A carregar...
2 resultados
Resultados da pesquisa
A mostrar 1 - 2 de 2
- Biofilm Formation by ST17 and ST19 Strains of Streptococcus agalactiaePublication . Silvestre, Inês; Borrego, Maria José; Jordão, LuísaBacterial biofilms are an important virulence factor with a vital role in evasion from the host immune system, colonization and infection. The aim of the present study was to evaluate in vitro the effects of three environmental factors (H+ , glucose and human plasma) in biofilm formation, by carrier and invasive S. agalactiae strains of ST17 and ST19 sequence types, including DNase producers and nonproducers. Bacteria ability to assemble biofilms was classified based on crystal violet assay. Biofilm formation was also monitored by scanning electron microscopy. Depending on the growth medium used, each bacterial isolate could fit in different biofilm production categories. Our data showed that optimal conditions for S. agalactiae biofilm assembly were reached after 48 h incubation at pH 7.6 in the presence of glucose and inactivated human plasma. In the presence of inactivated human plasma, the biofilm biomass of ST19 strains experienced a higher increase than ST17 strains. The composition of the extracellular polymeric matrix of the three strongest biofilm producers (all from ST17) was accessed by enzymatic digestion of mature biofilms and proteins were shown to be the predominant component. The detailed identification of the extracellular protein components should contribute to the development of new therapeutic strategies to fight S. agalactiae infections.
- Undetected circulation of monkeypox virus in Portugal: Evidence for a 50-day gap before first detectionPublication . Cordeiro, Rita; Batista, Fernando da Conceição; Pelerito, Ana; De carvalho, Isabel; Lopo, Sílvia; Neves, Raquel; Rocha, Raquel; Palminha, Paula; Borrego, Maria José; Nuncio, MS; Gomes, João PauloAs mpox continues to spread globally, proactive monitoring and preparedness are crucial to minimize impact and enhance response strategies. Using a mathematical model combining a negative binomial distribution with Richards' logistic curve, we reconstructed the hidden phase of mpox transmission in Portugal, offering insights into the timing and dynamics of the initial outbreak. The analysis of 950 PCR-positive and 986 negative cases suggested that symptom onset occurred between March 24 and April 2, 2022, with March 27 identified as the most probable date. This study delineates the likely period of silent circulation of MPXV in Portugal, providing a clearer understanding of early outbreak dynamics and surveillance performance. Possible imperfections in early diagnostic testing and limited awareness of mpox may have contributed to delayed recognition of the outbreak. By demonstrating how retrospective mathematical modelling can estimate undetected transmission periods, our findings highlight the value of such approaches in epidemic reconstruction and underscore the importance of strengthening early surveillance systems to detect undiagnosed transmission of mpox in non-endemic countries.