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Updated: Jun 1, 2026
DNA Fingerprinting of Mycobacterium leprae Strains Using Variable Number Tandem Repeat VNTR - Fragment Length Analysis FLA
Published on: July 15, 2011
Detection of Mycobacterium leprae DNA in clinical and environmental samples using serological analysis and PCR
Ismênia Glauce de Oliveira Barreto da Silveira1, Jorge Alves da Silva Neto1, Jéssica da Silva Ferreira2,3
1Departamento de Ciências Agronômicas e Florestais, Centro de Ciências Vegetais, Universidade Federal Rural do Semi-Árido, Av. Francisco Mota, 572, Costa e Silva, Caixa-postal: 137, Mossoró, RN, CEP 59625-900, Brazil.
Background:
Leprosy is a chronic infectious disease caused by Mycobacterium leprae and persists as a serious public health problem in Brazil. This microorganism is inculturable, making it difficult to diagnose and elucidate details of its transmission chain. Thus, this study aimed to analyze the dynamics of environmental transmission of M. leprae in a case-control study in the city of Mossoró, Brazil.
Methods And Results:
Data of clinical, epidemiological, bacilloscopic, and serological evaluation of 22 newly diagnosed patients were compared, with molecular results of detection of specific genome regions RLEP and 16S rRNA of M. leprae in samples of the nasal swab, saliva, and house dust of these individuals and their controls (44 household contacts and 44 peridomiciliar contacts). The rapid serological tests evaluated, ML flow (IgM ND-O-BSA) and OrangeLife® (IgM and IgG anti NDO-LID 1) showed similar results, with greater positivity among paucibacillaries by OrangeLife® (54.5%). Positivity for nasal swab and saliva in multibacillary patients with RLEP primer was 16.7% and 33.3%, respectively. There was no detection of bacterial DNA in house dust or among paucibacillaries. The OrangeLife® test indicated that the lower the amount of windows, the more transmission in the house (3.79 more chances). Having a history of leprosy cases in the family increased the risk by 2.89 times, and being over 60 years of age gave 3.6 times more chances of acquiring the disease. PCR positivity was higher among all clinical samples using the M. leprae RLEP region than 16S rRNA.
Conclusions:
In this study, the serological and PCR analysis were capable of detecting M. leprae DNA in clinical samples but not in the environmental samples. Close monitoring of patients and household contacts appears an effective measure to reduce the transmission of leprosy in endemic areas.
