Browsing by Author "Viala, Didier"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- Next-Generation Sequencing and MALDI Mass Spectrometry in the Study of Multiresistant Processed Meat Vancomycin-Resistant Enterococci (VRE)Publication . Sabença, Carolina; de Sousa, Telma; Oliveira, Soraia; Viala, Didier; Théron, Laetitia; Chambon, Christophe; Hébraud, Michel; Beyrouthy, Racha; Bonnet, Richard; Caniça, Manuela; Poeta, Patrícia; Igrejas, GilbertoVancomycin-resistant enterococci (VRE), due to their intrinsic resistance to various commonly used antibiotics and their malleable genome, make the treatment of infections caused by these bacteria less effective. The aims of this work were to characterize isolates of Enterococcus spp. that originated from processed meat, through phenotypic and genotypic techniques, as well as to detect putative antibiotic resistance biomarkers. The 19 VRE identified had high resistance to teicoplanin (89%), tetracycline (94%), and erythromycin (84%) and a low resistance to kanamycin (11%), gentamicin (11%), and streptomycin (5%). Based on a Next-Generation Sequencing NGS technique, most isolates were vanA-positive. The most prevalent resistance genes detected were erm(B) and aac(6')-Ii, conferring resistance to the classes of macrolides and aminoglycosides, respectively. MALDI-TOF mass spectrometry (MS) analysis detected an exclusive peak of the Enterococcus genus at m/z (mass-to-charge-ratio) 4428 ± 3, and a peak at m/z 6048 ± 1 allowed us to distinguish Enterococcusfaecium from the other species. Several statistically significant protein masses associated with resistance were detected, such as peaks at m/z 6358.27 and m/z 13237.3 in ciprofloxacin resistance isolates. These results reinforce the relevance of the combined and complementary NGS and MALDI-TOF MS techniques for bacterial characterization.
- Subproteomic signature comparison of in vitro selected fluoroquinolone resistance and ciprofloxacin stress in Salmonella Typhimurium DT104BPublication . Correia, Susana; Hébraud, Michel; Chafsey, Ingrid; Chambon, Christophe; Viala, Didier; Torres, Carmen; Caniça, Manuela; Capelo, José Luis; Poeta, Patrícia; Igrejas, GilbertoBackground: Fluoroquinolone resistance in nontyphoidal Salmonella is a situation of serious and international concern, particularly in S. Typhimurium DT104B multiresistant strains. Although known to be multifactorial, fluoroquinolone resistance is still far from a complete understanding. Methods: Subproteome changes between an experimentally selected fluoroquinolone-resistant strain (Se6-M) and its parent strain (Se6), and also in Se6-M under ciprofloxacin (CIP) stress, were evaluated in order to give new insights into the mechanisms involved. Proteomes were compared at the intracellular and membrane levels by a 2-DE~LC-MS/MS and a shotgun LC-MS/MS approach, respectively. Results: In total, 35 differentially abundant proteins were identified when comparing Se6 with Se6-M (25 more abundant in Se6 and 10 more abundant in Se6-M) and 82 were identified between Se6-M and Se6-M+CIP (51 more abundant in Se6-M and 31 more abundant under ciprofloxacin stress). Conclusion: Several proteins with known and possible roles in quinolone resistance were identified which provide important information about mechanism-related differential protein expression, supporting the current knowledge and also leading to new testable hypotheses on the mechanism of action of fluoroquinolone drugs.