Mycobacteria are an important group of bacteria which includes pathogens known to cause serious diseases in humans, including tuberculosis (Mycobacterium tuberculosis) and leprosy (Mycobacterium leprae). Whilst the diseases caused by this genus of bacteria can be devastating, there is a positive side to it. Mycobacterium vaccae, is ubiquitous in soil, and exposure to it has been shown to reduce anxiety, and through this effect, the ability to learn.
This is a test for a textile which is impregnated with Mycobacterium vaccae, so that garments made with it would gently expose their wearers to a natural anxiolytic (anti-anxiety medication)and reduce levels of anxiety and stress.
Mycobacteria have an unusual, waxy coating which makes them impervious to standard staining methods, such as the Gram stain. However, the Ziehl–Neelsen stain, also known as the acid-fast stain, is a specially developed stain that can be used on these bacteria. Here some textile swatches impregnated with Mycobacterium vaccae have been stained in this manner to reveal the bacteria. The first stain component carbol fuchsin stains both the bacteria and material but when this is destained with acid-alcohol, the textile loses the dye but the acid-fast bacteria, because of their thick and waxy lipid layer retain the first red dye. When the counter stain is applied, the non-acid-fast material stains blue and the acid-fast bacteria retain the carbol fuchsin and appear red.