The Response Regulator OmpR Negatively Controls the Expression of Genes Implicated in Tilimycin and Tilivalline Cytotoxin Production in .

toxigenic strains represent a critical health threat, mainly due to their link to antibiotic-associated hemorrhagic colitis. This serious condition results from the bacteria's ability to produce tilimycin and tilivalline cytotoxins. Our research highlights the pivotal role of OmpR, a key regulator within the EnvZ/OmpR two-component system, in controlling the virulence factors associated with .

High-risk clones harboring β-lactamases: 2024 update.

Carbapenem-resistant is defined by the World Health Organization as a "high priority" in developing new antimicrobials. Indeed, the emergence and spread of multidrug-resistant (MDR) or extensively drug-resistant (XDR) bacteria increase the morbidity and mortality risk of infected patients. Genomic variants of that display phenotypes of MDR/XDR have been defined as high-risk global clones.

The transcriptional regulator Lrp activates the expression of genes involved in the biosynthesis of tilimycin and tilivalline enterotoxins in .

The toxigenic strains secrete tilymicin and tilivalline enterotoxins, which cause antibiotic-associated hemorrhagic colitis. Both enterotoxins are non-ribosomal peptides synthesized by enzymes encoded in two divergent operons clustered in a pathogenicity island. The transcriptional regulator Lrp (eucine-responsive egulatory rotein) controls the expression of several bacterial genes involved in virulence.

Novel Populations of Under Hypoxia and Starvation: Some Insights on Cell Viability and Morphological Changes.

The general features of the shift to a dormant state in mycobacterial species include several phenotypic changes, reduced metabolic activities, and increased resistance to host and environmental stress conditions. In this study, we aimed to provide novel insights into the viability state and morphological changes in dormant that contribute to its long-term survival under starvation or hypoxia. To this end, we conducted assays to evaluate cell viability, morphological changes and gene expression.