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Natural environmental water sources in endemic regions of northeastern Brazil are potential reservoirs of viable Mycobacterium leprae.

ABSTRACT: The detection of live Mycobacterium leprae in soil and animals other than humans suggests that the environment plays a role in the transmission of leprosy.The objective of this study was to investigate the presence of viable M. leprae in natural water sources used by the local population in five municipalities in the state of Ceará, northeastern Brazil.Samples were collected from 30 different sources. Viable bacilli were identified by reverse transcriptase polymerase chain reaction (PCR) of the M. leprae gyrA gene and sequencing of the PCR products. Physicochemical properties of each water source were also assessed.M. leprae gyrA mRNA was found in 23 (76.7%) of the water sources. No association was found between depth of the water and sample positivity, nor was there any association between the type of water used by the population and sample positivity. An association between viable M. leprae and temperature and pH was found. Georeferencing showed a relation between the residences of leprosy cases and water source containing the bacterium.The finding of viable M. leprae in natural water sources associated with human contact suggests that the environment plays an important role in maintaining endemic leprosy in the study region.

SUBMITTER: Arraes MLBM

PROVIDER: S-EPMC5719548 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature

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Natural environmental water sources in endemic regions of northeastern Brazil are potential reservoirs of viable Mycobacterium leprae.

Arraes Maria Luisa Bezerra de Macedo MLBM Holanda Maísa Viana de MV Lima Luana Nepomuceno Gondim Costa LNGC Sabadia José Antônio Beltrão JAB Duarte Cynthia Romariz CR Almeida Rosa Livia Freitas RLF Kendall Carl C Kerr Ligia Regina Sansigolo LRS Frota Cristiane Cunha CC

Memorias do Instituto Oswaldo Cruz 20171201 12

<h4>Background</h4>The detection of live Mycobacterium leprae in soil and animals other than humans suggests that the environment plays a role in the transmission of leprosy.<h4>Objective</h4>The objective of this study was to investigate the presence of viable M. leprae in natural water sources used by the local population in five municipalities in the state of Ceará, northeastern Brazil.<h4>Methods</h4>Samples were collected from 30 different sources. Viable bacilli were identified by reverse ...[more]

PMID: 29211240

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Project description:Leprosy is endemic in large part of Brazil with 28,761 new patients in 2015, the second largest number worldwide and reaches 9/10.000 in highly endemic regions and 2.7/10.000 in the city of Fortaleza, Ceará, Northeast Brazil. For better understanding of risk factors for leprosy transmission, we conducted an epidemiologic study supplemented by 17 locus VNTR and SNP 1-4 typing of Mycobacterium leprae in skin biopsy samples from new multibacillary (MB) patients diagnosed at a reference center in 2009 and 2010. Among the 1,519 new patients detected during the study period, 998 (65.7%) were MB and we performed DNA extraction and genotyping on 160 skin biopsy samples, resulting in 159 (16%) good multilocus VNTR types. Thirty-eight of these patients also provided VNTR types from M. leprae in nasal swabs. The SNP-Type was obtained for 157 patients and 87% were of type 4. Upon consideration all VNTR markers, 156 different genotypes and three pairs with identical genotypes were observed; no epidemiologic relation could be observed between individuals in these pairs. Considerable variability in differentiating index (DI) was observed between the different markers and the four with highest DI [(AT)15, (TA)18, (AT)17 and (GAA)21] frequently demonstrated differences in copy number when comparing genotypes from both type of samples. Excluding these markers from analysis resulted in 83 genotypes, 20 of which included 96 of the patients (60.3%). These clusters were composed of two (n = 8), three (n = 6), four (n = 1), five (n = 2), six (n = 1), 19 (n = 1) and 23 (n = 23) individuals and suggests that recent transmission is contributing to the maintenance of leprosy in Fortaleza. When comparing epidemiological and clinical variables among patients within clustered or with unique M. leprae genotypes, a positive bacterial index in skin biopsies and knowledge of working with someone with the disease were significantly associated with clustering. A tendency to belong to a cluster was observed with later notification of disease (mean value of 3.4 months) and having disability grade 2. A tendency for lack of clustering was observed for patients who reported to have lived with another leprosy case but this might be due to lack of inclusion of household contacts in the study. Although clusters were spread over the city, kernel analysis revealed that some of the patients belonging to the two major clusters were spatially related to some neighborhoods that report poverty and high disease incidence in children. Finally, inclusion of genotypes from nasal swabs might be warranted. A major limitation of the study is that sample size of 160 patients from a two year period represents only 15% of the new patients and this could have weakened statistical outcomes. This is the first molecular epidemiology study of leprosy in Brazil and although the high clustering level suggests that recent transmission is the major cause of disease in Fortaleza; the existence of two large clusters needs further investigation.

Project description:BACKGROUND: This study was conducted to analyse M. leprae gene expression profiles in biopsy of leprosy patient and in environmental soil samples. Investigation was carried out to find out the expression profile for the minimal gene set necessary for growth of environmental M. leprae and its genes potentially require for infection and pathogenesis of leprosy. METHOD: RNA was extracted from human biopsy and environmental soil samples and total RNA obtained by subtractive hybridization of rRNA, was reverse transcribed and amplified using random primers. The whole genome was tiled at 10bp to obtain probes having 60 mer oligonucleotides in sense orientation. 179963 probes were designed in both sense and antisense orientation. Blast was performed against the mRNA sequence databases to check the specificity of the probes. Finally, 359926 probes were designed and 56579 specific probes were replicated to fill the remaining spots. RESULTS: Up regulation of several functional genes of M. leprae genome were observed from soil samples responsible for metabolism of Carbon compounds [9], Amino acids and amines [4] , Fatty acids synthesis [21], Lipid Biosynthesis [33], Phosphorous compounds [2]. Up regulation of genes were observed from soil samples in energy metabolism function such as Glycolysis [6], Pyruvate dehydrogenase [1], TCA cycle [12], Glyoxylate bypass [12]. In up regulation of respiration function [11] genes were observed and some of genes responsible for miscellaneous oxidoreductases and oxygenases [22] function, ATP-proton motive force [4] were also observed. Up regulation of genes for cell envelope function [65], conserved membrane proteins [107], cell processes [62], central intermediary metabolism [79], polyamine synthesis[38], biosynthesis of cofactors, prosthetic groups and carriers [36], broad regulatory functions [35], macromolecule metabolism[103], degradation of macromolecules [25], miscellaneous transferases [36], conserved hypothetical [204] and unknowns [101] were observed. Significant up regulation of Virulence genes [9], PE and PPE families [3] were also observed from soil samples. CONCLUSION: Transcriptome analysis indicated that up regulation of essential genes of M. leprae transcripts in environmental samples as compared to M. leprae from human biopsy samples which strongly suggested that several M. leprae genes are expressed more in environment for its survival and may act as source of infection.

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Natural environmental water sources in endemic regions of northeastern Brazil are potential reservoirs of viable Mycobacterium leprae.

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Natural environmental water sources in endemic regions of northeastern Brazil are potential reservoirs of viable Mycobacterium leprae.

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