In a detailed clinical investigation, GenPath Africa colleagues Christoffel Opperman, Sarishna Singh, and Yonas Ghebrekristos from the National Health Laboratory Service (NHLS), along with Robin Warren and Wynand Goosen from Stellenbosch University, explored the complex diagnostic and treatment challenges faced when a patient is infected with multiple types of nontuberculous mycobacteria (NTM).

What is this publication about?

This case study follows the journey of a 40-year-old HIV-positive patient who presented with severe respiratory symptoms and significant weight loss. Using advanced diagnostic tools—including Sanger sequencing, Deeplex Myc-TB, and targeted long-read sequencing (Oxford Nanopore)—the researchers identified a "mixture" of three different NTM species: Mycobacterium kansasii, Mycobacterium chelonae, and Mycobacterium avium. The study specifically highlights how standard laboratory tests can sometimes fail to detect every species present in a mixed infection, potentially leading to incomplete treatment.

Why is this important?

NTMs are opportunistic pathogens widely found in the environment, particularly in water and soil, and can also be transmitted via livestock or contaminated meat. While they are rarely spread from person to person, they pose a major threat to individuals with weakened immune systems. Mixed NTM infections are notoriously difficult to manage because different species often require different antibiotic regimens. This study demonstrates that relying on a single diagnostic target may miss "hidden" pathogens that contribute to disease severity.

How can this make a difference?

By advocating for a multi-target diagnostic approach, this research helps clinicians more accurately identify the specific mix of bacteria causing an infection. It emphasizes the need for personalised treatment strategies that address all pathogenic species present, which is vital for improving survival rates in critically ill patients. Furthermore, the study provides practical recommendations for resource-limited settings—such as using specialized culture media—to help health systems better detect these complex infections even when high-tech sequencing is unavailable.

Christoffel Opperman, Janet Scott, Janre Steyn, Sarishna Singh, Yonas Ghebrekristos, Roland Croxford, Robin Warren, Aliasgar Esmail, Giovanni Ghielmetti, and Wynand Goosen, "Mixed nontuberculous mycobacteria in an immunocompromised patient with probable progressive multifocal leukoencephalopathy." IJID Regions, 2025; 14: 100502. doi:10.1016/j.ijregi.2024.100502.