Abstract
The arylsulfatase activity of 73 cultures of acid-fast bacilli was studied under a variety of substrate-time combinations. The data indicate that a two-week arylsulfatase test, using tripotassium phenolphthalein disulfate concentrations of 0.0005 M or 0.001 M in Tween-albumin broth, permit differentiation of mammalian and avian tubercle bacilli from all other mycobacteria tested. There also is a suggestion that arylsulfatase activity may be useful in the differential typing of the avian-Battery group of mycobacteria as well as of certain of the rapidly growing acid-fast bacilli,.