Omics approach to multi-resistant clinical vanB2 Enterococcus faecalis strain. Authors: Luís Pinto, Carmen Torres, Concha Gil, Hugo Santos, Jose Capelo-Martínez, Vítor Borges, João Paulo Gomes, Catarina Silva, Luís Vieira, Patricia Poeta, Gilberto Igrejas

In this study was conducted a detailed proteomic and transcriptomic research on a clinically relevant Vancomycin-resistant Enterococcus (VRE) strain isolated from a patient with urinary tract infection. Previous genotypic profile revealing the presence of resistance genes, with special relevance to the vanB cluster, led us to the development of whole genome sequencing and RNA sequencing (RNA-Seq) in order to detect and quantify the genes expressed by our pathogenic strains. Afterwards, was performed the proteomic identification and comparison methods of both membrane and cytoplasmic sub-proteomes by two-dimensional gel electrophoresis followed by matrix-assisted laser desorption/ionization – time of flight / mass spectrometry. In our work, we have obtained two sub-proteomes (membrane and cytoplasm) of a VRE faecalis strain of clinical background where 118 proteins were identified within a total of 207 spots and confronted to the results obtained by the full transcriptome assay. Several genes and proteins related to stress and cellular response were identified as well as linked to antibiotic and drug response, which is consistent with the state of multi-resistance previously described and so highlighting the serious health problem found in hospitals worldwide. Even though the expression levels are yet not consistent between omics, the information obtained is of much value towards understanding the mechanisms behind antibiotic resistance and virulent bacteria survival capacities.