A concept for international societally relevant microbiology education and microbiology knowledge promulgation in society.

Executive Summary: Microbes are all pervasive in their distribution and influence on the functioning and well-being of humans, life in general and the planet. Microbially-based technologies contribute hugely to the supply of important goods and services we depend upon, such as the provision of food, medicines and clean water. They also offer mechanisms and strategies to mitigate and solve a wide range of problems and crises facing humanity at all levels, including those encapsulated in the sustainable development goals (SDGs) formulated by the United Nations.

Phage-inducible chromosomal minimalist islands (PICMIs), a novel family of small marine satellites of virulent phages.

Phage satellites are bacterial genetic elements that co-opt phage machinery for their own dissemination. Here we identify a family of satellites, named Phage-Inducible Chromosomal Minimalist Islands (PICMIs), that are broadly distributed in marine bacteria of the family Vibrionaceae. A typical PICMI is characterized by reduced gene content, does not encode genes for capsid remodelling, and packages its DNA as a concatemer.

Environmental vibrio phage-bacteria interaction networks reflect the genetic structure of host populations.

Phages depend on their bacterial hosts to replicate. The habitat, density and genetic diversity of host populations are therefore key factors in phage ecology, but our ability to explore their biology depends on the isolation of a diverse and representative collection of phages from different sources. Here, we compared two populations of marine bacterial hosts and their phages collected during a time series sampling program in an oyster farm.

Phage-host coevolution in natural populations.

Coevolution between bacteriophages (phages) and their bacterial hosts occurs through changes in resistance and counter-resistance mechanisms. To assess phage-host evolution in wild populations, we isolated 195 Vibrio crassostreae strains and 243 vibriophages during a 5-month time series from an oyster farm and combined these isolates with existing V. crassostreae and phage isolates.

Rapid evolutionary turnover of mobile genetic elements drives bacterial resistance to phages.

Although it is generally accepted that phages drive bacterial evolution, how these dynamics play out in the wild remains poorly understood. We found that susceptibility to viral killing in marine is mediated by large and highly diverse mobile genetic elements. These phage defense elements display exceedingly fast evolutionary turnover, resulting in differential phage susceptibility among clonal bacterial strains while phage receptors remain invariant.

Vibrio splendidus O-antigen structure: a trade-off between virulence to oysters and resistance to grazers.

A major debate in evolutionary biology is whether virulence is maintained as an adaptive trait and/or evolves to non-virulence. In the environment, virulence traits of non-obligatory parasites are subjected to diverse selective pressures and trade-offs. Here, we focus on a population of Vibrio splendidus that displays moderate virulence for oysters.

Molecular Targets for Coevolutionary Interactions Between Pacific Oyster Larvae and Their Sympatric .

Bacteria of the genus are the most predominant infectious agents threatening marine wildlife and aquaculture. Due to the large genetic diversity of these pathogens, the molecular determinants of virulence are only poorly understood. Furthermore, studies tend to ignore co-evolutionary interactions between different host populations and their locally encountered communities.

Selection of Vibrio crassostreae relies on a plasmid expressing a type 6 secretion system cytotoxic for host immune cells.

Pacific oyster mortality syndrome affects juveniles of Crassostrea gigas oysters and threatens the sustainability of commercial and natural stocks of this species. Vibrio crassostreae (V. crassostreae) has been repeatedly isolated from diseased animals, and the majority of the strains have been demonstrated to be virulent for oysters.

Species-specific mechanisms of cytotoxicity toward immune cells determine the successful outcome of infections.

species cause infectious diseases in humans and animals, but they can also live as commensals within their host tissues. How subverts the host defenses to mount a successful infection remains poorly understood, and this knowledge is critical for predicting and managing disease. Here, we have investigated the cellular and molecular mechanisms underpinning infection and colonization of 2 virulent species in an ecologically relevant host model, oyster, to study interactions with marine species.

Gene Duplication Drives the Evolution of Redundant Regulatory Pathways Controlling Expression of the Major Toxic Secreted Metalloproteases in LGP32.

CsrBs are bacterial highly conserved and multiple-copy noncoding small RNAs (sRNAs) that play major roles in cell physiology and virulence. In the genus, they are known to be regulated by the two-component system VarS/VarA. They modulate the well-characterized quorum sensing pathway controlling virulence and luminescence in and , respectively.

Immune-suppression by OsHV-1 viral infection causes fatal bacteraemia in Pacific oysters.

Infectious diseases are mostly explored using reductionist approaches despite repeated evidence showing them to be strongly influenced by numerous interacting host and environmental factors. Many diseases with a complex aetiology therefore remain misunderstood. By developing a holistic approach to tackle the complexity of interactions, we decipher the complex intra-host interactions underlying Pacific oyster mortality syndrome affecting juveniles of Crassostrea gigas, the main oyster species exploited worldwide.

Ancestral gene acquisition as the key to virulence potential in environmental Vibrio populations.

Diseases of marine animals caused by bacteria of the genus Vibrio are on the rise worldwide. Understanding the eco-evolutionary dynamics of these infectious agents is important for predicting and managing these diseases. Yet, compared to Vibrio infecting humans, knowledge of their role as animal pathogens is scarce.

Ecologically realistic model of infection for exploring the host damage caused by Vibrio aestuarianus.

Although vibrios are frequently associated with marine organisms mortality outbreaks, knowledge on their ecology and pathogenicity is sparse, thus limiting disease management and prophylactic strategies. Here, we investigated V. aestuarianus infection onset and progression in the wild, taking advantage of a 'claire' pond: a semi-closed system with limited seawater renewal, theoretically more adapted to disease transmission.

Eco-evolutionary Dynamics Linked to Horizontal Gene Transfer in Vibrios.

Vibrio is a genus of ubiquitous heterotrophic bacteria found in aquatic environments. Although they are a small percentage of the bacteria in these environments, vibrios can predominate during blooms. Vibrios also play important roles in the degradation of polymeric substances, such as chitin, and in other biogeochemical processes.

The One Health Concept: 10 Years Old and a Long Road Ahead.

Over the past decade, a significant increase in the circulation of infectious agents was observed. With the spread and emergence of epizootics, zoonoses, and epidemics, the risks of pandemics became more and more critical. Human and animal health has also been threatened by antimicrobial resistance, environmental pollution, and the development of multifactorial and chronic diseases.

Nigritoxin is a bacterial toxin for crustaceans and insects.

The Tetraconata (Pancrustacea) concept proposes that insects are more closely related to aquatic crustaceans than to terrestrial centipedes or millipedes. The question therefore arises whether insects have kept crustacean-specific genetic traits that could be targeted by specific toxins. Here we show that a toxin (nigritoxin), originally identified in a bacterial pathogen of shrimp, is lethal for organisms within the Tetraconata and non-toxic to other animals.

Natural resource landscapes of a marine bacterium reveal distinct fitness-determining genes across the genome.

Heterotrophic bacteria exploit diverse microhabitats in the ocean, from particles to transient gradients. Yet the degree to which genes and pathways can contribute to an organism's fitness on such complex and variable natural resource landscapes remains poorly understood. Here, we determine the gene-by-gene fitness of a generalist saprophytic marine bacterium (Vibrio sp.

Vibrio crassostreae, a benign oyster colonizer turned into a pathogen after plasmid acquisition.

Vibrios are frequently associated with oyster mortality; however whether they are the primary causative agent or secondary opportunistic colonizers is not well understood. Here we combine analysis of natural infection dynamics, population genomics and molecular genetics to ask (i) to what extent oysters are passively colonized by Vibrio population present in the surrounding water, (ii) how populations turn over during pathogenicity events and (iii) what genetic factors are responsible for pathogenicity. We identified several populations of Vibrio preferentially associated with oyster tissues.

Colonization of Polystyrene Microparticles by Vibrio crassostreae: Light and Electron Microscopic Investigation.

Microplastics collected at sea harbor a high diversity of microorganisms, including some Vibrio genus members, raising questions about the role of microplastics as a novel ecological niche for potentially pathogenic microorganisms. In the present study, we investigated the adhesion dynamics of Vibrio crassostreae on polystyrene microparticles (micro-PS) using electronic and fluorescence microscopy techniques. Micro-PS were incubated with bacteria in different media (Zobell culture medium and artificial seawater) with or without natural marine aggregates.

Oysters and Vibrios as a Model for Disease Dynamics in Wild Animals.

Disease dynamics in the wild are influenced by a number of ecological and evolutionary factors not addressed by traditional laboratory-based characterization of pathogens. Here we propose the oyster, Crassostrea gigas, as a model for studying the interaction of the environment, bacterial pathogens, and the host in disease dynamics. We show that an important first step is to ask whether the functional unit of pathogenesis is a bacterial clone, a population, or a consortium in order to assess triggers of disease outbreaks and devise appropriate monitoring tools.

Copper homeostasis at the host vibrio interface: lessons from intracellular vibrio transcriptomics.

Recent studies revealed that several vibrio species have evolved the capacity to survive inside host cells. However, it is still often ignored if intracellular stages are required for pathogenicity. Virulence of Vibrio tasmaniensis LGP32, a strain pathogenic for Crassostrea gigas oysters, depends on entry into hemocytes, the oyster immune cells.

The emergence of Vibrio pathogens in Europe: ecology, evolution, and pathogenesis (Paris, 11-12th March 2015).

Global change has caused a worldwide increase in reports of Vibrio-associated diseases with ecosystem-wide impacts on humans and marine animals. In Europe, higher prevalence of human infections followed regional climatic trends with outbreaks occurring during episodes of unusually warm weather. Similar patterns were also observed in Vibrio-associated diseases affecting marine organisms such as fish, bivalves and corals.

Crassostrea gigas mortality in France: the usual suspect, a herpes virus, may not be the killer in this polymicrobial opportunistic disease.

Successive disease outbreaks in oyster (Crassostrea gigas) beds in France have resulted in dramatic losses in production, and subsequent decline in the oyster-farming industry. Deaths of juvenile oysters have been associated with the presence of a herpes virus (OsHV-1 μvar) and bacterial populations of the genus Vibrio. Although the pathogenicity of OsHV-1 μvar, as well as several strains of Vibrio has been demonstrated by experimental infections, our understanding of the complexity of infections occurring in the natural environment remains limited.