In search of biomarkers for leprosy by unraveling the host immune response to Mycobacterium leprae.

Mycobacterium leprae, the causative agent of leprosy, is still actively transmitted in endemic areas reflected by the fairly stable number of new cases detected each year. Recognizing the signs and symptoms of leprosy is challenging, especially at an early stage. Improved diagnostic tools, based on sensitive and specific biomarkers, that facilitate diagnosis of leprosy are therefore urgently needed. In this review, we address the challenges that leprosy biomarker research is facing by reviewing cell types reported to be involved in host immunity to M leprae. These cell types can be associated with different possible fates of M leprae infection being either protective immunity, or pathogenic immune responses inducing nerve damage. Unraveling these responses will facilitate the search for biomarkers. Implications for further studies to disentangle the complex interplay between host responses that lead to leprosy disease are discussed, providing leads for the identification of new biomarkers to improve leprosy diagnostics.

High-Resolution Plasma Metabolomics Identifies Alterations in Fatty Acid, Energy, and Micronutrient Metabolism in Adults Across the Leprosy Spectrum.

BACKGROUND: High-resolution metabolomics (HRM) is an innovative tool to study challenging infectious diseases like leprosy, where the pathogen cannot be grown with standard methods. Here, we use HRM to better understand associations between disease manifestations, nutrition, and host metabolism. METHODS: From 2018 to 2019, adults with leprosy and controls were recruited in Minas Gerais, Brazil. Plasma metabolites were detected using an established HRM workflow and characterized by accurate mass, mass to charge ratio m/z and retention time. The mummichog informatics package compared metabolic pathways between cases and controls and between multibacillary (MB) and paucibacillary (PB) leprosy. Additionally, select individual metabolites were quantified and compared. RESULTS: Thirty-nine cases (62% MB and 38% PB) and 25 controls were enrolled. We found differences (P < .05) in several metabolic pathways, including fatty acid metabolism, carnitine shuttle, retinol, vitamin D3, and C-21 steroid metabolism, between cases and controls with lower retinol and associated metabolites in cases. Between MB and PB, leukotrienes, prostaglandins, tryptophan, and cortisol were all found to be lower in MB (P < .05). DISCUSSION: Metabolites associated with several nutrient-related metabolic pathways appeared differentially regulated in leprosy, especially MB versus PB. This pilot study demonstrates the metabolic interdependency of these pathways, which may play a role in the pathophysiology of disease.

Whole mitogenome sequencing uncovers a relation between mitochondrial heteroplasmy and leprosy severity.

BACKGROUND: In recent years, the mitochondria/immune system interaction has been proposed, so that variants of mitochondrial genome and levels of heteroplasmy might deregulate important metabolic processes in fighting infections, such as leprosy. METHODS: We sequenced the whole mitochondrial genome to investigate variants and heteroplasmy levels, considering patients with different clinical forms of leprosy and household contacts. After sequencing, a specific pipeline was used for preparation and bioinformatics analysis to select heteroplasmic variants. RESULTS: We found 116 variants in at least two of the subtypes of the case group (Borderline Tuberculoid, Borderline Lepromatous, Lepromatous), suggesting a possible clinical significance to these variants. Notably, 15 variants were exclusively found in these three clinical forms, of which five variants stand out for being missense (m.3791T > C in MT-ND1, m.5317C > A in MT-ND2, m.8545G > A in MT-ATP8, m.9044T > C in MT-ATP6 and m.15837T > C in MT-CYB). In addition, we found 26 variants shared only by leprosy poles, of which two are characterized as missense (m.4248T > C in MT-ND1 and m.8027G > A in MT-CO2). CONCLUSION: We found a significant number of variants and heteroplasmy levels in the leprosy patients from our cohort, as well as six genes that may influence leprosy susceptibility, suggesting for the first time that the mitogenome might be involved with the leprosy process, distinction of clinical forms and severity. Thus, future studies are needed to help understand the genetic consequences of these variants.

A case report and literature review: Mycobacterium leprae infection diagnosed by metagenomic next-generation sequencing of cerebrospinal fluid.

BACKGROUND: Leprosy is a chronic infectious disease caused by Mycobacterium leprae (M. leprae) that is responsible for deformities and irreversible peripheral nerve damage and has a broad spectrum of clinical and serological manifestations. Leprosy primarily affects the peripheral nerves and rarely presents with central nervous system involvement. Diagnosing leprosy can still be difficult in some cases, especially when the infection involves uncommon clinical manifestations and extracutaneous sites. Delayed diagnosis and treatment of leprosy may lead to irreversible damage and death. CASE PRESENTATION: We report a case of a 30-year-old female presenting with "repeated high fever with symptoms of headache for 14 days". On the day of admission, physical signs of lost eyebrows and scattered red induration patches all over her body were observed. The patient's diagnosis was based on the clinical characteristics using a combination of metagenomic next-generation sequencing (mNGS) of cerebrospinal fluid (CSF) and slit-skin smear. After confirming Listeria meningitis and multibacillary leprosy with erythema nodosum leprosum (ENL), a type 2 reaction, she was treated with ampicillin sodium, dapsone, rifampicin, clofazimine, methylprednisolone, and thalidomide. At the 1-year follow-up, the frequency and severity of headaches have significantly decreased and a good clinical response with improved skin lesions was found. CONCLUSION: This case highlights the importance of considering leprosy, which is a rare and underrecognized disease, in the differential diagnosis of skin rashes with rheumatic manifestations, even in areas where the disease is not endemic, and physicians should be alerted about the possibility of central nervous system infections. In addition, mNGS can be used as a complementary diagnostic tool to traditional diagnostic methods to enhance the diagnostic accuracy of leprosy.

A comparative study on the detection of Mycobacterium leprae DNA in urine samples of leprosy patients using Rlep-PCR with other conventional samples.

BACKGROUND: Mycobacterium leprae causes leprosy that is highly stigmatized and chronic infectious skin disease. Only some diagnostic tools are being used for the identification M. leprae in clinical samples, such as bacillary detection, and histopathological tests. These methods are invasive and often have low sensitivity. Currently, the PCR technique has been used as an effective tool fordetecting M. leprae DNA across different clinical samples. The current study aims to detect M. leprae DNA in urine samples of untreated and treated leprosy patients using the Rlep gene (129 bp) and compared the detection among Ridley-Jopling Classification. METHODS: Clinical samples (Blood, Urine, and Slit Skin Smears (SSS)) were collected from leprosy and Non-leprosy patients. DNA extraction was performed using standard laboratory protocol and Conventional PCR was carried out for all samples using Rlep gene target and the amplicons of urine samples were sequenced by Sanger sequencing to confirm the Rlep gene target. RESULTS: The M. leprae DNA was successfully detected in all clinical samples across all types of leprosy among all the study groups using RLEP-PCR. Rlep gene target was able to detect the presence of M. leprae DNA in 79.17% of urine, 58.33% of blood, and 50% of SSS samples of untreated Smear-Negative leprosy patients. The statistical significant difference (p = 0.004) was observed between BI Negative (Slit Skin Smear test) and RLEP PCR positivity in urine samples of untreated leprosy group. CONCLUSION: The PCR positivity using Rlep gene target (129 bp) was highest in all clinical samples among the study groups, across all types of leprosy. Untreated tuberculoid and PNL leprosy patients showed the highest PCR positivity in urine samples, indicating its potential as a non-invasive diagnostic tool for leprosy and even for contact screening.

Employing advanced computational drug discovery techniques to identify novel inhibitors against ML2640c protein: a potential therapeutic approach for combatting leprosy.

Leprosy, caused by Mycobacterium leprae, remains a significant global health challenge, necessitating innovative approaches to therapeutic intervention. This study employs advanced computational drug discovery techniques to identify potential inhibitors against the ML2640c protein, a key factor in the bacterium's ability to infect and persist within host cells. Utilizing a comprehensive methodology, including virtual screening, re-docking, molecular dynamics simulations, and free energy calculations, we screened a library of compounds for their interaction with ML2640c. Four compounds (24349836, 26616083, 26648979, and 26651264) demonstrated promising inhibitory potential, each exhibiting unique binding energies and interaction patterns that suggest a strong likelihood of disrupting the protein function. The study highlights the efficacy of computational methods in identifying potential therapeutic candidates, presenting compound 26616083 as a notably potent inhibitor due to its excellent binding affinity and stability. Our findings offer a foundation for future experimental validation and optimization, marking a significant step forward in the development of new treatments for leprosy. This research not only advances the fight against leprosy but also showcases the broader applicability of computational drug discovery in tackling infectious diseases.

Novel mutations found in Mycobacterium leprae DNA repair gene nth from central India.

INTRODUCTION: The importance of DNA repair enzymes in maintaining genomic integrity is highlighted by the hypothesis that DNA damage by reactive oxygen/nitrogen species produced inside the host cell is essential for the mutagenesis process. Endonuclease III (Nth), formamidopyrimide (Fpg) and endonuclease VIII (Nei) DNA glycosylases are essential components of the bacterial base excision repair process. Mycobacterium leprae lost both fpg/nei genes during the reductive evolution event and only has the nth (ML2301) gene. This study aims to characterize the mutations in the nth gene of M. leprae strains and explore its correlation with drug-resistance. METHOD: A total of 91 M. leprae positive DNA samples extracted from skin biopsy samples of newly diagnosed leprosy patients from NSCB Hospital Jabalpur were assessed for the nth gene as well as drug resistance-associated loci of the rpoB, gyrA and folP1 genes through PCR followed by Sanger sequencing. RESULTS: Of these 91 patients, a total of two insertion frameshift mutations, two synonymous and seven nonsynonymous mutations were found in nth in seven samples. Sixteen samples were found to be resistant to ofloxacin and one was found to be dapsone resistant as per the known DRDR mutations. No mutations were found in the rpoB region. Interestingly, none of the nth mutations were identified in the drug-resistant associated samples. CONCLUSION: The in-silico structural analysis of the non-synonymous mutations in the Nth predicted five of them were to be deleterious. Our results suggest that the mutations in the nth gene may be potential markers for phylogenetic and epidemiological studies.

Case Report of Leprosy in Central Florida, USA, 2022.

Florida, USA, has witnessed an increased incidence of leprosy cases lacking traditional risk factors. Those trends, in addition to decreasing diagnoses in foreign-born persons, contribute to rising evidence that leprosy has become endemic in the southeastern United States. Travel to Florida should be considered when conducting leprosy contact tracing in any state.

Mycobacterium leprae in Armadillo Tissues from Museum Collections, United States.

We examined armadillos from museum collections in the United States using molecular assays to detect leprosy-causing bacilli. We found Mycobacterium leprae bacilli in samples from the United States, Bolivia, and Paraguay; prevalence was 14.8% in nine-banded armadillos. US isolates belonged to subtype 3I-2, suggesting long-term circulation of this genotype.

Highly sensitive and rapid determination of Mycobacterium leprae based on real-time multiple cross displacement amplification.

BACKGROUND: Mycobacterium leprae (ML) is the pathogen that causes leprosy, which has a long history and still exists today. ML is an intracellular mycobacterium that dominantly induces leprosy by causing permanent damage to the skin, nerves, limbs and eyes as well as deformities and disabilities. Moreover, ML grows slowly and is nonculturable in vitro. Given the prevalence of leprosy, a highly sensitive and rapid method for the early diagnosis of leprosy is urgently needed. RESULTS: In this study, we devised a novel tool for the diagnosis of leprosy by combining restriction endonuclease, real-time fluorescence analysis and multiple cross displacement amplification (E-RT-MCDA). To establish the system, primers for the target gene RLEP were designed, and the optimal conditions for E-RT-MCDA at 67 °C for 36 min were determined. Genomic DNA from ML, various pathogens and clinical samples was used to evaluate and optimize the E-RT-MCDA assay. The limit of detection (LoD) was 48.6 fg per vessel for pure ML genomic DNA, and the specificity of detection was as high as 100%. In addition, the detection process could be completed in 36 min by using a real-time monitor. CONCLUSION: The E-RT-MCDA method devised in the current study is a reliable, sensitive and rapid technique for leprosy diagnosis and could be used as a potential tool in clinical settings.

Leprosy with type 1 reaction in a patient from Ontario, Canada without recent travel misdiagnosed as vasculitic neuropathy: a case report.

BACKGROUND: Leprosy is rare within non-endemic countries such as Canada, where cases are almost exclusively imported from endemic regions, often presenting after an incubation period of as many as 20 years. Due to its rarity and prolonged incubation period, diagnosis is often delayed, which may result in neurologic impairment prior to the initiation of treatment. In this report we describe a case that is novel in its incubation period, which is the longest reported to-date and may have contributed to diagnostic delay. The case also uniquely demonstrates the challenges of distinguishing leprosy reactions from new rheumatologic manifestations in a patient with established autoimmune disease. CASE PRESENTATION: We describe an 84-year-old male patient with rheumatoid arthritis on methotrexate and hydroxychloroquine, with no travel history outside Canada for 56 years, who presented in 2019 with new-onset paresthesias and rash. His paresthesias persisted despite a short course of prednisone, and his rash recurred after initial improvement. He underwent skin biopsy in May 2021, which eventually led to the diagnosis of leprosy. He was diagnosed with type 1 reaction and was started on rifampin, dapsone, clofazimine and prednisone, with which his rash resolved but his neurologic impairment remained. CONCLUSION: This case report serves to highlight the potential for leprosy to present after markedly prolonged incubation periods. This is especially relevant in non-endemic countries that is home to an aging demographic of individuals who migrated decades ago from endemic countries. The importance of this concept is emphasized by the persistent neurologic impairment suffered by our case due to untreated type 1 reaction. We also demonstrate the necessity of skin biopsy in distinguishing this diagnosis from other autoimmune mimics in a patient with known autoimmune disease.

Mycobacterium leprae's Infective Capacity Is Associated with Activation of Genes Involved in PGL-I Biosynthesis in a Schwann Cells Infection Model.

Peripheral nerves and Schwann cells (SCs) are privileged and protected sites for initial colonization, survival, and spread of leprosy bacillus. Mycobacterium leprae strains that survive multidrug therapy show a metabolic inactivation that subsequently induces the recurrence of typical clinical manifestations of leprosy. Furthermore, the role of the cell wall phenolic glycolipid I (PGL-I) in the M. leprae internalization in SCs and the pathogenicity of M. leprae have been extensively known. This study assessed the infectivity in SCs of recurrent and non-recurrent M. leprae and their possible correlation with the genes involved in the PGL-I biosynthesis. The initial infectivity of non-recurrent strains in SCs was greater (27%) than a recurrent strain (6.5%). In addition, as the trials progressed, the infectivity of the recurrent and non-recurrent strains increased 2.5- and 2.0-fold, respectively; however, the maximum infectivity was displayed by non-recurrent strains at 12 days post-infection. On the other hand, qRT-PCR experiments showed that the transcription of key genes involved in PGL-I biosynthesis in non-recurrent strains was higher and faster (Day 3) than observed in the recurrent strain (Day 7). Thus, the results indicate that the capacity of PGL-I production is diminished in the recurrent strain, possibly affecting the infective capacity of these strains previously subjected to multidrug therapy. The present work opens the need to address more extensive and in-depth studies of the analysis of markers in the clinical isolates that indicate a possible future recurrence.

Sensitivity of Mycobacterium leprae to Telacebec.

The treatment of leprosy is long and complex, benefiting from the development of sterilizing, rapidly-acting drugs. Reductive evolution made Mycobacterium leprae exquisitely sensitive to Telacebec, a phase 2 drug candidate for tuberculosis. The unprecedented potency of Telacebec against M. leprae warrants further validation in clinical trials.

Mycobacterium leprae Infection in a Wild Nine-Banded Armadillo, Nuevo León, Mexico.

Nine-banded armadillos (Dasypus novemcinctus) are naturally infected with Mycobacterium leprae and are implicated in the zoonotic transmission of leprosy in the United States. In Mexico, the existence of such a reservoir remains to be characterized. We describe a wild armadillo infected by M. leprae in the state of Nuevo León, Mexico.

Mycobacterium lepromatosis as Cause of Leprosy, Colombia.

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.

Mycobacterium leprae diversity and population dynamics in medieval Europe from novel ancient genomes.

BACKGROUND: Hansen's disease (leprosy), widespread in medieval Europe, is today mainly prevalent in tropical and subtropical regions with around 200,000 new cases reported annually. Despite its long history and appearance in historical records, its origins and past dissemination patterns are still widely unknown. Applying ancient DNA approaches to its major causative agent, Mycobacterium leprae, can significantly improve our understanding of the disease's complex history. Previous studies have identified a high genetic continuity of the pathogen over the last 1500 years and the existence of at least four M. leprae lineages in some parts of Europe since the Early Medieval period. RESULTS: Here, we reconstructed 19 ancient M. leprae genomes to further investigate M. leprae's genetic variation in Europe, with a dedicated focus on bacterial genomes from previously unstudied regions (Belarus, Iberia, Russia, Scotland), from multiple sites in a single region (Cambridgeshire, England), and from two Iberian leprosaria. Overall, our data confirm the existence of similar phylogeographic patterns across Europe, including high diversity in leprosaria. Further, we identified a new genotype in Belarus. By doubling the number of complete ancient M. leprae genomes, our results improve our knowledge of the past phylogeography of M. leprae and reveal a particularly high M. leprae diversity in European medieval leprosaria. CONCLUSIONS: Our findings allow us to detect similar patterns of strain diversity across Europe with branch 3 as the most common branch and the leprosaria as centers for high diversity. The higher resolution of our phylogeny tree also refined our understanding of the interspecies transfer between red squirrels and humans pointing to a late antique/early medieval transmission. Furthermore, with our new estimates on the past population diversity of M. leprae, we gained first insights into the disease's global history in relation to major historic events such as the Roman expansion or the beginning of the regular transatlantic long distance trade. In summary, our findings highlight how studying ancient M. leprae genomes worldwide improves our understanding of leprosy's global history and can contribute to current models of M. leprae's worldwide dissemination, including interspecies transmissions.

Neuropathic ulcers in leprosy: clinical features, diagnosis and treatment.

Leprosy is a neglected disease caused by Mycobacterium leprae and Mycobacterium lepromatosis, and is related to significant disabilities resulting from the neural damage generated by this mycobacteria. Neuropathic ulcers-lesions that can appear at the plantar and extra-plantar levels-are one such disability, and diagnosis requires an adequate dermatological, neurological and microbiological evaluation. The treatment of these lesions is based on a multidisciplinary approach that includes debridement of the necrotic tissue, controlling infections, reducing pressure areas, optimising blood flow, and nerve decompression. This review aims to describe the clinical features, diagnostic methods and treatment of neuropathic ulcers in leprosy. The diagnostic methods and medical management used in leprosy ulcers are based on those used for diabetic foot. This requires radical change as these diseases are immunologically and physiologically very different.

[Epidemiological behavior of leprosy in several Latin American countries, 2011-2020Comportamento epidemiológico da hanseníase em vários países da América Latina, 2011-2020]. / Comportamiento epidemiológico de la lepra en varios países de América Latina, 2011-2020.

Objective: To describe the epidemiological behavior of leprosy in several Latin American countries during 2011-2020, based on World Health Organization (WHO) indicators. Methods: Cross-sectional, descriptive and quantitative study with official data on incidence and prevalence in the general population, children, clinical form and cases with grade 2 disability from WHO records between 2011 and 2020. The eight countries in Latin America that reported most cases were selected and analyses were carried out using simple descriptive and comparative statistics between different variables. Results: During the study period, 301 312 cases of leprosy were reported in the selected countries: Argentina, Brazil, Colombia, Cuba, Dominican Republic, Mexico, Paraguay, and Venezuela. Brazil is the only country in the region with a prevalence greater than 1 per 10 000, representing 93.77% of all cases. Brazil and the Dominican Republic showed an increase in prevalence during 2011-2019, while in other countries the trend was decreasing. The disease is more frequent in men, and multibacillary cases significantly exceed paucibacillary ones. Brazil showed the highest incidences of cases of childhood leprosy and grade 2 disability during the evaluated period. Conclusion: In Latin America, leprosy is only considered a public health problem in Brazil; however, most countries in the region continue to report cases annually, revealing a lack of adequate medical care. This study confirmed the importance of active surveillance, early diagnosis and planning of actions against the disease in all the countries evaluated with the aim of reducing its transmission.

Objetivo: Descrever o comportamento epidemiológico da hanseníase em vários países de América Latina durante 2011-2020, tomando como base os indicadores da Organização Mundial da Saúde (OMS). Método: Estudo transversal, descritivo e quantitativo com dados oficiais de incidência e prevalência na população geral, em crianças, forma clínica e casos com incapacidade de grau 2 nos registros da OMS entre 2011 e 2020. Se selecionaram os oito países da América Latina que relataram a maioria dos casos e as análises foram avaliadas por meio de estatísticas descritivas e comparativas simples entre as variáveis. Resultados: No período, foram notificados 301 312 casos de hanseníase nos países selecionados: Argentina, Brasil, Colômbia, Cuba, México, Paraguai, República Dominicana e Venezuela. O Brasil é o único país da região com prevalência maior que 1 por 10 000 habitantes, representando 93,77% do total de casos. O Brasil e a República Dominicana mostraram um aumento na variação da prevalência durante 2011-2019, enquanto nos demais a tendência foi decrescente. A doença é mais frequente em homens e os casos multibacilares superam significativamente os paucibacilares. O Brasil apresentou as maiores incidências de hanseníase infantil e incapacidade de grau 2 durante o período avaliado. Conclusão: Na América Latina, a hanseníase só é considerada um problema de saúde pública no Brasil; no entanto, a maioria dos países da região continua notificando casos anualmente, revelando falta de assistência médica adequada. O presente estudo confirmou a importância da vigilância ativa, do diagnóstico precoce e do planejamento de ações contra a doença em todos os países avaliados, com o objetivo de reduzir e interromper a sua transmissão.

Fecal Excretion of Mycobacterium leprae, Burkina Faso.

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.

Simultaneous Determination of Mycobacterium leprae Drug Resistance and Single-Nucleotide Polymorphism Genotype by Use of Nested Multiplex PCR with Amplicon Sequencing.

Mycobacterium leprae is the predominant cause of leprosy worldwide, and its genotypes can be classified into four single-nucleotide polymorphism (SNP) types and 16 subtypes. Determining M. leprae drug resistance and genotype is typically done by PCR and Sanger DNA sequencing, which require substantial effort. Here, we describe a rapid method involving multiplex PCR in combination with nested amplification and next-generation sequence analysis that allows simultaneous determination of M. leprae drug resistance and SNP genotype directly from clinical specimens. We used this method to analyze clinical samples from two paucibacillary, nine multibacillary, and six type-undetermined leprosy patients. Regions in folP1, rpoB, gyrA, and gyrB that determine drug resistance and those for 84 SNP-InDels in the M. leprae genome were amplified from clinical samples and their sequences determined. The results showed that seven samples were subtype 1A, three were 1D, and seven were 3K. Three samples of the subtype 3K had folp1 mutation. The method may allow more rapid genetic analyses of M. leprae in clinical samples.