Do acid-fast organisms always suggest serious disease?

Not always. While some acid-fast organisms, such as *Mycobacterium tuberculosis* and *Mycobacterium leprae*, cause severe diseases like tuberculosis and leprosy, others may be present without causing any significant health issues. These are known as non-tuberculous mycobacteria (NTM) and can be found in the environment, such as soil and water. In most cases, NTM infections are not considered a severe threat and can be treated effectively.