Browsing by Author "Oliveira, Manuela"
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- Characterization of multidrug-resistant diabetic foot ulcer enterococciPublication . Semedo-Lemsaddek, Teresa; Mottola, Carla; Alves-Barroco, Cynthia; Cavaco-Silva, Patrícia; Tavares, Luís; Oliveira, ManuelaIntroduction: Diabetes mellitus is a highly prevalent chronic progressive disease with complications that include diabetic-foot ulcers. Methods: Enterococci isolated from diabetic-foot infections were identified, evaluated by macrorestriction analysis, and screened for virulence traits and antimicrobial resistance. Results: All isolates were considered multidrug-resistant, cytolysin and gelatinase producers, and the majority also demonstrated the ability to produce biofilms. Conclusions: These results indicate the importance of enterococci in diabetic-foot infection development and persistence, especially regarding their biofilm-forming ability and resistance to clinically relevant antibiotics.
- In vitro design of a novel lytic bacteriophage cocktail with therapeutic potential against organisms causing diabetic foot infectionsPublication . Mendes, João J.; Leandro, Clara; Mottola, Carla; Barbosa, Raquel; Silva, Filipa A.; Oliveira, Manuela; Vilela, Cristina L.; Melo-Cristino, José; Górski, Andrzej; Pimentel, Madalena; São-José, Carlos; Cavaco-Silva, Patrícia; Garcia, MiguelIn patients with diabetes mellitus, foot infections pose a significant risk. These are complex infections commonly caused by Staphylococcus aureus, Pseudomonas aeruginosa and Acinetobacter baumannii, all of which are potentially susceptible to bacteriophages. Here, we characterized five bacteriophages that we had determined previously to have antimicrobial and wound-healing potential in chronic S. aureus, P. aeruginosa and A. baumannii infections. Morphological and genetic features indicated that the bacteriophages were lytic members of the family Myoviridae or Podoviridae and did not harbour any known bacterial virulence genes. Combinations of the bacteriophages had broad host ranges for the different target bacterial species. The activity of the bacteriophages against planktonic cells revealed effective, early killing at 4 h, followed by bacterial regrowth to pre-treatment levels by 24 h. Using metabolic activity as a measure of cell viability within established biofilms, we found significant cell impairment following bacteriophage exposure. Repeated treatment every 4 h caused a further decrease in cell activity. The greatest effects on both planktonic and biofilm cells occurred at a bacteriophage : bacterium input multiplicity of 10. These studies on both planktonic cells and established biofilms allowed us to better evaluate the effects of a high input multiplicity and a multiple-dose treatment protocol, and the findings support further clinical development of bacteriophage therapy.