title: Comparison of radiometric macrophage assay and fluorescein diacetate/ethidium bromide staining for evaluation of M. leprae viability.
abstract: Earlier studies from our laboratory reported that a radiometric Mycobacterium leprae resident macrophage assay was a useful in vitro indicator of bacillary viability with good correlation with the established mouse foot pad model. The present study compares our assay with the recently described fluorescein diacetate/ethidium bromide (FDA/EB) method. M. leprae extracted from the dermal lesions of 73 bacilliferous leprosy patients were tested concurrently by both techniques. Good correlation (r = 0.52, p less than 0.001) was found between the radiometric assay evaluating DNA synthesis and the FDA/EB staining reflecting the presence of active esterase enzyme. In addition, the utility of the FDA/EB staining in the monitoring of therapy was established. Twenty-two patients treated for greater than 1 year showed lower numbers of green fluorescing bacilli when compared to 19 untreated or short-term-treated individuals.
mesh_terms: D001431:Bacteriological Techniques; D002478:Cells, Cultured; D004269:DNA, Bacterial / Q000096:biosynthesis; D004996:Ethidium; D005452:Fluoresceins; D006801:Humans; D007918:Leprosy / Q000382:microbiology; D008264:Macrophages / Q000382:microbiology*; D009166:Mycobacterium leprae / Q000254:growth & development* / Q000378:metabolism; D012588:Scintillation Counting; D013194:Staining and Labeling / Q000379:methods*; D013936:Thymidine / Q000378:metabolism
chemical_list: D004269:DNA, Bacterial; D005452:Fluoresceins; D004996:Ethidium; D013936:Thymidine; C018506:diacetylfluorescein