Which of the following Mycobacterium species is typically found in tap water?

Mycobacterium gordonae is commonly found in tap water, which is important for those working in clinical microbiology to recognize. It is often referred to as the "tap water mycobacterium" and can be isolated from various water sources, including drinking water and water used in other settings like hospitals.

Understanding the environmental reservoirs for different mycobacterial species is essential for distinguishing potential contaminants from clinically significant pathogens. In clinical settings, this species is typically regarded as a nonpathogenic saprophyte, but its presence can complicate the interpretation of cultures, as it may be mistaken for a pathogen in immunocompromised patients or those with underlying lung disease. Identifying contaminants like M. gordonae allows clinicians and microbiologists to better interpret laboratory results and understand the clinical relevance of the organisms isolated during testing.

The other Mycobacterium species mentioned have different ecological niches and are less commonly associated with water sources. For example, M. fortuitum and M. abscessus are more often associated with clinical infections and specific environmental niches, while M. kansasii is mainly linked to specific geographic regions and clinical disease rather than being a general contaminant in tap water.