02507nas a2200325   4500000000100000008004100001260001600042653001100058653001100069653001900080653001100099653001200110653002500122653001700147653003000164653001700194653003200211100001900243700001600262700001500278700001900293700001600312700002100328245009700349856007200446300001000518490000700528520163200535022001402167       2005                            d  c2005 Jun 0110aBiopsy10aBrazil10aDNA, Bacterial10aHumans10aleprosy10aMycobacterium leprae10aNasal Mucosa10apolymerase chain reaction10aRisk Factors10aSensitivity and Specificity1 aPatrocínio LG1 aGoulart IMB1 aGoulart LR1 aPatrocínio JA1 aFerreira FR1 aNegrão Fleury R00aDetection of Mycobacterium leprae in nasal mucosa biopsies by the polymerase chain reaction.  uhttp://onlinelibrary.wiley.com/doi/10.1016/j.femsim.2005.01.002/pdf  a311-60 v443 a<p>Several discoveries about leprosy indicate that Mycobacterium leprae transmission mainly occurs by inhalation, and the nose is major port of entry and exit. The present study evaluated the clinical application of PCR for detection of M. leprae DNA in nasal mucosa biopsies in untreated leprosy patients (52) and their contacts (99) from the State Reference Center in Sanitary Dermatology and Leprosy, Uberlandia, MG, Brazil. PCR detection of a 372-base pair DNA fragment from M. leprae was accomplished in 36 (69.2%) patients, from which 34 (91.9%) of them were multibacillaries. Furthermore, PCR was positive in 3 (16.7%) of 18 slit-skin smear negative, 4 (25.0%) of 16 skin lesion BI negative, 8 (33.3%) of 24 nasal mucosa BI negative patients, and 10 of 99 contacts (10.1%). The presence of bacilli in 10.1% of the contacts may potentially reflect an occult leprosy, and these patients must be accompanied, followed by a chemoprophylaxy treatment. Considering all PCR results against clinical and BI classification of patients and controls, we have found a sensitivity of 69.2%, a specificity of 89.9%, and an accuracy of 82.8%. It has been demonstrated here through PCR of nasal biopsies that the bacillus invades the mucosa, passing through the nasal inferior turbinate to reach peripheral blood. Therefore, the molecular investigation of invasive nasal biopsies by PCR tests has proven to be useful in defining patients of higher risk of transmission and risk-group contacts, which is an important step to reach the World Health Organization objective towards the elimination of leprosy as a public health problem.</p>  a0928-8244