Exploring Mycobacterium riyadhense: Epidemiology, Clinical Presentation, and Treatment Outcome

Area of Science:

• Medical Microbiology
• Infectious Diseases
• Pulmonology

Background:

• Mycobacterium riyadhense is an emerging nontuberculous mycobacterium (NTM).
• It clinically resembles Mycobacterium tuberculosis (TB), complicating diagnosis and management.
• Nontuberculous mycobacterial infections pose a growing public health challenge.

Purpose of the Study:

• To analyze clinical features and outcomes of Mycobacterium riyadhense infections.
• To compare treatment regimens for M. riyadhense.
• To highlight diagnostic challenges and potential solutions for M. riyadhense.

Main Methods:

• Retrospective analysis of 8 new cases.
• Systematic review of 24 previously reported cases (2009-2025).
• Data extraction on demographics, clinical presentation, diagnostics, treatment, and outcomes.

Main Results:

• Pulmonary infections were common, often misdiagnosed as TB, leading to delays.
• Extrapulmonary manifestations included lymphadenitis and osteomyelitis; a novel association with glomerulonephritis was found.
• Molecular sequencing proved critical for diagnosis; macrolide/fluoroquinolone regimens showed superior outcomes with lower relapse rates.

Conclusions:

• Increased clinical awareness and accurate molecular diagnostics are crucial for M. riyadhense management.
• Targeted antimicrobial therapy, particularly macrolides and fluoroquinolones, improves outcomes.
• Further research is needed to optimize treatment protocols for M. riyadhense infections.