Four spirochetes (F1
, B21, Yale
and AMB6-RJ) were isolated from environmental sources: F1
and B21 from soils of an urban slum community in Salvador (Brazil), Yale
from river water in New Haven, ...Connecticut (USA) and AMB6-RJ from a pond in a horse farm in Rio de Janeiro (Brazil). Isolates were helix-shaped, aerobic, highly motile and non-virulent in a hamster model of infection. Draft genomes of the strains were obtained and analysed to determine the relatedness to other species of the genus
. The analysis of 498 core genes showed that strains F1
/B21 and Yale
/AMB6-RJ formed two distinct phylogenetic clades within the 'Pathogens' group (group I). The average nucleotide identity (ANI) values of strains F1
/B21 and Yale
/AMB6-RJ to other previously described
species were below <84 % and <82 %, respectively, which confirmed that these isolates should be classified as representatives of two novel species. Therefore, we propose
sp. nov. and
sp. nov. as new species in the genus
. The type strains are F1
(=ATCC-TSD-163=KIT0259=CLEP00287) and Yale
(=ATCC-TDS-162=KIT0258=CLEP00288), respectively.
Leptospirosis has emerged as an important urban health problem as slum settlements have expanded worldwide. Yet the dynamics of the environmentally transmitted Leptospira pathogen has not been well ...characterized in these settings. We used a stratified dense sampling scheme to study the dynamics of Leptospira abundance in surface waters from a Brazilian urban slum community. We collected surface water samples during the dry, intermediate and rainy seasons within a seven-month period and quantified pathogenic Leptospira by quantitative PCR (qPCR). We used logistic and linear mixed models to identify factors that explained variation for the presence and concentration of Leptospira DNA. Among 335 sewage and 250 standing water samples, Leptospira DNA were detected in 36% and 34%, respectively. Among the 236 samples with positive results geometric mean Leptospira concentrations were 152 GEq/mL. The probability of finding Leptospira DNA was higher in sewage samples collected during the rainy season when increased leptospirosis incidence occurred, than during the dry season (47.2% vs 12.5%, respectively, p = 0.0002). There was a marked spatial and temporal heterogeneity in Leptospira DNA distribution, for which type of water, elevation, and time of day that samples were collected, in addition to season, were significant predictors. Together, these findings indicate that Leptospira are ubiquitous in the slum environment and that the water-related risk to which inhabitants are exposed is low. Seasonal increases in Leptospira presence may explain the timing of leptospirosis outbreaks. Effective prevention will need to consider the spatial and temporal dynamics of pathogenic Leptospira in surface waters to reduce the burden of the disease.
Display omitted
•Sewage and standing water are a source of pathogenic Leptospira in urban slums.•Leptospira were ubiquitous in this setting, detected in 33% of sampled surface water.•Pathogen concentrations were low (∼150 GEq/mL) in positive surface water samples.•Seasonal leptospirosis risk is associated with increased pathogen detection in water.•Prevention needs to account for the spatiotemporal dynamics of pathogenic Leptospira.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Leptospirosis is an important but neglected bacterial zoonosis that has been largely overlooked in Africa. In this systematic review, we aimed to summarise and compare current knowledge of: (1) the ...geographic distribution, prevalence, incidence and diversity of acute human leptospirosis in Africa; and (2) the geographic distribution, host range, prevalence and diversity of Leptospira spp. infection in animal hosts in Africa.
Following Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, we searched for studies that described (1) acute human leptospirosis and (2) pathogenic Leptospira spp. infection in animals. We performed a literature search using eight international and regional databases for English and non-English articles published between January 1930 to October 2014 that met out pre-defined inclusion criteria and strict case definitions.
We identified 97 studies that described acute human leptospirosis (n = 46) or animal Leptospira infection (n = 51) in 26 African countries. The prevalence of acute human leptospirosis ranged from 2 3% to 19 8% (n = 11) in hospital patients with febrile illness. Incidence estimates were largely restricted to the Indian Ocean islands (3 to 101 cases per 100,000 per year (n = 6)). Data from Tanzania indicate that human disease incidence is also high in mainland Africa (75 to 102 cases per 100,000 per year). Three major species (Leptospira borgpetersenii, L. interrogans and L. kirschneri) are predominant in reports from Africa and isolates from a diverse range of serogroups have been reported in human and animal infections. Cattle appear to be important hosts of a large number of Leptospira serogroups in Africa, but few data are available to allow comparison of Leptospira infection in linked human and animal populations. We advocate a 'One Health' approach to promote multidisciplinary research efforts to improve understanding of the animal to human transmission of leptospirosis on the African continent.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A group of strains representing species of the genus Leptospira , isolated from patients with leptospirosis in Mayotte (Indian Ocean), were previously found to be considerably divergent from other ...known species of the genus Leptospira . This was inferred from sequence analysis of rrs (16S rRNA) and other genetic loci and suggests that they belong to a novel species. Two strains from each serogroup currently identified within this novel species were studied. Spirochaete, aerobic, motile, helix-shaped strains grew well at 30–37 °C, but not at 13 °C or in the presence of 8-azaguanine. Draft genomes of the strains were also analysed to study the DNA relatedness with other species of the genus Leptospira . The new isolates formed a distinct clade, which was most closely related to Leptospira borgpetersenii , in multilocus sequence analysis using concatenated sequences of the genes rpoB , recA , fusA , gyrB , leuS and sucA . Analysis of average nucleotide identity and genome-to-genome distances, which have recently been proposed as reliable substitutes for classical DNA–DNA hybridization, further confirmed that these isolates should be classified as representatives of a novel species. The G+C content of the genomic DNA was 39.5 mol%. These isolates are considered to represent a novel species, for which the name Leptospira mayottensis sp. nov. is proposed, with 200901116 ᵀ (= CIP 110703 ᵀ = DSM 28999 ᵀ) as the type strain.
Exposure to soil or water contaminated with the urine of
-infected animals is the most common way in which humans contract leptospirosis. Entire populations can be at high risk of leptospirosis while ...working in inundated fields, when engaging in aquatic sports, or after periods of heavy rainfall. The risk of infection after contact with these environmental sources depends on the ability of
bacteria to survive, persist, and infect new hosts. Multiple variables such as soil and water pH, temperature, and even environmental microbial communities are likely to shape the environmental conditions needed by the pathogen to persist. Here we review what is known about the environmental phase of the infectious
transmission cycle and identify knowledge gaps that will serve as a guide for future research.
Background. We observed that some patients with clinical leptospirosis supported by positive results of rapid tests were negative for leptospirosis on the basis of our diagnostic gold standard, which ...involves isolation of Leptospira species from blood culture and/or a positive result of a microscopic agglutination test (MAT). We hypothesized that our reference standard was imperfect and used statistical modeling to investigate this hypothesis. Methods. Data for 1652 patients with suspected leptospirosis recruited during three observational studies and one randomized control trial that described the application of culture, MAT, immunofluorescence assay (IFA), lateral flow (LF) and/or PCR targeting the 16S rRNA gene were reevaluated using Bayesian latent class models and random-effects meta-analysis. Results. The estimated sensitivities of culture alone, MAT alone, and culture plus MAT (for which the result was considered positive if one or both tests had a positive result) were 10.5% (95% credible interval CrI, 2.7%—27.5%), 49.8% (95% CrI, 37.6%—60.8%), and 55.5% (95% CrI, 42.9%—67.7%), respectively. These low sensitivities were present across all 4 studies. The estimated specificity of MAT alone (and of culture plus MAT) was 98.8% (95% CrI, 92.8%—100.0%). The estimated sensitivities and specificities of PCR (52.7% 95% CrI, 45.2%— 60.6% and 97.2% 95% CrI, 92.0%—99.8%, respectively), lateral flow test (85.6% 95% CrI, 77.5%—93.2% and 96.2% 95% CrI, 87.7%—99.8%, respectively), and immunofluorescence assay (45.5% 95% CrI, 33.3%—60.9% and 96.8% 95% CrI, 92.8%—99.8%, respectively) were considerably different from estimates in which culture plus MAT was considered a perfect gold standard test. Conclusions. Our findings show that culture plus MAT is an imperfect gold standard against which to compare alterative tests for the diagnosis of leptospirosis. Rapid point-of-care tests for this infection would bring an important improvement in patient care, but their future evaluation will require careful consideration of the reference test(s) used and the inclusion of appropriate statistical models.
Full text
Available for:
BFBNIB, NUK, PNG, UL, UM, UPUK
Leptospirosis is a zoonotic and neglected waterborne disease caused by the pathogenic helical spirochetes. Early diagnosis of leptospirosis remains challenging due to non-specific symptoms and the ...limited availability of rapid point-of-care diagnostic tests. Herein, we present a case where a patient suspected of having COVID-19 was diagnosed with leptospirosis using metagenomic next-generation sequencing (mNGS). This case highlights the potential of mNGS to diagnose leptospirosis in the context of the COVID-19 pandemic.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract
In this study, we genotyped samples from environmental reservoirs (surface water and soil), colonized rat specimens, and cases of human severe leptospirosis from an endemic urban slum in ...Brazil, to determine the molecular epidemiology of pathogenic Leptospira and identify pathways of leptospirosis infection. We identified a well-established population of Leptospira interrogans serovar Copenhageni common to human leptospirosis cases, and animal and environmental reservoirs. This finding provides genetic evidence for a potential environmental spillover pathway for rat-borne leptospirosis through the environment in this urban community and highlights the importance of environmental and social interventions to reduce spillover infections.
Leptospirosis is a potentially life‐threatening zoonosis caused by pathogenic Leptospira and for rapid diagnostics, direct detection is desirable. LipL32 protein is the most suitable biomarker for ...direct detection. DNA aptamers are sought to be generated against LipL32 by Systemic Evolution of Ligands via Exponential Enrichment (SELEX). LepDapt‐5a is the most potent aptamer candidate among all the candidates, as determined by direct Enzyme‐linked Aptasorbent Assay (ELASA). LepDapt‐5a was predicted to form a G‐quadruplex structure as predicted by QGRS Mapper and validated experimentally by direct ELASA. The diagnostic potential of the aptamer was further tested on a direct and sandwich ELASA platform. A LOD of 106 mL‐1 and 105 mL‐1 were estimated by direct and sandwich ELASA platforms, respectively, which are within the range associated with leptospiremia levels. The dot blot assay developed was able to attain a LOD of 104 CFU mL−1 against pathogenic Leptospira, which is also within the leptospiremia level. This is the first‐ever DNA aptamer and hybrid‐heterodimeric aptamer constructed against LipL32. The diagnostic potentiality of the LepDapt‐5a DNA aptamer was proven on three major diagnostic platforms, which are direct ELASA, sandwich ELASA, and aptamer‐based dot assay.
Graphical and Lay Summary
Sandwich ELASA using LipL32‐coated microtiter plate‐based oriented immobilization of LepDapt‐H1a hybrid‐heterodimeric aptamer and biotinylated LepDapt‐5a as the detection agent.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Abstract
Animal-associated microbiotas form complex communities, which play crucial
functions for their host, including susceptibility to infections. Despite
increasing attention to bats as ...reservoirs of zoonotic pathogens, their
microbiota is poorly documented, especially for samples potentially implicated
in pathogen transmission such as urine and saliva. Here, using low-biomass
individual samples, we examined the composition and structure of bacterial
communities excreted by insectivorous bats, focusing on three body habitats
(saliva, urine and faeces). We show that niche specialisation occurs as
bacterial community composition was distinct across body habitats with the
majority of phylotypes being body habitat specific. Our results suggest that
urine harbours more diverse bacterial communities than saliva and faeces and
reveal potentially zoonotic bacteria such as Leptospira,
Rickettsia, Bartonella and
Coxiella in all body habitats. Our study emphasised that,
in addition to the traditional use of gut-associated samples such as faeces,
both urine and saliva are also of interest because of their diverse microbiota
and the potential transmission of pathogenic bacteria. Our results represent a
critical baseline for future studies investigating the interactions between
microbiota and infection dynamics in bats.
Body habitat is a main driver of bacterial community composition in bats with the
majority of phylotypes being body habitat specific and major zoonotic bacteria
excreted in all body habitats.
Graphical Abstract Figure.
Body habitat is a main driver of bacterial community composition in
bats with the majority of phylotypes being body habitat specific and
major zoonotic bacteria excreted in all body habitats.
PDF
