Autotransporters Drive Biofilm Formation and Autoaggregation in the Diderm Firmicute Veillonella parvula.

The are a clade of the that have retained the ancestral diderm character and possess an outer membrane. One of the best studied , , is an anaerobic commensal and opportunistic pathogen inhabiting complex human microbial communities, including the gut and the dental plaque microbiota. Whereas the adhesion and biofilm capacities of are expected to be crucial for its maintenance and development in these environments, studies of adhesion have been hindered by the lack of efficient genetic tools to perform functional analyses in this bacterium.

Leptospira interrogans Retains Direct Virulence After Long Starvation in Water.

Mostly studied as a zoonosis, leptospirosis is also an environment-borne infection and most human cases originate from soil or water contaminations. Yet, only few studies have been interested in the survival of pathogenic Leptospira in freshwater. In this study, water microcosms were designed to evaluate the survival and virulence of Leptospira spp.

The zoonotic pathogen Leptospira interrogans mitigates environmental stress through cyclic-di-GMP-controlled biofilm production.

The zoonotic bacterium Leptospira interrogans is the aetiological agent of leptospirosis, a re-emerging infectious disease that is a growing public health concern. Most human cases of leptospirosis result from environmental infection. Biofilm formation and its contribution to the persistence of virulent leptospires in the environment or in the host have scarcely been addressed.

A systematic review of Leptospira in water and soil environments.

Background: Leptospirosis, caused by pathogenic Leptospira, is a zoonosis of global distribution. This infectious disease is mainly transmitted by indirect exposure to urine of asymptomatic animals via the environment. As human cases generally occur after heavy rain, an emerging hypothesis suggests that rainfall re-suspend leptospires together with soil particles.

Biodiversity of Environmental : Improving Identification and Revisiting the Diagnosis.

Leptospirosis is an important environmental disease and a major threat to human health causing at least 1 million clinical infections annually. There has recently been a growing interest in understanding the environmental lifestyle of . However, isolation from complex environmental samples is difficult and time-consuming and few tools are available to identify isolates at the species level.

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

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.

Continuous Excretion of Ballum in Mice Assessed by Viability Quantitative Polymerase Chain Reaction.

Rodents are the main reservoir animals of leptospirosis. In this study, we characterized and quantified the urinary excretion dynamics of by infected with 2 × 10 virulent serogroup Ballum. Each micturition was collected separately in metabolic cages, at 12 time points from 7 to 117 days post-infection (dpi).

Seeking the environmental source of Leptospirosis reveals durable bacterial viability in river soils.

Background: Leptospirosis is an important re-emerging infectious disease that affects humans worldwide. Infection occurs from indirect environment-mediated exposure to pathogenic leptospires through contaminated watered environments. The ability of pathogenic leptospires to persist in the aqueous environment is a key factor in transmission to new hosts.