Estudo epidemiológico molecular da hanseníase em Fortaleza, Ceará

Abstract

The study of detection of M. leprae DNA in nasal secretions from patients and healthy subjects in addition to the methodologies for genotyping of M. leprae has complemented the leprosy’s epidemiology. This study evaluated the positivity of M. leprae DNA in nasal secretion (NS) of leprosy patients and healthy individuals; and genetic variability among strains of M. leprae, studying the relationship with clinical and epidemiological factors. NS samples were collected from 185 patients (group C), 136 individuals without leprosy (Co) attending the National Reference Center for Sanitary Dermatology Dona Libânia in Fortaleza, Ceará and 121 students from the Faculty Christus in Fortaleza (GE group). Skin biopsies (SB) were collected from 38 individuals in group C. All samples NS were subjected to DNA extraction and amplification of RLEP region by nested PCR. To assess the genetic diversity of M. leprae among individuals, 48 strains of SN positive patients RLEP system were analyzed using the four loci of variable number tandem repeats (VNTRs): AC8b, AC9, and AC8a GT9. To study the variability of the strain in the same individual were compared BP and SN samples of 38 positive patients RLEP system using the fifteen loci VNTRs: AT17, GGT5, GTA9, AC8b, AC8a, AT15, AC9, 21-3, GAA21, TA18, 6-7, 27-5, TA10, 23-3, 12-5. 69.2% of the cases, 66.9% of Co and 28.1% of group GE were positive RLEP. The fact that the individual is male, belonging to socioeconomic class D/E and every year-old age increases the chance in 6,266, 3,083 and 1,046, respectively, be it positive PCR. In the analysis of geographical distribution of individuals positive RLEP, the Co was the group of intersection between C and GE groups and the group C, the smear-positive and positive RLEP were more clustered than smear-positive and negative RLEP. The AC8b, AC9, and AC8a GTA9 loci showed allelic diversity considered moderately discriminating. There was a formation of four groups with strains of identical genotypes. The most common genotypes were AC8b: 8, AC9: 7, AC8a: 8, GTA9: 10 and AC8b: 7, AC9: 8, AC8a: 9, GTA9: 9. Strains of unique genotypes were detected in patients aged greater and in patients in whom there was more time between symptoms and diagnosis. The existence of different strains circulating in the city under study and different subpopulations of bacilli between BP and SN samples of the same individual was observed.