GENOTYPING ANALYSIS BY TTC REPEAT DIVERSITY OF M. leprae CLINICAL ISOLATES AND HOUSEHOLD CONTACTS IN LEPROSY ENDEMIC AREA (Genotyping study in Sampang, East Java Province, Indonesia)

Background: East Java is a province where are leprosy endemic pockets. To study the transmission of M.leprae in such areas, a genotyping analysis was done by using TTC triplet in M. leprae genome. Aim and methods: The aim of this study is to analyze the variable number of TTC repeats and distribution in leprosy patients and their household contacts living in Sampang District, East Java Province, Indonesia, where leprosy is highly prevalent. M. leprae DNA was isolated from slit skin smear and nose swab of 16 new untreated leprosy patients and nose swab of 43 household contacts. After amplification of TTC region, the number of repeats was measured by direct sequencing. Results: The numbers of TTC repeat in 16 leprosy patients vary 14-33 with a peak of 14 repeats. Slit skin smear and nose swab showed the same TTC genotype in each patient. Eighteen out of 43 household contacts (41.9%) is found positive TTC variation in length with 13 to 33 repeats. Twelve of them (67%) had the same genotype with their leprosy patients, but remaining 33% had different genotypes. Conclusion: It was concluded that household contacts seems to be exposed not only to M. leprae of patient in the same house but also be exposed to other sources such as patients in other family or non-human environmental source(s). We have to consider closely related 3 factors, agent, host and environmental factors, when we study epidemiology of leprosy.