title: Global transcriptional response to vancomycin in Mycobacterium tuberculosis.
abstract: In order to gain additional understanding of the physiological mechanisms used by bacteria to maintain surface homeostasis and to identify potential targets for new antibacterial drugs, we analysed the variation of the Mycobacterium tuberculosis transcriptional profile in response to inhibitory and subinhibitory concentrations of vancomycin. Our analysis identified 153 genes differentially regulated after exposing bacteria to a concentration of the drug ten times higher than the MIC, and 141 genes differentially expressed when bacteria were growing in a concentration of the drug eightfold lower than the MIC. Hierarchical clustering analysis indicated that the response to these different conditions is different, although with some overlap. This approach allowed us to identify several genes whose products could be involved in the protection from antibiotic stress targeting the envelope and help to confer the basal level of M. tuberculosis resistance to antibacterial drugs, such as Rv2623 (UspA-like), Rv0116c, PE20-PPE31, PspA and proteins related to toxin-antitoxin systems. Moreover, we also demonstrated that the alternative sigma factor sigma(E) confers basal resistance to vancomycin, once again underlining its importance in the physiology of the mycobacterial surface stress response.
authors.affiliation: Department of Biology, University of Padua, 35100 Padua, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Provvedi
authors.affiliation: Department of Histology, Microbiology and Medical Biotechnologies, University of Padua, 35100 Padua, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Boldrin
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
authors.forename: Francesco
authors.initials: F
authors.lastname: Falciani
authors.affiliation: Department of Histology, Microbiology and Medical Biotechnologies, University of Padua, 35100 Padua, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Palù
authors.affiliation: Department of Histology, Microbiology and Medical Biotechnologies, University of Padua, 35100 Padua, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Manganelli