Leprosy is still a health problem in Indonesia.The cause of high leprosy rate is still unknown.Therefore it is necessary to know the source, route, and method of transmission of this disease.Researchofmolecular typingis essential to determine and understand the epidemiology of a disease.Recently, the epidemiology of leprosy began to be investigated, about the genotype ofMycobacterium leprae.With this research, leprosy transmission can be controlled more effectively.
Analysis ofMultiple Locus Variable Number of Tandem Repeat(VNTR) was proposed to track the transmission of leprosy based on differences in genetic markers ofMycobacterium leprae.From theMultiple LocusVNTRanalysis,several polymorphisms with potential genetic markers were found to differentiateMycobacterium leprae.However, the spread of polymorphisms varies greatly and depends on the population in each place.Genotypingstudiesrequireslit-skin smears(SSS) or removal of leprosy lesions from the skin.This method is safer than using a skin biopsy.
Research conducted at Dr.Soetomo Surabaya and RSUD Dr.Hasan Sadikin Bandung compared the number of genetic code repeats from genetic markers TTC, AC8a, Ac9, and 6-7 in leprosy patients.There were about 23 patients from RSUD Dr.Soetomo and 21 patients from RSUD Dr.Hasan Sadikin as subjects of this research.All subjects were multibacillary (MB) type leprosy patients, and then the subjects™ DNA was extracted from SSS, followed with PCR (polymerase chain reaction) and genetic analysis for four genetic markers namely TTC, AC8a, AC9, and 6-7.
Mycobacterium lepraeis bacteria that cannot be cultured, so it is sometimes difficult to get enough genetic code from skin smears.Therefore we need a multiplication / amplification technique to get it through the PCR.
The result showed differences in the genotype ofMycobacterium lepraefrom subjects in Surabaya and Bandung.From the 23 subjects in Surabaya, only seven samples had the same repetition of genetic code, and two samples had the same repetition of another genetic code, and only two samples from Bandung had the same knowledge about the repetition of genetic code, and two samples had another genetic code similarity.Then there were only two samples from Surabaya and Bandung that have the same genetic code repetition.
There are variations in the length of repetition of 4 genetic markers studied.TTC genetic markers repeat 12-27 times in samples in Surabaya and 11-50 times in samples in Bandung;AC8a genetic markers (7-11 times from Surabaya samples and 7-10 times from Bandung samples);AC9 genetic markers (8-11 times from Surabaya samples and 10-11 times from Bandung samples);genetic markers 6-7 (6-8 times from Surabaya and Bandung samples).This result is very different from the results of other studies from Brazil, India, and China.Strainsfrom Maharashtra and South India have predominant alleles other than AC8a and 6-7.Whereas in this study, alleles 8 and 6 became predominant alleles.Several other studies foundstrains from China, Brazil, Thailand, and the Philippines, the VNTR locus used (12-5,23-3, 27-5, 6-7, (GTA) 9) has a similarity of dominant alleles except at the locus (AC) 8b, (GGT ) 5, and 21-3 which have different alleles in samples from the Philippines.Some of the results of these studies have found thatmolecular typingis a potential and useful tool for studying thestrain of Mycobacterium leprae.The use of the VNTR locus may be the same in one country, but it differs in each country.
It can be concluded from the research that tested the genetic diversity ofMycobacterium lepraefrom skin smear isolates in leprosy patients in Surabaya and Bandung showed differences in the genetic distribution ofMycobacterium leprae. Analysis ofmultiple locusVNTR showed there was twoMycobacterium lepraeidentical from Surabaya and Bandung.These results support the use of the VNTR locus in research on the transmission ofMycobacterium leprae.Moreover, further research is needed regarding the genetic diversity ofMycobacterium leprae to help determine interventions taken to reduce the number of new cases of leprosy in Indonesia.
Author: Prof. Dr. dr. Cita Rosita Sigit Prakoeswa, Sp.KK, FINS-DV, FAADV
Details of this research available at:
Distribution of Mycobacterium leprae Genotypes from Surabaya and Bandung Clinical Isolates by Multiple Locus Variable Number of Tandem Repeat Analysis
Cita Rosita Sigit Prakoeswa, Bayu Bijaksana Rumondor, Lina Damayanti, Muljaningsih Sasmojo, Dinar Adriaty, Medhi Denisa Alinda, Ratna Wahyuni, M. Yulianto Listiawan, Indropo Agusni,Shinzo Izumi
