The unique Legionella longbeachae capsule favors intracellular replication and immune evasion.

Legionella longbeachae and Legionella pneumophila are the most common causative agents of Legionnaires' disease. While the clinical manifestations caused by both species are similar, species-specific differences exist in environmental niches, disease epidemiology, and genomic content. One such difference is the presence of a genomic locus predicted to encode a capsule.

The respiratory tract microbiome, the pathogen load, and clinical interventions define severity of bacterial pneumonia.

Bacterial pneumonia is a considerable problem worldwide. Here, we follow the inter-kingdom respiratory tract microbiome (RTM) of a unique cohort of 38 hospitalized patients (n = 97 samples) with pneumonia caused by Legionella pneumophila. The RTM composition is characterized by diversity drops early in hospitalization and ecological species replacement.

Legionella para-effectors target chromatin and promote bacterial replication.

Legionella pneumophila replicates intracellularly by secreting effectors via a type IV secretion system. One of these effectors is a eukaryotic methyltransferase (RomA) that methylates K14 of histone H3 (H3K14me3) to counteract host immune responses. However, it is not known how L.

Genomic erosion and horizontal gene transfer shape functional differences of the ExlA toxin in spp.

Two-partner secretion (TPS) is widespread in the bacterial world. The pore-forming TPS toxin ExlA of is conserved in pathogenic and environmental . While and displayed ExlA-dependent killing, did not cause damage to eukaryotic cells.

Translocated Legionella pneumophila small RNAs mimic eukaryotic microRNAs targeting the host immune response.

Legionella pneumophila is an intracellular bacterial pathogen that can cause a severe form of pneumonia in humans, a phenotype evolved through interactions with aquatic protozoa in the environment. Here, we show that L. pneumophila uses extracellular vesicles to translocate bacterial small RNAs (sRNAs) into host cells that act on host defence signalling pathways.

Reverting the mode of action of the mitochondrial FF-ATPase by preserves its replication niche.

the causative agent of Legionnaires' disease, a severe pneumonia, injects via a type 4 secretion system (T4SS) more than 300 proteins into macrophages, its main host cell in humans. Certain of these proteins are implicated in reprogramming the metabolism of infected cells by reducing mitochondrial oxidative phosphorylation (OXPHOS) early after infection. Here.

Persistent Legionnaires' Disease and Associated Antibiotic Treatment Engender a Highly Disturbed Pulmonary Microbiome Enriched in Opportunistic Microorganisms.

Despite the importance of pneumonia to public health, little is known about the composition of the lung microbiome during infectious diseases, such as pneumonia, and how it evolves during antibiotic therapy. To study the possible relation of the pulmonary microbiome to the severity and outcome of this respiratory disease, we analyzed the dynamics of the pathogen and the human lung microbiome during persistent infections caused by the bacterium and their evolution during antimicrobial treatment. We collected 10 bronchoalveolar lavage fluid samples from three patients during long-term hospitalization due to pneumonia and performed a unique longitudinal study of the interkingdom microbiome, analyzing the samples for presence of bacteria, archaea, fungi, and protozoa by high-throughput Illumina sequencing of marker genes.

More than 18,000 effectors in the genus genome provide multiple, independent combinations for replication in human cells.

The genus comprises 65 species, among which is a human pathogen causing severe pneumonia. To understand the evolution of an environmental to an accidental human pathogen, we have functionally analyzed 80 genomes spanning 58 species. Uniquely, an immense repository of 18,000 secreted proteins encoding 137 different eukaryotic-like domains and over 200 eukaryotic-like proteins is paired with a highly conserved type IV secretion system (T4SS).

Correction: Dynamics and impact of homologous recombination on the evolution of Legionella pneumophila.

[This corrects the article DOI: 10.1371/journal.pgen.

Dynamics and impact of homologous recombination on the evolution of Legionella pneumophila.

Legionella pneumophila is an environmental bacterium and the causative agent of Legionnaires' disease. Previous genomic studies have shown that recombination accounts for a high proportion (>96%) of diversity within several major disease-associated sequence types (STs) of L. pneumophila.

The Legionella pneumophila genome evolved to accommodate multiple regulatory mechanisms controlled by the CsrA-system.

The carbon storage regulator protein CsrA regulates cellular processes post-transcriptionally by binding to target-RNAs altering translation efficiency and/or their stability. Here we identified and analyzed the direct targets of CsrA in the human pathogen Legionella pneumophila. Genome wide transcriptome, proteome and RNA co-immunoprecipitation followed by deep sequencing of a wild type and a csrA mutant strain identified 479 RNAs with potential CsrA interaction sites located in the untranslated and/or coding regions of mRNAs or of known non-coding sRNAs.

Multiple major disease-associated clones of Legionella pneumophila have emerged recently and independently.

Legionella pneumophila is an environmental bacterium and the leading cause of Legionnaires' disease. Just five sequence types (ST), from more than 2000 currently described, cause nearly half of disease cases in northwest Europe. Here, we report the sequence and analyses of 364 L.

Comparative analyses of Legionella species identifies genetic features of strains causing Legionnaires' disease.

Background: The genus Legionella comprises over 60 species. However, L. pneumophila and L.

Legionella pneumophila effector RomA uniquely modifies host chromatin to repress gene expression and promote intracellular bacterial replication.

Histone posttranslational modifications control eukaryotic gene expression and regulate many biological processes including immunity. Pathogens alter host epigenetic control to aid pathogenesis. We find that the intracellular bacterial pathogen Legionella pneumophila uses a Dot/Icm type IV secreted effector, RomA, to uniquely modify the host chromatin landscape.

Reductive evolution in Streptococcus agalactiae and the emergence of a host adapted lineage.

Background: During host specialization, inactivation of genes whose function is no more required is favored by changes in selective constraints and evolutionary bottlenecks. The Gram positive bacteria Streptococcus agalactiae (also called GBS), responsible for septicemia and meningitis in neonates also emerged during the seventies as a cause of severe epidemics in fish farms. To decipher the genetic basis for the emergence of these highly virulent GBS strains and of their adaptation to fish, we have analyzed the genomic sequence of seven strains isolated from fish and other poikilotherms.

Deep sequencing defines the transcriptional map of L. pneumophila and identifies growth phase-dependent regulated ncRNAs implicated in virulence.

The bacterium Legionella pneumophila is found ubiquitously in aquatic environments and can cause a severe pneumonia in humans called Legionnaires' disease. How this bacterium switches from intracellular to extracellular life and adapts to different hosts and environmental conditions is only partly understood. Here we used RNA deep sequencing from exponentially (replicative) and post exponentially (virulent) grown L.

Comparative and functional genomics of legionella identified eukaryotic like proteins as key players in host-pathogen interactions.

Although best known for its ability to cause severe pneumonia in people whose immune defenses are weakened, Legionella pneumophila and Legionella longbeachae are two species of a large genus of bacteria that are ubiquitous in nature, where they parasitize protozoa. Adaptation to the host environment and exploitation of host cell functions are critical for the success of these intracellular pathogens. The establishment and publication of the complete genome sequences of L.

Extensive recombination events and horizontal gene transfer shaped the Legionella pneumophila genomes.

Background: Legionella pneumophila is an intracellular pathogen of environmental protozoa. When humans inhale contaminated aerosols this bacterium may cause a severe pneumonia called Legionnaires' disease. Despite the abundance of dozens of Legionella species in aquatic reservoirs, the vast majority of human disease is caused by a single serogroup (Sg) of a single species, namely L.

Double-stranded RNA adenosine deaminase ADAR-1-induced hypermutated genomes among inactivated seasonal influenza and live attenuated measles virus vaccines.

We sought to examine ADAR-1 editing of measles and influenza virus genomes derived from inactivated seasonal influenza and live attenuated measles virus vaccines grown on chicken cells as the culture substrate. Using highly sensitive 3DI-PCR (R. Suspène et al.

Analysis of the Legionella longbeachae genome and transcriptome uncovers unique strategies to cause Legionnaires' disease.

Legionella pneumophila and L. longbeachae are two species of a large genus of bacteria that are ubiquitous in nature. L.

Genome sequence of Streptococcus gallolyticus: insights into its adaptation to the bovine rumen and its ability to cause endocarditis.

Streptococcus gallolyticus (formerly known as Streptococcus bovis biotype I) is an increasing cause of endocarditis among streptococci and frequently associated with colon cancer. S. gallolyticus is part of the rumen flora but also a cause of disease in ruminants as well as in birds.

NeMeSys: a biological resource for narrowing the gap between sequence and function in the human pathogen Neisseria meningitidis.

Background: Genome sequences, now available for most pathogens, hold promise for the rational design of new therapies. However, biological resources for genome-scale identification of gene function (notably genes involved in pathogenesis) and/or genes essential for cell viability, which are necessary to achieve this goal, are often sorely lacking. This holds true for Neisseria meningitidis, one of the most feared human bacterial pathogens that causes meningitis and septicemia.

Genome sequence of Vibrio splendidus: an abundant planctonic marine species with a large genotypic diversity.

Vibrio splendidus is a dominant Vibrio species in seawater presenting a remarkable genetic diversity; several strains have been linked to invertebrate's mortality. We report the complete genome sequence of V. splendidus LGP32, an oyster pathogen, and its comparison with partial genome sequences from related strains.