Studies on the effect of starvation on mycobacteria.

Ten cultures of Mycobacterium tuberculosis, one of Mycobacterium kansasii (nonsignificant), and one of Mycobacterium phlei were submitted to starvation. As a result they lost first their acid fastness and then all other staining affinities but, in this chromophobic state, they survived for at least 2 years and, after that time, produced cultures of acid-fast bacilli when transferred onto nutrient media. Chromophobic tubercle bacilli similar to those produced experimentally had previously been demonstrated in caseous lesions of lungs surgically removed from patients under chemotherapy. Since it has been shown that experimentally produced chromophobic bacilli can recover their original biological properties, the opinion is warranted that, under suitable conditions, those in the lung could also become reactivated and cause a relapse of the disease.