title: Use of radiolabelling and fluorescent staining methods in the evaluation of viability and drug susceptibility testing of mycobacterial cultures.
abstract: The utility of radiolabelling and fluorescent staining was investigated for the assessment of viability and drug susceptibility testing of mycobacteria. Fast growing Mycobacterium w was used as a test organism for optimization of experimental conditions. A fairly good correlation was found between the profiles obtained for radiolabelling with 14C-acetate and Fluorescein diacetate-Ethidium bromide (FDA-EB) staining of heat-killed and live M.w. The reliability of two methods for determining the viability of mycobacteria was further established by comparing them with the traditional method of counting of colony forming units (CFU) on solid medium (p less than 0.001). Using radiolabelling and fluorescent staining procedures similar pattern of differential response of M.w was detected against pyrazinamide and rifampicin. This was in agreement with CFU of the cultures. The feasibility of applying these techniques for other mycobacteria was investigated by using Mycobacterium tuberculosis strain H37Ra. The methods could monitor the anti-mycobacterial effect of isoniazid and rifampicin on M. tuberculosis strain H37Ra in shorter duration of time thereby suggesting their use for rapid screening of drugs against slow growing mycobacteria.
mesh_terms: D000085:Acetates / Q000378:metabolism; D019342:Acetic Acid; D002250:Carbon Radioisotopes; D004996:Ethidium; D005452:Fluoresceins; D005456:Fluorescent Dyes; D008826:Microbial Sensitivity Tests / Q000379:methods*; D009161:Mycobacterium / Q000166:cytology / Q000187:drug effects / Q000254:growth & development*; D009169:Mycobacterium tuberculosis / Q000166:cytology / Q000187:drug effects / Q000254:growth & development*; D011865:Radioisotope Dilution Technique
chemical_list: D000085:Acetates; D002250:Carbon Radioisotopes; D005452:Fluoresceins; D005456:Fluorescent Dyes; D004996:Ethidium; D019342:Acetic Acid; C018506:diacetylfluorescein