title: Evaluation of a rapid radiometric differentiation test for the Mycobacterium tuberculosis complex by selective inhibition with p-nitro-alpha-acetylamino-beta-hydroxypropiophenone.
abstract: This study is an evaluation of a rapid technique for the differentiation of the Mycobacterium tuberculosis complex from other mycobacteria, using p-nitro-alpha-acetylamino-beta- hydroxypropiophenone (NAP) as a selective inhibitory agent. A total of 416 coded cultures, 234 cultures belonging to the M. tuberculosis complex and 182 cultures belonging to 35 other mycobacterial species, were tested in two laboratories for p-nitro-alpha-acetylamino-beta- hydroxypropiophenone inhibition to concentrations of 5 and 10 micrograms of NAP per ml in Middlebrook 7H12 liquid medium. Two testing modes were compared: the indirect, in which a large bacterial inoculum was used from an isolated culture on a solid medium, and the direct, which used a small inoculum from 7H12 medium. A decrease or no increase in daily 14CO2 output as measured by a BACTEC system was considered evidence of inhibition. The data presented show that a concentration of 5 micrograms of NAP per ml can effectively separate the M. tuberculosis complex from other mycobacterial species in 4 to 6 days. The direct test data show that, unlike other conventional biochemical tests, it does not require a heavy inoculum of mycobacteria and can therefore be performed soon after growth is detected by the radiometric method.
mesh_terms: D001431:Bacteriological Techniques; D005069:Evaluation Studies as Topic; D006910:Hydroxypropiophenone / Q000031:analogs & derivatives*; D009169:Mycobacterium tuberculosis / Q000145:classification* / Q000187:drug effects; D009170:Nontuberculous Mycobacteria / Q000145:classification / Q000187:drug effects; D011427:Propiophenones / Q000494:pharmacology*; D011874:Radiometry; D013997:Time Factors
chemical_list: D011427:Propiophenones; D006910:Hydroxypropiophenone; C017561:4-nitro-alpha-acetylamino-beta-hydroxypropiophenone