-
International Journal of Infectious... Sep 2020Understanding the nature of Mycobacterium leprae transmission is vital to implement better control strategies for leprosy elimination. The present study expands the...
OBJECTIVES
Understanding the nature of Mycobacterium leprae transmission is vital to implement better control strategies for leprosy elimination. The present study expands the knowledge of county-level strain diversity, distribution, and transmission patterns of leprosy in endemic provinces of China.
METHODS
We genetically characterized 290 clinical isolates of M. leprae from four endemic provinces using variable number tandem repeats (VNTR) and single nucleotide polymorphisms (SNPs). Attained genetic profiles and cluster consequences were contrasted with geographical and migration features of leprosy at county levels.
RESULTS
Considering the allelic variability of 17 VNTR loci by the discriminatory index, (GTA)9, (AT)17, (AT)15, (TA)18, (TTC)21, and (TA)10 are reported to be more highly polymorphic than other loci. The VNTR profile generated the low-density clustering pattern in the counties of Sichuan and Yunnan, whereas clusters have been observed from the isolates from Huayuan (N = 6), Yongding (N = 3), Zixing (N = 3), Chenxi (N = 2) and Zhongfang (N = 2) counties of Hunan, and Zhijin (N = 3), Anlong (N = 2), Zhenning (N = 2), and Xixiu (N = 2) counties of Guizhou. In some clusters, people's social relations have been observed between villages. From the 290 clinical isolates, the most predominantly reported SNP was 3K (278, 95.8%), followed by SNP 1D (10, 3.4%), which are typically observed to be predominant in China. We also detected the novel SNP 3J (2, 0.8%), which has not yet been reported in China.
CONCLUSION
The clustering pattern of M. leprae indicates the transmission of leprosy still persists at county levels, suggesting that there is a need to implement better approaches for tracing the close contacts of leprosy patients.
Topics: Alleles; China; Cluster Analysis; DNA, Bacterial; Genotype; Geography; Humans; Leprosy; Minisatellite Repeats; Molecular Epidemiology; Mycobacterium leprae; Phylogeny; Polymorphism, Single Nucleotide
PubMed: 32553715
DOI: 10.1016/j.ijid.2020.06.032 -
International Journal of Dermatology Aug 2012Mycobacterium leprae was the only known cause of leprosy until 2008, when a new species, named Mycobacterium lepromatosis, was found to cause diffuse lepromatous leprosy...
BACKGROUND
Mycobacterium leprae was the only known cause of leprosy until 2008, when a new species, named Mycobacterium lepromatosis, was found to cause diffuse lepromatous leprosy (DLL), a unique form of leprosy endemic in Mexico.
METHODS
We sought to differentiate the leprosy agents among 120 Mexican patients with various clinical forms of leprosy and to compare their relative prevalences and disease features. Archived skin biopsy specimens from these patients were tested for both M. leprae and M. lepromatosis using polymerase chain reaction-based species-specific assays.
RESULTS
Etiologic species were confirmed in 87 (72.5%) patients, of whom 55 were infected with M. lepromatosis, 18 with M. leprae, and 14 with both organisms. The endemic regions of each agent differed but overlapped. Patients with M. lepromatosis were younger and were distributed across more states; their clinical diagnoses included DLL (n = 13), lepromatous leprosy (LL) (n = 34), and eight other forms of leprosy. By contrast, the diagnoses of patients with M. leprae did not include DLL but did include LL (n = 15) and three other forms of leprosy. Thus, M. lepromatosis caused DLL specifically (P = 0.023). Patients with M. lepromatosis also showed more variable skin lesions; the extremities were the most common sites of biopsy in these patients. Finally, patients with dual infections manifested all clinical forms and accounted for 16.1% of all species-confirmed cases.
CONCLUSIONS
Mycobacterium lepromatosis is another cause of leprosy and is probably more prevalent than M. leprae in Mexico. It mainly causes LL and also specifically DLL. Dual infections caused by both species may occur in endemic areas.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Female; Humans; Leprosy, Lepromatous; Male; Middle Aged; Mycobacterium leprae; Polymerase Chain Reaction; Young Adult
PubMed: 22788812
DOI: 10.1111/j.1365-4632.2011.05414.x -
PLoS Neglected Tropical Diseases Dec 2014Leprosy is a curable neglected disease of humans caused by Mycobacterium leprae that affects the skin and peripheral nerves and manifests clinically in various forms...
Leprosy is a curable neglected disease of humans caused by Mycobacterium leprae that affects the skin and peripheral nerves and manifests clinically in various forms ranging from self-resolving, tuberculoid leprosy to lepromatous leprosy having significant pathology with ensuing disfiguration disability and social stigma. Despite the global success of multi-drug therapy (MDT), incidences of clinical leprosy have been observed in individuals with no apparent exposure to other cases, suggestive of possible non-human sources of the bacteria. In this study we show that common free-living amoebae (FLA) can phagocytose M. leprae, and allow the bacillus to remain viable for up to 8 months within amoebic cysts. Viable bacilli were extracted from separate encysted cocultures comprising three common Acanthamoeba spp.: A. lenticulata, A. castellanii, and A. polyphaga and two strains of Hartmannella vermiformis. Trophozoites of these common FLA take up M. leprae by phagocytosis. M. leprae from infected trophozoites induced to encyst for long-term storage of the bacilli emerged viable by assessment of membrane integrity. The majority (80%) of mice that were injected with bacilli extracted from 35 day cocultures of encysted/excysted A. castellanii and A. polyphaga showed lesion development that was similar to mice challenged with fresh M. leprae from passage mice albeit at a slower initial rate. Mice challenged with coculture-extracted bacilli showed evidence of acid-fast bacteria and positive PCR signal for M. leprae. These data support the conclusion that M. leprae can remain viable long-term in environmentally ubiquitous FLA and retain virulence as assessed in the nu/nu mouse model. Additionally, this work supports the idea that M. leprae might be sustained in the environment between hosts in FLA and such residence in FLA may provide a macrophage-like niche contributing to the higher-than-expected rate of leprosy transmission despite a significant decrease in human reservoirs due to MDT.
Topics: Amoeba; Animals; Coculture Techniques; Humans; Macrophages; Mice; Mice, Nude; Mycobacterium leprae; Phagocytosis; Virulence
PubMed: 25521850
DOI: 10.1371/journal.pntd.0003405 -
Scandinavian Journal of Immunology Apr 2012Although Mycobacterium leprae was the first bacterial pathogen identified causing human disease, it remains one of the few that is non-cultivable. Understanding the... (Review)
Review
Although Mycobacterium leprae was the first bacterial pathogen identified causing human disease, it remains one of the few that is non-cultivable. Understanding the biology of M. leprae is one of the primary challenges in current leprosy research. Genomics has been extremely valuable, nonetheless, functional proteins are ultimately responsible for controlling most aspects of cellular functions, which in turn could facilitate parasitizing the host. Furthermore, bacterial proteins provide targets for most of the vaccines and immunodiagnostic tools. Better understanding of the proteomics of M. leprae could also help in developing new drugs against M. leprae. During the past nearly 15 years, there have been several developments towards the identification of M. leprae proteins employing contemporary proteomics tools. In this review, we discuss the knowledge gained on the biology and pathogenesis of M. leprae from current proteomic studies.
Topics: Animals; Bacterial Proteins; Humans; Leprosy; Mycobacterium leprae; Proteome; Proteomics
PubMed: 22229831
DOI: 10.1111/j.1365-3083.2012.02677.x -
Microbiology Spectrum Jul 2019The mammalian nervous system is invaded by a number of intracellular bacterial pathogens which can establish and progress infection in susceptible individuals.... (Review)
Review
The mammalian nervous system is invaded by a number of intracellular bacterial pathogens which can establish and progress infection in susceptible individuals. Subsequent clinical manifestation is apparent with the impairment of the functional units of the nervous system, i.e., the neurons and the supporting glial cells that produce myelin sheaths around axons and provide trophic support to axons and neurons. Most of these neurotrophic bacteria display unique features, have coevolved with the functional sophistication of the nervous system cells, and have adapted remarkably to manipulate neural cell functions for their own advantage. Understanding how these bacterial pathogens establish intracellular adaptation by hijacking endogenous pathways in the nervous system, initiating myelin damage and axonal degeneration, and interfering with myelin maintenance provides new knowledge not only for developing strategies to combat neurodegenerative conditions induced by these pathogens but also for gaining novel insights into cellular and molecular pathways that regulate nervous system functions. Since the pathways hijacked by bacterial pathogens may also be associated with other neurodegenerative diseases, it is anticipated that detailing the mechanisms of bacterial manipulation of neural systems may shed light on common mechanisms, particularly of early disease events. This chapter details a classic example of neurodegeneration, that caused by , which primarily infects glial cells of the peripheral nervous system (Schwann cells), and how it targets and adapts intracellularly by reprogramming Schwann cells to stem cells/progenitor cells. We also discuss implications of this host cell reprogramming by leprosy bacilli as a model in a wider context.
Topics: Adaptation, Physiological; Animals; Humans; Leprosy; Mycobacterium leprae; Peripheral Nervous System; Schwann Cells
PubMed: 31322104
DOI: 10.1128/microbiolspec.BAI-0020-2019 -
Indian Journal of Dermatology,... 2016Leprosy, a chronic disease caused by Mycobacterium leprae, is a public health concern in certain countries, including India. Although the prevalence of the disease has...
BACKGROUND
Leprosy, a chronic disease caused by Mycobacterium leprae, is a public health concern in certain countries, including India. Although the prevalence of the disease has fallen drastically over time, new cases continue to occur at nearly the same rate in many regions. Several endemic pockets have been observed in India and elsewhere. The precise dynamics of leprosy transmission are still not clearly understood. Both live bacilli as well as M. leprae DNA have been detected in the soil and water of endemic areas; they possibly play an important role in disease transmission.
AIMS
To study the occurrence of viable M. leprae in environmental samples collected from areas of residence of patients with active leprosy.
METHODS
The study was conducted on 169 newly diagnosed leprosy patients in Ghatampur, Uttar Pradesh, India. Soil and water samples were collected from their areas of residence using a standardized protocol. An equal number of soil and water samples were also collected from non-patient areas of the same or adjoining villages. The environmental samples collected from the patients surroundings were subjected to 16S ribosomal RNA gene analysis after obtaining informed consent.
RESULTS
About a quarter of the environmental samples collected from patient areas, (25.4% of soil samples and 24.2% of water samples) were found to be positive for specific 16S ribosomal RNA genes of M. leprae. Environmental samples collected from non-patient areas were all found negative for M. leprae 16S ribosomal RNA genes.
LIMITATIONS
The major limitation of the study was that the sample size was small.
CONCLUSION
The study demonstrated the presence of viable strains of M. leprae in skin smear samples of paucibacillary patients and multibacillary patients, as well as in the environmental samples obtained from around their houses. This could play an important role in the continued transmission of leprosy.
Topics: Adult; Cohort Studies; DNA, Bacterial; Disease Progression; Endemic Diseases; Environmental Monitoring; Female; Humans; Incidence; India; Leprosy; Male; Microbial Viability; Middle Aged; Mycobacterium leprae; Public Health; RNA, Ribosomal, 16S; Risk Assessment; Role; Sampling Studies; Soil Microbiology; Water Pollution
PubMed: 26728806
DOI: 10.4103/0378-6323.168935 -
Nature Communications Jan 2018Leprosy is a chronic human disease caused by the yet-uncultured pathogen Mycobacterium leprae. Although readily curable with multidrug therapy (MDT), over 200,000 new...
Leprosy is a chronic human disease caused by the yet-uncultured pathogen Mycobacterium leprae. Although readily curable with multidrug therapy (MDT), over 200,000 new cases are still reported annually. Here, we obtain M. leprae genome sequences from DNA extracted directly from patients' skin biopsies using a customized protocol. Comparative and phylogenetic analysis of 154 genomes from 25 countries provides insight into evolution and antimicrobial resistance, uncovering lineages and phylogeographic trends, with the most ancestral strains linked to the Far East. In addition to known MDT-resistance mutations, we detect other mutations associated with antibiotic resistance, and retrace a potential stepwise emergence of extensive drug resistance in the pre-MDT era. Some of the previously undescribed mutations occur in genes that are apparently subject to positive selection, and two of these (ribD, fadD9) are restricted to drug-resistant strains. Finally, nonsense mutations in the nth excision repair gene are associated with greater sequence diversity and drug resistance.
Topics: Anti-Infective Agents; Codon, Nonsense; DNA, Bacterial; Drug Resistance, Bacterial; Genome, Bacterial; Humans; Microbial Sensitivity Tests; Mycobacterium leprae; Phylogeny
PubMed: 29367657
DOI: 10.1038/s41467-017-02576-z -
Current Protocols Feb 2022Mycobacterium leprae, the etiologic agent of leprosy, cannot be cultured on artificial media. This characteristic, coupled with its long generation time, presents a...
Mycobacterium leprae, the etiologic agent of leprosy, cannot be cultured on artificial media. This characteristic, coupled with its long generation time, presents a number of unique challenges to studying this pathogen. One of the difficulties facing both researchers and clinicians is the absence of a rapid test to measure the viability of M. leprae in clinical or experimental specimens. The lack of such a tool limits the understanding of M. leprae immunopathogenesis and makes determining the efficacy of drug treatments difficult. With this in mind, we developed a robust two-step molecular viability assay (MVA) that first enumerates the M. leprae in the tissue; then, this data is used to normalize bacterial RNA quantities for the second step, in which the expression of M. leprae esxA and hsp18 are measured. This assay is specific and sensitive enough to be used on most clinical samples. This protocol describes the steps required to extract DNA and RNA from M. leprae-infected tissue, enumerate M. leprae, and measure M. leprae viability based on the normalized expression of two M. leprae-specific genes (hsp18 and esxA). This protocol also outlines an optimal laboratory design and workflow for performing this assay. © 2022 The Leprosy Mission Nepal. Current Protocols published by Wiley Periodicals LLC. This article has been contributed to by US Government employees and their work is in the public domain in the USA. Basic Protocol 1: DNA and RNA P purification from M. leprae-infected tissue Basic Protocol 2: Enumeration of M. leprae by RLEP qPCR on the DNA fraction Basic Protocol 3: Calculation of M. leprae per tissue and normalization of RNA Basic Protocol 4: Reverse-transcription of normalized RNA to generate cDNA Basic Protocol 5: Determination of M. leprae viability using HSP18 and ESXA qPCR on the cDNA Support Protocol 1: M. leprae qPCR primer/probe stock preparation Support Protocol 2: Preparation of plasmid stocks and standard curves.
Topics: DNA, Bacterial; Humans; Leprosy; Mycobacterium leprae; RNA, Bacterial; Real-Time Polymerase Chain Reaction
PubMed: 35113486
DOI: 10.1002/cpz1.359 -
Clinical Microbiology and Infection :... Jan 2014In leprosy, the nasal mucosa is considered as the principal route of transmission for the bacillus Mycobacterium leprae. The objective of this study was to identify M....
In leprosy, the nasal mucosa is considered as the principal route of transmission for the bacillus Mycobacterium leprae. The objective of this study was to identify M. leprae in the oral mucosa of 50 untreated leprosy patients, including 21 paucibacillary (PB) and 29 multibacillary (MB) patients, using immunohistochemistry (IHC), with antibodies against bacillus Calmette-Guérin (BCG) and phenolic glycolipid antigen-1 (PGL-1), and polymerase chain reaction (PCR), with MntH-specific primers for M. leprae, and to compare the results. The material was represented by 163 paraffin blocks containing biopsy samples obtained from clinically normal sites (including the tongue, buccal mucosa and soft palate) and visible lesions anywhere in the oral mucosa. All patients and 158 available samples were included for IHC study. Among the 161 available samples for PCR, 110 had viable DNA. There was viable DNA in at least one area of the oral mucosa for 47 patients. M. leprae was detected in 70% and 78% of patients using IHC and PCR, respectively, and in 94% of the patients by at least one of the two diagnostic methods. There were no differences in detection of M. leprae between MB and PB patients. Similar results were obtained using anti-BCG and anti-PGL-1 antibodies, and immunoreactivity occurred predominantly on free-living bacteria on the epithelial surface, with a predilection for the tongue. Conversely, there was no area of predilection according to the PCR results. M. leprae is present in the oral mucosa at a high frequency, implicating this site as a potential means of leprosy transmission.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Bacterial Proteins; Cation Transport Proteins; Cross-Sectional Studies; Female; Humans; Immunohistochemistry; Leprosy, Multibacillary; Leprosy, Paucibacillary; Male; Middle Aged; Mouth Mucosa; Mycobacterium leprae; Polymerase Chain Reaction; Retrospective Studies; Young Adult
PubMed: 23473290
DOI: 10.1111/1469-0691.12190 -
Emerging Infectious Diseases Jun 2021Mycobacterium leprae was detected by optical microscopy, fluorescent in situ hybridization, and molecular detection in feces collected for the diagnosis of Entamoeba...
Mycobacterium leprae was detected by optical microscopy, fluorescent in situ hybridization, and molecular detection in feces collected for the diagnosis of Entamoeba coli enteritis in a leprosy patient in Burkina Faso. This observation raises questions about the role of fecal excretion of M. leprae in the natural history and diagnosis of leprosy.
Topics: Burkina Faso; Humans; In Situ Hybridization, Fluorescence; Leprosy; Mycobacterium leprae
PubMed: 34013859
DOI: 10.3201/eid2706.200748