Reduction of potassium tellurite and ATP content in Mycobacterium leprae

The purpose of this investigation was to examine those properties of Mycobacterium leprae which might be useful in estimating the heterogeneity of the bacterial populations harvested from the tissues of experimentally infected armadillos. The following technical procedures were applied: fluorescent microscopy on smears stained by an Auramine O-Ethidium bromide dual procedure, fine structure observation of ultrathin sections, reduction of potassium tellurite as observed under the electron microscope, and ATP content of the bacteria. The quantitative data from these procedures was compared to the morphological index, and it was shown that the results did not correlate. However, the study of tellurite reduction was interesting because this technique may prove useful in evaluating the contamination of M. leprae preparations by host tissues. More significant was the fact that M. leprae reduced tellurite. Even though the reduction was at a very low efficiency under the conditions described, it would be possible to use this technique to investigate the effects of several substrates on the respiratory activity of the leprosy bacilli.