RESUMO
Leprosy is a granulomatous infection caused by infection with Mycobacterium leprae or M. lepromatosis. We evaluated skin biopsy and slit skin smear samples from 92 leprosy patients in Colombia by quantitative PCR. Five (5.4%) patients tested positive for M. lepromatosis, providing evidence of the presence of this pathogen in Colombia.
Assuntos
Hanseníase , Mycobacterium , Colômbia/epidemiologia , Humanos , Hanseníase/diagnóstico , Hanseníase/epidemiologia , Hanseníase/microbiologia , Mycobacterium leprae/genéticaRESUMO
BACKGROUND: Mycobacterium leprae was thought to be the exclusive causative agent of leprosy until Mycobacterium lepromatosis was identified in a rare form of leprosy known as diffuse lepromatous leprosy (DLL). METHODS: We isolated M. lepromatosis from a patient with DLL and propagated it in athymic nude mouse footpads. Genomic analysis of this strain (NHDP-385) identified a unique repetitive element, RLPM, on which a specific real-time quantitative polymerase chain reaction assay was developed. The RLPM assay, and a previously developed RLEP quantitative polymerase chain reaction assay for M. leprae, were validated as clinical diagnostic assays according to Clinical Laboratory Improvement Amendments guidelines. We tested DNA from archived histological sections, patient specimens from the United States, Philippines, and Mexico, and US wild armadillos. RESULTS: The limit of detection for the RLEP and RLPM assays is 30 M. leprae per specimen (0.76 bacilli per reaction; coefficient of variation, 0.65%-2.44%) and 122 M. lepromatosis per specimen (3.05 bacilli per reaction; 0.84%-2.9%), respectively. In histological sections (n = 10), 1 lepromatous leprosy (LL), 1 DLL, and 3 Lucio reactions contained M. lepromatosis; 2 LL and 2 Lucio reactions contained M. leprae; and 1 LL reaction contained both species. M. lepromatosis was detected in 3 of 218 US biopsy specimens (1.38%). All Philippines specimens (n = 180) were M. lepromatosis negative and M. leprae positive. Conversely, 15 of 47 Mexican specimens (31.91%) were positive for M. lepromatosis, 19 of 47 (40.43%) were positive for M. leprae, and 2 of 47 (4.26%) contained both organisms. All armadillos were M. lepromatosis negative. CONCLUSIONS: The RLPM and RLEP assays will aid healthcare providers in the clinical diagnosis and surveillance of leprosy.
Assuntos
Mycobacterium leprae , Mycobacterium , Animais , Humanos , México , Camundongos , Mycobacterium leprae/genética , Patologia MolecularRESUMO
A variety of host immunogenetic factors appear to influence both an individual's susceptibility to infection with Mycobacterium leprae and the pathologic course of the disease. Animal models can contribute to a better understanding of the role of immunogenetics in leprosy through comparative studies helping to confirm the significance of various identified traits and in deciphering the underlying mechanisms that may be involved in expression of different disease related phenotypes. Genetically engineered mice, with specific immune or biochemical pathway defects, are particularly useful for investigating granuloma formation and resistance to infection and are shedding new light on borderline areas of the leprosy spectrum which are clinically unstable and have a tendency toward immunological complications. Though armadillos are less developed in this regard, these animals are the only other natural hosts of M. leprae and they present a unique opportunity for comparative study of genetic markers and mechanisms associable with disease susceptibility or resistance, especially the neurological aspects of leprosy. In this paper, we review the recent contributions of genetically engineered mice and armadillos toward our understanding of the immunogenetics of leprosy.
Assuntos
Animais , Camundongos , Animais Geneticamente Modificados , Tatus/genética , Modelos Animais de Doenças , Fenômenos Imunogenéticos/imunologia , Hanseníase/genética , Hanseníase/imunologia , Mycobacterium leprae , Camundongos/genética , Tatus/microbiologia , Mycobacterium leprae/genética , Mycobacterium leprae/imunologiaRESUMO
A variety of host immunogenetic factors appear to influence both an individual's susceptibility to infection with Mycobacterium leprae and the pathologic course of the disease. Animal models can contribute to a better understanding of the role of immunogenetics in leprosy through comparative studies helping to confirm the significance of various identified traits and in deciphering the underlying mechanisms that may be involved in expression of different disease related phenotypes. Genetically engineered mice, with specific immune or biochemical pathway defects, are particularly useful for investigating granuloma formation and resistance to infection and are shedding new light on borderline areas of the leprosy spectrum which are clinically unstable and have a tendency toward immunological complications. Though armadillos are less developed in this regard, these animals are the only other natural hosts of M. leprae and they present a unique opportunity for comparative study of genetic markers and mechanisms associable with disease susceptibility or resistance, especially the neurological aspects of leprosy. In this paper, we review the recent contributions of genetically engineered mice and armadillos toward our understanding of the immunogenetics of leprosy.
Assuntos
Animais Geneticamente Modificados , Tatus/genética , Modelos Animais de Doenças , Fenômenos Imunogenéticos/imunologia , Hanseníase/genética , Hanseníase/imunologia , Camundongos/genética , Mycobacterium leprae , Animais , Tatus/microbiologia , Camundongos/imunologia , Mycobacterium leprae/genética , Mycobacterium leprae/imunologiaAssuntos
Camundongos , Granuloma/imunologia , Granuloma/patologia , Hanseníase/imunologia , Infecções por Mycobacterium/imunologia , Interferon gama/metabolismo , Macrófagos/imunologia , Modelos Imunológicos , Mycobacterium avium , Mycobacterium bovis , Tuberculose Pulmonar/imunologia , Tuberculose Pulmonar/patologia , Óxido Nítrico Sintase/metabolismo , Óxido Nítrico/metabolismoAssuntos
Animais , Animais , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Citocinas/metabolismo , Citometria de Fluxo , Deleção de Genes , Hanseníase/fisiopatologia , Hanseníase/imunologia , Hanseníase/microbiologia , Imuno-Histoquímica , Interferon gama/genética , Linfonodos , /imunologia , /imunologia , Macrófagos Peritoneais/imunologia , Modelos Animais de Doenças , Mycobacterium leprae/crescimento & desenvolvimento , Mycobacterium leprae/imunologia , Mycobacterium leprae/patogenicidade , Pé/microbiologia , Pé/patologiaAssuntos
Antígenos HLA-D/imunologia , Antígenos de Bactérias/imunologia , Antígenos de Bactérias/metabolismo , Apresentação de Antígeno , Camundongos , Citotoxicidade Imunológica , Células Clonais , Células Th1/imunologia , Células Th1/metabolismo , Células Th1/patologia , Células de Schwann/imunologia , Células de Schwann/metabolismo , Células de Schwann/patologia , Epitopos de Linfócito T/imunologia , Hanseníase/etiologia , Hanseníase/imunologia , Hanseníase/patologia , Imunofenotipagem , Mapeamento de Epitopos , Mycobacterium leprae/imunologiaRESUMO
Mycobacterium leprae is uncultivable on artificial medium, but viability can be maintained without multiplication for a limited time in vitro. In this study, we evaluated gamma-irradiation (gamma-irr) as a means to kill this slowly growing organism. Freshly harvested, viable, athymic, nu/nu mouse-derived M. leprae were exposed to varying doses of gamma-irr from a 60Co source. Two indicators of bacterial viability were determined: metabolism, measured by oxidation of 14C-palmitic acid to 14CO2 in the BACTEC 460 system, and multiplication, measured by titration in the mouse foot pad. gamma-Irr of both M. leprae and M. lufu, a cultivable control mycobacterium, resulted in a dose-dependent inhibition of viability. gamma-Irr of up to 10(3) rad had little effect on the metabolic activity of either organism. For M. leprae, 10(4)-10(5) rad caused an intermediate inhibitory effect; whereas 10(6) rad yielded almost total inhibition. In the mouse foot pad assay, up to 10(4) rad had little effect on M. leprae growth; however, 10(5) rad resulted in at least a 2-log reduction in the number of bacilli recovered and no M. leprae growth was measurable after exposure to 10(6) rad. With M. lufu, 10(5) rad inhibited metabolic activity by 99% and caused > or = 2-log reduction in the number of colony forming units (CFU). No CFU of M. lufu were recovered after exposure to 10(6) rad. Scanning electron microscopy revealed the presence of some aberrant protrusions on the cell surface of lethally irradiated M. leprae; whereas boiling and autoclaving caused obvious morphological denaturation. These data suggest that gamma-irr is an effective way to kill M. leprae without causing extensive damage to the cell architecture. Killing M. leprae by gamma-irr may be preferable when comparing cellular responses to live versus dead bacilli in vitro and in vivo.