01193nas a2200121   4500000000100000008004100001100001400042700001600056245009500072300001200167490000600179520088600185       1971                            d1 aMcRae D H1 aShepard C C00aRelationship Between the Staining Quality of Mycobacterium leprae and Infectivity for Mice  a116-1200 v33 aThe proposal has been made that only solidly staining forms of Mycobacteriwn
leprae are viable. On the basis of a previous study, solidly staining bacilli were defined
as those that stained completely and darkly throughout their length. A study
was carried out to correlate the proportion of solidly staining bacilli in inocula with
the infectivity and rate of appearance of bacillary growth in inoculated mice. The
inocula originated in skin biopsy specimens of patients and in mouse passage material;
there were 347 inocula suitable for study. The rate of appearance of bacillary
growth in inoculated mice confirmed the hypothesis that nonsolid bacilli are inert
and nonviable and that all growth originates from the solidly staining organisms.
The minimal infectious dose was determined in four suspensions and was found to
range from 40 to 3 solidly staining bacilli.