title: Investigation of rifampicin resistance mechanisms in Brucella abortus using MS-driven comparative proteomics.
abstract: Mutations in the rpoB gene have already been shown to contribute to rifampicin resistance in many bacterial strains including Brucella species. Resistance against this antibiotic easily occurs and resistant strains have already been detected in human samples. We here present the first research project that combines proteomic, genomic, and microbiological analysis to investigate rifampicin resistance in an in vitro developed rifampicin resistant strain of Brucella abortus 2308. In silico analysis of the rpoB gene was performed and several antibiotics used in the therapy of Brucellosis were used for cross resistance testing. The proteomic profiles were examined and compared using MS-driven comparative proteomics. The resistant strain contained an already described mutation in the rpoB gene, V154F. A correlation between rifampicin resistance and reduced susceptibility on trimethoprim/sulfamethoxazole was detected by E-test and supported by the proteomics results. Using 12 836 MS/MS spectra we identified 6753 peptides corresponding to 456 proteins. The resistant strain presented 39 differentially regulated proteins most of which are involved in various metabolic pathways. Results from our research suggest that rifampicin resistance in Brucella mostly involves mutations in the rpoB gene, excitation of several metabolic processes, and perhaps the use of the already existing secretion mechanisms at a more efficient level.
authors.affiliation: Department of Clinical Bacteriology, Parasitology, Zoonoses and Geographical Medicine, Medical School, University of Crete, GR-71110 Heraklion, Greece.
authors.forename: Vassilios
authors.initials: V
authors.lastname: Sandalakis
authors.forename: Anna
authors.initials: A
authors.lastname: Psaroulaki
authors.forename: Pieter-Jan
authors.initials: PJ
authors.lastname: De Bock
authors.forename: Athanasia
authors.initials: A
authors.lastname: Christidou
authors.forename: Kris
authors.initials: K
authors.lastname: Gevaert
authors.forename: Georgios
authors.initials: G
authors.lastname: Tsiotis
authors.forename: Yiannis
authors.initials: Y
authors.lastname: Tselentis
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D002003:Brucella abortus / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D003198:Computer Simulation; D024881:Drug Resistance, Bacterial; D013058:Mass Spectrometry / Q000379:methods*; D008826:Microbial Sensitivity Tests; D009154:Mutation; D060066:Protein Interaction Maps; D020543:Proteome / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D040901:Proteomics / Q000379:methods*; D012293:Rifampin / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D020543:Proteome; D012293:Rifampin