DDI - Artigos em revistas internacionais
URI permanente para esta coleção:
Navegar
Percorrer DDI - Artigos em revistas internacionais por Domínios Científicos e Tecnológicos (FOS) "Ciências Naturais"
A mostrar 1 - 3 de 3
Resultados por página
Opções de ordenação
- Exploring flagellar contributions to motility and virulence in Arcobacter butzleriPublication . Santos, Raquel; Mateus, Cristiana; Oleastro, Mónica; Ferreira, SusanaFlagella is a well-known bacterial structure crucial for motility, which also plays pivotal roles in pathogenesis. Arcobacter butzleri, an enteropathogen, possesses a distinctive polar flagellum whose functional aspects remain largely unexplored. Upon investigating the factors influencing A. butzleri motility, we uncovered that environmental conditions like temperature, oxygen levels, and nutrient availability play a significant role. Furthermore, compounds that are found in human gut, such as short-chain fatty acids, mucins and bile salts, have a role in modulating the motility, and in turn, the pathogenicity of A. butzleri. Further investigation demonstrated that A. butzleri ΔflaA mutant showed a reduction in motility with a close to null average velocity, as well as a reduction on biofilm formation. In addition, compared with the wild-type, the ΔflaA mutant showed a decreased ability to invade Caco-2 cells and to adhere to mucins. Taken together, our findings support the role of environmental conditions and gut host associated compounds influencing key physiological aspects of the gastrointestinal pathogen A. butzleri, such as motility, and support the role of the flagellum on bacterial virulence.
- Genomic Analysis of Antibiotic Resistance and Virulence Profiles in Escherichia coli Linked to Sternal Bursitis in Chickens: A One Health PerspectivePublication . Ribeiro, Jessica; Silva, Vanessa; Freitas, Catarina; Pinto, Pedro; Vieira-Pinto, Madalena; Batista, Rita; Nunes, Alexandra; Gomes, João Paulo; Pereira, José Eduardo; Igrejas, Gilberto; Barros, Lillian; Heleno, Sandrina A.; Reis, Filipa S.; Poeta, PatríciaAbstract: Sternal bursitis is an underexplored lesion in poultry, often overlooked in microbiological diagnostics. In this study, we characterized 36 Escherichia coli isolates recovered from sternal bursitis in broiler chickens, combining phenotypic antimicrobial susceptibility testing, PCRbased screening, and whole genome sequencing (WGS). The genetic analysis revealed a diverse population spanning 15 sequence types, including ST155, ST201, and ST58. Resistance to tetracycline and ciprofloxacin was common, and several isolates carried genes encoding β-lactamases, including blaTEM-1B. Chromosomal mutations associated with quinolone and fosfomycin resistance (e.g., gyrA p.S83L, glpT_E448K) were also identified. WGS revealed a high number of virulence-associated genes per isolate (58–96), notably those linked to adhesion (fim, ecp clusters), secretion systems (T6SS), and iron acquisition (ent, fep, fes), suggesting strong pathogenic potential. Many isolates harbored virulence markers typical of ExPEC/APEC, such as iss, ompT, and traT, even in the absence of multidrug resistance. Our findings suggest that E. coli from sternal bursitis may act as reservoirs of resistance and virulence traits relevant to animal and public health. This highlights the need for including such lesions in genomic surveillance programs and reinforces the importance of integrated One Health approaches.
- Screening and in silico characterization of prophages in Helicobacter pylori clinical strainsPublication . Ferreira, Rute; Pinto, Graça; Presa, Eva; Oleastro, Mónica; Silva, Catarina; Vieira, Luís; Sousa, Claúdia; Pires, Diana; Figueiredo, Ceu; Melo, LuísThe increase of antibiotic resistance calls for alternatives to control Helicobacter pylori, a Gram-negative bacterium associated with various gastric diseases. Bacteriophages (phages) can be highly effective in the treatment of pathogenic bacteria. Here, we developed a method to identify prophages in H. pylori genomes aiming at their future use in therapy. A polymerase chain reaction (PCR)-based technique tested five primer pairs on 74 clinical H. pylori strains. After the PCR screening, 14 strains most likely to carry prophages were fully sequenced. After that, a more holistic approach was taken by studying the complete genome of the strains. This study allowed us to identify 12 intact prophage sequences, which were then characterized concerning their morphology, virulence, and antibiotic-resistance genes. To understand the variability of prophages, a phylogenetic analysis using the sequences of all H. pylori phages reported to date was performed. Overall, we increased the efficiency of identifying complete prophages to 54.1 %. Genes with homology to potential virulence factors were identified in some new prophages. Phylogenetic analysis revealed a close relationship among H. pylori-phages, although there are phages with different geographical origins. This study provides a deeper understanding of H. pylori-phages, providing valuable insights into their potential use in therapy.