Leptospira venezuelensis sp. nov., a new member of the intermediate group isolated from rodents, cattle and humans

Puche, Rafael; Ferrés, Ignacio; Caraballo, L.; Rangel, Yaritza; Picardeau, Mathieu; Takiff, Howard; Iraola, Gregorio

doi:10.1099/ijsem.0.002528

Cited by 37 publications

(26 citation statements)

References 20 publications

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“…The final dataset was composed of available genomes ( n =22, because whole genome sequences for Leptospira idonii were not publicly available, but including the reference genome of Leptospira venezuelensis sp. nov. currently under description by members of our group [ 14 ]) and those sequenced in this study ( n =26).…”

Section: Methodsmentioning

confidence: 99%

Deciphering the unexplored Leptospira diversity from soils uncovers genomic evolution to virulence

et al. 2018

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Despite recent advances in our understanding of the genomics of members of the genus Leptospira, little is known on how virulence has emerged in this heterogeneous bacterial genus as well as on the lifestyle of pathogenic members of the genus Leptospira outside animal hosts. Here, we isolated 12 novel species of the genus Leptospira from tropical soils, significantly increasing the number of known species to 35 and finding evidence of highly unexplored biodiversity in the genus. Extended comparative phylogenomics and pan-genome analyses at the genus level by incorporating 26 novel genomes, revealed that, the traditional leptospiral ‘pathogens’ cluster, as defined by their phylogenetic position, can be split in two groups with distinct virulence potential and accessory gene patterns. These genomic distinctions are strongly linked to the ability to cause or not severe infections in animal models and humans. Our results not only provide new insights into virulence evolution in the members of the genus Leptospira, but also lay the foundations for refining the classification of the pathogenic species.

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Section: Methodsmentioning

confidence: 99%

Deciphering the unexplored Leptospira diversity from soils uncovers genomic evolution to virulence

et al. 2018

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“…Leptospirosis is a life-threatening, zoonotic disease of global importance, with more than 1 million cases and approximately 60,000 deaths estimated annually, predominately in developing tropical countries [ 1 ]. The disease is caused by spirochetes of the genus Leptospira , which contains 35 species, 13 of which in the pathogenic group [ 2 , 3 ]. Pathogenic Leptospira chronically colonize the renal tubules of animal reservoirs and are excreted with the urine.…”

Section: Introductionmentioning

confidence: 99%

Quantification of pathogenic Leptospira in the soils of a Brazilian urban slum

et al. 2018

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BackgroundLeptospirosis is an important zoonotic disease that causes considerable morbidity and mortality globally, primarily in residents of urban slums. While contact with contaminated water plays a critical role in the transmission of leptospirosis, little is known about the distribution and abundance of pathogenic Leptospira spp. in soil and the potential contribution of this source to human infection.Methods/Principal findingsWe collected soil samples (n = 70) from three sites within an urban slum community endemic for leptospirosis in Salvador, Brazil. Using qPCR of Leptospira genes lipl32 and 16S rRNA, we quantified the pathogenic Leptospira load in each soil sample. lipl32 qPCR detected pathogenic Leptospira in 22 (31%) of 70 samples, though the median concentration among positive samples was low (median = 6 GEq/g; range: 4–4.31×102 GEq/g). We also observed heterogeneity in the distribution of pathogenic Leptospira at the fine spatial scale. However, when using 16S rRNA qPCR, we detected a higher proportion of Leptospira-positive samples (86%) and higher bacterial concentrations (median: 4.16×102 GEq/g; range: 4–2.58×104 GEq/g). Sequencing of the qPCR amplicons and qPCR analysis with all type Leptospira species revealed that the 16S rRNA qPCR detected not only pathogenic Leptospira but also intermediate species, although both methods excluded saprophytic Leptospira. No significant associations were identified between the presence of pathogenic Leptospira DNA and environmental characteristics (vegetation, rat activity, distance to an open sewer or a house, or soil clay content), though samples with higher soil moisture content showed higher prevalences.Conclusion/SignificanceThis is the first study to successfully quantify the burden of pathogenic Leptospira in soil from an endemic region. Our results support the hypothesis that soil may be an under-recognized environmental reservoir contributing to transmission of pathogenic Leptospira in urban slums. Consequently, the role of soil should be considered when planning interventions aimed to reduce the burden of leptospirosis in these communities.

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“…Human infection occurs via direct contact between injured skin or mucous membrane with the urine or blood containing the bacteria of the infected animals or due to exposure to bacterial-contaminated soil or water. At present, a total of 10 pathogenic Leptospira and 5 intermediate species have been identified so far and it is likely that novel species will be continuously discovered 6 , 7 . Leptospira could be carried by wide-range animals such as pigs, cattle and dogs, but rodents act as an eminent role in shedding the bacteria into the environment 8 , 9 .…”

Section: Introductionmentioning

confidence: 99%

Geographical and temporal distribution of the residual clusters of human leptospirosis in China, 2005–2016

Dhewantara

Mamun

Zhang

et al. 2018

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Human leptospirosis outbreaks still persistently occur in part of China, indicating that leptospirosis remains an important zoonotic disease in the country. Spatiotemporal pattern of the high-risk leptospirosis cluster and the key characteristics of high-risk areas for leptospirosis across the country are still poorly understood. Using spatial analytical approaches, we analyzed 8,158 human leptospirosis cases notified during 2005–2016 across China to explore the geographical distribution of leptospirosis hotspots and to characterize demographical, ecological and socioeconomic conditions of high-risk counties for leptospirosis in China. During the period studied, leptospirosis incidence was geographically clustered with the highest rate observed in the south of the Province of Yunnan. The degree of spatial clustering decreased over time suggesting changes in local risk factors. However, we detected residual high-risk counties for leptospirosis including counties in the southwest, central, and southeast China. High-risk counties differed from low-risk counties in terms of its demographical, ecological and socioeconomic characteristics. In high-risk clusters, leptospirosis was predominantly observed on younger population, more males and farmers. Additionally, high-risk counties are characterized by larger rural and less developed areas, had less livestock density and crops production, and located at higher elevation with higher level of precipitation compare to low-risk counties. In conclusion, leptospirosis distribution in China appears to be highly clustered to a discrete number of counties highlighting opportunities for elimination; hence, public health interventions should be effectively targeted to high-risk counties identified in this study.

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Leptospira venezuelensis sp. nov., a new member of the intermediate group isolated from rodents, cattle and humans

Cited by 37 publications

References 20 publications

Deciphering the unexplored Leptospira diversity from soils uncovers genomic evolution to virulence

Deciphering the unexplored Leptospira diversity from soils uncovers genomic evolution to virulence

Quantification of pathogenic Leptospira in the soils of a Brazilian urban slum

Geographical and temporal distribution of the residual clusters of human leptospirosis in China, 2005–2016

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