Publications de Melanie Blokesch

Capsular polysaccharide restrains type VI secretion in Acinetobacter baumannii

Melanie Blokesch, Nicolas Olmo Flaugnatti, Loriane Bader, Mary-Claude Croisier-Coeytaux

The type VI secretion system (T6SS) is a sophisticated, contact-dependent nanomachine involved in interbacterial competition. To function effectively, the T6SS must penetrate the membranes of both attacker and target bacteria. Structures associated with th ...

2025

West African–South American pandemic Vibrio cholerae encodes multiple distinct phage defence systems

Melanie Blokesch, Sandrine Stutzmann, David William Adams, Alexandre Lemopoulos, Loriane Bader, Laurie Righi, Milena Jadwiga Jaskolska

Our understanding of the factors underlying the evolutionary success of different lineages of pandemic Vibrio cholerae remains incomplete. The West African–South American (WASA) lineage of V. cholerae, responsible for the 1991–2001 Latin American cholera e ...

Springer Science and Business Media LLC2025

Exploring Mobile Genetic Elements in Vibrio cholerae

Melanie Blokesch, Alexandre Lemopoulos, Natalia Carolina Drebes Dorr

Members of the bacterial species Vibrio cholerae are known both as prominent constituents of marine environments and as the causative agents of cholera, a severe diarrheal disease. While strains responsible for cholera have been extensively studied over th ...

Oxford University Press (OUP)2025

Molecular mechanism of plasmid elimination by the DdmDE defense system

Melanie Blokesch, Sandrine Stutzmann, David William Adams, Laurie Righi

Seventh pandemic Vibrio cholerae strains contain two pathogenicity islands that encode the DNA defense modules DdmABC and DdmDE. Here we use cryogenic electron microscopy to reveal the mechanistic basis for plasmid defense by DdmDE. A structure of the DdmD ...

American Association for the Advancement of Science2024

Genome sequences of Vibrio cholerae strains isolated in the DRC between 2009 and 2012

Melanie Blokesch, Sandrine Stutzmann, Alexandre Lemopoulos, Natalia Carolina Drebes Dorr

Vibrio cholerae has caused seven cholera pandemics in the past two centuries. The seventh and ongoing pandemic has been particularly severe on the African continent. Here, we report long read-based genome sequences of six V. cholerae strains isolated in th ...

2024

Vibrio cholerae pathogenicity island 2 encodes two distinct types of restriction systems

Melanie Blokesch, David William Adams, Alexandre Lemopoulos, Grazia Vizzarro

In response to predation by bacteriophages and invasion by other mobile genetic elements such as plasmids, bacteria have evolved specialized defense systems that are often clustered together on genomic islands. The O1 El Tor strains of Vibrio cholerae resp ...

American Society for Microbiology2024

Interactions between pili affect the outcome of bacterial competition driven by the type VI secretion system

Melanie Blokesch, Anne-Florence Raphaëlle Bitbol, Alexandre Lemopoulos, Simon Bernhard Otto, Richard Marie Servajean

The bacterial type VI secretion system (T6SS) is a widespread, kin-discriminatory weapon capable of shaping microbial communities. Due to the system’s dependency on contact, cellular interactions can lead to either competition or kin protection. Cell-to-ce ...

2024

Sporadic type VI secretion in seventh pandemic Vibrio cholerae

Melanie Blokesch, Sandrine Stutzmann, Nicolas René Chiaruttini, Alexis Joseph Proutière, Loriane Bader, Lisa Christina Metzger, Natalia Carolina Drebes Dorr, Sandrine Natacha Isaac

Vibrio cholerae is a pathogen that causes disease in millions of people every year by colonizing the small intestine and then secreting the potent cholera toxin. How the pathogen overcomes the colonization barrier created by the host’s natural microbiota i ...

2023

DNA modifications impact natural transformation of Acinetobacter baumannii

Melanie Blokesch, Nicolas Jean Philippe Guex, Christian Iseli, Alexandre Lemopoulos, Nina Vesel

Acinetobacter baumannii is a dangerous nosocomial pathogen, especially due to its ability to rapidly acquire new genetic traits, including antibiotic resistance genes (ARG). In A. baumannii, natural competence for transformation, one of the primary modes o ...

2023

Recombinant bacteria resistant to horizontal gene transfer and phage infection

Melanie Blokesch, David William Adams, Milena Jadwiga Jaskolska

The invention relates to an expression vector encoding a DNA defence system comprising polypeptides derived from Vibrio cholerae, or equivalent functional variants or homologues, conferring resistance to the maintenance of extra-genomic DNA to a recipient ...

2023