genes. Current treatment regimens for MTBC exhibit therapeutic efficacy against Mycobacterium monacense isolates.