Abstract
The universal sample processing multipurpose methodology was not developed for the diagnosis of tuberculosis.
We have recently described a sputum specimen processing method that involved homogenization and decontamination of the specimens by a treatment with dithiothreitol [(2S,3S)-1,4-bis-sulfanilbutan-2,3-diol] [1, 2]. This enable a highly sensitive smear microscopy and a better isolation of M. tuberculosis, showing, for the first time, the usefulness of dithiothreitol in TB laboratories. This report describes a study which was carried out to determine the effects of centrifugal force and centrifugation time on the concentration of mycobacteria in clinical specimens liquefied with dithiothreitol.
The effect of increasing centrifugal force was evaluated by AFB smear sensitivity in a study of 80 sputa that contained AFB, picked from routine submissions, and also by recovery rates of M. tuberculosis from sputa, in this case we performed 10 determinations using AFB smear negative sputa that were sterilized and artificially seeded with known concentrations of Mycobacterium tuberculosis, strain H37Rv.