01952nas a2200397   4500000000100000008004100001260001300042653001500055653001000070653000900080653002200089653001200111653001500123653001000138653001200148653003100160653001100191653001100202653001400213653001200227653000900239653000900248653001600257653002500273100001500298700001200313700001500325700001000340700001200350700001300362245011800375300001100493490000800504520102800512022001401540       1990                            d  c1990 Dec10aAdolescent10aAdult10aAged10aAged, 80 and over10aAnimals10aCalifornia10aChild10aDapsone10aDrug Resistance, Microbial10aFemale10aHumans10aIncidence10aleprosy10aMale10aMice10aMiddle Aged10aMycobacterium leprae1 aGelber R H1 aRea T H1 aMurray L P1 aSiu P1 aTsang M1 aByrd S R00aPrimary dapsone-resistant Hansen's disease in California. Experience with over 100 Mycobacterium leprae isolates.  a1584-60 v1263 a<p>We found that in the years 1978 through 1981 only one of 54 previously untreated patients with Hansen's disease was found to harbor dapsone-resistant Mycobacterium leprae. That single strain was only partially resistant, ie, it was resistant to 0.0001% dapsone in a mouse diet but not to higher concentrations. During the years 1983 through 1988, M leprae from 47 previously untreated patients presenting to clinics in San Francisco, Calif, and Los Angeles, Calif, grew in mice. None of these strains was found to be dapsone resistant. Thus, from 1978 through 1988 only one of 101 M leprae isolates obtained from skin biopsy specimens from patients with leprosy was found to be resistant to dapsone. We have concluded that primary dapsone resistance still does not appear to be a significant problem in California. Owing to the fact that our single resistant case and those reported from international sources are, in general, partially resistant, the potential importance of partial dapsone resistance is discussed.</p>  a0003-987X