Project description:Ochrobactrum anthropi is a gram-negative rod belonging to the Brucellaceae family, able to colonize a variety of environments, and actually reported as a human opportunistic pathogen. Despite its low virulence, the bacterium causes a growing number of hospital-acquired infections mainly, but not exclusively, in immunocompromised patients. The aim of this study was to obtain an overview of the global proteome changes occurring in O. anthropi in response to different growth temperatures, in order to achieve a major understanding of the mechanisms by which the bacterium adapts to different habitats and to identify some potential virulence factors. Combined quantitative mass spectrometry-based proteomics and bioinformatics approaches were carried out on two O. anthropi strains grown at temperatures miming soil/plants habitat (25 C) and human host environment (37 C), respectively. Proteomic analysis led to the identification of over 150 differentially expressed proteins in both strains, out of over 1200 total protein identifications. Among them, proteins responsible for heat shock response (DnaK, GrpE), motility (FliC, FlgG, FlgE), and putative virulence factors (TolB) were identified. The study represents the first quantitative proteomic analysis of O. anthropi performed by high-resolution quantitative mass spectrometry.
Project description:Staphylococcus aureus is an opportunistic pathogen capable of causing various infections ranging from superficial skin infections to life-threatening severe diseases, including pneumonia and sepsis. This bacterium is attached to biotic and abiotic surfaces and forms biofilms that are resistant to conventional antimicrobial agents and clearance by host defenses. Infections associated with biofilms may result in longer hospitalizations, a need for surgery, and may even result in death. Agents that inhibit the formation of biofilms and virulence without affecting bacterial growth to avoid the development of drug resistance could be useful for therapeutic purposes. In this regard, we identified and isolated a small cyclic peptide, gurmarin, from a plant source that inhibited the formation of S. aureus biofilm without affecting the growth rate of the bacterium. We determined the gene expression of S. aureus biofilm treated with gurmarin and compared it to the untreated control biofilms. Differentially expressed genes were identified and their roles in the inhibition of S. aureus biofilms by gurmarin were analyzed.
