Emergence and Transmission of Drug-/Multidrug-resistant Mycobacterium leprae in a Former Leprosy Colony in the Brazilian Amazon.

BACKGROUND: Leprosy has been treated with multidrug therapy, which has been distributed for free across the globe and regarded as highly efficient. However, the impossibility of growing Mycobacterium leprae in axenic media has historically impaired assessments of M. leprae resistance, a parameter only recently detectable through molecular methods. METHODS: A systematic, population-based search for M. leprae resistance in suspected leprosy relapse cases and contacts was performed in Prata Village, an isolated, hyperendemic, former leprosy colony located in the Brazilian Amazon. Results led to an extended active search involving the entire Prata population. Confirmed leprosy cases were investigated for bacterial resistance using a combination of in vivo testing and direct sequencing of resistance genes folP1, rpoB, and gyrA. A molecular epidemiology analysis was performed using data from 17 variable number tandem repeats (VNTR). RESULTS: Mycobacterium leprae was obtained from biopsies of 37 leprosy cases (18 relapses and 19 new cases): 16 (43.24%) displayed drug-resistance variants. Multidrug resistance to rifampicin and dapsone was observed in 8 relapses and 4 new cases. Single resistance to rifampicin was detected in 1 new case. Resistance to dapsone was present in 2 relapses and 1 new case. Combined molecular resistance and VNTR data revealed evidence of intra-familial primary transmission of resistant M. leprae. CONCLUSIONS: A comprehensive, population-based systematic approach to investigate M. leprae resistance in a unique population revealed an alarming scenario of the emergence and transmission of resistant strains. These findings may be used for the development of new strategies for surveillance of drug resistance in other populations.

Molecular phylogeny of animal pathogen Lacazia loboi inferred from rDNA and DNA coding sequences.

Lacazia loboi is a geographically restricted, uncultivated fungal pathogen of humans and dolphins. Previous investigations using 18S small unit rDNA, chitin synthase 2 and gp43 DNA sequences positioned L. loboi as a close relative of Paracoccidioides brasiliensis. However, given the few individuals of L. loboi studied and the high degree of genetic variation observed in P. brasiliensis, the existence of L. loboi as an independent species has been questioned. To investigate the phylogenetic position of this species, we conducted a phylogenetic analysis using 20 L. loboi collections (L. loboi was obtained from proven cases of lacaziosis and 14 collections were maintained in mice, the others were analyzed from DNA taken directly from infected human tissue.). L. loboi DNA sequence was compared to that from 17 P. brasiliensis strains that represented the known variation in this species, and outgroup taxa in the Onygenales (Ajellomyces and Coccidioides species). Our analyses used DNA sequence from ITS rRNA, and partial coding sequences of chitin synthase 4, ADP-ribosylation factor, and gp43. Nucleotide variation among strains of L. loboi was minor but numerous nucleotide mismatches and multiple gaps were found for these gene regions among members in the Ajellomycetaceae, including P. brasiliensis. Phylogenies inferred using neighbor-joining, maximum parsimony and Bayesian analyses showed no significant conflict and depicted L. loboi as a well-supported, monophyletic group that was sister to the Paracoccidioides clade. These results argue for maintaining L. loboi as a taxon independent from Paracoccidioides within the Ajellomycetaceae.

Potential of AKR1B10 as a Biomarker and Therapeutic Target in Type 2 Leprosy Reaction.

The AKR1B10 (aldo-keto reductase family 1 member B10) gene has important functions in carcinogen-induced neoplasia. AKR1B10 is also expressed in type 2 reaction leprosy patients (R2). We measured the expression of AKR1B10 in the skin lesions of patients with leprosy by immunohistochemistry from biopsies that encompassed the spectrum of types of leprosy, based on the Ridley and Jopling classification [10 samples each of tuberculoid (TT), borderline tuberculoid (BT), mid-borderline (BB), and borderline lepromatous (BL) lesions; four samples of lepromatous lesions (LL)], reactional leprosy [14 samples of type 1 Reaction (R1) and 10 samples of type 2 Reaction (R2)], and biopsies from 9 healthy control (HC) subjects. In addition, 46 lepromatous lesions (BL and LL), 45 lepromatous lesions in regression, and 115 R2 lesions were included. Eight of 10 R2 samples (80%), 3 of 46 active BL and LL samples (6%), 23 of 45 BL and LL samples in regression (51%), and 107 of 115 R2 samples (93%) were positive for AKR1B10, differing significantly between all groups (p < 0.05). AKR1B10 expression was highest in the cytoplasm of macrophages. Thus, AKR1B10 is overexpressed on the lepromatous side (BL and LL) in samples that are in regression, especially type 2 reaction-associated lesions, rendering it a potential marker of type 2 reactional episodes of leprosy and a target of drugs against reactional episodes.

Differential Expression of MicroRNAs in Leprosy Skin Lesions.

Leprosy, a chronic infectious disease caused by Mycobacterium leprae, is a major public health problem in poor and developing countries of the Americas, Africa, and Asia. MicroRNAs (miRNAs), which are small non-coding RNAs (18-24 nucleotides), play an important role in regulating cell and tissue homeostasis through translational downregulation of messenger RNAs (mRNAs). Deregulation of miRNA expression is important for the pathogenesis of various neoplastic and non-neoplastic diseases and has been the focus of many publications; however, studies on the expression of miRNAs in leprosy are rare. Herein, an extensive evaluation of differentially expressed miRNAs was performed on leprosy skin lesions using microarrays. Leprosy patients, classified according to Ridley and Jopling's classification or reactional states (R1 and R2), and healthy controls (HCs) were included. Punch biopsies were collected from the borders of leprosy lesions (10 tuberculoid, 10 borderline tuberculoid, 10 borderline borderline, 10 borderline lepromatous, 4 lepromatous, 14 R1, and 9 R2) and from 9 HCs. miRNA expression profiles were obtained using the Agilent Microarray platform with miRBase, which consists of 1,368 Homo sapiens (hsa)-miRNA candidates. TaqMan quantitative real-time reverse transcription polymerase chain reaction (RT-PCR) was used to validate differentially expressed miRNAs. Sixty-four differentially expressed miRNAs, including 50 upregulated and 14 downregulated (fold change ≥2.0, p-value ≤ 0.05) were identified after comparing samples from patients to those of controls. Twenty differentially expressed miRNAs were identified exclusively in the reactional samples (14 type 1 and 6 type 2). Eight miRNAs were validated by RT-PCR, including seven upregulated (hsa-miR-142-3p, hsa-miR-142-5p, hsa-miR-146b-5p, hsa-miR-342-3p, hsa-miR-361-3p, hsa-miR-3653, and hsa-miR-484) and one downregulated (hsa-miR-1290). These miRNAs were differentially expressed in leprosy and several other diseases, especially those related to the immune response. Moreover, the integration of analysis of validated mi/mRNAs obtained from the same samples allowed target pairs opposite expression pattern of hsa-miRNA-142-3p and AKR1B10, hsa-miRNA-342-3p and FAM180b, and hsa-miRNA-484 and FASN. This study identified several miRNAs that might play an important role in the molecular pathogenesis of the disease. Moreover, these deregulated miRNAs and their respective signaling pathways might be useful as therapeutic markers, therapeutic targets, which could help in the development of drugs to treat leprosy.

Use of sera from humans and dolphins with lacaziosis and sera from experimentally infected mice for Western Blot analyses of Lacazia loboi antigens.

Antibodies in the sera of patients with lacaziosis recognized an approximately 193-kDa antigen and other Lacazia loboi antigens. Paracoccidioides brasiliensis gp43 antigen was detected by all evaluated sera, but they failed to detect a protein with the same molecular mass in L. loboi extracts. This study is the first to examine the humoral response to L. loboi antigens by using multiple host sera.

Correlação clinicopatológica em 40 casos novos de lobomicose / Clinic-pathological correlation in 40 cases of lobomycosis

A lobomicose é micose cutâneo-subcutânea causada pela Lacazia Loboi, fungo não cultivável invitro e de terapêutica insatisfatória, que merece observações clínicas e histopatológicas. O objetivo era correlacionar aspectos clínicos e histopatológicos em 40 casos de lobomicose. Lesões de 40 acreanos com lobomicose foram fotografadas e estudadas histologicamente. Clinicamente, a maioridos pacientes (34/40) apresentava lesões monomórficas queloidiformes, predominantemente nos pavilhões auriculares (18/40). Pontilhados enegrecidos das lesões correlacionavam-se à eliminação transepidérmicas de fungos. Nervos eram íntegros no interior dos granulomas dérmicos. Classificaram-se células histiocitárias de cinco tipos: a. histiócitos isolados contendo fungos; b. histiócitos agrupados em sincício; c. células gigante de corpo estranho; d. células gigantes de langerhans; e. células epitelióides rendilhadas. No interior das células gigantes de corpo estranho e nas formações sinciais, os fungos eram numerosos; ao contrário, nas células gigantes de Langerhans e nas células epitelióides rendilhadas, eram escassos. Conclusões, na lobomicose o fungo multiplica-se muito lentamente, paralelo a deficiência imunológica do hospedeiro humano, traduzida por grandes acúmulhos de fungos, imaturidade das células gigantes, pequeno número de linfócitos, raros granulomas tuberculóides típicos e ineficiência na eliminação fos fungos mortos