RESUMO
Possible drug resistance in Mycobacterium leprae strains from Venezuela and three other South American countries was surveyed by molecular methods. None of the 230 strains from new leprosy cases exhibited drug resistance-associated mutations. However, two of the three strains from relapsed cases contained dapsone resistance mutations, and one strain also harbored a rifampin resistance mutation. Single nucleotide polymorphism analysis of these strains revealed five subtypes: 3I (73.8%), 4P (11.6%), 1D (6.9%), 4N (6%), and 4O (1.7%).
Assuntos
Mycobacterium leprae/efeitos dos fármacos , Adolescente , Adulto , Idoso , Farmacorresistência Bacteriana , Feminino , Genótipo , Humanos , Hanseníase/tratamento farmacológico , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Mycobacterium leprae/classificação , Mycobacterium leprae/genética , Polimorfismo de Nucleotídeo Único , América do SulRESUMO
Possible drug resistance in Mycobacterium leprae strains from Venezuela and three other South American countries was surveyed by molecular methods. None of the 230 strains from new leprosy cases exhibited drug resistance-associated mutations. However, two of the three strains from relapsed cases contained dapsone resistance mutations, and one strain also harbored a rifampin resistance mutation. Single nucleotide polymorphism analysis of these strains revealed five subtypes: 3I (73.8%), 4P (11.6%), 1D (6.9%), 4N (6%), and 4O (1.7%).
Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto , Pessoa de Meia-Idade , Idoso , América do Sul , Testes de Sensibilidade Microbiana , Polimorfismo de Nucleotídeo Único , Farmacorresistência Bacteriana , Genótipo , Hanseníase/tratamento farmacológico , Mycobacterium leprae/classificação , Mycobacterium leprae/efeitos dos fármacos , Mycobacterium leprae/genéticaRESUMO
Reductive evolution and massive pseudogene formation have shaped the 3.31-Mb genome of Mycobacterium leprae, an unculturable obligate pathogen that causes leprosy in humans. The complete genome sequence of M. leprae strain Br4923 from Brazil was obtained by conventional methods (6x coverage), and Illumina resequencing technology was used to obtain the sequences of strains Thai53 (38x coverage) and NHDP63 (46x coverage) from Thailand and the United States, respectively. Whole-genome comparisons with the previously sequenced TN strain from India revealed that the four strains share 99.995% sequence identity and differ only in 215 polymorphic sites, mainly SNPs, and by 5 pseudogenes. Sixteen interrelated SNP subtypes were defined by genotyping both extant and extinct strains of M. leprae from around the world. The 16 SNP subtypes showed a strong geographical association that reflects the migration patterns of early humans and trade routes, with the Silk Road linking Europe to China having contributed to the spread of leprosy.
Assuntos
Genoma Bacteriano , Hanseníase/microbiologia , Mycobacterium leprae/genética , Filogenia , Genes Bacterianos , Geografia , Humanos , Hanseníase/genética , Mycobacterium leprae/classificação , Polimorfismo de Nucleotídeo Único , Recombinação GenéticaRESUMO
Comparative genomics analysis of the Tamil Nadu strain of Mycobacterium leprae has uncovered several polymorphic sites with potential as epidemiological tools. In this study we compared the stability of two different markers of genomic biodiversity of M. leprae in several biopsy samples isolated from the same leprosy patient. The first type comprises five different variable-number tandem repeats (VNTR), while the second is composed of three single nucleotide polymorphisms (SNP). Contrasting results were obtained, since no variation was seen in the SNP profiles of M. leprae from 42 patients from 7 different locations in Mali whereas the VNTR profiles varied considerably. Furthermore, since variation in the VNTR pattern was seen not only between different isolates of M. leprae but also between biopsy samples from the same patient, these VNTR may be too dynamic for use as epidemiological markers for leprosy.
Assuntos
Técnicas de Tipagem Bacteriana/métodos , DNA Bacteriano/genética , Repetições Minissatélites , Mycobacterium leprae/classificação , Mycobacterium leprae/genética , Adulto , Idoso , Alelos , Primers do DNA/genética , Feminino , Humanos , Hanseníase/microbiologia , Masculino , Mali , Pessoa de Meia-Idade , Epidemiologia Molecular , Mycobacterium leprae/isolamento & purificação , Polimorfismo Genético , Polimorfismo de Nucleotídeo ÚnicoRESUMO
In addition to multidrug therapy, elimination of leprosy requires improved diagnostic methods. Using a comparative genomics approach, 17 potential protein antigens (MLP) that are restricted to Mycobacterium leprae, or of limited distribution, were produced and tested for antigen-specific immune responses on leprosy patients, healthy contacts of leprosy patients, and tuberculosis patients in Mali and Bangladesh, as well as on non-endemic controls. T-cell antigenicity of MLP was confirmed by IFN-gamma production in whole-blood assays with the highest responses observed in paucibacillary leprosy patients and healthy contacts. Four MLP behaved well in both countries and induced significantly different responses between the study groups. Peptides carrying T cell epitopes from one of the antigens gave promising results in restimulation assays in mice and immune responses were not influenced by prior exposure to BCG or environmental mycobacteria. This study provides the immunological framework for the development of a specific, peptide-based immunodiagnostic test for leprosy.
Assuntos
Testes Imunológicos/métodos , Hanseníase/diagnóstico , Mycobacterium leprae/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Antibacterianos/biossíntese , Antígenos de Bactérias/imunologia , Células Cultivadas , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Interferon gama/biossíntese , Hanseníase/imunologia , Leucócitos Mononucleares/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , Mycobacterium leprae/isolamento & purificação , Peptídeos/imunologia , Linfócitos T/imunologiaRESUMO
Leprosy is an infectious, neurodegenerative disease of humans caused by Mycobacterium leprae. Despite effective control programs, the incidence of leprosy remains stubbornly high, suggesting that transmission may be more common than expected. The rationale of this work was to use bioinformatics and comparative genomics to identify potentially antigenic proteins for diagnostic purposes. This approach defined three classes of proteins: those restricted to M. leprae (class I), those present in M. leprae with orthologues in other organisms besides mycobacteria (class II), and exported or surface-exposed proteins (class III). Twelve genes (two class I, four class II, and six class III proteins) were cloned in Escherichia coli, and their protein products were purified. Six of these proteins were detected in cell extracts of M. leprae by immunoblotting. The immunogenicity of each recombinant protein was then investigated in leprosy patients by measuring the reactivity of circulating antibody and gamma interferon (IFN-gamma) responses in T-cell restimulation assays. Several class II and class III proteins were recognized by circulating antibodies. Importantly, most class II proteins elicited IFN-gamma responses that were significantly stronger than those produced by previously identified antigens. Among them, two class II proteins, ML0308 and ML2498, showed marked humoral and cellular immunogenicity, therefore providing promising candidates for the diagnosis of both tuberculoid and lepromatous forms of leprosy.
Assuntos
Antígenos de Bactérias/imunologia , Genoma Bacteriano , Hanseníase/diagnóstico , Mycobacterium leprae/imunologia , Sequência de Aminoácidos , Anticorpos Antibacterianos/biossíntese , Anticorpos Antibacterianos/sangue , Antígenos de Bactérias/biossíntese , Antígenos de Bactérias/genética , Biologia Computacional , Genes Bacterianos , Humanos , Interferon gama/metabolismo , Hanseníase/sangue , Hanseníase/imunologia , Hanseníase/metabolismo , Dados de Sequência MolecularRESUMO
Leprosy, a chronic human disease with potentially debilitating neurological consequences, results from infection with Mycobacterium leprae. This unculturable pathogen has undergone extensive reductive evolution, with half of its genome now occupied by pseudogenes. Using comparative genomics, we demonstrated that all extant cases of leprosy are attributable to a single clone whose dissemination worldwide can be retraced from analysis of very rare single-nucleotide polymorphisms. The disease seems to have originated in Eastern Africa or the Near East and spread with successive human migrations. Europeans or North Africans introduced leprosy into West Africa and the Americas within the past 500 years.
Assuntos
Emigração e Imigração , Hanseníase/história , Mycobacterium leprae/genética , África/epidemiologia , América/epidemiologia , Ásia/epidemiologia , Evolução Biológica , Europa (Continente)/epidemiologia , Genes Bacterianos , Genoma Bacteriano , História do Século XVIII , História do Século XIX , História Antiga , História Medieval , Humanos , Sequências Repetitivas Dispersas , Hanseníase/epidemiologia , Hanseníase/microbiologia , Hanseníase/transmissão , Repetições Minissatélites , Mycobacterium leprae/classificação , Análise de Sequência com Séries de Oligonucleotídeos , Polimorfismo de Nucleotídeo Único , Dinâmica Populacional , Pseudogenes , Análise de Sequência de DNARESUMO
Leprosy, a chronic human disease with potentially debilitating neurological consequences, results from infection with Mycobacterium leprae. This unculturable pathogen has undergone extensive reductive evolution, with half of its genome now occupied by pseudogenes. Using comparative genomics, we demonstrated that all extant cases of leprosy are attributable to a single clone whose dissemination worldwide can be retraced from analysis of very rare single-nucleotide polymorphisms. The disease seems to have originated in Eastern Africa or the Near East and spread with successive human migrations. Europeans or North Africans introduced leprosy into West Africa and the Americas within the past 500 years.